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0186f47e KG |
1 | /* |
2 | * This file contains common routines for dealing with free of page tables | |
8d30c14c | 3 | * Along with common page table handling code |
0186f47e KG |
4 | * |
5 | * Derived from arch/powerpc/mm/tlb_64.c: | |
6 | * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) | |
7 | * | |
8 | * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) | |
9 | * and Cort Dougan (PReP) (cort@cs.nmt.edu) | |
10 | * Copyright (C) 1996 Paul Mackerras | |
11 | * | |
12 | * Derived from "arch/i386/mm/init.c" | |
13 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
14 | * | |
15 | * Dave Engebretsen <engebret@us.ibm.com> | |
16 | * Rework for PPC64 port. | |
17 | * | |
18 | * This program is free software; you can redistribute it and/or | |
19 | * modify it under the terms of the GNU General Public License | |
20 | * as published by the Free Software Foundation; either version | |
21 | * 2 of the License, or (at your option) any later version. | |
22 | */ | |
23 | ||
24 | #include <linux/kernel.h> | |
5a0e3ad6 | 25 | #include <linux/gfp.h> |
0186f47e | 26 | #include <linux/mm.h> |
0186f47e KG |
27 | #include <linux/percpu.h> |
28 | #include <linux/hardirq.h> | |
41151e77 | 29 | #include <linux/hugetlb.h> |
0186f47e KG |
30 | #include <asm/pgalloc.h> |
31 | #include <asm/tlbflush.h> | |
32 | #include <asm/tlb.h> | |
33 | ||
8d30c14c BH |
34 | static inline int is_exec_fault(void) |
35 | { | |
36 | return current->thread.regs && TRAP(current->thread.regs) == 0x400; | |
37 | } | |
38 | ||
39 | /* We only try to do i/d cache coherency on stuff that looks like | |
40 | * reasonably "normal" PTEs. We currently require a PTE to be present | |
30bda41a | 41 | * and we avoid _PAGE_SPECIAL and cache inhibited pte. We also only do that |
ea3cc330 | 42 | * on userspace PTEs |
8d30c14c BH |
43 | */ |
44 | static inline int pte_looks_normal(pte_t pte) | |
45 | { | |
ac29c640 | 46 | |
26973fa5 | 47 | if (pte_present(pte) && !pte_special(pte)) { |
30bda41a AK |
48 | if (pte_ci(pte)) |
49 | return 0; | |
ac29c640 AK |
50 | if (pte_user(pte)) |
51 | return 1; | |
52 | } | |
53 | return 0; | |
8d30c14c BH |
54 | } |
55 | ||
e51df2c1 | 56 | static struct page *maybe_pte_to_page(pte_t pte) |
ea3cc330 BH |
57 | { |
58 | unsigned long pfn = pte_pfn(pte); | |
59 | struct page *page; | |
60 | ||
61 | if (unlikely(!pfn_valid(pfn))) | |
62 | return NULL; | |
63 | page = pfn_to_page(pfn); | |
64 | if (PageReserved(page)) | |
65 | return NULL; | |
66 | return page; | |
67 | } | |
68 | ||
d81e6f8b | 69 | #ifdef CONFIG_PPC_BOOK3S |
ea3cc330 | 70 | |
8d30c14c | 71 | /* Server-style MMU handles coherency when hashing if HW exec permission |
ea3cc330 BH |
72 | * is supposed per page (currently 64-bit only). If not, then, we always |
73 | * flush the cache for valid PTEs in set_pte. Embedded CPU without HW exec | |
74 | * support falls into the same category. | |
8d30c14c | 75 | */ |
ea3cc330 | 76 | |
79df1b37 | 77 | static pte_t set_pte_filter(pte_t pte) |
8d30c14c | 78 | { |
4dfb88ca AK |
79 | if (radix_enabled()) |
80 | return pte; | |
81 | ||
ea3cc330 BH |
82 | pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS); |
83 | if (pte_looks_normal(pte) && !(cpu_has_feature(CPU_FTR_COHERENT_ICACHE) || | |
84 | cpu_has_feature(CPU_FTR_NOEXECUTE))) { | |
85 | struct page *pg = maybe_pte_to_page(pte); | |
86 | if (!pg) | |
87 | return pte; | |
88 | if (!test_bit(PG_arch_1, &pg->flags)) { | |
89 | flush_dcache_icache_page(pg); | |
90 | set_bit(PG_arch_1, &pg->flags); | |
91 | } | |
92 | } | |
93 | return pte; | |
8d30c14c | 94 | } |
ea3cc330 BH |
95 | |
96 | static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, | |
97 | int dirty) | |
