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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-23 18:01:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-23 18:01:31 -0700 |
| commit | c5a3d3c01e90e74166f95eec9db6fcc3ba72a9d6 (patch) | |
| tree | 3f938013952aaf28beab3e6228a4c4e5aa90badf /Documentation/admin-guide | |
| parent | Merge tag 'x86_tdx_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| parent | x86/speculation: Add missing prototype for unpriv_ebpf_notify() (diff) | |
| download | linux-dev-c5a3d3c01e90e74166f95eec9db6fcc3ba72a9d6.tar.xz linux-dev-c5a3d3c01e90e74166f95eec9db6fcc3ba72a9d6.zip | |
Merge tag 'x86_cpu_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 CPU feature updates from Borislav Petkov:
- Remove a bunch of chicken bit options to turn off CPU features which
are not really needed anymore
- Misc fixes and cleanups
* tag 'x86_cpu_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Add missing prototype for unpriv_ebpf_notify()
x86/pm: Fix false positive kmemleak report in msr_build_context()
x86/speculation/srbds: Do not try to turn mitigation off when not supported
x86/cpu: Remove "noclflush"
x86/cpu: Remove "noexec"
x86/cpu: Remove "nosmep"
x86/cpu: Remove CONFIG_X86_SMAP and "nosmap"
x86/cpu: Remove "nosep"
x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid=
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0c648a867dfa..1169a4acfeb1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -631,12 +631,17 @@ Defaults to zero when built as a module and to 10 seconds when built into the kernel. - clearcpuid=BITNUM[,BITNUM...] [X86] + clearcpuid=X[,X...] [X86] Disable CPUID feature X for the kernel. See arch/x86/include/asm/cpufeatures.h for the valid bit - numbers. Note the Linux specific bits are not necessarily - stable over kernel options, but the vendor specific + numbers X. Note the Linux-specific bits are not necessarily + stable over kernel options, but the vendor-specific ones should be. + X can also be a string as appearing in the flags: line + in /proc/cpuinfo which does not have the above + instability issue. However, not all features have names + in /proc/cpuinfo. + Note that using this option will taint your kernel. Also note that user programs calling CPUID directly or using the feature without checking anything will still see it. This just prevents it from @@ -3478,8 +3483,6 @@ nocache [ARM] - noclflush [BUGS=X86] Don't use the CLFLUSH instruction - delayacct [KNL] Enable per-task delay accounting nodsp [SH] Disable hardware DSP at boot time. @@ -3490,16 +3493,11 @@ noexec [IA-64] - noexec [X86] - On X86-32 available only on PAE configured kernels. - noexec=on: enable non-executable mappings (default) - noexec=off: disable non-executable mappings - - nosmap [X86,PPC] + nosmap [PPC] Disable SMAP (Supervisor Mode Access Prevention) even if it is supported by processor. - nosmep [X86,PPC64s] + nosmep [PPC64s] Disable SMEP (Supervisor Mode Execution Prevention) even if it is supported by processor. @@ -3699,8 +3697,6 @@ nosbagart [IA-64] - nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support. - nosgx [X86-64,SGX] Disables Intel SGX kernel support. nosmp [SMP] Tells an SMP kernel to act as a UP kernel, |