[linux-2.6-block.git] / arch / powerpc / mm / dump_linuxpagetables.c

/*
 * Copyright 2016, Rashmica Gupta, IBM Corp.
 *
 * This traverses the kernel pagetables and dumps the
 * information about the used sections of memory to
 * /sys/kernel/debug/kernel_pagetables.
 *
 * Derived from the arm64 implementation:
 * Copyright (c) 2014, The Linux Foundation, Laura Abbott.
 * (C) Copyright 2008 Intel Corporation, Arjan van de Ven.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/hugetlb.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
#include <linux/const.h>
#include <asm/page.h>
#include <asm/pgalloc.h>

#include "dump_linuxpagetables.h"

#ifdef CONFIG_PPC32
#define KERN_VIRT_START	0
#endif

/*
 * To visualise what is happening,
 *
 *  - PTRS_PER_P** = how many entries there are in the corresponding P**
 *  - P**_SHIFT = how many bits of the address we use to index into the
 * corresponding P**
 *  - P**_SIZE is how much memory we can access through the table - not the
 * size of the table itself.
 * P**={PGD, PUD, PMD, PTE}
 *
 *
 * Each entry of the PGD points to a PUD. Each entry of a PUD points to a
 * PMD. Each entry of a PMD points to a PTE. And every PTE entry points to
 * a page.
 *
 * In the case where there are only 3 levels, the PUD is folded into the
 * PGD: every PUD has only one entry which points to the PMD.
 *
 * The page dumper groups page table entries of the same type into a single
 * description. It uses pg_state to track the range information while
 * iterating over the PTE entries. When the continuity is broken it then
 * dumps out a description of the range - ie PTEs that are virtually contiguous
 * with the same PTE flags are chunked together. This is to make it clear how
 * different areas of the kernel virtual memory are used.
 *
 */
struct pg_state {
	struct seq_file *seq;
	const struct addr_marker *marker;
	unsigned long start_address;
	unsigned long start_pa;
	unsigned long last_pa;
	unsigned int level;
	u64 current_flags;
};

struct addr_marker {
	unsigned long start_address;
	const char *name;
};

static struct addr_marker address_markers[] = {
	{ 0,	"Start of kernel VM" },
	{ 0,	"vmalloc() Area" },
	{ 0,	"vmalloc() End" },
#ifdef CONFIG_PPC64
	{ 0,	"isa I/O start" },
	{ 0,	"isa I/O end" },
	{ 0,	"phb I/O start" },
	{ 0,	"phb I/O end" },
	{ 0,	"I/O remap start" },
	{ 0,	"I/O remap end" },
	{ 0,	"vmemmap start" },
#else
	{ 0,	"Early I/O remap start" },
	{ 0,	"Early I/O remap end" },
#ifdef CONFIG_NOT_COHERENT_CACHE
	{ 0,	"Consistent mem start" },
	{ 0,	"Consistent mem end" },
#endif
#ifdef CONFIG_HIGHMEM
	{ 0,	"Highmem PTEs start" },
	{ 0,	"Highmem PTEs end" },
#endif
	{ 0,	"Fixmap start" },
	{ 0,	"Fixmap end" },
#endif
	{ -1,	NULL },
};

static void dump_flag_info(struct pg_state *st, const struct flag_info
		*flag, u64 pte, int num)
{
	unsigned int i;

	for (i = 0; i < num; i++, flag++) {
		const char *s = NULL;
		u64 val;

		/* flag not defined so don't check it */
		if (flag->mask == 0)
			continue;
		/* Some 'flags' are actually values */
		if (flag->is_val) {
			val = pte & flag->val;
			if (flag->shift)
				val = val >> flag->shift;
			seq_printf(st->seq, "  %s:%llx", flag->set, val);
		} else {
			if ((pte & flag->mask) == flag->val)
				s = flag->set;
			else
				s = flag->clear;
			if (s)
				seq_printf(st->seq, "  %s", s);
		}
		st->current_flags &= ~flag->mask;
	}
	if (st->current_flags != 0)
		seq_printf(st->seq, "  unknown flags:%llx", st->current_flags);
}

static void dump_addr(struct pg_state *st, unsigned long addr)
{
	static const char units[] = "KMGTPE";
	const char *unit = units;
	unsigned long delta;

