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: Kees Cook <keesc...@chromium.org>
Reviewed-by: Mark Rutland <mark.rutl...@arm.com>
Tested-by: Mark Rutland <mark.rutl...@arm.com>
Signed-off-by: Laura Abbott <labb...@redhat.com>
---
v3: Minor header guard fixup.

Mark Rutland pointed out that this needs to be reviewed by the EFI maintainers
so I'm explicitly adding appropriate people/lists.
---
 arch/arm64/Kconfig.debug           |  6 +++++-
 arch/arm64/include/asm/ptdump.h    | 15 +++++++++------
 arch/arm64/mm/Makefile             |  3 ++-
 arch/arm64/mm/dump.c               | 26 +++++---------------------
 arch/arm64/mm/ptdump_debugfs.c     | 31 +++++++++++++++++++++++++++++++
 drivers/firmware/efi/arm-runtime.c |  4 ++--
 6 files changed, 54 insertions(+), 31 deletions(-)
 create mode 100644 arch/arm64/mm/ptdump_debugfs.c

diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index b661fe7..21a5b74 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -2,9 +2,13 @@ menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
-config ARM64_PTDUMP
+config ARM64_PTDUMP_CORE
+       def_bool n
+
+config ARM64_PTDUMP_DEBUGFS
        bool "Export kernel pagetable layout to userspace via debugfs"
        depends on DEBUG_KERNEL
+       select ARM64_PTDUMP_CORE
        select DEBUG_FS
         help
          Say Y here if you want to show the kernel pagetable layout in a
diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
index 07b8ed0..16335da 100644
--- a/arch/arm64/include/asm/ptdump.h
+++ b/arch/arm64/include/asm/ptdump.h
@@ -16,9 +16,10 @@
 #ifndef __ASM_PTDUMP_H
 #define __ASM_PTDUMP_H
 
-#ifdef CONFIG_ARM64_PTDUMP
+#ifdef CONFIG_ARM64_PTDUMP_CORE
 
 #include <linux/mm_types.h>
+#include <linux/seq_file.h>
 
 struct addr_marker {
        unsigned long start_address;
@@ -32,13 +33,15 @@ struct ptdump_info {
        unsigned long                   max_addr;
 };
 
-int ptdump_register(struct ptdump_info *info, const char *name);
-
+void ptdump_walk_pgd(struct seq_file *s, struct ptdump_info *info);
+#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
+int ptdump_debugfs_register(struct ptdump_info *info, const char *name);
 #else
-static inline int ptdump_register(struct ptdump_info *info, const char *name)
+static inline int ptdump_debugfs_register(struct ptdump_info *info,
+                                       const char *name)
 {
        return 0;
 }
-#endif /* CONFIG_ARM64_PTDUMP */
-
+#endif
+#endif /* CONFIG_ARM64_PTDUMP_CORE */
 #endif /* __ASM_PTDUMP_H */
diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index 54bb209..e703fb9 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 9c3e75d..f0f0be7 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 0000000..eee4d86
--- /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;
+
+}
diff --git a/drivers/firmware/efi/arm-runtime.c 
b/drivers/firmware/efi/arm-runtime.c
index 7c75a8d..349dc3e 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -39,7 +39,7 @@ static struct mm_struct efi_mm = {
        .mmlist                 = LIST_HEAD_INIT(efi_mm.mmlist),
 };
 
-#ifdef CONFIG_ARM64_PTDUMP
+#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
 #include <asm/ptdump.h>
 
 static struct ptdump_info efi_ptdump_info = {
@@ -53,7 +53,7 @@ static struct ptdump_info efi_ptdump_info = {
 
 static int __init ptdump_init(void)
 {
-       return ptdump_register(&efi_ptdump_info, "efi_page_tables");
+       return ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
 }
 device_initcall(ptdump_init);
 
-- 
2.7.4

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