diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-30 15:10:40 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-30 15:10:40 -0700 |
commit | 84d88d5d4efc37dfb8a93a4a58d8a227ee86ffa4 (patch) | |
tree | 8dc2761f3111a7dfee01f290f2659faaa24ec06e | |
parent | e399835c349b7d8339775a004a86a492a444e230 (diff) | |
parent | 152f9d0710a62708710161bce1b29fa8292c8c11 (diff) | |
download | kernel_samsung_tuna-84d88d5d4efc37dfb8a93a4a58d8a227ee86ffa4.zip kernel_samsung_tuna-84d88d5d4efc37dfb8a93a4a58d8a227ee86ffa4.tar.gz kernel_samsung_tuna-84d88d5d4efc37dfb8a93a4a58d8a227ee86ffa4.tar.bz2 |
Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched_clock: Fix atomicity/continuity bug by using cmpxchg64()
x86: Provide an alternative() based cmpxchg64()
-rw-r--r-- | arch/x86/include/asm/cmpxchg_32.h | 30 | ||||
-rw-r--r-- | arch/x86/kernel/i386_ksyms_32.c | 8 | ||||
-rw-r--r-- | arch/x86/lib/Makefile | 2 | ||||
-rw-r--r-- | arch/x86/lib/cmpxchg8b_emu.S | 57 | ||||
-rw-r--r-- | kernel/sched_clock.c | 4 |
5 files changed, 85 insertions, 16 deletions
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h index 82ceb78..ee1931b 100644 --- a/arch/x86/include/asm/cmpxchg_32.h +++ b/arch/x86/include/asm/cmpxchg_32.h @@ -312,19 +312,23 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old, extern unsigned long long cmpxchg_486_u64(volatile void *, u64, u64); -#define cmpxchg64(ptr, o, n) \ -({ \ - __typeof__(*(ptr)) __ret; \ - if (likely(boot_cpu_data.x86 > 4)) \ - __ret = (__typeof__(*(ptr)))__cmpxchg64((ptr), \ - (unsigned long long)(o), \ - (unsigned long long)(n)); \ - else \ - __ret = (__typeof__(*(ptr)))cmpxchg_486_u64((ptr), \ - (unsigned long long)(o), \ - (unsigned long long)(n)); \ - __ret; \ -}) +#define cmpxchg64(ptr, o, n) \ +({ \ + __typeof__(*(ptr)) __ret; \ + __typeof__(*(ptr)) __old = (o); \ + __typeof__(*(ptr)) __new = (n); \ + alternative_io("call cmpxchg8b_emu", \ + "lock; cmpxchg8b (%%esi)" , \ + X86_FEATURE_CX8, \ + "=A" (__ret), \ + "S" ((ptr)), "0" (__old), \ + "b" ((unsigned int)__new), \ + "c" ((unsigned int)(__new>>32)) \ + : "memory"); \ + __ret; }) + + + #define cmpxchg64_local(ptr, o, n) \ ({ \ __typeof__(*(ptr)) __ret; \ diff --git a/arch/x86/kernel/i386_ksyms_32.c b/arch/x86/kernel/i386_ksyms_32.c index 43cec6b..1736c5a 100644 --- a/arch/x86/kernel/i386_ksyms_32.c +++ b/arch/x86/kernel/i386_ksyms_32.c @@ -10,6 +10,14 @@ EXPORT_SYMBOL(mcount); #endif +/* + * Note, this is a prototype to get at the symbol for + * the export, but dont use it from C code, it is used + * by assembly code and is not using C calling convention! + */ +extern void cmpxchg8b_emu(void); +EXPORT_SYMBOL(cmpxchg8b_emu); + /* Networking helper routines. */ EXPORT_SYMBOL(csum_partial_copy_generic); diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 9e60920..3e549b8 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -15,7 +15,7 @@ ifeq ($(CONFIG_X86_32),y) obj-y += atomic64_32.o lib-y += checksum_32.o lib-y += strstr_32.o - lib-y += semaphore_32.o string_32.o + lib-y += semaphore_32.o string_32.o cmpxchg8b_emu.o lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o else diff --git a/arch/x86/lib/cmpxchg8b_emu.S b/arch/x86/lib/cmpxchg8b_emu.S new file mode 100644 index 0000000..828cb71 --- /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) diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index ac2e1dc..479ce56 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -127,7 +127,7 @@ again: clock = wrap_max(clock, min_clock); clock = wrap_min(clock, max_clock); - if (cmpxchg(&scd->clock, old_clock, clock) != old_clock) + if (cmpxchg64(&scd->clock, old_clock, clock) != old_clock) goto again; return clock; @@ -163,7 +163,7 @@ again: val = remote_clock; } - if (cmpxchg(ptr, old_val, val) != old_val) + if (cmpxchg64(ptr, old_val, val) != old_val) goto again; return val; |