Eric Lee / linux-smarc-t335x-v3.2

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Commit a0a8f5364a5ad248aec6cb705e0092ff563edc2f

Authored by Nick Piggin
Committed by Linus Torvalds
1 parent 2682497245
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

x86: implement pte_special 

Implement the pte_special bit for x86.  This is required to support
lockless get_user_pages, because we need to know whether or not we can
refcount a particular page given only its pte (and no vma).

[hugh@veritas.com: fix a BUG]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 6 additions and 3 deletions Side-by-side Diff

include/asm-x86/pgtable.h
Diff comments   View file @ a0a8f53
... ... @@ -18,6 +18,7 @@
18 18 #define _PAGE_BIT_UNUSED2 10
19 19 #define _PAGE_BIT_UNUSED3 11
20 20 #define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */
  21 +#define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1
21 22 #define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */
22 23  
23 24 #define _PAGE_PRESENT (_AT(pteval_t, 1) << _PAGE_BIT_PRESENT)
... ... @@ -34,6 +35,8 @@
34 35 #define _PAGE_UNUSED3 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3)
35 36 #define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
36 37 #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
  38 +#define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
  39 +#define __HAVE_ARCH_PTE_SPECIAL
37 40  
38 41 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
39 42 #define _PAGE_NX (_AT(pteval_t, 1) << _PAGE_BIT_NX)
... ... @@ -54,7 +57,7 @@
54 57  
55 58 /* Set of bits not changed in pte_modify */
56 59 #define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
57   - _PAGE_ACCESSED | _PAGE_DIRTY)
  60 + _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY)
58 61  
59 62 #define _PAGE_CACHE_MASK (_PAGE_PCD | _PAGE_PWT)
60 63 #define _PAGE_CACHE_WB (0)
... ... @@ -180,7 +183,7 @@
180 183  
181 184 static inline int pte_special(pte_t pte)
182 185 {
183   - return 0;
  186 + return pte_val(pte) & _PAGE_SPECIAL;
184 187 }
185 188  
186 189 static inline int pmd_large(pmd_t pte)
... ... @@ -246,7 +249,7 @@
246 249  
247 250 static inline pte_t pte_mkspecial(pte_t pte)
248 251 {
249   - return pte;
  252 + return __pte(pte_val(pte) | _PAGE_SPECIAL);
250 253 }
251 254  
252 255 extern pteval_t __supported_pte_mask;