When testing SME only systems I noticed that fp-ptrace does not cope at all well with them, this series fixes the major issues so that the test program completes successfully. The reason I was looking at this is that following the recent round of fixes to ptrace we do not currently offer any mechanism for disabling streaming mode via ptrace, this series brings the program to a point where it tests the currently implemented ABI. A further series allowing the disabling of streaming mode via ptrace will follow.
Signed-off-by: Mark Brown broonie@kernel.org --- Mark Brown (3): kselftest/arm64: Test SME on SME only systems in fp-ptrace kselftest/arm64: Fix SVE write data generation for SME only systems kselftest/arm64: Handle attempts to disable SM on SME only systems
tools/testing/selftests/arm64/fp/fp-ptrace.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- base-commit: 86731a2a651e58953fc949573895f2fa6d456841 change-id: 20250718-arm64-fp-ptrace-sme-only-ab327d7f0d32
Best regards, -- Mark Brown broonie@kernel.org
When checking that the vector extensions are supported fp-ptrace currently only checks for SVE being supported which means that we get into a confused half configured state for SME only systems. Check for SME as well.
Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/fp-ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c index 191c47ca0ed8..d953e9b0ebe5 100644 --- a/tools/testing/selftests/arm64/fp/fp-ptrace.c +++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c @@ -1607,7 +1607,7 @@ int main(void) * Run the test set if there is no SVE or SME, with those we * have to pick a VL for each run. */ - if (!sve_supported()) { + if (!sve_supported() && !sme_supported()) { test_config.sve_vl_in = 0; test_config.sve_vl_expected = 0; test_config.sme_vl_in = 0;
fp-ptrace does not handle SME only systems correctly when generating data, on SME only systems scenarios where we are not in streaming mode will not have an expected vector length. This leads to attempts to do memcpy()s of zero byte arrays which can crash, fix this by skipping generation of SVE data for cases where we do not expect to have an active vector length.
Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/fp-ptrace.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c index d953e9b0ebe5..9fc9dc4adaf9 100644 --- a/tools/testing/selftests/arm64/fp/fp-ptrace.c +++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c @@ -1134,6 +1134,9 @@ static void sve_write_expected(struct test_config *config) int vl = vl_expected(config); int sme_vq = __sve_vq_from_vl(config->sme_vl_expected);
+ if (!vl) + return; + fill_random(z_expected, __SVE_ZREGS_SIZE(__sve_vq_from_vl(vl))); fill_random(p_expected, __SVE_PREGS_SIZE(__sve_vq_from_vl(vl)));
@@ -1161,6 +1164,9 @@ static void sve_write(pid_t child, struct test_config *config) vl = vl_expected(config); vq = __sve_vq_from_vl(vl);
+ if (!vl) + return; + iov.iov_len = SVE_PT_SVE_OFFSET + SVE_PT_SVE_SIZE(vq, SVE_PT_REGS_SVE); iov.iov_base = malloc(iov.iov_len); if (!iov.iov_base) {
The ABI for disabling streaming mode via ptrace is to do a write via the SVE register set. Following the recent round of fixes to the ptrace code we don't support this operation on systems without SVE, which is detected as failures by fp-ptrace. Update the program so that it knows that this operation is not currently supported.
Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/fp-ptrace.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c index 9fc9dc4adaf9..21bc4eac092e 100644 --- a/tools/testing/selftests/arm64/fp/fp-ptrace.c +++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c @@ -1061,6 +1061,9 @@ static bool sve_write_supported(struct test_config *config) if (config->sme_vl_in != config->sme_vl_expected) { return false; } + + if (!sve_supported()) + return false; }
return true;
On Fri, 18 Jul 2025 23:14:49 +0100, Mark Brown wrote:
When testing SME only systems I noticed that fp-ptrace does not cope at all well with them, this series fixes the major issues so that the test program completes successfully. The reason I was looking at this is that following the recent round of fixes to ptrace we do not currently offer any mechanism for disabling streaming mode via ptrace, this series brings the program to a point where it tests the currently implemented ABI. A further series allowing the disabling of streaming mode via ptrace will follow.
[...]
Applied to arm64 (for-next/kselftest), thanks!
[1/3] kselftest/arm64: Test SME on SME only systems in fp-ptrace https://git.kernel.org/arm64/c/b021f45d39f3 [2/3] kselftest/arm64: Fix SVE write data generation for SME only systems https://git.kernel.org/arm64/c/aa7d3c8bc27d [3/3] kselftest/arm64: Handle attempts to disable SM on SME only systems https://git.kernel.org/arm64/c/4752dcc156f2
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