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Merge branch 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix LOCK_PREFIX_HERE for uniprocessor build
  x86, atomic64: In selftest, distinguish x86-64 from 586+
  x86-32: Fix atomic64_inc_not_zero return value convention
  lib: Fix atomic64_inc_not_zero test
  lib: Fix atomic64_add_unless return value convention
  x86-32: Fix atomic64_add_unless return value convention
  lib: Fix atomic64_add_unless test
  x86: Implement atomic[64]_dec_if_positive()
  lib: Only test atomic64_dec_if_positive on archs having it
  x86-32: Rewrite 32-bit atomic64 functions in assembly
  lib: Add self-test for atomic64_t
  x86-32: Allow UP/SMP lock replacement in cmpxchg64
  x86: Add support for lock prefix in alternatives
This commit is contained in:
Linus Torvalds 2010-05-18 08:40:05 -07:00
parent 7421a10de7 d9c5841e22
commit 93c9d7f60c
14 changed files with 894 additions and 297 deletions
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9
arch/x86/include/asm/alternative.h
View File

@ -28,14 +28,17 @@
*/
#ifdef CONFIG_SMP
#define LOCK_PREFIX \
#define LOCK_PREFIX_HERE \
".section .smp_locks,\"a\"\n" \
".balign 4\n" \
".long 661f - .\n" /* offset */ \
".long 671f - .\n" /* offset */ \
".previous\n" \
"661:\n\tlock; "
"671:"
#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
#else /* ! CONFIG_SMP */
#define LOCK_PREFIX_HERE ""
#define LOCK_PREFIX ""
#endif

23
arch/x86/include/asm/atomic.h
View File

@ -246,6 +246,29 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
/*
* atomic_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
static inline int atomic_dec_if_positive(atomic_t *v)
{
int c, old, dec;
c = atomic_read(v);
for (;;) {
dec = c - 1;
if (unlikely(dec < 0))
break;
old = atomic_cmpxchg((v), c, dec);
if (likely(old == c))
break;
c = old;
}
return dec;
}
/**
* atomic_inc_short - increment of a short integer
* @v: pointer to type int