8d30c14c | 98 | { |
ea3cc330 | 99 | return pte; |
8d30c14c | 100 | } |
ea3cc330 | 101 | |
d81e6f8b | 102 | #else /* CONFIG_PPC_BOOK3S */ |
ea3cc330 BH |
103 | |
104 | /* Embedded type MMU with HW exec support. This is a bit more complicated | |
105 | * as we don't have two bits to spare for _PAGE_EXEC and _PAGE_HWEXEC so | |
106 | * instead we "filter out" the exec permission for non clean pages. | |
8d30c14c | 107 | */ |
79df1b37 | 108 | static pte_t set_pte_filter(pte_t pte) |
8d30c14c | 109 | { |
ea3cc330 BH |
110 | struct page *pg; |
111 | ||
112 | /* No exec permission in the first place, move on */ | |
26973fa5 | 113 | if (!pte_exec(pte) || !pte_looks_normal(pte)) |
ea3cc330 BH |
114 | return pte; |
115 | ||
116 | /* If you set _PAGE_EXEC on weird pages you're on your own */ | |
117 | pg = maybe_pte_to_page(pte); | |
118 | if (unlikely(!pg)) | |
119 | return pte; | |
120 | ||
121 | /* If the page clean, we move on */ | |
122 | if (test_bit(PG_arch_1, &pg->flags)) | |
123 | return pte; | |
124 | ||
125 | /* If it's an exec fault, we flush the cache and make it clean */ | |
126 | if (is_exec_fault()) { | |
127 | flush_dcache_icache_page(pg); | |
128 | set_bit(PG_arch_1, &pg->flags); | |
129 | return pte; | |
130 | } | |
131 | ||
132 | /* Else, we filter out _PAGE_EXEC */ | |
26973fa5 | 133 | return pte_exprotect(pte); |
8d30c14c | 134 | } |
ea3cc330 BH |
135 | |
136 | static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, | |
137 | int dirty) | |
138 | { | |
139 | struct page *pg; | |
140 | ||
141 | /* So here, we only care about exec faults, as we use them | |
142 | * to recover lost _PAGE_EXEC and perform I$/D$ coherency | |
143 | * if necessary. Also if _PAGE_EXEC is already set, same deal, | |
144 | * we just bail out | |
145 | */ | |
26973fa5 | 146 | if (dirty || pte_exec(pte) || !is_exec_fault()) |
ea3cc330 BH |
147 | return pte; |
148 | ||
149 | #ifdef CONFIG_DEBUG_VM | |
150 | /* So this is an exec fault, _PAGE_EXEC is not set. If it was | |
151 | * an error we would have bailed out earlier in do_page_fault() | |
152 | * but let's make sure of it | |
153 | */ | |
154 | if (WARN_ON(!(vma->vm_flags & VM_EXEC))) | |
155 | return pte; | |
156 | #endif /* CONFIG_DEBUG_VM */ | |
157 | ||
158 | /* If you set _PAGE_EXEC on weird pages you're on your own */ | |
159 | pg = maybe_pte_to_page(pte); | |
160 | if (unlikely(!pg)) | |
161 | goto bail; | |
162 | ||
163 | /* If the page is already clean, we move on */ | |
164 | if (test_bit(PG_arch_1, &pg->flags)) | |
165 | goto bail; | |
166 | ||
167 | /* Clean the page and set PG_arch_1 */ | |
168 | flush_dcache_icache_page(pg); | |
169 | set_bit(PG_arch_1, &pg->flags); | |
170 | ||
171 | bail: | |
26973fa5 | 172 | return pte_mkexec(pte); |
ea3cc330 BH |
173 | } |
174 | ||
d81e6f8b | 175 | #endif /* CONFIG_PPC_BOOK3S */ |
8d30c14c BH |
176 | |
177 | /* | |
178 | * set_pte stores a linux PTE into the linux page table. | |
179 | */ | |
ea3cc330 BH |
180 | void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, |
181 | pte_t pte) | |
8d30c14c | 182 | { |
8a0516ed | 183 | /* |
da7ad366 AK |
184 | * Make sure hardware valid bit is not set. We don't do |
185 | * tlb flush for this update. | |
8a0516ed | 186 | */ |
dd0e144a | 187 | VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep)); |
c7d54842 | 188 | |
c618f6b1 | 189 | /* Add the pte bit when trying to set a pte */ |
26973fa5 | 190 | pte = pte_mkpte(pte); |
8a0516ed | 191 | |
8d30c14c BH |
192 | /* Note: mm->context.id might not yet have been assigned as |
193 | * this context might not have been activated yet when this | |
194 | * is called. | |
195 | */ | |
79df1b37 | 196 | pte = set_pte_filter(pte); |
8d30c14c BH |
197 | |
198 | /* Perform the setting of the PTE */ | |
