From: Mark Brown Date: Wed, 17 Aug 2022 18:23:24 +0000 (+0100) Subject: arm64/sme: Don't flush SVE register state when handling SME traps X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=714f3cbd70a4db9f9b7fe5b8a032896ed33fb824;p=linux.git 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 --- diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index b9ae9827e6e8e..23834d96d1e78 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(); }