278
arch/x86/include/asm/atomic64_32.h
View File

@ -14,109 +14,193 @@ typedef struct {
#define ATOMIC64_INIT(val) { (val) }
extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);
#ifdef CONFIG_X86_CMPXCHG64
#define ATOMIC64_ALTERNATIVE_(f, g) "call atomic64_" #g "_cx8"
#else
#define ATOMIC64_ALTERNATIVE_(f, g) ALTERNATIVE("call atomic64_" #f "_386", "call atomic64_" #g "_cx8", X86_FEATURE_CX8)
#endif
#define ATOMIC64_ALTERNATIVE(f) ATOMIC64_ALTERNATIVE_(f, f)
/**
* atomic64_cmpxchg - cmpxchg atomic64 variable
* @p: pointer to type atomic64_t
* @o: expected value
* @n: new value
*
* Atomically sets @v to @n if it was equal to @o and returns
* the old value.
*/
static inline long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)
{
return cmpxchg64(&v->counter, o, n);
}
/**
* atomic64_xchg - xchg atomic64 variable
* @ptr: pointer to type atomic64_t
* @new_val: value to assign
* @v: pointer to type atomic64_t
* @n: value to assign
*
* Atomically xchgs the value of @ptr to @new_val and returns
* Atomically xchgs the value of @v to @n and returns
* the old value.
*/
extern u64 atomic64_xchg(atomic64_t *ptr, u64 new_val);
static inline long long atomic64_xchg(atomic64_t *v, long long n)
{
long long o;
unsigned high = (unsigned)(n >> 32);
unsigned low = (unsigned)n;
asm volatile(ATOMIC64_ALTERNATIVE(xchg)
: "=A" (o), "+b" (low), "+c" (high)
: "S" (v)
: "memory"
);
return o;
}
/**
* atomic64_set - set atomic64 variable
* @ptr: pointer to type atomic64_t
* @new_val: value to assign
* @v: pointer to type atomic64_t
* @n: value to assign
*
* Atomically sets the value of @ptr to @new_val.
* Atomically sets the value of @v to @n.
*/
extern void atomic64_set(atomic64_t *ptr, u64 new_val);
static inline void atomic64_set(atomic64_t *v, long long i)
{
unsigned high = (unsigned)(i >> 32);
unsigned low = (unsigned)i;
asm volatile(ATOMIC64_ALTERNATIVE(set)
: "+b" (low), "+c" (high)
: "S" (v)
: "eax", "edx", "memory"
);
}
/**
* atomic64_read - read atomic64 variable
* @ptr: pointer to type atomic64_t
* @v: pointer to type atomic64_t
*
* Atomically reads the value of @ptr and returns it.
* Atomically reads the value of @v and returns it.
*/
static inline u64 atomic64_read(atomic64_t *ptr)
static inline long long atomic64_read(atomic64_t *v)
{
u64 res;
/*
* Note, we inline this atomic64_t primitive because
* it only clobbers EAX/EDX and leaves the others
* untouched. We also (somewhat subtly) rely on the
* fact that cmpxchg8b returns the current 64-bit value
* of the memory location we are touching:
*/
asm volatile(
"mov %%ebx, %%eax\n\t"
"mov %%ecx, %%edx\n\t"
LOCK_PREFIX "cmpxchg8b %1\n"
: "=&A" (res)
: "m" (*ptr)
);
return res;
}
extern u64 atomic64_read(atomic64_t *ptr);
long long r;
asm volatile(ATOMIC64_ALTERNATIVE(read)
: "=A" (r), "+c" (v)
: : "memory"
);
return r;
}
/**
* atomic64_add_return - add and return
* @delta: integer value to add
* @ptr: pointer to type atomic64_t
* @i: integer value to add
* @v: pointer to type atomic64_t
*
* Atomically adds @delta to @ptr and returns @delta + *@ptr
* Atomically adds @i to @v and returns @i + *@v
*/
extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);
static inline long long atomic64_add_return(long long i, atomic64_t *v)
{
asm volatile(ATOMIC64_ALTERNATIVE(add_return)
: "+A" (i), "+c" (v)
: : "memory"
);
return i;
}
/*
* Other variants with different arithmetic operators:
*/
extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);
extern u64 atomic64_inc_return(atomic64_t *ptr);
extern u64 atomic64_dec_return(atomic64_t *ptr);
static inline long long atomic64_sub_return(long long i, atomic64_t *v)
{
asm volatile(ATOMIC64_ALTERNATIVE(sub_return)
: "+A" (i), "+c" (v)
: : "memory"
);
return i;
}
static inline long long atomic64_inc_return(atomic64_t *v)
{
long long a;
asm volatile(ATOMIC64_ALTERNATIVE(inc_return)
: "=A" (a)
: "S" (v)
: "memory", "ecx"
);
return a;
}
static inline long long atomic64_dec_return(atomic64_t *v)
{
long long a;
asm volatile(ATOMIC64_ALTERNATIVE(dec_return)
: "=A" (a)
: "S" (v)
: "memory", "ecx"
);
return a;
}
/**
* atomic64_add - add integer to atomic64 variable
* @delta: integer value to add
* @ptr: pointer to type atomic64_t
