diff mbox

[v2,4/6] arm64: mm: dump: make page table dumping reusable

Message ID 1461343688-8552-5-git-send-email-ard.biesheuvel@linaro.org
State New
Headers show

Commit Message

Ard Biesheuvel April 22, 2016, 4:48 p.m. UTC 
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 <ard.biesheuvel@linaro.org>

---
 arch/arm64/include/asm/ptdump.h | 44 ++++++++++++++++++++
 arch/arm64/mm/dump.c            | 32 ++++++++------
 2 files changed, 64 insertions(+), 12 deletions(-)

-- 
2.7.4


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Comments

Will Deacon April 25, 2016, 11:07 a.m. UTC | #1 
Hi Ard, Mark,

On Fri, Apr 22, 2016 at 06:48:06PM +0200, Ard Biesheuvel wrote:
> 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 <ard.biesheuvel@linaro.org>

> ---

>  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 can queue the first two patches as-is.

Thanks.

Will

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diff mbox

Patch

diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
new file mode 100644
index 000000000000..fe82d693638a
--- /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[32];
+};
+
+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 024f803e2fb4..73d7227d1403 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;
-	char name[32];
-};
+#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);