From: Josh Poimboeuf <jpoimboe@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Kosina <jikos@kernel.org>, Waiman Long <longman@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Jon Masters <jcm@redhat.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
linuxppc-dev@lists.ozlabs.org,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
linux-s390@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Tyler Hicks <tyhicks@canonical.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH RFC 4/5] s390/speculation: Add support for 'cpu_spec_mitigations=' cmdline options
Date: Thu, 4 Apr 2019 11:44:14 -0500 [thread overview]
Message-ID: <a887ee8cd195939c377ba60aac9e5c792809e447.1554396090.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1554396090.git.jpoimboe@redhat.com>
Configure s390 runtime CPU speculation bug mitigations in accordance
with the 'cpu_spec_mitigations=' cmdline options. 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 | 7 ++++---
arch/s390/kernel/nospec-branch.c | 4 +++-
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 0e8eae1e8a25..e838af96daa4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2554,8 +2554,9 @@
Disable all speculative CPU mitigations.
Equivalent to: nopti [x86, powerpc]
nospectre_v1 [powerpc]
- nospectre_v2 [x86]
+ nospectre_v2 [x86, powerpc, s390]
spectre_v2_user=off [x86]
+ nobp=0 [s390]
spec_store_bypass_disable=off [x86, powerpc]
l1tf=off [x86]
@@ -2567,7 +2568,7 @@
upgrades, or who have other ways of avoiding
SMT-based attacks.
Equivalent to: pti=auto [x86]
- spectre_v2=auto [x86]
+ spectre_v2=auto [x86, s390]
spectre_v2_user=auto [x86]
spec_store_bypass_disable=auto [x86, powerpc]
l1tf=flush [x86]
@@ -2578,7 +2579,7 @@
always want to be fully mitigated, even if it
means losing SMT.
Equivalent to: pti=auto [x86]
- spectre_v2=auto [x86]
+ spectre_v2=auto [x86, s390]
spectre_v2_user=auto [x86]
spec_store_bypass_disable=auto [x86, powerpc]
l1tf=flush,nosmt [x86]
diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c
index bdddaae96559..c40eb672b43a 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 +59,8 @@ early_param("nospectre_v2", nospectre_v2_setup_early);
void __init nospec_auto_detect(void)
{
- if (test_facility(156)) {
+ if (test_facility(156) ||
+ cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) {
/*
* The machine supports etokens.
* Disable expolines and disable nobp.
--
2.17.2
next prev parent reply other threads:[~2019-04-04 16:45 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-04 16:44 [PATCH RFC 0/5] cpu/speculation: Add 'cpu_spec_mitigations=' cmdline options Josh Poimboeuf
2019-04-04 16:44 ` [PATCH RFC 1/5] " Josh Poimboeuf
2019-04-04 16:49 ` Josh Poimboeuf
2019-04-05 13:12 ` Borislav Petkov
2019-04-05 14:20 ` Josh Poimboeuf
2019-04-05 15:20 ` Borislav Petkov
2019-04-05 16:01 ` Borislav Petkov
2019-04-05 16:18 ` Josh Poimboeuf
2019-04-10 5:48 ` Michael Ellerman
2019-04-10 8:30 ` Borislav Petkov
2019-04-10 12:10 ` Thomas Gleixner
2019-04-11 13:15 ` Josh Poimboeuf
2019-04-12 2:41 ` Michael Ellerman
2019-04-12 2:29 ` Michael Ellerman
2019-04-04 16:44 ` [PATCH RFC 2/5] x86/speculation: Add support for " Josh Poimboeuf
2019-04-05 13:57 ` Borislav Petkov
2019-04-05 14:31 ` Josh Poimboeuf
2019-04-05 15:26 ` Borislav Petkov
2019-04-05 16:05 ` Josh Poimboeuf
2019-04-05 15:18 ` Randy Dunlap
2019-04-05 15:30 ` Josh Poimboeuf
2019-04-04 16:44 ` [PATCH RFC 3/5] powerpc/speculation: " Josh Poimboeuf
2019-04-04 19:49 ` Jiri Kosina
2019-04-04 20:01 ` Timothy Pearson
2019-04-10 6:06 ` Michael Ellerman
2019-04-11 4:02 ` Josh Poimboeuf
2019-04-04 16:44 ` Josh Poimboeuf [this message]
2019-04-04 16:44 ` [PATCH RFC 5/5] arm64/speculation: " Josh Poimboeuf
2019-04-05 14:39 ` Steven Price
2019-04-05 14:43 ` Josh Poimboeuf
2019-04-05 14:44 ` Will Deacon
2019-04-05 16:03 ` Josh Poimboeuf
2019-04-04 16:50 ` [PATCH RFC 0/5] cpu/speculation: Add " Waiman Long
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