#ifdef CONFIG_PPC64
	seq_printf(st->seq, "0x%016lx-0x%016lx ", st->start_address, addr-1);
	seq_printf(st->seq, "0x%016lx ", st->start_pa);
#else
	seq_printf(st->seq, "0x%08lx-0x%08lx ", st->start_address, addr - 1);
	seq_printf(st->seq, "0x%08lx ", st->start_pa);
#endif

	delta = (addr - st->start_address) >> 10;
	/* Work out what appropriate unit to use */
	while (!(delta & 1023) && unit[1]) {
		delta >>= 10;
		unit++;
	}
	seq_printf(st->seq, "%9lu%c", delta, *unit);

}

static void note_page(struct pg_state *st, unsigned long addr,
	       unsigned int level, u64 val)
{
	u64 flag = val & pg_level[level].mask;
	u64 pa = val & PTE_RPN_MASK;

	/* At first no level is set */
	if (!st->level) {
		st->level = level;
		st->current_flags = flag;
		st->start_address = addr;
		st->start_pa = pa;
		st->last_pa = pa;
		seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
	/*
	 * Dump the section of virtual memory when:
	 *   - the PTE flags from one entry to the next differs.
	 *   - we change levels in the tree.
	 *   - the address is in a different section of memory and is thus
	 *   used for a different purpose, regardless of the flags.
	 *   - the pa of this page is not adjacent to the last inspected page
	 */
	} else if (flag != st->current_flags || level != st->level ||
		   addr >= st->marker[1].start_address ||
		   pa != st->last_pa + PAGE_SIZE) {

		/* Check the PTE flags */
		if (st->current_flags) {
			dump_addr(st, addr);

			/* Dump all the flags */
			if (pg_level[st->level].flag)
				dump_flag_info(st, pg_level[st->level].flag,
					  st->current_flags,
					  pg_level[st->level].num);

			seq_putc(st->seq, '\n');
		}

		/*
		 * Address indicates we have passed the end of the
		 * current section of virtual memory
		 */
		while (addr >= st->marker[1].start_address) {
			st->marker++;
			seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
		}
		st->start_address = addr;
		st->start_pa = pa;
		st->last_pa = pa;
		st->current_flags = flag;
		st->level = level;
	} else {
		st->last_pa = pa;
	}
}

static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
{
	pte_t *pte = pte_offset_kernel(pmd, 0);
	unsigned long addr;
	unsigned int i;

	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
		addr = start + i * PAGE_SIZE;
		note_page(st, addr, 4, pte_val(*pte));

	}
}

static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
{
	pmd_t *pmd = pmd_offset(pud, 0);
	unsigned long addr;
	unsigned int i;

	for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
		addr = start + i * PMD_SIZE;
		if (!pmd_none(*pmd) && !pmd_huge(*pmd))
			/* pmd exists */
			walk_pte(st, pmd, addr);
		else
			note_page(st, addr, 3, pmd_val(*pmd));
	}
}

static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
{
	pud_t *pud = pud_offset(pgd, 0);
	unsigned long addr;
	unsigned int i;

	for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
		addr = start + i * PUD_SIZE;
		if (!pud_none(*pud) && !pud_huge(*pud))
			/* pud exists */
			walk_pmd(st, pud, addr);
		else
			note_page(st, addr, 2, pud_val(*pud));
	}
}

static void walk_pagetables(struct pg_state *st)
{
	pgd_t *pgd = pgd_offset_k(0UL);
	unsigned int i;
	unsigned long addr;

	/*
	 * Traverse the linux pagetable structure and dump pages that are in
	 * the hash pagetable.
	 */
	for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
		addr = KERN_VIRT_START + i * PGDIR_SIZE;
		if (!pgd_none(*pgd) && !pgd_huge(*pgd))
			/* pgd exists */
			walk_pud(st, pgd, addr);
		else
			note_page(st, addr, 1, pgd_val(*pgd));
	}
}

static void populate_markers(void)
{
	int i = 0;

