From: Steven Price <steven.price@arm.com> To: linux-mm@kvack.org Cc: "Steven Price" <steven.price@arm.com>, "Andy Lutomirski" <luto@kernel.org>, "Ard Biesheuvel" <ard.biesheuvel@linaro.org>, "Arnd Bergmann" <arnd@arndb.de>, "Borislav Petkov" <bp@alien8.de>, "Catalin Marinas" <catalin.marinas@arm.com>, "Dave Hansen" <dave.hansen@linux.intel.com>, "Ingo Molnar" <mingo@redhat.com>, "James Morse" <james.morse@arm.com>, "Jérôme Glisse" <jglisse@redhat.com>, "Peter Zijlstra" <peterz@infradead.org>, "Thomas Gleixner" <tglx@linutronix.de>, "Will Deacon" <will@kernel.org>, x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Mark Rutland" <Mark.Rutland@arm.com>, "Liang, Kan" <kan.liang@linux.intel.com>, "Andrew Morton" <akpm@linux-foundation.org> Subject: [PATCH v10 19/22] mm: Add generic ptdump Date: Wed, 31 Jul 2019 16:46:00 +0100 [thread overview] Message-ID: <20190731154603.41797-20-steven.price@arm.com> (raw) In-Reply-To: <20190731154603.41797-1-steven.price@arm.com> Add a generic version of page table dumping that architectures can opt-in to Signed-off-by: Steven Price <steven.price@arm.com> --- include/linux/ptdump.h | 19 ++++++ mm/Kconfig.debug | 21 ++++++ mm/Makefile | 1 + mm/ptdump.c | 151 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 192 insertions(+) create mode 100644 include/linux/ptdump.h create mode 100644 mm/ptdump.c diff --git a/include/linux/ptdump.h b/include/linux/ptdump.h new file mode 100644 index 000000000000..eb8e78154be3 --- /dev/null +++ b/include/linux/ptdump.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_PTDUMP_H +#define _LINUX_PTDUMP_H + +struct ptdump_range { + unsigned long start; + unsigned long end; +}; + +struct ptdump_state { + void (*note_page)(struct ptdump_state *st, unsigned long addr, + int level, unsigned long val); + const struct ptdump_range *range; +}; + +void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm); + +#endif /* _LINUX_PTDUMP_H */ diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 82b6a20898bd..7ad939b7140f 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -115,3 +115,24 @@ config DEBUG_RODATA_TEST depends on STRICT_KERNEL_RWX ---help--- This option enables a testcase for the setting rodata read-only. + +config GENERIC_PTDUMP + bool + +config PTDUMP_CORE + bool + +config PTDUMP_DEBUGFS + bool "Export kernel pagetable layout to userspace via debugfs" + depends on DEBUG_KERNEL + depends on DEBUG_FS + depends on GENERIC_PTDUMP + select PTDUMP_CORE + help + Say Y here if you want to show the kernel pagetable layout in a + debugfs file. This information is only useful for kernel developers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + + If in doubt, say N. diff --git a/mm/Makefile b/mm/Makefile index 338e528ad436..750a4c12d5da 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -104,3 +104,4 @@ obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o obj-$(CONFIG_PERCPU_STATS) += percpu-stats.o obj-$(CONFIG_HMM_MIRROR) += hmm.o obj-$(CONFIG_MEMFD_CREATE) += memfd.o +obj-$(CONFIG_PTDUMP_CORE) += ptdump.o diff --git a/mm/ptdump.c b/mm/ptdump.c new file mode 100644 index 000000000000..186af468d1a1 --- /dev/null +++ b/mm/ptdump.c @@ -0,0 +1,151 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/mm.h> +#include <linux/ptdump.h> +#include <linux/kasan.h> + +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 (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 (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 (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 (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; +} + +#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])); + return 1; +} + +static int ptdump_test_p4d(unsigned long addr, unsigned long next, + p4d_t *p4d, struct mm_walk *walk) +{ +#if CONFIG_PGTABLE_LEVELS > 4 + if (p4d == lm_alias(kasan_early_shadow_p4d)) + return note_kasan_page_table(walk, addr); +#endif + return 0; +} + +static int ptdump_test_pud(unsigned long addr, unsigned long next, + pud_t *pud, struct mm_walk *walk) +{ +#if CONFIG_PGTABLE_LEVELS > 3 + if (pud == lm_alias(kasan_early_shadow_pud)) + return note_kasan_page_table(walk, addr); +#endif + return 0; +} + +static int ptdump_test_pmd(unsigned long addr, unsigned long next, + pmd_t *pmd, struct mm_walk *walk) +{ +#if CONFIG_PGTABLE_LEVELS > 2 + if (pmd == lm_alias(kasan_early_shadow_pmd)) + return note_kasan_page_table(walk, addr); +#endif + return 0; +} +#endif /* CONFIG_KASAN */ + +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; +} + +void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm) +{ + struct mm_walk walk = { + .mm = mm, + .