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x86/mm/pkeys: Add PTE bits for storing protection key 

Previous documentation has referred to these 4 bits as "ignored".
That means that software could have made use of them.  But, as
far as I know, the kernel never used them.

They are still ignored when protection keys is not enabled, so
they could theoretically still get used for software purposes.

We also implement "empty" versions so that code that references
to them can be optimized away by the compiler when the config
option is not enabled.

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/20160212210205.81E33ED6@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dave Hansen 2016-02-12 13:02:05 -08:00 committed by Ingo Molnar
parent c8df400984
commit 5c1d90f510
1 changed files with 19 additions and 3 deletions
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20
arch/x86/include/asm/pgtable_types.h
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@ -20,13 +20,18 @@
#define _PAGE_BIT_SOFTW2 10 /* " */
#define _PAGE_BIT_SOFTW3 11 /* " */
#define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */
#define _PAGE_BIT_SOFTW4 58 /* available for programmer */
#define _PAGE_BIT_PKEY_BIT0 59 /* Protection Keys, bit 1/4 */
#define _PAGE_BIT_PKEY_BIT1 60 /* Protection Keys, bit 2/4 */
#define _PAGE_BIT_PKEY_BIT2 61 /* Protection Keys, bit 3/4 */
#define _PAGE_BIT_PKEY_BIT3 62 /* Protection Keys, bit 4/4 */
#define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */
#define _PAGE_BIT_SPECIAL _PAGE_BIT_SOFTW1
#define _PAGE_BIT_CPA_TEST _PAGE_BIT_SOFTW1
#define _PAGE_BIT_HIDDEN _PAGE_BIT_SOFTW3 /* hidden by kmemcheck */
#define _PAGE_BIT_SOFT_DIRTY _PAGE_BIT_SOFTW3 /* software dirty tracking */
#define _PAGE_BIT_SOFTW4 58 /* available for programmer */
#define _PAGE_BIT_DEVMAP _PAGE_BIT_SOFTW4
#define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */
/* If _PAGE_BIT_PRESENT is clear, we use these: */
/* - if the user mapped it with PROT_NONE; pte_present gives true */
@ -47,6 +52,17 @@
#define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
#define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
#define _PAGE_CPA_TEST (_AT(pteval_t, 1) << _PAGE_BIT_CPA_TEST)
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
#define _PAGE_PKEY_BIT0 (_AT(pteval_t, 1) << _PAGE_BIT_PKEY_BIT0)
#define _PAGE_PKEY_BIT1 (_AT(pteval_t, 1) << _PAGE_BIT_PKEY_BIT1)
#define _PAGE_PKEY_BIT2 (_AT(pteval_t, 1) << _PAGE_BIT_PKEY_BIT2)
#define _PAGE_PKEY_BIT3 (_AT(pteval_t, 1) << _PAGE_BIT_PKEY_BIT3)
#else
#define _PAGE_PKEY_BIT0 (_AT(pteval_t, 0))
#define _PAGE_PKEY_BIT1 (_AT(pteval_t, 0))
#define _PAGE_PKEY_BIT2 (_AT(pteval_t, 0))
#define _PAGE_PKEY_BIT3 (_AT(pteval_t, 0))
#endif
#define __HAVE_ARCH_PTE_SPECIAL
#ifdef CONFIG_KMEMCHECK