199 | __set_pte_at(mm, addr, ptep, pte, 0); | |
200 | } | |
201 | ||
202 | /* | |
203 | * This is called when relaxing access to a PTE. It's also called in the page | |
204 | * fault path when we don't hit any of the major fault cases, ie, a minor | |
205 | * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have | |
206 | * handled those two for us, we additionally deal with missing execute | |
207 | * permission here on some processors | |
208 | */ | |
209 | int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address, | |
210 | pte_t *ptep, pte_t entry, int dirty) | |
211 | { | |
212 | int changed; | |
ea3cc330 | 213 | entry = set_access_flags_filter(entry, vma, dirty); |
8d30c14c BH |
214 | changed = !pte_same(*(ptep), entry); |
215 | if (changed) { | |
f069ff39 | 216 | assert_pte_locked(vma->vm_mm, address); |
e4c1112c AK |
217 | __ptep_set_access_flags(vma, ptep, entry, |
218 | address, mmu_virtual_psize); | |
8d30c14c BH |
219 | } |
220 | return changed; | |
221 | } | |
222 | ||
f069ff39 AK |
223 | #ifdef CONFIG_HUGETLB_PAGE |
224 | extern int huge_ptep_set_access_flags(struct vm_area_struct *vma, | |
225 | unsigned long addr, pte_t *ptep, | |
226 | pte_t pte, int dirty) | |
227 | { | |
228 | #ifdef HUGETLB_NEED_PRELOAD | |
229 | /* | |
230 | * The "return 1" forces a call of update_mmu_cache, which will write a | |
231 | * TLB entry. Without this, platforms that don't do a write of the TLB | |
232 | * entry in the TLB miss handler asm will fault ad infinitum. | |
233 | */ | |
234 | ptep_set_access_flags(vma, addr, ptep, pte, dirty); | |
235 | return 1; | |
236 | #else | |
e4c1112c | 237 | int changed, psize; |
f069ff39 AK |
238 | |
239 | pte = set_access_flags_filter(pte, vma, dirty); | |
240 | changed = !pte_same(*(ptep), pte); | |
241 | if (changed) { | |
e4c1112c AK |
242 | |
243 | #ifdef CONFIG_PPC_BOOK3S_64 | |
ed515b68 AK |
244 | struct hstate *h = hstate_vma(vma); |
245 | ||
246 | psize = hstate_get_psize(h); | |
247 | #ifdef CONFIG_DEBUG_VM | |
248 | assert_spin_locked(huge_pte_lockptr(h, vma->vm_mm, ptep)); | |
249 | #endif | |
250 | ||
e4c1112c AK |
251 | #else |
252 | /* | |
253 | * Not used on non book3s64 platforms. But 8xx | |
254 | * can possibly use tsize derived from hstate. | |
255 | */ | |
256 | psize = 0; | |
f069ff39 | 257 | #endif |
e4c1112c | 258 | __ptep_set_access_flags(vma, ptep, pte, addr, psize); |
f069ff39 AK |
259 | } |
260 | return changed; | |
261 | #endif | |
262 | } | |
263 | #endif /* CONFIG_HUGETLB_PAGE */ | |
264 | ||
8d30c14c BH |
265 | #ifdef CONFIG_DEBUG_VM |
266 | void assert_pte_locked(struct mm_struct *mm, unsigned long addr) | |
267 | { | |
268 | pgd_t *pgd; | |
269 | pud_t *pud; | |
270 | pmd_t *pmd; | |
271 | ||
272 | if (mm == &init_mm) | |
273 | return; | |
274 | pgd = mm->pgd + pgd_index(addr); | |
275 | BUG_ON(pgd_none(*pgd)); | |
276 | pud = pud_offset(pgd, addr); | |
277 | BUG_ON(pud_none(*pud)); | |
278 | pmd = pmd_offset(pud, addr); | |
a00e7bea AK |
279 | /* |
280 | * khugepaged to collapse normal pages to hugepage, first set | |
281 | * pmd to none to force page fault/gup to take mmap_sem. After | |
282 | * pmd is set to none, we do a pte_clear which does this assertion | |
283 | * so if we find pmd none, return. | |
284 | */ | |
285 | if (pmd_none(*pmd)) | |
286 | return; | |
8d30c14c | 287 | BUG_ON(!pmd_present(*pmd)); |
797a747a | 288 | assert_spin_locked(pte_lockptr(mm, pmd)); |
8d30c14c BH |
289 | } |
290 | #endif /* CONFIG_DEBUG_VM */ | |
291 | ||
e9ab1a1c AK |
292 | unsigned long vmalloc_to_phys(void *va) |
293 | { | |
294 | unsigned long pfn = vmalloc_to_pfn(va); | |
295 | ||
296 | BUG_ON(!pfn); | |
297 | return __pa(pfn_to_kaddr(pfn)) + offset_in_page(va); | |
298 | } | |
299 | EXPORT_SYMBOL_GPL(vmalloc_to_phys); |