Commit-ID: 8609d1b5daa36350e020e737946c40887af1743a
Gitweb: http://git.kernel.org/tip/8609d1b5daa36350e020e737946c40887af1743a
Author: Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate: Thu, 19 Nov 2015 17:07:55 -0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 23 Nov 2015 10:50:13 +0100
x86/mm: Turn CONFIG_X86_PTDUMP into a module
Being able to examine page tables is handy, so make this a
module that can be loaded as needed.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephen Smalley <sds@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Vladimir Murzin <vladimir.murzin@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Link: http://lkml.kernel.org/r/20151120010755.GA9060@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/Kconfig.debug | 2 +-
arch/x86/mm/Makefile | 1 +
arch/x86/mm/debug_pagetables.c | 46 ++++++++++++++++++++++++++++++++++++++++++
arch/x86/mm/dump_pagetables.c | 34 ++-----------------------------
4 files changed, 50 insertions(+), 33 deletions(-)
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 137dfa9..110253c 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -69,7 +69,7 @@ config X86_PTDUMP_CORE
def_bool n
config X86_PTDUMP
- bool "Export kernel pagetable layout to userspace via debugfs"
+ tristate "Export kernel pagetable layout to userspace via debugfs"
depends on DEBUG_KERNEL
select DEBUG_FS
select X86_PTDUMP_CORE
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 65c47fd..f9d38a4 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_X86_32) += pgtable_32.o iomap_32.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_X86_PTDUMP_CORE) += dump_pagetables.o
+obj-$(CONFIG_X86_PTDUMP) += debug_pagetables.o
obj-$(CONFIG_HIGHMEM) += highmem_32.o
diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
new file mode 100644
index 0000000..b35ee86
--- /dev/null
+++ b/arch/x86/mm/debug_pagetables.c
@@ -0,0 +1,46 @@
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <asm/pgtable.h>
+
+static int ptdump_show(struct seq_file *m, void *v)
+{
+ ptdump_walk_pgd_level(m, NULL);
+ return 0;
+}
+
+static int ptdump_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, ptdump_show, NULL);
+}
+
+static const struct file_operations ptdump_fops = {
+ .owner = THIS_MODULE,
+ .open = ptdump_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static struct dentry *pe;
+
+static int __init pt_dump_debug_init(void)
+{
+ pe = debugfs_create_file("kernel_page_tables", 0600, NULL, NULL,
+ &ptdump_fops);
+ if (!pe)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __exit pt_dump_debug_exit(void)
+{
+ debugfs_remove_recursive(pe);
+}
+
+module_init(pt_dump_debug_init);
+module_exit(pt_dump_debug_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index a035c2a..90a1dc0 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -426,38 +426,15 @@ void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
{
ptdump_walk_pgd_level_core(m, pgd, false);
}
+EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level);
void ptdump_walk_pgd_level_checkwx(void)
{
ptdump_walk_pgd_level_core(NULL, NULL, true);
}
-#ifdef CONFIG_X86_PTDUMP
-static int ptdump_show(struct seq_file *m, void *v)
+static int __init pt_dump_init(void)
{
- ptdump_walk_pgd_level(m, NULL);
- return 0;
-}
-
-static int ptdump_open(struct inode *inode, struct file *filp)
-{
- return single_open(filp, ptdump_show, NULL);
-}
-
-static const struct file_operations ptdump_fops = {
- .open = ptdump_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
-#endif
-
-static int pt_dump_init(void)
-{
-#ifdef CONFIG_X86_PTDUMP
- struct dentry *pe;
-#endif
-
#ifdef CONFIG_X86_32
/* Not a compile-time constant on x86-32 */
address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
@@ -468,13 +445,6 @@ static int pt_dump_init(void)
address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
#endif
-#ifdef CONFIG_X86_PTDUMP
- pe = debugfs_create_file("kernel_page_tables", 0600, NULL, NULL,
- &ptdump_fops);
- if (!pe)
- return -ENOMEM;
-#endif
-
return 0;
}
--
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