167 lines
4.9 KiB
C
167 lines
4.9 KiB
C
/* 64bit Linux-specific atomic operations for ARM EABI.
|
|
Copyright (C) 2008-2018 Free Software Foundation, Inc.
|
|
Based on linux-atomic.c
|
|
|
|
64 bit additions david.gilbert@linaro.org
|
|
|
|
This file is part of GCC.
|
|
|
|
GCC 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 3, or (at your option) any later
|
|
version.
|
|
|
|
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
|
|
WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
for more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* 64bit helper functions for atomic operations; the compiler will
|
|
call these when the code is compiled for a CPU without ldrexd/strexd.
|
|
(If the CPU had those then the compiler inlines the operation).
|
|
|
|
These helpers require a kernel helper that's only present on newer
|
|
kernels; we check for that in an init section and bail out rather
|
|
unceremoneously. */
|
|
|
|
extern int write (int fd, const void *buf, unsigned int count);
|
|
extern void abort (void);
|
|
|
|
/* Kernel helper for compare-and-exchange. */
|
|
typedef int (__kernel_cmpxchg64_t) (const long long* oldval,
|
|
const long long* newval,
|
|
long long *ptr);
|
|
#define __kernel_cmpxchg64 (*(__kernel_cmpxchg64_t *) 0xffff0f60)
|
|
|
|
/* Kernel helper page version number. */
|
|
#define __kernel_helper_version (*(unsigned int *)0xffff0ffc)
|
|
|
|
/* Check that the kernel has a new enough version at load. */
|
|
static void __check_for_sync8_kernelhelper (void)
|
|
{
|
|
if (__kernel_helper_version < 5)
|
|
{
|
|
const char err[] = "A newer kernel is required to run this binary. "
|
|
"(__kernel_cmpxchg64 helper)\n";
|
|
/* At this point we need a way to crash with some information
|
|
for the user - I'm not sure I can rely on much else being
|
|
available at this point, so do the same as generic-morestack.c
|
|
write () and abort (). */
|
|
write (2 /* stderr. */, err, sizeof (err));
|
|
abort ();
|
|
}
|
|
};
|
|
|
|
static void (*__sync8_kernelhelper_inithook[]) (void)
|
|
__attribute__ ((used, section (".init_array"))) = {
|
|
&__check_for_sync8_kernelhelper
|
|
};
|
|
|
|
#define HIDDEN __attribute__ ((visibility ("hidden")))
|
|
|
|
#define FETCH_AND_OP_WORD64(OP, PFX_OP, INF_OP) \
|
|
long long HIDDEN \
|
|
__sync_fetch_and_##OP##_8 (long long *ptr, long long val) \
|
|
{ \
|
|
int failure; \
|
|
long long tmp,tmp2; \
|
|
\
|
|
do { \
|
|
tmp = *ptr; \
|
|
tmp2 = PFX_OP (tmp INF_OP val); \
|
|
failure = __kernel_cmpxchg64 (&tmp, &tmp2, ptr); \
|
|
} while (failure != 0); \
|
|
\
|
|
return tmp; \
|
|
}
|
|
|
|
FETCH_AND_OP_WORD64 (add, , +)
|
|
FETCH_AND_OP_WORD64 (sub, , -)
|
|
FETCH_AND_OP_WORD64 (or, , |)
|
|
FETCH_AND_OP_WORD64 (and, , &)
|
|
FETCH_AND_OP_WORD64 (xor, , ^)
|
|
FETCH_AND_OP_WORD64 (nand, ~, &)
|
|
|
|
#define NAME_oldval(OP, WIDTH) __sync_fetch_and_##OP##_##WIDTH
|
|
#define NAME_newval(OP, WIDTH) __sync_##OP##_and_fetch_##WIDTH
|
|
|
|
/* Implement both __sync_<op>_and_fetch and __sync_fetch_and_<op> for
|
|
subword-sized quantities. */
|
|
|
|
#define OP_AND_FETCH_WORD64(OP, PFX_OP, INF_OP) \
|
|
long long HIDDEN \
|
|
__sync_##OP##_and_fetch_8 (long long *ptr, long long val) \
|
|
{ \
|
|
int failure; \
|
|
long long tmp,tmp2; \
|
|
\
|
|
do { \
|
|
tmp = *ptr; \
|
|
tmp2 = PFX_OP (tmp INF_OP val); \
|
|
failure = __kernel_cmpxchg64 (&tmp, &tmp2, ptr); \
|
|
} while (failure != 0); \
|
|
\
|
|
return tmp2; \
|
|
}
|
|
|
|
OP_AND_FETCH_WORD64 (add, , +)
|
|
OP_AND_FETCH_WORD64 (sub, , -)
|
|
OP_AND_FETCH_WORD64 (or, , |)
|
|
OP_AND_FETCH_WORD64 (and, , &)
|
|
OP_AND_FETCH_WORD64 (xor, , ^)
|
|
OP_AND_FETCH_WORD64 (nand, ~, &)
|
|
|
|
long long HIDDEN
|
|
__sync_val_compare_and_swap_8 (long long *ptr, long long oldval,
|
|
long long newval)
|
|
{
|
|
int failure;
|
|
long long actual_oldval;
|
|
|
|
while (1)
|
|
{
|
|
actual_oldval = *ptr;
|
|
|
|
if (__builtin_expect (oldval != actual_oldval, 0))
|
|
return actual_oldval;
|
|
|
|
failure = __kernel_cmpxchg64 (&actual_oldval, &newval, ptr);
|
|
|
|
if (__builtin_expect (!failure, 1))
|
|
return oldval;
|
|
}
|
|
}
|
|
|
|
typedef unsigned char bool;
|
|
|
|
bool HIDDEN
|
|
__sync_bool_compare_and_swap_8 (long long *ptr, long long oldval,
|
|
long long newval)
|
|
{
|
|
int failure = __kernel_cmpxchg64 (&oldval, &newval, ptr);
|
|
return (failure == 0);
|
|
}
|
|
|
|
long long HIDDEN
|
|
__sync_lock_test_and_set_8 (long long *ptr, long long val)
|
|
{
|
|
int failure;
|
|
long long oldval;
|
|
|
|
do {
|
|
oldval = *ptr;
|
|
failure = __kernel_cmpxchg64 (&oldval, &val, ptr);
|
|
} while (failure != 0);
|
|
|
|
return oldval;
|
|
}
|