Re: [RFC PATCH 05/12] [WIP] powerpc/tm: Reclaim/recheckpoint on entry/exit
On Tue, 2018-02-20 at 16:25 +1100, Michael Neuling wrote: > > > > @@ -1055,6 +1082,8 @@ void restore_tm_state(struct pt_regs *regs) > > > > msr_diff = current->thread.ckpt_regs.msr & ~regs->msr; > > > > msr_diff &= MSR_FP | MSR_VEC | MSR_VSX; > > > > > > > > + tm_recheckpoint(¤t->thread); > > > > + > > > > > > So why do we do tm_recheckpoint at all? Shouldn't most of the tm_blah > > > code go > > > away in process.c after all this? > > > > > > > I'm not sure I follow, we need to recheckpoint because we're going back > > to userspace? Or would you rather calling the tm.S code directly from > > the exception return path? > > Yeah, I was thinking the point of this series was. We do tm_reclaim right on > entry and tm_recheckpoint right on exit. > Yeah that's the ultimate goal, considering I haven't been attacked or offered more drugs I feel like what I've done isn't crazy. Your feedback is great, thanks. > The bits in between (ie. the tm_blah() calls process.c) would mostly go away. > > > > Yes, I hope we'll be able to have a fairly big cleanup commit of tm_ > > code in process.c at the end of this series. > > Yep, agreed. > > Mikey
Re: [RFC PATCH 05/12] [WIP] powerpc/tm: Reclaim/recheckpoint on entry/exit
> > > @@ -1055,6 +1082,8 @@ void restore_tm_state(struct pt_regs *regs) > > > msr_diff = current->thread.ckpt_regs.msr & ~regs->msr; > > > msr_diff &= MSR_FP | MSR_VEC | MSR_VSX; > > > > > > + tm_recheckpoint(¤t->thread); > > > + > > > > So why do we do tm_recheckpoint at all? Shouldn't most of the tm_blah code > > go > > away in process.c after all this? > > > > I'm not sure I follow, we need to recheckpoint because we're going back > to userspace? Or would you rather calling the tm.S code directly from > the exception return path? Yeah, I was thinking the point of this series was. We do tm_reclaim right on entry and tm_recheckpoint right on exit. The bits in between (ie. the tm_blah() calls process.c) would mostly go away. > Yes, I hope we'll be able to have a fairly big cleanup commit of tm_ > code in process.c at the end of this series. Yep, agreed. Mikey
Re: [RFC PATCH 05/12] [WIP] powerpc/tm: Reclaim/recheckpoint on entry/exit
On Tue, 2018-02-20 at 13:50 +1100, Michael Neuling wrote: > On Tue, 2018-02-20 at 11:22 +1100, Cyril Bur wrote: > > > The comment from the cover sheet should be here > > > --- > > arch/powerpc/include/asm/exception-64s.h | 25 + > > arch/powerpc/kernel/entry_64.S | 5 + > > arch/powerpc/kernel/process.c| 37 > > > > 3 files changed, 63 insertions(+), 4 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/exception-64s.h > > b/arch/powerpc/include/asm/exception-64s.h > > index 471b2274fbeb..f904f19a9ec2 100644 > > --- a/arch/powerpc/include/asm/exception-64s.h > > +++ b/arch/powerpc/include/asm/exception-64s.h > > @@ -35,6 +35,7 @@ > > * implementations as possible. > > */ > > #include > > +#include > > > > /* PACA save area offsets (exgen, exmc, etc) */ > > #define EX_R9 0 > > @@ -127,6 +128,26 @@ > > hrfid; \ > > b hrfi_flush_fallback > > > > +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM > > +#define TM_KERNEL_ENTRY > > \ > > + ld r3,_MSR(r1);\ > > + /* Probably don't need to check if coming from user/kernel */ \ > > + /* If TM is suspended or active then we must have come from*/ \ > > + /* userspace */ \ > > + andi. r0,r3,MSR_PR; \ > > + beq 1f; \ > > + rldicl. r3,r3,(64-MSR_TS_LG),(64-2); /* SUSPENDED