/* * Copyright (C) 2005 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include /* * NOTE: these atomic operations are SMP safe on all architectures, * except swap(), see below. */ .text .align .global android_atomic_write .global android_atomic_inc .global android_atomic_dec .global android_atomic_add .global android_atomic_and .global android_atomic_or .global android_atomic_swap .global android_atomic_cmpxchg /* * ---------------------------------------------------------------------------- * int __kernel_cmpxchg(int oldval, int newval, int *ptr) * clobbered: r3, ip, flags * return 0 if a swap was made, non-zero otherwise. */ .equ kernel_cmpxchg, 0xFFFF0FC0 .equ kernel_atomic_base, 0xFFFF0FFF /* * ---------------------------------------------------------------------------- * android_atomic_write * input: r0=value, r1=address * output: void */ android_atomic_write: stmdb sp!, {r4, lr} mov r2, r1 mov r1, r0 1: @ android_atomic_write ldr r0, [r2] mov r3, #kernel_atomic_base #ifdef __ARM_HAVE_PC_INTERWORK add lr, pc, #4 add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) #else add r3, r3, #(kernel_cmpxchg - kernel_atomic_base) mov lr, pc bx r3 #endif bcc 1b ldmia sp!, {r4, lr} bx lr /* * ---------------------------------------------------------------------------- * android_atomic_inc * input: r0 = address * output: r0 = old value */ android_atomic_inc: stmdb sp!, {r4, lr} mov r2, r0 1: @ android_atomic_inc ldr r0, [r2] mov r3, #kernel_atomic_base #ifdef __ARM_HAVE_PC_INTERWORK add lr, pc, #4 add r1, r0, #1 add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) #else add r1, r0, #1 add r3, r3, #(kernel_cmpxchg - kernel_atomic_base) mov lr, pc bx r3 #endif bcc 1b sub r0, r1, #1 ldmia sp!, {r4, lr} bx lr /* * ---------------------------------------------------------------------------- * android_atomic_dec * input: r0=address * output: r0 = old value */ android_atomic_dec: stmdb sp!, {r4, lr} mov r2, r0 1: @ android_atomic_dec ldr r0, [r2] mov r3, #kernel_atomic_base #ifdef __ARM_HAVE_PC_INTERWORK add lr, pc, #4 sub r1, r0, #1 add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) #else sub r1, r0, #1 add r3, r3, #(kernel_cmpxchg - kernel_atomic_base) mov lr, pc bx r3 #endif bcc 1b add r0, r1, #1 ldmia sp!, {r4, lr} bx lr /* * ---------------------------------------------------------------------------- * android_atomic_add * input: r0=value, r1=address * output: r0 = old value */ android_atomic_add: stmdb sp!, {r4, lr} mov r2, r1 mov r4, r0 1: @ android_atomic_add ldr r0, [r2] mov r3, #kernel_atomic_base #ifdef __ARM_HAVE_PC_INTERWORK add lr, pc, #4 add r1, r0, r4 add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) #else add r1, r0, r4 add r3, r3, #(kernel_cmpxchg - kernel_atomic_base) mov lr, pc bx r3 #endif bcc 1b sub r0, r1, r4 ldmia sp!, {r4, lr} bx lr /* * ---------------------------------------------------------------------------- * android_atomic_and * input: r0=value, r1=address * output: r0 = old value */ android_atomic_and: stmdb sp!, {r4, r5, lr} mov r2, r1 /* r2 = address */ mov r4, r0 /* r4 = the value */ 1: @ android_atomic_and ldr r0, [r2] /* r0 = address[0] */ mov r3, #kernel_atomic_base #ifdef __ARM_HAVE_PC_INTERWORK add lr, pc, #8 mov r5, r0 /* r5 = save address[0] */ and r1, r0, r4 /* r1 = new value */ add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) /* call cmpxchg() */ #else mov r5, r0 /* r5 = save address[0] */ and r1, r0, r4 /* r1 = new value */ add r3, r3, #(kernel_cmpxchg - kernel_atomic_base) /* call cmpxchg() */ mov lr, pc bx r3 #endif bcc 1b mov r0, r5 ldmia sp!, {r4, r5, lr} bx lr /* * ---------------------------------------------------------------------------- * android_atomic_or * input: r0=value, r1=address * output: r0 = old value */ android_atomic_or: stmdb sp!, {r4, r5, lr} mov r2, r1 /* r2 = address */ mov r4, r0 /* r4 = the value */ 1: @ android_atomic_or ldr r0, [r2] /* r0 = address[0] */ mov r3, #kernel_atomic_base #ifdef __ARM_HAVE_PC_INTERWORK add lr, pc, #8 mov r5, r0 /* r5 = save address[0] */ orr r1, r0, r4 /* r1 = new value */ add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) /* call cmpxchg() */ #else mov r5, r0 /* r5 = save address[0] */ orr r1, r0, r4 /* r1 = new value */ add r3, r3, #(kernel_cmpxchg - kernel_atomic_base) /* call cmpxchg() */ mov lr, pc bx r3 #endif bcc 1b mov r0, r5 ldmia sp!, {r4, r5, lr} bx lr /* * ---------------------------------------------------------------------------- * android_atomic_swap * input: r0=value, r1=address * output: r0 = old value */ /* FIXME: this is not safe on SMP systems * a general way to do it is to use kernel_cmpxchg */ android_atomic_swap: swp r0, r0, [r1] bx lr /* * ---------------------------------------------------------------------------- * android_atomic_cmpxchg * input: r0=oldvalue, r1=newvalue, r2=address * output: r0 = 0 (xchg done) or non-zero (xchg not done) */ android_atomic_cmpxchg: stmdb sp!, {r4, lr} mov r4, r0 /* r4 = save oldvalue */ 1: @ android_atomic_cmpxchg mov r3, #kernel_atomic_base #ifdef __ARM_HAVE_PC_INTERWORK add lr, pc, #4 mov r0, r4 /* r0 = oldvalue */ add pc, r3, #(kernel_cmpxchg - kernel_atomic_base) #else mov r0, r4 /* r0 = oldvalue */ add r3, r3, #(kernel_cmpxchg - kernel_atomic_base) mov lr, pc bx r3 #endif 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: @ android_atomic_cmpxchg ldmia sp!, {r4, lr} bx lr /* * ---------------------------------------------------------------------------- * android_atomic_cmpxchg_64 * input: r0-r1=oldvalue, r2-r3=newvalue, arg4 (on stack)=address * output: r0 = 0 (xchg done) or non-zero (xchg not done) */ /* TODO: NEED IMPLEMENTATION FOR THIS ARCHITECTURE */