• Dave Hansen's avatar
    x86/cpufeature, x86/mm/pkeys: Add protection keys related CPUID definitions · dfb4a70f
    Dave Hansen authored
    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: default avatarDave Hansen <dave.hansen@linux.intel.com>
    Reviewed-by: default avatarThomas 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.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    dfb4a70f
required-features.h 2.58 KB