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x86: atomic64: Move the 32-bit atomic64_t implementation to a .c file
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Linus noted that the atomic64_t primitives are all inlines
currently which is crazy because these functions have a large
register footprint anyway.

Move them to a separate file: arch/x86/lib/atomic64_32.c

Also, while at it, rename all uses of 'unsigned long long' to
the much shorter u64.

This makes the appearance of the prototypes a lot nicer - and
it also uncovered a few bugs where (yet unused) API variants
had 'long' as their return type instead of u64.

[ More intrusive changes are not yet done in this patch. ]

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Ingo Molnar committed Jul 3, 2009
1 parent bbf2a33 commit b7882b7
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Showing 3 changed files with 237 additions and 117 deletions.
137 changes: 20 additions & 117 deletions arch/x86/include/asm/atomic_32.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -250,7 +250,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
/* An 64bit atomic type */

typedef struct {
unsigned long long __aligned(8) counter;
u64 __aligned(8) counter;
} atomic64_t;

#define ATOMIC64_INIT(val) { (val) }
Expand All @@ -264,31 +264,7 @@ typedef struct {
*/
#define __atomic64_read(ptr) ((ptr)->counter)

static inline unsigned long long
cmpxchg8b(unsigned long long *ptr, unsigned long long old, unsigned long long new)
{
asm volatile(

LOCK_PREFIX "cmpxchg8b (%[ptr])\n"

: "=A" (old)

: [ptr] "D" (ptr),
"A" (old),
"b" (ll_low(new)),
"c" (ll_high(new))

: "memory");

return old;
}

static inline unsigned long long
atomic64_cmpxchg(atomic64_t *ptr, unsigned long long old_val,
unsigned long long new_val)
{
return cmpxchg8b(&ptr->counter, old_val, new_val);
}
extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);

/**
* atomic64_xchg - xchg atomic64 variable
Expand All @@ -298,18 +274,7 @@ atomic64_cmpxchg(atomic64_t *ptr, unsigned long long old_val,
* Atomically xchgs the value of @ptr to @new_val and returns
* the old value.
*/

static inline unsigned long long
atomic64_xchg(atomic64_t *ptr, unsigned long long new_val)
{
unsigned long long old_val;

do {
old_val = atomic_read(ptr);
} while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val);

return old_val;
}
extern u64 atomic64_xchg(atomic64_t *ptr, u64 new_val);

/**
* atomic64_set - set atomic64 variable
Expand All @@ -318,27 +283,15 @@ atomic64_xchg(atomic64_t *ptr, unsigned long long new_val)
*
* Atomically sets the value of @ptr to @new_val.
*/
static inline void atomic64_set(atomic64_t *ptr, unsigned long long new_val)
{
atomic64_xchg(ptr, new_val);
}
extern void atomic64_set(atomic64_t *ptr, u64 new_val);

/**
* atomic64_read - read atomic64 variable
* @ptr: pointer to type atomic64_t
*
* Atomically reads the value of @ptr and returns it.
*/
static inline unsigned long long atomic64_read(atomic64_t *ptr)
{
unsigned long long curr_val;

do {
curr_val = __atomic64_read(ptr);
} while (atomic64_cmpxchg(ptr, curr_val, curr_val) != curr_val);

return curr_val;
}
extern u64 atomic64_read(atomic64_t *ptr);

/**
* atomic64_add_return - add and return
Expand All @@ -347,34 +300,14 @@ static inline unsigned long long atomic64_read(atomic64_t *ptr)
*
* Atomically adds @delta to @ptr and returns @delta + *@ptr
*/
static inline unsigned long long
atomic64_add_return(unsigned long long delta, atomic64_t *ptr)
{
unsigned long long old_val, new_val;

do {
old_val = atomic_read(ptr);
new_val = old_val + delta;

