diff options
Diffstat (limited to 'arch/x86/lib/atomic64_32.c')
| -rw-r--r-- | arch/x86/lib/atomic64_32.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c new file mode 100644 index 00000000000..824fa0be55a --- /dev/null +++ b/arch/x86/lib/atomic64_32.c @@ -0,0 +1,230 @@ +#include <linux/compiler.h> +#include <linux/module.h> +#include <linux/types.h> + +#include <asm/processor.h> +#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; + + 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); |