* @i: integer value to add
* @v: pointer to type atomic64_t
*
* Atomically adds @delta to @ptr.
* Atomically adds @i to @v.
*/
extern void atomic64_add(u64 delta, atomic64_t *ptr);
static inline long long atomic64_add(long long i, atomic64_t *v)
{
asm volatile(ATOMIC64_ALTERNATIVE_(add, add_return)
: "+A" (i), "+c" (v)
: : "memory"
);
return i;
}
/**
* atomic64_sub - subtract the atomic64 variable
* @delta: integer value to subtract
* @ptr: pointer to type atomic64_t
* @i: integer value to subtract
* @v: pointer to type atomic64_t
*
* Atomically subtracts @delta from @ptr.
* Atomically subtracts @i from @v.
*/
extern void atomic64_sub(u64 delta, atomic64_t *ptr);
static inline long long atomic64_sub(long long i, atomic64_t *v)
{
asm volatile(ATOMIC64_ALTERNATIVE_(sub, sub_return)
: "+A" (i), "+c" (v)
: : "memory"
);
return i;
}
/**
* atomic64_sub_and_test - subtract value from variable and test result
* @delta: integer value to subtract
* @ptr: pointer to type atomic64_t
*
* Atomically subtracts @delta from @ptr and returns
* @i: integer value to subtract
* @v: pointer to type atomic64_t
*
* Atomically subtracts @i from @v and returns
* true if the result is zero, or false for all
* other cases.
*/
extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);
static inline int atomic64_sub_and_test(long long i, atomic64_t *v)
{
return atomic64_sub_return(i, v) == 0;
}
/**
* atomic64_inc - increment atomic64 variable
* @ptr: pointer to type atomic64_t
* @v: pointer to type atomic64_t
*
* Atomically increments @ptr by 1.
* Atomically increments @v by 1.
*/
extern void atomic64_inc(atomic64_t *ptr);
static inline void atomic64_inc(atomic64_t *v)
{
asm volatile(ATOMIC64_ALTERNATIVE_(inc, inc_return)
: : "S" (v)
: "memory", "eax", "ecx", "edx"
);
}
/**
* atomic64_dec - decrement atomic64 variable
@ -124,37 +208,97 @@ extern void atomic64_inc(atomic64_t *ptr);
*
* Atomically decrements @ptr by 1.
*/
extern void atomic64_dec(atomic64_t *ptr);
static inline void atomic64_dec(atomic64_t *v)
{
asm volatile(ATOMIC64_ALTERNATIVE_(dec, dec_return)
: : "S" (v)
: "memory", "eax", "ecx", "edx"
);
}
/**
* atomic64_dec_and_test - decrement and test
* @ptr: pointer to type atomic64_t
* @v: pointer to type atomic64_t
*
* Atomically decrements @ptr by 1 and
* Atomically decrements @v by 1 and
* returns true if the result is 0, or false for all other
* cases.
*/
extern int atomic64_dec_and_test(atomic64_t *ptr);
static inline int atomic64_dec_and_test(atomic64_t *v)
{
return atomic64_dec_return(v) == 0;
}
/**
* atomic64_inc_and_test - increment and test
* @ptr: pointer to type atomic64_t
* @v: pointer to type atomic64_t
*
* Atomically increments @ptr by 1
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
extern int atomic64_inc_and_test(atomic64_t *ptr);
static inline int atomic64_inc_and_test(atomic64_t *v)
{
return atomic64_inc_return(v) == 0;
}
/**
* atomic64_add_negative - add and test if negative
* @delta: integer value to add
* @ptr: pointer to type atomic64_t
* @i: integer value to add
* @v: pointer to type atomic64_t
*
* Atomically adds @delta to @ptr and returns true
* Atomically adds @i to @v and returns true
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);
static inline int atomic64_add_negative(long long i, atomic64_t *v)
{
return atomic64_add_return(i, v) < 0;
}
/**
* atomic64_add_unless - add unless the number is a given value
* @v: pointer of type atomic64_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as it was not @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u)
{
unsigned low = (unsigned)u;
unsigned high = (unsigned)(u >> 32);
asm volatile(ATOMIC64_ALTERNATIVE(add_unless) "\n\t"
: "+A" (a), "+c" (v), "+S" (low), "+D" (high)
: : "memory");
return (int)a;
}
static inline int atomic64_inc_not_zero(atomic64_t *v)
{
int r;
asm volatile(ATOMIC64_ALTERNATIVE(inc_not_zero)
: "=a" (r)
: "S" (v)
: "ecx", "edx", "memory"
);
return r;
}
static inline long long atomic64_dec_if_positive(atomic64_t *v)
{
long long r;
asm volatile(ATOMIC64_ALTERNATIVE(dec_if_positive)
: "=A" (r)
: "S" (v)
: "ecx", "memory"
);
return r;
}
#undef ATOMIC64_ALTERNATIVE
#undef ATOMIC64_ALTERNATIVE_
#endif /* _ASM_X86_ATOMIC64_32_H */

