Message ID | 20160817034323.23053-5-cyrilbur@gmail.com (mailing list archive) |
---|---|
State | Changes Requested |
Headers | show |
On Wed, 2016-08-17 at 13:43 +1000, Cyril Bur wrote: I obviously didn't proof read that one. This commit message should have read: mfmsr() is a fairly expensive call and callers of msr_check_and_set() may want to make decisions based on the MSR bits that it did not change but may not know the value of. This patch would avoid two calls to mfmsr(). > mfmsr() is a fairly expensive call and callers of msr_check_and_set() > may want to make decisions bits in the MSR that it did not change but > may not know the value of. > > This patch would avoid a two calls to mfmsr(). > > Signed-off-by: Cyril Bur <cyrilbur@gmail.com> > --- > arch/powerpc/include/asm/reg.h | 2 +- > arch/powerpc/kernel/process.c | 4 +++- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/include/asm/reg.h > b/arch/powerpc/include/asm/reg.h > index f69f40f..0a3dde9 100644 > --- a/arch/powerpc/include/asm/reg.h > +++ b/arch/powerpc/include/asm/reg.h > @@ -1247,7 +1247,7 @@ static inline void mtmsr_isync(unsigned long > val) > : "memory") > #endif > > -extern void msr_check_and_set(unsigned long bits); > +extern unsigned long msr_check_and_set(unsigned long bits); > extern bool strict_msr_control; > extern void __msr_check_and_clear(unsigned long bits); > static inline void msr_check_and_clear(unsigned long bits) > diff --git a/arch/powerpc/kernel/process.c > b/arch/powerpc/kernel/process.c > index 82308fd..c42581b 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -110,7 +110,7 @@ static int __init enable_strict_msr_control(char > *str) > } > early_param("ppc_strict_facility_enable", > enable_strict_msr_control); > > -void msr_check_and_set(unsigned long bits) > +unsigned long msr_check_and_set(unsigned long bits) > { > unsigned long oldmsr = mfmsr(); > unsigned long newmsr; > @@ -124,6 +124,8 @@ void msr_check_and_set(unsigned long bits) > > if (oldmsr != newmsr) > mtmsr_isync(newmsr); > + > + return newmsr; > } > > void __msr_check_and_clear(unsigned long bits)
On Wed, 2016-08-17 at 13:43 +1000, Cyril Bur wrote: > mfmsr() is a fairly expensive call and callers of msr_check_and_set() > may want to make decisions bits in the MSR that it did not change but > may not know the value of. I can't grok this. Please reword. Mikey > This patch would avoid a two calls to mfmsr(). > > Signed-off-by: Cyril Bur <cyrilbur@gmail.com> > --- > arch/powerpc/include/asm/reg.h | 2 +- > arch/powerpc/kernel/process.c | 4 +++- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/include/asm/reg.h > b/arch/powerpc/include/asm/reg.h > index f69f40f..0a3dde9 100644 > --- a/arch/powerpc/include/asm/reg.h > +++ b/arch/powerpc/include/asm/reg.h > @@ -1247,7 +1247,7 @@ static inline void mtmsr_isync(unsigned long val) > : "memory") > #endif > > -extern void msr_check_and_set(unsigned long bits); > +extern unsigned long msr_check_and_set(unsigned long bits); > extern bool strict_msr_control; > extern void __msr_check_and_clear(unsigned long bits); > static inline void msr_check_and_clear(unsigned long bits) > diff --git a/arch/powerpc/kernel/process.c > b/arch/powerpc/kernel/process.c > index 82308fd..c42581b 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -110,7 +110,7 @@ static int __init enable_strict_msr_control(char > *str) > } > early_param("ppc_strict_facility_enable", enable_strict_msr_control); > > -void msr_check_and_set(unsigned long bits) > +unsigned long msr_check_and_set(unsigned long bits) > { > unsigned long oldmsr = mfmsr(); > unsigned long newmsr; > @@ -124,6 +124,8 @@ void msr_check_and_set(unsigned long bits) > > if (oldmsr != newmsr) > mtmsr_isync(newmsr); > + > + return newmsr; > } > > void __msr_check_and_clear(unsigned long bits)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index f69f40f..0a3dde9 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -1247,7 +1247,7 @@ static inline void mtmsr_isync(unsigned long val) : "memory") #endif -extern void msr_check_and_set(unsigned long bits); +extern unsigned long msr_check_and_set(unsigned long bits); extern bool strict_msr_control; extern void __msr_check_and_clear(unsigned long bits); static inline void msr_check_and_clear(unsigned long bits) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 82308fd..c42581b 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -110,7 +110,7 @@ static int __init enable_strict_msr_control(char *str) } early_param("ppc_strict_facility_enable", enable_strict_msr_control); -void msr_check_and_set(unsigned long bits) +unsigned long msr_check_and_set(unsigned long bits) { unsigned long oldmsr = mfmsr(); unsigned long newmsr; @@ -124,6 +124,8 @@ void msr_check_and_set(unsigned long bits) if (oldmsr != newmsr) mtmsr_isync(newmsr); + + return newmsr; } void __msr_check_and_clear(unsigned long bits)
mfmsr() is a fairly expensive call and callers of msr_check_and_set() may want to make decisions bits in the MSR that it did not change but may not know the value of. This patch would avoid a two calls to mfmsr(). Signed-off-by: Cyril Bur <cyrilbur@gmail.com> --- arch/powerpc/include/asm/reg.h | 2 +- arch/powerpc/kernel/process.c | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-)