x86/vdso: Fix lsl operand order

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: 6860db30a8fd ("x86/vdso: Use RDPID in preference to LSL when available")
Signed-off-by: Samuel Neves <sneves@dei.uc.pt>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180901201452.27828-1-sneves@dei.uc.pt

diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index fb856c9f04494b6633d9ea8fd3ebb9204cc2c620..53748541c487ab00d8bd1ee9b4d05305aa33171d 100644 (file)
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -93,7 +93,7 @@ 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));