1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Verify that a single TB spin-loop is properly invalidated, 4 * releasing the thread from the spin-loop. 5 */ 6 7 #include <assert.h> 8 #include <sys/mman.h> 9 #include <pthread.h> 10 #include <stdint.h> 11 #include <stdbool.h> 12 #include <unistd.h> 13 #include <sched.h> 14 15 16 #ifdef __x86_64__ 17 #define READY 0x000047c6 /* movb $0,0(%rdi) */ 18 #define LOOP 0xfceb9090 /* 1: nop*2; jmp 1b */ 19 #define RETURN 0x909090c3 /* ret; nop*3 */ 20 #define NOP 0x90909090 /* nop*4 */ 21 #elif defined(__aarch64__) 22 #define READY 0x3900001f /* strb wzr,[x0] */ 23 #define LOOP 0x14000000 /* b . */ 24 #define RETURN 0xd65f03c0 /* ret */ 25 #define NOP 0xd503201f /* nop */ 26 #elif defined(__riscv) 27 #define READY 0x00050023 /* sb zero, (a0) */ 28 #define LOOP 0x0000006f /* jal zero, #0 */ 29 #define RETURN 0x00008067 /* jalr zero, ra, 0 */ 30 #define NOP 0x00000013 /* nop */ 31 #endif 32 33 34 int main() 35 { 36 #ifdef READY 37 int tmp; 38 pthread_t thread_id; 39 bool hold = true; 40 uint32_t *buf; 41 42 buf = mmap(NULL, 3 * sizeof(uint32_t), 43 PROT_READ | PROT_WRITE | PROT_EXEC, 44 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 45 assert(buf != MAP_FAILED); 46 47 buf[0] = READY; 48 buf[1] = LOOP; 49 buf[2] = RETURN; 50 51 alarm(2); 52 53 tmp = pthread_create(&thread_id, NULL, (void *(*)(void *))buf, &hold); 54 assert(tmp == 0); 55 56 while (hold) { 57 sched_yield(); 58 } 59 60 buf[1] = NOP; 61 __builtin___clear_cache(&buf[1], &buf[2]); 62 63 tmp = pthread_join(thread_id, NULL); 64 assert(tmp == 0); 65 #endif 66 return 0; 67 } 68