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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * This file contains common routines for dealing with free of page tables
4 * Along with common page table handling code
5 *
6 * Derived from arch/powerpc/mm/tlb_64.c:
7 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
8 *
9 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
10 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
11 * Copyright (C) 1996 Paul Mackerras
12 *
13 * Derived from "arch/i386/mm/init.c"
14 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
15 *
16 * Dave Engebretsen <engebret@us.ibm.com>
17 * Rework for PPC64 port.
18 */
19
20#include <linux/kernel.h>
21#include <linux/gfp.h>
22#include <linux/mm.h>
23#include <linux/percpu.h>
24#include <linux/hardirq.h>
25#include <linux/hugetlb.h>
26#include <asm/pgalloc.h>
27#include <asm/tlbflush.h>
28#include <asm/tlb.h>
29#include <asm/hugetlb.h>
30
31static inline int is_exec_fault(void)
32{
33 return current->thread.regs && TRAP(current->thread.regs) == 0x400;
34}
35
36/* We only try to do i/d cache coherency on stuff that looks like
37 * reasonably "normal" PTEs. We currently require a PTE to be present
38 * and we avoid _PAGE_SPECIAL and cache inhibited pte. We also only do that
39 * on userspace PTEs
40 */
41static inline int pte_looks_normal(pte_t pte)
42{
43
44 if (pte_present(pte) && !pte_special(pte)) {
45 if (pte_ci(pte))
46 return 0;
47 if (pte_user(pte))
48 return 1;
49 }
50 return 0;
51}
52
53static struct page *maybe_pte_to_page(pte_t pte)
54{
55 unsigned long pfn = pte_pfn(pte);
56 struct page *page;
57
58 if (unlikely(!pfn_valid(pfn)))
59 return NULL;
60 page = pfn_to_page(pfn);
61 if (PageReserved(page))
62 return NULL;
63 return page;
64}
65
66#ifdef CONFIG_PPC_BOOK3S
67
68/* Server-style MMU handles coherency when hashing if HW exec permission
69 * is supposed per page (currently 64-bit only). If not, then, we always
70 * flush the cache for valid PTEs in set_pte. Embedded CPU without HW exec
71 * support falls into the same category.
72 */
73
74static pte_t set_pte_filter_hash(pte_t pte)
75{
76 if (radix_enabled())
77 return pte;
78
79 pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
80 if (pte_looks_normal(pte) && !(cpu_has_feature(CPU_FTR_COHERENT_ICACHE) ||
81 cpu_has_feature(CPU_FTR_NOEXECUTE))) {
82 struct page *pg = maybe_pte_to_page(pte);
83 if (!pg)
84 return pte;
85 if (!test_bit(PG_arch_1, &pg->flags)) {
86 flush_dcache_icache_page(pg);
87 set_bit(PG_arch_1, &pg->flags);
88 }
89 }
90 return pte;
91}
92
93#else /* CONFIG_PPC_BOOK3S */
94
95static pte_t set_pte_filter_hash(pte_t pte) { return pte; }
96
97#endif /* CONFIG_PPC_BOOK3S */
98
99/* Embedded type MMU with HW exec support. This is a bit more complicated
100 * as we don't have two bits to spare for _PAGE_EXEC and _PAGE_HWEXEC so
101 * instead we "filter out" the exec permission for non clean pages.
