On Fri, 2019-11-01 at 14:09 +0000, Steven Price wrote: > Many architectures current have a debugfs file for dumping the kernel > page tables. Currently each architecture has to implement custom > functions for this because the details of walking the page tables used > by the kernel are different between architectures. > > This series extends the capabilities of walk_page_range() so that it can > deal with the page tables of the kernel (which have no VMAs and can > contain larger huge pages than exist for user space). A generic PTDUMP > implementation is the implemented making use of the new functionality of > walk_page_range() and finally arm64 and x86 are switch to using it, > removing the custom table walkers. > > To enable a generic page table walker to walk the unusual mappings of > the kernel we need to implement a set of functions which let us know > when the walker has reached the leaf entry. After a suggestion from Will > Deacon I've chosen the name p?d_leaf() as this (hopefully) describes > the purpose (and is a new name so has no historic baggage). Some > architectures have p?d_large macros but this is easily confused with > "large pages". > > This series ends with a generic PTDUMP implemention for arm64 and x86. > > Mostly this is a clean up and there should be very little functional > change. The exceptions are: > > * arm64 PTDUMP debugfs now displays pages which aren't present (patch 22). > > * arm64 has the ability to efficiently process KASAN pages (which > previously only x86 implemented). This means that the combination of > KASAN and DEBUG_WX is now useable. > > Also available as a git tree: > git://linux-arm.org/linux-sp.git walk_page_range/v15 > > Changes since v14: > https://lore.kernel.org/lkml/20191028135910.33253-1-steven.price@xxxxxxx/ > * Switch walk_page_range() into two functions, the existing > walk_page_range() now still requires VMAs (and treats areas without a > VMA as a 'hole'). The new walk_page_range_novma() ignores VMAs and > will report the actual page table layout. This fixes the previous > breakage of /proc/<pid>/pagemap > * New patch at the end of the series which reduces the 'level' numbers > by 1 to simplify the code slightly > * Added tags Does this new version also take care of this boot crash seen with v14? Suppose it is now breaking CONFIG_EFI_PGT_DUMP=y? The full config is, https://raw.githubusercontent.com/cailca/linux-mm/master/x86.config [ 10.550313][ T0] Switched APIC routing to physical flat. [ 10.563899][ T0] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 [ 10.614633][ T0] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x1fa6f481074, max_idle_ns: 440795311917 ns [ 10.625979][ T0] Calibrating delay loop (skipped), value calculated using timer frequency.. 4391.73 BogoMIPS (lpj=21958690) [ 10.635990][ T0] pid_max: default: 131072 minimum: 1024 [ 11.259736][ T0] ---[ User Space ]--- [ 11.263737][ T0] 0x0000000000000000- 0x0000000000001000 4K RW x pte [ 11.266028][ T0] 0x0000000000001000- 0x0000000000200000 2044K pte [ 11.275992][ T0] 0x0000000000200000- 0x0000000004000000 62M pmd [ 11.285998][ T0] 0x0000000004000000- 0x0000000004076000 472K pte [ 11.296019][ T0] 0x0000000004076000- 0x0000000004200000 1576K pte [ 11.305997][ T0] 0x0000000004200000- 0x0000000011000000 206M pmd [ 11.316008][ T0] 0x0000000011000000- 0x0000000011100000 1M pte [ 11.326008][ T0] 0x0000000011100000- 