diff options
| author | Kees Cook <keescook@chromium.org> | 2018-05-03 14:37:54 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-22 16:58:02 +0200 |
| commit | 05a85a396f3989e9ac953785d9dccfc7cd0110f2 (patch) | |
| tree | 7636561963031b056f6bb829e0682bb9f9449582 /Documentation/kernel-parameters.txt | |
| parent | 094c2767c4f02c36eabc27309d78b04f4a216e88 (diff) | |
x86/speculation: Make "seccomp" the default mode for Speculative Store Bypass
commit f21b53b20c754021935ea43364dbf53778eeba32 upstream
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>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 543923b35260..52240a63132e 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3997,19 +3997,27 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 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= |