[v12,7/10] x86, mm, pat: Add pgprot_writethrough() for WT

Commit Message

Toshi Kani June 1, 2015, 7:36 p.m. UTC

This patch adds pgprot_writethrough() for setting WT to a given
pgprot_t.

Signed-off-by: Toshi Kani <[e-mail]>
Reviewed-by: Konrad Rzeszutek Wilk <[e-mail]>
Reviewed-by: Thomas Gleixner <[e-mail]>
---
 arch/x86/include/asm/pgtable_types.h |    3 +++
 arch/x86/mm/pat.c                    |    7 +++++++
 include/asm-generic/pgtable.h        |    4 ++++
 3 files changed, 14 insertions(+)

Patch

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 78f0c8c..13f310b 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -367,6 +367,9 @@  extern int nx_enabled;
 #define pgprot_writecombine	pgprot_writecombine
 extern pgprot_t pgprot_writecombine(pgprot_t prot);
 
+#define pgprot_writethrough	pgprot_writethrough
+extern pgprot_t pgprot_writethrough(pgprot_t prot);
+
 /* Indicate that x86 has its own track and untrack pfn vma functions */
 #define __HAVE_PFNMAP_TRACKING
 
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 56c8b4d..a89bcde 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -999,6 +999,13 @@  pgprot_t pgprot_writecombine(pgprot_t prot)
 }
 EXPORT_SYMBOL_GPL(pgprot_writecombine);
 
+pgprot_t pgprot_writethrough(pgprot_t prot)
+{
+	return __pgprot(pgprot_val(prot) |
+				cachemode2protval(_PAGE_CACHE_MODE_WT));
+}
+EXPORT_SYMBOL_GPL(pgprot_writethrough);
+
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
 
 static struct memtype *memtype_get_idx(loff_t pos)
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 39f1d6a..bd910ce 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -262,6 +262,10 @@  static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 #define pgprot_writecombine pgprot_noncached
 #endif
 
+#ifndef pgprot_writethrough
+#define pgprot_writethrough pgprot_noncached
+#endif
+
 #ifndef pgprot_device
 #define pgprot_device pgprot_noncached
 #endif