	address_markers[i++].start_address = PAGE_OFFSET;
	address_markers[i++].start_address = VMALLOC_START;
	address_markers[i++].start_address = VMALLOC_END;
#ifdef CONFIG_PPC64
	address_markers[i++].start_address = ISA_IO_BASE;
	address_markers[i++].start_address = ISA_IO_END;
	address_markers[i++].start_address = PHB_IO_BASE;
	address_markers[i++].start_address = PHB_IO_END;
	address_markers[i++].start_address = IOREMAP_BASE;
	address_markers[i++].start_address = IOREMAP_END;
#ifdef CONFIG_PPC_BOOK3S_64
	address_markers[i++].start_address =  H_VMEMMAP_BASE;
#else
	address_markers[i++].start_address =  VMEMMAP_BASE;
#endif
#else /* !CONFIG_PPC64 */
	address_markers[i++].start_address = ioremap_bot;
	address_markers[i++].start_address = IOREMAP_TOP;
#ifdef CONFIG_NOT_COHERENT_CACHE
	address_markers[i++].start_address = IOREMAP_TOP;
	address_markers[i++].start_address = IOREMAP_TOP +
					     CONFIG_CONSISTENT_SIZE;
#endif
#ifdef CONFIG_HIGHMEM
	address_markers[i++].start_address = PKMAP_BASE;
	address_markers[i++].start_address = PKMAP_ADDR(LAST_PKMAP);
#endif
	address_markers[i++].start_address = FIXADDR_START;
	address_markers[i++].start_address = FIXADDR_TOP;
#endif /* CONFIG_PPC64 */
}

static int ptdump_show(struct seq_file *m, void *v)
{
	struct pg_state st = {
		.seq = m,
		.start_address = KERN_VIRT_START,
		.marker = address_markers,
	};
	/* Traverse kernel page tables */
	walk_pagetables(&st);
	note_page(&st, 0, 0, 0);
	return 0;
}


static int ptdump_open(struct inode *inode, struct file *file)
{
	return single_open(file, ptdump_show, NULL);
}

static const struct file_operations ptdump_fops = {
	.open		= ptdump_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static void build_pgtable_complete_mask(void)
{
	unsigned int i, j;

	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
		if (pg_level[i].flag)
			for (j = 0; j < pg_level[i].num; j++)
				pg_level[i].mask |= pg_level[i].flag[j].mask;
}

static int ptdump_init(void)
{
	struct dentry *debugfs_file;

