f-stack/freebsd/arm/arm/stdatomic.c

430 lines
14 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2013 Ed Schouten <ed@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/stdatomic.h>
#include <sys/types.h>
#include <machine/atomic.h>
#include <machine/cpufunc.h>
#include <machine/sysarch.h>
/*
* Executing statements with interrupts disabled.
*/
#if defined(_KERNEL) && !defined(SMP)
#define WITHOUT_INTERRUPTS(s) do { \
register_t regs; \
\
regs = intr_disable(); \
do s while (0); \
intr_restore(regs); \
} while (0)
#endif /* _KERNEL && !SMP */
/*
* Memory barriers.
*
* It turns out __sync_synchronize() does not emit any code when used
* with GCC 4.2. Implement our own version that does work reliably.
*
* Although __sync_lock_test_and_set() should only perform an acquire
* barrier, make it do a full barrier like the other functions. This
* should make <stdatomic.h>'s atomic_exchange_explicit() work reliably.
*/
#if defined(_KERNEL) && !defined(SMP)
static inline void
do_sync(void)
{
__asm volatile ("" : : : "memory");
}
#else
static inline void
do_sync(void)
{
dmb();
}
#endif
#if defined(__SYNC_ATOMICS) || defined(EMIT_SYNC_ATOMICS)
#ifdef __clang__
#pragma redefine_extname __sync_lock_test_and_set_1_c __sync_lock_test_and_set_1
#pragma redefine_extname __sync_lock_test_and_set_2_c __sync_lock_test_and_set_2
#pragma redefine_extname __sync_lock_test_and_set_4_c __sync_lock_test_and_set_4
#pragma redefine_extname __sync_val_compare_and_swap_1_c __sync_val_compare_and_swap_1
#pragma redefine_extname __sync_val_compare_and_swap_2_c __sync_val_compare_and_swap_2
#pragma redefine_extname __sync_val_compare_and_swap_4_c __sync_val_compare_and_swap_4
#pragma redefine_extname __sync_fetch_and_add_1_c __sync_fetch_and_add_1
#pragma redefine_extname __sync_fetch_and_add_2_c __sync_fetch_and_add_2
#pragma redefine_extname __sync_fetch_and_add_4_c __sync_fetch_and_add_4
#pragma redefine_extname __sync_fetch_and_and_1_c __sync_fetch_and_and_1
#pragma redefine_extname __sync_fetch_and_and_2_c __sync_fetch_and_and_2
#pragma redefine_extname __sync_fetch_and_and_4_c __sync_fetch_and_and_4
#pragma redefine_extname __sync_fetch_and_or_1_c __sync_fetch_and_or_1
#pragma redefine_extname __sync_fetch_and_or_2_c __sync_fetch_and_or_2
#pragma redefine_extname __sync_fetch_and_or_4_c __sync_fetch_and_or_4
#pragma redefine_extname __sync_fetch_and_xor_1_c __sync_fetch_and_xor_1
#pragma redefine_extname __sync_fetch_and_xor_2_c __sync_fetch_and_xor_2
#pragma redefine_extname __sync_fetch_and_xor_4_c __sync_fetch_and_xor_4
#pragma redefine_extname __sync_fetch_and_sub_1_c __sync_fetch_and_sub_1
#pragma redefine_extname __sync_fetch_and_sub_2_c __sync_fetch_and_sub_2
#pragma redefine_extname __sync_fetch_and_sub_4_c __sync_fetch_and_sub_4
#endif
/*
* Old __sync_* API.
*/
/* Implementations for old GCC versions, lacking support for atomics. */
typedef union {
uint8_t v8[4];
uint32_t v32;
} reg_t;
/*
* Given a memory address pointing to an 8-bit or 16-bit integer, return
* the address of the 32-bit word containing it.
*/
static inline uint32_t *
round_to_word(void *ptr)
{
return ((uint32_t *)((intptr_t)ptr & ~3));
}
/*
* Utility functions for loading and storing 8-bit and 16-bit integers
* in 32-bit words at an offset corresponding with the location of the
* atomic variable.