0x0000000011200000 1M pte [ 11.335990][ T0] 0x0000000011200000- 0x0000000011800000 6M pmd [ 11.346054][ T0] ================================================================== [ 11.354074][ T0] BUG: KASAN: wild-memory-access in ptdump_pte_entry+0x39/0x60 [ 11.355975][ T0] Read of size 8 at addr 000f887fee5ff000 by task swapper/0/0 [ 11.355975][ T0] [ 11.355975][ T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc5-mm1+ #1 [ 11.355975][ T0] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 [ 11.355975][ T0] Call Trace: [ 11.355975][ T0] dump_stack+0xa0/0xea [ 11.355975][ T0] __kasan_report.cold.7+0xb0/0xc0 [ 11.355975][ T0] ? note_page+0x7f8/0xa70 [ 11.355975][ T0] ? ptdump_pte_entry+0x39/0x60 [ 11.355975][ T0] ? ptdump_walk_pgd_level_core+0x1b0/0x1b0 [ 11.355975][ T0] kasan_report+0x12/0x20 [ 11.355975][ T0] __asan_load8+0x71/0xa0 [ 11.355975][ T0] ptdump_pte_entry+0x39/0x60 [ 11.355975][ T0] walk_pgd_range+0xb75/0xce0 [ 11.355975][ T0] __walk_page_range+0x206/0x230 [ 11.355975][ T0] ? vmacache_find+0x3a/0x170 [ 11.355975][ T0] walk_page_range+0x136/0x210 [ 11.355975][ T0] ? __walk_page_range+0x230/0x230 [ 11.355975][ T0] ? find_held_lock+0xca/0xf0 [ 11.355975][ T0] ptdump_walk_pgd+0x76/0xd0 [ 11.355975][ T0] ptdump_walk_pgd_level_core+0x13b/0x1b0 [ 11.355975][ T0] ? hugetlb_get_unmapped_area+0x5b0/0x5b0 [ 11.355975][ T0] ? trace_hardirqs_on+0x3a/0x160 [ 11.355975][ T0] ? ptdump_walk_pgd_level_core+0x1b0/0x1b0 [ 11.355975][ T0] ? efi_delete_dummy_variable+0xa9/0xd0 [ 11.355975][ T0] ? __enc_copy+0x90/0x90 [ 11.355975][ T0] ptdump_walk_pgd_level+0x15/0x20 [ 11.355975][ T0] efi_dump_pagetable+0x35/0x37 [ 11.355975][ T0] efi_enter_virtual_mode+0x72a/0x737 [ 11.355975][ T0] start_kernel+0x607/0x6a9 [ 11.355975][ T0] ? thread_stack_cache_init+0xb/0xb [ 11.355975][ T0] ? idt_setup_from_table+0xd9/0x130 [ 11.355975][ T0] x86_64_start_reservations+0x24/0x26 [ 11.355975][ T0] x86_64_start_kernel+0xf4/0xfb [ 11.355975][ T0] secondary_startup_64+0xb6/0xc0 [ 11.355975][ T0] ================================================================== [ 11.355975][ T0] Disabling lock debugging due to kernel taint [ 11.355991][ T0] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 11.364049][ T0] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B 5.4.0-rc5-mm1+ #1 [ 11.365975][ T0] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 [ 11.365975][ T0] RIP: 0010:ptdump_pte_entry+0x39/0x60 [ 11.365975][ T0] Code: 55 41 54 49 89 fc 48 8d 79 18 53 48 89 cb e8 5e 0e fa ff 48 8b 5b 18 48 89 df e8 52 0e fa ff 4c 89 e7 4c 8b 2b e8 47 0e fa ff <49> 8b 0c 24 4c 89 f6 48 89 df ba 05 00 00 00 e8 03 1d 9b 00 31 c0 [ 11.365975][ T0] RSP: 0000:ffffffffaf8079d0 EFLAGS: 00010282 [ 11.365975][ T0] RAX: 0000000000000000 RBX: ffffffffaf807cf0 RCX: ffffffffae374306 [ 11.365975][ T0] RDX: 0000000000000007 RSI: dffffc0000000000 RDI: ffffffffafef2bf4 [ 11.365975][ T0] RBP: ffffffffaf8079f0 R08: fffffbfff5fdbb22 R09: fffffbfff5fdbb22 [ 11.365975][ T0] R10: fffffbfff5fdbb21 R11: ffffffffafedd90b R12: 000f887fee5ff000 [ 11.365975][ T0] R13: ffffffffae2aee40 R14: 0000000011a00000 R15: 0000000011a01000 [ 11.365975][ T0] FS: 0000000000000000(0000) GS:ffff888843400000(0000) knlGS:0000000000000000 [ 11.365975][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 11.365975][ T0] CR2: ffff8890779ff000 CR3: 0000000baf412000 CR4: 00000000000406b0 [ 11.365975][ T0] Call Trace: [ 