diff options
Diffstat (limited to 'libgcc/config/arm/linux-atomic-64bit.c')
| -rw-r--r-- | libgcc/config/arm/linux-atomic-64bit.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/libgcc/config/arm/linux-atomic-64bit.c b/libgcc/config/arm/linux-atomic-64bit.c new file mode 100644 index 0000000..af94c7f --- /dev/null +++ b/libgcc/config/arm/linux-atomic-64bit.c @@ -0,0 +1,166 @@ +/* 64bit Linux-specific atomic operations for ARM EABI. + Copyright (C) 2008, 2009, 2010, 2011 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 unsigned 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; +} |