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| author |   Kees Cook <keescook@chromium.org> | 2018-05-03 14:37:54 -0700 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2018-05-05 00:51:45 +0200 |
| commit | f21b53b20c754021935ea43364dbf53778eeba32 (patch) | |
| tree | 56c873b4f7dc9b7561858f8e7e4a6bfc2ba8eeeb /Documentation | |
| parent | seccomp: Move speculation migitation control to arch code (diff) | |
| download | linux-dev-f21b53b20c754021935ea43364dbf53778eeba32.tar.xz linux-dev-f21b53b20c754021935ea43364dbf53778eeba32.zip | |
x86/speculation: Make "seccomp" the default mode for Speculative Store Bypass
Unless explicitly opted out of, anything running under seccomp will have
SSB mitigations enabled. Choosing the "prctl" mode will disable this.
[ tglx: Adjusted it to the new arch_seccomp_spec_mitigate() mechanism ]
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index a8d2ae1e335b..f2040d46f095 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4049,19 +4049,27 @@ This parameter controls whether the Speculative Store Bypass optimization is used. - on - Unconditionally disable Speculative Store Bypass - off - Unconditionally enable Speculative Store Bypass - auto - Kernel detects whether the CPU model contains an - implementation of Speculative Store Bypass and - picks the most appropriate mitigation. - prctl - Control Speculative Store Bypass per thread - via prctl. Speculative Store Bypass is enabled - for a process by default. The state of the control - is inherited on fork. + on - Unconditionally disable Speculative Store Bypass + off - Unconditionally enable Speculative Store Bypass + auto - Kernel detects whether the CPU model contains an + implementation of Speculative Store Bypass and + picks the most appropriate mitigation. If the + CPU is not vulnerable, "off" is selected. If the + CPU is vulnerable the default mitigation is + architecture and Kconfig dependent. See below. + prctl - Control Speculative Store Bypass per thread + via prctl. Speculative Store Bypass is enabled + for a process by default. The state of the control + is inherited on fork. + seccomp - Same as "prctl" above, but all seccomp threads + will disable SSB unless they explicitly opt out. Not specifying this option is equivalent to spec_store_bypass_disable=auto. + Default mitigations: + X86: If CONFIG_SECCOMP=y "seccomp", otherwise "prctl" + spia_io_base= [HW,MTD] spia_fio_base= spia_pedr= |