The 128-bit multiply in pvclock.h was missing an output constraint for
EDX which caused a register corruption to appear. Thanks to Ulrich for
diagnosing the EDX corruption and Avi for providing this fix (which now
I am sending back to you Avi..)
Zach
>From Avi and Ulrich, fix constraints for 128-bit multiply
Signed-off-by: Zachary Amsden <[email protected]>
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index 31d84ac..a518c0a 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -22,6 +22,8 @@ static inline u64 pvclock_scale_delta(u64 delta, u32
mul_frac, int shift)
u64 product;
#ifdef __i386__
u32 tmp1, tmp2;
+#else
+ ulong tmp;
#endif
if (shift < 0)
@@ -42,8 +44,11 @@ static inline u64 pvclock_scale_delta(u64 delta, u32
mul_frac, int shift)
: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
#elif defined(__x86_64__)
__asm__ (
- "mul %%rdx ; shrd $32,%%rdx,%%rax"
- : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
+ "mul %[mul_frac] ; shrd $32, %[hi], %[lo]"
+ : [lo]"=a"(product),
+ [hi]"=d"(tmp)
+ : "0"(delta),
+ [mul_frac]"rm"((u64)mul_frac));
#else
#error implement me!
#endif
