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authorNick Piggin <nickpiggin@yahoo.com.au>2005-11-13 16:07:23 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-13 18:14:15 -0800
commit53e86b91b7ae66d4c2757195cbd42e00d9199cf2 (patch)
tree80c44aeb046ac91a5bc7465da91a7b2519c53096 /arch/i386/kernel/cpu/intel.c
parentdbdf65b1b7f8ec48bda1604cfea7ac09ce583d6b (diff)
[PATCH] i386: generic cmpxchg
- Make cmpxchg generally available on the i386 platform. - Provide emulation of cmpxchg suitable for uniprocessor if built and run on 386. From: Christoph Lameter <clameter@sgi.com> - Cut down patch and small style changes. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel/cpu/intel.c')
-rw-r--r--arch/i386/kernel/cpu/intel.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/intel.c b/arch/i386/kernel/cpu/intel.c
index 43601de0f63..c28d26fb5f2 100644
--- a/arch/i386/kernel/cpu/intel.c
+++ b/arch/i386/kernel/cpu/intel.c
@@ -6,6 +6,7 @@
#include <linux/bitops.h>
#include <linux/smp.h>
#include <linux/thread_info.h>
+#include <linux/module.h>
#include <asm/processor.h>
#include <asm/msr.h>
@@ -264,5 +265,52 @@ __init int intel_cpu_init(void)
return 0;
}
+#ifndef CONFIG_X86_CMPXCHG
+unsigned long cmpxchg_386_u8(volatile void *ptr, u8 old, u8 new)
+{
+ u8 prev;
+ unsigned long flags;
+
+ /* Poor man's cmpxchg for 386. Unsuitable for SMP */
+ local_irq_save(flags);
+ prev = *(u8 *)ptr;
+ if (prev == old)
+ *(u8 *)ptr = new;
+ local_irq_restore(flags);
+ return prev;
+}
+EXPORT_SYMBOL(cmpxchg_386_u8);
+
+unsigned long cmpxchg_386_u16(volatile void *ptr, u16 old, u16 new)
+{
+ u16 prev;
+ unsigned long flags;
+
+ /* Poor man's cmpxchg for 386. Unsuitable for SMP */
+ local_irq_save(flags);
+ prev = *(u16 *)ptr;
+ if (prev == old)
+ *(u16 *)ptr = new;
+ local_irq_restore(flags);
+ return prev;
+}
+EXPORT_SYMBOL(cmpxchg_386_u16);
+
+unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new)
+{
+ u32 prev;
+ unsigned long flags;
+
+ /* Poor man's cmpxchg for 386. Unsuitable for SMP */
+ local_irq_save(flags);
+ prev = *(u32 *)ptr;
+ if (prev == old)
+ *(u32 *)ptr = new;
+ local_irq_restore(flags);
+ return prev;
+}
+EXPORT_SYMBOL(cmpxchg_386_u32);
+#endif
+
// arch_initcall(intel_cpu_init);