From: Josh Poimboeuf <jpoimboe@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Paul Mackerras <paulus@samba.org>,
"H . Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-s390@vger.kernel.org, x86@kernel.org,
Will Deacon <will.deacon@arm.com>,
Steven Price <steven.price@arm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Waiman Long <longman@redhat.com>,
linux-arch@vger.kernel.org, Jon Masters <jcm@redhat.com>,
Jiri Kosina <jikos@kernel.org>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
Phil Auld <pauld@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Randy Dunlap <rdunlap@infradead.org>,
Tyler Hicks <tyhicks@canonical.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 4/5] s390/speculation: Support 'mitigations=' cmdline option
Date: Fri, 12 Apr 2019 15:39:31 -0500 [thread overview]
Message-ID: <e4a161805458a5ec88812aac0307ae3908a030fc.1555085500.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1555085500.git.jpoimboe@redhat.com>
Configure s390 runtime CPU speculation bug mitigations in accordance
with the 'mitigations=' cmdline option. This affects Spectre v1 and
Spectre v2.
The default behavior is unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
Documentation/admin-guide/kernel-parameters.txt | 5 +++--
arch/s390/kernel/nospec-branch.c | 3 ++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a03ab62b69af..e84a01d90e92 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2545,7 +2545,7 @@
http://repo.or.cz/w/linux-2.6/mini2440.git
mitigations=
- [X86,PPC] Control optional mitigations for CPU
+ [X86,PPC,S390] 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.
@@ -2556,7 +2556,8 @@
expose users to several CPU vulnerabilities.
Equivalent to: nopti [X86,PPC]
nospectre_v1 [PPC]
- nospectre_v2 [X86,PPC]
+ nobp=0 [S390]
+ nospectre_v2 [X86,PPC,S390]
spectre_v2_user=off [X86]
spec_store_bypass_disable=off [X86,PPC]
l1tf=off [X86]
diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c
index bdddaae96559..649135cbedd5 100644
--- a/arch/s390/kernel/nospec-branch.c
+++ b/arch/s390/kernel/nospec-branch.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/module.h>
#include <linux/device.h>
+#include <linux/cpu.h>
#include <asm/nospec-branch.h>
static int __init nobp_setup_early(char *str)
@@ -58,7 +59,7 @@ early_param("nospectre_v2", nospectre_v2_setup_early);
void __init nospec_auto_detect(void)
{
- if (test_facility(156)) {
+ if (test_facility(156) || cpu_mitigations_off()) {
/*
* The machine supports etokens.
* Disable expolines and disable nobp.
--
2.17.2
next prev parent reply other threads:[~2019-04-12 20:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-12 20:39 [PATCH v2 0/5] cpu/speculation: Add 'mitigations=' cmdline option Josh Poimboeuf
2019-04-12 20:39 ` [PATCH v2 1/5] " Josh Poimboeuf
2019-04-16 14:13 ` Borislav Petkov
2019-04-16 15:32 ` Josh Poimboeuf
2019-04-12 20:39 ` [PATCH v2 2/5] x86/speculation: Support " Josh Poimboeuf
2019-04-12 20:39 ` [PATCH v2 3/5] powerpc/speculation: " Josh Poimboeuf
2019-04-12 20:39 ` Josh Poimboeuf [this message]
2019-04-12 20:39 ` [PATCH v2 5/5] arm64/speculation: " Josh Poimboeuf
2019-04-12 23:34 ` Randy Dunlap
2019-04-13 3:56 ` [PATCH] Documentation: Add ARM64 to kernel-parameters.rst Josh Poimboeuf
2019-04-13 4:47 ` Randy Dunlap
2019-05-03 12:37 ` Jonathan Corbet
2019-05-03 12:39 ` Will Deacon
2019-05-03 12:47 ` Jonathan Corbet
2019-05-03 13:00 ` Will Deacon
2019-04-16 19:26 ` [PATCH v2 5/5] arm64/speculation: Support 'mitigations=' cmdline option Thomas Gleixner
2019-04-16 20:21 ` Josh Poimboeuf
2019-04-16 21:39 ` Will Deacon
2019-04-24 14:16 ` Will Deacon
2019-04-24 18:19 ` Thomas Gleixner
2019-04-16 7:53 ` [PATCH v2 0/5] cpu/speculation: Add " Jiri Kosina
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