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458376913d
READ_ONCE() cannot be used for reading PTEs. Use ptep_get() instead, to
avoid the following errors:
CC mm/ptdump.o
In file included from <command-line>:
mm/ptdump.c: In function 'ptdump_pte_entry':
include/linux/compiler_types.h:320:38: error: call to '__compiletime_assert_207' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE().
320 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:301:4: note: in definition of macro '__compiletime_assert'
301 | prefix ## suffix(); \
| ^~~~~~
include/linux/compiler_types.h:320:2: note: in expansion of macro '_compiletime_assert'
320 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:2: note: in expansion of macro 'compiletime_assert'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:49:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
49 | compiletime_assert_rwonce_type(x); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/ptdump.c:114:14: note: in expansion of macro 'READ_ONCE'
114 | pte_t val = READ_ONCE(*pte);
| ^~~~~~~~~
make[2]: *** [mm/ptdump.o] Error 1
See commit 481e980a7c ("mm: Allow arches to provide ptep_get()") and
commit c0e1c8c22b ("powerpc/8xx: Provide ptep_get() with 16k pages")
for details.
Link: https://lkml.kernel.org/r/912b349e2bcaa88939904815ca0af945740c6bd4.1618478922.git.christophe.leroy@csgroup.eu
Fixes: 30d621f672 ("mm: add generic ptdump")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
157 lines
4 KiB
C
157 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/pagewalk.h>
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#include <linux/ptdump.h>
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#include <linux/kasan.h>
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#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
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/*
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* This is an optimization for KASAN=y case. Since all kasan page tables
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* eventually point to the kasan_early_shadow_page we could call note_page()
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* right away without walking through lower level page tables. This saves
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* us dozens of seconds (minutes for 5-level config) while checking for
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* W+X mapping or reading kernel_page_tables debugfs file.
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*/
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static inline int note_kasan_page_table(struct mm_walk *walk,
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unsigned long addr)
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{
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struct ptdump_state *st = walk->private;
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st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]));
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walk->action = ACTION_CONTINUE;
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return 0;
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}
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#endif
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static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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pgd_t val = READ_ONCE(*pgd);
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#if CONFIG_PGTABLE_LEVELS > 4 && \
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(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
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if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (st->effective_prot)
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st->effective_prot(st, 0, pgd_val(val));
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if (pgd_leaf(val))
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st->note_page(st, addr, 0, pgd_val(val));
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return 0;
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}
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static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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p4d_t val = READ_ONCE(*p4d);
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#if CONFIG_PGTABLE_LEVELS > 3 && \
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(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
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if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (st->effective_prot)
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st->effective_prot(st, 1, p4d_val(val));
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if (p4d_leaf(val))
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st->note_page(st, addr, 1, p4d_val(val));
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return 0;
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}
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static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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pud_t val = READ_ONCE(*pud);
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#if CONFIG_PGTABLE_LEVELS > 2 && \
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(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
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if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (st->effective_prot)
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st->effective_prot(st, 2, pud_val(val));
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if (pud_leaf(val))
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st->note_page(st, addr, 2, pud_val(val));
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return 0;
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}
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static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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pmd_t val = READ_ONCE(*pmd);
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#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
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if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (st->effective_prot)
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st->effective_prot(st, 3, pmd_val(val));
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if (pmd_leaf(val))
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st->note_page(st, addr, 3, pmd_val(val));
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return 0;
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}
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static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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pte_t val = ptep_get(pte);
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if (st->effective_prot)
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st->effective_prot(st, 4, pte_val(val));
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st->note_page(st, addr, 4, pte_val(val));
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return 0;
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}
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static int ptdump_hole(unsigned long addr, unsigned long next,
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int depth, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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st->note_page(st, addr, depth, 0);
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return 0;
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}
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static const struct mm_walk_ops ptdump_ops = {
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.pgd_entry = ptdump_pgd_entry,
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.p4d_entry = ptdump_p4d_entry,
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.pud_entry = ptdump_pud_entry,
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.pmd_entry = ptdump_pmd_entry,
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.pte_entry = ptdump_pte_entry,
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.pte_hole = ptdump_hole,
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};
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void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd)
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{
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const struct ptdump_range *range = st->range;
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mmap_read_lock(mm);
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while (range->start != range->end) {
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walk_page_range_novma(mm, range->start, range->end,
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&ptdump_ops, pgd, st);
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range++;
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}
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mmap_read_unlock(mm);
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/* Flush out the last page */
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st->note_page(st, 0, -1, 0);
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}
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