1 /* 2 * Memory tagging, basic fail cases, asynchronous signals. 3 * 4 * Copyright (c) 2021 Linaro Ltd 5 * SPDX-License-Identifier: GPL-2.0-or-later 6 */ 7 8 #include "mte.h" 9 10 void pass(int sig, siginfo_t *info, void *uc) 11 { 12 assert(info->si_code == SEGV_MTEAERR); 13 exit(0); 14 } 15 16 int main(int ac, char **av) 17 { 18 struct sigaction sa; 19 long *p0, *p1, *p2; 20 long excl = 1; 21 22 enable_mte(PR_MTE_TCF_ASYNC); 23 p0 = alloc_mte_mem(sizeof(*p0)); 24 25 /* Create two differently tagged pointers. */ 26 asm("irg %0,%1,%2" : "=r"(p1) : "r"(p0), "r"(excl)); 27 asm("gmi %0,%1,%0" : "+r"(excl) : "r" (p1)); 28 assert(excl != 1); 29 asm("irg %0,%1,%2" : "=r"(p2) : "r"(p0), "r"(excl)); 30 assert(p1 != p2); 31 32 /* Store the tag from the first pointer. */ 33 asm("stg %0, [%0]" : : "r"(p1)); 34 35 *p1 = 0; 36 37 memset(&sa, 0, sizeof(sa)); 38 sa.sa_sigaction = pass; 39 sa.sa_flags = SA_SIGINFO; 40 sigaction(SIGSEGV, &sa, NULL); 41 42 /* 43 * Signal for async error will happen eventually. 44 * For a real kernel this should be after the next IRQ (e.g. timer). 45 * For qemu linux-user, we kick the cpu and exit at the next TB. 46 * In either case, loop until this happens (or killed by timeout). 47 * For extra sauce, yield, producing EXCP_YIELD to cpu_loop(). 48 */ 49 asm("str %0, [%0]; yield" : : "r"(p2)); 50 while (1); 51 } 52