23
arch/x86/include/asm/atomic64_64.h
View File

@ -221,4 +221,27 @@ static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
/*
* atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
static inline long atomic64_dec_if_positive(atomic64_t *v)
{
long c, old, dec;
c = atomic64_read(v);
for (;;) {
dec = c - 1;
if (unlikely(dec < 0))
break;
old = atomic64_cmpxchg((v), c, dec);
if (likely(old == c))
break;
c = old;
}
return dec;
}
#endif /* _ASM_X86_ATOMIC64_64_H */

3
arch/x86/include/asm/cmpxchg_32.h
View File

@ -271,7 +271,8 @@ extern unsigned long long cmpxchg_486_u64(volatile void *, u64, u64);
__typeof__(*(ptr)) __ret; \
__typeof__(*(ptr)) __old = (o); \
__typeof__(*(ptr)) __new = (n); \
alternative_io("call cmpxchg8b_emu", \
alternative_io(LOCK_PREFIX_HERE \
"call cmpxchg8b_emu", \
"lock; cmpxchg8b (%%esi)" , \
X86_FEATURE_CX8, \
"=A" (__ret), \

6
arch/x86/kernel/alternative.c
View File

@ -247,7 +247,8 @@ static void alternatives_smp_lock(const s32 *start, const s32 *end,
if (!*poff || ptr < text || ptr >= text_end)
continue;
/* turn DS segment override prefix into lock prefix */
text_poke(ptr, ((unsigned char []){0xf0}), 1);
if (*ptr == 0x3e)
text_poke(ptr, ((unsigned char []){0xf0}), 1);
};
mutex_unlock(&text_mutex);
}
@ -267,7 +268,8 @@ static void alternatives_smp_unlock(const s32 *start, const s32 *end,
if (!*poff || ptr < text || ptr >= text_end)
continue;
/* turn lock prefix into DS segment override prefix */
text_poke(ptr, ((unsigned char []){0x3E}), 1);
if (*ptr == 0xf0)
text_poke(ptr, ((unsigned char []){0x3E}), 1);
};
mutex_unlock(&text_mutex);
}

