#ifndef _ASM_PGALLOC_H #define _ASM_PGALLOC_H #include <linux/gfp.h> #include <linux/mm.h> #include <linux/threads.h> #include <asm/processor.h> #include <asm/fixmap.h> #include <asm/cache.h> /* Allocate the top level pgd (page directory) * * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we * allocate the first pmd adjacent to the pgd. This means that we can * subtract a constant offset to get to it. The pmd and pgd sizes are * arranged so that a single pmd covers 4GB (giving a full 64-bit * process access to 8TB) so our lookups are effectively L2 for the * first 4GB of the kernel (i.e. for all ILP32 processes and all the * kernel for machines with under 4GB of memory) */ static inline pgd_t *pgd_alloc(struct mm_struct *mm) { pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, PGD_ALLOC_ORDER); pgd_t *actual_pgd = pgd; if (likely(pgd != NULL)) { memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER); #ifdef CONFIG_64BIT actual_pgd += PTRS_PER_PGD; /* Populate first pmd with allocated memory. We mark it * with PxD_FLAG_ATTACHED as a signal to the system that this * pmd entry may not be cleared. */ __pgd_val_set(*actual_pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID | PxD_FLAG_ATTACHED) + (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT)); /* The first pmd entry also is marked with _PAGE_GATEWAY as * a signal that this pmd may not be freed */ __pgd_val_set(*pgd, PxD_FLAG_ATTACHED); #endif } return actual_pgd; } static inline void pgd_free(pgd_t *pgd) { #ifdef CONFIG_64BIT pgd -= PTRS_PER_PGD; #endif free_pages((unsigned long)pgd, PGD_ALLOC_ORDER); } #if PT_NLEVELS == 3 /* Three Level Page Table Support for pmd's */ static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd) { __pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) + (__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT)); } static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address) { pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL|__GFP_REPEAT, PMD_ORDER); if (pmd) memset(pmd, 0, PAGE_SIZE<<PMD_ORDER); return pmd; } static inline void pmd_free(pmd_t *pmd) { #ifdef CONFIG_64BIT if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED) /* This is the permanent pmd attached to the pgd; * cannot free it */ return; #endif free_pages((unsigned long)pmd, PMD_ORDER); } #else /* Two Level Page Table Support for pmd's */ /* * allocating and freeing a pmd is trivial: the 1-entry pmd is * inside the pgd, so has no extra memory associated with it. */ #define pmd_alloc_one(mm, addr) ({ BUG(); ((pmd_t *)2); }) #define pmd_free(x) do { } while (0) #define pgd_populate(mm, pmd, pte) BUG() #endif static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte) { #ifdef CONFIG_64BIT /* preserve the gateway marker if this is the beginning of * the permanent pmd */ if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED) __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID | PxD_FLAG_ATTACHED) + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)); else #endif __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)); } #define pmd_populate(mm, pmd, pte_page) \ pmd_populate_kernel(mm, pmd, page_address(pte_page)) static inline struct page * pte_alloc_one(struct mm_struct *mm, unsigned long address) { struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO); return page; } static inline pte_t * pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr) { pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO); return pte; } static inline void pte_free_kernel(pte_t *pte) { free_page((unsigned long)pte); } #define pte_free(page) pte_free_kernel(page_address(page)) #define check_pgt_cache() do { } while (0) #endif