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authorFenghua Yu <fenghua.yu@intel.com>2011-05-12 03:51:05 +0400
committerH. Peter Anvin <hpa@linux.intel.com>2011-05-18 08:22:00 +0400
commitde5397ad5b9ad22e2401c4dacdf1bb3b19c05679 (patch)
treee8c612c4f84efe458d8ec3c23f1bfd834f20c0f2 /Documentation/kernel-parameters.txt
parentdc23c0bccf5eea171c87b3db285d032b9a5f06c4 (diff)
downloadlinux-de5397ad5b9ad22e2401c4dacdf1bb3b19c05679.tar.xz
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.txt4
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)