[mirror_ubuntu-hirsute-kernel.git] / arch / riscv / mm / ptdump.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2019 SiFive
 */

#include <linux/efi.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/ptdump.h>

#include <asm/ptdump.h>
#include <linux/pgtable.h>
#include <asm/kasan.h>

#define pt_dump_seq_printf(m, fmt, args...)	\
({						\
	if (m)					\
		seq_printf(m, fmt, ##args);	\
})

#define pt_dump_seq_puts(m, fmt)	\
({					\
	if (m)				\
		seq_printf(m, fmt);	\
})

/*
 * 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.
 */
struct pg_state {
	struct ptdump_state ptdump;
	struct seq_file *seq;
	const struct addr_marker *marker;
	unsigned long start_address;
	unsigned long start_pa;
	unsigned long last_pa;
	int level;
	u64 current_prot;
	bool check_wx;
	unsigned long wx_pages;
};

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

/* Private information for debugfs */
struct ptd_mm_info {
	struct mm_struct		*mm;
	const struct addr_marker	*markers;
	unsigned long base_addr;
	unsigned long end;
};

static struct addr_marker address_markers[] = {
#ifdef CONFIG_KASAN
	{KASAN_SHADOW_START,	"Kasan shadow start"},
	{KASAN_SHADOW_END,	"Kasan shadow end"},
#endif
	{FIXADDR_START,		"Fixmap start"},
	{FIXADDR_TOP,		"Fixmap end"},
	{PCI_IO_START,		"PCI I/O start"},
	{PCI_IO_END,		"PCI I/O end"},
#ifdef CONFIG_SPARSEMEM_VMEMMAP
	{VMEMMAP_START,		"vmemmap start"},
	{VMEMMAP_END,		"vmemmap end"},
#endif
	{VMALLOC_START,		"vmalloc() area"},
	{VMALLOC_END,		"vmalloc() end"},
	{PAGE_OFFSET,		"Linear mapping"},
	{-1, NULL},
};

static struct ptd_mm_info kernel_ptd_info = {
	.mm		= &init_mm,
	.markers	= address_markers,
	.base_addr	= KERN_VIRT_START,
	.end		= ULONG_MAX,
};

#ifdef CONFIG_EFI
static struct addr_marker efi_addr_markers[] = {
		{ 0,		"UEFI runtime start" },
		{ SZ_1G,	"UEFI runtime end" },
		{ -1,		NULL }
};

static struct ptd_mm_info efi_ptd_info = {
	.mm		= &efi_mm,
	.markers	= efi_addr_markers,
	.base_addr	= 0,
	.end		= SZ_2G,
};
#endif

/* Page Table Entry */
struct prot_bits {
	u64 mask;
	u64 val;
	const char *set;
	const char *clear;
};

static const struct prot_bits pte_bits[] = {
	{
		.mask = _PAGE_SOFT,
		.val = _PAGE_SOFT,
		.set = "RSW",
		.clear = "   ",
	}, {
		.mask = _PAGE_DIRTY,
		.val = _PAGE_DIRTY,
		.set = "D",
		.clear = ".",
	}, {
		.mask = _PAGE_ACCESSED,
		.val = _PAGE_ACCESSED,
		.set = "A",
		.clear = ".",
	}, {
		.mask = _PAGE_GLOBAL,
		.val = _PAGE_GLOBAL,
		.set = "G",
		.clear = ".",
	}, {
		.mask = _PAGE_USER,
		.val = _PAGE_USER,
		.set = "U",
		.clear = ".",
	}, {
		.mask = _PAGE_EXEC,
		.val = _PAGE_EXEC,
		.set = "X",
		.clear = ".",
	}, {
		.mask = _PAGE_WRITE,
		.val = _PAGE_WRITE,
		.set = "W",
		.clear = ".",
	}, {
		.mask = _PAGE_READ,
		.val = _PAGE_READ,
		.set = "R",
		.clear = ".",
	}, {
		.mask = _PAGE_PRESENT,
		.val = _PAGE_PRESENT,
		.set = "V",
		.clear = ".",
	}
};