*/
static inline void
put_1(reg_t *r, const uint8_t *offset_ptr, uint8_t val)
{
size_t offset;
offset = (intptr_t)offset_ptr & 3;
r->v8[offset] = val;
}
static inline uint8_t
get_1(const reg_t *r, const uint8_t *offset_ptr)
{
size_t offset;
offset = (intptr_t)offset_ptr & 3;
return (r->v8[offset]);
}
static inline void
put_2(reg_t *r, const uint16_t *offset_ptr, uint16_t val)
{
size_t offset;
union {
uint16_t in;
uint8_t out[2];
} bytes;
offset = (intptr_t)offset_ptr & 3;
bytes.in = val;
r->v8[offset] = bytes.out[0];
r->v8[offset + 1] = bytes.out[1];
}
static inline uint16_t
get_2(const reg_t *r, const uint16_t *offset_ptr)
{
size_t offset;
union {
uint8_t in[2];
uint16_t out;
} bytes;
offset = (intptr_t)offset_ptr & 3;
bytes.in[0] = r->v8[offset];
bytes.in[1] = r->v8[offset + 1];
return (bytes.out);
}
/*
* 8-bit and 16-bit routines.
*
* These operations are not natively supported by the CPU, so we use
* some shifting and bitmasking on top of the 32-bit instructions.
*/
#define EMIT_LOCK_TEST_AND_SET_N(N, uintN_t) \
uintN_t \
__sync_lock_test_and_set_##N##_c(uintN_t *mem, uintN_t val) \
{ \
uint32_t *mem32; \
reg_t val32, negmask, old; \
uint32_t temp1, temp2; \
\
mem32 = round_to_word(mem); \
val32.v32 = 0x00000000; \
put_##N(&val32, mem, val); \
negmask.v32 = 0xffffffff; \
put_##N(&negmask, mem, 0); \
\
do_sync(); \
__asm volatile ( \
"1:" \
"\tldrex %0, %6\n" /* Load old value. */ \
"\tand %2, %5, %0\n" /* Remove the old value. */ \
"\torr %2, %2, %4\n" /* Put in the new value. */ \
"\tstrex %3, %2, %1\n" /* Attempt to store. */ \
"\tcmp %3, #0\n" /* Did it succeed? */ \
"\tbne 1b\n" /* Spin if failed. */ \
: "=&r" (old.v32), "=m" (*mem32), "=&r" (temp1), \
"=&r" (temp2) \
: "r" (val32.v32), "r" (negmask.v32), "m" (*mem32)); \
return (get_##N(&old, mem)); \
}
EMIT_LOCK_TEST_AND_SET_N(1, uint8_t)
EMIT_LOCK_TEST_AND_SET_N(2, uint16_t)
#define EMIT_VAL_COMPARE_AND_SWAP_N(N, uintN_t) \
uintN_t \
__sync_val_compare_and_swap_##N##_c(uintN_t *mem, uintN_t expected, \
uintN_t desired) \
{ \
uint32_t *mem32; \
reg_t expected32, desired32, posmask, old; \
uint32_t negmask, temp1, temp2; \
\
mem32 = round_to_word(mem); \
expected32.v32 = 0x00000000; \
put_##N(&expected32, mem, expected); \
desired32.v32 = 0x00000000; \
put_##N(&desired32, mem, desired); \
posmask.v32 = 0x00000000; \
put_##N(&posmask, mem, ~0); \
negmask = ~posmask.v32; \
\
do_sync(); \
__asm volatile ( \
"1:" \
"\tldrex %0, %8\n" /* Load old value. */ \
"\tand %2, %6, %0\n" /* Isolate the old value. */ \
"\tcmp %2, %4\n" /* Compare to expected value. */\
"\tbne 2f\n" /* Values are unequal. */ \
"\tand %2, %7, %0\n" /* Remove the old value. */ \
"\torr %2, %5\n" /* Put in the new value. */ \
"\tstrex %3, %2, %1\n" /* Attempt to store. */ \