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, +#ifdef CONFIG_KASAN + .test_p4d = ptdump_test_p4d, + .test_pud = ptdump_test_pud, + .test_pmd = ptdump_test_pmd, +#endif + .pte_hole = ptdump_hole, + .private = st + }; + const struct ptdump_range *range = st->range; + + down_read(&mm->mmap_sem); + while (range->start != range->end) { + walk_page_range(range->start, range->end, &walk); + range++; + } + up_read(&mm->mmap_sem); + + /* Flush out the last page */ + st->note_page(st, 0, 0, 0); +} -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: Steven Price <steven.price@arm.com> To: linux-mm@kvack.org Cc: "Mark Rutland" <Mark.Rutland@arm.com>, x86@kernel.org, "Arnd Bergmann" <arnd@arndb.de>, "Ard Biesheuvel" <ard.biesheuvel@linaro.org>, "Peter Zijlstra" <peterz@infradead.org>, "Catalin Marinas" <catalin.marinas@arm.com>, "Dave Hansen" <dave.hansen@linux.intel.com>, linux-kernel@vger.kernel.org, "Steven Price" <steven.price@arm.com>, "Jérôme Glisse" <jglisse@redhat.com>, "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>, "Andy Lutomirski" <luto@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, "James Morse" <james.morse@arm.com>, "Thomas Gleixner" <tglx@linutronix.de>, "Will Deacon" <will@kernel.org>, "Andrew Morton" <akpm@linux-foundation.org>, linux-arm-kernel@lists.infradead.org, "Liang, Kan" <kan.liang@linux.intel.com> Subject: [PATCH v10 19/22] mm: Add generic ptdump Date: Wed, 31 Jul 2019 16:46:00 +0100 [thread overview] Message-ID: <20190731154603.41797-20-steven.price@arm.com> (raw) In-Reply-To: <20190731154603.41797-1-steven.price@arm.com> Add a generic version of page table dumping that architectures can opt-in to Signed-off-by: Steven Price <steven.price@arm.com> --- include/linux/ptdump.h | 19 ++++++ mm/Kconfig.debug | 21 ++++++ mm/Makefile | 1 + mm/ptdump.c | 151 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 192 insertions(+) create mode 100644 include/linux/ptdump.h create mode 100644 mm/ptdump.c diff --git a/include/linux/ptdump.h b/include/linux/ptdump.h new file mode 100644 index 000000000000..eb8e78154be3 --- /dev/null +++ b/include/linux/ptdump.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_PTDUMP_H +#define _LINUX_PTDUMP_H + +struct ptdump_range { + unsigned long start; + unsigned long end; +}; + +struct ptdump_state { + void (*note_page)(struct ptdump_state *st, unsigned long addr, + int level, unsigned long val); + const struct ptdump_range *range; +}; + +void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm); + +#endif /* _LINUX_PTDUMP_H */ diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 82b6a20898bd..7ad939b7140f 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -115,3 +115,24 @@ config DEBUG_RODATA_TEST depends on STRICT_KERNEL_RWX ---help--- This option enables a testcase for the setting rodata read-only. + +config GENERIC_PTDUMP + bool + +config PTDUMP_CORE + bool + +config PTDUMP_DEBUGFS + bool "Export kernel pagetable layout to userspace via debugfs" + depends on DEBUG_KERNEL + depends on DEBUG_FS + depends on GENERIC_PTDUMP + select PTDUMP_CORE + help + Say Y here if you want to show the kernel pagetable layout in a + debugfs file. This information is only useful for kernel developers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + + If in doubt, say N. diff --git a/mm/Makefile b/mm/Makefile index 338e528ad436..750a4c12d5da 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -104,3 +104,4 @@ obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o obj-$(CONFIG_PERCPU_STATS) += percpu-stats.o obj-$(CONFIG_HMM_MIRROR) += hmm.o obj-$(CONFIG_MEMFD_CREATE) += memfd.o +obj-$(CONFIG_PTDUMP_CORE) += ptdump.o diff --git a/mm/ptdump.c b/mm/ptdump.c new file mode 100644 index 000000000000..186af468d1a1 --- /dev/null +++ b/mm/ptdump.c @@ -0,0 +1,151 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/mm.h> +#include <linux/ptdump.h> +#include <linux/kasan.h> + +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 (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 (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 (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 (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; +} + +#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])); + return 1; +} + +static int ptdump_test_p4d(unsigned long addr, unsigned long next, + p4d_t *p4d, struct mm_walk *walk) +{ +#if CONFIG_PGTABLE_LEVELS > 4 + if (p4d == lm_alias(kasan_early_shadow_p4d)) + return note_kasan_page_table(walk, addr); +#endif + return 0; +} + +static int ptdump_test_pud(unsigned long addr, unsigned long next, + pud_t *pud, struct mm_walk *walk) +{ +#if CONFIG_PGTABLE_LEVELS > 3 + if (pud == lm_alias(kasan_early_shadow_pud)) + return note_kasan_page_table(walk, addr); +#endif + return 0; +} + +static int ptdump_test_pmd(unsigned long addr, unsigned long next, + pmd_t *pmd, struct mm_walk *walk) +{ +#if CONFIG_PGTABLE_LEVELS > 2 + if (pmd == lm_alias(kasan_early_shadow_pmd)) + return note_kasan_page_table(walk, addr); +#endif + return 0; +} +#endif /* CONFIG_KASAN */ + +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; +} + +void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm) +{ + struct mm_walk walk = { + .mm = mm, + .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, +#ifdef CONFIG_KASAN + .test_p4d = ptdump_test_p4d, + .test_pud = ptdump_test_pud, + .test_pmd = ptdump_test_pmd, +#endif + .pte_hole = ptdump_hole, + .private = st + }; + const struct ptdump_range *range = st->range; + + down_read(&mm->mmap_sem); + while (range->start != range->end) { + walk_page_range(range->start, range->end, &walk); + range++; + } + up_read(&mm->mmap_sem); + + /* Flush out the last page */ + st->note_page(st, 0, 0, 0); +} -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-07-31 15:47 UTC|newest] Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-07-31 15:45 [PATCH v10 00/22] Generic page walk and ptdump Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 01/22] mm: Add generic p?d_leaf() macros Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 02/22] arc: mm: Add p?d_leaf() definitions Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 03/22] arm: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 04/22] arm64: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 05/22] mips: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 18:35 ` Paul Burton 2019-07-31 18:35 ` Paul Burton 2019-07-31 15:45 ` [PATCH v10 06/22] powerpc: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 07/22] riscv: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 08/22] s390: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 09/22] sparc: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 10/22] x86: " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 11/22] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 12/22] mm: pagewalk: Allow walking without vma Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 13/22] mm: pagewalk: Add test_p?d callbacks Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 14/22] mm: pagewalk: Add 'depth' parameter to pte_hole Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 15/22] x86: mm: Point to struct seq_file from struct pg_state Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 16/22] x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 17/22] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:45 ` [PATCH v10 18/22] x86: mm: Convert ptdump_walk_pgd_level_core() " Steven Price 2019-07-31 15:45 ` Steven Price 2019-07-31 15:46 ` Steven Price [this message] 2019-07-31 15:46 ` [PATCH v10 19/22] mm: Add generic ptdump Steven Price 2019-07-31 15:46 ` [PATCH v10 20/22] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price 2019-07-31 15:46 ` Steven Price 2019-08-06 23:58 ` Andrew Morton 2019-08-06 23:58 ` Andrew Morton 2019-08-07 12:58 ` Steven Price 2019-08-07 12:58 ` Steven Price 2019-08-07 20:16 ` Andrew Morton 2019-08-07 20:16 ` Andrew Morton 2019-07-31 15:46 ` [PATCH v10 21/22] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price 2019-07-31 15:46 ` Steven Price 2019-07-31 15:46 ` [PATCH v10 22/22] arm64: mm: Display non-present entries in ptdump Steven Price 2019-07-31 15:46 ` Steven Price
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