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-rw-r--r--arch/x86/include/asm/pgtable.h3
-rw-r--r--arch/x86/mm/pat.c8
-rw-r--r--include/asm-generic/pgtable.h4
3 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 6968d4f6be3..579f8ceee94 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -168,6 +168,9 @@
#ifndef __ASSEMBLY__
+#define pgprot_writecombine pgprot_writecombine
+extern pgprot_t pgprot_writecombine(pgprot_t prot);
+
/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 1069ffecf77..d5254bae84f 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -832,6 +832,14 @@ void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
}
}
+pgprot_t pgprot_writecombine(pgprot_t prot)
+{
+ if (pat_enabled)
+ return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
+ else
+ return pgprot_noncached(prot);
+}
+
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
/* get Nth element of the linked list */
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index ef87f889ef6..b84633801fb 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -129,6 +129,10 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
#define move_pte(pte, prot, old_addr, new_addr) (pte)
#endif
+#ifndef pgprot_writecombine
+#define pgprot_writecombine pgprot_noncached
+#endif
+
/*
* When walking page tables, get the address of the next boundary,
* or the end address of the range if that comes earlier. Although no