"\tcmp %3, #0\n" /* Did it succeed? */ \
"\tbne 1b\n" /* Spin if failed. */ \
"2:" \
: "=&r" (old), "=m" (*mem32), "=&r" (temp1), \
"=&r" (temp2) \
: "r" (expected32.v32), "r" (desired32.v32), \
"r" (posmask.v32), "r" (negmask), "m" (*mem32)); \
return (get_##N(&old, mem)); \
}
EMIT_VAL_COMPARE_AND_SWAP_N(1, uint8_t)
EMIT_VAL_COMPARE_AND_SWAP_N(2, uint16_t)
#define EMIT_ARITHMETIC_FETCH_AND_OP_N(N, uintN_t, name, op) \
uintN_t \
__sync_##name##_##N##_c(uintN_t *mem, uintN_t val) \
{ \
uint32_t *mem32; \
reg_t val32, posmask, old; \
uint32_t negmask, temp1, temp2; \
\
mem32 = round_to_word(mem); \
val32.v32 = 0x00000000; \
put_##N(&val32, mem, val); \
posmask.v32 = 0x00000000; \
put_##N(&posmask, mem, ~0); \
negmask = ~posmask.v32; \
\
do_sync(); \
__asm volatile ( \
"1:" \
"\tldrex %0, %7\n" /* Load old value. */ \
"\t"op" %2, %0, %4\n" /* Calculate new value. */ \
"\tand %2, %5\n" /* Isolate the new value. */ \
"\tand %3, %6, %0\n" /* Remove the old value. */ \
"\torr %2, %2, %3\n" /* Put in the new value. */ \
"\tstrex %3, %2, %1\n" /* Attempt to store. */ \
"\tcmp %3, #0\n" /* Did it succeed? */ \
"\tbne 1b\n" /* Spin if failed. */ \
: "=&r" (old.v32), "=m" (*mem32), "=&r" (temp1), \
"=&r" (temp2) \
: "r" (val32.v32), "r" (posmask.v32), "r" (negmask), \
"m" (*mem32)); \
return (get_##N(&old, mem)); \
}
EMIT_ARITHMETIC_FETCH_AND_OP_N(1, uint8_t, fetch_and_add, "add")
EMIT_ARITHMETIC_FETCH_AND_OP_N(1, uint8_t, fetch_and_sub, "sub")
EMIT_ARITHMETIC_FETCH_AND_OP_N(2, uint16_t, fetch_and_add, "add")
EMIT_ARITHMETIC_FETCH_AND_OP_N(2, uint16_t, fetch_and_sub, "sub")
#define EMIT_BITWISE_FETCH_AND_OP_N(N, uintN_t, name, op, idempotence) \
uintN_t \
__sync_##name##_##N##_c(uintN_t *mem, uintN_t val) \
{ \
uint32_t *mem32; \
reg_t val32, old; \
uint32_t temp1, temp2; \
\
mem32 = round_to_word(mem); \
val32.v32 = idempotence ? 0xffffffff : 0x00000000; \
put_##N(&val32, mem, val); \
\
do_sync(); \
__asm volatile ( \
"1:" \
"\tldrex %0, %5\n" /* Load old value. */ \
"\t"op" %2, %4, %0\n" /* Calculate new value. */ \
"\tstrex %3, %2, %1\n" /* Attempt to store. */ \
"\tcmp %3, #0\n" /* Did it succeed? */ \
"\tbne 1b\n" /* Spin if failed. */ \
: "=&r" (old.v32), "=m" (*mem32), "=&r" (temp1), \
"=&r" (temp2) \
: "r" (val32.v32), "m" (*mem32)); \
return (get_##N(&old, mem)); \
}
EMIT_BITWISE_FETCH_AND_OP_N(1, uint8_t, fetch_and_and, "and", 1)
EMIT_BITWISE_FETCH_AND_OP_N(1, uint8_t, fetch_and_or, "orr", 0)
EMIT_BITWISE_FETCH_AND_OP_N(1, uint8_t, fetch_and_xor, "eor", 0)
EMIT_BITWISE_FETCH_AND_OP_N(2, uint16_t, fetch_and_and, "and", 1)
EMIT_BITWISE_FETCH_AND_OP_N(2, uint16_t, fetch_and_or, "orr", 0)
EMIT_BITWISE_FETCH_AND_OP_N(2, uint16_t, fetch_and_xor, "eor", 0)
/*
* 32-bit routines.