3
arch/x86/lib/Makefile
View File

@ -26,11 +26,12 @@ obj-y += msr.o msr-reg.o msr-reg-export.o
ifeq ($(CONFIG_X86_32),y)
obj-y += atomic64_32.o
lib-y += atomic64_cx8_32.o
lib-y += checksum_32.o
lib-y += strstr_32.o
lib-y += semaphore_32.o string_32.o
ifneq ($(CONFIG_X86_CMPXCHG64),y)
lib-y += cmpxchg8b_emu.o
lib-y += cmpxchg8b_emu.o atomic64_386_32.o
endif
lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o
else

271
arch/x86/lib/atomic64_32.c
View File

@ -6,225 +6,54 @@
#include <asm/cmpxchg.h>
#include <asm/atomic.h>
static noinline u64 cmpxchg8b(u64 *ptr, u64 old, u64 new)
{
u32 low = new;
u32 high = new >> 32;
long long atomic64_read_cx8(long long, const atomic64_t *v);
EXPORT_SYMBOL(atomic64_read_cx8);
long long atomic64_set_cx8(long long, const atomic64_t *v);
EXPORT_SYMBOL(atomic64_set_cx8);
long long atomic64_xchg_cx8(long long, unsigned high);
EXPORT_SYMBOL(atomic64_xchg_cx8);
long long atomic64_add_return_cx8(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_add_return_cx8);
long long atomic64_sub_return_cx8(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_sub_return_cx8);
long long atomic64_inc_return_cx8(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_inc_return_cx8);
long long atomic64_dec_return_cx8(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_dec_return_cx8);
long long atomic64_dec_if_positive_cx8(atomic64_t *v);
EXPORT_SYMBOL(atomic64_dec_if_positive_cx8);
int atomic64_inc_not_zero_cx8(atomic64_t *v);
EXPORT_SYMBOL(atomic64_inc_not_zero_cx8);
int atomic64_add_unless_cx8(atomic64_t *v, long long a, long long u);
EXPORT_SYMBOL(atomic64_add_unless_cx8);
asm volatile(
LOCK_PREFIX "cmpxchg8b %1\n"
: "+A" (old), "+m" (*ptr)
: "b" (low), "c" (high)
);
return old;
}
u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val)
{
return cmpxchg8b(&ptr->counter, old_val, new_val);
}
EXPORT_SYMBOL(atomic64_cmpxchg);
/**
* atomic64_xchg - xchg atomic64 variable
* @ptr: pointer to type atomic64_t
* @new_val: value to assign
*
* Atomically xchgs the value of @ptr to @new_val and returns
* the old value.
*/
u64 atomic64_xchg(atomic64_t *ptr, u64 new_val)
{
/*
* Try first with a (possibly incorrect) assumption about
* what we have there. We'll do two loops most likely,
* but we'll get an ownership MESI transaction straight away
* instead of a read transaction followed by a
* flush-for-ownership transaction:
*/
u64 old_val, real_val = 0;
do {
old_val = real_val;
real_val = atomic64_cmpxchg(ptr, old_val, new_val);
} while (real_val != old_val);
return old_val;
}
EXPORT_SYMBOL(atomic64_xchg);
/**
* atomic64_set - set atomic64 variable
* @ptr: pointer to type atomic64_t
* @new_val: value to assign
*
* Atomically sets the value of @ptr to @new_val.
*/
void atomic64_set(atomic64_t *ptr, u64 new_val)
{
atomic64_xchg(ptr, new_val);
}
EXPORT_SYMBOL(atomic64_set);
/**
EXPORT_SYMBOL(atomic64_read);
* atomic64_add_return - add and return
* @delta: integer value to add
* @ptr: pointer to type atomic64_t
*
* Atomically adds @delta to @ptr and returns @delta + *@ptr
*/
noinline u64 atomic64_add_return(u64 delta, atomic64_t *ptr)
{
/*
* Try first with a (possibly incorrect) assumption about
* what we have there. We'll do two loops most likely,
* but we'll get an ownership MESI transaction straight away
* instead of a read transaction followed by a
* flush-for-ownership transaction:
*/
u64 old_val, new_val, real_val = 0;
do {
old_val = real_val;
new_val = old_val + delta;
real_val = atomic64_cmpxchg(ptr, old_val, new_val);
} while (real_val != old_val);
return new_val;
}
EXPORT_SYMBOL(atomic64_add_return);
u64 atomic64_sub_return(u64 delta, atomic64_t *ptr)
{
return atomic64_add_return(-delta, ptr);
}
EXPORT_SYMBOL(atomic64_sub_return);
u64 atomic64_inc_return(atomic64_t *ptr)
{
return atomic64_add_return(1, ptr);
}
EXPORT_SYMBOL(atomic64_inc_return);
u64 atomic64_dec_return(atomic64_t *ptr)
{
return atomic64_sub_return(1, ptr);
}
EXPORT_SYMBOL(atomic64_dec_return);
/**
* atomic64_add - add integer to atomic64 variable
* @delta: integer value to add
* @ptr: pointer to type atomic64_t
*
* Atomically adds @delta to @ptr.
*/
void atomic64_add(u64 delta, atomic64_t *ptr)
{
atomic64_add_return(delta, ptr);
}
EXPORT_SYMBOL(atomic64_add);
/**
* atomic64_sub - subtract the atomic64 variable
* @delta: integer value to subtract
* @ptr: pointer to type atomic64_t
*
* Atomically subtracts @delta from @ptr.
*/
void atomic64_sub(u64 delta, atomic64_t *ptr)
{
atomic64_add(-delta, ptr);
}
EXPORT_SYMBOL(atomic64_sub);
/**
* atomic64_sub_and_test - subtract value from variable and test result
* @delta: integer value to subtract
* @ptr: pointer to type atomic64_t
*
* Atomically subtracts @delta from @ptr and returns
* true if the result is zero, or false for all
* other cases.
*/
int atomic64_sub_and_test(u64 delta, atomic64_t *ptr)
{
u64 new_val = atomic64_sub_return(delta, ptr);
return new_val == 0;
}
EXPORT_SYMBOL(atomic64_sub_and_test);
/**
* atomic64_inc - increment atomic64 variable
* @ptr: pointer to type atomic64_t
*
* Atomically increments @ptr by 1.
*/
void atomic64_inc(atomic64_t *ptr)
{
atomic64_add(1, ptr);
}
EXPORT_SYMBOL(atomic64_inc);
/**
* atomic64_dec - decrement atomic64 variable
* @ptr: pointer to type atomic64_t
*
* Atomically decrements @ptr by 1.
*/
void atomic64_dec(atomic64_t *ptr)
{
atomic64_sub(1, ptr);
}
EXPORT_SYMBOL(atomic64_dec);
/**
* atomic64_dec_and_test - decrement and test
* @ptr: pointer to type atomic64_t
*
* Atomically decrements @ptr by 1 and
* returns true if the result is 0, or false for all other
* cases.
*/
int atomic64_dec_and_test(atomic64_t *ptr)
{
return atomic64_sub_and_test(1, ptr);
}
EXPORT_SYMBOL(atomic64_dec_and_test);
/**
* atomic64_inc_and_test - increment and test
* @ptr: pointer to type atomic64_t
*
* Atomically increments @ptr by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
int atomic64_inc_and_test(atomic64_t *ptr)
{
return atomic64_sub_and_test(-1, ptr);
}
EXPORT_SYMBOL(atomic64_inc_and_test);
/**
* atomic64_add_negative - add and test if negative
* @delta: integer value to add
* @ptr: pointer to type atomic64_t
*
* Atomically adds @delta to @ptr and returns true
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
int atomic64_add_negative(u64 delta, atomic64_t *ptr)
{
s64 new_val = atomic64_add_return(delta, ptr);
return new_val < 0;
}
EXPORT_SYMBOL(atomic64_add_negative);
#ifndef CONFIG_X86_CMPXCHG64
long long atomic64_read_386(long long, const atomic64_t *v);
EXPORT_SYMBOL(atomic64_read_386);
long long atomic64_set_386(long long, const atomic64_t *v);
EXPORT_SYMBOL(atomic64_set_386);
long long atomic64_xchg_386(long long, unsigned high);
EXPORT_SYMBOL(atomic64_xchg_386);
long long atomic64_add_return_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_add_return_386);
long long atomic64_sub_return_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_sub_return_386);
long long atomic64_inc_return_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_inc_return_386);
long long atomic64_dec_return_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_dec_return_386);
long long atomic64_add_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_add_386);
long long atomic64_sub_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_sub_386);
long long atomic64_inc_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_inc_386);
long long atomic64_dec_386(long long a, atomic64_t *v);
EXPORT_SYMBOL(atomic64_dec_386);
long long atomic64_dec_if_positive_386(atomic64_t *v);
EXPORT_SYMBOL(atomic64_dec_if_positive_386);
int atomic64_inc_not_zero_386(atomic64_t *v);
EXPORT_SYMBOL(atomic64_inc_not_zero_386);
int atomic64_add_unless_386(atomic64_t *v, long long a, long long u);
EXPORT_SYMBOL(atomic64_add_unless_386);
#endif

