RE: [PATCH v5 5/7] ocxl: Expose the thread_id needed for wait on POWER9

[Alastair D'Silva]

> -Original Message-
> From: Frederic Barrat <fbar...@linux.ibm.com>
> Sent: Friday, 11 May 2018 7:25 PM
> To: Alastair D'Silva <alast...@au1.ibm.com>; linuxppc-...@lists.ozlabs.org
> Cc: linux-ker...@vger.kernel.org; linux-doc@vger.kernel.org;
> mi...@neuling.org; vaib...@linux.vnet.ibm.com;
> aneesh.ku...@linux.vnet.ibm.com; ma...@debian.org;
> fe...@linux.vnet.ibm.com; pombreda...@nexb.com;
> suka...@linux.vnet.ibm.com; npig...@gmail.com;
> gre...@linuxfoundation.org; a...@arndb.de;
> andrew.donnel...@au1.ibm.com; fbar...@linux.vnet.ibm.com;
> cor...@lwn.net; Alastair D'Silva <alast...@d-silva.org>
> Subject: Re: [PATCH v5 5/7] ocxl: Expose the thread_id needed for wait on
> POWER9
> 
> 
> 
> Le 11/05/2018 à 08:13, Alastair D'Silva a écrit :
> > From: Alastair D'Silva <alast...@d-silva.org>
> >
> > In order to successfully issue as_notify, an AFU needs to know the TID
> > to notify, which in turn means that this information should be
> > available in userspace so it can be communicated to the AFU.
> >
> > Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
> > ---
> 
> Ok, so we keep the limitation of having only one thread per context able to
> call 'wait', even though we don't have to worry about depleting the pool of
> TIDs any more. I think that's acceptable, though we don't really have a reason
> to justify it any more. Any reason you want to keep it that way?
> 

No strong reason, just trying to minimise the amount of changes. We can always 
expand the scope later, if we have a use-case for it.

>Fred
> 
> 
> >   drivers/misc/ocxl/context.c   |  5 ++-
> >   drivers/misc/ocxl/file.c  | 53 +++
> >   drivers/misc/ocxl/link.c  | 36 +
> >   drivers/misc/ocxl/ocxl_internal.h |  1 +
> >   include/misc/ocxl.h   |  9 ++
> >   include/uapi/misc/ocxl.h  |  8 +
> >   6 files changed, 111 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
> > index 909e8807824a..95f74623113e 100644
> > --- a/drivers/misc/ocxl/context.c
> > +++ b/drivers/misc/ocxl/context.c
> > @@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct
> ocxl_afu *afu,
> > mutex_init(>xsl_error_lock);
> > mutex_init(>irq_lock);
> > idr_init(>irq_idr);
> > +   ctx->tidr = 0;
> > +
> > /*
> >  * Keep a reference on the AFU to make sure it's valid for the
> >  * duration of the life of the context @@ -65,6 +67,7 @@ int
> > ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
> >   {
> > int rc;
> >
> > +   // Locks both status & tidr
> > mutex_lock(>status_mutex);
> > if (ctx->status != OPENED) {
> > rc = -EIO;
> > @@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64
> amr)
> > }
> >
> > rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
> > -   current->mm->context.id, 0, amr, current->mm,
> > +   current->mm->context.id, ctx->tidr, amr, current-
> >mm,
> > xsl_fault_error, ctx);
> > if (rc)
> > goto out;
> > diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c index
> > 038509e5d031..eb409a469f21 100644
> > --- a/drivers/misc/ocxl/file.c
> > +++ b/drivers/misc/ocxl/file.c
> > @@ -5,6 +5,8 @@
> >   #include 
> >   #include 
> >   #include 
> > +#include 
> > +#include 
> >   #include "ocxl_internal.h"
> >
> >
> > @@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct
> ocxl_context *ctx,
> > return 0;
> >   }
> >
> > +#ifdef CONFIG_PPC64
> > +static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
> > +   struct ocxl_ioctl_p9_wait __user *uarg) {
> > +   struct ocxl_ioctl_p9_wait arg;
> > +
> > +   memset(, 0, sizeof(arg));
> > +
> > +   if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
> > +   enum ocxl_context_status status;
> > +
> > +   // Locks both status & tidr
> > +   mutex_lock(>status_mutex);
> > +   if (!ctx->tidr) {
> > +   if (set_thread_tidr(current))
> > +   return -ENOENT;
> > +
> > +   ctx->tidr = current->thread.tidr;
> > +   }
> > +
> > +   status = ctx->statu

[PATCH v5 5/7] ocxl: Expose the thread_id needed for wait on POWER9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order to successfully issue as_notify, an AFU needs to know the TID
to notify, which in turn means that this information should be
available in userspace so it can be communicated to the AFU.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/context.c   |  5 ++-
 drivers/misc/ocxl/file.c  | 53 +++
 drivers/misc/ocxl/link.c  | 36 +
 drivers/misc/ocxl/ocxl_internal.h |  1 +
 include/misc/ocxl.h   |  9 ++
 include/uapi/misc/ocxl.h  |  8 +
 6 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 909e8807824a..95f74623113e 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct 
ocxl_afu *afu,
mutex_init(>xsl_error_lock);
mutex_init(>irq_lock);
idr_init(>irq_idr);
+   ctx->tidr = 0;
+
/*
 * Keep a reference on the AFU to make sure it's valid for the
 * duration of the life of the context
@@ -65,6 +67,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 {
int rc;
 
+   // Locks both status & tidr
mutex_lock(>status_mutex);
if (ctx->status != OPENED) {
rc = -EIO;
@@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
}
 
rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
-   current->mm->context.id, 0, amr, current->mm,
+   current->mm->context.id, ctx->tidr, amr, current->mm,
xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 038509e5d031..eb409a469f21 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -5,6 +5,8 @@
 #include 
 #include 
 #include 
+#include 
+#include 
 #include "ocxl_internal.h"
 
 
@@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct ocxl_context 
*ctx,
return 0;
 }
 
+#ifdef CONFIG_PPC64
+static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
+   struct ocxl_ioctl_p9_wait __user *uarg)
+{
+   struct ocxl_ioctl_p9_wait arg;
+
+   memset(, 0, sizeof(arg));
+
+   if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
+   enum ocxl_context_status status;
+
+   // Locks both status & tidr
+   mutex_lock(>status_mutex);
+   if (!ctx->tidr) {
+   if (set_thread_tidr(current))
+   return -ENOENT;
+
+   ctx->tidr = current->thread.tidr;
+   }
+
+   status = ctx->status;
+   mutex_unlock(>status_mutex);
+
+   if (status == ATTACHED) {
+   int rc;
+   struct link *link = ctx->afu->fn->link;
+
+   rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr);
+   if (rc)
+   return rc;
+   }
+
+   arg.thread_id = ctx->tidr;
+   } else
+   return -ENOENT;
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+#endif
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
+   x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -186,6 +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
(struct ocxl_ioctl_metadata __user *) args);
break;
 
+#ifdef CONFIG_PPC64
+   case OCXL_IOCTL_ENABLE_P9_WAIT:
+   rc = afu_ioctl_enable_p9_wait(ctx,
+   (struct ocxl_ioctl_p9_wait __user *) args);
+   break;
+#endif
+
default:
rc = -EINVAL;
}
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 656e8610eec2..88876ae8f330 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -544,6 +544,42 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 
pidr, u32 tidr,
 }
 EXPORT_SYMBOL_GPL(ocxl_link_add_pe);
 
+int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid)
+{
+   st

[PATCH v5 7/7] ocxl: Document new OCXL IOCTLs

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 Documentation/accelerators/ocxl.rst | 11 +++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/accelerators/ocxl.rst 
b/Documentation/accelerators/ocxl.rst
index ddcc58d01cfb..14cefc020e2d 100644
--- a/Documentation/accelerators/ocxl.rst
+++ b/Documentation/accelerators/ocxl.rst
@@ -157,6 +157,17 @@ OCXL_IOCTL_GET_METADATA:
   Obtains configuration information from the card, such at the size of
   MMIO areas, the AFU version, and the PASID for the current context.
 
+OCXL_IOCTL_ENABLE_P9_WAIT:
+
+  Allows the AFU to wake a userspace thread executing 'wait'. Returns
+  information to userspace to allow it to configure the AFU. Note that
+  this is only available on POWER9.
+
+OCXL_IOCTL_GET_FEATURES:
+
+  Reports on which CPU features that affect OpenCAPI are usable from
+  userspace.
+
 
 mmap
 
-- 
2.17.0

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v5 4/7] ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The function removes the process element from NPU cache.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/pnv-ocxl.h   | 2 +-
 arch/powerpc/platforms/powernv/ocxl.c | 4 ++--
 drivers/misc/ocxl/link.c  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pnv-ocxl.h 
b/arch/powerpc/include/asm/pnv-ocxl.h
index f6945d3bc971..208b5503f4ed 100644
--- a/arch/powerpc/include/asm/pnv-ocxl.h
+++ b/arch/powerpc/include/asm/pnv-ocxl.h
@@ -28,7 +28,7 @@ extern int pnv_ocxl_map_xsl_regs(struct pci_dev *dev, void 
__iomem **dsisr,
 extern int pnv_ocxl_spa_setup(struct pci_dev *dev, void *spa_mem, int PE_mask,
void **platform_data);
 extern void pnv_ocxl_spa_release(void *platform_data);
-extern int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle);
+extern int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int 
pe_handle);
 
 extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
 extern void pnv_ocxl_free_xive_irq(u32 irq);
diff --git a/arch/powerpc/platforms/powernv/ocxl.c 
b/arch/powerpc/platforms/powernv/ocxl.c
index fa9b53af3c7b..8c65aacda9c8 100644
--- a/arch/powerpc/platforms/powernv/ocxl.c
+++ b/arch/powerpc/platforms/powernv/ocxl.c
@@ -475,7 +475,7 @@ void pnv_ocxl_spa_release(void *platform_data)
 }
 EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
 
-int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle)
+int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
 {
struct spa_data *data = (struct spa_data *) platform_data;
int rc;
@@ -483,7 +483,7 @@ int pnv_ocxl_spa_remove_pe(void *platform_data, int 
pe_handle)
rc = opal_npu_spa_clear_cache(data->phb_opal_id, data->bdfn, pe_handle);
return rc;
 }
-EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe);
+EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe_from_cache);
 
 int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr)
 {
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index f30790582dc0..656e8610eec2 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -599,7 +599,7 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
 * On powerpc, the entry needs to be cleared from the context
 * cache of the NPU.
 */
-   rc = pnv_ocxl_spa_remove_pe(link->platform_data, pe_handle);
+   rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
WARN_ON(rc);
 
pe_data = radix_tree_delete(>pe_tree, pe_handle);
-- 
2.17.0

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v5 3/7] powerpc: use task_pid_nr() for TID allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The current implementation of TID allocation, using a global IDR, may
result in an errant process starving the system of available TIDs.
Instead, use task_pid_nr(), as mentioned by the original author. The
scenario described which prevented it's use is not applicable, as
set_thread_tidr can only be called after the task struct has been
populated.

