130d621f6SSteven Price // SPDX-License-Identifier: GPL-2.0 230d621f6SSteven Price 330d621f6SSteven Price #include <linux/pagewalk.h> 4*565474afSChristophe Leroy #include <linux/debugfs.h> 530d621f6SSteven Price #include <linux/ptdump.h> 630d621f6SSteven Price #include <linux/kasan.h> 730d621f6SSteven Price 80fea6e9aSAndrey Konovalov #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) 930d621f6SSteven Price /* 1030d621f6SSteven Price * This is an optimization for KASAN=y case. Since all kasan page tables 1130d621f6SSteven Price * eventually point to the kasan_early_shadow_page we could call note_page() 1230d621f6SSteven Price * right away without walking through lower level page tables. This saves 1330d621f6SSteven Price * us dozens of seconds (minutes for 5-level config) while checking for 1430d621f6SSteven Price * W+X mapping or reading kernel_page_tables debugfs file. 1530d621f6SSteven Price */ 1630d621f6SSteven Price static inline int note_kasan_page_table(struct mm_walk *walk, 1730d621f6SSteven Price unsigned long addr) 1830d621f6SSteven Price { 1930d621f6SSteven Price struct ptdump_state *st = walk->private; 2030d621f6SSteven Price 21f8f0d0b6SSteven Price st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); 2230d621f6SSteven Price 2330d621f6SSteven Price walk->action = ACTION_CONTINUE; 2430d621f6SSteven Price 2530d621f6SSteven Price return 0; 2630d621f6SSteven Price } 2730d621f6SSteven Price #endif 2830d621f6SSteven Price 2930d621f6SSteven Price static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, 3030d621f6SSteven Price unsigned long next, struct mm_walk *walk) 3130d621f6SSteven Price { 3230d621f6SSteven Price struct ptdump_state *st = walk->private; 3330d621f6SSteven Price pgd_t val = READ_ONCE(*pgd); 3430d621f6SSteven Price 350fea6e9aSAndrey Konovalov #if CONFIG_PGTABLE_LEVELS > 4 && \ 360fea6e9aSAndrey Konovalov (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) 3730d621f6SSteven Price if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d))) 3830d621f6SSteven Price return note_kasan_page_table(walk, addr); 3930d621f6SSteven Price #endif 4030d621f6SSteven Price 411494e0c3SSteven Price if (st->effective_prot) 421494e0c3SSteven Price st->effective_prot(st, 0, pgd_val(val)); 431494e0c3SSteven Price 44d8d55f56SMuchun Song if (pgd_leaf(val)) { 45f8f0d0b6SSteven Price st->note_page(st, addr, 0, pgd_val(val)); 46d8d55f56SMuchun Song walk->action = ACTION_CONTINUE; 47d8d55f56SMuchun Song } 4830d621f6SSteven Price 4930d621f6SSteven Price return 0; 5030d621f6SSteven Price } 5130d621f6SSteven Price 5230d621f6SSteven Price static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, 5330d621f6SSteven Price unsigned long next, struct mm_walk *walk) 5430d621f6SSteven Price { 5530d621f6SSteven Price struct ptdump_state *st = walk->private; 5630d621f6SSteven Price p4d_t val = READ_ONCE(*p4d); 5730d621f6SSteven Price 580fea6e9aSAndrey Konovalov #if CONFIG_PGTABLE_LEVELS > 3 && \ 590fea6e9aSAndrey Konovalov (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) 6030d621f6SSteven Price if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud))) 6130d621f6SSteven Price return note_kasan_page_table(walk, addr); 6230d621f6SSteven Price #endif 6330d621f6SSteven Price 641494e0c3SSteven Price if (st->effective_prot) 651494e0c3SSteven Price st->effective_prot(st, 1, p4d_val(val)); 661494e0c3SSteven Price 67d8d55f56SMuchun Song if (p4d_leaf(val)) { 68f8f0d0b6SSteven Price st->note_page(st, addr, 1, p4d_val(val)); 69d8d55f56SMuchun Song walk->action = ACTION_CONTINUE; 70d8d55f56SMuchun Song } 7130d621f6SSteven Price 7230d621f6SSteven Price return 0; 7330d621f6SSteven Price } 7430d621f6SSteven Price 7530d621f6SSteven Price static int ptdump_pud_entry(pud_t *pud, unsigned long addr, 7630d621f6SSteven Price unsigned long next, struct mm_walk *walk) 7730d621f6SSteven Price { 7830d621f6SSteven Price struct ptdump_state *st = walk->private; 7930d621f6SSteven Price pud_t val = READ_ONCE(*pud); 8030d621f6SSteven Price 810fea6e9aSAndrey Konovalov #if CONFIG_PGTABLE_LEVELS > 2 && \ 820fea6e9aSAndrey Konovalov (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) 8330d621f6SSteven Price if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd))) 8430d621f6SSteven Price return note_kasan_page_table(walk, addr); 8530d621f6SSteven Price #endif 8630d621f6SSteven Price 871494e0c3SSteven Price if (st->effective_prot) 881494e0c3SSteven Price st->effective_prot(st, 2, pud_val(val)); 891494e0c3SSteven Price 90d8d55f56SMuchun Song if (pud_leaf(val)) { 