| /* |
| * Branch target identification, basic notskip cases. |
| */ |
| |
| #include <stdio.h> |
| #include <signal.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <sys/mman.h> |
| |
| #ifndef PROT_BTI |
| #define PROT_BTI 0x10 |
| #endif |
| |
| static void skip2_sigill(int sig, siginfo_t *info, void *vuc) |
| { |
| ucontext_t *uc = vuc; |
| uc->uc_mcontext.pc += 8; |
| uc->uc_mcontext.pstate = 1; |
| } |
| |
| #define NOP "nop" |
| #define BTI_N "hint #32" |
| #define BTI_C "hint #34" |
| #define BTI_J "hint #36" |
| #define BTI_JC "hint #38" |
| |
| #define BTYPE_1(DEST) \ |
| "mov x1, #1\n\t" \ |
| "adr x16, 1f\n\t" \ |
| "br x16\n" \ |
| "1: " DEST "\n\t" \ |
| "mov x1, #0" |
| |
| #define BTYPE_2(DEST) \ |
| "mov x1, #1\n\t" \ |
| "adr x16, 1f\n\t" \ |
| "blr x16\n" \ |
| "1: " DEST "\n\t" \ |
| "mov x1, #0" |
| |
| #define BTYPE_3(DEST) \ |
| "mov x1, #1\n\t" \ |
| "adr x15, 1f\n\t" \ |
| "br x15\n" \ |
| "1: " DEST "\n\t" \ |
| "mov x1, #0" |
| |
| #define TEST(WHICH, DEST, EXPECT) \ |
| WHICH(DEST) "\n" \ |
| ".if " #EXPECT "\n\t" \ |
| "eor x1, x1," #EXPECT "\n" \ |
| ".endif\n\t" \ |
| "add x0, x0, x1\n\t" |
| |
| asm("\n" |
| "test_begin:\n\t" |
| BTI_C "\n\t" |
| "mov x2, x30\n\t" |
| "mov x0, #0\n\t" |
| |
| TEST(BTYPE_1, NOP, 1) |
| TEST(BTYPE_1, BTI_N, 1) |
| TEST(BTYPE_1, BTI_C, 0) |
| TEST(BTYPE_1, BTI_J, 0) |
| TEST(BTYPE_1, BTI_JC, 0) |
| |
| TEST(BTYPE_2, NOP, 1) |
| TEST(BTYPE_2, BTI_N, 1) |
| TEST(BTYPE_2, BTI_C, 0) |
| TEST(BTYPE_2, BTI_J, 1) |
| TEST(BTYPE_2, BTI_JC, 0) |
| |
| TEST(BTYPE_3, NOP, 1) |
| TEST(BTYPE_3, BTI_N, 1) |
| TEST(BTYPE_3, BTI_C, 1) |
| TEST(BTYPE_3, BTI_J, 0) |
| TEST(BTYPE_3, BTI_JC, 0) |
| |
| "ret x2\n" |
| "test_end:" |
| ); |
| |
| int main() |
| { |
| struct sigaction sa; |
| void *tb, *te; |
| |
| void *p = mmap(0, getpagesize(), |
| PROT_EXEC | PROT_READ | PROT_WRITE | PROT_BTI, |
| MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| if (p == MAP_FAILED) { |
| perror("mmap"); |
| return 1; |
| } |
| |
| memset(&sa, 0, sizeof(sa)); |
| sa.sa_sigaction = skip2_sigill; |
| sa.sa_flags = SA_SIGINFO; |
| if (sigaction(SIGILL, &sa, NULL) < 0) { |
| perror("sigaction"); |
| return 1; |
| } |
| |
| /* |
| * ??? With "extern char test_begin[]", some compiler versions |
| * will use :got references, and some linker versions will |
| * resolve this reference to a static symbol incorrectly. |
| * Bypass this error by using a pc-relative reference directly. |
| */ |
| asm("adr %0, test_begin; adr %1, test_end" : "=r"(tb), "=r"(te)); |
| |
| memcpy(p, tb, te - tb); |
| |
| return ((int (*)(void))p)(); |
| } |