102 */
103static pte_t set_pte_filter(pte_t pte)
104{
105 struct page *pg;
106
107 if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
108 return set_pte_filter_hash(pte);
109
110 /* No exec permission in the first place, move on */
111 if (!pte_exec(pte) || !pte_looks_normal(pte))
112 return pte;
113
114 /* If you set _PAGE_EXEC on weird pages you're on your own */
115 pg = maybe_pte_to_page(pte);
116 if (unlikely(!pg))
117 return pte;
118
119 /* If the page clean, we move on */
120 if (test_bit(PG_arch_1, &pg->flags))
121 return pte;
122
123 /* If it's an exec fault, we flush the cache and make it clean */
124 if (is_exec_fault()) {
125 flush_dcache_icache_page(pg);
126 set_bit(PG_arch_1, &pg->flags);
127 return pte;
128 }
129
130 /* Else, we filter out _PAGE_EXEC */
131 return pte_exprotect(pte);
132}
133
134static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
135 int dirty)
136{
137 struct page *pg;
138
139 if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
140 return pte;
141
142 /* So here, we only care about exec faults, as we use them
143 * to recover lost _PAGE_EXEC and perform I$/D$ coherency
144 * if necessary. Also if _PAGE_EXEC is already set, same deal,
145 * we just bail out
146 */
147 if (dirty || pte_exec(pte) || !is_exec_fault())
148 return pte;
149
150#ifdef CONFIG_DEBUG_VM
151 /* So this is an exec fault, _PAGE_EXEC is not set. If it was
152 * an error we would have bailed out earlier in do_page_fault()
153 * but let's make sure of it
154 */
155 if (WARN_ON(!(vma->vm_flags & VM_EXEC)))
156 return pte;
157#endif /* CONFIG_DEBUG_VM */
158
159 /* If you set _PAGE_EXEC on weird pages you're on your own */
160 pg = maybe_pte_to_page(pte);
161 if (unlikely(!pg))
162 goto bail;
163
164 /* If the page is already clean, we move on */
165 if (test_bit(PG_arch_1, &pg->flags))
166 goto bail;
167
168 /* Clean the page and set PG_arch_1 */
169 flush_dcache_icache_page(pg);
170 set_bit(PG_arch_1, &pg->flags);
171
172 bail:
173 return pte_mkexec(pte);
174}
175
176/*
177 * set_pte stores a linux PTE into the linux page table.
178 */
179void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
180 pte_t pte)
181{
182 /*
183 * Make sure hardware valid bit is not set. We don't do
184 * tlb flush for this update.
185 */
186 VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
187
188 /* Add the pte bit when trying to set a pte */
189 pte = pte_mkpte(pte);
190
191 /* Note: mm->context.id might not yet have been assigned as
192 * this context might not have been activated yet when this
193 * is called.
194 */
195 pte = set_pte_filter(pte);
196
197 /* Perform the setting of the PTE */
198 __set_pte_at(mm, addr, ptep, pte, 0);
199}
200
201/*
202 * This is called when relaxing access to a PTE. It's also called in the page
203 * fault path when we don't hit any of the major fault cases, ie, a minor
204 * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have
205 * handled those two for us, we additionally deal with missing execute
206 * permission here on some processors
207 */
208int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
209 pte_t *ptep, pte_t entry, int dirty)
210{
211 int changed;
212 entry = set_access_flags_filter(entry, vma, dirty);
213 changed = !pte_same(*(ptep), entry);
214 if (changed) {
215 assert_pte_locked(vma->vm_mm, address);
216 __ptep_set_access_flags(vma, ptep, entry,
217 address, mmu_virtual_psize);
218 }
219 return changed;
220}
221
222#ifdef CONFIG_HUGETLB_PAGE
223int huge_ptep_set_access_flags(struct vm_area_struct *vma,
224 unsigned long addr, pte_t *ptep,
225 pte_t pte, int dirty)
226{
227#ifdef HUGETLB_NEED_PRELOAD
228 /*
229 * The "return 1" forces a call of update_mmu_cache, which will write a
230 * TLB entry. Without this, platforms that don't do a write of the TLB
231 * entry in the TLB miss handler asm will fault ad infinitum.
232 */
233 ptep_set_access_flags(vma, addr, ptep, pte, dirty);
234 return 1;
235#else
236 int changed, psize;
237
238 pte = set_access_flags_filter(pte, vma, dirty);
239 changed = !pte_same(*(ptep), pte);
240 if (changed) {
241
242#ifdef CONFIG_PPC_BOOK3S_64
243 struct hstate *h = hstate_vma(vma);
244
245 psize = hstate_get_psize(h);
246#ifdef CONFIG_DEBUG_VM
247 assert_spin_locked(huge_pte_lockptr(h, vma->vm_mm, ptep));
248#endif
249
250#else
251 /*
252 * Not used on non book3s64 platforms. But 8xx
253 * can possibly use tsize derived from hstate.