In the unlikely event that 2 threads share the TID and are waiting,
all potential outcomes have been determined safe.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/switch_to.h |   1 -
 arch/powerpc/kernel/process.c| 122 ++-
 2 files changed, 28 insertions(+), 95 deletions(-)

diff --git a/arch/powerpc/include/asm/switch_to.h 
b/arch/powerpc/include/asm/switch_to.h
index be8c9fa23983..5b03d8a82409 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -94,6 +94,5 @@ static inline void clear_task_ebb(struct task_struct *t)
 extern int set_thread_uses_vas(void);
 
 extern int set_thread_tidr(struct task_struct *t);
-extern void clear_thread_tidr(struct task_struct *t);
 
 #endif /* _ASM_POWERPC_SWITCH_TO_H */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 3b00da47699b..c5b8e53acbae 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1496,103 +1496,41 @@ int set_thread_uses_vas(void)
 }
 
 #ifdef CONFIG_PPC64
-static DEFINE_SPINLOCK(vas_thread_id_lock);
-static DEFINE_IDA(vas_thread_ida);
-
-/*
- * We need to assign a unique thread id to each thread in a process.
+/**
+ * Assign a TIDR (thread ID) for task @t and set it in the thread
+ * structure. For now, we only support setting TIDR for 'current' task.
  *
- * This thread id, referred to as TIDR, and separate from the Linux's tgid,
- * is intended to be used to direct an ASB_Notify from the hardware to the
- * thread, when a suitable event occurs in the system.
+ * Since the TID value is a truncated form of it PID, it is possible
+ * (but unlikely) for 2 threads to have the same TID. In the unlikely event
+ * that 2 threads share the same TID and are waiting, one of the following
+ * cases will happen:
  *
- * One such event is a "paste" instruction in the context of Fast Thread
- * Wakeup (aka Core-to-core wake up in the Virtual Accelerator Switchboard
- * (VAS) in POWER9.
+ * 1. The correct thread is running, the wrong thread is not
+ * In this situation, the correct thread is woken and proceeds to pass it's
+ * condition check.
  *
- * To get a unique TIDR per process we could simply reuse task_pid_nr() but
- * the problem is that task_pid_nr() is not yet available copy_thread() is
- * called. Fixing that would require changing more intrusive arch-neutral
- * code in code path in copy_process()?.
+ * 2. Neither threads are running
+ * In this situation, neither thread will be woken. When scheduled, the waiting
+ * threads will execute either a wait, which will return immediately, followed
+ * by a condition check, which will pass for the correct thread and fail
+ * for the wrong thread, or they will execute the condition check immediately.
  *
- * Further, to assign unique TIDRs within each process, we need an atomic
- * field (or an IDR) in task_struct, which again intrudes into the arch-
- * neutral code. So try to assign globally unique TIDRs for now.
+ * 3. The wrong thread is running, the correct thread is not
+ * The wrong thread will be woken, but will fail it's condition check and
+ * re-execute wait. The correct thread, when scheduled, will execute either
+ * it's condition check (which will pass), or wait, which returns immediately
+ * when called the first time after the thread is scheduled, followed by it's
+ * condition check (which will pass).
  *
- * NOTE: TIDR 0 indicates that the thread does not need a TIDR value.
- *  For now, only threads that expect to be notified by the VAS
- *  hardware need a TIDR value and we assign values > 0 for those.
- */
-#define MAX_THREAD_CONTEXT ((1 << 16) - 1)
-static int assign_thread_tidr(void)
-{
-   int index;
-   int err;
-   unsigned long flags;
-
-again:
-   if (!ida_pre_get(_thread_ida, GFP_KERNEL))
-   return -ENOMEM;
-
-   spin_lock_irqsave(_thread_id_lock, flags);
-   err = ida_get_new_above(_thread_ida, 1, );
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-
-   if (err == -EAGAIN)
-   goto again;
-   else if (err)
-   return err;
-
-   if (index > MAX_THREAD_CONTEXT) {
-   spin_lock_irqsave(_thread_id_lock, flags);
-   ida_remove(_thread_ida, index);
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-   return -ENOMEM;
-   }
-
-   return index;
-}
-
-static void free_thread_tidr(int id)
-{
-   unsigned long flags;
-
-   spin_l

[PATCH v5 1/7] powerpc: Add TIDR CPU feature for POWER9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

This patch adds a CPU feature bit to show whether the CPU has
the TIDR register available, enabling as_notify/wait in userspace.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/cputable.h | 3 ++-
 arch/powerpc/kernel/dt_cpu_ftrs.c   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/cputable.h 
b/arch/powerpc/include/asm/cputable.h
index 66fcab13c8b4..9c0a3083571b 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -215,6 +215,7 @@ static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_P9_TM_HV_ASSIST
LONG_ASM_CONST(0x1000)
 #define CPU_FTR_P9_TM_XER_SO_BUG   LONG_ASM_CONST(0x2000)
 #define CPU_FTR_P9_TLBIE_BUG   LONG_ASM_CONST(0x4000)
+#define CPU_FTR_P9_TIDR
LONG_ASM_CONST(0x8000)
 
 #ifndef __ASSEMBLY__
 
@@ -462,7 +463,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY | \
-   CPU_FTR_P9_TLBIE_BUG)
+   CPU_FTR_P9_TLBIE_BUG | CPU_FTR_P9_TIDR)
 #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \
 (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 8ab51f6ca03a..41e5b69f 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -716,6 +716,7 @@ static __init void cpufeatures_cpu_quirks(void)
if ((version & 0x) == 0x004e) {
cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+   cur_cpu_spec->cpu_features |= CPU_FTR_P9_TIDR;
}
 
/*
-- 
2.17.0

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v5 0/7] ocxl: Implement Power9 as_notify/wait for OpenCAPI

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The Power 9 as_notify/wait feature provides a lower latency way to
signal a thread that work is complete. This series enables the use of
this feature from OpenCAPI adapters, as well as addressing a potential
starvation issue when allocating thread IDs.

Changelog:
v5:
  Remove stray brace
  Fix bad rename of ocxl_ioctl_platform to ocxl_ioctl_features
v4:
  Remove the "unique" statement from the set_thread_tidr function and
move the text explaining why it is safe from the commit message
to the function description
v3:
  Fix references to POWER9
  Remove stray whitespace edit from docs
  Add more details to commit message for "use task_pid_nr()"
  Retitle patch 6 to indicate OCXL rather than CPU features
v2:
  Rename get_platform IOCTL to get_features
  Move stray edit from patch 1 to patch 3

Alastair D'Silva (7):
  powerpc: Add TIDR CPU feature for POWER9
  powerpc: Use TIDR CPU feature to control TIDR allocation
  powerpc: use task_pid_nr() for TID allocation
  ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action
  ocxl: Expose the thread_id needed for wait on POWER9
  ocxl: Add an IOCTL so userspace knows what OCXL features are available
  ocxl: Document new OCXL IOCTLs

 Documentation/accelerators/ocxl.rst   |  11 
 arch/powerpc/include/asm/cputable.h   |   3 +-
 arch/powerpc/include/asm/pnv-ocxl.h   |   2 +-
 arch/powerpc/include/asm/switch_to.h  |   1 -
 arch/powerpc/kernel/dt_cpu_ftrs.c |   1 +
 arch/powerpc/kernel/process.c | 101 +-
 arch/powerpc/platforms/powernv/ocxl.c |   4 +-
 drivers/misc/ocxl/context.c   |   5 +-
 drivers/misc/ocxl/file.c  |  78 ++
 drivers/misc/ocxl/link.c  |  38 -
 drivers/misc/ocxl/ocxl_internal.h |   1 +
 include/misc/ocxl.h   |   9 +++
 include/uapi/misc/ocxl.h  |  14 +
 13 files changed, 163 insertions(+), 105 deletions(-)

-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v5 6/7] ocxl: Add an IOCTL so userspace knows what OCXL features are available

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order for a userspace AFU driver to call the POWER9 specific
OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
make that call.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/file.c | 25 +
 include/uapi/misc/ocxl.h |  6 ++
 2 files changed, 31 insertions(+)

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index eb409a469f21..33ae46ce0a8a 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context 
*ctx,
 }
 #endif
 
+
+static long afu_ioctl_get_features(struct ocxl_context *ctx,
+   struct ocxl_ioctl_features __user *uarg)
+{
+   struct ocxl_ioctl_features arg;
+
+   memset(, 0, sizeof(arg));
+
+#ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_P9_TIDR))
+   arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
+#endif
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
+   x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
break;
 #endif
 
+   case OCXL_IOCTL_GET_FEATURES:
+   rc = afu_ioctl_get_features(ctx,
+   (struct ocxl_ioctl_features __user *) args);
+   break;
+
default:
rc = -EINVAL;
}
diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 561e6f0dfcb7..97937cfa3baa 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -55,6 +55,11 @@ struct ocxl_ioctl_p9_wait {
__u64 reserved3[3];
 };
 
+#define OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT 0x01
+struct ocxl_ioctl_features {
+   __u64 flags[4];
+};
+
 struct ocxl_ioctl_irq_fd {
__u64 irq_offset;
__s32 eventfd;
@@ -70,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
 #define OCXL_IOCTL_IRQ_SET_FD  _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
 #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct 
ocxl_ioctl_metadata)
 #define OCXL_IOCTL_ENABLE_P9_WAIT  _IOR(OCXL_MAGIC, 0x15, struct 
ocxl_ioctl_p9_wait)
+#define OCXL_IOCTL_GET_FEATURES _IOR(OCXL_MAGIC, 0x16, struct 
ocxl_ioctl_features)
 
 #endif /* _UAPI_MISC_OCXL_H */
-- 
2.17.0

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v5 2/7] powerpc: Use TIDR CPU feature to control TIDR allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Switch the use of TIDR on it's CPU feature, rather than assuming it
is available based on architecture.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/kernel/process.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1237f13fed51..3b00da47699b 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1154,7 +1154,7 @@ static inline void restore_sprs(struct thread_struct 
*old_thread,
mtspr(SPRN_TAR, new_thread->tar);
}
 
-   if (cpu_has_feature(CPU_FTR_ARCH_300) &&
+   if (cpu_has_feature(CPU_FTR_P9_TIDR) &&
old_thread->tidr != new_thread->tidr)
mtspr(SPRN_TIDR, new_thread->tidr);
 #endif
@@ -1570,7 +1570,7 @@ void clear_thread_tidr(struct task_struct *t)
if (!t->thread.tidr)
return;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR)) {
WARN_ON_ONCE(1);
return;
}
@@ -1593,7 +1593,7 @@ int set_thread_tidr(struct task_struct *t)
 {
int rc;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300))
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR))
return -EINVAL;
 
if (t != current)
-- 
2.17.0

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v4 3/7] powerpc: use task_pid_nr() for TID allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The current implementation of TID allocation, using a global IDR, may
result in an errant process starving the system of available TIDs.
Instead, use task_pid_nr(), as mentioned by the original author. The
scenario described which prevented it's use is not applicable, as
set_thread_tidr can only be called after the task struct has been
populated.

