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Message-Id: <043e94318b4fc3bccb41845a2b3500bb4c78a21a.1504733277.git.luto@kernel.org>
Date: Wed, 6 Sep 2017 14:36:52 -0700
From: Andy Lutomirski <luto@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org, Borislav Petkov <bp@...en8.de>,
Brian Gerst <brgerst@...il.com>,
Andrew Cooper <andrew.cooper3@...rix.com>,
Juergen Gross <jgross@...e.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Kees Cook <keescook@...omium.org>,
Andy Lutomirski <luto@...nel.org>
Subject: [RFC 07/17] x86/asm/64: Merge the fast and slow SYSRET paths
Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
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 45d4cb8fd81b..a9e318f7cc9b 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -216,9 +216,8 @@ 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
- USERGS_SYSRET64
+ addq $6*8, %rsp
+ jmp .Lpop_c_regs_and_sysret
1:
/*
@@ -309,6 +308,7 @@ return_from_SYSCALL_64:
syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
POP_EXTRA_REGS
+.Lpop_c_regs_and_sysret:
popq %rsi /* skip r11 */
popq %r10
popq %r9
--
2.13.5
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