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 <redacted>
---
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)
--
2.9.3