In the unlikely event that 2 threads share the TID and are waiting,
all potential outcomes have been determined safe.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/switch_to.h |   1 -
 arch/powerpc/kernel/process.c| 122 ---
 2 files changed, 28 insertions(+), 95 deletions(-)

diff --git a/arch/powerpc/include/asm/switch_to.h 
b/arch/powerpc/include/asm/switch_to.h
index be8c9fa23983..5b03d8a82409 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -94,6 +94,5 @@ static inline void clear_task_ebb(struct task_struct *t)
 extern int set_thread_uses_vas(void);
 
 extern int set_thread_tidr(struct task_struct *t);
-extern void clear_thread_tidr(struct task_struct *t);
 
 #endif /* _ASM_POWERPC_SWITCH_TO_H */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 3b00da47699b..c5b8e53acbae 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1496,103 +1496,41 @@ int set_thread_uses_vas(void)
 }
 
 #ifdef CONFIG_PPC64
-static DEFINE_SPINLOCK(vas_thread_id_lock);
-static DEFINE_IDA(vas_thread_ida);
-
-/*
- * We need to assign a unique thread id to each thread in a process.
+/**
+ * Assign a TIDR (thread ID) for task @t and set it in the thread
+ * structure. For now, we only support setting TIDR for 'current' task.
  *
- * This thread id, referred to as TIDR, and separate from the Linux's tgid,
- * is intended to be used to direct an ASB_Notify from the hardware to the
- * thread, when a suitable event occurs in the system.
+ * Since the TID value is a truncated form of it PID, it is possible
+ * (but unlikely) for 2 threads to have the same TID. In the unlikely event
+ * that 2 threads share the same TID and are waiting, one of the following
+ * cases will happen:
  *
- * One such event is a "paste" instruction in the context of Fast Thread
- * Wakeup (aka Core-to-core wake up in the Virtual Accelerator Switchboard
- * (VAS) in POWER9.
+ * 1. The correct thread is running, the wrong thread is not
+ * In this situation, the correct thread is woken and proceeds to pass it's
+ * condition check.
  *
- * To get a unique TIDR per process we could simply reuse task_pid_nr() but
- * the problem is that task_pid_nr() is not yet available copy_thread() is
- * called. Fixing that would require changing more intrusive arch-neutral
- * code in code path in copy_process()?.
+ * 2. Neither threads are running
+ * In this situation, neither thread will be woken. When scheduled, the waiting
+ * threads will execute either a wait, which will return immediately, followed
+ * by a condition check, which will pass for the correct thread and fail
+ * for the wrong thread, or they will execute the condition check immediately.
  *
- * Further, to assign unique TIDRs within each process, we need an atomic
- * field (or an IDR) in task_struct, which again intrudes into the arch-
- * neutral code. So try to assign globally unique TIDRs for now.
+ * 3. The wrong thread is running, the correct thread is not
+ * The wrong thread will be woken, but will fail it's condition check and
+ * re-execute wait. The correct thread, when scheduled, will execute either
+ * it's condition check (which will pass), or wait, which returns immediately
+ * when called the first time after the thread is scheduled, followed by it's
+ * condition check (which will pass).
  *
- * NOTE: TIDR 0 indicates that the thread does not need a TIDR value.
- *  For now, only threads that expect to be notified by the VAS
- *  hardware need a TIDR value and we assign values > 0 for those.
- */
-#define MAX_THREAD_CONTEXT ((1 << 16) - 1)
-static int assign_thread_tidr(void)
-{
-   int index;
-   int err;
-   unsigned long flags;
-
-again:
-   if (!ida_pre_get(_thread_ida, GFP_KERNEL))
-   return -ENOMEM;
-
-   spin_lock_irqsave(_thread_id_lock, flags);
-   err = ida_get_new_above(_thread_ida, 1, );
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-
-   if (err == -EAGAIN)
-   goto again;
-   else if (err)
-   return err;
-
-   if (index > MAX_THREAD_CONTEXT) {
-   spin_lock_irqsave(_thread_id_lock, flags);
-   ida_remove(_thread_ida, index);
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-   return -ENOMEM;
-   }
-
-   return index;
-}
-
-static void free_thread_tidr(int id)
-{
-   unsigned long flags;
-
-   spin_l

[PATCH v4 6/7] ocxl: Add an IOCTL so userspace knows what OCXL features are available

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order for a userspace AFU driver to call the POWER9 specific
OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
make that call.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/file.c | 25 +
 include/uapi/misc/ocxl.h |  4 
 2 files changed, 29 insertions(+)

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index eb409a469f21..33ae46ce0a8a 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context 
*ctx,
 }
 #endif
 
+
+static long afu_ioctl_get_features(struct ocxl_context *ctx,
+   struct ocxl_ioctl_features __user *uarg)
+{
+   struct ocxl_ioctl_features arg;
+
+   memset(, 0, sizeof(arg));
+
+#ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_P9_TIDR))
+   arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
+#endif
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
+   x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
break;
 #endif
 
+   case OCXL_IOCTL_GET_FEATURES:
+   rc = afu_ioctl_get_features(ctx,
+   (struct ocxl_ioctl_features __user *) args);
+   break;
+
default:
rc = -EINVAL;
}
diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 8d2748e69c84..bb80f294b429 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -55,6 +55,9 @@ struct ocxl_ioctl_p9_wait {
__u64 reserved3[3];
 };
 
+#define OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT 0x01
+struct ocxl_ioctl_features {
+   __u64 flags[4];
 };
 
 struct ocxl_ioctl_irq_fd {
@@ -72,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
 #define OCXL_IOCTL_IRQ_SET_FD  _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
 #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct 
ocxl_ioctl_metadata)
 #define OCXL_IOCTL_ENABLE_P9_WAIT  _IOR(OCXL_MAGIC, 0x15, struct 
ocxl_ioctl_p9_wait)
+#define OCXL_IOCTL_GET_FEATURES _IOR(OCXL_MAGIC, 0x16, struct 
ocxl_ioctl_platform)
 
 #endif /* _UAPI_MISC_OCXL_H */
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v4 7/7] ocxl: Document new OCXL IOCTLs

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 Documentation/accelerators/ocxl.rst | 11 +++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/accelerators/ocxl.rst 
b/Documentation/accelerators/ocxl.rst
index ddcc58d01cfb..14cefc020e2d 100644
--- a/Documentation/accelerators/ocxl.rst
+++ b/Documentation/accelerators/ocxl.rst
@@ -157,6 +157,17 @@ OCXL_IOCTL_GET_METADATA:
   Obtains configuration information from the card, such at the size of
   MMIO areas, the AFU version, and the PASID for the current context.
 
+OCXL_IOCTL_ENABLE_P9_WAIT:
+
+  Allows the AFU to wake a userspace thread executing 'wait'. Returns
+  information to userspace to allow it to configure the AFU. Note that
+  this is only available on POWER9.
+
+OCXL_IOCTL_GET_FEATURES:
+
+  Reports on which CPU features that affect OpenCAPI are usable from
+  userspace.
+
 
 mmap
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v4 4/7] ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The function removes the process element from NPU cache.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/pnv-ocxl.h   | 2 +-
 arch/powerpc/platforms/powernv/ocxl.c | 4 ++--
 drivers/misc/ocxl/link.c  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pnv-ocxl.h 
b/arch/powerpc/include/asm/pnv-ocxl.h
index f6945d3bc971..208b5503f4ed 100644
--- a/arch/powerpc/include/asm/pnv-ocxl.h
+++ b/arch/powerpc/include/asm/pnv-ocxl.h
@@ -28,7 +28,7 @@ extern int pnv_ocxl_map_xsl_regs(struct pci_dev *dev, void 
__iomem **dsisr,
 extern int pnv_ocxl_spa_setup(struct pci_dev *dev, void *spa_mem, int PE_mask,
void **platform_data);
 extern void pnv_ocxl_spa_release(void *platform_data);
-extern int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle);
+extern int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int 
pe_handle);
 
 extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
 extern void pnv_ocxl_free_xive_irq(u32 irq);
diff --git a/arch/powerpc/platforms/powernv/ocxl.c 
b/arch/powerpc/platforms/powernv/ocxl.c
index fa9b53af3c7b..8c65aacda9c8 100644
--- a/arch/powerpc/platforms/powernv/ocxl.c
+++ b/arch/powerpc/platforms/powernv/ocxl.c
@@ -475,7 +475,7 @@ void pnv_ocxl_spa_release(void *platform_data)
 }
 EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
 
-int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle)
+int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
 {
struct spa_data *data = (struct spa_data *) platform_data;
int rc;
@@ -483,7 +483,7 @@ int pnv_ocxl_spa_remove_pe(void *platform_data, int 
pe_handle)
rc = opal_npu_spa_clear_cache(data->phb_opal_id, data->bdfn, pe_handle);
return rc;
 }
-EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe);
+EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe_from_cache);
 
 int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr)
 {
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index f30790582dc0..656e8610eec2 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -599,7 +599,7 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
 * On powerpc, the entry needs to be cleared from the context
 * cache of the NPU.
 */
-   rc = pnv_ocxl_spa_remove_pe(link->platform_data, pe_handle);
+   rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
WARN_ON(rc);
 
pe_data = radix_tree_delete(>pe_tree, pe_handle);
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v4 5/7] ocxl: Expose the thread_id needed for wait on POWER9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order to successfully issue as_notify, an AFU needs to know the TID
to notify, which in turn means that this information should be
available in userspace so it can be communicated to the AFU.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/context.c   |  5 +++-
 drivers/misc/ocxl/file.c  | 53 +++
 drivers/misc/ocxl/link.c  | 36 ++
 drivers/misc/ocxl/ocxl_internal.h |  1 +
 include/misc/ocxl.h   |  9 +++
 include/uapi/misc/ocxl.h  | 10 
 6 files changed, 113 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 909e8807824a..95f74623113e 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct 
ocxl_afu *afu,
mutex_init(>xsl_error_lock);
mutex_init(>irq_lock);
idr_init(>irq_idr);
+   ctx->tidr = 0;
+
/*
 * Keep a reference on the AFU to make sure it's valid for the
 * duration of the life of the context
@@ -65,6 +67,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 {
int rc;
 
+   // Locks both status & tidr
mutex_lock(>status_mutex);
if (ctx->status != OPENED) {
rc = -EIO;
@@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
}
 
rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
-   current->mm->context.id, 0, amr, current->mm,
+   current->mm->context.id, ctx->tidr, amr, current->mm,
xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 038509e5d031..eb409a469f21 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -5,6 +5,8 @@
 #include 
 #include 
 #include 
+#include 
+#include 
 #include "ocxl_internal.h"
 
 
@@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct ocxl_context 
*ctx,
return 0;
 }
 
+#ifdef CONFIG_PPC64
+static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
+   struct ocxl_ioctl_p9_wait __user *uarg)
+{
+   struct ocxl_ioctl_p9_wait arg;
+
+   memset(, 0, sizeof(arg));
+
+   if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
+   enum ocxl_context_status status;
+
+   // Locks both status & tidr
+   mutex_lock(>status_mutex);
+   if (!ctx->tidr) {
+   if (set_thread_tidr(current))
+   return -ENOENT;
+
+   ctx->tidr = current->thread.tidr;
+   }
+
+   status = ctx->status;
+   mutex_unlock(>status_mutex);
+
+   if (status == ATTACHED) {
+   int rc;
+   struct link *link = ctx->afu->fn->link;
+
+   rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr);
+   if (rc)
+   return rc;
+   }
+
+   arg.thread_id = ctx->tidr;
+   } else
+   return -ENOENT;
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+#endif
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
+   x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -186,6 +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
(struct ocxl_ioctl_metadata __user *) args);
break;
 
+#ifdef CONFIG_PPC64
+   case OCXL_IOCTL_ENABLE_P9_WAIT:
+   rc = afu_ioctl_enable_p9_wait(ctx,
+   (struct ocxl_ioctl_p9_wait __user *) args);
+   break;
+#endif
+
default:
rc = -EINVAL;
}
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 656e8610eec2..88876ae8f330 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -544,6 +544,42 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 
pidr, u32 tidr,
 }
 EXPORT_SYMBOL_GPL(ocxl_link_add_pe);
 
+int ocxl_link_update_pe(void *link_handle

[PATCH v4 2/7] powerpc: Use TIDR CPU feature to control TIDR allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Switch the use of TIDR on it's CPU feature, rather than assuming it
is available based on architecture.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/kernel/process.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1237f13fed51..3b00da47699b 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1154,7 +1154,7 @@ static inline void restore_sprs(struct thread_struct 
*old_thread,
mtspr(SPRN_TAR, new_thread->tar);
}
 
-   if (cpu_has_feature(CPU_FTR_ARCH_300) &&
+   if (cpu_has_feature(CPU_FTR_P9_TIDR) &&
old_thread->tidr != new_thread->tidr)
mtspr(SPRN_TIDR, new_thread->tidr);
 #endif
@@ -1570,7 +1570,7 @@ void clear_thread_tidr(struct task_struct *t)
if (!t->thread.tidr)
return;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR)) {
WARN_ON_ONCE(1);
return;
}
@@ -1593,7 +1593,7 @@ int set_thread_tidr(struct task_struct *t)
 {
int rc;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300))
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR))
return -EINVAL;
 
if (t != current)
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v4 0/7] ocxl: Implement Power9 as_notify/wait for OpenCAPI

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The Power 9 as_notify/wait feature provides a lower latency way to
signal a thread that work is complete. This series enables the use of
this feature from OpenCAPI adapters, as well as addressing a potential
starvation issue when allocating thread IDs.

