Commit 8609d1b5 authored by Kees Cook's avatar Kees Cook Committed by Ingo Molnar
Browse files

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: default avatarKees Cook <keescook@chromium.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20151120010755.GA9060@www.outflux.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1ec21837

arch/x86/Kconfig.debug

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/mm/debug_pagetables.c

0 → 100644
+46 −0
Original line number Diff line number Diff line 
#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@linux.intel.com>");

MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");

arch/x86/mm/dump_pagetables.c

+2 −32
Original line number Diff line number Diff line
@@ -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;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE