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ARM: 8735/1: mm: dump: make page table dumping reusable

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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.
(4674fdb9f1 ("arm64: mm: dump: make page table dumping reusable"))
(4ddb9bf833 ("arm64: dump: Make ptdump debugfs a separate option"))

Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Jinbum Park 2017-12-12 01:41:09 +01:00 committed by Russell King
parent 6fbab054ec
commit 4fb69cc456
5 changed files with 106 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/arm/Kconfig.debug
View File

@ -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

35
arch/arm/include/asm/ptdump.h Normal file
View File

@ -0,0 +1,35 @@
/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2014 ARM Ltd. */
#ifndef __ASM_PTDUMP_H
#define __ASM_PTDUMP_H
#ifdef CONFIG_ARM_PTDUMP_CORE
#include <linux/mm_types.h>
#include <linux/seq_file.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;
};
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 */

3
arch/arm/mm/Makefile
View File

@ -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

69
arch/arm/mm/dump.c
View File

@ -21,11 +21,7 @@
#include <asm/fixmap.h>
#include <asm/memory.h>
#include <asm/pgtable.h>
struct addr_marker {
unsigned long start_address;
const char *name;
};
#include <asm/ptdump.h>
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);
}
}
}
void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info)
{
struct pg_state st = {
.seq = m,
.marker = info->markers,
};
walk_pgd(&st, info->mm, info->base_addr);
note_page(&st, 0, 0, 0, NULL);
}
static int ptdump_show(struct seq_file *m, void *v)
static void ptdump_initialize(void)
{
walk_pgd(m);
return 0;
}
static int ptdump_open(struct inode *inode, struct file *file)
{
return single_open(file, ptdump_show, 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)
{
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);

34
arch/arm/mm/ptdump_debugfs.c Normal file
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@ -0,0 +1,34 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <asm/ptdump.h>
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;
}