*/
uint32_t
__sync_lock_test_and_set_4_c(uint32_t *mem, uint32_t val)
{
uint32_t old, temp;
do_sync();
__asm volatile (
"1:"
"\tldrex %0, %4\n" /* Load old value. */
"\tstrex %2, %3, %1\n" /* Attempt to store. */
"\tcmp %2, #0\n" /* Did it succeed? */
"\tbne 1b\n" /* Spin if failed. */
: "=&r" (old), "=m" (*mem), "=&r" (temp)
: "r" (val), "m" (*mem));
return (old);
}
uint32_t
__sync_val_compare_and_swap_4_c(uint32_t *mem, uint32_t expected,
uint32_t desired)
{
uint32_t old, temp;
do_sync();
__asm volatile (
"1:"
"\tldrex %0, %5\n" /* Load old value. */
"\tcmp %0, %3\n" /* Compare to expected value. */
"\tbne 2f\n" /* Values are unequal. */
"\tstrex %2, %4, %1\n" /* Attempt to store. */
"\tcmp %2, #0\n" /* Did it succeed? */
"\tbne 1b\n" /* Spin if failed. */
"2:"
: "=&r" (old), "=m" (*mem), "=&r" (temp)
: "r" (expected), "r" (desired), "m" (*mem));
return (old);
}
#define EMIT_FETCH_AND_OP_4(name, op) \
uint32_t \
__sync_##name##_4##_c(uint32_t *mem, uint32_t val) \
{ \
uint32_t old, temp1, temp2; \
\
do_sync(); \
__asm volatile ( \
"1:" \
"\tldrex %0, %5\n" /* Load old value. */ \
"\t"op" %2, %0, %4\n" /* Calculate new value. */ \
"\tstrex %3, %2, %1\n" /* Attempt to store. */ \
"\tcmp %3, #0\n" /* Did it succeed? */ \
"\tbne 1b\n" /* Spin if failed. */ \
: "=&r" (old), "=m" (*mem), "=&r" (temp1), \
"=&r" (temp2) \
: "r" (val), "m" (*mem)); \
return (old); \
}
EMIT_FETCH_AND_OP_4(fetch_and_add, "add")
EMIT_FETCH_AND_OP_4(fetch_and_and, "and")
EMIT_FETCH_AND_OP_4(fetch_and_or, "orr")
EMIT_FETCH_AND_OP_4(fetch_and_sub, "sub")
EMIT_FETCH_AND_OP_4(fetch_and_xor, "eor")
#ifndef __clang__
__strong_reference(__sync_lock_test_and_set_1_c, __sync_lock_test_and_set_1);
__strong_reference(__sync_lock_test_and_set_2_c, __sync_lock_test_and_set_2);
__strong_reference(__sync_lock_test_and_set_4_c, __sync_lock_test_and_set_4);
__strong_reference(__sync_val_compare_and_swap_1_c, __sync_val_compare_and_swap_1);
__strong_reference(__sync_val_compare_and_swap_2_c, __sync_val_compare_and_swap_2);
__strong_reference(__sync_val_compare_and_swap_4_c, __sync_val_compare_and_swap_4);
__strong_reference(__sync_fetch_and_add_1_c, __sync_fetch_and_add_1);
__strong_reference(__sync_fetch_and_add_2_c, __sync_fetch_and_add_2);
__strong_reference(__sync_fetch_and_add_4_c, __sync_fetch_and_add_4);
__strong_reference(__sync_fetch_and_and_1_c, __sync_fetch_and_and_1);
__strong_reference(__sync_fetch_and_and_2_c, __sync_fetch_and_and_2);
__strong_reference(__sync_fetch_and_and_4_c, __sync_fetch_and_and_4);
__strong_reference(__sync_fetch_and_sub_1_c, __sync_fetch_and_sub_1);
__strong_reference(__sync_fetch_and_sub_2_c, __sync_fetch_and_sub_2);
__strong_reference(__sync_fetch_and_sub_4_c, __sync_fetch_and_sub_4);
__strong_reference(__sync_fetch_and_or_1_c, __sync_fetch_and_or_1);
__strong_reference(__sync_fetch_and_or_2_c, __sync_fetch_and_or_2);
__strong_reference(__sync_fetch_and_or_4_c, __sync_fetch_and_or_4);
__strong_reference(__sync_fetch_and_xor_1_c, __sync_fetch_and_xor_1);
__strong_reference(__sync_fetch_and_xor_2_c, __sync_fetch_and_xor_2);
__strong_reference(__sync_fetch_and_xor_4_c, __sync_fetch_and_xor_4);
#endif
#endif /* __SYNC_ATOMICS */