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>,
Randy Dunlap <rdunlap@infradead.org>,
Steven Price <steven.price@arm.com>, Phil Auld <pauld@redhat.com>
Subject: [PATCH v2 5/5] arm64/speculation: Support 'mitigations=' cmdline option
Date: Fri, 12 Apr 2019 15:39:32 -0500 [thread overview]
Message-ID: <24039e1370ed57e8075730c0b88c505afd9e0ab7.1555085500.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1555085500.git.jpoimboe@redhat.com>
Configure arm64 runtime CPU speculation bug mitigations in accordance
with the 'mitigations=' cmdline option. This affects Meltdown, Spectre
v2, and Speculative Store Bypass.
The default behavior is unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
NOTE: This is based on top of Jeremy Linton's patches:
https://lkml.kernel.org/r/20190410231237.52506-1-jeremy.linton@arm.com
Documentation/admin-guide/kernel-parameters.txt | 8 +++++---
arch/arm64/kernel/cpu_errata.c | 6 +++++-
arch/arm64/kernel/cpufeature.c | 8 +++++++-
3 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index e84a01d90e92..79bfc755defe 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2545,8 +2545,8 @@
http://repo.or.cz/w/linux-2.6/mini2440.git
mitigations=
- [X86,PPC,S390] Control optional mitigations for CPU
- vulnerabilities. This is a set of curated,
+ [X86,PPC,S390,ARM64] 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.
@@ -2555,11 +2555,13 @@
improves system performance, but it may also
expose users to several CPU vulnerabilities.
Equivalent to: nopti [X86,PPC]
+ kpti=0 [ARM64]
nospectre_v1 [PPC]
nobp=0 [S390]
- nospectre_v2 [X86,PPC,S390]
+ nospectre_v2 [X86,PPC,S390,ARM64]
spectre_v2_user=off [X86]
spec_store_bypass_disable=off [X86,PPC]
+ ssbd=force-off [ARM64]
l1tf=off [X86]
auto (default)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index a1f3188c7be0..65bcd7f0cca1 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -19,6 +19,7 @@
#include <linux/arm-smccc.h>
#include <linux/psci.h>
#include <linux/types.h>
+#include <linux/cpu.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/cpufeature.h>
@@ -405,6 +406,9 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
this_cpu_safe = true;
}
+ if (cpu_mitigations_off())
+ ssbd_state = ARM64_SSBD_FORCE_DISABLE;
+
if (psci_ops.smccc_version == SMCCC_VERSION_1_0) {
ssbd_state = ARM64_SSBD_UNKNOWN;
if (!this_cpu_safe)
@@ -599,7 +603,7 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope)
}
/* forced off */
- if (__nospectre_v2) {
+ if (__nospectre_v2 || cpu_mitigations_off()) {
pr_info_once("spectrev2 mitigation disabled by command line option\n");
__hardenbp_enab = false;
return false;
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6b7e1556460a..d826b17f7820 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -25,6 +25,7 @@
#include <linux/stop_machine.h>
#include <linux/types.h>
#include <linux/mm.h>
+#include <linux/cpu.h>
#include <asm/cpu.h>
#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
@@ -966,7 +967,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
MIDR_ALL_VERSIONS(MIDR_HISI_TSV110),
{ /* sentinel */ }
};
- char const *str = "command line option";
+ char const *str = "kpti command line option";
bool meltdown_safe;
meltdown_safe = is_midr_in_range_list(read_cpuid_id(), kpti_safe_list);
@@ -988,6 +989,11 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
__kpti_forced = -1;
}
+ if (cpu_mitigations_off() && !__kpti_forced) {
+ str = "mitigations=off";
+ __kpti_forced = -1;
+ }
+
/* Useful for KASLR robustness */
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) {
if (!__kpti_forced) {
--
2.17.2
next prev parent reply other threads:[~2019-04-12 20:40 UTC|newest]
Thread overview: 25+ 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
2019-04-17 20:01 ` [tip:core/speculation] " tip-bot for Josh Poimboeuf
2019-04-12 20:39 ` [PATCH v2 2/5] x86/speculation: Support " Josh Poimboeuf
2019-04-17 20:02 ` [tip:core/speculation] " tip-bot for Josh Poimboeuf
2019-04-12 20:39 ` [PATCH v2 3/5] powerpc/speculation: " Josh Poimboeuf
2019-04-17 20:02 ` [tip:core/speculation] " tip-bot for Josh Poimboeuf
2019-04-12 20:39 ` [PATCH v2 4/5] s390/speculation: " Josh Poimboeuf
2019-04-17 20:03 ` [tip:core/speculation] " tip-bot for Josh Poimboeuf
2019-04-12 20:39 ` Josh Poimboeuf [this message]
2019-04-12 23:34 ` [PATCH v2 5/5] arm64/speculation: " 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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