AuxXxilium/linux_dsm_epyc7002
1
0
Fork 0
mirror of https://github.com/AuxXxilium/linux_dsm_epyc7002.git synced 2025-02-10 09:25:16 +07:00
Code Issues Actions Packages Projects Releases Wiki Activity

powerpc: Avoid load hit store in __giveup_fpu() and __giveup_altivec()

Browse Source 
In both __giveup_fpu() and __giveup_altivec() we make two modifications
to tsk->thread.regs->msr. gcc decides to do a read/modify/write of
each change, so we end up with a load hit store:

        ld      r9,264(r10)
        rldicl  r9,r9,50,1
        rotldi  r9,r9,14
        std     r9,264(r10)
...
        ld      r9,264(r10)
        rldicl  r9,r9,40,1
        rotldi  r9,r9,24
        std     r9,264(r10)

Fix this by using a temporary.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Anton Blanchard 2016-05-29 22:03:50 +10:00 committed by Michael Ellerman
parent 5edb56491d
commit 8eb9803723
1 changed files with 12 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
arch/powerpc/kernel/process.c
View File

@ -139,12 +139,16 @@ EXPORT_SYMBOL(__msr_check_and_clear);
#ifdef CONFIG_PPC_FPU #ifdef CONFIG_PPC_FPU
void __giveup_fpu(struct task_struct *tsk) void __giveup_fpu(struct task_struct *tsk)
{ {
unsigned long msr;
save_fpu(tsk); save_fpu(tsk);
tsk->thread.regs->msr &= ~MSR_FP; msr = tsk->thread.regs->msr;
msr &= ~MSR_FP;
#ifdef CONFIG_VSX #ifdef CONFIG_VSX
if (cpu_has_feature(CPU_FTR_VSX)) if (cpu_has_feature(CPU_FTR_VSX))
tsk->thread.regs->msr &= ~MSR_VSX; msr &= ~MSR_VSX;
#endif #endif
tsk->thread.regs->msr = msr;
} }
void giveup_fpu(struct task_struct *tsk) void giveup_fpu(struct task_struct *tsk)
@ -219,12 +223,16 @@ static int restore_fp(struct task_struct *tsk) { return 0; }
static void __giveup_altivec(struct task_struct *tsk) static void __giveup_altivec(struct task_struct *tsk)
{ {
unsigned long msr;
save_altivec(tsk); save_altivec(tsk);
tsk->thread.regs->msr &= ~MSR_VEC; msr = tsk->thread.regs->msr;
msr &= ~MSR_VEC;
#ifdef CONFIG_VSX #ifdef CONFIG_VSX
if (cpu_has_feature(CPU_FTR_VSX)) if (cpu_has_feature(CPU_FTR_VSX))
tsk->thread.regs->msr &= ~MSR_VSX; msr &= ~MSR_VSX;
#endif #endif
tsk->thread.regs->msr = msr;
} }
void giveup_altivec(struct task_struct *tsk) void giveup_altivec(struct task_struct *tsk)