174
arch/x86/lib/atomic64_386_32.S Normal file
View File

@ -0,0 +1,174 @@
/*
* atomic64_t for 386/486
*
* Copyright © 2010 Luca Barbieri
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/linkage.h>
#include <asm/alternative-asm.h>
#include <asm/dwarf2.h>
/* if you want SMP support, implement these with real spinlocks */
.macro LOCK reg
pushfl
CFI_ADJUST_CFA_OFFSET 4
cli
.endm
.macro UNLOCK reg
popfl
CFI_ADJUST_CFA_OFFSET -4
.endm
.macro BEGIN func reg
$v = \reg
ENTRY(atomic64_\func\()_386)
CFI_STARTPROC
LOCK $v
.macro RETURN
UNLOCK $v
ret
.endm
.macro END_
CFI_ENDPROC
ENDPROC(atomic64_\func\()_386)
.purgem RETURN
.purgem END_
.purgem END
.endm
.macro END
RETURN
END_
.endm
.endm
BEGIN read %ecx
movl ($v), %eax
movl 4($v), %edx
END
BEGIN set %esi
movl %ebx, ($v)
movl %ecx, 4($v)
END
BEGIN xchg %esi
movl ($v), %eax
movl 4($v), %edx
movl %ebx, ($v)
movl %ecx, 4($v)
END
BEGIN add %ecx
addl %eax, ($v)
adcl %edx, 4($v)
END
BEGIN add_return %ecx
addl ($v), %eax
adcl 4($v), %edx
movl %eax, ($v)
movl %edx, 4($v)
END
BEGIN sub %ecx
subl %eax, ($v)
sbbl %edx, 4($v)
END
BEGIN sub_return %ecx
negl %edx
negl %eax
sbbl $0, %edx
addl ($v), %eax
adcl 4($v), %edx
movl %eax, ($v)
movl %edx, 4($v)
END
BEGIN inc %esi
addl $1, ($v)
adcl $0, 4($v)
END
BEGIN inc_return %esi
movl ($v), %eax
movl 4($v), %edx
addl $1, %eax
adcl $0, %edx
movl %eax, ($v)
movl %edx, 4($v)
END
BEGIN dec %esi
subl $1, ($v)
sbbl $0, 4($v)
END
BEGIN dec_return %esi
movl ($v), %eax
movl 4($v), %edx
subl $1, %eax
sbbl $0, %edx
movl %eax, ($v)
movl %edx, 4($v)
END
BEGIN add_unless %ecx
addl %eax, %esi
adcl %edx, %edi
addl ($v), %eax
adcl 4($v), %edx
cmpl %eax, %esi
je 3f
1:
movl %eax, ($v)
movl %edx, 4($v)
movl $1, %eax
2:
RETURN
3:
cmpl %edx, %edi
jne 1b
xorl %eax, %eax
jmp 2b
END_
BEGIN inc_not_zero %esi
movl ($v), %eax
movl 4($v), %edx
testl %eax, %eax
je 3f
1:
addl $1, %eax
adcl $0, %edx
movl %eax, ($v)
movl %edx, 4($v)
movl $1, %eax
2:
RETURN
3:
testl %edx, %edx
jne 1b
jmp 2b
END_
BEGIN dec_if_positive %esi
movl ($v), %eax
movl 4($v), %edx
subl $1, %eax
sbbl $0, %edx
js 1f
movl %eax, ($v)
movl %edx, 4($v)
1:
END