254 */
255 psize = 0;
256#endif
257 __ptep_set_access_flags(vma, ptep, pte, addr, psize);
258 }
259 return changed;
260#endif
261}
262#endif /* CONFIG_HUGETLB_PAGE */
263
264#ifdef CONFIG_DEBUG_VM
265void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
266{
267 pgd_t *pgd;
268 pud_t *pud;
269 pmd_t *pmd;
270
271 if (mm == &init_mm)
272 return;
273 pgd = mm->pgd + pgd_index(addr);
274 BUG_ON(pgd_none(*pgd));
275 pud = pud_offset(pgd, addr);
276 BUG_ON(pud_none(*pud));
277 pmd = pmd_offset(pud, addr);
278 /*
279 * khugepaged to collapse normal pages to hugepage, first set
280 * pmd to none to force page fault/gup to take mmap_sem. After
281 * pmd is set to none, we do a pte_clear which does this assertion
282 * so if we find pmd none, return.
283 */
284 if (pmd_none(*pmd))
285 return;
286 BUG_ON(!pmd_present(*pmd));
287 assert_spin_locked(pte_lockptr(mm, pmd));
288}
289#endif /* CONFIG_DEBUG_VM */
290
291unsigned long vmalloc_to_phys(void *va)
292{
293 unsigned long pfn = vmalloc_to_pfn(va);
294
295 BUG_ON(!pfn);
296 return __pa(pfn_to_kaddr(pfn)) + offset_in_page(va);
297}
298EXPORT_SYMBOL_GPL(vmalloc_to_phys);
299
300/*
301 * We have 4 cases for pgds and pmds:
302 * (1) invalid (all zeroes)
303 * (2) pointer to next table, as normal; bottom 6 bits == 0
304 * (3) leaf pte for huge page _PAGE_PTE set
305 * (4) hugepd pointer, _PAGE_PTE = 0 and bits [2..6] indicate size of table
306 *
307 * So long as we atomically load page table pointers we are safe against teardown,
308 * we can follow the address down to the the page and take a ref on it.
309 * This function need to be called with interrupts disabled. We use this variant
310 * when we have MSR[EE] = 0 but the paca->irq_soft_mask = IRQS_ENABLED
311 */
312pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
313 bool *is_thp, unsigned *hpage_shift)
314{
315 pgd_t pgd, *pgdp;
316 pud_t pud, *pudp;
317 pmd_t pmd, *pmdp;
318 pte_t *ret_pte;
319 hugepd_t *hpdp = NULL;
320 unsigned pdshift = PGDIR_SHIFT;
321
322 if (hpage_shift)
323 *hpage_shift = 0;
324
325 if (is_thp)
326 *is_thp = false;
327
328 pgdp = pgdir + pgd_index(ea);
329 pgd = READ_ONCE(*pgdp);
330 /*
331 * Always operate on the local stack value. This make sure the
332 * value don't get updated by a parallel THP split/collapse,
333 * page fault or a page unmap. The return pte_t * is still not
334 * stable. So should be checked there for above conditions.
335 */
336 if (pgd_none(pgd))
337 return NULL;
338
339 if (pgd_is_leaf(pgd)) {
340 ret_pte = (pte_t *)pgdp;
341 goto out;
342 }
343
344 if (is_hugepd(__hugepd(pgd_val(pgd)))) {
345 hpdp = (hugepd_t *)&pgd;
346 goto out_huge;
347 }
348
349 /*
350 * Even if we end up with an unmap, the pgtable will not
351 * be freed, because we do an rcu free and here we are
352 * irq disabled
353 */
354 pdshift = PUD_SHIFT;
355 pudp = pud_offset(&pgd, ea);
356 pud = READ_ONCE(*pudp);
357
358 if (pud_none(pud))
359 return NULL;
360
361 if (pud_is_leaf(pud)) {
362 ret_pte = (pte_t *)pudp;
363 goto out;
364 }
365
366 if (is_hugepd(__hugepd(pud_val(pud)))) {
367 hpdp = (hugepd_t *)&pud;
368 goto out_huge;
369 }
370
371 pdshift = PMD_SHIFT;
372 pmdp = pmd_offset(&pud, ea);
373 pmd = READ_ONCE(*pmdp);
374
375 /*
376 * A hugepage collapse is captured by this condition, see
377 * pmdp_collapse_flush.
