diff options
Diffstat (limited to 'libc/arch-arm')
| -rw-r--r-- | libc/arch-arm/bionic/atomics_arm.S | 10 | ||||
| -rw-r--r-- | libc/arch-arm/include/machine/cpu-features.h | 7 |
2 files changed, 17 insertions, 0 deletions
diff --git a/libc/arch-arm/bionic/atomics_arm.S b/libc/arch-arm/bionic/atomics_arm.S index b2da09f..57c4239 100644 --- a/libc/arch-arm/bionic/atomics_arm.S +++ b/libc/arch-arm/bionic/atomics_arm.S @@ -129,8 +129,18 @@ __atomic_inc: #endif /* r0(new) r1(addr) -> r0(old) */ +/* replaced swp instruction with ldrex/strex for ARMv6 & ARMv7 */ __atomic_swap: +#if defined (_ARM_HAVE_LDREX_STREX) +1: ldrex r2, [r1] + strex r3, r0, [r1] + teq r3, #0 + bne 1b + mov r0, r2 + mcr p15, 0, r0, c7, c10, 5 /* or, use dmb */ +#else swp r0, r0, [r1] +#endif bx lr /* __futex_wait(*ftx, val, *timespec) */ diff --git a/libc/arch-arm/include/machine/cpu-features.h b/libc/arch-arm/include/machine/cpu-features.h index f836006..ecf6ff6 100644 --- a/libc/arch-arm/include/machine/cpu-features.h +++ b/libc/arch-arm/include/machine/cpu-features.h @@ -149,6 +149,13 @@ # define __ARM_HAVE_PC_INTERWORK #endif +/* define _ARM_HAVE_LDREX_STREX for ARMv6 and ARMv7 architecure to be + * used in replacement of depricated swp instruction + */ +#if __ARM_ARCH__ >= 6 +# define _ARM_HAVE_LDREX_STREX +#endif + /* Assembly-only macros */ |