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 <ard.biesheuvel@linaro.org>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
new file mode 100644 (file)
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 ccfde23..f94b80e 100644 (file)
--- 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
@@ -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);