[PATCH v2 4/6] arm64: mm: dump: make page table dumping reusable
From: mark.rutland@arm.com (Mark Rutland)
Date: 2016-05-13 12:56:07
Also in:
linux-efi
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
On Mon, Apr 25, 2016 at 12:07:57PM +0100, Will Deacon wrote:
Hi Ard, Mark, On Fri, Apr 22, 2016 at 06:48:06PM +0200, Ard Biesheuvel wrote:quoted
From: Mark Rutland <mark.rutland@arm.com> For debugging purposes, it would be nice if we could export page tables other than the swapper_pg_dir to userspace. To enable this, this patch refactors the arm64 page table dumping code such that multiple tables may be registered with the framework, and exported under debugfs. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Ard Biesheuvel <redacted> --- arch/arm64/include/asm/ptdump.h | 44 ++++++++++++++++++++ arch/arm64/mm/dump.c | 32 ++++++++------ 2 files changed, 64 insertions(+), 12 deletions(-)Could you reorder this with patch 3, please? I'm unsure about the benefit of the very specific string literal changes, but the ptdump stuff here certainly looks beneficial.
I'm sure this is far too late, but for posterity I've rebased patch 4 below atop of pathes 1 & 2 as queued in the arm64 for-next/core branch, without patch 3. It builds cleanly, and I've given it a spin on Juno. Will, I guess I should rebase and resend this after we hit v4.7-rc1? Thanks, Mark. ---->8----
From f17b52c0f004614027c356c848fd21308f4177c1 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com> Date: Fri, 22 Apr 2016 18:48:06 +0200 Subject: [PATCH] arm64: mm: dump: make page table dumping reusable For debugging purposes, it would be nice if we could export page tables other than the swapper_pg_dir to userspace. To enable this, this patch refactors the arm64 page table dumping code such that multiple tables may be registered with the framework, and exported under debugfs. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Ard Biesheuvel <redacted> --- arch/arm64/include/asm/ptdump.h | 44 +++++++++++++++++++++++++++++++++++++++++ arch/arm64/mm/dump.c | 32 +++++++++++++++++++----------- 2 files changed, 64 insertions(+), 12 deletions(-) create mode 100644 arch/arm64/include/asm/ptdump.h
diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
new file mode 100644
index 0000000..07b8ed0
--- /dev/null
+++ b/arch/arm64/include/asm/ptdump.h@@ -0,0 +1,44 @@ +/* + * 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 <http://www.gnu.org/licenses/>. + */ +#ifndef __ASM_PTDUMP_H +#define __ASM_PTDUMP_H + +#ifdef CONFIG_ARM64_PTDUMP + +#include <linux/mm_types.h> + +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; + unsigned long max_addr; +}; + +int ptdump_register(struct ptdump_info *info, const char *name); + +#else +static inline int ptdump_register(struct ptdump_info *info, const char *name) +{ + return 0; +} +#endif /* CONFIG_ARM64_PTDUMP */ + +#endif /* __ASM_PTDUMP_H */
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index 8404190..a56a7ad 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c@@ -27,11 +27,7 @@ #include <asm/memory.h> #include <asm/pgtable.h> #include <asm/pgtable-hwdef.h> - -struct addr_marker { - unsigned long start_address; - const char *name; -}; +#include <asm/ptdump.h> static const struct addr_marker address_markers[] = { #ifdef CONFIG_KASAN
@@ -284,7 +280,8 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start) } } -static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start) +static void walk_pgd(struct pg_state *st, struct mm_struct *mm, + unsigned long start) { pgd_t *pgd = pgd_offset(mm, 0UL); unsigned i;
@@ -303,12 +300,13 @@ static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long st static int ptdump_show(struct seq_file *m, void *v) { + struct ptdump_info *info = m->private; struct pg_state st = { .seq = m, - .marker = address_markers, + .marker = info->markers, }; - walk_pgd(&st, &init_mm, VA_START); + walk_pgd(&st, info->mm, info->base_addr); note_page(&st, 0, 0, 0); return 0;
@@ -316,7 +314,7 @@ static int ptdump_show(struct seq_file *m, void *v) static int ptdump_open(struct inode *inode, struct file *file) { - return single_open(file, ptdump_show, NULL); + return single_open(file, ptdump_show, inode->i_private); } static const struct file_operations ptdump_fops = {
@@ -326,7 +324,7 @@ static const struct file_operations ptdump_fops = { .release = single_release, }; -static int ptdump_init(void) +int ptdump_register(struct ptdump_info *info, const char *name) { struct dentry *pe; unsigned i, j;
@@ -336,8 +334,18 @@ static int ptdump_init(void) for (j = 0; j < pg_level[i].num; j++) pg_level[i].mask |= pg_level[i].bits[j].mask; - pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, - &ptdump_fops); + pe = debugfs_create_file(name, 0400, NULL, info, &ptdump_fops); return pe ? 0 : -ENOMEM; } + +static struct ptdump_info kernel_ptdump_info = { + .mm = &init_mm, + .markers = address_markers, + .base_addr = VA_START, +}; + +static int ptdump_init(void) +{ + return ptdump_register(&kernel_ptdump_info, "kernel_page_tables"); +} device_initcall(ptdump_init);
--
1.9.1