From 78b23877dbba7dbcda2b89383d17bed82ce8f663 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 8 May 2025 14:26:41 +0100 Subject: [PATCH 1/5] kselftest/arm64: fp-ptrace: Fix expected FPMR value when PSTATE.SM is changed The fp-ptrace test suite expects that FPMR is set to zero when PSTATE.SM is changed via ptrace, but ptrace has never altered FPMR in this way, and the test logic erroneously relies upon (and has concealed) a bug where task_fpsimd_load() would unexpectedly and non-deterministically clobber FPMR. Using ptrace, FPMR can only be altered by writing to the NT_ARM_FPMR regset. The value of PSTATE.SM can be altered by writing to the NT_ARM_SVE or NT_ARM_SSVE regsets, and/or by changing the SME vector length (when writing to the NT_ARM_SVE, NT_ARM_SSVE, or NT_ARM_ZA regsets), but none of these writes will change the value of FPMR. The task_fpsimd_load() bug was introduced with the initial FPMR support in commit: 203f2b95a882 ("arm64/fpsimd: Support FEAT_FPMR") The incorrect FPMR test code was introduced in commit: 7dbd26d0b22d ("kselftest/arm64: Add FPMR coverage to fp-ptrace") Subsequently, the task_fpsimd_load() bug was fixed in commit: e5fa85fce08b ("arm64/fpsimd: Don't corrupt FPMR when streaming mode changes") ... whereupon the fp-ptrace FPMR tests started failing reliably, e.g. | # # Mismatch in saved FPMR: 915058000 != 0 | # not ok 25 SVE write, SVE 64->64, SME 64/0->64/1 Fix this by changing the test to expect that FPMR is *NOT* changed when PSTATE.SM is changed via ptrace, matching the extant behaviour. I've chosen to update the test code rather than modifying ptrace to zero FPMR when PSTATE.SM changes. Not zeroing FPMR is simpler overall, and allows the NT_ARM_FPMR regset to be handled independently from other regsets, leaving less scope for error. Fixes: 7dbd26d0b22d ("kselftest/arm64: Add FPMR coverage to fp-ptrace") Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: David Spickett Cc: Luis Machado Cc: Marc Zyngier Cc: Mark Brown Cc: Will Deacon Link: https://lore.kernel.org/r/20250508132644.1395904-22-mark.rutland@arm.com Signed-off-by: Will Deacon --- tools/testing/selftests/arm64/fp/fp-ptrace.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c index 4930e03a7b99..762048eb354f 100644 --- a/tools/testing/selftests/arm64/fp/fp-ptrace.c +++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c @@ -891,18 +891,11 @@ static void set_initial_values(struct test_config *config) { int vq = __sve_vq_from_vl(vl_in(config)); int sme_vq = __sve_vq_from_vl(config->sme_vl_in); - bool sm_change; svcr_in = config->svcr_in; svcr_expected = config->svcr_expected; svcr_out = 0; - if (sme_supported() && - (svcr_in & SVCR_SM) != (svcr_expected & SVCR_SM)) - sm_change = true; - else - sm_change = false; - fill_random(&v_in, sizeof(v_in)); memcpy(v_expected, v_in, sizeof(v_in)); memset(v_out, 0, sizeof(v_out)); @@ -953,12 +946,7 @@ static void set_initial_values(struct test_config *config) if (fpmr_supported()) { fill_random(&fpmr_in, sizeof(fpmr_in)); fpmr_in &= FPMR_SAFE_BITS; - - /* Entering or exiting streaming mode clears FPMR */ - if (sm_change) - fpmr_expected = 0; - else - fpmr_expected = fpmr_in; + fpmr_expected = fpmr_in; } else { fpmr_in = 0; fpmr_expected = 0; From be45e63f79ecfea8373f18f50330838d77553a6b Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 8 May 2025 14:26:42 +0100 Subject: [PATCH 2/5] kselftest/arm64: tpidr2: Adjust to new clone() behaviour In order to fix an ABI problem, we recently changed the way that a clone() syscall manipulates TPIDR2 and PSTATE.ZA. Historically the child would inherit the parent's TPIDR2 value unless CLONE_SETTLS was set, and now the child will inherit the parent's TPIDR2 value unless CLONE_VM is set. Update the tpidr2 test for the new behaviour. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Daniel Kiss Cc: Marc Zyngier Cc: Mark Brown Cc: Richard Sandiford Cc: Sander De Smalen Cc: Tamas Petz Cc: Will Deacon Cc: Yury Khrustalev Link: https://lore.kernel.org/r/20250508132644.1395904-23-mark.rutland@arm.com Signed-off-by: Will Deacon --- tools/testing/selftests/arm64/abi/tpidr2.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/arm64/abi/tpidr2.c b/tools/testing/selftests/arm64/abi/tpidr2.c index 285c47dd42f6..eb19dcc37a75 100644 --- a/tools/testing/selftests/arm64/abi/tpidr2.c +++ b/tools/testing/selftests/arm64/abi/tpidr2.c @@ -169,8 +169,10 @@ static int sys_clone(unsigned long clone_flags, unsigned long newsp, child_tidptr); } +#define __STACK_SIZE (8 * 1024 * 1024) + /* - * If we clone with CLONE_SETTLS then the value in the parent should + * If we clone with CLONE_VM then the value in the parent should * be unchanged and the child should start with zero and be able to * set its own value. */ @@ -179,11 +181,19 @@ static int write_clone_read(void) int parent_tid, child_tid; pid_t parent, waiting; int ret, status; + void *stack; parent = getpid(); set_tpidr2(parent); - ret = sys_clone(CLONE_SETTLS, 0, &parent_tid, 0, &child_tid); + stack = malloc(__STACK_SIZE); + if (!stack) { + putstr("# malloc() failed\n"); + return 0; + } + + ret = sys_clone(CLONE_VM, (unsigned long)stack + __STACK_SIZE, + &parent_tid, 0, &child_tid); if (ret == -1) { putstr("# clone() failed\n"); putnum(errno); From 031a2acaa1cdab3c89dfb810a8cb75ddfdf5a65c Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 8 May 2025 14:26:43 +0100 Subject: [PATCH 3/5] kselftest/arm64: fp-ptrace: Adjust to new VL change behaviour In order to fix an ABI problem, we recently changed the way that changing the SVE/SME vector length affects PSTATE.SM. Historically, changing the SME vector length would clear PSTATE.SM. Now, changing the SME vector length preserves PSTATE.SM. Update the fp-ptrace test for the new behaviour. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: David Spickett Cc: Luis Machado Cc: Marc Zyngier Cc: Mark Brown Cc: Will Deacon Link: https://lore.kernel.org/r/20250508132644.1395904-24-mark.rutland@arm.com Signed-off-by: Will Deacon --- tools/testing/selftests/arm64/fp/fp-ptrace.c | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c index 762048eb354f..c2882a5a5cc0 100644 --- a/tools/testing/selftests/arm64/fp/fp-ptrace.c +++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c @@ -1183,18 +1183,8 @@ static void sve_write(pid_t child, struct test_config *config) static bool za_write_supported(struct test_config *config) { - if (config->sme_vl_in != config->sme_vl_expected) { - /* Changing the SME VL exits streaming mode. */ - if (config->svcr_expected & SVCR_SM) { - return false; - } - } else { - /* Otherwise we can't change streaming mode */ - if ((config->svcr_in & SVCR_SM) != - (config->svcr_expected & SVCR_SM)) { - return false; - } - } + if ((config->svcr_in & SVCR_SM) != (config->svcr_expected & SVCR_SM)) + return false; return true; } @@ -1212,10 +1202,8 @@ static void za_write_expected(struct test_config *config) memset(zt_expected, 0, sizeof(zt_expected)); } - /* Changing the SME VL flushes ZT, SVE state and exits SM */ + /* Changing the SME VL flushes ZT, SVE state */ if (config->sme_vl_in != config->sme_vl_expected) { - svcr_expected &= ~SVCR_SM; - sve_vq = __sve_vq_from_vl(vl_expected(config)); memset(z_expected, 0, __SVE_ZREGS_SIZE(sve_vq)); memset(p_expected, 0, __SVE_PREGS_SIZE(sve_vq)); From 864f3ddcd7153fdb3f2d3822e563985135d8eafa Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 8 May 2025 14:26:44 +0100 Subject: [PATCH 4/5] kselftest/arm64: fp-ptrace: Adjust to new inactive mode behaviour In order to fix an ABI problem, we recently changed the way that reads of the NT_ARM_SVE and NT_ARM_SSVE regsets behave when their corresponding vector state is inactive. Update the fp-ptrace test for the new behaviour. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: David Spickett Cc: Luis Machado Cc: Marc Zyngier Cc: Mark Brown Cc: Will Deacon Link: https://lore.kernel.org/r/20250508132644.1395904-25-mark.rutland@arm.com Signed-off-by: Will Deacon --- tools/testing/selftests/arm64/fp/fp-ptrace.c | 30 ++++++++++++++------ 1 file changed, 22 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c index c2882a5a5cc0..191c47ca0ed8 100644 --- a/tools/testing/selftests/arm64/fp/fp-ptrace.c +++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c @@ -439,10 +439,17 @@ static bool check_ptrace_values_sve(pid_t child, struct test_config *config) pass = false; } - if (sve->size != SVE_PT_SIZE(vq, sve->flags)) { - ksft_print_msg("Mismatch in SVE header size: %d != %lu\n", - sve->size, SVE_PT_SIZE(vq, sve->flags)); - pass = false; + if (svcr_in & SVCR_SM) { + if (sve->size != sizeof(sve)) { + ksft_print_msg("NT_ARM_SVE reports data with PSTATE.SM\n"); + pass = false; + } + } else { + if (sve->size != SVE_PT_SIZE(vq, sve->flags)) { + ksft_print_msg("Mismatch in SVE header size: %d != %lu\n", + sve->size, SVE_PT_SIZE(vq, sve->flags)); + pass = false; + } } /* The registers might be in completely different formats! */ @@ -515,10 +522,17 @@ static bool check_ptrace_values_ssve(pid_t child, struct test_config *config) pass = false; } - if (sve->size != SVE_PT_SIZE(vq, sve->flags)) { - ksft_print_msg("Mismatch in SSVE header size: %d != %lu\n", - sve->size, SVE_PT_SIZE(vq, sve->flags)); - pass = false; + if (!(svcr_in & SVCR_SM)) { + if (sve->size != sizeof(sve)) { + ksft_print_msg("NT_ARM_SSVE reports data without PSTATE.SM\n"); + pass = false; + } + } else { + if (sve->size != SVE_PT_SIZE(vq, sve->flags)) { + ksft_print_msg("Mismatch in SSVE header size: %d != %lu\n", + sve->size, SVE_PT_SIZE(vq, sve->flags)); + pass = false; + } } /* The registers might be in completely different formats! */ From b225219a4002aae9b5d71cf0f912ac02d38f0212 Mon Sep 17 00:00:00 2001 From: tanze Date: Thu, 15 May 2025 13:18:39 +0800 Subject: [PATCH 5/5] kselftest/arm64: Set default OUTPUT path when undefined When running 'make' in tools/testing/selftests/arm64/ without explicitly setting the OUTPUT variable, the build system will creates test directories (e.g., /bti) in the root filesystem due to OUTPUT defaulting to an empty string. This causes unintended pollution of the root directory. This patch adds proper handling for the OUTPUT variable: Sets OUTPUT to the current directory (.) if not specified Signed-off-by: tanze Link: https://lore.kernel.org/r/20250515051839.3409658-1-tanze@kylinos.cn Signed-off-by: Will Deacon --- tools/testing/selftests/arm64/Makefile | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile index 22029e60eff3..c4c72ee2ef55 100644 --- a/tools/testing/selftests/arm64/Makefile +++ b/tools/testing/selftests/arm64/Makefile @@ -21,6 +21,8 @@ CFLAGS += $(KHDR_INCLUDES) CFLAGS += -I$(top_srcdir)/tools/include +OUTPUT ?= $(CURDIR) + export CFLAGS export top_srcdir