Changelog:
v4:
  Remove the "unique" statement from the set_thread_tidr function and
move the text explaining why it is safe from the commit message
to the function description
v3:
  Fix references to POWER9
  Remove stray whitespace edit from docs
  Add more details to commit message for "use task_pid_nr()"
  Retitle patch 6 to indicate OCXL rather than CPU features
v2:
  Rename get_platform IOCTL to get_features
  Move stray edit from patch 1 to patch 3

Alastair D'Silva (7):
  powerpc: Add TIDR CPU feature for POWER9
  powerpc: Use TIDR CPU feature to control TIDR allocation
  powerpc: use task_pid_nr() for TID allocation
  ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action
  ocxl: Expose the thread_id needed for wait on POWER9
  ocxl: Add an IOCTL so userspace knows what OCXL features are available
  ocxl: Document new OCXL IOCTLs

 Documentation/accelerators/ocxl.rst   |  11 
 arch/powerpc/include/asm/cputable.h   |   3 +-
 arch/powerpc/include/asm/pnv-ocxl.h   |   2 +-
 arch/powerpc/include/asm/switch_to.h  |   1 -
 arch/powerpc/kernel/dt_cpu_ftrs.c |   1 +
 arch/powerpc/kernel/process.c | 101 +-
 arch/powerpc/platforms/powernv/ocxl.c |   4 +-
 drivers/misc/ocxl/context.c   |   5 +-
 drivers/misc/ocxl/file.c  |  78 ++
 drivers/misc/ocxl/link.c  |  38 -
 drivers/misc/ocxl/ocxl_internal.h |   1 +
 include/misc/ocxl.h   |   9 +++
 include/uapi/misc/ocxl.h  |  14 +
 13 files changed, 163 insertions(+), 105 deletions(-)

-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v4 1/7] powerpc: Add TIDR CPU feature for POWER9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

This patch adds a CPU feature bit to show whether the CPU has
the TIDR register available, enabling as_notify/wait in userspace.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/cputable.h | 3 ++-
 arch/powerpc/kernel/dt_cpu_ftrs.c   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/cputable.h 
b/arch/powerpc/include/asm/cputable.h
index 4e332f3531c5..54c4cbbe57b4 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -215,6 +215,7 @@ static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_P9_TM_HV_ASSIST
LONG_ASM_CONST(0x1000)
 #define CPU_FTR_P9_TM_XER_SO_BUG   LONG_ASM_CONST(0x2000)
 #define CPU_FTR_P9_TLBIE_BUG   LONG_ASM_CONST(0x4000)
+#define CPU_FTR_P9_TIDR
LONG_ASM_CONST(0x8000)
 
 #ifndef __ASSEMBLY__
 
@@ -462,7 +463,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY | \
-   CPU_FTR_P9_TLBIE_BUG)
+   CPU_FTR_P9_TLBIE_BUG | CPU_FTR_P9_TIDR)
 #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \
 (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 11a3a4fed3fb..10f8b7f55637 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -722,6 +722,7 @@ static __init void cpufeatures_cpu_quirks(void)
if ((version & 0x) == 0x004e) {
cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+   cur_cpu_spec->cpu_features |= CPU_FTR_P9_TIDR;
}
 }
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 2/7] powerpc: Use TIDR CPU feature to control TIDR allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Switch the use of TIDR on it's CPU feature, rather than assuming it
is available based on architecture.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/kernel/process.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1237f13fed51..3b00da47699b 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1154,7 +1154,7 @@ static inline void restore_sprs(struct thread_struct 
*old_thread,
mtspr(SPRN_TAR, new_thread->tar);
}
 
-   if (cpu_has_feature(CPU_FTR_ARCH_300) &&
+   if (cpu_has_feature(CPU_FTR_P9_TIDR) &&
old_thread->tidr != new_thread->tidr)
mtspr(SPRN_TIDR, new_thread->tidr);
 #endif
@@ -1570,7 +1570,7 @@ void clear_thread_tidr(struct task_struct *t)
if (!t->thread.tidr)
return;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR)) {
WARN_ON_ONCE(1);
return;
}
@@ -1593,7 +1593,7 @@ int set_thread_tidr(struct task_struct *t)
 {
int rc;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300))
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR))
return -EINVAL;
 
if (t != current)
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 1/7] powerpc: Add TIDR CPU feature for POWER9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

This patch adds a CPU feature bit to show whether the CPU has
the TIDR register available, enabling as_notify/wait in userspace.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/cputable.h | 3 ++-
 arch/powerpc/kernel/dt_cpu_ftrs.c   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/cputable.h 
b/arch/powerpc/include/asm/cputable.h
index 4e332f3531c5..54c4cbbe57b4 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -215,6 +215,7 @@ static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_P9_TM_HV_ASSIST
LONG_ASM_CONST(0x1000)
 #define CPU_FTR_P9_TM_XER_SO_BUG   LONG_ASM_CONST(0x2000)
 #define CPU_FTR_P9_TLBIE_BUG   LONG_ASM_CONST(0x4000)
+#define CPU_FTR_P9_TIDR
LONG_ASM_CONST(0x8000)
 
 #ifndef __ASSEMBLY__
 
@@ -462,7 +463,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY | \
-   CPU_FTR_P9_TLBIE_BUG)
+   CPU_FTR_P9_TLBIE_BUG | CPU_FTR_P9_TIDR)
 #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \
 (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 11a3a4fed3fb..10f8b7f55637 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -722,6 +722,7 @@ static __init void cpufeatures_cpu_quirks(void)
if ((version & 0x) == 0x004e) {
cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+   cur_cpu_spec->cpu_features |= CPU_FTR_P9_TIDR;
}
 }
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 7/7] ocxl: Document new OCXL IOCTLs

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 Documentation/accelerators/ocxl.rst | 11 +++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/accelerators/ocxl.rst 
b/Documentation/accelerators/ocxl.rst
index ddcc58d01cfb..14cefc020e2d 100644
--- a/Documentation/accelerators/ocxl.rst
+++ b/Documentation/accelerators/ocxl.rst
@@ -157,6 +157,17 @@ OCXL_IOCTL_GET_METADATA:
   Obtains configuration information from the card, such at the size of
   MMIO areas, the AFU version, and the PASID for the current context.
 
+OCXL_IOCTL_ENABLE_P9_WAIT:
+
+  Allows the AFU to wake a userspace thread executing 'wait'. Returns
+  information to userspace to allow it to configure the AFU. Note that
+  this is only available on POWER9.
+
+OCXL_IOCTL_GET_FEATURES:
+
+  Reports on which CPU features that affect OpenCAPI are usable from
+  userspace.
+
 
 mmap
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 0/7] ocxl: Implement Power9 as_notify/wait for OpenCAPI

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The Power 9 as_notify/wait feature provides a lower latency way to
signal a thread that work is complete. This series enables the use of
this feature from OpenCAPI adapters, as well as addressing a potential
starvation issue when allocating thread IDs.

Changelog:
v3:
  Fix references to POWER9
  Remove stray whitespace edit from docs
  Add more details to commit message for "use task_pid_nr()"
  Retitle patch 6 to indicate OCXL rather than CPU features
v2:
  Rename get_platform IOCTL to get_features
  Move stray edit from patch 1 to patch 3

Alastair D'Silva (7):
  powerpc: Add TIDR CPU feature for POWER9
  powerpc: Use TIDR CPU feature to control TIDR allocation
  powerpc: use task_pid_nr() for TID allocation
  ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action
  ocxl: Expose the thread_id needed for wait on POWER9
  ocxl: Add an IOCTL so userspace knows what OCXL features are available
  ocxl: Document new OCXL IOCTLs

 Documentation/accelerators/ocxl.rst   |  11 
 arch/powerpc/include/asm/cputable.h   |   3 +-
 arch/powerpc/include/asm/pnv-ocxl.h   |   2 +-
 arch/powerpc/include/asm/switch_to.h  |   1 -
 arch/powerpc/kernel/dt_cpu_ftrs.c |   1 +
 arch/powerpc/kernel/process.c | 101 +-
 arch/powerpc/platforms/powernv/ocxl.c |   4 +-
 drivers/misc/ocxl/context.c   |   5 +-
 drivers/misc/ocxl/file.c  |  78 ++
 drivers/misc/ocxl/link.c  |  38 -
 drivers/misc/ocxl/ocxl_internal.h |   1 +
 include/misc/ocxl.h   |   9 +++
 include/uapi/misc/ocxl.h  |  14 +
 13 files changed, 163 insertions(+), 105 deletions(-)

-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 4/7] ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The function removes the process element from NPU cache.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/pnv-ocxl.h   | 2 +-
 arch/powerpc/platforms/powernv/ocxl.c | 4 ++--
 drivers/misc/ocxl/link.c  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pnv-ocxl.h 
b/arch/powerpc/include/asm/pnv-ocxl.h
index f6945d3bc971..208b5503f4ed 100644
--- a/arch/powerpc/include/asm/pnv-ocxl.h
+++ b/arch/powerpc/include/asm/pnv-ocxl.h
@@ -28,7 +28,7 @@ extern int pnv_ocxl_map_xsl_regs(struct pci_dev *dev, void 
__iomem **dsisr,
 extern int pnv_ocxl_spa_setup(struct pci_dev *dev, void *spa_mem, int PE_mask,
void **platform_data);
 extern void pnv_ocxl_spa_release(void *platform_data);
-extern int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle);
+extern int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int 
pe_handle);
 
 extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
 extern void pnv_ocxl_free_xive_irq(u32 irq);
diff --git a/arch/powerpc/platforms/powernv/ocxl.c 
b/arch/powerpc/platforms/powernv/ocxl.c
index fa9b53af3c7b..8c65aacda9c8 100644
--- a/arch/powerpc/platforms/powernv/ocxl.c
+++ b/arch/powerpc/platforms/powernv/ocxl.c
@@ -475,7 +475,7 @@ void pnv_ocxl_spa_release(void *platform_data)
 }
 EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
 
-int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle)
+int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
 {
struct spa_data *data = (struct spa_data *) platform_data;
int rc;
@@ -483,7 +483,7 @@ int pnv_ocxl_spa_remove_pe(void *platform_data, int 
pe_handle)
rc = opal_npu_spa_clear_cache(data->phb_opal_id, data->bdfn, pe_handle);
return rc;
 }
-EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe);
+EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe_from_cache);
 
 int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr)
 {
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index f30790582dc0..656e8610eec2 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -599,7 +599,7 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
 * On powerpc, the entry needs to be cleared from the context
 * cache of the NPU.
 */
-   rc = pnv_ocxl_spa_remove_pe(link->platform_data, pe_handle);
+   rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
WARN_ON(rc);
 
pe_data = radix_tree_delete(>pe_tree, pe_handle);
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 6/7] ocxl: Add an IOCTL so userspace knows what OCXL features are available

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order for a userspace AFU driver to call the POWER9 specific
OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
make that call.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/file.c | 25 +
 include/uapi/misc/ocxl.h |  4 
 2 files changed, 29 insertions(+)

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index eb409a469f21..33ae46ce0a8a 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context 
*ctx,
 }
 #endif
 
+
+static long afu_ioctl_get_features(struct ocxl_context *ctx,
+   struct ocxl_ioctl_features __user *uarg)
+{
+   struct ocxl_ioctl_features arg;
+
+   memset(, 0, sizeof(arg));
+
+#ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_P9_TIDR))
+   arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
+#endif
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
+   x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
break;
 #endif
 
+   case OCXL_IOCTL_GET_FEATURES:
+   rc = afu_ioctl_get_features(ctx,
+   (struct ocxl_ioctl_features __user *) args);
+   break;
+
default:
rc = -EINVAL;
}
diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 8d2748e69c84..bb80f294b429 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -55,6 +55,9 @@ struct ocxl_ioctl_p9_wait {
__u64 reserved3[3];
 };
 