	populate_markers();
	build_pgtable_complete_mask();
	debugfs_file = debugfs_create_file("kernel_page_tables", 0400, NULL,
			NULL, &ptdump_fops);
	return debugfs_file ? 0 : -ENOMEM;
}
device_initcall(ptdump_init);
Commit	Line	Data
8eb07b18 RG	1	/*
	2	* Copyright 2016, Rashmica Gupta, IBM Corp.
	3	*
	4	* This traverses the kernel pagetables and dumps the
	5	* information about the used sections of memory to
	6	* /sys/kernel/debug/kernel_pagetables.
	7	*
	8	* Derived from the arm64 implementation:
	9	* Copyright (c) 2014, The Linux Foundation, Laura Abbott.
	10	* (C) Copyright 2008 Intel Corporation, Arjan van de Ven.
	11	*
	12	* This program is free software; you can redistribute it and/or
	13	* modify it under the terms of the GNU General Public License
	14	* as published by the Free Software Foundation; version 2
	15	* of the License.
	16	*/
	17	#include <linux/debugfs.h>
	18	#include <linux/fs.h>
bfb9956a	19	#include <linux/hugetlb.h>
8eb07b18 RG	20	#include <linux/io.h>
	21	#include <linux/mm.h>
	22	#include <linux/sched.h>
	23	#include <linux/seq_file.h>
	24	#include <asm/fixmap.h>
	25	#include <asm/pgtable.h>
	26	#include <linux/const.h>
	27	#include <asm/page.h>
	28	#include <asm/pgalloc.h>
	29
97026b5a CL	30	#include "dump_linuxpagetables.h"
97026b5a CL	31
6c01bbd2 CL	32	#ifdef CONFIG_PPC32
	33	#define KERN_VIRT_START 0
	34	#endif
	35
8eb07b18 RG	36	/*
	37	* To visualise what is happening,
	38	*
	39	* - PTRS_PER_P = how many entries there are in the corresponding P
	40	* - P**_SHIFT = how many bits of the address we use to index into the
	41	* corresponding P**
	42	* - P**_SIZE is how much memory we can access through the table - not the
	43	* size of the table itself.
	44	* P**={PGD, PUD, PMD, PTE}
	45	*
	46	*
	47	* Each entry of the PGD points to a PUD. Each entry of a PUD points to a
	48	* PMD. Each entry of a PMD points to a PTE. And every PTE entry points to
	49	* a page.
	50	*
	51	* In the case where there are only 3 levels, the PUD is folded into the
	52	* PGD: every PUD has only one entry which points to the PMD.
	53	*
	54	* The page dumper groups page table entries of the same type into a single
	55	* description. It uses pg_state to track the range information while
	56	* iterating over the PTE entries. When the continuity is broken it then
	57	* dumps out a description of the range - ie PTEs that are virtually contiguous
	58	* with the same PTE flags are chunked together. This is to make it clear how
	59	* different areas of the kernel virtual memory are used.
	60	*
	61	*/
	62	struct pg_state {
	63	struct seq_file *seq;
	64	const struct addr_marker *marker;
	65	unsigned long start_address;
aaa22952 OH	66	unsigned long start_pa;
aaa22952 OH	67	unsigned long last_pa;
8eb07b18 RG	68	unsigned int level;
	69	u64 current_flags;
	70	};
	71
	72	struct addr_marker {
	73	unsigned long start_address;
	74	const char *name;
	75	};
	76
	77	static struct addr_marker address_markers[] = {
	78	{ 0, "Start of kernel VM" },
	79	{ 0, "vmalloc() Area" },
	80	{ 0, "vmalloc() End" },
6c01bbd2	81	#ifdef CONFIG_PPC64
8eb07b18 RG	82	{ 0, "isa I/O start" },
	83	{ 0, "isa I/O end" },
	84	{ 0, "phb I/O start" },
	85	{ 0, "phb I/O end" },
	86	{ 0, "I/O remap start" },
	87	{ 0, "I/O remap end" },
	88	{ 0, "vmemmap start" },
6c01bbd2 CL	89	#else
	90	{ 0, "Early I/O remap start" },
	91	{ 0, "Early I/O remap end" },
	92	#ifdef CONFIG_NOT_COHERENT_CACHE
	93	{ 0, "Consistent mem start" },
	94	{ 0, "Consistent mem end" },
	95	#endif
	96	#ifdef CONFIG_HIGHMEM
	97	{ 0, "Highmem PTEs start" },
	98	{ 0, "Highmem PTEs end" },
	99	#endif
	100	{ 0, "Fixmap start" },
	101	{ 0, "Fixmap end" },
	102	#endif
8eb07b18 RG	103	{ -1, NULL },
	104	};
	105
8eb07b18 RG	106	static void dump_flag_info(struct pg_state *st, const struct flag_info
	107	*flag, u64 pte, int num)
	108	{
	109	unsigned int i;
	110
	111	for (i = 0; i < num; i++, flag++) {
	112	const char *s = NULL;
	113	u64 val;
	114
