| Age | Commit message (Collapse) | Author | |
|---|---|---|---|
| 2012-09-21 | x86, smap: Add STAC and CLAC instructions to control user space access | H. Peter Anvin | |
| When Supervisor Mode Access Prevention (SMAP) is enabled, access to userspace from the kernel is controlled by the AC flag. To make the performance of manipulating that flag acceptable, there are two new instructions, STAC and CLAC, to set and clear it. This patch adds those instructions, via alternative(), when the SMAP feature is enabled. It also adds X86_EFLAGS_AC unconditionally to the SYSCALL entry mask; there is simply no reason to make that one conditional. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1348256595-29119-9-git-send-email-hpa@linux.intel.com | |||
| 2012-09-21 | x86, smap: Add a header file with macros for STAC/CLAC | H. Peter Anvin | |
| The STAC/CLAC instructions are only available with SMAP, but on the other hand they aren't needed if SMAP is not available, or before we start to run userspace, so construct them as alternatives which start out as noops and are enabled by the alternatives mechanism. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1348256595-29119-7-git-send-email-hpa@linux.intel.com | |||
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index : linaro-lsk.git | |
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