Commit-ID: b08ee5f7e4135d64b8edd769367f8964a725122e Gitweb: http://git.kernel.org/tip/b08ee5f7e4135d64b8edd769367f8964a725122e Author: Borislav Petkov <b...@suse.de> AuthorDate: Fri, 11 Jul 2014 12:43:38 +0200 Committer: H. Peter Anvin <h...@linux.intel.com> CommitDate: Fri, 11 Jul 2014 17:28:51 -0700
x86: Simplify __HAVE_ARCH_CMPXCHG tests Both the 32-bit and 64-bit cmpxchg.h header define __HAVE_ARCH_CMPXCHG and there's ifdeffery which checks it. But since both bitness define it, we can just as well move it up to the main cmpxchg header and simpify a bit of code in doing that. Signed-off-by: Borislav Petkov <b...@suse.de> Link: http://lkml.kernel.org/r/20140711104338.gb17...@pd.tnic Signed-off-by: H. Peter Anvin <h...@linux.intel.com> --- arch/x86/include/asm/cmpxchg.h | 4 ++-- arch/x86/include/asm/cmpxchg_32.h | 2 -- arch/x86/include/asm/cmpxchg_64.h | 2 -- arch/x86/include/asm/mc146818rtc.h | 2 +- arch/x86/include/asm/mutex_32.h | 16 ++-------------- arch/x86/kernel/acpi/boot.c | 4 ---- 6 files changed, 5 insertions(+), 25 deletions(-) diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h index d47786a..99c105d7 100644 --- a/arch/x86/include/asm/cmpxchg.h +++ b/arch/x86/include/asm/cmpxchg.h @@ -4,6 +4,8 @@ #include <linux/compiler.h> #include <asm/alternative.h> /* Provides LOCK_PREFIX */ +#define __HAVE_ARCH_CMPXCHG 1 + /* * Non-existant functions to indicate usage errors at link time * (or compile-time if the compiler implements __compiletime_error(). @@ -143,7 +145,6 @@ extern void __add_wrong_size(void) # include <asm/cmpxchg_64.h> #endif -#ifdef __HAVE_ARCH_CMPXCHG #define cmpxchg(ptr, old, new) \ __cmpxchg(ptr, old, new, sizeof(*(ptr))) @@ -152,7 +153,6 @@ extern void __add_wrong_size(void) #define cmpxchg_local(ptr, old, new) \ __cmpxchg_local(ptr, old, new, sizeof(*(ptr))) -#endif /* * xadd() adds "inc" to "*ptr" and atomically returns the previous diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h index f8bf2ee..f7e1429 100644 --- a/arch/x86/include/asm/cmpxchg_32.h +++ b/arch/x86/include/asm/cmpxchg_32.h @@ -34,8 +34,6 @@ static inline void set_64bit(volatile u64 *ptr, u64 value) : "memory"); } -#define __HAVE_ARCH_CMPXCHG 1 - #ifdef CONFIG_X86_CMPXCHG64 #define cmpxchg64(ptr, o, n) \ ((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \ diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h index 614be87..1af9469 100644 --- a/arch/x86/include/asm/cmpxchg_64.h +++ b/arch/x86/include/asm/cmpxchg_64.h @@ -6,8 +6,6 @@ static inline void set_64bit(volatile u64 *ptr, u64 val) *ptr = val; } -#define __HAVE_ARCH_CMPXCHG 1 - #define cmpxchg64(ptr, o, n) \ ({ \ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ diff --git a/arch/x86/include/asm/mc146818rtc.h b/arch/x86/include/asm/mc146818rtc.h index a55c7ef..0f555cc 100644 --- a/arch/x86/include/asm/mc146818rtc.h +++ b/arch/x86/include/asm/mc146818rtc.h @@ -13,7 +13,7 @@ #define RTC_ALWAYS_BCD 1 /* RTC operates in binary mode */ #endif -#if defined(CONFIG_X86_32) && defined(__HAVE_ARCH_CMPXCHG) +#if defined(CONFIG_X86_32) /* * This lock provides nmi access to the CMOS/RTC registers. It has some * special properties. It is owned by a CPU and stores the index register diff --git a/arch/x86/include/asm/mutex_32.h b/arch/x86/include/asm/mutex_32.h index 0208c3c..85e6cda 100644 --- a/arch/x86/include/asm/mutex_32.h +++ b/arch/x86/include/asm/mutex_32.h @@ -100,23 +100,11 @@ do { \ static inline int __mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *)) { - /* - * We have two variants here. The cmpxchg based one is the best one - * because it never induce a false contention state. It is included - * here because architectures using the inc/dec algorithms over the - * xchg ones are much more likely to support cmpxchg natively. - * - * If not we fall back to the spinlock based variant - that is - * just as efficient (and simpler) as a 'destructive' probing of - * the mutex state would be. - */ -#ifdef __HAVE_ARCH_CMPXCHG + /* cmpxchg because it never induces a false contention state. */ if (likely(atomic_cmpxchg(count, 1, 0) == 1)) return 1; + return 0; -#else - return fail_fn(count); -#endif } #endif /* _ASM_X86_MUTEX_32_H */ diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 86281ff..a531f65 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -74,10 +74,6 @@ int acpi_fix_pin2_polarity __initdata; static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; #endif -#ifndef __HAVE_ARCH_CMPXCHG -#warning ACPI uses CMPXCHG, i486 and later hardware -#endif - /* -------------------------------------------------------------------------- Boot-time Configuration -------------------------------------------------------------------------- */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
