diff options
Diffstat (limited to 'libc/sysdeps/linux/arm/bits/atomic.h')
| -rw-r--r-- | libc/sysdeps/linux/arm/bits/atomic.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/arm/bits/atomic.h b/libc/sysdeps/linux/arm/bits/atomic.h new file mode 100644 index 000000000..0b90330dd --- /dev/null +++ b/libc/sysdeps/linux/arm/bits/atomic.h @@ -0,0 +1,136 @@ +/* Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#if defined __thumb__ && !defined __thumb2__ +#include_next <common/bits/atomic.h> +#else +#include <stdint.h> +#include <sysdep.h> + + +typedef int8_t atomic8_t; +typedef uint8_t uatomic8_t; +typedef int_fast8_t atomic_fast8_t; +typedef uint_fast8_t uatomic_fast8_t; + +typedef int32_t atomic32_t; +typedef uint32_t uatomic32_t; +typedef int_fast32_t atomic_fast32_t; +typedef uint_fast32_t uatomic_fast32_t; + +typedef intptr_t atomicptr_t; +typedef uintptr_t uatomicptr_t; +typedef intmax_t atomic_max_t; +typedef uintmax_t uatomic_max_t; + +void __arm_link_error (void); + +/* Use the atomic builtins provided by GCC in case the backend provides + a pattern to do this efficiently. */ + +#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 +#define atomic_full_barrier() __sync_synchronize () +#elif defined __thumb2__ +#define atomic_full_barrier() \ + __asm__ __volatile__ \ + ("movw\tip, #0x0fa0\n\t" \ + "movt\tip, #0xffff\n\t" \ + "blx\tip" \ + : : : "ip", "lr", "cc", "memory"); +#else +#define atomic_full_barrier() \ + __asm__ __volatile__ \ + ("mov\tip, #0xffff0fff\n\t" \ + "mov\tlr, pc\n\t" \ + "add\tpc, ip, #(0xffff0fa0 - 0xffff0fff)" \ + : : : "ip", "lr", "cc", "memory"); +#endif + +/* Atomic compare and exchange. This sequence relies on the kernel to + provide a compare and exchange operation which is atomic on the + current architecture, either via cleverness on pre-ARMv6 or via + ldrex / strex on ARMv6. */ + +#define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \ + ({ __arm_link_error (); oldval; }) + +#define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \ + ({ __arm_link_error (); oldval; }) + +#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 +#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \ + __sync_val_compare_and_swap ((mem), (oldval), (newval)) + +/* It doesn't matter what register is used for a_oldval2, but we must + specify one to work around GCC PR rtl-optimization/21223. Otherwise + it may cause a_oldval or a_tmp to be moved to a different register. */ + +#elif defined __thumb2__ +/* Thumb-2 has ldrex/strex. However it does not have barrier instructions, + so we still need to use the kernel helper. */ +#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \ + ({ register __typeof (oldval) a_oldval __asm__ ("r0"); \ + register __typeof (oldval) a_newval __asm__ ("r1") = (newval); \ + register __typeof (mem) a_ptr __asm__ ("r2") = (mem); \ + register __typeof (oldval) a_tmp __asm__ ("r3"); \ + register __typeof (oldval) a_oldval2 __asm__ ("r4") = (oldval); \ + __asm__ __volatile__ \ + ("0:\tldr\t%[tmp],[%[ptr]]\n\t" \ + "cmp\t%[tmp], %[old2]\n\t" \ + "bne\t1f\n\t" \ + "mov\t%[old], %[old2]\n\t" \ + "movw\t%[tmp], #0x0fc0\n\t" \ + "movt\t%[tmp], #0xffff\n\t" \ + "blx\t%[tmp]\n\t" \ + "bcc\t0b\n\t" \ + "mov\t%[tmp], %[old2]\n\t" \ + "1:" \ + : [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp) \ + : [new] "r" (a_newval), [ptr] "r" (a_ptr), \ + [old2] "r" (a_oldval2) \ + : "ip", "lr", "cc", "memory"); \ + a_tmp; }) +#else +#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \ + ({ register __typeof (oldval) a_oldval __asm__ ("r0"); \ + register __typeof (oldval) a_newval __asm__ ("r1") = (newval); \ + register __typeof (mem) a_ptr __asm__ ("r2") = (mem); \ + register __typeof (oldval) a_tmp __asm__ ("r3"); \ + register __typeof (oldval) a_oldval2 __asm__ ("r4") = (oldval); \ + __asm__ __volatile__ \ + ("0:\tldr\t%[tmp],[%[ptr]]\n\t" \ + "cmp\t%[tmp], %[old2]\n\t" \ + "bne\t1f\n\t" \ + "mov\t%[old], %[old2]\n\t" \ + "mov\t%[tmp], #0xffff0fff\n\t" \ + "mov\tlr, pc\n\t" \ + "add\tpc, %[tmp], #(0xffff0fc0 - 0xffff0fff)\n\t" \ + "bcc\t0b\n\t" \ + "mov\t%[tmp], %[old2]\n\t" \ + "1:" \ + : [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp) \ + : [new] "r" (a_newval), [ptr] "r" (a_ptr), \ + [old2] "r" (a_oldval2) \ + : "ip", "lr", "cc", "memory"); \ + a_tmp; }) +#endif + +#define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \ + ({ __arm_link_error (); oldval; }) + +#endif |