52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
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/*
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* Memory tagging, basic fail cases, asynchronous signals.
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*
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* Copyright (c) 2021 Linaro Ltd
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "mte.h"
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void pass(int sig, siginfo_t *info, void *uc)
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{
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assert(info->si_code == SEGV_MTEAERR);
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exit(0);
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}
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int main(int ac, char **av)
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{
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struct sigaction sa;
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long *p0, *p1, *p2;
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long excl = 1;
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enable_mte(PR_MTE_TCF_ASYNC);
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p0 = alloc_mte_mem(sizeof(*p0));
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/* Create two differently tagged pointers. */
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asm("irg %0,%1,%2" : "=r"(p1) : "r"(p0), "r"(excl));
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asm("gmi %0,%1,%0" : "+r"(excl) : "r" (p1));
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assert(excl != 1);
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asm("irg %0,%1,%2" : "=r"(p2) : "r"(p0), "r"(excl));
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assert(p1 != p2);
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/* Store the tag from the first pointer. */
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asm("stg %0, [%0]" : : "r"(p1));
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*p1 = 0;
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memset(&sa, 0, sizeof(sa));
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sa.sa_sigaction = pass;
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sa.sa_flags = SA_SIGINFO;
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sigaction(SIGSEGV, &sa, NULL);
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/*
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* Signal for async error will happen eventually.
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* For a real kernel this should be after the next IRQ (e.g. timer).
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* For qemu linux-user, we kick the cpu and exit at the next TB.
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* In either case, loop until this happens (or killed by timeout).
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* For extra sauce, yield, producing EXCP_YIELD to cpu_loop().
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*/
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asm("str %0, [%0]; yield" : : "r"(p2));
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while (1);
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}
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