x86: Make page cache mode a real type

[cascardo/linux.git] / arch / x86 / mm / init.c

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 66dba36..a9776ba 100644 (file)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -27,6 +27,35 @@
 
 #include "mm_internal.h"
 
+/*
+ * Tables translating between page_cache_type_t and pte encoding.
+ * Minimal supported modes are defined statically, modified if more supported
+ * cache modes are available.
+ * Index into __cachemode2pte_tbl is the cachemode.
+ * Index into __pte2cachemode_tbl are the caching attribute bits of the pte
+ * (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2.
+ */
+uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
+       [_PAGE_CACHE_MODE_WB]           = 0,
+       [_PAGE_CACHE_MODE_WC]           = _PAGE_PWT,
+       [_PAGE_CACHE_MODE_UC_MINUS]     = _PAGE_PCD,
+       [_PAGE_CACHE_MODE_UC]           = _PAGE_PCD | _PAGE_PWT,
+       [_PAGE_CACHE_MODE_WT]           = _PAGE_PCD,
+       [_PAGE_CACHE_MODE_WP]           = _PAGE_PCD,
+};
+EXPORT_SYMBOL_GPL(__cachemode2pte_tbl);
+uint8_t __pte2cachemode_tbl[8] = {
+       [__pte2cm_idx(0)] = _PAGE_CACHE_MODE_WB,
+       [__pte2cm_idx(_PAGE_PWT)] = _PAGE_CACHE_MODE_WC,
+       [__pte2cm_idx(_PAGE_PCD)] = _PAGE_CACHE_MODE_UC_MINUS,
+       [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD)] = _PAGE_CACHE_MODE_UC,
+       [__pte2cm_idx(_PAGE_PAT)] = _PAGE_CACHE_MODE_WB,
+       [__pte2cm_idx(_PAGE_PWT | _PAGE_PAT)] = _PAGE_CACHE_MODE_WC,
+       [__pte2cm_idx(_PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
+       [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,
+};
+EXPORT_SYMBOL_GPL(__pte2cachemode_tbl);
+
 static unsigned long __initdata pgt_buf_start;
 static unsigned long __initdata pgt_buf_end;
 static unsigned long __initdata pgt_buf_top;