From 1769c0df602ce2a1f9504b08c545f0a39285a5fe Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 7 Dec 2021 16:32:50 +0000 Subject: [PATCH] arm64/fp: Add comments documenting the usage of state restore functions Add comments to help people figure out when fpsimd_bind_state_to_cpu() and fpsimd_update_current_state() are used. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20211207163250.1373542-1-broonie@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/fpsimd.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index fa244c426f610..aad59051b3b76 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1213,7 +1213,8 @@ void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st, void *sve_state, /* * Load the userland FPSIMD state of 'current' from memory, but only if the * FPSIMD state already held in the registers is /not/ the most recent FPSIMD - * state of 'current' + * state of 'current'. This is called when we are preparing to return to + * userspace to ensure that userspace sees a good register state. */ void fpsimd_restore_current_state(void) { @@ -1244,7 +1245,9 @@ void fpsimd_restore_current_state(void) /* * Load an updated userland FPSIMD state for 'current' from memory and set the * flag that indicates that the FPSIMD register contents are the most recent - * FPSIMD state of 'current' + * FPSIMD state of 'current'. This is used by the signal code to restore the + * register state when returning from a signal handler in FPSIMD only cases, + * any SVE context will be discarded. */ void fpsimd_update_current_state(struct user_fpsimd_state const *state) { -- 2.39.5