Commit-ID: 0336e04a6520bdaefdb0769d2a70084fa52e81ed Gitweb: https://git.kernel.org/tip/0336e04a6520bdaefdb0769d2a70084fa52e81ed Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Fri, 12 Apr 2019 15:39:31 -0500 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Wed, 17 Apr 2019 21:37:29 +0200
s390/speculation: Support 'mitigations=' cmdline option 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 <jpoim...@redhat.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Tested-by: Jiri Kosina <jkos...@suse.cz> (on x86) Reviewed-by: Jiri Kosina <jkos...@suse.cz> Cc: Borislav Petkov <b...@alien8.de> Cc: "H . Peter Anvin" <h...@zytor.com> Cc: Andy Lutomirski <l...@kernel.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Jiri Kosina <ji...@kernel.org> Cc: Waiman Long <long...@redhat.com> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Jon Masters <j...@redhat.com> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Michael Ellerman <m...@ellerman.id.au> Cc: linuxppc-...@lists.ozlabs.org Cc: Martin Schwidefsky <schwidef...@de.ibm.com> Cc: Heiko Carstens <heiko.carst...@de.ibm.com> Cc: linux-s...@vger.kernel.org Cc: Catalin Marinas <catalin.mari...@arm.com> Cc: Will Deacon <will.dea...@arm.com> Cc: linux-arm-ker...@lists.infradead.org Cc: linux-a...@vger.kernel.org Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> Cc: Tyler Hicks <tyhi...@canonical.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Randy Dunlap <rdun...@infradead.org> Cc: Steven Price <steven.pr...@arm.com> Cc: Phil Auld <pa...@redhat.com> Link: https://lkml.kernel.org/r/e4a161805458a5ec88812aac0307ae3908a030fc.1555085500.git.jpoim...@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 ac7150a25a7a..1ae93872b79f 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2514,7 +2514,7 @@ 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. @@ -2525,7 +2525,8 @@ 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.