378 */
379 if (pmd_none(pmd))
380 return NULL;
381
382#ifdef CONFIG_PPC_BOOK3S_64
383 /*
384 * A hugepage split is captured by this condition, see
385 * pmdp_invalidate.
386 *
387 * Huge page modification can be caught here too.
388 */
389 if (pmd_is_serializing(pmd))
390 return NULL;
391#endif
392
393 if (pmd_trans_huge(pmd) || pmd_devmap(pmd)) {
394 if (is_thp)
395 *is_thp = true;
396 ret_pte = (pte_t *)pmdp;
397 goto out;
398 }
399
400 if (pmd_is_leaf(pmd)) {
401 ret_pte = (pte_t *)pmdp;
402 goto out;
403 }
404
405 if (is_hugepd(__hugepd(pmd_val(pmd)))) {
406 hpdp = (hugepd_t *)&pmd;
407 goto out_huge;
408 }
409
410 return pte_offset_kernel(&pmd, ea);
411
412out_huge:
413 if (!hpdp)
414 return NULL;
415
416 ret_pte = hugepte_offset(*hpdp, ea, pdshift);
417 pdshift = hugepd_shift(*hpdp);
418out:
419 if (hpage_shift)
420 *hpage_shift = pdshift;
421 return ret_pte;
422}
423EXPORT_SYMBOL_GPL(__find_linux_pte);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * This file contains common routines for dealing with free of page tables
4 * Along with common page table handling code
5 *
6 * Derived from arch/powerpc/mm/tlb_64.c:
7 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
8 *
9 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
10 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
11 * Copyright (C) 1996 Paul Mackerras
12 *
13 * Derived from "arch/i386/mm/init.c"
14 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
15 *
16 * Dave Engebretsen <engebret@us.ibm.com>
17 * Rework for PPC64 port.
18 */
19
20#include <linux/kernel.h>
21#include <linux/gfp.h>
22#include <linux/mm.h>
23#include <linux/percpu.h>
24#include <linux/hardirq.h>
25#include <linux/hugetlb.h>
26#include <asm/tlbflush.h>
27#include <asm/tlb.h>
28#include <asm/hugetlb.h>
29#include <asm/pte-walk.h>
30
31#ifdef CONFIG_PPC64
32#define PGD_ALIGN (sizeof(pgd_t) * MAX_PTRS_PER_PGD)
33#else
34#define PGD_ALIGN PAGE_SIZE
35#endif
36
37pgd_t swapper_pg_dir[MAX_PTRS_PER_PGD] __section(".bss..page_aligned") __aligned(PGD_ALIGN);
38
39static inline int is_exec_fault(void)
40{
41 return current->thread.regs && TRAP(current->thread.regs) == 0x400;
42}
43
44/* We only try to do i/d cache coherency on stuff that looks like
45 * reasonably "normal" PTEs. We currently require a PTE to be present
46 * and we avoid _PAGE_SPECIAL and cache inhibited pte. We also only do that
47 * on userspace PTEs
48 */
49static inline int pte_looks_normal(pte_t pte, unsigned long addr)
50{
51
52 if (pte_present(pte) && !pte_special(pte)) {
53 if (pte_ci(pte))
54 return 0;
55 if (!is_kernel_addr(addr))
56 return 1;
57 }
58 return 0;
59}
60
61static struct folio *maybe_pte_to_folio(pte_t pte)
62{
63 unsigned long pfn = pte_pfn(pte);
64 struct page *page;
65
66 if (unlikely(!pfn_valid(pfn)))
67 return NULL;
68 page = pfn_to_page(pfn);
69 if (PageReserved(page))
70 return NULL;
71 return page_folio(page);
72}
73
74#ifdef CONFIG_PPC_BOOK3S
75
76/* Server-style MMU handles coherency when hashing if HW exec permission
77 * is supposed per page (currently 64-bit only). If not, then, we always
78 * flush the cache for valid PTEs in set_pte. Embedded CPU without HW exec
79 * support falls into the same category.
