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/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
* applicable.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "apr.h"
#include "apr_atomic.h"
#include "apr_thread_mutex.h"
#include "apr_private.h"
#include <stdlib.h>
#if defined(__GNUC__) && defined(__STRICT_ANSI__) && !defined(USE_GENERIC_ATOMICS)
/* force use of generic atomics if building e.g. with -std=c89, which
* doesn't allow inline asm */
#define USE_GENERIC_ATOMICS
#endif
#if (defined(__i386__) || defined(__x86_64__)) \
&& defined(__GNUC__) && !defined(USE_GENERIC_ATOMICS)
APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem,
apr_uint32_t with,
apr_uint32_t cmp)
{
apr_uint32_t prev;
asm volatile ("lock; cmpxchgl %1, %2"
: "=a" (prev)
: "r" (with), "m" (*(mem)), "0"(cmp)
: "memory", "cc");
return prev;
}
#define APR_OVERRIDE_ATOMIC_CAS32
static apr_uint32_t inline intel_atomic_add32(volatile apr_uint32_t *mem,
apr_uint32_t val)
{
asm volatile ("lock; xaddl %0,%1"
: "=r"(val), "=m"(*mem) /* outputs */
: "0"(val), "m"(*mem) /* inputs */
: "memory", "cc");
return val;
}
APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem,
apr_uint32_t val)
{
return intel_atomic_add32(mem, val);
}
#define APR_OVERRIDE_ATOMIC_ADD32
APR_DECLARE(void) apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
asm volatile ("lock; subl %1, %0"
:
: "m" (*(mem)), "r" (val)
: "memory", "cc");
}
#define APR_OVERRIDE_ATOMIC_SUB32
APR_DECLARE(int) apr_atomic_dec32(volatile apr_uint32_t *mem)
{
unsigned char prev;
asm volatile ("lock; decl %1;\n\t"
"setnz %%al"
: "=a" (prev)
: "m" (*(mem))
: "memory", "cc");
return prev;
}
#define APR_OVERRIDE_ATOMIC_DEC32
APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem)
{
return intel_atomic_add32(mem, 1);
}
#define APR_OVERRIDE_ATOMIC_INC32
APR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
*mem = val;
}
#define APR_OVERRIDE_ATOMIC_SET32
APR_DECLARE(apr_uint32_t) apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
apr_uint32_t prev = val;
asm volatile ("lock; xchgl %0, %1"
: "=r" (prev)
: "m" (*(mem)), "0"(prev)
: "memory");
return prev;
}
#define APR_OVERRIDE_ATOMIC_XCHG32
/*#define apr_atomic_init(pool) APR_SUCCESS*/
#endif /* (__linux__ || __EMX__ || __FreeBSD__) && __i386__ */
#if (defined(__PPC__) || defined(__ppc__)) && defined(__GNUC__) \
&& !defined(USE_GENERIC_ATOMICS)
APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem,
apr_uint32_t swap,
apr_uint32_t cmp)
{
apr_uint32_t prev;
asm volatile ("0:\n\t" /* retry local label */
"lwarx %0,0,%1\n\t" /* load prev and reserve */
"cmpw %0,%3\n\t" /* does it match cmp? */
"bne- 1f\n\t" /* ...no, bail out */
"stwcx. %2,0,%1\n\t" /* ...yes, conditionally
store swap */
"bne- 0b\n\t" /* start over if we lost
the reservation */
"1:" /* exit local label */
: "=&r"(prev) /* output */
: "b" (mem), "r" (swap), "r"(cmp) /* inputs */
: "memory", "cc"); /* clobbered */
return prev;
}
#define APR_OVERRIDE_ATOMIC_CAS32
APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem,
apr_uint32_t delta)
{
apr_uint32_t prev, temp;
asm volatile ("0:\n\t" /* retry local label */
"lwarx %0,0,%2\n\t" /* load prev and reserve */
"add %1,%0,%3\n\t" /* temp = prev + delta */
"stwcx. %1,0,%2\n\t" /* conditionally store */
"bne- 0b" /* start over if we lost
the reservation */
/*XXX find a cleaner way to define the temp
* it's not an output
*/
: "=&r" (prev), "=&r" (temp) /* output, temp */
: "b" (mem), "r" (delta) /* inputs */
: "memory", "cc"); /* clobbered */
return prev;
}
#define APR_OVERRIDE_ATOMIC_ADD32
#endif /* __PPC__ && __GNUC__ */
#if !defined(APR_OVERRIDE_ATOMIC_INIT)
#if APR_HAS_THREADS
#define NUM_ATOMIC_HASH 7
/* shift by 2 to get rid of alignment issues */
#define ATOMIC_HASH(x) (unsigned int)(((unsigned long)(x)>>2)%(unsigned int)NUM_ATOMIC_HASH)
static apr_thread_mutex_t **hash_mutex;
#endif /* APR_HAS_THREADS */
apr_status_t apr_atomic_init(apr_pool_t *p)
{
#if APR_HAS_THREADS
int i;
apr_status_t rv;
hash_mutex = apr_palloc(p, sizeof(apr_thread_mutex_t*) * NUM_ATOMIC_HASH);
for (i = 0; i < NUM_ATOMIC_HASH; i++) {
rv = apr_thread_mutex_create(&(hash_mutex[i]),
APR_THREAD_MUTEX_DEFAULT, p);
if (rv != APR_SUCCESS) {
return rv;
}
}
#endif /* APR_HAS_THREADS */
return APR_SUCCESS;
}
#endif /* !defined(APR_OVERRIDE_ATOMIC_INIT) */
/* abort() if 'x' does not evaluate to APR_SUCCESS. */
#define CHECK(x) do { if ((x) != APR_SUCCESS) abort(); } while (0)
#if !defined(APR_OVERRIDE_ATOMIC_ADD32)
#if defined(APR_OVERRIDE_ATOMIC_CAS32)
