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| author | Michael Neuling <mikey@neuling.org> | 2013-08-09 07:29:30 (GMT) |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2013-08-09 08:07:08 (GMT) |
| commit | c2d52644e2da8a07ecab5ca62dd0bc563089e8dc (patch) | |
| tree | a21b5652b82e1e0dee7e996c1c77c9d7ac5e9033 /arch/powerpc | |
| parent | 2517617e0de65f8f7cfe75cae745d06b1fa98586 (diff) | |
| download | linux-c2d52644e2da8a07ecab5ca62dd0bc563089e8dc.tar.xz | |
powerpc: Save the TAR register earlier
This moves us to save the Target Address Register (TAR) a earlier in
__switch_to. It introduces a new function save_tar() to do this.
We need to save the TAR earlier as we will overwrite it in the transactional
memory reclaim/recheckpoint path. We are going to do this in a subsequent
patch which will fix saving the TAR register when it's modified inside a
transaction.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> [v3.10]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/include/asm/switch_to.h | 9 | ||||
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 9 | ||||
| -rw-r--r-- | arch/powerpc/kernel/process.c | 10 |
3 files changed, 19 insertions, 9 deletions
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h index 49a13e0..294c2ce 100644 --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -15,6 +15,15 @@ extern struct task_struct *__switch_to(struct task_struct *, struct thread_struct; extern struct task_struct *_switch(struct thread_struct *prev, struct thread_struct *next); +#ifdef CONFIG_PPC_BOOK3S_64 +static inline void save_tar(struct thread_struct *prev) +{ + if (cpu_has_feature(CPU_FTR_ARCH_207S)) + prev->tar = mfspr(SPRN_TAR); +} +#else +static inline void save_tar(struct thread_struct *prev) {} +#endif extern void giveup_fpu(struct task_struct *); extern void load_up_fpu(void); diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 4674fe6..2bd0b88 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -449,15 +449,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_DSCR) #ifdef CONFIG_PPC_BOOK3S_64 BEGIN_FTR_SECTION - /* - * Back up the TAR across context switches. Note that the TAR is not - * available for use in the kernel. (To provide this, the TAR should - * be backed up/restored on exception entry/exit instead, and be in - * pt_regs. FIXME, this should be in pt_regs anyway (for debug).) - */ - mfspr r0,SPRN_TAR - std r0,THREAD_TAR(r3) - /* Event based branch registers */ mfspr r0, SPRN_BESCR std r0, THREAD_BESCR(r3) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index c517dbe..8083be2 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -600,6 +600,16 @@ struct task_struct *__switch_to(struct task_struct *prev, struct ppc64_tlb_batch *batch; #endif + /* Back up the TAR across context switches. + * Note that the TAR is not available for use in the kernel. (To + * provide this, the TAR should be backed up/restored on exception + * entry/exit instead, and be in pt_regs. FIXME, this should be in + * pt_regs anyway (for debug).) + * Save the TAR here before we do treclaim/trecheckpoint as these + * will change the TAR. + */ + save_tar(&prev->thread); + __switch_to_tm(prev); #ifdef CONFIG_SMP |