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arm64: implement atomic-store with CAS
Only available with ARMv8.1 or higher, so behind a flag that would be enabled by an ACE compatible compiler depending on -march. As a sideeffect, avoids the races that could result in an infloop with M1.
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| @@ -0,0 +1,116 @@ | ||
| /* | ||
| * $CC [-DDEADLOCK] -Isljit_src -o deadlock deadlock.c sljit_src/sljitLir.c | ||
| * | ||
| * SPDX: 0BSD | ||
| * | ||
| * © 2023 Carlo Marcelo Arenas Belón | ||
| */ | ||
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| #include "sljitLir.h" | ||
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| #include <stdio.h> | ||
| #include <stdlib.h> | ||
| #include <pthread.h> | ||
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| struct data { | ||
| long value; | ||
| long *canary; | ||
| pthread_t id; | ||
| }; | ||
| typedef void *(*worker_fn)(void *); | ||
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| static int gdb; | ||
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| static worker_fn create_worker(void) | ||
| { | ||
| worker_fn code; | ||
| struct sljit_label *retry; | ||
| struct sljit_jump *exit, *skip; | ||
| struct sljit_compiler *C = sljit_create_compiler(NULL, NULL); | ||
| #if SLJIT_CONFIG_X86 | ||
| sljit_u8 inst = 0xcc; | ||
| #elif SLJIT_CONFIG_S390X | ||
| sljit_u8 inst[2] = { 0x0, 0x1 }; | ||
| #elif SLJIT_CONFIG_ARM_64 | ||
| sljit_u32 inst = 0xd4200000; | ||
| #elif SLJIT_CONFIG_ARM_THUMB2 | ||
| sljit_u16 inst = 0xde01; | ||
| #elif SLJIT_CONFIG_ARM | ||
| sljit_u32 inst = 0xe7d001f0; | ||
| #else | ||
| //#error "Not Supported" | ||
| #endif | ||
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| sljit_emit_enter(C, 0, SLJIT_ARGS1(P, P), 6, 1, 0, 0, 0); | ||
| if (gdb) | ||
| sljit_emit_op_custom(C, &inst, sizeof(inst)); | ||
| sljit_emit_op2(C, SLJIT_ADD, SLJIT_R5, 0, SLJIT_S0, 0, | ||
| SLJIT_IMM, SLJIT_OFFSETOF(struct data, canary)); | ||
| sljit_emit_op1(C, SLJIT_MOV, SLJIT_R1, 0, SLJIT_IMM, 0); | ||
| retry = sljit_emit_label(C); | ||
| sljit_emit_atomic_load(C, SLJIT_MOV, SLJIT_R2, SLJIT_S0); | ||
| // skip = sljit_emit_cmp(C, SLJIT_EQUAL, SLJIT_MEM1(SLJIT_R4), 0, | ||
| // SLJIT_IMM, 0); | ||
| sljit_emit_op1(C, SLJIT_MOV, SLJIT_R4, 0, SLJIT_MEM1(SLJIT_R5), 0); | ||
| #ifdef DEADLOCK | ||
| sljit_emit_op1(C, SLJIT_MOV, SLJIT_MEM1(SLJIT_R4), 0, SLJIT_IMM, 1000); | ||
| #else | ||
| sljit_emit_op1(C, SLJIT_MOV, SLJIT_R4, 0, SLJIT_MEM1(SLJIT_R4), 0); | ||
| #endif | ||
| // sljit_set_label(skip, sljit_emit_label(C)); | ||
| sljit_emit_op2(C, SLJIT_ADD, SLJIT_R1, 0, SLJIT_R1, 0, SLJIT_IMM, 1); | ||
| sljit_emit_atomic_store(C, SLJIT_MOV | SLJIT_SET_ATOMIC_STORED, | ||
| SLJIT_R1, SLJIT_S0, SLJIT_R2); | ||
| exit = sljit_emit_jump(C, SLJIT_ATOMIC_STORED); | ||
| sljit_set_label(sljit_emit_jump(C, SLJIT_JUMP), retry); | ||
| sljit_set_label(exit, sljit_emit_label(C)); | ||
| sljit_emit_op1(C, SLJIT_MOV, SLJIT_RETURN_REG, 0, SLJIT_IMM, 0); | ||
| sljit_emit_return(C, SLJIT_MOV_P, SLJIT_RETURN_REG, 0); | ||
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| code = sljit_generate_code(C); | ||
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| sljit_free_compiler(C); | ||
| return code; | ||
| } | ||
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| int main(int argc, char *argv[]) | ||
| { | ||
| int winner = 0, looser = 0, other = 0; | ||
| int i, num_threads = -1; | ||
| struct data *threads; | ||
| worker_fn code; | ||
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| if (argc > 1) | ||
| num_threads = atoi(argv[1]); | ||
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| if (argc > 2) | ||
| gdb = 1; | ||
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| code = create_worker(); | ||
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| if (num_threads <= 0) | ||
| num_threads = 1; | ||
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| threads = calloc(num_threads, sizeof(struct data)); | ||
| for (i = 0; i < num_threads; i++) { | ||
| threads[i].canary = i ? &threads[i - 1].value : | ||
| &threads[num_threads - 1].value; | ||
| pthread_create(&threads[i].id, NULL, code, &threads[i].value); | ||
| } | ||
| for (i = 0; i < num_threads; i++) | ||
| pthread_join(threads[i].id, NULL); | ||
| for (i = 0; i < num_threads; i++) { | ||
| switch(threads[i].value) { | ||
| case 1: ++winner; break; | ||
| case 1000: ++looser; break; | ||
| default: ++other; printf("%ld\n", threads[i].value); | ||
| } | ||
| } | ||
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| printf("threads: %d won, %d lost, %d hang\n", winner, looser, other); | ||
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| free(threads); | ||
| sljit_free_code((void *)code, NULL); | ||
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| return 0; | ||
| } |
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