Avoid beyond bounds copy while caching ACL
[zen-stable.git] / arch / hexagon / include / asm / pgalloc.h
blob13443c7751315e3b8e7c25e1b0f28ab8da6fa3d5
1 /*
2 * Page table support for the Hexagon architecture
4 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
21 #ifndef _ASM_PGALLOC_H
22 #define _ASM_PGALLOC_H
24 #include <asm/mem-layout.h>
25 #include <asm/atomic.h>
27 #define check_pgt_cache() do {} while (0)
29 extern unsigned long long kmap_generation;
32 * Page table creation interface
34 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
36 pgd_t *pgd;
38 pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
41 * There may be better ways to do this, but to ensure
42 * that new address spaces always contain the kernel
43 * base mapping, and to ensure that the user area is
44 * initially marked invalid, initialize the new map
45 * map with a copy of the kernel's persistent map.
48 memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t *));
49 mm->context.generation = kmap_generation;
51 /* Physical version is what is passed to virtual machine on switch */
52 mm->context.ptbase = __pa(pgd);
54 return pgd;
57 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
59 free_page((unsigned long) pgd);
62 static inline struct page *pte_alloc_one(struct mm_struct *mm,
63 unsigned long address)
65 struct page *pte;
67 pte = alloc_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
69 if (pte)
70 pgtable_page_ctor(pte);
72 return pte;
75 /* _kernel variant gets to use a different allocator */
76 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
77 unsigned long address)
79 gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
80 return (pte_t *) __get_free_page(flags);
83 static inline void pte_free(struct mm_struct *mm, struct page *pte)
85 pgtable_page_dtor(pte);
86 __free_page(pte);
89 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
91 free_page((unsigned long)pte);
94 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
95 pgtable_t pte)
98 * Conveniently, zero in 3 LSB means indirect 4K page table.
99 * Not so convenient when you're trying to vary the page size.
101 set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
102 HEXAGON_L1_PTE_SIZE));
106 * Other architectures seem to have ways of making all processes
107 * share the same pmd's for their kernel mappings, but the v0.3
108 * Hexagon VM spec has a "monolithic" L1 table for user and kernel
109 * segments. We track "generations" of the kernel map to minimize
110 * overhead, and update the "slave" copies of the kernel mappings
111 * as part of switch_mm. However, we still need to update the
112 * kernel map of the active thread who's calling pmd_populate_kernel...
114 static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
115 pte_t *pte)
117 extern spinlock_t kmap_gen_lock;
118 pmd_t *ppmd;
119 int pmdindex;
121 spin_lock(&kmap_gen_lock);
122 kmap_generation++;
123 mm->context.generation = kmap_generation;
124 current->active_mm->context.generation = kmap_generation;
125 spin_unlock(&kmap_gen_lock);
127 set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
130 * Now the "slave" copy of the current thread.
131 * This is pointer arithmetic, not byte addresses!
133 pmdindex = (pgd_t *)pmd - mm->pgd;
134 ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
135 set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
136 if (pmdindex > max_kernel_seg)
137 max_kernel_seg = pmdindex;
140 #define __pte_free_tlb(tlb, pte, addr) \
141 do { \
142 pgtable_page_dtor((pte)); \
143 tlb_remove_page((tlb), (pte)); \
144 } while (0)
146 #endif