80 */
81
82static pte_t set_pte_filter_hash(pte_t pte, unsigned long addr)
83{
84 pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
85 if (pte_looks_normal(pte, addr) && !(cpu_has_feature(CPU_FTR_COHERENT_ICACHE) ||
86 cpu_has_feature(CPU_FTR_NOEXECUTE))) {
87 struct folio *folio = maybe_pte_to_folio(pte);
88 if (!folio)
89 return pte;
90 if (!test_bit(PG_dcache_clean, &folio->flags)) {
91 flush_dcache_icache_folio(folio);
92 set_bit(PG_dcache_clean, &folio->flags);
93 }
94 }
95 return pte;
96}
97
98#else /* CONFIG_PPC_BOOK3S */
99
100static pte_t set_pte_filter_hash(pte_t pte, unsigned long addr) { return pte; }
101
102#endif /* CONFIG_PPC_BOOK3S */
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.
107 *
108 * This is also called once for the folio. So only work with folio->flags here.
109 */
110static inline pte_t set_pte_filter(pte_t pte, unsigned long addr)
111{
112 struct folio *folio;
113
114 if (radix_enabled())
115 return pte;
116
117 if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
118 return set_pte_filter_hash(pte, addr);
119
120 /* No exec permission in the first place, move on */
121 if (!pte_exec(pte) || !pte_looks_normal(pte, addr))
122 return pte;
123
124 /* If you set _PAGE_EXEC on weird pages you're on your own */
125 folio = maybe_pte_to_folio(pte);
126 if (unlikely(!folio))
127 return pte;
128
129 /* If the page clean, we move on */
130 if (test_bit(PG_dcache_clean, &folio->flags))
131 return pte;
132
133 /* If it's an exec fault, we flush the cache and make it clean */
134 if (is_exec_fault()) {
135 flush_dcache_icache_folio(folio);
136 set_bit(PG_dcache_clean, &folio->flags);
137 return pte;
138 }
139
140 /* Else, we filter out _PAGE_EXEC */
141 return pte_exprotect(pte);
142}
143
144static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
145 int dirty)
146{
147 struct folio *folio;
148
149 if (IS_ENABLED(CONFIG_PPC_BOOK3S_64))
150 return pte;
151
152 if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
153 return pte;
154
155 /* So here, we only care about exec faults, as we use them
156 * to recover lost _PAGE_EXEC and perform I$/D$ coherency
157 * if necessary. Also if _PAGE_EXEC is already set, same deal,
158 * we just bail out
159 */
160 if (dirty || pte_exec(pte) || !is_exec_fault())
161 return pte;
162
163#ifdef CONFIG_DEBUG_VM
164 /* So this is an exec fault, _PAGE_EXEC is not set. If it was
165 * an error we would have bailed out earlier in do_page_fault()
166 * but let's make sure of it
167 */
168 if (WARN_ON(!(vma->vm_flags & VM_EXEC)))
169 return pte;
170#endif /* CONFIG_DEBUG_VM */
171
172 /* If you set _PAGE_EXEC on weird pages you're on your own */
173 folio = maybe_pte_to_folio(pte);
174 if (unlikely(!folio))
175 goto bail;
176
177 /* If the page is already clean, we move on */
178 if (test_bit(PG_dcache_clean, &folio->flags))
179 goto bail;
180
181 /* Clean the page and set PG_dcache_clean */
182 flush_dcache_icache_folio(folio);
183 set_bit(PG_dcache_clean, &folio->flags);
184
185 bail:
186 return pte_mkexec(pte);
187}
188
189/*
190 * set_pte stores a linux PTE into the linux page table.
191 */
192void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
193 pte_t pte, unsigned int nr)
194{
195
196 /* Note: mm->context.id might not yet have been assigned as
197 * this context might not have been activated yet when this
198 * is called. Filter the pte value and use the filtered value
199 * to setup all the ptes in the range.
200 */
201 pte = set_pte_filter(pte, addr);
202
203 /*
204 * We don't need to call arch_enter/leave_lazy_mmu_mode()
205 * because we expect set_ptes to be only be used on not present
206 * and not hw_valid ptes. Hence there is no translation cache flush
207 * involved that need to be batched.
