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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/x86/mm/debug_pagetables.c
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// SPDX-License-Identifier: GPL-2.0-only

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#include <linux/debugfs.h>

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#include <linux/efi.h>

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#include <linux/module.h>

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#include <linux/seq_file.h>

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#include <linux/pgtable.h>

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static int ptdump_show(struct seq_file *m, void *v)

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{

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	ptdump_walk_pgd_level_debugfs(m, &init_mm, false);

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	return 0;

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}

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DEFINE_SHOW_ATTRIBUTE(ptdump);

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static int ptdump_curknl_show(struct seq_file *m, void *v)

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{

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	if (current->mm->pgd)

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		ptdump_walk_pgd_level_debugfs(m, current->mm, false);

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	return 0;

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}

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DEFINE_SHOW_ATTRIBUTE(ptdump_curknl);

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#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION

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static int ptdump_curusr_show(struct seq_file *m, void *v)

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{

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	if (current->mm->pgd)

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		ptdump_walk_pgd_level_debugfs(m, current->mm, true);

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	return 0;

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}

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DEFINE_SHOW_ATTRIBUTE(ptdump_curusr);

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#endif

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#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)

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static int ptdump_efi_show(struct seq_file *m, void *v)

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{

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	if (efi_mm.pgd)

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		ptdump_walk_pgd_level_debugfs(m, &efi_mm, false);

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	return 0;

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}

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DEFINE_SHOW_ATTRIBUTE(ptdump_efi);

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#endif

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static struct dentry *dir;

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static int __init pt_dump_debug_init(void)

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{

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	dir = debugfs_create_dir("page_tables", NULL);

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	debugfs_create_file("kernel", 0400, dir, NULL, &ptdump_fops);

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	debugfs_create_file("current_kernel", 0400, dir, NULL,

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			    &ptdump_curknl_fops);

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#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION

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	debugfs_create_file("current_user", 0400, dir, NULL,

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			    &ptdump_curusr_fops);

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#endif

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#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)

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	debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops);

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#endif

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	return 0;

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}

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static void __exit pt_dump_debug_exit(void)

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{

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	debugfs_remove_recursive(dir);

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}

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module_init(pt_dump_debug_init);

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module_exit(pt_dump_debug_exit);

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MODULE_AUTHOR("Arjan van de Ven <[email protected]>");

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

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