apr_uint32_t apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
apr_uint32_t old_value, new_value;
do {
old_value = *mem;
new_value = old_value + val;
} while (apr_atomic_cas32(mem, new_value, old_value) != old_value);
return old_value;
}
#else
apr_uint32_t apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
apr_uint32_t old_value;
#if APR_HAS_THREADS
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
CHECK(apr_thread_mutex_lock(lock));
old_value = *mem;
*mem += val;
CHECK(apr_thread_mutex_unlock(lock));
#else
old_value = *mem;
*mem += val;
#endif /* APR_HAS_THREADS */
return old_value;
}
#endif /* defined(APR_OVERRIDE_ATOMIC_CAS32) */
#endif /* !defined(APR_OVERRIDE_ATOMIC_ADD32) */
#if !defined(APR_OVERRIDE_ATOMIC_SUB32)
#if defined(APR_OVERRIDE_ATOMIC_CAS32)
void apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
apr_uint32_t old_value, new_value;
do {
old_value = *mem;
new_value = old_value - val;
} while (apr_atomic_cas32(mem, new_value, old_value) != old_value);
}
#else
void apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
#if APR_HAS_THREADS
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
CHECK(apr_thread_mutex_lock(lock));
*mem -= val;
CHECK(apr_thread_mutex_unlock(lock));
#else
*mem -= val;
#endif /* APR_HAS_THREADS */
}
#endif /* defined(APR_OVERRIDE_ATOMIC_CAS32) */
#endif /* !defined(APR_OVERRIDE_ATOMIC_SUB32) */
#if !defined(APR_OVERRIDE_ATOMIC_SET32)
void apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
#if APR_HAS_THREADS
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
CHECK(apr_thread_mutex_lock(lock));
*mem = val;
CHECK(apr_thread_mutex_unlock(lock));
#else
*mem = val;
#endif /* APR_HAS_THREADS */
}
#endif /* !defined(APR_OVERRIDE_ATOMIC_SET32) */
#if !defined(APR_OVERRIDE_ATOMIC_INC32)
apr_uint32_t apr_atomic_inc32(volatile apr_uint32_t *mem)
{
return apr_atomic_add32(mem, 1);
}
#endif /* !defined(APR_OVERRIDE_ATOMIC_INC32) */
#if !defined(APR_OVERRIDE_ATOMIC_DEC32)
#if defined(APR_OVERRIDE_ATOMIC_CAS32)
int apr_atomic_dec32(volatile apr_uint32_t *mem)
{
apr_uint32_t old_value, new_value;
do {
old_value = *mem;
new_value = old_value - 1;
} while (apr_atomic_cas32(mem, new_value, old_value) != old_value);
return old_value != 1;
}
#else
int apr_atomic_dec32(volatile apr_uint32_t *mem)
{
#if APR_HAS_THREADS
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
apr_uint32_t new;
CHECK(apr_thread_mutex_lock(lock));
(*mem)--;
new = *mem;
CHECK(apr_thread_mutex_unlock(lock));
return new;
#else
(*mem)--;
return *mem;
#endif /* APR_HAS_THREADS */
}
#endif /* defined(APR_OVERRIDE_ATOMIC_CAS32) */
#endif /* !defined(APR_OVERRIDE_ATOMIC_DEC32) */
#if !defined(APR_OVERRIDE_ATOMIC_CAS32)
apr_uint32_t apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t with,
apr_uint32_t cmp)
{
apr_uint32_t prev;
#if APR_HAS_THREADS
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
CHECK(apr_thread_mutex_lock(lock));
prev = *mem;
if (prev == cmp) {
*mem = with;
}
CHECK(apr_thread_mutex_unlock(lock));
#else
prev = *mem;
if (prev == cmp) {
*mem = with;
}
#endif /* APR_HAS_THREADS */
return prev;
}
#endif /* !defined(APR_OVERRIDE_ATOMIC_CAS32) */
#if !defined(APR_OVERRIDE_ATOMIC_XCHG32)
#if defined(APR_OVERRIDE_ATOMIC_CAS32)
apr_uint32_t apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
apr_uint32_t prev;
do {
prev = *mem;
} while (apr_atomic_cas32(mem, val, prev) != prev);
return prev;
}
#else
apr_uint32_t apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val)
{
apr_uint32_t prev;
#if APR_HAS_THREADS
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
CHECK(apr_thread_mutex_lock(lock));
prev = *mem;
*mem = val;
CHECK(apr_thread_mutex_unlock(lock));
#else
prev = *mem;
*mem = val;
#endif /* APR_HAS_THREADS */
return prev;
}
#endif /* defined(APR_OVERRIDE_ATOMIC_CAS32) */
#endif /* !defined(APR_OVERRIDE_ATOMIC_XCHG32) */
#if !defined(APR_OVERRIDE_ATOMIC_CASPTR)
void *apr_atomic_casptr(volatile void **mem, void *with, const void *cmp)
{
void *prev;
#if APR_HAS_THREADS
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
CHECK(apr_thread_mutex_lock(lock));
prev = *(void **)mem;
if (prev == cmp) {
*mem = with;
}
CHECK(apr_thread_mutex_unlock(lock));
#else
prev = *(void **)mem;
if (prev == cmp) {
*mem = with;
}
#endif /* APR_HAS_THREADS */
return prev;
}
#endif /* !defined(APR_OVERRIDE_ATOMIC_CASPTR) */
#if !defined(APR_OVERRIDE_ATOMIC_READ32)
APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem)
{
return *mem;
}
#endif
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