+#define OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT 0x01
+struct ocxl_ioctl_features {
+   __u64 flags[4];
 };
 
 struct ocxl_ioctl_irq_fd {
@@ -72,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
 #define OCXL_IOCTL_IRQ_SET_FD  _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
 #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct 
ocxl_ioctl_metadata)
 #define OCXL_IOCTL_ENABLE_P9_WAIT  _IOR(OCXL_MAGIC, 0x15, struct 
ocxl_ioctl_p9_wait)
+#define OCXL_IOCTL_GET_FEATURES _IOR(OCXL_MAGIC, 0x16, struct 
ocxl_ioctl_platform)
 
 #endif /* _UAPI_MISC_OCXL_H */
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 5/7] ocxl: Expose the thread_id needed for wait on POWER9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order to successfully issue as_notify, an AFU needs to know the TID
to notify, which in turn means that this information should be
available in userspace so it can be communicated to the AFU.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/context.c   |  5 +++-
 drivers/misc/ocxl/file.c  | 53 +++
 drivers/misc/ocxl/link.c  | 36 ++
 drivers/misc/ocxl/ocxl_internal.h |  1 +
 include/misc/ocxl.h   |  9 +++
 include/uapi/misc/ocxl.h  | 10 
 6 files changed, 113 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 909e8807824a..95f74623113e 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct 
ocxl_afu *afu,
mutex_init(>xsl_error_lock);
mutex_init(>irq_lock);
idr_init(>irq_idr);
+   ctx->tidr = 0;
+
/*
 * Keep a reference on the AFU to make sure it's valid for the
 * duration of the life of the context
@@ -65,6 +67,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 {
int rc;
 
+   // Locks both status & tidr
mutex_lock(>status_mutex);
if (ctx->status != OPENED) {
rc = -EIO;
@@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
}
 
rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
-   current->mm->context.id, 0, amr, current->mm,
+   current->mm->context.id, ctx->tidr, amr, current->mm,
xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 038509e5d031..eb409a469f21 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -5,6 +5,8 @@
 #include 
 #include 
 #include 
+#include 
+#include 
 #include "ocxl_internal.h"
 
 
@@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct ocxl_context 
*ctx,
return 0;
 }
 
+#ifdef CONFIG_PPC64
+static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
+   struct ocxl_ioctl_p9_wait __user *uarg)
+{
+   struct ocxl_ioctl_p9_wait arg;
+
+   memset(, 0, sizeof(arg));
+
+   if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
+   enum ocxl_context_status status;
+
+   // Locks both status & tidr
+   mutex_lock(>status_mutex);
+   if (!ctx->tidr) {
+   if (set_thread_tidr(current))
+   return -ENOENT;
+
+   ctx->tidr = current->thread.tidr;
+   }
+
+   status = ctx->status;
+   mutex_unlock(>status_mutex);
+
+   if (status == ATTACHED) {
+   int rc;
+   struct link *link = ctx->afu->fn->link;
+
+   rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr);
+   if (rc)
+   return rc;
+   }
+
+   arg.thread_id = ctx->tidr;
+   } else
+   return -ENOENT;
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+#endif
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
+   x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -186,6 +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
(struct ocxl_ioctl_metadata __user *) args);
break;
 
+#ifdef CONFIG_PPC64
+   case OCXL_IOCTL_ENABLE_P9_WAIT:
+   rc = afu_ioctl_enable_p9_wait(ctx,
+   (struct ocxl_ioctl_p9_wait __user *) args);
+   break;
+#endif
+
default:
rc = -EINVAL;
}
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 656e8610eec2..88876ae8f330 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -544,6 +544,42 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 
pidr, u32 tidr,
 }
 EXPORT_SYMBOL_GPL(ocxl_link_add_pe);
 
+int ocxl_link_update_pe(void *link_handle

Re: [PATCH v2 6/7] ocxl: Add an IOCTL so userspace knows what CPU features are available

[Alastair D'Silva]

On Tue, 2018-05-08 at 13:50 +1000, Nicholas Piggin wrote:
> On Tue, 08 May 2018 10:41:55 +1000
> "Alastair D'Silva" <alast...@au1.ibm.com> wrote:
> 
> > On Mon, 2018-05-07 at 20:14 +0200, Frederic Barrat wrote:
> > > 
> > > Le 18/04/2018 à 03:08, Alastair D'Silva a écrit :  
> > > > From: Alastair D'Silva <alast...@d-silva.org>
> > > > 
> > > > In order for a userspace AFU driver to call the Power9 specific
> > > > OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can
> > > > actually
> > > > make that call.
> > > > 
> > > > Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
> > > > ---
> > > >   Documentation/accelerators/ocxl.rst |  1 -
> > > >   drivers/misc/ocxl/file.c| 25
> > > > +
> > > >   include/uapi/misc/ocxl.h|  4 
> > > >   3 files changed, 29 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/Documentation/accelerators/ocxl.rst
> > > > b/Documentation/accelerators/ocxl.rst
> > > > index ddcc58d01cfb..7904adcc07fd 100644
> > > > --- a/Documentation/accelerators/ocxl.rst
> > > > +++ b/Documentation/accelerators/ocxl.rst
> > > > @@ -157,7 +157,6 @@ OCXL_IOCTL_GET_METADATA:
> > > > Obtains configuration information from the card, such at
> > > > the
> > > > size of
> > > > MMIO areas, the AFU version, and the PASID for the current
> > > > context.
> > > > 
> > > > -  
> > > 
> > > 
> > > Intended?
> > > 
> > > Other than that,
> > > Acked-by: Frederic Barrat <fbar...@linux.vnet.ibm.com>
> > >   
> > 
> > Nope, I'll fix that, thanks.
> > 
> 
> Just to be clear, this is for OCXL features. I would just make that
> explicit in the title (s/CPU/OCXL).
> 
> Thanks,
> Nick
> 

OK, sounds reasonable.

-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v2 1/7] powerpc: Add TIDR CPU feature for Power9

[Alastair D'Silva]

On Mon, 2018-05-07 at 19:17 +0200, Frederic Barrat wrote:
> 
> Le 18/04/2018 à 03:08, Alastair D'Silva a écrit :
> > From: Alastair D'Silva <alast...@d-silva.org>
> > 
> > This patch adds a CPU feature bit to show whether the CPU has
> > the TIDR register available, enabling as_notify/wait in userspace.
> > 
> > Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
> > ---
> >   arch/powerpc/include/asm/cputable.h | 3 ++-
> >   arch/powerpc/kernel/dt_cpu_ftrs.c   | 1 +
> >   2 files changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/powerpc/include/asm/cputable.h
> > b/arch/powerpc/include/asm/cputable.h
> > index 4e332f3531c5..54c4cbbe57b4 100644
> > --- a/arch/powerpc/include/asm/cputable.h
> > +++ b/arch/powerpc/include/asm/cputable.h
> > @@ -215,6 +215,7 @@ static inline void cpu_feature_keys_init(void)
> > { }
> >   #define CPU_FTR_P9_TM_HV_ASSIST   LONG_ASM_CONST(0x0
> > 0001000)
> >   #define CPU_FTR_P9_TM_XER_SO_BUG  LONG_ASM_CONST(0x2000
> > )
> >   #define CPU_FTR_P9_TLBIE_BUG  LONG_ASM_CONST(0x
> > 4000)
> > +#define CPU_FTR_P9_TIDRLONG_ASM_CONST(0x00
> > 008000)
> > 
> >   #ifndef __ASSEMBLY__
> > 
> > @@ -462,7 +463,7 @@ static inline void cpu_feature_keys_init(void)
> > { }
> > CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
> > CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S |
> > \
> > CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY | \
> > -   CPU_FTR_P9_TLBIE_BUG)
> > +   CPU_FTR_P9_TLBIE_BUG | CPU_FTR_P9_TIDR)
> >   #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 |
> > CPU_FTR_POWER9_DD1) & \
> >  (~CPU_FTR_SAO))
> >   #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
> > diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c
> > b/arch/powerpc/kernel/dt_cpu_ftrs.c
> > index 11a3a4fed3fb..10f8b7f55637 100644
> > --- a/arch/powerpc/kernel/dt_cpu_ftrs.c
> > +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
> > @@ -722,6 +722,7 @@ static __init void cpufeatures_cpu_quirks(void)
> > if ((version & 0x) == 0x004e) {
> > cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
> > cur_cpu_spec->cpu_features |=
> > CPU_FTR_P9_TLBIE_BUG; > +   cur_cpu_spec->cpu_features 
> > |= CPU_FTR_P9_TIDR;
> 
> 
> Isn't it redundant with adding the flag to CPU_FTRS_POWER9?
> 
>Fred
> 

No, cpu_features is populated from device tree, not from
CPU_FTRS_POWER9. Since TIDR will not be explicitly requested in the
device tree, we need to handle it in quirks.

-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v2 6/7] ocxl: Add an IOCTL so userspace knows what CPU features are available

[Alastair D'Silva]

On Mon, 2018-05-07 at 20:14 +0200, Frederic Barrat wrote:
> 
> Le 18/04/2018 à 03:08, Alastair D'Silva a écrit :
> > From: Alastair D'Silva <alast...@d-silva.org>
> > 
> > In order for a userspace AFU driver to call the Power9 specific
> > OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
> > make that call.
> > 
> > Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
> > ---
> >   Documentation/accelerators/ocxl.rst |  1 -
> >   drivers/misc/ocxl/file.c| 25
> > +
> >   include/uapi/misc/ocxl.h|  4 
> >   3 files changed, 29 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/accelerators/ocxl.rst
> > b/Documentation/accelerators/ocxl.rst
> > index ddcc58d01cfb..7904adcc07fd 100644
> > --- a/Documentation/accelerators/ocxl.rst
> > +++ b/Documentation/accelerators/ocxl.rst
> > @@ -157,7 +157,6 @@ OCXL_IOCTL_GET_METADATA:
> > Obtains configuration information from the card, such at the
> > size of
> > MMIO areas, the AFU version, and the PASID for the current
> > context.
> > 
> > -
> 
> 
> Intended?
> 
> Other than that,
> Acked-by: Frederic Barrat <fbar...@linux.vnet.ibm.com>
> 

Nope, I'll fix that, thanks.

-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australiamob: 0423 762 819

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v2 3/7] powerpc: use task_pid_nr() for TID allocation

[Alastair D'Silva]

On Mon, 2018-05-07 at 19:37 +0200, Frederic Barrat wrote:
> 
> Le 18/04/2018 à 03:08, Alastair D'Silva a écrit :
> > From: Alastair D'Silva <alast...@d-silva.org>
> > 
> > The current implementation of TID allocation, using a global IDR,
> > may
> > result in an errant process starving the system of available TIDs.
> > Instead, use task_pid_nr(), as mentioned by the original author.
> > The
> > scenario described which prevented it's use is not applicable, as
> > set_thread_tidr can only be called after the task struct has been
> > populated.
> 
> 
> Here is how I understand what's going to happen if 2 threads are
> using 
> the same TIDR value, which is possible with this patch (if unlikely):
> 
> 1. waking up the wrong thread is not really a problem, as threads
> have 
> to handle spurious wake up from the 'wait' instruction anyway, and
> must 
> be using some other condition to know when to loop around the 'wait' 
> instruction.
> 
> 2. missing the right thread: if the wrong thread is on a CPU, and a 
> wake_host_thread/as_notify is sent, the core will see a matching
> thread 
> and will accept the command. The (open)capi adapter won't send an 
> interrupt. The wrong thread is awaken, which is not a problem as 
> discussed above. As the right thread to notify is not running, no
> harm 
> is done either: as soon as the thread runs, it's supposed to check
> its 
> condition (which will be met) or call 'wait', but 'wait' immediately 
> returns when called the first time after a thread is scheduled.
> 
> So I believe we are ok. But I think it requires a huge comment with
> the 
> above (at the minimum) :-)
> 
> With a comment:
> Reviewed-by: Frederic Barrat <fbar...@linux.vnet.ibm.com>
> 
>Fred
> 

Good point, I'll add this in the next revision.


