* [PATCH] selftests/powerpc: Add a test of SEGV error behaviour
@ 2018-01-02 11:03 Michael Ellerman
2018-01-02 19:41 ` John Sperbeck
2018-01-17 13:30 ` Michael Ellerman
0 siblings, 2 replies; 4+ messages in thread
From: Michael Ellerman @ 2018-01-02 11:03 UTC (permalink / raw)
To: linuxppc-dev; +Cc: jsperbeck, benh
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>.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
tools/testing/selftests/powerpc/mm/.gitignore | 3 +-
tools/testing/selftests/powerpc/mm/Makefile | 2 +-
tools/testing/selftests/powerpc/mm/segv_errors.c | 78 ++++++++++++++++++++++++
3 files changed, 81 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/powerpc/mm/segv_errors.c
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");
+}
--
2.14.3
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] selftests/powerpc: Add a test of SEGV error behaviour
2018-01-02 11:03 [PATCH] selftests/powerpc: Add a test of SEGV error behaviour Michael Ellerman
@ 2018-01-02 19:41 ` John Sperbeck
2018-01-03 6:14 ` Michael Ellerman
2018-01-17 13:30 ` Michael Ellerman
1 sibling, 1 reply; 4+ messages in thread
From: John Sperbeck @ 2018-01-02 19:41 UTC (permalink / raw)
To: Michael Ellerman; +Cc: linuxppc-dev, Benjamin Herrenschmidt
On Tue, Jan 2, 2018 at 3:03 AM, Michael Ellerman <mpe@ellerman.id.au> wrote:
> 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>.
>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
> tools/testing/selftests/powerpc/mm/.gitignore | 3 +-
> tools/testing/selftests/powerpc/mm/Makefile | 2 +-
> tools/testing/selftests/powerpc/mm/segv_errors.c | 78 ++++++++++++++++++++++++
> 3 files changed, 81 insertions(+), 2 deletions(-)
> create mode 100644 tools/testing/selftests/powerpc/mm/segv_errors.c
>
> 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");
> +}
> --
> 2.14.3
>
Looks good to me.
Acked-by: John Sperbeck <jsperbeck@google.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] selftests/powerpc: Add a test of SEGV error behaviour
2018-01-02 19:41 ` John Sperbeck
@ 2018-01-03 6:14 ` Michael Ellerman
0 siblings, 0 replies; 4+ messages in thread
From: Michael Ellerman @ 2018-01-03 6:14 UTC (permalink / raw)
To: John Sperbeck; +Cc: linuxppc-dev, Benjamin Herrenschmidt
John Sperbeck <jsperbeck@google.com> writes:
> On Tue, Jan 2, 2018 at 3:03 AM, Michael Ellerman <mpe@ellerman.id.au> wrote:
>> 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>.
>>
>> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
...
>
> Looks good to me.
>
> Acked-by: John Sperbeck <jsperbeck@google.com>
Thanks.
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: selftests/powerpc: Add a test of SEGV error behaviour
2018-01-02 11:03 [PATCH] selftests/powerpc: Add a test of SEGV error behaviour Michael Ellerman
2018-01-02 19:41 ` John Sperbeck
@ 2018-01-17 13:30 ` Michael Ellerman
1 sibling, 0 replies; 4+ messages in thread
From: Michael Ellerman @ 2018-01-17 13:30 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: jsperbeck
On Tue, 2018-01-02 at 11:03:24 UTC, Michael Ellerman wrote:
> 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>.
>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Acked-by: John Sperbeck <jsperbeck@google.com>
Applied to powerpc next.
https://git.kernel.org/powerpc/c/6ed361586b323e576fd5536078fe9f
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-01-02 11:03 [PATCH] selftests/powerpc: Add a test of SEGV error behaviour Michael Ellerman
2018-01-02 19:41 ` John Sperbeck
2018-01-03 6:14 ` Michael Ellerman
2018-01-17 13:30 ` Michael Ellerman
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