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| author |   Alexandre Chartre <alexandre.chartre@oracle.com> | 2022-06-14 23:15:50 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2022-06-27 10:33:59 +0200 |
| commit | 7fbf47c7ce50b38a64576b150e7011ae73d54669 (patch) | |
| tree | 8cb177c7abdd79b9f1344be6881ef9a46631a2e2 /Documentation | |
| parent | x86/bugs: Report AMD retbleed vulnerability (diff) | |
| download | linux-dev-7fbf47c7ce50b38a64576b150e7011ae73d54669.tar.xz linux-dev-7fbf47c7ce50b38a64576b150e7011ae73d54669.zip | |
x86/bugs: Add AMD retbleed= boot parameter
Add the "retbleed=<value>" boot parameter to select a mitigation for
RETBleed. Possible values are "off", "auto" and "unret"
(JMP2RET mitigation). The default value is "auto".
Currently, "retbleed=auto" will select the unret mitigation on
AMD and Hygon and no mitigation on Intel (JMP2RET is not effective on
Intel).
[peterz: rebase; add hygon]
[jpoimboe: cleanups]
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2522b11e593f..529613367e7d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5197,6 +5197,21 @@ retain_initrd [RAM] Keep initrd memory after extraction + retbleed= [X86] Control mitigation of RETBleed (Arbitrary + Speculative Code Execution with Return Instructions) + vulnerability. + + off - unconditionally disable + auto - automatically select a migitation + unret - force enable untrained return thunks, + only effective on AMD Zen {1,2} + based systems. + + Selecting 'auto' will choose a mitigation method at run + time according to the CPU. + + Not specifying this option is equivalent to retbleed=auto. + rfkill.default_state= 0 "airplane mode". All wifi, bluetooth, wimax, gps, fm, etc. communication is blocked by default. |