x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU
This sets the bit in 'cr4' to actually enable the protection
keys feature. We also include a boot-time disable for the
feature "nopku".
Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE cpuid
bit to appear set. At this point in boot, identify_cpu()
has already run the actual CPUID instructions and populated
the "cpu features" structures. We need to go back and
re-run identify_cpu() to make sure it gets updated values.
We *could* simply re-populate the 11th word of the cpuid
data, but this is probably quick enough.
Also note that with the cpu_has() check and X86_FEATURE_PKU
present in disabled-features.h, we do not need an #ifdef
for setup_pku().
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210229.6708027C@viggo.jf.intel.com
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a37b5bb..acf467d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -976,6 +976,9 @@
See Documentation/x86/intel_mpx.txt for more
information about the feature.
+ nopku [X86] Disable Memory Protection Keys CPU feature found
+ in some Intel CPUs.
+
eagerfpu= [X86]
on enable eager fpu restore
off disable eager fpu restore