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-rw-r--r--arch/x86/kernel/cpu/intel.c17
-rw-r--r--include/asm-x86/cmpxchg_32.h122
2 files changed, 96 insertions, 43 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index cc8c501b9f3..867ff94579b 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -342,5 +342,22 @@ 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
+
// arch_initcall(intel_cpu_init);
diff --git a/include/asm-x86/cmpxchg_32.h b/include/asm-x86/cmpxchg_32.h
index f86ede28f6d..cea1dae288a 100644
--- a/include/asm-x86/cmpxchg_32.h
+++ b/include/asm-x86/cmpxchg_32.h
@@ -105,15 +105,24 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
#ifdef CONFIG_X86_CMPXCHG
#define __HAVE_ARCH_CMPXCHG 1
-#define cmpxchg(ptr,o,n)\
- ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
- (unsigned long)(n),sizeof(*(ptr))))
-#define sync_cmpxchg(ptr,o,n)\
- ((__typeof__(*(ptr)))__sync_cmpxchg((ptr),(unsigned long)(o),\
- (unsigned long)(n),sizeof(*(ptr))))
-#define cmpxchg_local(ptr,o,n)\
- ((__typeof__(*(ptr)))__cmpxchg_local((ptr),(unsigned long)(o),\
- (unsigned long)(n),sizeof(*(ptr))))
+#define cmpxchg(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr))))
+#define sync_cmpxchg(ptr, o, n) \
+ ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr))))
+#define cmpxchg_local(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr))))
+#endif
+
+#ifdef CONFIG_X86_CMPXCHG64
+#define cmpxchg64(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \
+ (unsigned long long)(n)))
+#define cmpxchg64_local(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg64_local((ptr), (unsigned long long)(o),\
+ (unsigned long long)(n)))
#endif
static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
@@ -203,6 +212,34 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
return old;
}
+static inline unsigned long long __cmpxchg64(volatile void *ptr,
+ unsigned long long old, unsigned long long new)
+{
+ unsigned long long prev;
+ __asm__ __volatile__(LOCK_PREFIX "cmpxchg8b %3"
+ : "=A"(prev)
+ : "b"((unsigned long)new),
+ "c"((unsigned long)(new >> 32)),
+ "m"(*__xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+}
+
+static inline unsigned long long __cmpxchg64_local(volatile void *ptr,
+ unsigned long long old, unsigned long long new)
+{
+ unsigned long long prev;
+ __asm__ __volatile__("cmpxchg8b %3"
+ : "=A"(prev)
+ : "b"((unsigned long)new),
+ "c"((unsigned long)(new >> 32)),
+ "m"(*__xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+}
+
#ifndef CONFIG_X86_CMPXCHG
/*
* Building a kernel capable running on 80386. It may be necessary to
@@ -228,7 +265,7 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
return old;
}
-#define cmpxchg(ptr,o,n) \
+#define cmpxchg(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
if (likely(boot_cpu_data.x86 > 3)) \
@@ -239,7 +276,7 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
(unsigned long)(n), sizeof(*(ptr))); \
__ret; \
})
-#define cmpxchg_local(ptr,o,n) \
+#define cmpxchg_local(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
if (likely(boot_cpu_data.x86 > 3)) \
@@ -252,38 +289,37 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
})
#endif
-static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long long old,
- unsigned long long new)
-{
- unsigned long long prev;
- __asm__ __volatile__(LOCK_PREFIX "cmpxchg8b %3"
- : "=A"(prev)
- : "b"((unsigned long)new),
- "c"((unsigned long)(new >> 32)),
- "m"(*__xg(ptr)),
- "0"(old)
- : "memory");
- return prev;
-}
+#ifndef CONFIG_X86_CMPXCHG64
+/*
+ * Building a kernel capable running on 80386 and 80486. It may be necessary
+ * to simulate the cmpxchg8b on the 80386 and 80486 CPU.
+ */
-static inline unsigned long long __cmpxchg64_local(volatile void *ptr,
- unsigned long long old, unsigned long long new)
-{
- unsigned long long prev;
- __asm__ __volatile__("cmpxchg8b %3"
- : "=A"(prev)
- : "b"((unsigned long)new),
- "c"((unsigned long)(new >> 32)),
- "m"(*__xg(ptr)),
- "0"(old)
- : "memory");
- return prev;
-}
+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 = __cmpxchg64((ptr), (unsigned long long)(o), \
+ (unsigned long long)(n)); \
+ else \
+ __ret = cmpxchg_486_u64((ptr), (unsigned long long)(o), \
+ (unsigned long long)(n)); \
+ __ret; \
+})
+#define cmpxchg64_local(ptr, o, n) \
+({ \
+ __typeof__(*(ptr)) __ret; \
+ if (likely(boot_cpu_data.x86 > 4)) \
+ __ret = __cmpxchg64_local((ptr), (unsigned long long)(o), \
+ (unsigned long long)(n)); \
+ else \
+ __ret = cmpxchg_486_u64((ptr), (unsigned long long)(o), \
+ (unsigned long long)(n)); \
+ __ret; \
+})
+
+#endif
-#define cmpxchg64(ptr,o,n)\
- ((__typeof__(*(ptr)))__cmpxchg64((ptr),(unsigned long long)(o),\
- (unsigned long long)(n)))
-#define cmpxchg64_local(ptr,o,n)\
- ((__typeof__(*(ptr)))__cmpxchg64_local((ptr),(unsigned long long)(o),\
- (unsigned long long)(n)))
#endif
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-26 10:52:51 +0000