Mark "%rcx" as clobbered by "rdtscp".
This fixes GCE boot for kernel built by clang 11 which uses registers
more aggressively than gcc or clang 10.
@@ -32,7 +32,7 @@ static inline u64
_rdtscp(void)
{
u32 a, d;
- asm volatile("rdtscp" : "=a" (a), "=d" (d));
+ asm volatile("rdtscp" : "=a" (a), "=d" (d) :: "%rcx");
return (((u64)a) | (((u64)d) << 32));
}