208 */
209 for (;;) {
210
211 /*
212 * Make sure hardware valid bit is not set. We don't do
213 * tlb flush for this update.
214 */
215 VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
216
217 /* Perform the setting of the PTE */
218 __set_pte_at(mm, addr, ptep, pte, 0);
219 if (--nr == 0)
220 break;
221 ptep++;
222 addr += PAGE_SIZE;
223 pte = pte_next_pfn(pte);
224 }
225}
226
227void unmap_kernel_page(unsigned long va)
228{
229 pmd_t *pmdp = pmd_off_k(va);
230 pte_t *ptep = pte_offset_kernel(pmdp, va);
231
232 pte_clear(&init_mm, va, ptep);
233 flush_tlb_kernel_range(va, va + PAGE_SIZE);
234}
235
236/*
237 * This is called when relaxing access to a PTE. It's also called in the page
238 * fault path when we don't hit any of the major fault cases, ie, a minor
239 * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have
240 * handled those two for us, we additionally deal with missing execute
241 * permission here on some processors
242 */
243int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
244 pte_t *ptep, pte_t entry, int dirty)
245{
246 int changed;
247 entry = set_access_flags_filter(entry, vma, dirty);
248 changed = !pte_same(*(ptep), entry);
249 if (changed) {
250 assert_pte_locked(vma->vm_mm, address);
251 __ptep_set_access_flags(vma, ptep, entry,
252 address, mmu_virtual_psize);
253 }
254 return changed;
255}
256
257#ifdef CONFIG_HUGETLB_PAGE
258int huge_ptep_set_access_flags(struct vm_area_struct *vma,
259 unsigned long addr, pte_t *ptep,
260 pte_t pte, int dirty)
261{
262#ifdef HUGETLB_NEED_PRELOAD
263 /*
264 * The "return 1" forces a call of update_mmu_cache, which will write a
265 * TLB entry. Without this, platforms that don't do a write of the TLB
266 * entry in the TLB miss handler asm will fault ad infinitum.
267 */
268 ptep_set_access_flags(vma, addr, ptep, pte, dirty);
269 return 1;
270#else
271 int changed, psize;
272
273 pte = set_access_flags_filter(pte, vma, dirty);
274 changed = !pte_same(*(ptep), pte);
275 if (changed) {
276
277#ifdef CONFIG_PPC_BOOK3S_64
278 struct hstate *h = hstate_vma(vma);
279
280 psize = hstate_get_psize(h);
281#ifdef CONFIG_DEBUG_VM
282 assert_spin_locked(huge_pte_lockptr(h, vma->vm_mm, ptep));
283#endif
284
285#else
286 /*
287 * Not used on non book3s64 platforms.
288 * 8xx compares it with mmu_virtual_psize to
289 * know if it is a huge page or not.
290 */
291 psize = MMU_PAGE_COUNT;
292#endif
293 __ptep_set_access_flags(vma, ptep, pte, addr, psize);
294 }
295 return changed;
296#endif
297}
298
299#if defined(CONFIG_PPC_8xx)
300
301#if defined(CONFIG_SPLIT_PTE_PTLOCKS) || defined(CONFIG_SPLIT_PMD_PTLOCKS)
302/* We need the same lock to protect the PMD table and the two PTE tables. */
303#error "8M hugetlb folios are incompatible with split page table locks"
304#endif
305
306static void __set_huge_pte_at(pmd_t *pmd, pte_t *ptep, pte_basic_t val)
307{
308 pte_basic_t *entry = (pte_basic_t *)ptep;
309 int num, i;
310
311 /*
312 * Make sure hardware valid bit is not set. We don't do
313 * tlb flush for this update.
