6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mark Brown broonie@kernel.org
commit 61da7c8e2a602f66be578cbbcebe8638c10e0f48 upstream.
When we are in a syscall we will only save the FPSIMD subset even though the task still has access to the full register set, and on context switch we will only remove TIF_SVE when loading the register state. This means that the signal handling code should not assume that TIF_SVE means that the register state is stored in SVE format, it should instead check the format that was recorded during save.
Fixes: 8c845e273104 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch") Signed-off-by: Mark Brown broonie@kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240130-arm64-sve-signal-regs-v2-1-9fc6f9502782@k... Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kernel/fpsimd.c | 2 +- arch/arm64/kernel/signal.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)
--- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1686,7 +1686,7 @@ void fpsimd_preserve_current_state(void) void fpsimd_signal_preserve_current_state(void) { fpsimd_preserve_current_state(); - if (test_thread_flag(TIF_SVE)) + if (current->thread.fp_type == FP_STATE_SVE) sve_to_fpsimd(current); }
--- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -242,7 +242,7 @@ static int preserve_sve_context(struct s vl = task_get_sme_vl(current); vq = sve_vq_from_vl(vl); flags |= SVE_SIG_FLAG_SM; - } else if (test_thread_flag(TIF_SVE)) { + } else if (current->thread.fp_type == FP_STATE_SVE) { vq = sve_vq_from_vl(vl); }
@@ -878,7 +878,7 @@ static int setup_sigframe_layout(struct if (system_supports_sve() || system_supports_sme()) { unsigned int vq = 0;
- if (add_all || test_thread_flag(TIF_SVE) || + if (add_all || current->thread.fp_type == FP_STATE_SVE || thread_sm_enabled(¤t->thread)) { int vl = max(sve_max_vl(), sme_max_vl());