From 05458ee3ff82b31a4564836a84ef20d6c233dfc7 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 27 Dec 2022 17:12:05 +0000 Subject: [PATCH] arm64/signal: Always accept SVE signal frames on SME only systems commit 7dde62f0687c8856b6c0660066c7ee83a6a6f033 upstream. Currently we reject an attempt to restore a SVE signal frame on a system with SME but not SVE supported. This means that it is not possible to disable streaming mode via signal return as this is configured via the flags in the SVE signal context. Instead accept the signal frame, we will require it to have a vector length of 0 specified and no payload since the task will have no SVE vector length configured. Fixes: 85ed24dad290 ("arm64/sme: Implement streaming SVE signal handling") Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20221223-arm64-fix-sme-only-v1-2-938d663f69e5@kernel.org Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/signal.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 5100893..43adbfa 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -280,7 +280,12 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user) vl = task_get_sme_vl(current); } else { - if (!system_supports_sve()) + /* + * A SME only system use SVE for streaming mode so can + * have a SVE formatted context with a zero VL and no + * payload data. + */ + if (!system_supports_sve() && !system_supports_sme()) return -EINVAL; vl = task_get_sve_vl(current); -- 2.7.4