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Commit 4674fdb9 authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
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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: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 0e455d8e

arch/arm64/include/asm/ptdump.h

0 → 100644
+44 −0
Original line number Diff line number Diff line 
/*

 * 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 */

arch/arm64/mm/dump.c

+20 −12
Original line number Diff line number Diff line
@@ -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
@@ -290,7 +286,8 @@ 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;
@@ -309,12 +306,13 @@ 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;
@@ -322,7 +320,7 @@ 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 = {
@@ -332,7 +330,7 @@ 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;
@@ -342,8 +340,18 @@ 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);