} while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val);

return new_val;
}

static inline long atomic64_sub_return(unsigned long long delta, atomic64_t *ptr)
{
return atomic64_add_return(-delta, ptr);
}
extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);

static inline long atomic64_inc_return(atomic64_t *ptr)
{
return atomic64_add_return(1, ptr);
}

static inline long atomic64_dec_return(atomic64_t *ptr)
{
return atomic64_sub_return(1, ptr);
}
/*
* 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);

/**
* atomic64_add - add integer to atomic64 variable
Expand All @@ -383,10 +316,7 @@ static inline long atomic64_dec_return(atomic64_t *ptr)
*
* Atomically adds @delta to @ptr.
*/
static inline void atomic64_add(unsigned long long delta, atomic64_t *ptr)
{
atomic64_add_return(delta, ptr);
}
extern void atomic64_add(u64 delta, atomic64_t *ptr);

/**
* atomic64_sub - subtract the atomic64 variable
Expand All @@ -395,10 +325,7 @@ static inline void atomic64_add(unsigned long long delta, atomic64_t *ptr)
*
* Atomically subtracts @delta from @ptr.
*/
static inline void atomic64_sub(unsigned long long delta, atomic64_t *ptr)
{
atomic64_add(-delta, ptr);
}
extern void atomic64_sub(u64 delta, atomic64_t *ptr);

/**
* atomic64_sub_and_test - subtract value from variable and test result
Expand All @@ -409,35 +336,23 @@ static inline void atomic64_sub(unsigned long long delta, atomic64_t *ptr)
* true if the result is zero, or false for all
* other cases.
*/
static inline int
atomic64_sub_and_test(unsigned long long delta, atomic64_t *ptr)
{
unsigned long long old_val = atomic64_sub_return(delta, ptr);

return old_val == 0;
}
extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);

/**
* atomic64_inc - increment atomic64 variable
* @ptr: pointer to type atomic64_t
*
* Atomically increments @ptr by 1.
*/
static inline void atomic64_inc(atomic64_t *ptr)
{
atomic64_add(1, ptr);
}
extern void atomic64_inc(atomic64_t *ptr);

/**
* atomic64_dec - decrement atomic64 variable
* @ptr: pointer to type atomic64_t
*
* Atomically decrements @ptr by 1.
*/
static inline void atomic64_dec(atomic64_t *ptr)
{
atomic64_sub(1, ptr);
}
extern void atomic64_dec(atomic64_t *ptr);

/**
* atomic64_dec_and_test - decrement and test
Expand All @@ -447,10 +362,7 @@ static inline void atomic64_dec(atomic64_t *ptr)
* returns true if the result is 0, or false for all other
* cases.
*/
static inline int atomic64_dec_and_test(atomic64_t *ptr)
{
return atomic64_sub_and_test(1, ptr);
}
extern int atomic64_dec_and_test(atomic64_t *ptr);

/**
* atomic64_inc_and_test - increment and test
Expand All @@ -460,10 +372,7 @@ static inline int atomic64_dec_and_test(atomic64_t *ptr)
* and returns true if the result is zero, or false for all
* other cases.
*/
static inline int atomic64_inc_and_test(atomic64_t *ptr)
{
return atomic64_sub_and_test(-1, ptr);
}
extern int atomic64_inc_and_test(atomic64_t *ptr);

/**
* atomic64_add_negative - add and test if negative
Expand All @@ -474,13 +383,7 @@ static inline int atomic64_inc_and_test(atomic64_t *ptr)
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
static inline int
atomic64_add_negative(unsigned long long delta, atomic64_t *ptr)
{
long long old_val = atomic64_add_return(delta, ptr);

return old_val < 0;
}
extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);

#include <asm-generic/atomic-long.h>
#endif /* _ASM_X86_ATOMIC_32_H */
1 change: 1 addition & 0 deletions arch/x86/lib/Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ lib-y += usercopy_$(BITS).o getuser.o putuser.o
lib-y += memcpy_$(BITS).o

ifeq ($(CONFIG_X86_32),y)
lib-y += atomic64_32.o
lib-y += checksum_32.o
lib-y += strstr_32.o
lib-y += semaphore_32.o string_32.o
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