314 */
315 VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
316
317 num = number_of_cells_per_pte(pmd, val, 1);
318
319 for (i = 0; i < num; i++, entry++, val += SZ_4K)
320 *entry = val;
321}
322
323void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
324 pte_t pte, unsigned long sz)
325{
326 pmd_t *pmdp = pmd_off(mm, addr);
327
328 pte = set_pte_filter(pte, addr);
329
330 if (sz == SZ_8M) { /* Flag both PMD entries as 8M and fill both page tables */
331 *pmdp = __pmd(pmd_val(*pmdp) | _PMD_PAGE_8M);
332 *(pmdp + 1) = __pmd(pmd_val(*(pmdp + 1)) | _PMD_PAGE_8M);
333
334 __set_huge_pte_at(pmdp, pte_offset_kernel(pmdp, 0), pte_val(pte));
335 __set_huge_pte_at(pmdp, pte_offset_kernel(pmdp + 1, 0), pte_val(pte) + SZ_4M);
336 } else {
337 __set_huge_pte_at(pmdp, ptep, pte_val(pte));
338 }
339}
340#else
341void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
342 pte_t pte, unsigned long sz)
343{
344 unsigned long pdsize;
345 int i;
346
347 pte = set_pte_filter(pte, addr);
348
349 /*
350 * Make sure hardware valid bit is not set. We don't do
351 * tlb flush for this update.
352 */
353 VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
354
355 if (sz < PMD_SIZE)
356 pdsize = PAGE_SIZE;
357 else if (sz < PUD_SIZE)
358 pdsize = PMD_SIZE;
359 else if (sz < P4D_SIZE)
360 pdsize = PUD_SIZE;
361 else if (sz < PGDIR_SIZE)
362 pdsize = P4D_SIZE;
363 else
364 pdsize = PGDIR_SIZE;
365
366 for (i = 0; i < sz / pdsize; i++, ptep++, addr += pdsize) {
367 __set_pte_at(mm, addr, ptep, pte, 0);
368 pte = __pte(pte_val(pte) + ((unsigned long long)pdsize / PAGE_SIZE << PFN_PTE_SHIFT));
369 }
370}
371#endif
372#endif /* CONFIG_HUGETLB_PAGE */
373
374#ifdef CONFIG_DEBUG_VM
375void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
376{
377 pgd_t *pgd;
378 p4d_t *p4d;
379 pud_t *pud;
380 pmd_t *pmd;
381 pte_t *pte;
382 spinlock_t *ptl;
383
384 if (mm == &init_mm)
385 return;
386 pgd = mm->pgd + pgd_index(addr);
387 BUG_ON(pgd_none(*pgd));
388 p4d = p4d_offset(pgd, addr);
389 BUG_ON(p4d_none(*p4d));
390 pud = pud_offset(p4d, addr);
391 BUG_ON(pud_none(*pud));
392 pmd = pmd_offset(pud, addr);
393 /*
394 * khugepaged to collapse normal pages to hugepage, first set
395 * pmd to none to force page fault/gup to take mmap_lock. After
396 * pmd is set to none, we do a pte_clear which does this assertion
397 * so if we find pmd none, return.
398 */
399 if (pmd_none(*pmd))
400 return;
401 pte = pte_offset_map_ro_nolock(mm, pmd, addr, &ptl);
402 BUG_ON(!pte);
403 assert_spin_locked(ptl);
404 pte_unmap(pte);
405}
406#endif /* CONFIG_DEBUG_VM */
407
408unsigned long vmalloc_to_phys(void *va)
409{
410 unsigned long pfn = vmalloc_to_pfn(va);
411
412 BUG_ON(!pfn);
413 return __pa(pfn_to_kaddr(pfn)) + offset_in_page(va);
414}
415EXPORT_SYMBOL_GPL(vmalloc_to_phys);
416
417/*
418 * We have 3 cases for pgds and pmds:
419 * (1) invalid (all zeroes)
420 * (2) pointer to next table, as normal; bottom 6 bits == 0
421 * (3) leaf pte for huge page _PAGE_PTE set
422 *
423 * So long as we atomically load page table pointers we are safe against teardown,
424 * we can follow the address down to the page and take a ref on it.