-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australiamob: 0423 762 819

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 7/7] ocxl: Document new OCXL IOCTLs

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 Documentation/accelerators/ocxl.rst | 11 +++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/accelerators/ocxl.rst 
b/Documentation/accelerators/ocxl.rst
index 7904adcc07fd..3b8d3b99795c 100644
--- a/Documentation/accelerators/ocxl.rst
+++ b/Documentation/accelerators/ocxl.rst
@@ -157,6 +157,17 @@ OCXL_IOCTL_GET_METADATA:
   Obtains configuration information from the card, such at the size of
   MMIO areas, the AFU version, and the PASID for the current context.
 
+OCXL_IOCTL_ENABLE_P9_WAIT:
+
+  Allows the AFU to wake a userspace thread executing 'wait'. Returns
+  information to userspace to allow it to configure the AFU. Note that
+  this is only available on Power 9.
+
+OCXL_IOCTL_GET_FEATURES:
+
+  Reports on which CPU features that affect OpenCAPI are usable from
+  userspace.
+
 mmap
 
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 6/7] ocxl: Add an IOCTL so userspace knows what CPU features are available

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order for a userspace AFU driver to call the Power9 specific
OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
make that call.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 Documentation/accelerators/ocxl.rst |  1 -
 drivers/misc/ocxl/file.c| 25 +
 include/uapi/misc/ocxl.h|  4 
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/Documentation/accelerators/ocxl.rst 
b/Documentation/accelerators/ocxl.rst
index ddcc58d01cfb..7904adcc07fd 100644
--- a/Documentation/accelerators/ocxl.rst
+++ b/Documentation/accelerators/ocxl.rst
@@ -157,7 +157,6 @@ OCXL_IOCTL_GET_METADATA:
   Obtains configuration information from the card, such at the size of
   MMIO areas, the AFU version, and the PASID for the current context.
 
-
 mmap
 
 
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index eb409a469f21..33ae46ce0a8a 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context 
*ctx,
 }
 #endif
 
+
+static long afu_ioctl_get_features(struct ocxl_context *ctx,
+   struct ocxl_ioctl_features __user *uarg)
+{
+   struct ocxl_ioctl_features arg;
+
+   memset(, 0, sizeof(arg));
+
+#ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_P9_TIDR))
+   arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
+#endif
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
+   x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
break;
 #endif
 
+   case OCXL_IOCTL_GET_FEATURES:
+   rc = afu_ioctl_get_features(ctx,
+   (struct ocxl_ioctl_features __user *) args);
+   break;
+
default:
rc = -EINVAL;
}
diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 8d2748e69c84..bb80f294b429 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -55,6 +55,9 @@ struct ocxl_ioctl_p9_wait {
__u64 reserved3[3];
 };
 
+#define OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT 0x01
+struct ocxl_ioctl_features {
+   __u64 flags[4];
 };
 
 struct ocxl_ioctl_irq_fd {
@@ -72,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
 #define OCXL_IOCTL_IRQ_SET_FD  _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
 #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct 
ocxl_ioctl_metadata)
 #define OCXL_IOCTL_ENABLE_P9_WAIT  _IOR(OCXL_MAGIC, 0x15, struct 
ocxl_ioctl_p9_wait)
+#define OCXL_IOCTL_GET_FEATURES _IOR(OCXL_MAGIC, 0x16, struct 
ocxl_ioctl_platform)
 
 #endif /* _UAPI_MISC_OCXL_H */
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 5/7] ocxl: Expose the thread_id needed for wait on p9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order to successfully issue as_notify, an AFU needs to know the TID
to notify, which in turn means that this information should be
available in userspace so it can be communicated to the AFU.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/context.c   |  5 +++-
 drivers/misc/ocxl/file.c  | 53 +++
 drivers/misc/ocxl/link.c  | 36 ++
 drivers/misc/ocxl/ocxl_internal.h |  1 +
 include/misc/ocxl.h   |  9 +++
 include/uapi/misc/ocxl.h  | 10 
 6 files changed, 113 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 909e8807824a..95f74623113e 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct 
ocxl_afu *afu,
mutex_init(>xsl_error_lock);
mutex_init(>irq_lock);
idr_init(>irq_idr);
+   ctx->tidr = 0;
+
/*
 * Keep a reference on the AFU to make sure it's valid for the
 * duration of the life of the context
@@ -65,6 +67,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 {
int rc;
 
+   // Locks both status & tidr
mutex_lock(>status_mutex);
if (ctx->status != OPENED) {
rc = -EIO;
@@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
}
 
rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
-   current->mm->context.id, 0, amr, current->mm,
+   current->mm->context.id, ctx->tidr, amr, current->mm,
xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 038509e5d031..eb409a469f21 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -5,6 +5,8 @@
 #include 
 #include 
 #include 
+#include 
+#include 
 #include "ocxl_internal.h"
 
 
@@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct ocxl_context 
*ctx,
return 0;
 }
 
+#ifdef CONFIG_PPC64
+static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
+   struct ocxl_ioctl_p9_wait __user *uarg)
+{
+   struct ocxl_ioctl_p9_wait arg;
+
+   memset(, 0, sizeof(arg));
+
+   if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
+   enum ocxl_context_status status;
+
+   // Locks both status & tidr
+   mutex_lock(>status_mutex);
+   if (!ctx->tidr) {
+   if (set_thread_tidr(current))
+   return -ENOENT;
+
+   ctx->tidr = current->thread.tidr;
+   }
+
+   status = ctx->status;
+   mutex_unlock(>status_mutex);
+
+   if (status == ATTACHED) {
+   int rc;
+   struct link *link = ctx->afu->fn->link;
+
+   rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr);
+   if (rc)
+   return rc;
+   }
+
+   arg.thread_id = ctx->tidr;
+   } else
+   return -ENOENT;
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+#endif
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
+   x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -186,6 +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
(struct ocxl_ioctl_metadata __user *) args);
break;
 
+#ifdef CONFIG_PPC64
+   case OCXL_IOCTL_ENABLE_P9_WAIT:
+   rc = afu_ioctl_enable_p9_wait(ctx,
+   (struct ocxl_ioctl_p9_wait __user *) args);
+   break;
+#endif
+
default:
rc = -EINVAL;
}
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 656e8610eec2..88876ae8f330 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -544,6 +544,42 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 
pidr, u32 tidr,
 }
 EXPORT_SYMBOL_GPL(ocxl_link_add_pe);
 
+int ocxl_link_update_pe(void *link_handle

[PATCH v2 2/7] powerpc: Use TIDR CPU feature to control TIDR allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Switch the use of TIDR on it's CPU feature, rather than assuming it
is available based on architecture.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/kernel/process.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1237f13fed51..3b00da47699b 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1154,7 +1154,7 @@ static inline void restore_sprs(struct thread_struct 
*old_thread,
mtspr(SPRN_TAR, new_thread->tar);
}
 
-   if (cpu_has_feature(CPU_FTR_ARCH_300) &&
+   if (cpu_has_feature(CPU_FTR_P9_TIDR) &&
old_thread->tidr != new_thread->tidr)
mtspr(SPRN_TIDR, new_thread->tidr);
 #endif
@@ -1570,7 +1570,7 @@ void clear_thread_tidr(struct task_struct *t)
if (!t->thread.tidr)
return;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR)) {
WARN_ON_ONCE(1);
return;
}
@@ -1593,7 +1593,7 @@ int set_thread_tidr(struct task_struct *t)
 {
int rc;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300))
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR))
return -EINVAL;
 
if (t != current)
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 1/7] powerpc: Add TIDR CPU feature for Power9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

This patch adds a CPU feature bit to show whether the CPU has
the TIDR register available, enabling as_notify/wait in userspace.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/cputable.h | 3 ++-
 arch/powerpc/kernel/dt_cpu_ftrs.c   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/cputable.h 
b/arch/powerpc/include/asm/cputable.h
index 4e332f3531c5..54c4cbbe57b4 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -215,6 +215,7 @@ static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_P9_TM_HV_ASSIST
LONG_ASM_CONST(0x1000)
 #define CPU_FTR_P9_TM_XER_SO_BUG   LONG_ASM_CONST(0x2000)
 #define CPU_FTR_P9_TLBIE_BUG   LONG_ASM_CONST(0x4000)
+#define CPU_FTR_P9_TIDR
LONG_ASM_CONST(0x8000)
 
 #ifndef __ASSEMBLY__
 
@@ -462,7 +463,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY | \
-   CPU_FTR_P9_TLBIE_BUG)
+   CPU_FTR_P9_TLBIE_BUG | CPU_FTR_P9_TIDR)
 #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \
 (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 11a3a4fed3fb..10f8b7f55637 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -722,6 +722,7 @@ static __init void cpufeatures_cpu_quirks(void)
if ((version & 0x) == 0x004e) {
cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+   cur_cpu_spec->cpu_features |= CPU_FTR_P9_TIDR;
}
 }
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 4/7] ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The function removes the process element from NPU cache.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/pnv-ocxl.h   | 2 +-
 arch/powerpc/platforms/powernv/ocxl.c | 4 ++--
 drivers/misc/ocxl/link.c  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pnv-ocxl.h 
b/arch/powerpc/include/asm/pnv-ocxl.h
index f6945d3bc971..208b5503f4ed 100644
--- a/arch/powerpc/include/asm/pnv-ocxl.h
+++ b/arch/powerpc/include/asm/pnv-ocxl.h
@@ -28,7 +28,7 @@ extern int pnv_ocxl_map_xsl_regs(struct pci_dev *dev, void 
__iomem **dsisr,
 extern int pnv_ocxl_spa_setup(struct pci_dev *dev, void *spa_mem, int PE_mask,
void **platform_data);
 extern void pnv_ocxl_spa_release(void *platform_data);
-extern int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle);
+extern int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int 
pe_handle);
 
 extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
 extern void pnv_ocxl_free_xive_irq(u32 irq);
diff --git a/arch/powerpc/platforms/powernv/ocxl.c 
b/arch/powerpc/platforms/powernv/ocxl.c
index fa9b53af3c7b..8c65aacda9c8 100644
--- a/arch/powerpc/platforms/powernv/ocxl.c
+++ b/arch/powerpc/platforms/powernv/ocxl.c
@@ -475,7 +475,7 @@ void pnv_ocxl_spa_release(void *platform_data)
 }
 EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
 
-int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle)
+int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
 {
struct spa_data *data = (struct spa_data *) platform_data;
int rc;
@@ -483,7 +483,7 @@ int pnv_ocxl_spa_remove_pe(void *platform_data, int 
pe_handle)
rc = opal_npu_spa_clear_cache(data->phb_opal_id, data->bdfn, pe_handle);
return rc;
 }
-EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe);
+EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe_from_cache);
 
 int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr)
 {
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index f30790582dc0..656e8610eec2 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -599,7 +599,7 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
 * On powerpc, the entry needs to be cleared from the context
 * cache of the NPU.
 */
-   rc = pnv_ocxl_spa_remove_pe(link->platform_data, pe_handle);
+   rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
WARN_ON(rc);
 
pe_data = radix_tree_delete(>pe_tree, pe_handle);
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 0/7] ocxl: Implement Power9 as_notify/wait for OpenCAPI

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The Power 9 as_notify/wait feature provides a lower latency way to
signal a thread that work is complete. This series enables the use of
this feature from OpenCAPI adapters, as well as addressing a potential
starvation issue when allocating thread IDs.

