From d9be03256d745360a859b11091e5a43f7828382b Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 11 Jul 2018 14:56:46 +0100 Subject: [PATCH] arm64: don't restore GPRs when context tracking Now that syscalls are invoked with pt_regs, we no longer need to ensure that the argument regsiters are live in the entry assembly, and it's fine to not restore them after context_tracking_user_exit() has corrupted them. Signed-off-by: Mark Rutland Acked-by: Catalin Marinas Cc: Will Deacon Signed-off-by: Will Deacon --- arch/arm64/kernel/entry.S | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 156c4e3..c41b84d 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -41,19 +41,9 @@ * Context tracking subsystem. Used to instrument transitions * between user and kernel mode. */ - .macro ct_user_exit, syscall = 0 + .macro ct_user_exit #ifdef CONFIG_CONTEXT_TRACKING bl context_tracking_user_exit - .if \syscall == 1 - /* - * Save/restore needed during syscalls. Restore syscall arguments from - * the values already saved on stack during kernel_entry. - */ - ldp x0, x1, [sp] - ldp x2, x3, [sp, #S_X2] - ldp x4, x5, [sp, #S_X4] - ldp x6, x7, [sp, #S_X6] - .endif #endif .endm -- 2.7.4