The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 045aecdfcb2e060db142d83a0f4082380c465d2c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023080713-schedule-tuition-b3a5@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
045aecdfcb2e ("arm64/ptrace: Don't enable SVE when setting streaming SVE") baa8515281b3 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE") 93ae6b01bafe ("KVM: arm64: Discard any SVE state when entering KVM guests")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 045aecdfcb2e060db142d83a0f4082380c465d2c Mon Sep 17 00:00:00 2001 From: Mark Brown broonie@kernel.org Date: Thu, 3 Aug 2023 19:33:21 +0100 Subject: [PATCH] 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 broonie@kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-1-49df214... Signed-off-by: Catalin Marinas catalin.marinas@arm.com
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));