Commit 61da7c8e authored by Mark Brown's avatar Mark Brown Committed by Will Deacon
Browse files

arm64/signal: Don't assume that TIF_SVE means we saved SVE state 



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: 8c845e27 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch")
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240130-arm64-sve-signal-regs-v2-1-9fc6f9502782@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 54be6c6c

arch/arm64/kernel/fpsimd.c

+1 −1
Original line number Diff line number Diff line
@@ -1635,7 +1635,7 @@ 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);

}

arch/arm64/kernel/signal.c

+2 −2
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ static int preserve_sve_context(struct sve_context __user *ctx) 
		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 rt_sigframe_user_layout *user, 
	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(&current->thread)) {

			int vl = max(sve_max_vl(), sme_max_vl());