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Wed, 06 Dec 2017 02:24:11 -0800 (PST) Date: Wed, 6 Dec 2017 19:24:04 +0900 From: Jinbum Park To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [kernel-hardening][PATCH v4 1/3] arm: mm: dump: make page table dumping reusable Message-ID: <20171206102404.GA7030@pjb1027-Latitude-E5410> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171206_022434_066366_D928C8AF X-CRM114-Status: GOOD ( 20.66 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, vladimir.murzin@arm.com, keescook@chromium.org, arnd@arndb.de, gregkh@linuxfoundation.org, linux@armlinux.org.uk, labbott@redhat.com, afzal.mohd.ma@gmail.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP This patch refactors the arm page table dumping code, so multiple tables may be registered with the framework. This patch refers below commits of arm64. (4674fdb9f149 ("arm64: mm: dump: make page table dumping reusable")) (4ddb9bf83349 ("arm64: dump: Make ptdump debugfs a separate option")) Signed-off-by: Jinbum Park --- v4: No changes --- arch/arm/Kconfig.debug | 6 +++- arch/arm/include/asm/ptdump.h | 48 ++++++++++++++++++++++++++++++++ arch/arm/mm/Makefile | 3 +- arch/arm/mm/dump.c | 65 +++++++++++++++++++------------------------ arch/arm/mm/ptdump_debugfs.c | 34 ++++++++++++++++++++++ 5 files changed, 117 insertions(+), 39 deletions(-) create mode 100644 arch/arm/include/asm/ptdump.h create mode 100644 arch/arm/mm/ptdump_debugfs.c diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug index 17685e1..e7b94db 100644 --- a/arch/arm/Kconfig.debug +++ b/arch/arm/Kconfig.debug @@ -3,10 +3,14 @@ menu "Kernel hacking" source "lib/Kconfig.debug" -config ARM_PTDUMP +config ARM_PTDUMP_CORE + def_bool n + +config ARM_PTDUMP_DEBUGFS bool "Export kernel pagetable layout to userspace via debugfs" depends on DEBUG_KERNEL depends on MMU + select ARM_PTDUMP_CORE select DEBUG_FS ---help--- Say Y here if you want to show the kernel pagetable layout in a diff --git a/arch/arm/include/asm/ptdump.h b/arch/arm/include/asm/ptdump.h new file mode 100644 index 0000000..3a6c0b7 --- /dev/null +++ b/arch/arm/include/asm/ptdump.h @@ -0,0 +1,48 @@ +/* + * Copyright (C) 2014 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#ifndef __ASM_PTDUMP_H +#define __ASM_PTDUMP_H + +#ifdef CONFIG_ARM_PTDUMP_CORE + +#include +#include + +struct addr_marker { + unsigned long start_address; + char *name; +}; + +struct ptdump_info { + struct mm_struct *mm; + const struct addr_marker *markers; + unsigned long base_addr; +}; + +void ptdump_walk_pgd(struct seq_file *s, struct ptdump_info *info); +#ifdef CONFIG_ARM_PTDUMP_DEBUGFS +int ptdump_debugfs_register(struct ptdump_info *info, const char *name); +#else +static inline int ptdump_debugfs_register(struct ptdump_info *info, + const char *name) +{ + return 0; +} +#endif /* CONFIG_ARM_PTDUMP_DEBUGFS */ + +#endif /* CONFIG_ARM_PTDUMP_CORE */ + +#endif /* __ASM_PTDUMP_H */ diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile index 01bcc33..28be5f4 100644 --- a/arch/arm/mm/Makefile +++ b/arch/arm/mm/Makefile @@ -13,7 +13,8 @@ obj-y += nommu.o obj-$(CONFIG_ARM_MPU) += pmsa-v7.o endif -obj-$(CONFIG_ARM_PTDUMP) += dump.o +obj-$(CONFIG_ARM_PTDUMP_CORE) += dump.o +obj-$(CONFIG_ARM_PTDUMP_DEBUGFS) += ptdump_debugfs.o obj-$(CONFIG_MODULES) += proc-syms.o obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c index fc3b440..8dfe7c3 100644 --- a/arch/arm/mm/dump.c +++ b/arch/arm/mm/dump.c @@ -21,11 +21,7 @@ #include #include #include - -struct addr_marker { - unsigned long start_address; - const char *name; -}; +#include static struct addr_marker address_markers[] = { { MODULES_VADDR, "Modules" }, @@ -335,50 +331,36 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start) } } -static void walk_pgd(struct seq_file *m) +static void walk_pgd(struct pg_state *st, struct mm_struct *mm, + unsigned long start) { - pgd_t *pgd = swapper_pg_dir; - struct pg_state st; - unsigned long addr; + pgd_t *pgd = pgd_offset(mm, 0UL); unsigned i; - - memset(&st, 0, sizeof(st)); - st.seq = m; - st.marker = address_markers; + unsigned long addr; for (i = 0; i < PTRS_PER_PGD; i++, pgd++) { - addr = i * PGDIR_SIZE; + addr = start + i * PGDIR_SIZE; if (!pgd_none(*pgd)) { - walk_pud(&st, pgd, addr); + walk_pud(st, pgd, addr); } else { - note_page(&st, addr, 1, pgd_val(*pgd), NULL); + note_page(st, addr, 1, pgd_val(*pgd), NULL); } } - - note_page(&st, 0, 0, 0, NULL); } -static int ptdump_show(struct seq_file *m, void *v) +void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info) { - walk_pgd(m); - return 0; -} + struct pg_state st = { + .seq = m, + .marker = info->markers, + }; -static int ptdump_open(struct inode *inode, struct file *file) -{ - return single_open(file, ptdump_show, NULL); + walk_pgd(&st, info->mm, info->base_addr); + note_page(&st, 0, 0, 0, NULL); } -static const struct file_operations ptdump_fops = { - .open = ptdump_open, - .read = seq_read, - .llseek = seq_lseek, - .release = single_release, -}; - -static int ptdump_init(void) +static void ptdump_initialize(void) { - struct dentry *pe; unsigned i, j; for (i = 0; i < ARRAY_SIZE(pg_level); i++) @@ -387,9 +369,18 @@ static int ptdump_init(void) pg_level[i].mask |= pg_level[i].bits[j].mask; address_markers[2].start_address = VMALLOC_START; +} - pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, - &ptdump_fops); - return pe ? 0 : -ENOMEM; +static struct ptdump_info kernel_ptdump_info = { + .mm = &init_mm, + .markers = address_markers, + .base_addr = 0, +}; + +static int ptdump_init(void) +{ + ptdump_initialize(); + return ptdump_debugfs_register(&kernel_ptdump_info, + "kernel_page_tables"); } __initcall(ptdump_init); diff --git a/arch/arm/mm/ptdump_debugfs.c b/arch/arm/mm/ptdump_debugfs.c new file mode 100644 index 0000000..be8d87b --- /dev/null +++ b/arch/arm/mm/ptdump_debugfs.c @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +#include + +static int ptdump_show(struct seq_file *m, void *v) +{ + struct ptdump_info *info = m->private; + + ptdump_walk_pgd(m, info); + return 0; +} + +static int ptdump_open(struct inode *inode, struct file *file) +{ + return single_open(file, ptdump_show, inode->i_private); +} + +static const struct file_operations ptdump_fops = { + .open = ptdump_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +int ptdump_debugfs_register(struct ptdump_info *info, const char *name) +{ + struct dentry *pe; + + pe = debugfs_create_file(name, 0400, NULL, info, &ptdump_fops); + return pe ? 0 : -ENOMEM; + +}