or ACTIVE*/ \ > > + beql+ 1f; /* Not SUSPENDED or ACTIVE */ \ > > + bl save_nvgprs;\ > > + RECONCILE_IRQ_STATE(r10,r11); \ > > + li r3,TM_CAUSE_MISC; \ > > + bl tm_reclaim_current; /* uint8 cause */ \ > > +1: > > + > > +#else /* CONFIG_PPC_TRANSACTIONAL_MEM */ > > +#define TM_KERNEL_ENTRY > > +#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ > > + > > #ifdef CONFIG_RELOCATABLE > > #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h) > > \ > > mfspr r11,SPRN_##h##SRR0; /* save SRR0 */ \ > > @@ -675,6 +696,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_CTRL) > > EXCEPTION_PROLOG_COMMON(trap, area);\ > > /* Volatile regs are potentially clobbered here */ \ > > additions; \ > > + /* This is going to need to go somewhere else as well */\ > > + /* See comment in tm_recheckpoint() */\ > > + TM_KERNEL_ENTRY;\ > > addir3,r1,STACK_FRAME_OVERHEAD; \ > > bl hdlr; \ > > b ret > > @@ -689,6 +713,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CTRL) > > EXCEPTION_PROLOG_COMMON_3(trap);\ > > /* Volatile regs are potentially clobbered here */ \ > > additions; \ > > + TM_KERNEL_ENTRY;\ > > addir3,r1,STACK_FRAME_OVERHEAD; \ > > bl hdlr > > > > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S > > index 2cb5109a7ea3..107c15c6f48b 100644 > > --- a/arch/powerpc/kernel/entry_64.S > > +++ b/arch/powerpc/kernel/entry_64.S > > @@ -126,6 +126,11 @@ BEGIN_FW_FTR_SECTION > > 33: > > END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR) > > #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE && CONFIG_PPC_SPLPAR */ > > + TM_KERNEL_ENTRY > > + REST_GPR(0,r1) > > + REST_4GPRS(3,r1) > > + REST_2GPRS(7,r1) > > + addir9,r1,STACK_FRAME_OVERHEAD > > Why are we doing these restores here now? The syscall handler expects the syscall params to still be in their respective regs. > > > > > /* > > * A syscall should always be called with interrupts enabled > > diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c > > index 77dc6d8288eb..ea75da0fd506 100644 > > --- a/arch/powerpc/kernel/process.c > > +++ b/arch/powerpc/kernel/process.c > > @@ -951,6 +951,23 @@ void tm_recheckpoint(struct thread_struct *thread) > > if (!(thread->regs->msr & MSR_TM)) > > return; > > > > + /* > > +* This is 'that' comment. > > I think I'm in the loop here but I don't actually know what this means. > > Senior Mikey moment or Crazy Cyril comments? I'll let the peanut gallery > decide. > Oh quite possibly crazy Cyril comment that will have to be... normalised. I should actually delete this and see if that's still the case. > > +* > > +* If we get where with tm suspended or active then something > > s/where/here/ > > > +* has gone wron
Re: [RFC PATCH 05/12] [WIP] powerpc/tm: Reclaim/recheckpoint on entry/exit
On Tue, 2018-02-20 at 11:22 +1100, Cyril Bur wrote: The comment from the cover sheet should be here > --- > arch/powerpc/include/asm/exception-64s.h | 25 + > arch/powerpc/kernel/entry_64.S | 5 + > arch/powerpc/kernel/process.c| 37 > > 3 files changed, 63 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/include/asm/exception-64s.h > b/arch/powerpc/include/asm/exception-64s.h > index 471b2274fbeb..f904f19a9ec2 100644 > --- a/arch/powerpc/include/asm/exception-64s.h > +++ b/arch/powerpc/include/asm/exception-64s.h > @@ -35,6 +35,7 @@ > * implementations as possible. > */ > #include > +#include > > /* PACA save area offsets (exgen, exmc, etc) */ > #define EX_R90 > @@ -127,6 +128,26 @@ > hrfid; \ > b