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| author | Fenghua Yu <fenghua.yu@intel.com> | 2011-05-11 16:51:05 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2011-05-17 21:22:00 -0700 |
| commit | de5397ad5b9ad22e2401c4dacdf1bb3b19c05679 (patch) | |
| tree | e8c612c4f84efe458d8ec3c23f1bfd834f20c0f2 /Documentation/kernel-parameters.txt | |
| parent | dc23c0bccf5eea171c87b3db285d032b9a5f06c4 (diff) | |
| download | lwn-de5397ad5b9ad22e2401c4dacdf1bb3b19c05679.tar.gz lwn-de5397ad5b9ad22e2401c4dacdf1bb3b19c05679.zip | |
x86, cpu: Enable/disable Supervisor Mode Execution Protection
Enable/disable newly documented SMEP (Supervisor Mode Execution Protection) CPU
feature in kernel. CR4.SMEP (bit 20) is 0 at power-on. If the feature is
supported by CPU (X86_FEATURE_SMEP), enable SMEP by setting CR4.SMEP. New kernel
option nosmep disables the feature even if the feature is supported by CPU.
[ hpa: moved the call to setup_smep() until after the vendor-specific
initialization; that ensures that CPUID features are unmasked. We
will still run it before we have userspace (never mind uncontrolled
userspace). ]
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
LKML-Reference: <1305157865-31727-1-git-send-email-fenghua.yu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index cc85a9278190..56fb8c16e20b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1664,6 +1664,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. noexec=on: enable non-executable mappings (default) noexec=off: disable non-executable mappings + nosmep [X86] + Disable SMEP (Supervisor Mode Execution Protection) + even if it is supported by processor. + noexec32 [X86-64] This affects only 32-bit executables. noexec32=on: enable non-executable mappings (default) |