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powerpc: Create msr_check_and_{set,clear}() 

Create helper functions to set and clear MSR bits after first
checking if they are already set. Grouping them will make it
easy to avoid the MSR writes in a subsequent optimisation.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Anton Blanchard 2015-10-29 11:44:04 +11:00 committed by Michael Ellerman
parent 1552cd703c
commit a0e72cf12b
1 changed files with 56 additions and 59 deletions
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115
arch/powerpc/kernel/process.c
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@ -87,23 +87,46 @@ static void check_if_tm_restore_required(struct task_struct *tsk)
static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
static void msr_check_and_set(unsigned long bits)
{
unsigned long oldmsr = mfmsr();
unsigned long newmsr;
newmsr = oldmsr | bits;
#ifdef CONFIG_VSX
if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP))
newmsr |= MSR_VSX;
#endif
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
}
static void msr_check_and_clear(unsigned long bits)
{
unsigned long oldmsr = mfmsr();
unsigned long newmsr;
newmsr = oldmsr & ~bits;
#ifdef CONFIG_VSX
if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP))
newmsr &= ~MSR_VSX;
#endif
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
}
#ifdef CONFIG_PPC_FPU
void giveup_fpu(struct task_struct *tsk)
{
u64 oldmsr = mfmsr();
u64 newmsr;
check_if_tm_restore_required(tsk);
newmsr = oldmsr | MSR_FP;
#ifdef CONFIG_VSX
if (cpu_has_feature(CPU_FTR_VSX))
newmsr |= MSR_VSX;
#endif
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
msr_check_and_set(MSR_FP);
__giveup_fpu(tsk);
msr_check_and_clear(MSR_FP);
}
EXPORT_SYMBOL(giveup_fpu);
@ -144,30 +167,21 @@ void enable_kernel_fp(void)
{
WARN_ON(preemptible());
if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) {
giveup_fpu(current);
} else {
u64 oldmsr = mfmsr();
msr_check_and_set(MSR_FP);
if (!(oldmsr & MSR_FP))
mtmsr_isync(oldmsr | MSR_FP);
}
if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
__giveup_fpu(current);
}
EXPORT_SYMBOL(enable_kernel_fp);
#ifdef CONFIG_ALTIVEC
void giveup_altivec(struct task_struct *tsk)
{
u64 oldmsr = mfmsr();
u64 newmsr;
check_if_tm_restore_required(tsk);
newmsr = oldmsr | MSR_VEC;
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
msr_check_and_set(MSR_VEC);
__giveup_altivec(tsk);
msr_check_and_clear(MSR_VEC);
}
EXPORT_SYMBOL(giveup_altivec);
@ -175,14 +189,10 @@ void enable_kernel_altivec(void)
{
WARN_ON(preemptible());
if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) {
giveup_altivec(current);
} else {
u64 oldmsr = mfmsr();
msr_check_and_set(MSR_VEC);
if (!(oldmsr & MSR_VEC))
mtmsr_isync(oldmsr | MSR_VEC);
}
if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
__giveup_altivec(current);
}
EXPORT_SYMBOL(enable_kernel_altivec);
@ -207,20 +217,15 @@ EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
#ifdef CONFIG_VSX
void giveup_vsx(struct task_struct *tsk)
{
u64 oldmsr = mfmsr();
u64 newmsr;
check_if_tm_restore_required(tsk);
newmsr = oldmsr | (MSR_FP|MSR_VEC|MSR_VSX);
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);
if (tsk->thread.regs->msr & MSR_FP)
__giveup_fpu(tsk);
if (tsk->thread.regs->msr & MSR_VEC)
__giveup_altivec(tsk);
__giveup_vsx(tsk);
msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX);
}
EXPORT_SYMBOL(giveup_vsx);
@ -228,13 +233,14 @@ void enable_kernel_vsx(void)
{
WARN_ON(preemptible());
if (current->thread.regs && (current->thread.regs->msr & MSR_VSX)) {
giveup_vsx(current);
} else {
u64 oldmsr = mfmsr();
msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);
if (!(oldmsr & MSR_VSX))
mtmsr_isync(oldmsr | MSR_VSX);
if (current->thread.regs && (current->thread.regs->msr & MSR_VSX)) {
if (current->thread.regs->msr & MSR_FP)
__giveup_fpu(current);
if (current->thread.regs->msr & MSR_VEC)
__giveup_altivec(current);
__giveup_vsx(current);
}
}
EXPORT_SYMBOL(enable_kernel_vsx);
@ -256,16 +262,11 @@ EXPORT_SYMBOL_GPL(flush_vsx_to_thread);
#ifdef CONFIG_SPE
void giveup_spe(struct task_struct *tsk)
{
u64 oldmsr = mfmsr();
u64 newmsr;
check_if_tm_restore_required(tsk);
newmsr = oldmsr | MSR_SPE;
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
msr_check_and_set(MSR_SPE);
__giveup_spe(tsk);
msr_check_and_clear(MSR_SPE);
}
EXPORT_SYMBOL(giveup_spe);
@ -273,14 +274,10 @@ void enable_kernel_spe(void)
{
WARN_ON(preemptible());
if (current->thread.regs && (current->thread.regs->msr & MSR_SPE)) {
giveup_spe(current);
} else {
u64 oldmsr = mfmsr();
msr_check_and_set(MSR_SPE);
if (!(oldmsr & MSR_SPE))
mtmsr_isync(oldmsr | MSR_SPE);
}
if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
__giveup_spe(current);
}
EXPORT_SYMBOL(enable_kernel_spe);