	115	/* flag not defined so don't check it */
	116	if (flag->mask == 0)
	117	continue;
	118	/* Some 'flags' are actually values */
	119	if (flag->is_val) {
	120	val = pte & flag->val;
	121	if (flag->shift)
	122	val = val >> flag->shift;
	123	seq_printf(st->seq, " %s:%llx", flag->set, val);
	124	} else {
	125	if ((pte & flag->mask) == flag->val)
	126	s = flag->set;
	127	else
	128	s = flag->clear;
	129	if (s)
	130	seq_printf(st->seq, " %s", s);
	131	}
	132	st->current_flags &= ~flag->mask;
	133	}
	134	if (st->current_flags != 0)
	135	seq_printf(st->seq, " unknown flags:%llx", st->current_flags);
	136	}
	137
	138	static void dump_addr(struct pg_state *st, unsigned long addr)
	139	{
	140	static const char units[] = "KMGTPE";
	141	const char *unit = units;
	142	unsigned long delta;
	143
78a18dbf	144	#ifdef CONFIG_PPC64
aaa22952 OH	145	seq_printf(st->seq, "0x%016lx-0x%016lx ", st->start_address, addr-1);
aaa22952 OH	146	seq_printf(st->seq, "0x%016lx ", st->start_pa);
78a18dbf CL	147	#else
	148	seq_printf(st->seq, "0x%08lx-0x%08lx ", st->start_address, addr - 1);
	149	seq_printf(st->seq, "0x%08lx ", st->start_pa);
	150	#endif
aaa22952	151
8eb07b18 RG	152	delta = (addr - st->start_address) >> 10;
	153	/* Work out what appropriate unit to use */
	154	while (!(delta & 1023) && unit[1]) {
	155	delta >>= 10;
	156	unit++;
	157	}
	158	seq_printf(st->seq, "%9lu%c", delta, *unit);
	159
	160	}
	161
	162	static void note_page(struct pg_state *st, unsigned long addr,
	163	unsigned int level, u64 val)
	164	{
	165	u64 flag = val & pg_level[level].mask;
aaa22952 OH	166	u64 pa = val & PTE_RPN_MASK;
aaa22952 OH	167
8eb07b18 RG	168	/* At first no level is set */
	169	if (!st->level) {
	170	st->level = level;
	171	st->current_flags = flag;
	172	st->start_address = addr;
aaa22952 OH	173	st->start_pa = pa;
aaa22952 OH	174	st->last_pa = pa;
8eb07b18 RG	175	seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
	176	/*
	177	* Dump the section of virtual memory when:
	178	* - the PTE flags from one entry to the next differs.
	179	* - we change levels in the tree.
	180	* - the address is in a different section of memory and is thus
	181	* used for a different purpose, regardless of the flags.
aaa22952	182	* - the pa of this page is not adjacent to the last inspected page
8eb07b18 RG	183	*/
8eb07b18 RG	184	} else if (flag != st->current_flags \|\| level != st->level \|\|
aaa22952 OH	185	addr >= st->marker[1].start_address \|\|
aaa22952 OH	186	pa != st->last_pa + PAGE_SIZE) {
8eb07b18 RG	187
	188	/* Check the PTE flags */
	189	if (st->current_flags) {
	190	dump_addr(st, addr);
	191
	192	/* Dump all the flags */
	193	if (pg_level[st->level].flag)
	194	dump_flag_info(st, pg_level[st->level].flag,
	195	st->current_flags,
	196	pg_level[st->level].num);
	197
aae85e3c	198	seq_putc(st->seq, '\n');
8eb07b18 RG	199	}
	200
	201	/*
	202	* Address indicates we have passed the end of the
	203	* current section of virtual memory
	204	*/
	205	while (addr >= st->marker[1].start_address) {
	206	st->marker++;
	207	seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
	208	}
	209	st->start_address = addr;
aaa22952 OH	210	st->start_pa = pa;
aaa22952 OH	211	st->last_pa = pa;
8eb07b18 RG	212	st->current_flags = flag;
8eb07b18 RG	213	st->level = level;
aaa22952 OH	214	} else {
aaa22952 OH	215	st->last_pa = pa;
8eb07b18 RG	216	}
	217	}
	218
	219	static void walk_pte(struct pg_state st, pmd_t pmd, unsigned long start)
	220	{
	221	pte_t *pte = pte_offset_kernel(pmd, 0);
	222	unsigned long addr;
	223	unsigned int i;
	224
	225	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
	226	addr = start + i * PAGE_SIZE;
	227	note_page(st, addr, 4, pte_val(*pte));
	228
	229	}
	230	}
	231
	232	static void walk_pmd(struct pg_state st, pud_t pud, unsigned long start)
	233	{
	234	pmd_t *pmd = pmd_offset(pud, 0);
	235	unsigned long addr;
	236	unsigned int i;
	237
	238	for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
	239	addr = start + i * PMD_SIZE;
