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Message-Id: <20190515090731.402525457@linuxfoundation.org>
Date: Wed, 15 May 2019 12:55:55 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Josh Poimboeuf <jpoimboe@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Jiri Kosina <jkosina@...e.cz>, Borislav Petkov <bp@...en8.de>,
"H . Peter Anvin" <hpa@...or.com>,
Andy Lutomirski <luto@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Jiri Kosina <jikos@...nel.org>,
Waiman Long <longman@...hat.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Jon Masters <jcm@...hat.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
linuxppc-dev@...ts.ozlabs.org,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
linux-s390@...r.kernel.org,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
linux-arm-kernel@...ts.infradead.org, linux-arch@...r.kernel.org,
Tyler Hicks <tyhicks@...onical.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Randy Dunlap <rdunlap@...radead.org>,
Steven Price <steven.price@....com>,
Phil Auld <pauld@...hat.com>,
Ben Hutchings <ben@...adent.org.uk>
Subject: [PATCH 4.4 248/266] x86/speculation: Support mitigations= cmdline option
From: Josh Poimboeuf <jpoimboe@...hat.com>
commit d68be4c4d31295ff6ae34a8ddfaa4c1a8ff42812 upstream.
Configure x86 runtime CPU speculation bug mitigations in accordance with
the 'mitigations=' cmdline option. This affects Meltdown, Spectre v2,
Speculative Store Bypass, and L1TF.
The default behavior is unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Jiri Kosina <jkosina@...e.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@...e.cz>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H . Peter Anvin" <hpa@...or.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Jiri Kosina <jikos@...nel.org>
Cc: Waiman Long <longman@...hat.com>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: Jon Masters <jcm@...hat.com>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: linuxppc-dev@...ts.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
Cc: Heiko Carstens <heiko.carstens@...ibm.com>
Cc: linux-s390@...r.kernel.org
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-arch@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Tyler Hicks <tyhicks@...onical.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Randy Dunlap <rdunlap@...radead.org>
Cc: Steven Price <steven.price@....com>
Cc: Phil Auld <pauld@...hat.com>
Link: https://lkml.kernel.org/r/6616d0ae169308516cfdf5216bedd169f8a8291b.1555085500.git.jpoimboe@redhat.com
[bwh: Backported to 4.4:
- Drop the auto,nosmt option and the l1tf mitigation selection, which we can't
support
- Adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
Documentation/kernel-parameters.txt | 14 +++++++++-----
arch/x86/kernel/cpu/bugs.c | 6 ++++--
arch/x86/mm/kaiser.c | 4 +++-
3 files changed, 16 insertions(+), 8 deletions(-)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2174,15 +2174,19 @@ bytes respectively. Such letter suffixes
http://repo.or.cz/w/linux-2.6/mini2440.git
mitigations=
- Control optional mitigations for CPU vulnerabilities.
- This is a set of curated, arch-independent options, each
- of which is an aggregation of existing arch-specific
- options.
+ [X86] Control optional mitigations for CPU
+ vulnerabilities. This is a set of curated,
+ arch-independent options, each of which is an
+ aggregation of existing arch-specific options.
off
Disable all optional CPU mitigations. This
improves system performance, but it may also
expose users to several CPU vulnerabilities.
+ Equivalent to: nopti [X86]
+ nospectre_v2 [X86]
+ spectre_v2_user=off [X86]
+ spec_store_bypass_disable=off [X86]
auto (default)
Mitigate all CPU vulnerabilities, but leave SMT
@@ -2190,7 +2194,7 @@ bytes respectively. Such letter suffixes
users who don't want to be surprised by SMT
getting disabled across kernel upgrades, or who
have other ways of avoiding SMT-based attacks.
- This is the default behavior.
+ Equivalent to: (default behavior)
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -479,7 +479,8 @@ static enum spectre_v2_mitigation_cmd __
char arg[20];
int ret, i;
- if (cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+ if (cmdline_find_option_bool(boot_command_line, "nospectre_v2") ||
+ cpu_mitigations_off())
return SPECTRE_V2_CMD_NONE;
ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg));
@@ -743,7 +744,8 @@ static enum ssb_mitigation_cmd __init ss
char arg[20];
int ret, i;
- if (cmdline_find_option_bool(boot_command_line, "nospec_store_bypass_disable")) {
+ if (cmdline_find_option_bool(boot_command_line, "nospec_store_bypass_disable") ||
+ cpu_mitigations_off()) {
return SPEC_STORE_BYPASS_CMD_NONE;
} else {
ret = cmdline_find_option(boot_command_line, "spec_store_bypass_disable",
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -10,6 +10,7 @@
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
+#include <linux/cpu.h>
#undef pr_fmt
#define pr_fmt(fmt) "Kernel/User page tables isolation: " fmt
@@ -297,7 +298,8 @@ void __init kaiser_check_boottime_disabl
goto skip;
}
- if (cmdline_find_option_bool(boot_command_line, "nopti"))
+ if (cmdline_find_option_bool(boot_command_line, "nopti") ||
+ cpu_mitigations_off())
goto disable;
skip:
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