From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932499AbdJZI11 (ORCPT ); Thu, 26 Oct 2017 04:27:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:40534 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932468AbdJZI1X (ORCPT ); Thu, 26 Oct 2017 04:27:23 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA23D2192D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org From: Andy Lutomirski To: X86 ML Cc: Borislav Petkov , "linux-kernel@vger.kernel.org" , Brian Gerst , Dave Hansen , Linus Torvalds , Andy Lutomirski Subject: [PATCH 07/18] x86/asm/64: Merge the fast and slow SYSRET paths Date: Thu, 26 Oct 2017 01:26:39 -0700 Message-Id: <998a8c2c39546115f93e4c6e2ad7f918626f6145.1509006199.git.luto@kernel.org> X-Mailer: git-send-email 2.13.6 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org They did almost the same thing. Remove a bunch of pointless instructions (mostly hidden in macros) and reduce cognitive load by merging them. Signed-off-by: Andy Lutomirski --- arch/x86/entry/entry_64.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 9dafafa3e0ec..c855ee91a3a5 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -220,10 +220,9 @@ entry_SYSCALL_64_fastpath: TRACE_IRQS_ON /* user mode is traced as IRQs on */ movq RIP(%rsp), %rcx movq EFLAGS(%rsp), %r11 - RESTORE_C_REGS_EXCEPT_RCX_R11 - movq RSP(%rsp), %rsp + addq $6*8, %rsp /* skip extra regs -- they were preserved */ UNWIND_HINT_EMPTY - USERGS_SYSRET64 + jmp .Lpop_c_regs_except_rcx_r11_and_sysret 1: /* @@ -315,6 +314,7 @@ syscall_return_via_sysret: /* rcx and r11 are already restored (see code above) */ UNWIND_HINT_EMPTY POP_EXTRA_REGS +.Lpop_c_regs_except_rcx_r11_and_sysret: popq %rsi /* skip r11 */ popq %r10 popq %r9 -- 2.13.6