From 714f3cbd70a4db9f9b7fe5b8a032896ed33fb824 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Wed, 17 Aug 2022 19:23:24 +0100 Subject: [PATCH] arm64/sme: Don't flush SVE register state when handling SME traps Currently as part of handling a SME access trap we flush the SVE register state. This is not needed and would corrupt register state if the task has access to the SVE registers already. For non-streaming mode accesses the required flushing will be done in the SVE access trap. For streaming mode SVE register accesses the architecture guarantees that the register state will be flushed when streaming mode is entered or exited so there is no need for us to do so. Simply remove the register initialisation. Fixes: 8bd7f91c03d8 ("arm64/sme: Implement traps and syscall handling for SME") Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20220817182324.638214-5-broonie@kernel.org Signed-off-by: Will Deacon --- arch/arm64/kernel/fpsimd.c | 11 ----------- 1 file changed, 11 deletions(-) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index b9ae982..23834d9 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1462,17 +1462,6 @@ void do_sme_acc(unsigned long esr, struct pt_regs *regs) fpsimd_bind_task_to_cpu(); } - /* - * If SVE was not already active initialise the SVE registers, - * any non-shared state between the streaming and regular SVE - * registers is architecturally guaranteed to be zeroed when - * we enter streaming mode. We do not need to initialize ZA - * since ZA must be disabled at this point and enabling ZA is - * architecturally defined to zero ZA. - */ - if (system_supports_sve() && !test_thread_flag(TIF_SVE)) - sve_init_regs(); - put_cpu_fpsimd_context(); } -- 2.7.4