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Diffstat (limited to 'arch/x86/lib/cmpxchg8b_emu.S')
-rw-r--r--arch/x86/lib/cmpxchg8b_emu.S30
1 files changed, 21 insertions, 9 deletions
diff --git a/arch/x86/lib/cmpxchg8b_emu.S b/arch/x86/lib/cmpxchg8b_emu.S
index 873e4ef23e..1c96be769a 100644
--- a/arch/x86/lib/cmpxchg8b_emu.S
+++ b/arch/x86/lib/cmpxchg8b_emu.S
@@ -24,12 +24,12 @@ SYM_FUNC_START(cmpxchg8b_emu)
pushfl
cli
- cmpl 0(%esi), %eax
+ cmpl (%esi), %eax
jne .Lnot_same
cmpl 4(%esi), %edx
jne .Lnot_same
- movl %ebx, 0(%esi)
+ movl %ebx, (%esi)
movl %ecx, 4(%esi)
orl $X86_EFLAGS_ZF, (%esp)
@@ -38,7 +38,7 @@ SYM_FUNC_START(cmpxchg8b_emu)
RET
.Lnot_same:
- movl 0(%esi), %eax
+ movl (%esi), %eax
movl 4(%esi), %edx
andl $(~X86_EFLAGS_ZF), (%esp)
@@ -53,18 +53,30 @@ EXPORT_SYMBOL(cmpxchg8b_emu)
#ifndef CONFIG_UML
+/*
+ * Emulate 'cmpxchg8b %fs:(%rsi)'
+ *
+ * Inputs:
+ * %esi : memory location to compare
+ * %eax : low 32 bits of old value
+ * %edx : high 32 bits of old value
+ * %ebx : low 32 bits of new value
+ * %ecx : high 32 bits of new value
+ *
+ * Notably this is not LOCK prefixed and is not safe against NMIs
+ */
SYM_FUNC_START(this_cpu_cmpxchg8b_emu)
pushfl
cli
- cmpl PER_CPU_VAR(0(%esi)), %eax
+ cmpl __percpu (%esi), %eax
jne .Lnot_same2
- cmpl PER_CPU_VAR(4(%esi)), %edx
+ cmpl __percpu 4(%esi), %edx
jne .Lnot_same2
- movl %ebx, PER_CPU_VAR(0(%esi))
- movl %ecx, PER_CPU_VAR(4(%esi))
+ movl %ebx, __percpu (%esi)
+ movl %ecx, __percpu 4(%esi)
orl $X86_EFLAGS_ZF, (%esp)
@@ -72,8 +84,8 @@ SYM_FUNC_START(this_cpu_cmpxchg8b_emu)
RET
.Lnot_same2:
- movl PER_CPU_VAR(0(%esi)), %eax
- movl PER_CPU_VAR(4(%esi)), %edx
+ movl __percpu (%esi), %eax
+ movl __percpu 4(%esi), %edx
andl $(~X86_EFLAGS_ZF), (%esp)