hrfi_flush_fallback > > +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM > +#define TM_KERNEL_ENTRY > \ > + ld r3,_MSR(r1);\ > + /* Probably don't need to check if coming from user/kernel */ \ > + /* If TM is suspended or active then we must have come from*/ \ > + /* userspace */ \ > + andi. r0,r3,MSR_PR; \ > + beq 1f; \ > + rldicl. r3,r3,(64-MSR_TS_LG),(64-2); /* SUSPENDED or ACTIVE*/ \ > + beql+ 1f; /* Not SUSPENDED or ACTIVE */ \ > + bl save_nvgprs;\ > + RECONCILE_IRQ_STATE(r10,r11); \ > + li r3,TM_CAUSE_MISC; \ > + bl tm_reclaim_current; /* uint8 cause */ \ > +1: > + > +#else /* CONFIG_PPC_TRANSACTIONAL_MEM */ > +#define TM_KERNEL_ENTRY > +#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ > + > #ifdef CONFIG_RELOCATABLE > #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h) \ > mfspr r11,SPRN_##h##SRR0; /* save SRR0 */ \ > @@ -675,6 +696,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_CTRL) > EXCEPTION_PROLOG_COMMON(trap, area);\ > /* Volatile regs are potentially clobbered here */ \ > additions; \ > + /* This is going to need to go somewhere else as well */\ > + /* See comment in tm_recheckpoint() */\ > + TM_KERNEL_ENTRY;\ > addir3,r1,STACK_FRAME_OVERHEAD; \ > bl hdlr; \ > b ret > @@ -689,6 +713,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CTRL) > EXCEPTION_PROLOG_COMMON_3(trap);\ > /* Volatile regs are potentially clobbered here */ \ > additions; \ > + TM_KERNEL_ENTRY;\ > addir3,r1,STACK_FRAME_OVERHEAD; \ > bl hdlr > > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S > index 2cb5109a7ea3..107c15c6f48b 100644 > --- a/arch/powerpc/kernel/entry_64.S > +++ b/arch/powerpc/kernel/entry_64.S > @@ -126,6 +126,11 @@ BEGIN_FW_FTR_SECTION > 33: > END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR) > #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE && CONFIG_PPC_SPLPAR */ > + TM_KERNEL_ENTRY > + REST_GPR(0,r1) > + REST_4GPRS(3,r1) > + REST_2GPRS(7,r1) > + addir9,r1,STACK_FRAME_OVERHEAD Why are we doing these restores here now? > > /* >* A syscall should always be called with interrupts enabled > diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c > index 77dc6d8288eb..ea75da0fd506 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -951,6 +951,23 @@ void tm_recheckpoint(struct thread_struct *thread) > if (!(thread->regs->msr & MSR_TM)) > return; > > + /* > + * This is 'that' comment. I think I'm in the loop here but I don't actually know what this means. Senior Mikey moment or Crazy Cyril comments? I'll let the peanut gallery decide. > + * > + * If we get where with tm suspended or active then something s/where/here/ > + * has gone wrong. I've added this now as a proof of concept. > + * > + * The problem I'm seeing without it is an attempt to > + * recheckpoint a CPU without a previous reclaim. > + * > + * I'm probably missed an exception entry with the > + * TM_KERNEL_ENTRY macro. Should be easy enough to find. > + */ > + if (MSR_TM_ACTIVE(mfmsr())) > + return; I don't really get this. Wouldn't this test
[RFC PATCH 05/12] [WIP] powerpc/tm: Reclaim/recheckpoint on entry/exit
---
arch/powerpc/include/asm/exception-64s.h | 25 +
arch/powerpc/kernel/entry_64.S | 5 +
arch/powerpc/kernel/process.c| 37
3 files changed, 63 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/exception-64s.h
b/arch/powerpc/include/asm/exception-64s.h
index 471b2274fbeb..f904f19a9ec2 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -35,6 +35,7 @@
* implementations as possible.
