diff options
| author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-03-25 03:53:42 -0300 |
|---|---|---|
| committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-03-25 03:53:42 -0300 |
| commit | 03dd4cb26d967f9588437b0fc9cc0e8353322bb7 (patch) | |
| tree | fa581f6dc1c0596391690d1f67eceef3af8246dc /arch/arc/include/asm/pgtable.h | |
| parent | d4e493caf788ef44982e131ff9c786546904d934 (diff) | |
Linux-libre 4.5-gnu
Diffstat (limited to 'arch/arc/include/asm/pgtable.h')
| -rw-r--r-- | arch/arc/include/asm/pgtable.h | 45 |
1 files changed, 26 insertions, 19 deletions
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index 57af2f05a..d426d4215 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -179,37 +179,44 @@ #define __S111 PAGE_U_X_W_R /**************************************************************** - * Page Table Lookup split + * 2 tier (PGD:PTE) software page walker * - * We implement 2 tier paging and since this is all software, we are free - * to customize the span of a PGD / PTE entry to suit us - * - * 32 bit virtual address + * [31] 32 bit virtual address [0] * ------------------------------------------------------- - * | BITS_FOR_PGD | BITS_FOR_PTE | BITS_IN_PAGE | + * | | <------------ PGDIR_SHIFT ----------> | + * | | | + * | BITS_FOR_PGD | BITS_FOR_PTE | <-- PAGE_SHIFT --> | * ------------------------------------------------------- * | | | * | | --> off in page frame - * | | * | ---> index into Page Table - * | * ----> index into Page Directory + * + * In a single page size configuration, only PAGE_SHIFT is fixed + * So both PGD and PTE sizing can be tweaked + * e.g. 8K page (PAGE_SHIFT 13) can have + * - PGDIR_SHIFT 21 -> 11:8:13 address split + * - PGDIR_SHIFT 24 -> 8:11:13 address split + * + * If Super Page is configured, PGDIR_SHIFT becomes fixed too, + * so the sizing flexibility is gone. */ -#define BITS_IN_PAGE PAGE_SHIFT - -/* Optimal Sizing of Pg Tbl - based on MMU page size */ -#if defined(CONFIG_ARC_PAGE_SIZE_8K) -#define BITS_FOR_PTE 8 /* 11:8:13 */ -#elif defined(CONFIG_ARC_PAGE_SIZE_16K) -#define BITS_FOR_PTE 8 /* 10:8:14 */ -#elif defined(CONFIG_ARC_PAGE_SIZE_4K) -#define BITS_FOR_PTE 9 /* 11:9:12 */ +#if defined(CONFIG_ARC_HUGEPAGE_16M) +#define PGDIR_SHIFT 24 +#elif defined(CONFIG_ARC_HUGEPAGE_2M) +#define PGDIR_SHIFT 21 +#else +/* + * Only Normal page support so "hackable" (see comment above) + * Default value provides 11:8:13 (8K), 11:9:12 (4K) + */ +#define PGDIR_SHIFT 21 #endif -#define BITS_FOR_PGD (32 - BITS_FOR_PTE - BITS_IN_PAGE) +#define BITS_FOR_PTE (PGDIR_SHIFT - PAGE_SHIFT) +#define BITS_FOR_PGD (32 - PGDIR_SHIFT) -#define PGDIR_SHIFT (32 - BITS_FOR_PGD) #define PGDIR_SIZE (1UL << PGDIR_SHIFT) /* vaddr span, not PDG sz */ #define PGDIR_MASK (~(PGDIR_SIZE-1)) |