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author | Steven Price <steven.price@arm.com> | 2020-02-03 17:36:20 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-02-04 03:05:25 +0000 |
commit | 30d621f6723b1c98a142861f7a52849d286bc7fa (patch) | |
tree | 78eae926c8b4351899aff65881dd6fc5aea064f1 /mm/ptdump.c | |
parent | c5cfae12fdd50809b16482c13a94fa6cf1e45b31 (diff) | |
download | linux-stable-30d621f6723b1c98a142861f7a52849d286bc7fa.tar.gz linux-stable-30d621f6723b1c98a142861f7a52849d286bc7fa.tar.bz2 linux-stable-30d621f6723b1c98a142861f7a52849d286bc7fa.zip |
mm: add generic ptdump
Add a generic version of page table dumping that architectures can opt-in
to.
Link: http://lkml.kernel.org/r/20191218162402.45610-20-steven.price@arm.com
Signed-off-by: Steven Price <steven.price@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/ptdump.c')
-rw-r--r-- | mm/ptdump.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/mm/ptdump.c b/mm/ptdump.c new file mode 100644 index 000000000000..868638b8e404 --- /dev/null +++ b/mm/ptdump.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/pagewalk.h> +#include <linux/ptdump.h> +#include <linux/kasan.h> + +#ifdef CONFIG_KASAN +/* + * This is an optimization for KASAN=y case. Since all kasan page tables + * eventually point to the kasan_early_shadow_page we could call note_page() + * right away without walking through lower level page tables. This saves + * us dozens of seconds (minutes for 5-level config) while checking for + * W+X mapping or reading kernel_page_tables debugfs file. + */ +static inline int note_kasan_page_table(struct mm_walk *walk, + unsigned long addr) +{ + struct ptdump_state *st = walk->private; + + st->note_page(st, addr, 5, pte_val(kasan_early_shadow_pte[0])); + + walk->action = ACTION_CONTINUE; + + return 0; +} +#endif + +static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + struct ptdump_state *st = walk->private; + pgd_t val = READ_ONCE(*pgd); + +#if CONFIG_PGTABLE_LEVELS > 4 && defined(CONFIG_KASAN) + if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d))) + return note_kasan_page_table(walk, addr); +#endif + + if (pgd_leaf(val)) + st->note_page(st, addr, 1, pgd_val(val)); + + return 0; +} + +static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + struct ptdump_state *st = walk->private; + p4d_t val = READ_ONCE(*p4d); + +#if CONFIG_PGTABLE_LEVELS > 3 && defined(CONFIG_KASAN) + if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud))) + return note_kasan_page_table(walk, addr); +#endif + + if (p4d_leaf(val)) + st->note_page(st, addr, 2, p4d_val(val)); + + return 0; +} + +static int ptdump_pud_entry(pud_t *pud, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + struct ptdump_state *st = walk->private; + pud_t val = READ_ONCE(*pud); + +#if CONFIG_PGTABLE_LEVELS > 2 && defined(CONFIG_KASAN) + if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd))) + return note_kasan_page_table(walk, addr); +#endif + + if (pud_leaf(val)) + st->note_page(st, addr, 3, pud_val(val)); + + return 0; +} + +static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + struct ptdump_state *st = walk->private; + pmd_t val = READ_ONCE(*pmd); + +#if defined(CONFIG_KASAN) + if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte))) + return note_kasan_page_table(walk, addr); +#endif + + if (pmd_leaf(val)) + st->note_page(st, addr, 4, pmd_val(val)); + + return 0; +} + +static int ptdump_pte_entry(pte_t *pte, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + struct ptdump_state *st = walk->private; + + st->note_page(st, addr, 5, pte_val(READ_ONCE(*pte))); + + return 0; +} + +static int ptdump_hole(unsigned long addr, unsigned long next, + int depth, struct mm_walk *walk) +{ + struct ptdump_state *st = walk->private; + + st->note_page(st, addr, depth + 1, 0); + + return 0; +} + +static const struct mm_walk_ops ptdump_ops = { + .pgd_entry = ptdump_pgd_entry, + .p4d_entry = ptdump_p4d_entry, + .pud_entry = ptdump_pud_entry, + .pmd_entry = ptdump_pmd_entry, + .pte_entry = ptdump_pte_entry, + .pte_hole = ptdump_hole, +}; + +void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm) +{ + const struct ptdump_range *range = st->range; + + down_read(&mm->mmap_sem); + while (range->start != range->end) { + walk_page_range_novma(mm, range->start, range->end, + &ptdump_ops, st); + range++; + } + up_read(&mm->mmap_sem); + + /* Flush out the last page */ + st->note_page(st, 0, 0, 0); +} |