From: Samuel Neves <sneves@xxxxxxxxx>
commit e78e5a91456fcecaa2efbb3706572fe043766f4d upstream.
In the __getcpu function, lsl is using the wrong target and destination
registers. Luckily, the compiler tends to choose %eax for both variables,
so it has been working so far.
Fixes: a582c540ac1b ("x86/vdso: Use RDPID in preference to LSL when available")
Signed-off-by: Samuel Neves <sneves@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20180901201452.27828-1-sneves@xxxxxxxxx
Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/vgtod.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -92,7 +92,7 @@ static inline unsigned int __getcpu(void
*
* If RDPID is available, use it.
*/
- alternative_io ("lsl %[p],%[seg]",
+ alternative_io ("lsl %[seg],%[p]",
".byte 0xf3,0x0f,0xc7,0xf8", /* RDPID %eax/rax */
X86_FEATURE_RDPID,
[p] "=a" (p), [seg] "r" (__PER_CPU_SEG));
