Add a cast in case the caller passes in a different type, as it would
if mtspr/mtmsr were functions.
Previously, if a 64-bit type was passed in on 32-bit, GCC would bind the
constraint to a pair of registers, and would substitute the first register
in the pair in the asm code. This corresponds to the upper half of the
64-bit register, which is generally not the desired behavior.
Signed-off-by: Scott Wood <scottw...@freescale.com>
---
If you're wondering why you'd pass a 64-bit value to one of these macros
on 32-bit, it came up when trying to load an SPR from kvm_vcpu_arch_shared.
arch/powerpc/include/asm/reg.h | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 213d1d7..1b45133 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1007,13 +1007,16 @@
#define mtmsrd(v) __mtmsrd((v), 0)
#define mtmsr(v) mtmsrd(v)
#else
-#define mtmsr(v) asm volatile("mtmsr %0" : : "r" (v) : "memory")
+#define mtmsr(v) asm volatile("mtmsr %0" : \
+ : "r" ((unsigned long)(v)) \
+ : "memory")
#endif
#define mfspr(rn) ({unsigned long rval; \
asm volatile("mfspr %0," __stringify(rn) \
: "=r" (rval)); rval;})
-#define mtspr(rn, v) asm volatile("mtspr " __stringify(rn) ",%0" : : "r" (v)\
+#define mtspr(rn, v) asm volatile("mtspr " __stringify(rn) ",%0" : \
+ : "r" ((unsigned long)(v)) \
: "memory")
#ifdef __powerpc64__
--
1.7.4.1
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