Re: [PATCH v3] powerpc/kernel/sysfs: Export ldbar spr to sysfs

[Anju T Sudhakar]

Hi,


On Tuesday 06 March 2018 04:35 PM, Michael Ellerman wrote:

Anju T Sudhakar  writes:


diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 4437c70..caefb64 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
device_create_file(s, _attrs[i]);
  
  #ifdef CONFIG_PPC64

+   if (cpu_has_feature(CPU_FTR_ARCH_300))
+   device_create_file(s, _attr_ldbar);

Is this register readable in supervisor state?


This is a nice catch, thanks. :)
The guest kernel can not access the register, it is only readable in the 
hypervisor state.
I will resend the patch with a condition check so that this spr will not 
get registered for guest kernel.



Regards,
Anju


cheers

Re: [PATCH v3] powerpc/kernel/sysfs: Export ldbar spr to sysfs

[Anju T Sudhakar]

Hi,


On Tuesday 06 March 2018 04:35 PM, Michael Ellerman wrote:

Anju T Sudhakar  writes:


diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 4437c70..caefb64 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
device_create_file(s, _attrs[i]);
  
  #ifdef CONFIG_PPC64

+   if (cpu_has_feature(CPU_FTR_ARCH_300))
+   device_create_file(s, _attr_ldbar);

Is this register readable in supervisor state?


This is a nice catch, thanks. :)
The guest kernel can not access the register, it is only readable in the 
hypervisor state.
I will resend the patch with a condition check so that this spr will not 
get registered for guest kernel.



Regards,
Anju


cheers

Re: [PATCH v3] powerpc/kernel/sysfs: Export ldbar spr to sysfs

[Michael Ellerman]

Anju T Sudhakar  writes:

> diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
> index 4437c70..caefb64 100644
> --- a/arch/powerpc/kernel/sysfs.c
> +++ b/arch/powerpc/kernel/sysfs.c
> @@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
>   device_create_file(s, _attrs[i]);
>  
>  #ifdef CONFIG_PPC64
> + if (cpu_has_feature(CPU_FTR_ARCH_300))
> + device_create_file(s, _attr_ldbar);

Is this register readable in supervisor state?

cheers

Re: [PATCH v3] powerpc/kernel/sysfs: Export ldbar spr to sysfs

[Michael Ellerman]

Anju T Sudhakar  writes:

> diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
> index 4437c70..caefb64 100644
> --- a/arch/powerpc/kernel/sysfs.c
> +++ b/arch/powerpc/kernel/sysfs.c
> @@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
>   device_create_file(s, _attrs[i]);
>  
>  #ifdef CONFIG_PPC64
> + if (cpu_has_feature(CPU_FTR_ARCH_300))
> + device_create_file(s, _attr_ldbar);

Is this register readable in supervisor state?

cheers

Re: [PATCH v3] powerpc/kernel/sysfs: Export ldbar spr to sysfs

[Anju T Sudhakar]

Hi,

Kindly ignore this patch, I send a wrong version. Will send out the 
right one.



Thanks,

Anju


On Thursday 09 November 2017 05:43 PM, Anju T Sudhakar wrote:

Add ldbar spr to sysfs. The spr holds thread level In-Memory Collection (IMC)
counter configuration data. Exposing this will help to understand the current
configuration of thread-level counters in the system.
Primarily, Bit 0 of ldbar says whether the counters are enabled or not.
And bit 1 indicates the mode (if 0-Accumulation Mode/if 1-Trace Mode).

Signed-off-by: Anju T Sudhakar 
---
  arch/powerpc/kernel/sysfs.c | 8 
  1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 4437c70..f8caee0 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -485,6 +485,7 @@ SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
  SYSFS_SPRSETUP(purr, SPRN_PURR);
  SYSFS_SPRSETUP(spurr, SPRN_SPURR);
  SYSFS_SPRSETUP(pir, SPRN_PIR);
+SYSFS_SPRSETUP(ldbar, SPRN_LDBAR);

  /*
Lets only enable read for phyp resources and
@@ -492,6 +493,7 @@ SYSFS_SPRSETUP(pir, SPRN_PIR);
Lets be conservative and default to pseries.
  */
  static DEVICE_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
+static DEVICE_ATTR(ldbar, 0400, show_ldbar, store_ldbar);
  static DEVICE_ATTR(spurr, 0400, show_spurr, NULL);
  static DEVICE_ATTR(purr, 0400, show_purr, store_purr);
  static DEVICE_ATTR(pir, 0400, show_pir, NULL);
@@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
device_create_file(s, _attrs[i]);

  #ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_ARCH_300))
+   device_create_file(s, _attr_ldbar);
+
if (cpu_has_feature(CPU_FTR_MMCRA))
device_create_file(s, _attr_mmcra);

@@ -842,6 +847,9 @@ static int unregister_cpu_online(unsigned int cpu)
device_remove_file(s, _attrs[i]);

  #ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_ARCH_300))
+   device_remove_file(s, _attr_ldbar);
+
if (cpu_has_feature(CPU_FTR_MMCRA))
device_remove_file(s, _attr_mmcra);

Re: [PATCH v3] powerpc/kernel/sysfs: Export ldbar spr to sysfs

[Anju T Sudhakar]

Hi,

Kindly ignore this patch, I send a wrong version. Will send out the 
right one.



Thanks,

Anju


On Thursday 09 November 2017 05:43 PM, Anju T Sudhakar wrote:

Add ldbar spr to sysfs. The spr holds thread level In-Memory Collection (IMC)
counter configuration data. Exposing this will help to understand the current
configuration of thread-level counters in the system.
Primarily, Bit 0 of ldbar says whether the counters are enabled or not.
And bit 1 indicates the mode (if 0-Accumulation Mode/if 1-Trace Mode).

Signed-off-by: Anju T Sudhakar 
---
  arch/powerpc/kernel/sysfs.c | 8 
  1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 4437c70..f8caee0 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -485,6 +485,7 @@ SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
  SYSFS_SPRSETUP(purr, SPRN_PURR);
  SYSFS_SPRSETUP(spurr, SPRN_SPURR);
  SYSFS_SPRSETUP(pir, SPRN_PIR);
+SYSFS_SPRSETUP(ldbar, SPRN_LDBAR);

  /*
Lets only enable read for phyp resources and
@@ -492,6 +493,7 @@ SYSFS_SPRSETUP(pir, SPRN_PIR);
Lets be conservative and default to pseries.
  */
  static DEVICE_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
+static DEVICE_ATTR(ldbar, 0400, show_ldbar, store_ldbar);
  static DEVICE_ATTR(spurr, 0400, show_spurr, NULL);
  static DEVICE_ATTR(purr, 0400, show_purr, store_purr);
  static DEVICE_ATTR(pir, 0400, show_pir, NULL);
@@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
device_create_file(s, _attrs[i]);

  #ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_ARCH_300))
+   device_create_file(s, _attr_ldbar);
+
if (cpu_has_feature(CPU_FTR_MMCRA))
device_create_file(s, _attr_mmcra);

@@ -842,6 +847,9 @@ static int unregister_cpu_online(unsigned int cpu)
device_remove_file(s, _attrs[i]);

  #ifdef CONFIG_PPC64
+   if (cpu_has_feature(CPU_FTR_ARCH_300))
+   device_remove_file(s, _attr_ldbar);
+
if (cpu_has_feature(CPU_FTR_MMCRA))
device_remove_file(s, _attr_mmcra);