diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 77 | ||||
| -rw-r--r-- | Documentation/admin-guide/pm/cpufreq.rst | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/security-bugs.rst | 21 |
3 files changed, 80 insertions, 20 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 81d1d5a74728..70384d8682ea 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -856,7 +856,8 @@ causing system reset or hang due to sending INIT from AP to BSP. - disable_counter_freezing [HW] + perf_v4_pmi= [X86,INTEL] + Format: <bool> Disable Intel PMU counter freezing feature. The feature only exists starting from Arch Perfmon v4 (Skylake and newer). @@ -1682,12 +1683,12 @@ By default, super page will be supported if Intel IOMMU has the capability. With this option, super page will not be supported. - ecs_off [Default Off] - By default, extended context tables will be supported if - the hardware advertises that it has support both for the - extended tables themselves, and also PASID support. With - this option set, extended tables will not be used even - on hardware which claims to support them. + sm_off [Default Off] + By default, scalable mode will be supported if the + hardware advertises that it has support for the scalable + mode translation. With this option set, scalable mode + will not be used even on hardware which claims to support + it. tboot_noforce [Default Off] Do not force the Intel IOMMU enabled under tboot. By default, tboot will force Intel IOMMU on, which @@ -3504,6 +3505,10 @@ before loading. See Documentation/blockdev/ramdisk.txt. + psi= [KNL] Enable or disable pressure stall information + tracking. + Format: <bool> + psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to probe for; one of (bare|imps|exps|lifebook|any). psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports @@ -4194,9 +4199,13 @@ spectre_v2= [X86] Control mitigation of Spectre variant 2 (indirect branch speculation) vulnerability. + The default operation protects the kernel from + user space attacks. - on - unconditionally enable - off - unconditionally disable + on - unconditionally enable, implies + spectre_v2_user=on + off - unconditionally disable, implies + spectre_v2_user=off auto - kernel detects whether your CPU model is vulnerable @@ -4206,6 +4215,12 @@ CONFIG_RETPOLINE configuration option, and the compiler with which the kernel was built. + Selecting 'on' will also enable the mitigation + against user space to user space task attacks. + + Selecting 'off' will disable both the kernel and + the user space protections. + Specific mitigations can also be selected manually: retpoline - replace indirect branches @@ -4215,6 +4230,48 @@ Not specifying this option is equivalent to spectre_v2=auto. + spectre_v2_user= + [X86] Control mitigation of Spectre variant 2 + (indirect branch speculation) vulnerability between + user space tasks + + on - Unconditionally enable mitigations. Is + enforced by spectre_v2=on + + 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. + + prctl,ibpb + - Like "prctl" above, but only STIBP is + controlled per thread. IBPB is issued + always when switching between different user + space processes. + + seccomp + - Same as "prctl" above, but all seccomp + threads will enable the mitigation unless + they explicitly opt out. + + seccomp,ibpb + - Like "seccomp" above, but only STIBP is + controlled per thread. IBPB is issued + always when switching between different + user space processes. + + auto - Kernel selects the mitigation depending on + the available CPU features and vulnerability. + + Default mitigation: + If CONFIG_SECCOMP=y then "seccomp", otherwise "prctl" + + Not specifying this option is equivalent to + spectre_v2_user=auto. + spec_store_bypass_disable= [HW] Control Speculative Store Bypass (SSB) Disable mitigation (Speculative Store Bypass vulnerability) @@ -4713,6 +4770,8 @@ prevent spurious wakeup); n = USB_QUIRK_DELAY_CTRL_MSG (Device needs a pause after every control message); + o = USB_QUIRK_HUB_SLOW_RESET (Hub needs extra + delay after resetting its port); Example: quirks=0781:5580:bk,0a5c:5834:gij usbhid.mousepoll= diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst index 47153e64dfb5..7eca9026a9ed 100644 --- a/Documentation/admin-guide/pm/cpufreq.rst +++ b/Documentation/admin-guide/pm/cpufreq.rst @@ -150,7 +150,7 @@ data structures necessary to handle the given policy and, possibly, to add a governor ``sysfs`` interface to it. Next, the governor is started by invoking its ``->start()`` callback. -That callback it expected to register per-CPU utilization update callbacks for +That callback is expected to register per-CPU utilization update callbacks for all of the online CPUs belonging to the given policy with the CPU scheduler. The utilization update callbacks will be invoked by the CPU scheduler on important events, like task enqueue and dequeue, on every iteration of the diff --git a/Documentation/admin-guide/security-bugs.rst b/Documentation/admin-guide/security-bugs.rst index 164bf71149fd..30187d49dc2c 100644 --- a/Documentation/admin-guide/security-bugs.rst +++ b/Documentation/admin-guide/security-bugs.rst @@ -32,16 +32,17 @@ Disclosure and embargoed information The security list is not a disclosure channel. For that, see Coordination below. -Once a robust fix has been developed, our preference is to release the -fix in a timely fashion, treating it no differently than any of the other -thousands of changes and fixes the Linux kernel project releases every -month. - -However, at the request of the reporter, we will postpone releasing the -fix for up to 5 business days after the date of the report or after the -embargo has lifted; whichever comes first. The only exception to that -rule is if the bug is publicly known, in which case the preference is to -release the fix as soon as it's available. +Once a robust fix has been developed, the release process starts. Fixes +for publicly known bugs are released immediately. + +Although our preference is to release fixes for publicly undisclosed bugs +as soon as they become available, this may be postponed at the request of +the reporter or an affected party for up to 7 calendar days from the start +of the release process, with an exceptional extension to 14 calendar days +if it is agreed that the criticality of the bug requires more time. The +only valid reason for deferring the publication of a fix is to accommodate +the logistics of QA and large scale rollouts which require release +coordination. Whilst embargoed information may be shared with trusted individuals in order to develop a fix, such information will not be published alongside |