11.365975][ T0] walk_pgd_range+0xb75/0xce0 [ 11.365975][ T0] __walk_page_range+0x206/0x230 [ 11.365975][ T0] ? vmacache_find+0x3a/0x170 [ 11.365975][ T0] walk_page_range+0x136/0x210 [ 11.365975][ T0] ? __walk_page_range+0x230/0x230 [ 11.365975][ T0] ? find_held_lock+0xca/0xf0 [ 11.365975][ T0] ptdump_walk_pgd+0x76/0xd0 [ 11.365975][ T0] ptdump_walk_pgd_level_core+0x13b/0x1b0 [ 11.365975][ T0] ? hugetlb_get_unmapped_area+0x5b0/0x5b0 [ 11.365975][ T0] ? trace_hardirqs_on+0x3a/0x160 [ 11.365975][ T0] ? ptdump_walk_pgd_level_core+0x1b0/0x1b0 [ 11.365975][ T0] ? efi_delete_dummy_variable+0xa9/0xd0 [ 11.365975][ T0] ? __enc_copy+0x90/0x90 [ 11.365975][ T0] ptdump_walk_pgd_level+0x15/0x20 [ 11.365975][ T0] efi_dump_pagetable+0x35/0x37 [ 11.365975][ T0] efi_enter_virtual_mode+0x72a/0x737 [ 11.365975][ T0] start_kernel+0x607/0x6a9 [ 11.365975][ T0] ? thread_stack_cache_init+0xb/0xb [ 11.365975][ T0] ? idt_setup_from_table+0xd9/0x130 [ 11.365975][ T0] x86_64_start_reservations+0x24/0x26 [ 11.365975][ T0] x86_64_start_kernel+0xf4/0xfb [ 11.365975][ T0] secondary_startup_64+0xb6/0xc0 [ 11.365975][ T0] Modules linked in: [ 11.365988][ T0] ---[ end trace 8e90dc89e2468d55 ]--- [ 11.375984][ T0] RIP: 0010:ptdump_pte_entry+0x39/0x60 [ 11.381335][ T0] Code: 55 41 54 49 89 fc 48 8d 79 18 53 48 89 cb e8 5e 0e fa ff 48 8b 5b 18 48 89 df e8 52 0e fa ff 4c 89 e7 4c 8b 2b e8 47 0e fa ff <49> 8b 0c 24 4c 89 f6 48 89 df ba 05 00 00 00 e8 03 1d 9b 00 31 c0 [ 11.385982][ T0] RSP: 0000:ffffffffaf8079d0 EFLAGS: 00010282 [ 11.395982][ T0] RAX: 0000000000000000 RBX: ffffffffaf807cf0 RCX: ffffffffae374306 [ 11.403864][ T0] RDX: 0000000000000007 RSI: dffffc0000000000 RDI: ffffffffafef2bf4 [ 11.405982][ T0] RBP: ffffffffaf8079f0 R08: fffffbfff5fdbb22 R09: fffffbfff5fdbb22 [ 11.415982][ T0] R10: fffffbfff5fdbb21 R11: ffffffffafedd90b R12: 000f887fee5ff000 [ 11.425982][ T0] R13: ffffffffae2aee40 R14: 0000000011a00000 R15: 0000000011a01000 [ 11.435982][ T0] FS: 0000000000000000(0000) GS:ffff888843400000(0000) knlGS:0000000000000000 [ 11.445982][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 11.452466][ T0] CR2: ffff8890779ff000 CR3: 0000000baf412000 CR4: 00000000000406b0 [ 11.455981][ T0] Kernel panic - not syncing: Fatal exception [ 11.462246][ T0] ---[ end Kernel panic - not syncing: Fatal exception ]--- > > Changes since v13: > https://lore.kernel.org/lkml/20191024093716.49420-1-steven.price@xxxxxxx/ > * Fixed typo in arc definition of pmd_leaf() spotted by the kbuild test > robot > * Added tags > > Changes since v12: > https://lore.kernel.org/lkml/20191018101248.33727-1-steven.price@xxxxxxx/ > * Correct code format in riscv pud_leaf()/pmd_leaf() > * v12 may not have reached everyone because of mail server problems > (which are now hopefully resolved!) > > Changes since v11: > https://lore.kernel.org/lkml/20191007153822.16518-1-steven.price@xxxxxxx/ > * Use "-1" as dummy depth parameter in patch 14. > > Changes since v10: > https://lore.kernel.org/lkml/20190731154603.41797-1-steven.price@xxxxxxx/ > * Rebased to v5.4-rc1 - mainly various updates to deal with the > splitting out of ops from struct mm_walk. > * Deal with PGD_LEVEL_MULT not always being constant on x86. > > Changes since v9: > https://lore.kernel.org/lkml/20190722154210.42799-1-steven.price@xxxxxxx/ > * Moved generic macros to first page in the series and explained the > macro naming in the commit