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| author | Thomas Gleixner <tglx@linutronix.de> | 2018-11-25 19:33:54 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-14 19:19:39 +0200 |
| commit | 91d9bbd3e4bdb0494ba1d2922646cabb6b8e6e2b (patch) | |
| tree | f808a4fa4b2ba3f8a844fb561c6b7b1718ed6b3a /Documentation | |
| parent | 2d99bc055e458eaaf78e4901e78961546eecf5f4 (diff) | |
| download | linux-stable-91d9bbd3e4bdb0494ba1d2922646cabb6b8e6e2b.tar.gz linux-stable-91d9bbd3e4bdb0494ba1d2922646cabb6b8e6e2b.tar.bz2 linux-stable-91d9bbd3e4bdb0494ba1d2922646cabb6b8e6e2b.zip | |
x86/speculation: Enable prctl mode for spectre_v2_user
commit 7cc765a67d8e04ef7d772425ca5a2a1e2b894c15 upstream.
Now that all prerequisites are in place:
- Add the prctl command line option
- Default the 'auto' mode to 'prctl'
- When SMT state changes, update the static key which controls the
conditional STIBP evaluation on context switch.
- At init update the static key which controls the conditional IBPB
evaluation on context switch.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Waiman Long <longman9394@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Stewart <david.c.stewart@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20181125185005.958421388@linutronix.de
[bwh: Backported to 4.9: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index cef2cb9cbf8a..f87e4bf2ab25 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -4075,9 +4075,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. off - Unconditionally disable mitigations. Is enforced by spectre_v2=off + prctl - Indirect branch speculation is enabled, + but mitigation can be enabled via prctl + per thread. The mitigation control state + is inherited on fork. + auto - Kernel selects the mitigation depending on the available CPU features and vulnerability. - Default is off. + Default is prctl. Not specifying this option is equivalent to spectre_v2_user=auto. |