diff options
Diffstat (limited to 'libc/arch-arm/bionic/atomics_arm.S')
| -rw-r--r-- | libc/arch-arm/bionic/atomics_arm.S | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/libc/arch-arm/bionic/atomics_arm.S b/libc/arch-arm/bionic/atomics_arm.S new file mode 100644 index 0000000..b2da09f --- /dev/null +++ b/libc/arch-arm/bionic/atomics_arm.S @@ -0,0 +1,178 @@ +/* + * Copyright (C) 2008 The Android Open Source Project + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * 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 COPYRIGHT HOLDERS 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 + * COPYRIGHT OWNER 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/linux-syscalls.h> + +.global __atomic_cmpxchg +.global __atomic_swap +.global __atomic_dec +.global __atomic_inc +.global __futex_wait +.global __futex_wake + +#define FUTEX_WAIT 0 +#define FUTEX_WAKE 1 + +#if 1 + .equ kernel_cmpxchg, 0xFFFF0FC0 + .equ kernel_atomic_base, 0xFFFF0FFF +__atomic_dec: + stmdb sp!, {r4, lr} + mov r2, r0 +1: @ atomic_dec + ldr r0, [r2] + mov r3, #kernel_atomic_base + add lr, pc, #4 + sub r1, r0, #1 + add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) + bcc 1b + add r0, r1, #1 + ldmia sp!, {r4, lr} + bx lr + +__atomic_inc: + stmdb sp!, {r4, lr} + mov r2, r0 +1: @ atomic_inc + ldr r0, [r2] + mov r3, #kernel_atomic_base + add lr, pc, #4 + add r1, r0, #1 + add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) + bcc 1b + sub r0, r1, #1 + ldmia sp!, {r4, lr} + bx lr + +/* r0(old) r1(new) r2(addr) -> r0(zero_if_succeeded) */ +__atomic_cmpxchg: + stmdb sp!, {r4, lr} + mov r4, r0 /* r4 = save oldvalue */ +1: @ atomic_cmpxchg + mov r3, #kernel_atomic_base + add lr, pc, #4 + mov r0, r4 /* r0 = oldvalue */ + add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) + bcs 2f /* swap was made. we're good, return. */ + ldr r3, [r2] /* swap not made, see if it's because *ptr!=oldvalue */ + cmp r3, r4 + beq 1b +2: @ atomic_cmpxchg + ldmia sp!, {r4, lr} + bx lr +#else +#define KUSER_CMPXCHG 0xffffffc0 + +/* r0(old) r1(new) r2(addr) -> r0(zero_if_succeeded) */ +__atomic_cmpxchg: + stmdb sp!, {r4, lr} + mov r4, r0 /* r4 = save oldvalue */ +1: add lr, pc, #4 + mov r0, r4 /* r0 = oldvalue */ + mov pc, #KUSER_CMPXCHG + bcs 2f /* swap was made. we're good, return. */ + ldr r3, [r2] /* swap not made, see if it's because *ptr!=oldvalue */ + cmp r3, r4 + beq 1b +2: ldmia sp!, {r4, lr} + bx lr + +/* r0(addr) -> r0(old) */ +__atomic_dec: + stmdb sp!, {r4, lr} + mov r2, r0 /* address */ +1: ldr r0, [r2] /* oldvalue */ + add lr, pc, #4 + sub r1, r0, #1 /* newvalue = oldvalue - 1 */ + mov pc, #KUSER_CMPXCHG + bcc 1b /* no swap, try again until we get it right */ + mov r0, ip /* swapped, return the old value */ + ldmia sp!, {r4, lr} + bx lr + +/* r0(addr) -> r0(old) */ +__atomic_inc: + stmdb sp!, {r4, lr} + mov r2, r0 /* address */ +1: ldr r0, [r2] /* oldvalue */ + add lr, pc, #4 + add r1, r0, #1 /* newvalue = oldvalue + 1 */ + mov pc, #KUSER_CMPXCHG + bcc 1b /* no swap, try again until we get it right */ + mov r0, ip /* swapped, return the old value */ + ldmia sp!, {r4, lr} + bx lr +#endif + +/* r0(new) r1(addr) -> r0(old) */ +__atomic_swap: + swp r0, r0, [r1] + bx lr + +/* __futex_wait(*ftx, val, *timespec) */ +/* __futex_syscall(*ftx, op, val, *timespec, *addr2, val3) */ + +#if __ARM_EABI__ + +__futex_wait: + .fnstart + stmdb sp!, {r4, r7} + .save {r4, r7} + mov r3, r2 + mov r2, r1 + mov r1, #FUTEX_WAIT + ldr r7, =__NR_futex + swi #0 + ldmia sp!, {r4, r7} + bx lr + .fnend + +__futex_wake: + stmdb sp!, {r4, r7} + mov r2, r1 + mov r1, #FUTEX_WAKE + ldr r7, =__NR_futex + swi #0 + ldmia sp!, {r4, r7} + bx lr + +#else + +__futex_wait: + mov r3, r2 + mov r2, r1 + mov r1, #FUTEX_WAIT + swi #__NR_futex + bx lr + +__futex_wake: + mov r2, r1 + mov r1, #FUTEX_WAKE + swi #__NR_futex + bx lr + +#endif |