pve-kernel-thunderx/patches/kernel/0095-x86-entry-64-Merge-the-fast-and-slow-SYSRET-paths.patch
Fabian Grünbichler a0f7ab8a6a fix #1622: i40e memory leak
cherry-pick from upstream 4.14
2018-01-19 12:43:16 +01:00

60 lines
2.1 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@kernel.org>
Date: Thu, 2 Nov 2017 00:59:04 -0700
Subject: [PATCH] x86/entry/64: Merge the fast and slow SYSRET paths
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CVE-2017-5754
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 <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1204e20233fcab9130a1ba80b3b1879b5db3fc1f.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit a512210643da8082cb44181dba8b18e752bd68f0)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit 7c4575d8bb2d01960ba9b9840fa22460e0179eca)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
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 33a416c7df2d..87be1cd1fa88 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:
/*
@@ -317,6 +316,7 @@ 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
--
2.14.2