Richard Henderson | 36cd5fb | 2021-02-12 10:49:02 -0800 | [diff] [blame] | 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 | } |