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| | 'Retpoline' mitigation technique for Spectre (branch target injection)
[CVE-2017-5715]:
https://security.googleblog.com/2018/01/more-details-about-mitigations-for-cpu_4.html
https://support.google.com/faqs/answer/7625886
https://spectreattack.com/
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5715
Patch copied from the 'retpoline-regnames' branch of upstream source repository
(please keep an eye for new branches or updates for existing branches):
http://git.infradead.org/users/dwmw2/gcc-retpoline.git
From ec4a7ca4051bb5cbefe03a2e1fb690b9738b8c6d Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 28 Nov 2017 10:26:35 -0800
Subject: [PATCH 03/10] i386: More use reference of struct ix86_frame to avoid
copy
When there is no need to make a copy of ix86_frame, we can use reference
of struct ix86_frame to avoid copy.
Backport from mainline
* config/i386/i386.c (ix86_expand_prologue): Use reference of
struct ix86_frame.
(ix86_expand_epilogue): Likewise.
---
gcc/config/i386/i386.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 397ef7cac26..986e6d79584 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -13667,7 +13667,6 @@ ix86_expand_prologue (void)
{
struct machine_function *m = cfun->machine;
rtx insn, t;
- struct ix86_frame frame;
HOST_WIDE_INT allocate;
bool int_registers_saved;
bool sse_registers_saved;
@@ -13691,7 +13690,7 @@ ix86_expand_prologue (void)
m->fs.sp_valid = true;
ix86_compute_frame_layout ();
- frame = m->frame;
+ struct ix86_frame &frame = cfun->machine->frame;
if (!TARGET_64BIT && ix86_function_ms_hook_prologue (current_function_decl))
{
@@ -14354,13 +14353,12 @@ ix86_expand_epilogue (int style)
{
struct machine_function *m = cfun->machine;
struct machine_frame_state frame_state_save = m->fs;
- struct ix86_frame frame;
bool restore_regs_via_mov;
bool using_drap;
ix86_finalize_stack_realign_flags ();
ix86_compute_frame_layout ();
- frame = m->frame;
+ struct ix86_frame &frame = cfun->machine->frame;
m->fs.sp_valid = (!frame_pointer_needed
|| (crtl->sp_is_unchanging
--
2.15.1
|