x86, asm: Merge cmpxchg_486_u64() and cmpxchg8b_emu()

We have two functions for doing exactly the same thing -- emulating
cmpxchg8b on 486 and older hardware -- with different calling
conventions, and yet doing the same thing.  Drop the C version and use
the assembly version, via alternatives, for both the local and
non-local versions of cmpxchg8b.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <AANLkTikAmaDPji-TVDarmG1yD=fwbffcsmEU=YEuP+8r@mail.gmail.com>

1 files changed, 0 insertions, 18 deletions

diff --git a/arch/x86/lib/cmpxchg.c b/arch/x86/lib/cmpxchg.c
index 2056ccf572cc..5d619f6df3ee 100644
--- a/arch/x86/lib/cmpxchg.c
+++ b/arch/x86/lib/cmpxchg.c
@@ -52,21 +52,3 @@ unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new)
 }
 EXPORT_SYMBOL(cmpxchg_386_u32);
 #endif
-
-#ifndef CONFIG_X86_CMPXCHG64
-unsigned long long cmpxchg_486_u64(volatile void *ptr, u64 old, u64 new)
-{
-        u64 prev;
-        unsigned long flags;
-
-        /* Poor man's cmpxchg8b for 386 and 486. Unsuitable for SMP */
-        local_irq_save(flags);
-        prev = *(u64 *)ptr;
-        if (prev == old)
-                *(u64 *)ptr = new;
-        local_irq_restore(flags);
-        return prev;
-}
-EXPORT_SYMBOL(cmpxchg_486_u64);
-#endif
-