| 1 | #include <stddef.h> |
| 2 | #include <stdio.h> |
| 3 | #include <string.h> |
| 4 | #include <sys/mman.h> |
| 5 | |
| 6 | #define DEFINE_ASM(_name, _code) \ |
| 7 | extern const char _name[]; \ |
| 8 | extern const char _name ## _end[]; \ |
| 9 | asm(" .globl " #_name "\n" \ |
| 10 | #_name ":\n" \ |
| 11 | " " _code "\n" \ |
| 12 | " .globl " #_name "_end\n" \ |
| 13 | #_name "_end:\n"); |
| 14 | |
| 15 | DEFINE_ASM(br_r14, "br %r14"); |
| 16 | DEFINE_ASM(brasl_r0, "brasl %r0,-0x100000000"); |
| 17 | DEFINE_ASM(brcl_0xf, "brcl 0xf,-0x100000000"); |
| 18 | |
| 19 | struct test { |
| 20 | const char *code; |
| 21 | const char *code_end; |
| 22 | }; |
| 23 | |
| 24 | static const struct test tests[] = { |
| 25 | { |
| 26 | .code = brasl_r0, |
| 27 | .code_end = brasl_r0_end, |
| 28 | }, |
| 29 | { |
| 30 | .code = brcl_0xf, |
| 31 | .code_end = brcl_0xf_end, |
| 32 | }, |
| 33 | }; |
| 34 | |
| 35 | int main(void) |
| 36 | { |
| 37 | unsigned char *buf; |
| 38 | size_t length = 0; |
| 39 | size_t i; |
| 40 | |
| 41 | for (i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) { |
| 42 | size_t test_length = 0x100000000 + (tests[i].code_end - tests[i].code); |
| 43 | |
| 44 | if (test_length > length) { |
| 45 | length = test_length; |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | buf = mmap(NULL, length, PROT_READ | PROT_WRITE | PROT_EXEC, |
| 50 | MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0); |
| 51 | if (buf == MAP_FAILED) { |
| 52 | perror("SKIP: mmap() failed"); |
| 53 | return 0; |
| 54 | } |
| 55 | |
| 56 | memcpy(buf, br_r14, br_r14_end - br_r14); |
| 57 | for (i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) { |
| 58 | void (*code)(void) = (void *)(buf + 0x100000000); |
| 59 | |
| 60 | memcpy(code, tests[i].code, tests[i].code_end - tests[i].code); |
| 61 | code(); |
| 62 | memset(code, 0, tests[i].code_end - tests[i].code); |
| 63 | } |
| 64 | |
| 65 | munmap(buf, length); |
| 66 | |
| 67 | return 0; |
| 68 | } |