There are two CPUID bits for protection keys. One is for whether
the CPU contains the feature, and the other will appear set once
the OS enables protection keys. Specifically:
Bit 04: OSPKE. If 1, OS has set CR4.PKE to enable
Protection keys (and the RDPKRU/WRPKRU instructions)
This is because userspace can not see CR4 contents, but it can
see CPUID contents.
X86_FEATURE_PKU is referred to as "PKU" in the hardware documentation:
CPUID.(EAX=07H,ECX=0H):ECX.PKU [bit 3]
X86_FEATURE_OSPKE is "OSPKU":
CPUID.(EAX=07H,ECX=0H):ECX.OSPKE [bit 4]
These are the first CPU features which need to look at the
ECX word in CPUID leaf 0x7, so this patch also includes
fetching that word in to the cpuinfo->x86_capability[] array.
Add it to the disabled-features mask when its config option is
off. Even though we are not using it here, we also extend the
REQUIRED_MASK_BIT_SET() macro to keep it mirroring the
DISABLED_MASK_BIT_SET() version.
This means that in almost all code, you should use:
cpu_has(c, X86_FEATURE_PKU)
and *not* the CONFIG option.
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/20160212210201.7714C250@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add MOVBE to asm/required-features.h so we check for it during startup
and don't bother checking for it later.
CONFIG_MATOM is used because it corresponds to -march=atom in the
Makefiles. If the rules get more complicated it may be necessary to
make this an explicit Kconfig option which uses -mmovbe/-mno-movbe to
control the use of this instruction explicitly.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Link: http://lkml.kernel.org/r/1359395390.3529.65.camel@shinybook.infradead.org
[ hpa: added a patch description ]
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Intel has defined CPUID leaf 7 as the next set of feature flags (see
the AVX specification, version 007). Add support for this new feature
flags word.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <tip-*@vger.kernel.org>
A paravirtualized system may not have PSE or PGE available to
guests, so they are not required features. However, without
paravirt we can assume that any x86-64 implementation will have
them available.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
PGE may not be available when running paravirtualized, so test the cpuid
bit before using it.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:
a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Dave Hansen