Changelog:
v2:
  Rename get_platform IOCTL to get_features
  Move stray edit from patch 1 to patch 3

Alastair D'Silva (7):
  powerpc: Add TIDR CPU feature for Power9
  powerpc: Use TIDR CPU feature to control TIDR allocation
  powerpc: use task_pid_nr() for TID allocation
  ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action
  ocxl: Expose the thread_id needed for wait on p9
  ocxl: Add an IOCTL so userspace knows what CPU features are available
  ocxl: Document new OCXL IOCTLs

 Documentation/accelerators/ocxl.rst   |  10 
 arch/powerpc/include/asm/cputable.h   |   3 +-
 arch/powerpc/include/asm/pnv-ocxl.h   |   2 +-
 arch/powerpc/include/asm/switch_to.h  |   1 -
 arch/powerpc/kernel/dt_cpu_ftrs.c |   1 +
 arch/powerpc/kernel/process.c | 101 +-
 arch/powerpc/platforms/powernv/ocxl.c |   4 +-
 drivers/misc/ocxl/context.c   |   5 +-
 drivers/misc/ocxl/file.c  |  78 ++
 drivers/misc/ocxl/link.c  |  38 -
 drivers/misc/ocxl/ocxl_internal.h |   1 +
 include/misc/ocxl.h   |   9 +++
 include/uapi/misc/ocxl.h  |  14 +
 13 files changed, 162 insertions(+), 105 deletions(-)

-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 3/7] powerpc: use task_pid_nr() for TID allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The current implementation of TID allocation, using a global IDR, may
result in an errant process starving the system of available TIDs.
Instead, use task_pid_nr(), as mentioned by the original author. The
scenario described which prevented it's use is not applicable, as
set_thread_tidr can only be called after the task struct has been
populated.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/switch_to.h |  1 -
 arch/powerpc/kernel/process.c| 97 +---
 2 files changed, 1 insertion(+), 97 deletions(-)

diff --git a/arch/powerpc/include/asm/switch_to.h 
b/arch/powerpc/include/asm/switch_to.h
index be8c9fa23983..5b03d8a82409 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -94,6 +94,5 @@ static inline void clear_task_ebb(struct task_struct *t)
 extern int set_thread_uses_vas(void);
 
 extern int set_thread_tidr(struct task_struct *t);
-extern void clear_thread_tidr(struct task_struct *t);
 
 #endif /* _ASM_POWERPC_SWITCH_TO_H */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 3b00da47699b..87f047fd2762 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1496,103 +1496,12 @@ int set_thread_uses_vas(void)
 }
 
 #ifdef CONFIG_PPC64
-static DEFINE_SPINLOCK(vas_thread_id_lock);
-static DEFINE_IDA(vas_thread_ida);
-
-/*
- * We need to assign a unique thread id to each thread in a process.
- *
- * This thread id, referred to as TIDR, and separate from the Linux's tgid,
- * is intended to be used to direct an ASB_Notify from the hardware to the
- * thread, when a suitable event occurs in the system.
- *
- * One such event is a "paste" instruction in the context of Fast Thread
- * Wakeup (aka Core-to-core wake up in the Virtual Accelerator Switchboard
- * (VAS) in POWER9.
- *
- * To get a unique TIDR per process we could simply reuse task_pid_nr() but
- * the problem is that task_pid_nr() is not yet available copy_thread() is
- * called. Fixing that would require changing more intrusive arch-neutral
- * code in code path in copy_process()?.
- *
- * Further, to assign unique TIDRs within each process, we need an atomic
- * field (or an IDR) in task_struct, which again intrudes into the arch-
- * neutral code. So try to assign globally unique TIDRs for now.
- *
- * NOTE: TIDR 0 indicates that the thread does not need a TIDR value.
- *  For now, only threads that expect to be notified by the VAS
- *  hardware need a TIDR value and we assign values > 0 for those.
- */
-#define MAX_THREAD_CONTEXT ((1 << 16) - 1)
-static int assign_thread_tidr(void)
-{
-   int index;
-   int err;
-   unsigned long flags;
-
-again:
-   if (!ida_pre_get(_thread_ida, GFP_KERNEL))
-   return -ENOMEM;
-
-   spin_lock_irqsave(_thread_id_lock, flags);
-   err = ida_get_new_above(_thread_ida, 1, );
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-
-   if (err == -EAGAIN)
-   goto again;
-   else if (err)
-   return err;
-
-   if (index > MAX_THREAD_CONTEXT) {
-   spin_lock_irqsave(_thread_id_lock, flags);
-   ida_remove(_thread_ida, index);
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-   return -ENOMEM;
-   }
-
-   return index;
-}
-
-static void free_thread_tidr(int id)
-{
-   unsigned long flags;
-
-   spin_lock_irqsave(_thread_id_lock, flags);
-   ida_remove(_thread_ida, id);
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-}
-
-/*
- * Clear any TIDR value assigned to this thread.
- */
-void clear_thread_tidr(struct task_struct *t)
-{
-   if (!t->thread.tidr)
-   return;
-
-   if (!cpu_has_feature(CPU_FTR_P9_TIDR)) {
-   WARN_ON_ONCE(1);
-   return;
-   }
-
-   mtspr(SPRN_TIDR, 0);
-   free_thread_tidr(t->thread.tidr);
-   t->thread.tidr = 0;
-}
-
-void arch_release_task_struct(struct task_struct *t)
-{
-   clear_thread_tidr(t);
-}
-
 /*
  * Assign a unique TIDR (thread id) for task @t and set it in the thread
  * structure. For now, we only support setting TIDR for 'current' task.
  */
 int set_thread_tidr(struct task_struct *t)
 {
-   int rc;
-
if (!cpu_has_feature(CPU_FTR_P9_TIDR))
return -EINVAL;
 
@@ -1602,11 +1511,7 @@ int set_thread_tidr(struct task_struct *t)
if (t->thread.tidr)
return 0;
 
-   rc = assign_thread_tidr();
-   if (rc < 0)
-   return rc;
-
-   t->thread.tidr = rc;
+   t->thread.tidr = (u16)task_pid_nr(t);
mtspr(SPRN_TIDR, t->thread.tidr);
 
return 0;
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH 2/7] powerpc: Use TIDR CPU feature to control TIDR allocation

[Alastair D'Silva]

On Tue, 2018-04-17 at 14:21 +1000, Andrew Donnellan wrote:
> On 17/04/18 12:09, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alast...@d-silva.org>
> > 
> > Switch the use of TIDR on it's CPU feature, rather than assuming it
> > is available based on architecture.
> > 
> > Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
> 
> There's a use of TIDR in restore_sprs() that's behind the ARCH_300
> flag 
> as well, ideally it should never trigger in the !P9_TIDR case, but
> you 
> might want to update that too for clarity?
> 

Thanks for the review, I'll include your suggestions in the next set.

-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 4/7] ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The function removes the process element from NPU cache.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/pnv-ocxl.h   | 2 +-
 arch/powerpc/platforms/powernv/ocxl.c | 4 ++--
 drivers/misc/ocxl/link.c  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pnv-ocxl.h 
b/arch/powerpc/include/asm/pnv-ocxl.h
index f6945d3bc971..208b5503f4ed 100644
--- a/arch/powerpc/include/asm/pnv-ocxl.h
+++ b/arch/powerpc/include/asm/pnv-ocxl.h
@@ -28,7 +28,7 @@ extern int pnv_ocxl_map_xsl_regs(struct pci_dev *dev, void 
__iomem **dsisr,
 extern int pnv_ocxl_spa_setup(struct pci_dev *dev, void *spa_mem, int PE_mask,
void **platform_data);
 extern void pnv_ocxl_spa_release(void *platform_data);
-extern int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle);
+extern int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int 
pe_handle);
 
 extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
 extern void pnv_ocxl_free_xive_irq(u32 irq);
diff --git a/arch/powerpc/platforms/powernv/ocxl.c 
b/arch/powerpc/platforms/powernv/ocxl.c
index fa9b53af3c7b..8c65aacda9c8 100644
--- a/arch/powerpc/platforms/powernv/ocxl.c
+++ b/arch/powerpc/platforms/powernv/ocxl.c
@@ -475,7 +475,7 @@ void pnv_ocxl_spa_release(void *platform_data)
 }
 EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
 
-int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle)
+int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
 {
struct spa_data *data = (struct spa_data *) platform_data;
int rc;
@@ -483,7 +483,7 @@ int pnv_ocxl_spa_remove_pe(void *platform_data, int 
pe_handle)
rc = opal_npu_spa_clear_cache(data->phb_opal_id, data->bdfn, pe_handle);
return rc;
 }
-EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe);
+EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe_from_cache);
 
 int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr)
 {
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index f30790582dc0..656e8610eec2 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -599,7 +599,7 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
 * On powerpc, the entry needs to be cleared from the context
 * cache of the NPU.
 */
-   rc = pnv_ocxl_spa_remove_pe(link->platform_data, pe_handle);
+   rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
WARN_ON(rc);
 
pe_data = radix_tree_delete(>pe_tree, pe_handle);
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 5/7] ocxl: Expose the thread_id needed for wait on p9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order to successfully issue as_notify, an AFU needs to know the TID
to notify, which in turn means that this information should be
available in userspace so it can be communicated to the AFU.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/context.c   |  5 +++-
 drivers/misc/ocxl/file.c  | 53 +++
 drivers/misc/ocxl/link.c  | 36 ++
 drivers/misc/ocxl/ocxl_internal.h |  1 +
 include/misc/ocxl.h   |  9 +++
 include/uapi/misc/ocxl.h  | 10 
 6 files changed, 113 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 909e8807824a..95f74623113e 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct 
ocxl_afu *afu,
mutex_init(>xsl_error_lock);
mutex_init(>irq_lock);
idr_init(>irq_idr);
+   ctx->tidr = 0;
+
/*
 * Keep a reference on the AFU to make sure it's valid for the
 * duration of the life of the context
@@ -65,6 +67,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 {
int rc;
 
+   // Locks both status & tidr
mutex_lock(>status_mutex);
if (ctx->status != OPENED) {
rc = -EIO;
@@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
}
 
rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
-   current->mm->context.id, 0, amr, current->mm,
+   current->mm->context.id, ctx->tidr, amr, current->mm,
xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 038509e5d031..eb409a469f21 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -5,6 +5,8 @@
 #include 
 #include 
 #include 
+#include 
+#include 
 #include "ocxl_internal.h"
 
 
@@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct ocxl_context 
*ctx,
return 0;
 }
 
+#ifdef CONFIG_PPC64
+static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
+   struct ocxl_ioctl_p9_wait __user *uarg)
+{
+   struct ocxl_ioctl_p9_wait arg;
+
+   memset(, 0, sizeof(arg));
+
+   if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
+   enum ocxl_context_status status;
+
+   // Locks both status & tidr
+   mutex_lock(>status_mutex);
+   if (!ctx->tidr) {
+   if (set_thread_tidr(current))
+   return -ENOENT;
+
+   ctx->tidr = current->thread.tidr;
+   }
+
+   status = ctx->status;
+   mutex_unlock(>status_mutex);
+
+   if (status == ATTACHED) {
+   int rc;
+   struct link *link = ctx->afu->fn->link;
+
+   rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr);
+   if (rc)
+   return rc;
+   }
+
+   arg.thread_id = ctx->tidr;
+   } else
+   return -ENOENT;
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+#endif
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
+   x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -186,6 +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
(struct ocxl_ioctl_metadata __user *) args);
break;
 
+#ifdef CONFIG_PPC64
+   case OCXL_IOCTL_ENABLE_P9_WAIT:
+   rc = afu_ioctl_enable_p9_wait(ctx,
+   (struct ocxl_ioctl_p9_wait __user *) args);
+   break;
+#endif
+
default:
rc = -EINVAL;
}
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 656e8610eec2..88876ae8f330 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -544,6 +544,42 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 
pidr, u32 tidr,
 }
 EXPORT_SYMBOL_GPL(ocxl_link_add_pe);
 
+int ocxl_link_update_pe(void *link_handle

[PATCH 6/7] ocxl: Add an IOCTL so userspace knows which platform the kernel requires

