arm64: dump: Make ptdump debugfs a separate option

ptdump_register currently initializes a set of page table information and
registers debugfs. There are uses for the ptdump option without wanting the
debugfs options. Split this out to make it a separate option.

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

3 files changed, 38 insertions, 22 deletions

diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index 54bb209cae8e..e703fb9defad 100644
--- a/arch/arm64/mm/Makefile
+++ b/arch/arm64/mm/Makefile
@@ -3,7 +3,8 @@ obj-y				:= dma-mapping.o extable.o fault.o init.o \
 				   ioremap.o mmap.o pgd.o mmu.o \
 				   context.o proc.o pageattr.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
-obj-$(CONFIG_ARM64_PTDUMP)	+= dump.o
+obj-$(CONFIG_ARM64_PTDUMP_CORE)	+= dump.o
+obj-$(CONFIG_ARM64_PTDUMP_DEBUGFS)	+= ptdump_debugfs.o
 obj-$(CONFIG_NUMA)		+= numa.o
 
 obj-$(CONFIG_KASAN)		+= kasan_init.o
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index 9c3e75df2180..f0f0be74d8e7 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -304,9 +304,8 @@ static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
 	}
 }
 
-static int ptdump_show(struct seq_file *m, void *v)
+void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info)
 {
-	struct ptdump_info *info = m->private;
 	struct pg_state st = {
 		.seq = m,
 		.marker = info->markers,
@@ -315,33 +314,16 @@ static int ptdump_show(struct seq_file *m, void *v)
 	walk_pgd(&st, info->mm, info->base_addr);
 
 	note_page(&st, 0, 0, 0);
-	return 0;
 }
 
-static int ptdump_open(struct inode *inode, struct file *file)
+static void ptdump_initialize(void)
 {
-	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_register(struct ptdump_info *info, const char *name)
-{
-	struct dentry *pe;
 	unsigned i, j;
 
 	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
 		if (pg_level[i].bits)
 			for (j = 0; j < pg_level[i].num; j++)
 				pg_level[i].mask |= pg_level[i].bits[j].mask;
-
-	pe = debugfs_create_file(name, 0400, NULL, info, &ptdump_fops);
-	return pe ? 0 : -ENOMEM;
 }
 
 static struct ptdump_info kernel_ptdump_info = {
@@ -352,6 +334,8 @@ static struct ptdump_info kernel_ptdump_info = {
 
 static int ptdump_init(void)
 {
-	return ptdump_register(&kernel_ptdump_info, "kernel_page_tables");
+	ptdump_initialize();
+	return ptdump_debugfs_register(&kernel_ptdump_info,
+					"kernel_page_tables");
 }
 device_initcall(ptdump_init);
diff --git a/arch/arm64/mm/ptdump_debugfs.c b/arch/arm64/mm/ptdump_debugfs.c
new file mode 100644
index 000000000000..eee4d864350c
--- /dev/null
+++ b/arch/arm64/mm/ptdump_debugfs.c
@@ -0,0 +1,31 @@
+#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;
+
+}