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authorIngo Molnar <mingo@elte.hu>2009-10-13 09:31:28 +0200
committerIngo Molnar <mingo@elte.hu>2009-10-13 09:31:34 +0200
commit9dbdd6c41c12fb42ee7188eafa7e1917b192af3a (patch)
tree06a9eb894bc976c5c20e84ccd74fd82b9b71aed4 /arch/x86/lib/cmpxchg8b_emu.S
parent7a693d3f0d10f978ebdf3082c41404ab97106567 (diff)
parent161291396e76e0832c08f617eb9bd364d1648148 (diff)
Merge commit 'v2.6.32-rc4' into perf/core
Merge reason: we were on an -rc1 base, merge up to -rc4. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/cmpxchg8b_emu.S')
-rw-r--r--arch/x86/lib/cmpxchg8b_emu.S57
1 files changed, 57 insertions, 0 deletions
diff --git a/arch/x86/lib/cmpxchg8b_emu.S b/arch/x86/lib/cmpxchg8b_emu.S
new file mode 100644
index 00000000000..828cb710dec
--- /dev/null
+++ b/arch/x86/lib/cmpxchg8b_emu.S
@@ -0,0 +1,57 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ *
+ */
+
+#include <linux/linkage.h>
+#include <asm/alternative-asm.h>
+#include <asm/frame.h>
+#include <asm/dwarf2.h>
+
+
+.text
+
+/*
+ * 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
+ */
+ENTRY(cmpxchg8b_emu)
+CFI_STARTPROC
+
+#
+# Emulate 'cmpxchg8b (%esi)' on UP except we don't
+# set the whole ZF thing (caller will just compare
+# eax:edx with the expected value)
+#
+cmpxchg8b_emu:
+ pushfl
+ cli
+
+ cmpl (%esi), %eax
+ jne not_same
+ cmpl 4(%esi), %edx
+ jne half_same
+
+ movl %ebx, (%esi)
+ movl %ecx, 4(%esi)
+
+ popfl
+ ret
+
+ not_same:
+ movl (%esi), %eax
+ half_same:
+ movl 4(%esi), %edx
+
+ popfl
+ ret
+
+CFI_ENDPROC
+ENDPROC(cmpxchg8b_emu)