74 lines
2.9 KiB
Diff
74 lines
2.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
|
From: Rudolf Marek <r.marek@assembler.cz>
|
|
Date: Tue, 28 Nov 2017 22:01:06 +0100
|
|
Subject: [PATCH] x86: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD
|
|
MIME-Version: 1.0
|
|
Content-Type: text/plain; charset=UTF-8
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
CVE-2017-5754
|
|
|
|
[ Note, this is a Git cherry-pick of the following commit:
|
|
|
|
2b67799bdf25 ("x86: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD")
|
|
|
|
... for easier x86 PTI code testing and back-porting. ]
|
|
|
|
The latest AMD AMD64 Architecture Programmer's Manual
|
|
adds a CPUID feature XSaveErPtr (CPUID_Fn80000008_EBX[2]).
|
|
|
|
If this feature is set, the FXSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES
|
|
/ FXRSTOR, XRSTOR, XRSTORS always save/restore error pointers,
|
|
thus making the X86_BUG_FXSAVE_LEAK workaround obsolete on such CPUs.
|
|
|
|
Signed-Off-By: Rudolf Marek <r.marek@assembler.cz>
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
Reviewed-by: Borislav Petkov <bp@suse.de>
|
|
Tested-by: Borislav Petkov <bp@suse.de>
|
|
Cc: Andy Lutomirski <luto@amacapital.net>
|
|
Link: https://lkml.kernel.org/r/bdcebe90-62c5-1f05-083c-eba7f08b2540@assembler.cz
|
|
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
(cherry picked from commit f2dbad36c55e5d3a91dccbde6e8cae345fe5632f)
|
|
Signed-off-by: Andy Whitcroft <apw@canonical.com>
|
|
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
|
|
(cherry picked from commit 281b622113c66ba2de9b7725e1d232ea3c282114)
|
|
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
|
|
---
|
|
arch/x86/include/asm/cpufeatures.h | 1 +
|
|
arch/x86/kernel/cpu/amd.c | 7 +++++--
|
|
2 files changed, 6 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
|
|
index 0ea630bb3e74..d57a174ec97c 100644
|
|
--- a/arch/x86/include/asm/cpufeatures.h
|
|
+++ b/arch/x86/include/asm/cpufeatures.h
|
|
@@ -265,6 +265,7 @@
|
|
/* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */
|
|
#define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */
|
|
#define X86_FEATURE_IRPERF (13*32+ 1) /* Instructions Retired Count */
|
|
+#define X86_FEATURE_XSAVEERPTR (13*32+ 2) /* Always save/restore FP error pointers */
|
|
|
|
/* Thermal and Power Management Leaf, CPUID level 0x00000006 (EAX), word 14 */
|
|
#define X86_FEATURE_DTHERM (14*32+ 0) /* Digital Thermal Sensor */
|
|
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
|
|
index 3b9e220621f8..2a5328cc03a6 100644
|
|
--- a/arch/x86/kernel/cpu/amd.c
|
|
+++ b/arch/x86/kernel/cpu/amd.c
|
|
@@ -760,8 +760,11 @@ static void init_amd(struct cpuinfo_x86 *c)
|
|
case 0x15: init_amd_bd(c); break;
|
|
}
|
|
|
|
- /* Enable workaround for FXSAVE leak */
|
|
- if (c->x86 >= 6)
|
|
+ /*
|
|
+ * Enable workaround for FXSAVE leak on CPUs
|
|
+ * without a XSaveErPtr feature
|
|
+ */
|
|
+ if ((c->x86 >= 6) && (!cpu_has(c, X86_FEATURE_XSAVEERPTR)))
|
|
set_cpu_bug(c, X86_BUG_FXSAVE_LEAK);
|
|
|
|
cpu_detect_cache_sizes(c);
|
|
--
|
|
2.14.2
|
|
|