https://github.com/torvalds/linux
Tip revision: 6fbc7275c7a9ba97877050335f290341a1fd8dbf authored by Linus Torvalds on 30 June 2019, 03:25:36 UTC
Linux 5.2-rc7
Linux 5.2-rc7
Tip revision: 6fbc727
debug_pagetables.c
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/debugfs.h>
#include <linux/efi.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_debugfs(m, NULL, false);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ptdump);
static int ptdump_curknl_show(struct seq_file *m, void *v)
{
if (current->mm->pgd) {
down_read(¤t->mm->mmap_sem);
ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false);
up_read(¤t->mm->mmap_sem);
}
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ptdump_curknl);
#ifdef CONFIG_PAGE_TABLE_ISOLATION
static struct dentry *pe_curusr;
static int ptdump_curusr_show(struct seq_file *m, void *v)
{
if (current->mm->pgd) {
down_read(¤t->mm->mmap_sem);
ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true);
up_read(¤t->mm->mmap_sem);
}
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ptdump_curusr);
#endif
#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
static struct dentry *pe_efi;
static int ptdump_efi_show(struct seq_file *m, void *v)
{
if (efi_mm.pgd)
ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ptdump_efi);
#endif
static struct dentry *dir, *pe_knl, *pe_curknl;
static int __init pt_dump_debug_init(void)
{
dir = debugfs_create_dir("page_tables", NULL);
if (!dir)
return -ENOMEM;
pe_knl = debugfs_create_file("kernel", 0400, dir, NULL,
&ptdump_fops);
if (!pe_knl)
goto err;
pe_curknl = debugfs_create_file("current_kernel", 0400,
dir, NULL, &ptdump_curknl_fops);
if (!pe_curknl)
goto err;
#ifdef CONFIG_PAGE_TABLE_ISOLATION
pe_curusr = debugfs_create_file("current_user", 0400,
dir, NULL, &ptdump_curusr_fops);
if (!pe_curusr)
goto err;
#endif
#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
pe_efi = debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops);
if (!pe_efi)
goto err;
#endif
return 0;
err:
debugfs_remove_recursive(dir);
return -ENOMEM;
}
static void __exit pt_dump_debug_exit(void)
{
debugfs_remove_recursive(dir);
}
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");