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| author |   Josh Poimboeuf <jpoimboe@redhat.com> | 2019-04-12 15:39:31 -0500 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-14 19:18:46 +0200 |
| commit | 91788fcb21d008b1b7ac6beae20522725fa78239 (patch) | |
| tree | 1d5c007fa1e6e3eec0b5969506588b84fab3a9ca /arch | |
| parent | powerpc/speculation: Support 'mitigations=' cmdline option (diff) | |
| download | linux-stable-91788fcb21d008b1b7ac6beae20522725fa78239.tar.xz linux-stable-91788fcb21d008b1b7ac6beae20522725fa78239.zip | |
s390/speculation: Support 'mitigations=' cmdline option
commit 0336e04a6520bdaefdb0769d2a70084fa52e81ed upstream
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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/e4a161805458a5ec88812aac0307ae3908a030fc.1555085500.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/nospec-branch.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c index d5eed651b5ab..83e597688562 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/facility.h> #include <asm/nospec-branch.h> @@ -55,8 +56,16 @@ static int __init nospectre_v2_setup_early(char *str) } early_param("nospectre_v2", nospectre_v2_setup_early); + void __init nospec_auto_detect(void) { + if (cpu_mitigations_off()) { + /* + * Disable expolines and disable nobp. + */ + if (IS_ENABLED(CC_USING_EXPOLINE)) + nospec_disable = 1; + __clear_facility(82, S390_lowcore.alt_stfle_fac_list); if (IS_ENABLED(CC_USING_EXPOLINE)) { /* * The kernel has been compiled with expolines. |