While looking at the BTI selftest results on a non-BTI system I noticed that not only are we printing invalid test numbers in that case, we're skipping running the tests entirely even though there's a well defined ABI we could be verifying and the code already knows what the results should be.
The first patch here is a fix to the reporting of test numbers when skipping, the second one just removes the skipping entirely in favour of a runtime check for what the result of a BTI binary should be.
To: Catalin Marinas catalin.marinas@arm.com To: Will Deacon will@kernel.org To: Shuah Khan shuah@kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kselftest@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Mark Brown broonie@kernel.org
--- Mark Brown (2): kselftest/arm64: Fix test numbering when skipping tests kselftest/arm64: Run BTI selftests on systems without BTI
tools/testing/selftests/arm64/bti/test.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) --- base-commit: b7bfaa761d760e72a969d116517eaa12e404c262 change-id: 20230110-arm64-bti-selftest-skip-9fdf5e94fb62
Best regards,
Currently when skipping tests in the BTI testsuite we assign the same number to every test since we forget to increment the current test number as we skip, causing warnings about not running the expected test count and potentially otherwise confusing result parsers. Fix this by adding an appropriate increment.
Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/bti/test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/arm64/bti/test.c b/tools/testing/selftests/arm64/bti/test.c index 67b77ab83c20..4b6dda987c58 100644 --- a/tools/testing/selftests/arm64/bti/test.c +++ b/tools/testing/selftests/arm64/bti/test.c @@ -112,7 +112,7 @@ static void __do_test(void (*trampoline)(void (*)(void)), if (skip_all) { test_skipped++; putstr("ok "); - putnum(test_num); + putnum(test_num++); putstr(" "); puttestname(name, trampoline_name); putstr(" # SKIP\n");
The BTI selftests are built both with and without BTI support, validating both the generation of BTI signals as expected for binaries without BTI support. Both versions of the binary currently skip all their tests when the system does not support BTI, however this is excessive since we do have a defined ABI for how the programs should function in this case (especially for the non-BTI binary). Update the test program to run all the tests unconditionally, adding a runtime adjustment of the expected results on systems that don't support BTI where we currently handle the build time case.
The tests all use HINT space instructions, BTI itself is a HINT as is are the PAC instructions that function as landing pads, so nothing in the tests depends on support for BTI in the kernel or hardware.
Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/bti/test.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-)
diff --git a/tools/testing/selftests/arm64/bti/test.c b/tools/testing/selftests/arm64/bti/test.c index 4b6dda987c58..2cd8dcee5aec 100644 --- a/tools/testing/selftests/arm64/bti/test.c +++ b/tools/testing/selftests/arm64/bti/test.c @@ -6,6 +6,7 @@
#include "system.h"
+#include <stdbool.h> #include <stddef.h> #include <linux/errno.h> #include <linux/auxvec.h> @@ -101,7 +102,8 @@ static void handler(int n, siginfo_t *si __always_unused, uc->uc_mcontext.pstate &= ~PSR_BTYPE_MASK; }
-static int skip_all; +/* Does the system have BTI? */ +static bool have_bti;
static void __do_test(void (*trampoline)(void (*)(void)), void (*fn)(void), @@ -109,19 +111,11 @@ static void __do_test(void (*trampoline)(void (*)(void)), const char *name, int expect_sigill) { - if (skip_all) { - test_skipped++; - putstr("ok "); - putnum(test_num++); - putstr(" "); - puttestname(name, trampoline_name); - putstr(" # SKIP\n"); - - return; - } - - /* Branch Target exceptions should only happen in BTI binaries: */ - if (!BTI) + /* + * Branch Target exceptions should only happen for BTI + * binaries running on a system with BTI: + */ + if (!BTI || !have_bti) expect_sigill = 0;
sigill_expected = expect_sigill; @@ -199,9 +193,10 @@ void start(int *argcp) putstr("# HWCAP2_BTI present\n"); if (!(hwcap & HWCAP_PACA)) putstr("# Bad hardware? Expect problems.\n"); + have_bti = true; } else { putstr("# HWCAP2_BTI not present\n"); - skip_all = 1; + have_bti = false; }
putstr("# Test binary");
On Tue, 10 Jan 2023 20:49:58 +0000, Mark Brown wrote:
While looking at the BTI selftest results on a non-BTI system I noticed that not only are we printing invalid test numbers in that case, we're skipping running the tests entirely even though there's a well defined ABI we could be verifying and the code already knows what the results should be.
The first patch here is a fix to the reporting of test numbers when skipping, the second one just removes the skipping entirely in favour of a runtime check for what the result of a BTI binary should be.
[...]
Applied to arm64 (for-next/kselftest), thanks!
[1/2] kselftest/arm64: Fix test numbering when skipping tests https://git.kernel.org/arm64/c/30792e7c18b6 [2/2] kselftest/arm64: Run BTI selftests on systems without BTI https://git.kernel.org/arm64/c/1c3b614548b5
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Catalin Marinas -
Mark Brown