Commit d7c3f8ce authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds

percpu: Omit segment prefix in the UP case for cmpxchg_double

Omit the segment prefix in the UP case. GS is not used then
and we will generate segfaults if cmpxchg16b is used otherwise.
Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 76597cd3
...@@ -45,7 +45,7 @@ ...@@ -45,7 +45,7 @@
#include <linux/stringify.h> #include <linux/stringify.h>
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
#define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x #define __percpu_prefix "%%"__stringify(__percpu_seg)":"
#define __my_cpu_offset percpu_read(this_cpu_off) #define __my_cpu_offset percpu_read(this_cpu_off)
/* /*
...@@ -62,9 +62,11 @@ ...@@ -62,9 +62,11 @@
(typeof(*(ptr)) __kernel __force *)tcp_ptr__; \ (typeof(*(ptr)) __kernel __force *)tcp_ptr__; \
}) })
#else #else
#define __percpu_arg(x) "%P" #x #define __percpu_prefix ""
#endif #endif
#define __percpu_arg(x) __percpu_prefix "%P" #x
/* /*
* Initialized pointers to per-cpu variables needed for the boot * Initialized pointers to per-cpu variables needed for the boot
* processor need to use these macros to get the proper address * processor need to use these macros to get the proper address
...@@ -516,11 +518,11 @@ do { \ ...@@ -516,11 +518,11 @@ do { \
typeof(o2) __n2 = n2; \ typeof(o2) __n2 = n2; \
typeof(o2) __dummy; \ typeof(o2) __dummy; \
alternative_io("call this_cpu_cmpxchg16b_emu\n\t" P6_NOP4, \ alternative_io("call this_cpu_cmpxchg16b_emu\n\t" P6_NOP4, \
"cmpxchg16b %%gs:(%%rsi)\n\tsetz %0\n\t", \ "cmpxchg16b " __percpu_prefix "(%%rsi)\n\tsetz %0\n\t", \
X86_FEATURE_CX16, \ X86_FEATURE_CX16, \
ASM_OUTPUT2("=a"(__ret), "=d"(__dummy)), \ ASM_OUTPUT2("=a"(__ret), "=d"(__dummy)), \
"S" (&pcp1), "b"(__n1), "c"(__n2), \ "S" (&pcp1), "b"(__n1), "c"(__n2), \
"a"(__o1), "d"(__o2)); \ "a"(__o1), "d"(__o2) : "memory"); \
__ret; \ __ret; \
}) })
......
...@@ -10,6 +10,12 @@ ...@@ -10,6 +10,12 @@
#include <asm/frame.h> #include <asm/frame.h>
#include <asm/dwarf2.h> #include <asm/dwarf2.h>
#ifdef CONFIG_SMP
#define SEG_PREFIX %gs:
#else
#define SEG_PREFIX
#endif
.text .text
/* /*
...@@ -37,13 +43,13 @@ this_cpu_cmpxchg16b_emu: ...@@ -37,13 +43,13 @@ this_cpu_cmpxchg16b_emu:
pushf pushf
cli cli
cmpq %gs:(%rsi), %rax cmpq SEG_PREFIX(%rsi), %rax
jne not_same jne not_same
cmpq %gs:8(%rsi), %rdx cmpq SEG_PREFIX 8(%rsi), %rdx
jne not_same jne not_same
movq %rbx, %gs:(%rsi) movq %rbx, SEG_PREFIX(%rsi)
movq %rcx, %gs:8(%rsi) movq %rcx, SEG_PREFIX 8(%rsi)
popf popf
mov $1, %al mov $1, %al
......
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