From c9bb40b7f786662e33d71afe236442b0b61f0446 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 3 Aug 2023 00:46:39 +0100 Subject: arm64/fpsimd: Clear SME state in the target task when setting the VL When setting SME vector lengths we clear TIF_SME to reenable SME traps, doing a reallocation of the backing storage on next use. We do this using clear_thread_flag() which operates on the current thread, meaning that when setting the vector length via ptrace we may both not force traps for the target task and force a spurious flush of any SME state that the tracing task may have. Clear the flag in the target task. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Reported-by: David Spickett Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-tif-sme-v1-1-88312fd6fbfd@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/fpsimd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 520b681a07bb..a61a1fd6492d 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -909,7 +909,7 @@ int vec_set_vector_length(struct task_struct *task, enum vec_type type, */ task->thread.svcr &= ~(SVCR_SM_MASK | SVCR_ZA_MASK); - clear_thread_flag(TIF_SME); + clear_tsk_thread_flag(task, TIF_SME); free_sme = true; } } -- cgit v1.2.3-59-g8ed1b From 89a65c3f170e5c3b05a626046c68354e2afd7912 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 3 Aug 2023 01:19:06 +0100 Subject: arm64/ptrace: Flush FP state when setting ZT0 When setting ZT0 via ptrace we do not currently force a reload of the floating point register state from memory, do that to ensure that the newly set value gets loaded into the registers on next task execution. The function was templated off the function for FPSIMD which due to our providing the option of embedding a FPSIMD regset within the SVE regset does not directly include the flush. Fixes: f90b529bcbe5 ("arm64/sme: Implement ZT0 ptrace support") Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-zt0-flush-v1-1-72e854eaf96e@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/ptrace.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index d7f4f0d1ae12..740e81e9db04 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1180,6 +1180,8 @@ static int zt_set(struct task_struct *target, if (ret == 0) target->thread.svcr |= SVCR_ZA_MASK; + fpsimd_flush_task_state(target); + return ret; } -- cgit v1.2.3-59-g8ed1b From 045aecdfcb2e060db142d83a0f4082380c465d2c Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 3 Aug 2023 19:33:21 +0100 Subject: arm64/ptrace: Don't enable SVE when setting streaming SVE Systems which implement SME without also implementing SVE are architecturally valid but were not initially supported by the kernel, unfortunately we missed one issue in the ptrace code. The SVE register setting code is shared between SVE and streaming mode SVE. When we set full SVE register state we currently enable TIF_SVE unconditionally, in the case where streaming SVE is being configured on a system that supports vanilla SVE this is not an issue since we always initialise enough state for both vector lengths but on a system which only support SME it will result in us attempting to restore the SVE vector length after having set streaming SVE registers. Fix this by making the enabling of SVE conditional on setting SVE vector state. If we set streaming SVE state and SVE was not already enabled this will result in a SVE access trap on next use of normal SVE, this will cause us to flush our register state but this is fine since the only way to trigger a SVE access trap would be to exit streaming mode which will cause the in register state to be flushed anyway. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-1-49df214bfb3e@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/ptrace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 740e81e9db04..5b9b4305248b 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -932,11 +932,13 @@ static int sve_set_common(struct task_struct *target, /* * Ensure target->thread.sve_state is up to date with target's * FPSIMD regs, so that a short copyin leaves trailing - * registers unmodified. Always enable SVE even if going into - * streaming mode. + * registers unmodified. Only enable SVE if we are + * configuring normal SVE, a system with streaming SVE may not + * have normal SVE. */ fpsimd_sync_to_sve(target); - set_tsk_thread_flag(target, TIF_SVE); + if (type == ARM64_VEC_SVE) + set_tsk_thread_flag(target, TIF_SVE); target->thread.fp_type = FP_STATE_SVE; BUILD_BUG_ON(SVE_PT_SVE_OFFSET != sizeof(header)); -- cgit v1.2.3-59-g8ed1b From 507ea5dd92d23fcf10e4d1a68a443c86a49753ed Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 3 Aug 2023 19:33:22 +0100 Subject: arm64/fpsimd: Sync FPSIMD state with SVE for SME only systems Currently we guard FPSIMD/SVE state conversions with a check for the system supporting SVE but SME only systems may need to sync streaming mode SVE state so add a check for SME support too. These functions are only used by the ptrace code. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-2-49df214bfb3e@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/fpsimd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index a61a1fd6492d..bfaa70cb040e 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -679,7 +679,7 @@ static void fpsimd_to_sve(struct task_struct *task) void *sst = task->thread.sve_state; struct user_fpsimd_state const *fst = &task->thread.uw.fpsimd_state; - if (!system_supports_sve()) + if (!system_supports_sve() && !system_supports_sme()) return; vq = sve_vq_from_vl(thread_get_cur_vl(&task->thread)); @@ -705,7 +705,7 @@ static void sve_to_fpsimd(struct task_struct *task) unsigned int i; __uint128_t const *p; - if (!system_supports_sve()) + if (!system_supports_sve() && !system_supports_sme()) return; vl = thread_get_cur_vl(&task->thread); -- cgit v1.2.3-59-g8ed1b From 69af56ae56a48a2522aad906c4461c6c7c092737 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 3 Aug 2023 19:33:23 +0100 Subject: arm64/fpsimd: Sync and zero pad FPSIMD state for streaming SVE We have a function sve_sync_from_fpsimd_zeropad() which is used by the ptrace code to update the SVE state when the user writes to the the FPSIMD register set. Currently this checks that the task has SVE enabled but this will miss updates for tasks which have streaming SVE enabled if SVE has not been enabled for the thread, also do the conversion if the task has streaming SVE enabled. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-3-49df214bfb3e@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/fpsimd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index bfaa70cb040e..75c37b1c55aa 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -835,7 +835,8 @@ void sve_sync_from_fpsimd_zeropad(struct task_struct *task) void *sst = task->thread.sve_state; struct user_fpsimd_state const *fst = &task->thread.uw.fpsimd_state; - if (!test_tsk_thread_flag(task, TIF_SVE)) + if (!test_tsk_thread_flag(task, TIF_SVE) && + !thread_sm_enabled(&task->thread)) return; vq = sve_vq_from_vl(thread_get_cur_vl(&task->thread)); -- cgit v1.2.3-59-g8ed1b