224
arch/x86/lib/atomic64_cx8_32.S Normal file
View File

@ -0,0 +1,224 @@
/*
* atomic64_t for 586+
*
* Copyright © 2010 Luca Barbieri
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/linkage.h>
#include <asm/alternative-asm.h>
#include <asm/dwarf2.h>
.macro SAVE reg
pushl %\reg
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET \reg, 0
.endm
.macro RESTORE reg
popl %\reg
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE \reg
.endm
.macro read64 reg
movl %ebx, %eax
movl %ecx, %edx
/* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */
LOCK_PREFIX
cmpxchg8b (\reg)
.endm
ENTRY(atomic64_read_cx8)
CFI_STARTPROC
read64 %ecx
ret
CFI_ENDPROC
ENDPROC(atomic64_read_cx8)
ENTRY(atomic64_set_cx8)
CFI_STARTPROC
1:
/* we don't need LOCK_PREFIX since aligned 64-bit writes
* are atomic on 586 and newer */
cmpxchg8b (%esi)
jne 1b
ret
CFI_ENDPROC
ENDPROC(atomic64_set_cx8)
ENTRY(atomic64_xchg_cx8)
CFI_STARTPROC
movl %ebx, %eax
movl %ecx, %edx
1:
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
ret
CFI_ENDPROC
ENDPROC(atomic64_xchg_cx8)
.macro addsub_return func ins insc
ENTRY(atomic64_\func\()_return_cx8)
CFI_STARTPROC
SAVE ebp
SAVE ebx
SAVE esi
SAVE edi
movl %eax, %esi
movl %edx, %edi
movl %ecx, %ebp
read64 %ebp
1:
movl %eax, %ebx
movl %edx, %ecx
\ins\()l %esi, %ebx
\insc\()l %edi, %ecx
LOCK_PREFIX
cmpxchg8b (%ebp)
jne 1b
10:
movl %ebx, %eax
movl %ecx, %edx
RESTORE edi
RESTORE esi
RESTORE ebx
RESTORE ebp
ret
CFI_ENDPROC
ENDPROC(atomic64_\func\()_return_cx8)
.endm
addsub_return add add adc
addsub_return sub sub sbb
.macro incdec_return func ins insc
ENTRY(atomic64_\func\()_return_cx8)
CFI_STARTPROC
SAVE ebx
read64 %esi
1:
movl %eax, %ebx
movl %edx, %ecx
\ins\()l $1, %ebx
\insc\()l $0, %ecx
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
10:
movl %ebx, %eax
movl %ecx, %edx
RESTORE ebx
ret
CFI_ENDPROC
ENDPROC(atomic64_\func\()_return_cx8)
.endm
incdec_return inc add adc
incdec_return dec sub sbb
ENTRY(atomic64_dec_if_positive_cx8)
CFI_STARTPROC
SAVE ebx
read64 %esi
1:
movl %eax, %ebx
movl %edx, %ecx
subl $1, %ebx
sbb $0, %ecx
js 2f
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
2:
movl %ebx, %eax
movl %ecx, %edx
RESTORE ebx
ret
CFI_ENDPROC
ENDPROC(atomic64_dec_if_positive_cx8)
ENTRY(atomic64_add_unless_cx8)
CFI_STARTPROC
SAVE ebp
SAVE ebx
/* these just push these two parameters on the stack */
SAVE edi
SAVE esi
movl %ecx, %ebp
movl %eax, %esi
movl %edx, %edi
read64 %ebp
1:
cmpl %eax, 0(%esp)
je 4f
2:
movl %eax, %ebx
movl %edx, %ecx
addl %esi, %ebx
adcl %edi, %ecx
LOCK_PREFIX
cmpxchg8b (%ebp)
jne 1b
movl $1, %eax
3:
addl $8, %esp
CFI_ADJUST_CFA_OFFSET -8
RESTORE ebx
RESTORE ebp
ret
4:
cmpl %edx, 4(%esp)
jne 2b
xorl %eax, %eax
jmp 3b
CFI_ENDPROC
ENDPROC(atomic64_add_unless_cx8)
ENTRY(atomic64_inc_not_zero_cx8)
CFI_STARTPROC
SAVE ebx
read64 %esi
1:
testl %eax, %eax
je 4f
2:
movl %eax, %ebx
movl %edx, %ecx
addl $1, %ebx
adcl $0, %ecx
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
movl $1, %eax
3:
RESTORE ebx
ret
4:
testl %edx, %edx
jne 2b
jmp 3b
CFI_ENDPROC
ENDPROC(atomic64_inc_not_zero_cx8)

7
lib/Kconfig.debug
View File

@ -1098,6 +1098,13 @@ config DMA_API_DEBUG
This option causes a performance degredation. Use only if you want
to debug device drivers. If unsure, say N.
config ATOMIC64_SELFTEST
bool "Perform an atomic64_t self-test at boot"
help
Enable this option to test the atomic64_t functions at boot.
If unsure, say N.
source "samples/Kconfig"
source "lib/Kconfig.kgdb"

2
lib/Makefile
View File

@ -101,6 +101,8 @@ obj-$(CONFIG_GENERIC_CSUM) += checksum.o
obj-$(CONFIG_GENERIC_ATOMIC64) += atomic64.o
obj-$(CONFIG_ATOMIC64_SELFTEST) += atomic64_test.o
hostprogs-y := gen_crc32table
clean-files := crc32table.h

4
lib/atomic64.c
View File

@ -162,12 +162,12 @@ int atomic64_add_unless(atomic64_t *v, long long a, long long u)
{
unsigned long flags;
spinlock_t *lock = lock_addr(v);
int ret = 1;
int ret = 0;
spin_lock_irqsave(lock, flags);
if (v->counter != u) {
v->counter += a;
ret = 0;
ret = 1;
}
spin_unlock_irqrestore(lock, flags);
return ret;

