diff options
author | Michael Ellerman <mpe@ellerman.id.au> | 2018-01-02 13:37:36 +0300 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-01-03 08:49:24 +0300 |
commit | 6ed361586b323e576fd5536078fe9f2ee7906e61 (patch) | |
tree | 2eac1cb753abdbae19852cea8595557f7f142341 /tools/testing/selftests/powerpc | |
parent | 5769beaf180a892c3fea92937954727fb912bded (diff) | |
download | linux-6ed361586b323e576fd5536078fe9f2ee7906e61.tar.xz |
selftests/powerpc: Add a test of SEGV error behaviour
Add a test case of the error code reported when we take a SEGV on a
mapped but inaccessible area. We broke this recently.
Based on a test case from John Sperbeck <jsperbeck@google.com>.
Acked-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'tools/testing/selftests/powerpc')
-rw-r--r-- | tools/testing/selftests/powerpc/mm/.gitignore | 3 | ||||
-rw-r--r-- | tools/testing/selftests/powerpc/mm/Makefile | 2 | ||||
-rw-r--r-- | tools/testing/selftests/powerpc/mm/segv_errors.c | 78 |
3 files changed, 81 insertions, 2 deletions
diff --git a/tools/testing/selftests/powerpc/mm/.gitignore b/tools/testing/selftests/powerpc/mm/.gitignore index e715a3f2fbf4..7d7c42ed6de9 100644 --- a/tools/testing/selftests/powerpc/mm/.gitignore +++ b/tools/testing/selftests/powerpc/mm/.gitignore @@ -1,4 +1,5 @@ hugetlb_vs_thp_test subpage_prot tempfile -prot_sao
\ No newline at end of file +prot_sao +segv_errors
\ No newline at end of file diff --git a/tools/testing/selftests/powerpc/mm/Makefile b/tools/testing/selftests/powerpc/mm/Makefile index bf315bcbe663..8ebbe96d80a8 100644 --- a/tools/testing/selftests/powerpc/mm/Makefile +++ b/tools/testing/selftests/powerpc/mm/Makefile @@ -2,7 +2,7 @@ noarg: $(MAKE) -C ../ -TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot prot_sao +TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot prot_sao segv_errors TEST_GEN_FILES := tempfile include ../../lib.mk diff --git a/tools/testing/selftests/powerpc/mm/segv_errors.c b/tools/testing/selftests/powerpc/mm/segv_errors.c new file mode 100644 index 000000000000..06ae76ee3ea1 --- /dev/null +++ b/tools/testing/selftests/powerpc/mm/segv_errors.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright 2017 John Sperbeck + * + * Test that an access to a mapped but inaccessible area causes a SEGV and + * reports si_code == SEGV_ACCERR. + */ + +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <signal.h> +#include <sys/mman.h> +#include <assert.h> +#include <ucontext.h> + +#include "utils.h" + +static bool faulted; +static int si_code; + +static void segv_handler(int n, siginfo_t *info, void *ctxt_v) +{ + ucontext_t *ctxt = (ucontext_t *)ctxt_v; + struct pt_regs *regs = ctxt->uc_mcontext.regs; + + faulted = true; + si_code = info->si_code; + regs->nip += 4; +} + +int test_segv_errors(void) +{ + struct sigaction act = { + .sa_sigaction = segv_handler, + .sa_flags = SA_SIGINFO, + }; + char c, *p = NULL; + + p = mmap(NULL, getpagesize(), 0, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); + FAIL_IF(p == MAP_FAILED); + + FAIL_IF(sigaction(SIGSEGV, &act, NULL) != 0); + + faulted = false; + si_code = 0; + + /* + * We just need a compiler barrier, but mb() works and has the nice + * property of being easy to spot in the disassembly. + */ + mb(); + c = *p; + mb(); + + FAIL_IF(!faulted); + FAIL_IF(si_code != SEGV_ACCERR); + + faulted = false; + si_code = 0; + + mb(); + *p = c; + mb(); + + FAIL_IF(!faulted); + FAIL_IF(si_code != SEGV_ACCERR); + + return 0; +} + +int main(void) +{ + return test_harness(test_segv_errors, "segv_errors"); +} |