bfb9956a	240	if (!pmd_none(pmd) && !pmd_huge(pmd))
8eb07b18 RG	241	/* pmd exists */
	242	walk_pte(st, pmd, addr);
	243	else
	244	note_page(st, addr, 3, pmd_val(*pmd));
	245	}
	246	}
	247
	248	static void walk_pud(struct pg_state st, pgd_t pgd, unsigned long start)
	249	{
	250	pud_t *pud = pud_offset(pgd, 0);
	251	unsigned long addr;
	252	unsigned int i;
	253
	254	for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
	255	addr = start + i * PUD_SIZE;
bfb9956a	256	if (!pud_none(pud) && !pud_huge(pud))
8eb07b18 RG	257	/* pud exists */
	258	walk_pmd(st, pud, addr);
	259	else
	260	note_page(st, addr, 2, pud_val(*pud));
	261	}
	262	}
	263
	264	static void walk_pagetables(struct pg_state *st)
	265	{
	266	pgd_t *pgd = pgd_offset_k(0UL);
	267	unsigned int i;
	268	unsigned long addr;
	269
	270	/*
	271	* Traverse the linux pagetable structure and dump pages that are in
	272	* the hash pagetable.
	273	*/
	274	for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
	275	addr = KERN_VIRT_START + i * PGDIR_SIZE;
bfb9956a	276	if (!pgd_none(pgd) && !pgd_huge(pgd))
8eb07b18 RG	277	/* pgd exists */
	278	walk_pud(st, pgd, addr);
	279	else
	280	note_page(st, addr, 1, pgd_val(*pgd));
	281	}
	282	}
	283
	284	static void populate_markers(void)
	285	{
6c01bbd2 CL	286	int i = 0;
	287
	288	address_markers[i++].start_address = PAGE_OFFSET;
	289	address_markers[i++].start_address = VMALLOC_START;
	290	address_markers[i++].start_address = VMALLOC_END;
	291	#ifdef CONFIG_PPC64
	292	address_markers[i++].start_address = ISA_IO_BASE;
	293	address_markers[i++].start_address = ISA_IO_END;
	294	address_markers[i++].start_address = PHB_IO_BASE;
	295	address_markers[i++].start_address = PHB_IO_END;
	296	address_markers[i++].start_address = IOREMAP_BASE;
	297	address_markers[i++].start_address = IOREMAP_END;
4e003747	298	#ifdef CONFIG_PPC_BOOK3S_64
6c01bbd2	299	address_markers[i++].start_address = H_VMEMMAP_BASE;
8eb07b18	300	#else
6c01bbd2 CL	301	address_markers[i++].start_address = VMEMMAP_BASE;
	302	#endif
	303	#else /* !CONFIG_PPC64 */
	304	address_markers[i++].start_address = ioremap_bot;
	305	address_markers[i++].start_address = IOREMAP_TOP;
	306	#ifdef CONFIG_NOT_COHERENT_CACHE
	307	address_markers[i++].start_address = IOREMAP_TOP;
	308	address_markers[i++].start_address = IOREMAP_TOP +
	309	CONFIG_CONSISTENT_SIZE;
	310	#endif
	311	#ifdef CONFIG_HIGHMEM
	312	address_markers[i++].start_address = PKMAP_BASE;
	313	address_markers[i++].start_address = PKMAP_ADDR(LAST_PKMAP);
8eb07b18	314	#endif
6c01bbd2 CL	315	address_markers[i++].start_address = FIXADDR_START;
	316	address_markers[i++].start_address = FIXADDR_TOP;
	317	#endif /* CONFIG_PPC64 */
8eb07b18 RG	318	}
	319
	320	static int ptdump_show(struct seq_file m, void v)
	321	{
	322	struct pg_state st = {
	323	.seq = m,
	324	.start_address = KERN_VIRT_START,
	325	.marker = address_markers,
	326	};
	327	/* Traverse kernel page tables */
	328	walk_pagetables(&st);
	329	note_page(&st, 0, 0, 0);
	330	return 0;
	331	}
	332
	333
	334	static int ptdump_open(struct inode inode, struct file file)
	335	{
	336	return single_open(file, ptdump_show, NULL);
	337	}
	338
	339	static const struct file_operations ptdump_fops = {
	340	.open = ptdump_open,
	341	.read = seq_read,
	342	.llseek = seq_lseek,
	343	.release = single_release,
	344	};
	345
	346	static void build_pgtable_complete_mask(void)
	347	{
	348	unsigned int i, j;
	349
	350	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
	351	if (pg_level[i].flag)
	352	for (j = 0; j < pg_level[i].num; j++)
	353	pg_level[i].mask \|= pg_level[i].flag[j].mask;
	354	}
	355
	356	static int ptdump_init(void)
	357	{
	358	struct dentry *debugfs_file;
	359
	360	populate_markers();
	361	build_pgtable_complete_mask();
2505820f	362	debugfs_file = debugfs_create_file("kernel_page_tables", 0400, NULL,
8eb07b18 RG	363	NULL, &ptdump_fops);
	364	return debugfs_file ? 0 : -ENOMEM;
	365	}
	366	device_initcall(ptdump_init);