91f8f0d0b6SSteven Price st->note_page(st, addr, 2, pud_val(val)); 92d8d55f56SMuchun Song walk->action = ACTION_CONTINUE; 93d8d55f56SMuchun Song } 9430d621f6SSteven Price 9530d621f6SSteven Price return 0; 9630d621f6SSteven Price } 9730d621f6SSteven Price 9830d621f6SSteven Price static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, 9930d621f6SSteven Price unsigned long next, struct mm_walk *walk) 10030d621f6SSteven Price { 10130d621f6SSteven Price struct ptdump_state *st = walk->private; 10230d621f6SSteven Price pmd_t val = READ_ONCE(*pmd); 10330d621f6SSteven Price 1040fea6e9aSAndrey Konovalov #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) 10530d621f6SSteven Price if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte))) 10630d621f6SSteven Price return note_kasan_page_table(walk, addr); 10730d621f6SSteven Price #endif 10830d621f6SSteven Price 1091494e0c3SSteven Price if (st->effective_prot) 1101494e0c3SSteven Price st->effective_prot(st, 3, pmd_val(val)); 111d8d55f56SMuchun Song if (pmd_leaf(val)) { 112f8f0d0b6SSteven Price st->note_page(st, addr, 3, pmd_val(val)); 113d8d55f56SMuchun Song walk->action = ACTION_CONTINUE; 114d8d55f56SMuchun Song } 11530d621f6SSteven Price 11630d621f6SSteven Price return 0; 11730d621f6SSteven Price } 11830d621f6SSteven Price 11930d621f6SSteven Price static int ptdump_pte_entry(pte_t *pte, unsigned long addr, 12030d621f6SSteven Price unsigned long next, struct mm_walk *walk) 12130d621f6SSteven Price { 12230d621f6SSteven Price struct ptdump_state *st = walk->private; 123426931e7SRyan Roberts pte_t val = ptep_get_lockless(pte); 12430d621f6SSteven Price 1251494e0c3SSteven Price if (st->effective_prot) 1261494e0c3SSteven Price st->effective_prot(st, 4, pte_val(val)); 1271494e0c3SSteven Price 1281494e0c3SSteven Price st->note_page(st, addr, 4, pte_val(val)); 12930d621f6SSteven Price 13030d621f6SSteven Price return 0; 13130d621f6SSteven Price } 13230d621f6SSteven Price 13330d621f6SSteven Price static int ptdump_hole(unsigned long addr, unsigned long next, 13430d621f6SSteven Price int depth, struct mm_walk *walk) 13530d621f6SSteven Price { 13630d621f6SSteven Price struct ptdump_state *st = walk->private; 13730d621f6SSteven Price 138f8f0d0b6SSteven Price st->note_page(st, addr, depth, 0); 13930d621f6SSteven Price 14030d621f6SSteven Price return 0; 14130d621f6SSteven Price } 14230d621f6SSteven Price 14330d621f6SSteven Price static const struct mm_walk_ops ptdump_ops = { 14430d621f6SSteven Price .pgd_entry = ptdump_pgd_entry, 14530d621f6SSteven Price .p4d_entry = ptdump_p4d_entry, 14630d621f6SSteven Price .pud_entry = ptdump_pud_entry, 14730d621f6SSteven Price .pmd_entry = ptdump_pmd_entry, 14830d621f6SSteven Price .pte_entry = ptdump_pte_entry, 14930d621f6SSteven Price .pte_hole = ptdump_hole, 15030d621f6SSteven Price }; 15130d621f6SSteven Price 152e47690d7SSteven Price void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd) 15330d621f6SSteven Price { 15430d621f6SSteven Price const struct ptdump_range *range = st->range; 15530d621f6SSteven Price 1568782fb61SSteven Price mmap_write_lock(mm); 15730d621f6SSteven Price while (range->start != range->end) { 15830d621f6SSteven Price walk_page_range_novma(mm, range->start, range->end, 159e47690d7SSteven Price &ptdump_ops, pgd, st); 16030d621f6SSteven Price range++; 16130d621f6SSteven Price } 1628782fb61SSteven Price mmap_write_unlock(mm); 16330d621f6SSteven Price 16430d621f6SSteven Price /* Flush out the last page */ 165f8f0d0b6SSteven Price st->note_page(st, 0, -1, 0); 16630d621f6SSteven Price } 167*565474afSChristophe Leroy 168*565474afSChristophe Leroy static int check_wx_show(struct seq_file *m, void *v) 169*565474afSChristophe Leroy { 170*565474afSChristophe Leroy if (ptdump_check_wx()) 171*565474afSChristophe Leroy seq_puts(m, "SUCCESS\n"); 172*565474afSChristophe Leroy else 173*565474afSChristophe Leroy seq_puts(m, "FAILED\n"); 174*565474afSChristophe Leroy 175*565474afSChristophe Leroy return 0; 176*565474afSChristophe Leroy } 177*565474afSChristophe Leroy 178*565474afSChristophe Leroy DEFINE_SHOW_ATTRIBUTE(check_wx); 179*565474afSChristophe Leroy 180*565474afSChristophe Leroy static int ptdump_debugfs_init(void) 181*565474afSChristophe Leroy { 182*565474afSChristophe Leroy debugfs_create_file("check_wx_pages", 0400, NULL, NULL, &check_wx_fops); 183*565474afSChristophe Leroy 184*565474afSChristophe Leroy return 0; 185*565474afSChristophe Leroy } 186*565474afSChristophe Leroy 187*565474afSChristophe Leroy device_initcall(ptdump_debugfs_init); 188