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

In order for a userspace AFU driver to call the Power9 specific
OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
make that call.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 drivers/misc/ocxl/file.c | 25 +
 include/uapi/misc/ocxl.h |  4 
 2 files changed, 29 insertions(+)

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index eb409a469f21..5a9f4f85aafd 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context 
*ctx,
 }
 #endif
 
+
+static long afu_ioctl_get_platform(struct ocxl_context *ctx,
+   struct ocxl_ioctl_platform __user *uarg)
+{
+   struct ocxl_ioctl_platform arg;
+
+   memset(, 0, sizeof(arg));
+
+#ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_P9_TIDR))
+   arg.flags[0] |= OCXL_IOCTL_PLATFORM_FLAGS0_P9_WAIT;
+#endif
+
+   if (copy_to_user(uarg, , sizeof(arg)))
+   return -EFAULT;
+
+   return 0;
+}
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :
\
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :   \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : 
\
+   x == OCXL_IOCTL_GET_PLATFORM ? "GET_PLATFORM" : \
"UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
break;
 #endif
 
+   case OCXL_IOCTL_GET_PLATFORM:
+   rc = afu_ioctl_get_platform(ctx,
+   (struct ocxl_ioctl_platform __user *) args);
+   break;
+
default:
rc = -EINVAL;
}
diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 8d2748e69c84..7bdd3efcf294 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -55,6 +55,9 @@ struct ocxl_ioctl_p9_wait {
__u64 reserved3[3];
 };
 
+#define OCXL_IOCTL_PLATFORM_FLAGS0_P9_WAIT 0x01
+struct ocxl_ioctl_platform {
+   __u64 flags[4];
 };
 
 struct ocxl_ioctl_irq_fd {
@@ -72,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
 #define OCXL_IOCTL_IRQ_SET_FD  _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
 #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct 
ocxl_ioctl_metadata)
 #define OCXL_IOCTL_ENABLE_P9_WAIT  _IOR(OCXL_MAGIC, 0x15, struct 
ocxl_ioctl_p9_wait)
+#define OCXL_IOCTL_GET_PLATFORM _IOR(OCXL_MAGIC, 0x16, struct 
ocxl_ioctl_platform)
 
 #endif /* _UAPI_MISC_OCXL_H */
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 7/7] ocxl: Document new OCXL IOCTLs

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 Documentation/accelerators/ocxl.rst | 10 ++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/accelerators/ocxl.rst 
b/Documentation/accelerators/ocxl.rst
index ddcc58d01cfb..144595a80a1c 100644
--- a/Documentation/accelerators/ocxl.rst
+++ b/Documentation/accelerators/ocxl.rst
@@ -157,6 +157,16 @@ OCXL_IOCTL_GET_METADATA:
   Obtains configuration information from the card, such at the size of
   MMIO areas, the AFU version, and the PASID for the current context.
 
+OCXL_IOCTL_ENABLE_P9_WAIT:
+
+  Allows the AFU to wake a userspace thread executing 'wait'. Returns
+  information to userspace to allow it to configure the AFU.
+
+OCXL_IOCTL_GET_PLATFORM:
+
+  Notifies userspace as to the platform the kernel believes we are on,
+  which may differ from what userspace believes. Also reports on which CPU
+  features which are usable from userspace.
 
 mmap
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 2/7] powerpc: Use TIDR CPU feature to control TIDR allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

Switch the use of TIDR on it's CPU feature, rather than assuming it
is available based on architecture.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1237f13fed51..a3e0a3e06d5a 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1570,7 +1570,7 @@ void clear_thread_tidr(struct task_struct *t)
if (!t->thread.tidr)
return;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR)) {
WARN_ON_ONCE(1);
return;
}
@@ -1593,7 +1593,7 @@ int set_thread_tidr(struct task_struct *t)
 {
int rc;
 
-   if (!cpu_has_feature(CPU_FTR_ARCH_300))
+   if (!cpu_has_feature(CPU_FTR_P9_TIDR))
return -EINVAL;
 
if (t != current)
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 3/7] powerpc: use task_pid_nr() for TID allocation

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The current implementation of TID allocation, using a global IDR, may
result in an errant process starving the system of available TIDs.
Instead, use task_pid_nr(), as mentioned by the original author. The
scenario described which prevented it's use is not applicable, as
set_thread_tidr can only be called after the task struct has been
populated.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/kernel/process.c | 97 +--
 1 file changed, 1 insertion(+), 96 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index a3e0a3e06d5a..56ff7eb5ff79 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1496,103 +1496,12 @@ int set_thread_uses_vas(void)
 }
 
 #ifdef CONFIG_PPC64
-static DEFINE_SPINLOCK(vas_thread_id_lock);
-static DEFINE_IDA(vas_thread_ida);
-
-/*
- * We need to assign a unique thread id to each thread in a process.
- *
- * This thread id, referred to as TIDR, and separate from the Linux's tgid,
- * is intended to be used to direct an ASB_Notify from the hardware to the
- * thread, when a suitable event occurs in the system.
- *
- * One such event is a "paste" instruction in the context of Fast Thread
- * Wakeup (aka Core-to-core wake up in the Virtual Accelerator Switchboard
- * (VAS) in POWER9.
- *
- * To get a unique TIDR per process we could simply reuse task_pid_nr() but
- * the problem is that task_pid_nr() is not yet available copy_thread() is
- * called. Fixing that would require changing more intrusive arch-neutral
- * code in code path in copy_process()?.
- *
- * Further, to assign unique TIDRs within each process, we need an atomic
- * field (or an IDR) in task_struct, which again intrudes into the arch-
- * neutral code. So try to assign globally unique TIDRs for now.
- *
- * NOTE: TIDR 0 indicates that the thread does not need a TIDR value.
- *  For now, only threads that expect to be notified by the VAS
- *  hardware need a TIDR value and we assign values > 0 for those.
- */
-#define MAX_THREAD_CONTEXT ((1 << 16) - 1)
-static int assign_thread_tidr(void)
-{
-   int index;
-   int err;
-   unsigned long flags;
-
-again:
-   if (!ida_pre_get(_thread_ida, GFP_KERNEL))
-   return -ENOMEM;
-
-   spin_lock_irqsave(_thread_id_lock, flags);
-   err = ida_get_new_above(_thread_ida, 1, );
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-
-   if (err == -EAGAIN)
-   goto again;
-   else if (err)
-   return err;
-
-   if (index > MAX_THREAD_CONTEXT) {
-   spin_lock_irqsave(_thread_id_lock, flags);
-   ida_remove(_thread_ida, index);
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-   return -ENOMEM;
-   }
-
-   return index;
-}
-
-static void free_thread_tidr(int id)
-{
-   unsigned long flags;
-
-   spin_lock_irqsave(_thread_id_lock, flags);
-   ida_remove(_thread_ida, id);
-   spin_unlock_irqrestore(_thread_id_lock, flags);
-}
-
-/*
- * Clear any TIDR value assigned to this thread.
- */
-void clear_thread_tidr(struct task_struct *t)
-{
-   if (!t->thread.tidr)
-   return;
-
-   if (!cpu_has_feature(CPU_FTR_P9_TIDR)) {
-   WARN_ON_ONCE(1);
-   return;
-   }
-
-   mtspr(SPRN_TIDR, 0);
-   free_thread_tidr(t->thread.tidr);
-   t->thread.tidr = 0;
-}
-
-void arch_release_task_struct(struct task_struct *t)
-{
-   clear_thread_tidr(t);
-}
-
 /*
  * Assign a unique TIDR (thread id) for task @t and set it in the thread
  * structure. For now, we only support setting TIDR for 'current' task.
  */
 int set_thread_tidr(struct task_struct *t)
 {
-   int rc;
-
if (!cpu_has_feature(CPU_FTR_P9_TIDR))
return -EINVAL;
 
@@ -1602,11 +1511,7 @@ int set_thread_tidr(struct task_struct *t)
if (t->thread.tidr)
return 0;
 
-   rc = assign_thread_tidr();
-   if (rc < 0)
-   return rc;
-
-   t->thread.tidr = rc;
+   t->thread.tidr = (u16)task_pid_nr(t);
mtspr(SPRN_TIDR, t->thread.tidr);
 
return 0;
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 1/7] powerpc: Add TIDR CPU feature for Power9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

This patch adds a CPU feature bit to show whether the CPU has
the TIDR register available, enabling as_notify/wait in userspace.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/cputable.h  | 3 ++-
 arch/powerpc/include/asm/switch_to.h | 1 -
 arch/powerpc/kernel/dt_cpu_ftrs.c| 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h 
b/arch/powerpc/include/asm/cputable.h
index 4e332f3531c5..54c4cbbe57b4 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -215,6 +215,7 @@ static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_P9_TM_HV_ASSIST
LONG_ASM_CONST(0x1000)
 #define CPU_FTR_P9_TM_XER_SO_BUG   LONG_ASM_CONST(0x2000)
 #define CPU_FTR_P9_TLBIE_BUG   LONG_ASM_CONST(0x4000)
+#define CPU_FTR_P9_TIDR
LONG_ASM_CONST(0x8000)
 
 #ifndef __ASSEMBLY__
 
@@ -462,7 +463,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY | \
-   CPU_FTR_P9_TLBIE_BUG)
+   CPU_FTR_P9_TLBIE_BUG | CPU_FTR_P9_TIDR)
 #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \
 (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
diff --git a/arch/powerpc/include/asm/switch_to.h 
b/arch/powerpc/include/asm/switch_to.h
index be8c9fa23983..5b03d8a82409 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -94,6 +94,5 @@ static inline void clear_task_ebb(struct task_struct *t)
 extern int set_thread_uses_vas(void);
 
 extern int set_thread_tidr(struct task_struct *t);
-extern void clear_thread_tidr(struct task_struct *t);
 
 #endif /* _ASM_POWERPC_SWITCH_TO_H */
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 11a3a4fed3fb..10f8b7f55637 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -722,6 +722,7 @@ static __init void cpufeatures_cpu_quirks(void)
if ((version & 0x) == 0x004e) {
cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+   cur_cpu_spec->cpu_features |= CPU_FTR_P9_TIDR;
}
 }
 
-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 0/7] ocxl: Implement Power9 as_notify/wait for OpenCAPI

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

The Power 9 as_notify/wait feature provides a lower latency way to
signal a thread that work is complete. This series enables the use of
this feature from OpenCAPI adapters, as well as addressing a potential
starvation issue when allocating thread IDs.

Alastair D'Silva (7):
  powerpc: Add TIDR CPU feature for Power9
  powerpc: Use TIDR CPU feature to control TIDR allocation
  powerpc: use task_pid_nr() for TID allocation
  ocxl: Rename pnv_ocxl_spa_remove_pe to clarify it's action
  ocxl: Expose the thread_id needed for wait on p9
  ocxl: Add an IOCTL so userspace knows which platform the kernel
requires
  ocxl: Document new OCXL IOCTLs

 Documentation/accelerators/ocxl.rst   | 10 
 arch/powerpc/include/asm/cputable.h   |  3 +-
 arch/powerpc/include/asm/pnv-ocxl.h   |  2 +-
 arch/powerpc/include/asm/switch_to.h  |  1 -
 arch/powerpc/kernel/dt_cpu_ftrs.c |  1 +
 arch/powerpc/kernel/process.c | 99 +--
 arch/powerpc/platforms/powernv/ocxl.c |  4 +-
 drivers/misc/ocxl/context.c   |  5 +-
 drivers/misc/ocxl/file.c  | 78 +++
 drivers/misc/ocxl/link.c  | 38 +-
 drivers/misc/ocxl/ocxl_internal.h |  1 +
 include/misc/ocxl.h   |  9 
 include/uapi/misc/ocxl.h  | 14 +
 13 files changed, 161 insertions(+), 104 deletions(-)

-- 
2.14.3

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html