164
lib/atomic64_test.c Normal file
View File

@ -0,0 +1,164 @@
/*
* Testsuite for atomic64_t functions
*
* Copyright © 2010 Luca Barbieri
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/init.h>
#include <asm/atomic.h>
#define INIT(c) do { atomic64_set(&v, c); r = c; } while (0)
static __init int test_atomic64(void)
{
long long v0 = 0xaaa31337c001d00dLL;
long long v1 = 0xdeadbeefdeafcafeLL;
long long v2 = 0xfaceabadf00df001LL;
long long onestwos = 0x1111111122222222LL;
long long one = 1LL;
atomic64_t v = ATOMIC64_INIT(v0);
long long r = v0;
BUG_ON(v.counter != r);
atomic64_set(&v, v1);
r = v1;
BUG_ON(v.counter != r);
BUG_ON(atomic64_read(&v) != r);
INIT(v0);
atomic64_add(onestwos, &v);
r += onestwos;
BUG_ON(v.counter != r);
INIT(v0);
atomic64_add(-one, &v);
r += -one;
BUG_ON(v.counter != r);
INIT(v0);
r += onestwos;
BUG_ON(atomic64_add_return(onestwos, &v) != r);
BUG_ON(v.counter != r);
INIT(v0);
r += -one;
BUG_ON(atomic64_add_return(-one, &v) != r);
BUG_ON(v.counter != r);
INIT(v0);
atomic64_sub(onestwos, &v);
r -= onestwos;
BUG_ON(v.counter != r);
INIT(v0);
atomic64_sub(-one, &v);
r -= -one;
BUG_ON(v.counter != r);
INIT(v0);
r -= onestwos;
BUG_ON(atomic64_sub_return(onestwos, &v) != r);
BUG_ON(v.counter != r);
INIT(v0);
r -= -one;
BUG_ON(atomic64_sub_return(-one, &v) != r);
BUG_ON(v.counter != r);
INIT(v0);
atomic64_inc(&v);
r += one;
BUG_ON(v.counter != r);
INIT(v0);
r += one;
BUG_ON(atomic64_inc_return(&v) != r);
BUG_ON(v.counter != r);
INIT(v0);
atomic64_dec(&v);
r -= one;
BUG_ON(v.counter != r);
INIT(v0);
r -= one;
BUG_ON(atomic64_dec_return(&v) != r);
BUG_ON(v.counter != r);
INIT(v0);
BUG_ON(atomic64_xchg(&v, v1) != v0);
r = v1;
BUG_ON(v.counter != r);
INIT(v0);
BUG_ON(atomic64_cmpxchg(&v, v0, v1) != v0);
r = v1;
BUG_ON(v.counter != r);
INIT(v0);
BUG_ON(atomic64_cmpxchg(&v, v2, v1) != v0);
BUG_ON(v.counter != r);
INIT(v0);
BUG_ON(atomic64_add_unless(&v, one, v0));
BUG_ON(v.counter != r);
INIT(v0);
BUG_ON(!atomic64_add_unless(&v, one, v1));
r += one;
BUG_ON(v.counter != r);
#if defined(CONFIG_X86) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || defined(_ASM_GENERIC_ATOMIC64_H)
INIT(onestwos);
BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
r -= one;
BUG_ON(v.counter != r);
INIT(0);
BUG_ON(atomic64_dec_if_positive(&v) != -one);
BUG_ON(v.counter != r);
INIT(-one);
BUG_ON(atomic64_dec_if_positive(&v) != (-one - one));
BUG_ON(v.counter != r);
#else
#warning Please implement atomic64_dec_if_positive for your architecture, and add it to the IF above
#endif
INIT(onestwos);
BUG_ON(!atomic64_inc_not_zero(&v));
r += one;
BUG_ON(v.counter != r);
INIT(0);
BUG_ON(atomic64_inc_not_zero(&v));
BUG_ON(v.counter != r);
INIT(-one);
BUG_ON(!atomic64_inc_not_zero(&v));
r += one;
BUG_ON(v.counter != r);
#ifdef CONFIG_X86
printk(KERN_INFO "atomic64 test passed for %s platform %s CX8 and %s SSE\n",
#ifdef CONFIG_X86_64
"x86-64",
#elif defined(CONFIG_X86_CMPXCHG64)
"i586+",
#else
"i386+",
#endif
boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
#else
printk(KERN_INFO "atomic64 test passed\n");
#endif
return 0;
}
core_initcall(test_atomic64);