eb42297a59
Using mprotect() to change PROT_* does not change the MAP_ANON previously set with mmap(). Our linux-user version of MTE only works with MAP_ANON pages, so losing PAGE_ANON caused MTE to stop working. Reported-by: Stephen Long <steplong@quicinc.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Tested-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
62 lines
1.5 KiB
C
62 lines
1.5 KiB
C
/*
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* Linux kernel fallback API definitions for MTE and test helpers.
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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 <assert.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <signal.h>
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#include <sys/mman.h>
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#include <sys/prctl.h>
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#ifndef PR_SET_TAGGED_ADDR_CTRL
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# define PR_SET_TAGGED_ADDR_CTRL 55
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#endif
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#ifndef PR_TAGGED_ADDR_ENABLE
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# define PR_TAGGED_ADDR_ENABLE (1UL << 0)
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#endif
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#ifndef PR_MTE_TCF_SHIFT
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# define PR_MTE_TCF_SHIFT 1
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# define PR_MTE_TCF_NONE (0UL << PR_MTE_TCF_SHIFT)
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# define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT)
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# define PR_MTE_TCF_ASYNC (2UL << PR_MTE_TCF_SHIFT)
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# define PR_MTE_TAG_SHIFT 3
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#endif
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#ifndef PROT_MTE
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# define PROT_MTE 0x20
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#endif
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#ifndef SEGV_MTEAERR
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# define SEGV_MTEAERR 8
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# define SEGV_MTESERR 9
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#endif
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static void enable_mte(int tcf)
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{
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int r = prctl(PR_SET_TAGGED_ADDR_CTRL,
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PR_TAGGED_ADDR_ENABLE | tcf | (0xfffe << PR_MTE_TAG_SHIFT),
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0, 0, 0);
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if (r < 0) {
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perror("PR_SET_TAGGED_ADDR_CTRL");
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exit(2);
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}
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}
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static void * alloc_mte_mem(size_t size) __attribute__((unused));
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static void * alloc_mte_mem(size_t size)
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{
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void *p = mmap(NULL, size, PROT_READ | PROT_WRITE | PROT_MTE,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (p == MAP_FAILED) {
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perror("mmap PROT_MTE");
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exit(2);
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}
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return p;
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}
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