425 * This function need to be called with interrupts disabled. We use this variant
426 * when we have MSR[EE] = 0 but the paca->irq_soft_mask = IRQS_ENABLED
427 */
428pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
429 bool *is_thp, unsigned *hpage_shift)
430{
431 pgd_t *pgdp;
432#ifdef CONFIG_PPC64
433 p4d_t p4d, *p4dp;
434 pud_t pud, *pudp;
435#endif
436 pmd_t pmd, *pmdp;
437 pte_t *ret_pte;
438 unsigned pdshift;
439
440 if (hpage_shift)
441 *hpage_shift = 0;
442
443 if (is_thp)
444 *is_thp = false;
445
446 /*
447 * Always operate on the local stack value. This make sure the
448 * value don't get updated by a parallel THP split/collapse,
449 * page fault or a page unmap. The return pte_t * is still not
450 * stable. So should be checked there for above conditions.
451 * Top level is an exception because it is folded into p4d.
452 *
453 * On PPC32, P4D/PUD/PMD are folded into PGD so go straight to
454 * PMD level.
455 */
456 pgdp = pgdir + pgd_index(ea);
457#ifdef CONFIG_PPC64
458 p4dp = p4d_offset(pgdp, ea);
459 p4d = READ_ONCE(*p4dp);
460 pdshift = P4D_SHIFT;
461
462 if (p4d_none(p4d))
463 return NULL;
464
465 if (p4d_leaf(p4d)) {
466 ret_pte = (pte_t *)p4dp;
467 goto out;
468 }
469
470 /*
471 * Even if we end up with an unmap, the pgtable will not
472 * be freed, because we do an rcu free and here we are
473 * irq disabled
474 */
475 pdshift = PUD_SHIFT;
476 pudp = pud_offset(&p4d, ea);
477 pud = READ_ONCE(*pudp);
478
479 if (pud_none(pud))
480 return NULL;
481
482 if (pud_leaf(pud)) {
483 ret_pte = (pte_t *)pudp;
484 goto out;
485 }
486
487 pmdp = pmd_offset(&pud, ea);
488#else
489 pmdp = pmd_offset(pud_offset(p4d_offset(pgdp, ea), ea), ea);
490#endif
491 pdshift = PMD_SHIFT;
492 pmd = READ_ONCE(*pmdp);
493
494 /*
495 * A hugepage collapse is captured by this condition, see
496 * pmdp_collapse_flush.
497 */
498 if (pmd_none(pmd))
499 return NULL;
500
501#ifdef CONFIG_PPC_BOOK3S_64
502 /*
503 * A hugepage split is captured by this condition, see
504 * pmdp_invalidate.
505 *
506 * Huge page modification can be caught here too.
507 */
508 if (pmd_is_serializing(pmd))
509 return NULL;
510#endif
511
512 if (pmd_trans_huge(pmd) || pmd_devmap(pmd)) {
513 if (is_thp)
514 *is_thp = true;
515 ret_pte = (pte_t *)pmdp;
516 goto out;
517 }
518
519 if (pmd_leaf(pmd)) {
520 ret_pte = (pte_t *)pmdp;
521 goto out;
522 }
523
524 return pte_offset_kernel(&pmd, ea);
525
526out:
527 if (hpage_shift)
528 *hpage_shift = pdshift;
529 return ret_pte;
530}
531EXPORT_SYMBOL_GPL(__find_linux_pte);
532
533/* Note due to the way vm flags are laid out, the bits are XWR */
534const pgprot_t protection_map[16] = {
535 [VM_NONE] = PAGE_NONE,
536 [VM_READ] = PAGE_READONLY,
537 [VM_WRITE] = PAGE_COPY,
538 [VM_WRITE | VM_READ] = PAGE_COPY,
539 [VM_EXEC] = PAGE_EXECONLY_X,
540 [VM_EXEC | VM_READ] = PAGE_READONLY_X,
541 [VM_EXEC | VM_WRITE] = PAGE_COPY_X,
542 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY_X,
543 [VM_SHARED] = PAGE_NONE,
544 [VM_SHARED | VM_READ] = PAGE_READONLY,
545 [VM_SHARED | VM_WRITE] = PAGE_SHARED,
546 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
547 [VM_SHARED | VM_EXEC] = PAGE_EXECONLY_X,
548 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY_X,
549 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED_X,
550 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED_X
551};
552
553#ifndef CONFIG_PPC_BOOK3S_64
554DECLARE_VM_GET_PAGE_PROT
555#endif