message. > * mips: Moved macros to pgtable.h as they are now valid for both 32 and 64 > bit > * x86: Dropped patch which changed the debugfs output for x86, instead > we have... > * new patch adding 'depth' parameter to pte_hole. This is used to > provide the necessary information to output lines for 'holes' in the > debugfs files > * new patch changing arm64 debugfs output to include holes to match x86 > * generic ptdump KASAN handling has been simplified and now works with > CONFIG_DEBUG_VIRTUAL. > > Changes since v8: > https://lore.kernel.org/lkml/20190403141627.11664-1-steven.price@xxxxxxx/ > * Rename from p?d_large() to p?d_leaf() > * Dropped patches migrating arm64/x86 custom walkers to > walk_page_range() in favour of adding a generic PTDUMP implementation > and migrating arm64/x86 to that instead. > * Rebased to v5.3-rc1 > > Steven Price (23): > mm: Add generic p?d_leaf() macros > arc: mm: Add p?d_leaf() definitions > arm: mm: Add p?d_leaf() definitions > arm64: mm: Add p?d_leaf() definitions > mips: mm: Add p?d_leaf() definitions > powerpc: mm: Add p?d_leaf() definitions > riscv: mm: Add p?d_leaf() definitions > s390: mm: Add p?d_leaf() definitions > sparc: mm: Add p?d_leaf() definitions > x86: mm: Add p?d_leaf() definitions > mm: pagewalk: Add p4d_entry() and pgd_entry() > mm: pagewalk: Allow walking without vma > mm: pagewalk: Add test_p?d callbacks > mm: pagewalk: Add 'depth' parameter to pte_hole > x86: mm: Point to struct seq_file from struct pg_state > x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct > x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct > x86: mm: Convert ptdump_walk_pgd_level_core() to take an mm_struct > mm: Add generic ptdump > x86: mm: Convert dump_pagetables to use walk_page_range > arm64: mm: Convert mm/dump.c to use walk_page_range() > arm64: mm: Display non-present entries in ptdump > mm: ptdump: Reduce level numbers by 1 in note_page() > > arch/arc/include/asm/pgtable.h | 1 + > arch/arm/include/asm/pgtable-2level.h | 1 + > arch/arm/include/asm/pgtable-3level.h | 1 + > arch/arm64/Kconfig | 1 + > arch/arm64/Kconfig.debug | 19 +- > arch/arm64/include/asm/pgtable.h | 2 + > arch/arm64/include/asm/ptdump.h | 8 +- > arch/arm64/mm/Makefile | 4 +- > arch/arm64/mm/dump.c | 148 +++----- > arch/arm64/mm/mmu.c | 4 +- > arch/arm64/mm/ptdump_debugfs.c | 2 +- > arch/mips/include/asm/pgtable.h | 5 + > arch/powerpc/include/asm/book3s/64/pgtable.h | 30 +- > arch/riscv/include/asm/pgtable-64.h | 7 + > arch/riscv/include/asm/pgtable.h | 7 + > arch/s390/include/asm/pgtable.h | 2 + > arch/sparc/include/asm/pgtable_64.h | 2 + > arch/x86/Kconfig | 1 + > arch/x86/Kconfig.debug | 20 +- > arch/x86/include/asm/pgtable.h | 10 +- > arch/x86/mm/Makefile | 4 +- > arch/x86/mm/debug_pagetables.c | 8 +- > arch/x86/mm/dump_pagetables.c | 343 +++++-------------- > arch/x86/platform/efi/efi_32.c | 2 +- > arch/x86/platform/efi/efi_64.c | 4 +- > drivers/firmware/efi/arm-runtime.c | 2 +- > fs/proc/task_mmu.c | 4 +- > include/asm-generic/pgtable.h | 20 ++ > include/linux/pagewalk.h | 42 ++- > include/linux/ptdump.h | 22 ++ > mm/Kconfig.debug | 21 ++ > mm/Makefile | 1 + > mm/hmm.c | 8 +- > mm/migrate.c | 5 +- > mm/mincore.c | 1 + > mm/pagewalk.c | 126 +++++-- > mm/ptdump.c | 151 ++++++++ > 37 files changed, 586 insertions(+), 453 deletions(-) > create mode 100644 include/linux/ptdump.h > create mode 100644 mm/ptdump.c >
