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/arch/parisc/include/asm/pgalloc.h

https://github.com/aicjofs/android_kernel_lge_v500_20d
C Header | 149 lines | 102 code | 23 blank | 24 comment | 9 complexity | 7b683a6ed07d15f75b9ec2a24474ba9b MD5 | raw file
  1#ifndef _ASM_PGALLOC_H
  2#define _ASM_PGALLOC_H
  3
  4#include <linux/gfp.h>
  5#include <linux/mm.h>
  6#include <linux/threads.h>
  7#include <asm/processor.h>
  8#include <asm/fixmap.h>
  9
 10#include <asm/cache.h>
 11
 12/* Allocate the top level pgd (page directory)
 13 *
 14 * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we
 15 * allocate the first pmd adjacent to the pgd.  This means that we can
 16 * subtract a constant offset to get to it.  The pmd and pgd sizes are
 17 * arranged so that a single pmd covers 4GB (giving a full 64-bit
 18 * process access to 8TB) so our lookups are effectively L2 for the
 19 * first 4GB of the kernel (i.e. for all ILP32 processes and all the
 20 * kernel for machines with under 4GB of memory) */
 21static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 22{
 23	pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,
 24					       PGD_ALLOC_ORDER);
 25	pgd_t *actual_pgd = pgd;
 26
 27	if (likely(pgd != NULL)) {
 28		memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);
 29#ifdef CONFIG_64BIT
 30		actual_pgd += PTRS_PER_PGD;
 31		/* Populate first pmd with allocated memory.  We mark it
 32		 * with PxD_FLAG_ATTACHED as a signal to the system that this
 33		 * pmd entry may not be cleared. */
 34		__pgd_val_set(*actual_pgd, (PxD_FLAG_PRESENT | 
 35				        PxD_FLAG_VALID | 
 36					PxD_FLAG_ATTACHED) 
 37			+ (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT));
 38		/* The first pmd entry also is marked with _PAGE_GATEWAY as
 39		 * a signal that this pmd may not be freed */
 40		__pgd_val_set(*pgd, PxD_FLAG_ATTACHED);
 41#endif
 42	}
 43	return actual_pgd;
 44}
 45
 46static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 47{
 48#ifdef CONFIG_64BIT
 49	pgd -= PTRS_PER_PGD;
 50#endif
 51	free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);
 52}
 53
 54#if PT_NLEVELS == 3
 55
 56/* Three Level Page Table Support for pmd's */
 57
 58static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
 59{
 60	__pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) +
 61		        (__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT));
 62}
 63
 64static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 65{
 66	pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL|__GFP_REPEAT,
 67					       PMD_ORDER);
 68	if (pmd)
 69		memset(pmd, 0, PAGE_SIZE<<PMD_ORDER);
 70	return pmd;
 71}
 72
 73static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 74{
 75#ifdef CONFIG_64BIT
 76	if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
 77		/* This is the permanent pmd attached to the pgd;
 78		 * cannot free it */
 79		return;
 80#endif
 81	free_pages((unsigned long)pmd, PMD_ORDER);
 82}
 83
 84#else
 85
 86/* Two Level Page Table Support for pmd's */
 87
 88/*
 89 * allocating and freeing a pmd is trivial: the 1-entry pmd is
 90 * inside the pgd, so has no extra memory associated with it.
 91 */
 92
 93#define pmd_alloc_one(mm, addr)		({ BUG(); ((pmd_t *)2); })
 94#define pmd_free(mm, x)			do { } while (0)
 95#define pgd_populate(mm, pmd, pte)	BUG()
 96
 97#endif
 98
 99static inline void
100pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
101{
102#ifdef CONFIG_64BIT
103	/* preserve the gateway marker if this is the beginning of
104	 * the permanent pmd */
105	if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
106		__pmd_val_set(*pmd, (PxD_FLAG_PRESENT |
107				 PxD_FLAG_VALID |
108				 PxD_FLAG_ATTACHED) 
109			+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
110	else
111#endif
112		__pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) 
113			+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
114}
115
116#define pmd_populate(mm, pmd, pte_page) \
117	pmd_populate_kernel(mm, pmd, page_address(pte_page))
118#define pmd_pgtable(pmd) pmd_page(pmd)
119
120static inline pgtable_t
121pte_alloc_one(struct mm_struct *mm, unsigned long address)
122{
123	struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
124	if (page)
125		pgtable_page_ctor(page);
126	return page;
127}
128
129static inline pte_t *
130pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
131{
132	pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
133	return pte;
134}
135
136static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
137{
138	free_page((unsigned long)pte);
139}
140
141static inline void pte_free(struct mm_struct *mm, struct page *pte)
142{
143	pgtable_page_dtor(pte);
144	pte_free_kernel(mm, page_address(pte));
145}
146
147#define check_pgt_cache()	do { } while (0)
148
149#endif