*/
#include
+#include
/* PACA save area offsets (exgen, exmc, etc) */
#define EX_R9 0
@@ -127,6 +128,26 @@
hrfid; \
b hrfi_flush_fallback
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+#define TM_KERNEL_ENTRY
\
+ ld r3,_MSR(r1);\
+ /* Probably don't need to check if coming from user/kernel */ \
+ /* If TM is suspended or active then we must have come from*/ \
+ /* userspace */ \
+ andi. r0,r3,MSR_PR; \
+ beq 1f; \
+ rldicl. r3,r3,(64-MSR_TS_LG),(64-2); /* SUSPENDED or ACTIVE*/ \
+ beql+ 1f; /* Not SUSPENDED or ACTIVE */ \
+ bl save_nvgprs;\
+ RECONCILE_IRQ_STATE(r10,r11); \
+ li r3,TM_CAUSE_MISC; \
+ bl tm_reclaim_current; /* uint8 cause */ \
+1:
+
+#else /* CONFIG_PPC_TRANSACTIONAL_MEM */
+#define TM_KERNEL_ENTRY
+#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
+
#ifdef CONFIG_RELOCATABLE
#define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h) \
mfspr r11,SPRN_##h##SRR0; /* save SRR0 */ \
@@ -675,6 +696,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_CTRL)
EXCEPTION_PROLOG_COMMON(trap, area);\
/* Volatile regs are potentially clobbered here */ \
additions; \
+ /* This is going to need to go somewhere else as well */\
+ /* See comment in tm_recheckpoint() */\
+ TM_KERNEL_ENTRY;\
addir3,r1,STACK_FRAME_OVERHEAD; \
bl hdlr; \
b ret
@@ -689,6 +713,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CTRL)
EXCEPTION_PROLOG_COMMON_3(trap);\
/* Volatile regs are potentially clobbered here */ \
additions; \
+ TM_KERNEL_ENTRY;\
addir3,r1,STACK_FRAME_OVERHEAD; \
bl hdlr
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 2cb5109a7ea3..107c15c6f48b 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -126,6 +126,11 @@ BEGIN_FW_FTR_SECTION
33:
END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE && CONFIG_PPC_SPLPAR */
+ TM_KERNEL_ENTRY
+ REST_GPR(0,r1)
+ REST_4GPRS(3,r1)
+ REST_2GPRS(7,r1)
+ addir9,r1,STACK_FRAME_OVERHEAD
/*
* A syscall should always be called with interrupts enabled
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 77dc6d8288eb..ea75da0fd506 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -951,6 +951,23 @@ void tm_recheckpoint(struct thread_struct *thread)
if (!(thread->regs->msr & MSR_TM))
return;
+ /*
+* This is 'that' comment.
+*
+* If we get where with tm suspended or active then something
+* has gone wrong. I've added this now as a proof of concept.
+*
+* The problem I'm seeing without it is an attempt to
+* recheckpoint a CPU without a previous reclaim.
+*
+* I'm probably missed an exception entry with the
+* TM_KERNEL_ENTRY macro. Should be easy enough to find.
+*/
+ if (MSR_TM_ACTIVE(mfmsr()))
+ return;
+
+ tm_enable();
+
/* We really can't be interrupted here as the TEXASR registers can't
* change and later in the trecheckpoint code, we have a userspace R1.
* So let's hard disable over this region.
@@ -1009,6 +1026,13 @@ static inline void tm_recheckpoint_new_task(struct
task_struct *new)
static inline void __switch_to_tm(struct task_struct *prev,
struct task_struct *new)
{
+ /*
+* So, with the rewor
