| 1 | #define _GNU_SOURCE 1 |
| 2 | |
| 3 | #include <assert.h> |
| 4 | #include <stdlib.h> |
| 5 | #include <signal.h> |
| 6 | #include <endian.h> |
| 7 | |
| 8 | |
| 9 | char x[32] __attribute__((aligned(16))) = { |
| 10 | 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, |
| 11 | 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, |
| 12 | 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, |
| 13 | 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, |
| 14 | }; |
| 15 | void * volatile p = (void *)&x + 15; |
| 16 | |
| 17 | void sigbus(int sig, siginfo_t *info, void *uc) |
| 18 | { |
| 19 | assert(sig == SIGBUS); |
| 20 | assert(info->si_signo == SIGBUS); |
| 21 | #ifdef BUS_ADRALN |
| 22 | assert(info->si_code == BUS_ADRALN); |
| 23 | #endif |
| 24 | assert(info->si_addr == p); |
| 25 | exit(EXIT_SUCCESS); |
| 26 | } |
| 27 | |
| 28 | int main() |
| 29 | { |
| 30 | struct sigaction sa = { |
| 31 | .sa_sigaction = sigbus, |
| 32 | .sa_flags = SA_SIGINFO |
| 33 | }; |
| 34 | int allow_fail = 0; |
| 35 | int tmp; |
| 36 | |
| 37 | tmp = sigaction(SIGBUS, &sa, NULL); |
| 38 | assert(tmp == 0); |
| 39 | |
| 40 | /* |
| 41 | * Select an operation that's likely to enforce alignment. |
| 42 | * On many guests that support unaligned accesses by default, |
| 43 | * this is often an atomic operation. |
| 44 | */ |
| 45 | #if defined(__aarch64__) |
| 46 | asm volatile("ldxr %w0,[%1]" : "=r"(tmp) : "r"(p) : "memory"); |
| 47 | #elif defined(__alpha__) |
| 48 | asm volatile("ldl_l %0,0(%1)" : "=r"(tmp) : "r"(p) : "memory"); |
| 49 | #elif defined(__arm__) |
| 50 | asm volatile("ldrex %0,[%1]" : "=r"(tmp) : "r"(p) : "memory"); |
| 51 | #elif defined(__powerpc__) |
| 52 | asm volatile("lwarx %0,0,%1" : "=r"(tmp) : "r"(p) : "memory"); |
| 53 | #elif defined(__riscv_atomic) |
| 54 | asm volatile("lr.w %0,(%1)" : "=r"(tmp) : "r"(p) : "memory"); |
| 55 | #else |
| 56 | /* No insn known to fault unaligned -- try for a straight load. */ |
| 57 | allow_fail = 1; |
| 58 | tmp = *(volatile int *)p; |
| 59 | #endif |
| 60 | |
| 61 | assert(allow_fail); |
| 62 | |
| 63 | /* |
| 64 | * We didn't see a signal. |
| 65 | * We might as well validate the unaligned load worked. |
| 66 | */ |
| 67 | if (BYTE_ORDER == LITTLE_ENDIAN) { |
| 68 | assert(tmp == 0x13121110); |
| 69 | } else { |
| 70 | assert(tmp == 0x10111213); |
| 71 | } |
| 72 | return EXIT_SUCCESS; |
| 73 | } |