~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/arm64/mm/pageattr.c

Version: ~ [ linux-5.9 ] ~ [ linux-5.8.14 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.70 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.150 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.200 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.238 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.238 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (c) 2014, The Linux Foundation. All rights reserved.
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License version 2 and
  6  * only version 2 as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 11  * GNU General Public License for more details.
 12  */
 13 #include <linux/kernel.h>
 14 #include <linux/mm.h>
 15 #include <linux/module.h>
 16 #include <linux/sched.h>
 17 #include <linux/vmalloc.h>
 18 
 19 #include <asm/pgtable.h>
 20 #include <asm/set_memory.h>
 21 #include <asm/tlbflush.h>
 22 
 23 struct page_change_data {
 24         pgprot_t set_mask;
 25         pgprot_t clear_mask;
 26 };
 27 
 28 static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
 29                         void *data)
 30 {
 31         struct page_change_data *cdata = data;
 32         pte_t pte = READ_ONCE(*ptep);
 33 
 34         pte = clear_pte_bit(pte, cdata->clear_mask);
 35         pte = set_pte_bit(pte, cdata->set_mask);
 36 
 37         set_pte(ptep, pte);
 38         return 0;
 39 }
 40 
 41 /*
 42  * This function assumes that the range is mapped with PAGE_SIZE pages.
 43  */
 44 static int __change_memory_common(unsigned long start, unsigned long size,
 45                                 pgprot_t set_mask, pgprot_t clear_mask)
 46 {
 47         struct page_change_data data;
 48         int ret;
 49 
 50         data.set_mask = set_mask;
 51         data.clear_mask = clear_mask;
 52 
 53         ret = apply_to_page_range(&init_mm, start, size, change_page_range,
 54                                         &data);
 55 
 56         flush_tlb_kernel_range(start, start + size);
 57         return ret;
 58 }
 59 
 60 static int change_memory_common(unsigned long addr, int numpages,
 61                                 pgprot_t set_mask, pgprot_t clear_mask)
 62 {
 63         unsigned long start = addr;
 64         unsigned long size = PAGE_SIZE*numpages;
 65         unsigned long end = start + size;
 66         struct vm_struct *area;
 67 
 68         if (!PAGE_ALIGNED(addr)) {
 69                 start &= PAGE_MASK;
 70                 end = start + size;
 71                 WARN_ON_ONCE(1);
 72         }
 73 
 74         /*
 75          * Kernel VA mappings are always live, and splitting live section
 76          * mappings into page mappings may cause TLB conflicts. This means
 77          * we have to ensure that changing the permission bits of the range
 78          * we are operating on does not result in such splitting.
 79          *
 80          * Let's restrict ourselves to mappings created by vmalloc (or vmap).
 81          * Those are guaranteed to consist entirely of page mappings, and
 82          * splitting is never needed.
 83          *
 84          * So check whether the [addr, addr + size) interval is entirely
 85          * covered by precisely one VM area that has the VM_ALLOC flag set.
 86          */
 87         area = find_vm_area((void *)addr);
 88         if (!area ||
 89             end > (unsigned long)area->addr + area->size ||
 90             !(area->flags & VM_ALLOC))
 91                 return -EINVAL;
 92 
 93         if (!numpages)
 94                 return 0;
 95 
 96         return __change_memory_common(start, size, set_mask, clear_mask);
 97 }
 98 
 99 int set_memory_ro(unsigned long addr, int numpages)
100 {
101         return change_memory_common(addr, numpages,
102                                         __pgprot(PTE_RDONLY),
103                                         __pgprot(PTE_WRITE));
104 }
105 
106 int set_memory_rw(unsigned long addr, int numpages)
107 {
108         return change_memory_common(addr, numpages,
109                                         __pgprot(PTE_WRITE),
110                                         __pgprot(PTE_RDONLY));
111 }
112 
113 int set_memory_nx(unsigned long addr, int numpages)
114 {
115         return change_memory_common(addr, numpages,
116                                         __pgprot(PTE_PXN),
117                                         __pgprot(0));
118 }
119 EXPORT_SYMBOL_GPL(set_memory_nx);
120 
121 int set_memory_x(unsigned long addr, int numpages)
122 {
123         return change_memory_common(addr, numpages,
124                                         __pgprot(0),
125                                         __pgprot(PTE_PXN));
126 }
127 EXPORT_SYMBOL_GPL(set_memory_x);
128 
129 int set_memory_valid(unsigned long addr, int numpages, int enable)
130 {
131         if (enable)
132                 return __change_memory_common(addr, PAGE_SIZE * numpages,
133                                         __pgprot(PTE_VALID),
134                                         __pgprot(0));
135         else
136                 return __change_memory_common(addr, PAGE_SIZE * numpages,
137                                         __pgprot(0),
138                                         __pgprot(PTE_VALID));
139 }
140 
141 #ifdef CONFIG_DEBUG_PAGEALLOC
142 void __kernel_map_pages(struct page *page, int numpages, int enable)
143 {
144         set_memory_valid((unsigned long)page_address(page), numpages, enable);
145 }
146 #ifdef CONFIG_HIBERNATION
147 /*
148  * When built with CONFIG_DEBUG_PAGEALLOC and CONFIG_HIBERNATION, this function
149  * is used to determine if a linear map page has been marked as not-valid by
150  * CONFIG_DEBUG_PAGEALLOC. Walk the page table and check the PTE_VALID bit.
151  * This is based on kern_addr_valid(), which almost does what we need.
152  *
153  * Because this is only called on the kernel linear map,  p?d_sect() implies
154  * p?d_present(). When debug_pagealloc is enabled, sections mappings are
155  * disabled.
156  */
157 bool kernel_page_present(struct page *page)
158 {
159         pgd_t *pgdp;
160         pud_t *pudp, pud;
161         pmd_t *pmdp, pmd;
162         pte_t *ptep;
163         unsigned long addr = (unsigned long)page_address(page);
164 
165         pgdp = pgd_offset_k(addr);
166         if (pgd_none(READ_ONCE(*pgdp)))
167                 return false;
168 
169         pudp = pud_offset(pgdp, addr);
170         pud = READ_ONCE(*pudp);
171         if (pud_none(pud))
172                 return false;
173         if (pud_sect(pud))
174                 return true;
175 
176         pmdp = pmd_offset(pudp, addr);
177         pmd = READ_ONCE(*pmdp);
178         if (pmd_none(pmd))
179                 return false;
180         if (pmd_sect(pmd))
181                 return true;
182 
183         ptep = pte_offset_kernel(pmdp, addr);
184         return pte_valid(READ_ONCE(*ptep));
185 }
186 #endif /* CONFIG_HIBERNATION */
187 #endif /* CONFIG_DEBUG_PAGEALLOC */
188 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp