65 lines · c
1#include <signal.h>2#include <stdio.h>3#include <stdlib.h>4 5void handler(int sig) {6 // The kernel only changes a few registers so set them all to something other7 // than the values in sigill() so that we can't fall back to real registers8 // and still pass the test.9#define SETREG(N) "mov x" N ", #" N "+1\n\t"10 asm volatile(11 /* clang-format off */12 /* x0 is used for a parameter */13 SETREG("1") SETREG("2") SETREG("3")14 SETREG("4") SETREG("5") SETREG("6") SETREG("7")15 SETREG("8") SETREG("9") SETREG("10") SETREG("11")16 SETREG("12") SETREG("13") SETREG("14") SETREG("15")17 SETREG("16") SETREG("17") SETREG("18") SETREG("19")18 SETREG("20") SETREG("21") SETREG("22") SETREG("23")19 SETREG("24") SETREG("25") SETREG("26") SETREG("27")20 SETREG("28") // fp/x29 needed for unwiding21 SETREG("30") // 31 is xzr/sp22 /* clang-format on */23 ::24 : /* skipped x0 */ "x1", "x2", "x3", "x4", "x5", "x6", "x7", "x8",25 "x9", "x10", "x11", "x12", "x13", "x14", "x15", "x16", "x17", "x18",26 "x19", "x20", "x21", "x22", "x23", "x24", "x25", "x26", "x27",27 "x28",28 /* skipped fp/x29 */ "x30");29 printf("Set a breakpoint here.\n");30 exit(0);31}32 33static void sigill() {34 // Set all general registers to known values to check35 // that the signal unwind plan sets their locations correctly.36#define SETREG(N) "mov x" N ", #" N "\n\t"37 asm volatile(38 /* clang-format off */39 SETREG("0") SETREG("1") SETREG("2") SETREG("3")40 SETREG("4") SETREG("5") SETREG("6") SETREG("7")41 SETREG("8") SETREG("9") SETREG("10") SETREG("11")42 SETREG("12") SETREG("13") SETREG("14") SETREG("15")43 SETREG("16") SETREG("17") SETREG("18") SETREG("19")44 SETREG("20") SETREG("21") SETREG("22") SETREG("23")45 SETREG("24") SETREG("25") SETREG("26") SETREG("27")46 SETREG("28") SETREG("29") SETREG("30") /* 31 is xzr/sp */47 /* clang-format on */48 ".inst 0x00000000\n\t" // udf #0 (old binutils don't support udf)49 ::50 : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7", "x8", "x9", "x10",51 "x11", "x12", "x13", "x14", "x15", "x16", "x17", "x18", "x19",52 "x20", "x21", "x22", "x23", "x24", "x25", "x26", "x27", "x28",53 "x29", "x30");54}55 56int main() {57 if (signal(SIGILL, handler) == SIG_ERR) {58 perror("signal");59 return 1;60 }61 62 sigill();63 return 2;64}65