diff options
Diffstat (limited to 'arch/x86/mm/init.c')
| -rw-r--r-- | arch/x86/mm/init.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 66dba36f2343..82b41d56bb98 100644 --- 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; @@ -687,3 +716,11 @@ void __init zone_sizes_init(void) free_area_init_nodes(max_zone_pfns); } +void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache) +{ + /* entry 0 MUST be WB (hardwired to speed up translations) */ + BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB); + + __cachemode2pte_tbl[cache] = __cm_idx2pte(entry); + __pte2cachemode_tbl[entry] = cache; +} |