/* Page Level */
struct pg_level {
	const char *name;
	u64 mask;
};

static struct pg_level pg_level[] = {
	{ /* pgd */
		.name = "PGD",
	}, { /* p4d */
		.name = (CONFIG_PGTABLE_LEVELS > 4) ? "P4D" : "PGD",
	}, { /* pud */
		.name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
	}, { /* pmd */
		.name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD",
	}, { /* pte */
		.name = "PTE",
	},
};

static void dump_prot(struct pg_state *st)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(pte_bits); i++) {
		const char *s;

		if ((st->current_prot & pte_bits[i].mask) == pte_bits[i].val)
			s = pte_bits[i].set;
		else
			s = pte_bits[i].clear;

		if (s)
			pt_dump_seq_printf(st->seq, " %s", s);
	}
}

#ifdef CONFIG_64BIT
#define ADDR_FORMAT	"0x%016lx"
#else
#define ADDR_FORMAT	"0x%08lx"
#endif
static void dump_addr(struct pg_state *st, unsigned long addr)
{
	static const char units[] = "KMGTPE";
	const char *unit = units;
	unsigned long delta;

	pt_dump_seq_printf(st->seq, ADDR_FORMAT "-" ADDR_FORMAT "   ",
			   st->start_address, addr);

	pt_dump_seq_printf(st->seq, " " ADDR_FORMAT " ", st->start_pa);
	delta = (addr - st->start_address) >> 10;

	while (!(delta & 1023) && unit[1]) {
		delta >>= 10;
		unit++;
	}

	pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit,
			   pg_level[st->level].name);
}

static void note_prot_wx(struct pg_state *st, unsigned long addr)
{
	if (!st->check_wx)
		return;

	if ((st->current_prot & (_PAGE_WRITE | _PAGE_EXEC)) !=
	    (_PAGE_WRITE | _PAGE_EXEC))
		return;

	WARN_ONCE(1, "riscv/mm: Found insecure W+X mapping at address %p/%pS\n",
		  (void *)st->start_address, (void *)st->start_address);

	st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
}

static void note_page(struct ptdump_state *pt_st, unsigned long addr,
		      int level, u64 val)
{
	struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
	u64 pa = PFN_PHYS(pte_pfn(__pte(val)));
	u64 prot = 0;

	if (level >= 0)
		prot = val & pg_level[level].mask;

	if (st->level == -1) {
		st->level = level;
		st->current_prot = prot;
		st->start_address = addr;
		st->start_pa = pa;
		st->last_pa = pa;
		pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
	} else if (prot != st->current_prot ||
		   level != st->level || addr >= st->marker[1].start_address) {
		if (st->current_prot) {
			note_prot_wx(st, addr);
			dump_addr(st, addr);
			dump_prot(st);
			pt_dump_seq_puts(st->seq, "\n");
		}

		while (addr >= st->marker[1].start_address) {
			st->marker++;
			pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
					   st->marker->name);
		}

		st->start_address = addr;
		st->start_pa = pa;
		st->last_pa = pa;
		st->current_prot = prot;
		st->level = level;
	} else {
		st->last_pa = pa;
	}
}

static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo)
{
	struct pg_state st = {
		.seq = s,
		.marker = pinfo->markers,
		.level = -1,
		.ptdump = {
			.note_page = note_page,
			.range = (struct ptdump_range[]) {
				{pinfo->base_addr, pinfo->end},
				{0, 0}
			}
		}
	};

	ptdump_walk_pgd(&st.ptdump, pinfo->mm, NULL);
}

void ptdump_check_wx(void)
{
	struct pg_state st = {
		.seq = NULL,
		.marker = (struct addr_marker[]) {
			{0, NULL},
			{-1, NULL},
		},
		.level = -1,
		.check_wx = true,
		.ptdump = {
			.note_page = note_page,
			.range = (struct ptdump_range[]) {
				{KERN_VIRT_START, ULONG_MAX},
				{0, 0}
			}
		}
	};

	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);

	if (st.wx_pages)
		pr_warn("Checked W+X mappings: failed, %lu W+X pages found\n",
			st.wx_pages);
	else
		pr_info("Checked W+X mappings: passed, no W+X pages found\n");
}

static int ptdump_show(struct seq_file *m, void *v)
{
	ptdump_walk(m, m->private);

	return 0;
}

DEFINE_SHOW_ATTRIBUTE(ptdump);

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

	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
		for (j = 0; j < ARRAY_SIZE(pte_bits); j++)
			pg_level[i].mask |= pte_bits[j].mask;

	debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info,
			    &ptdump_fops);
#ifdef CONFIG_EFI
	if (efi_enabled(EFI_RUNTIME_SERVICES))
		debugfs_create_file("efi_page_tables", 0400, NULL, &efi_ptd_info,
				    &ptdump_fops);
#endif

	return 0;
}

device_initcall(ptdump_init);
Commit	Line	Data
59c4da86 ZL	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* Copyright (C) 2019 SiFive
	4	*/
	5
de22d210	6	#include <linux/efi.h>
59c4da86 ZL	7	#include <linux/init.h>
	8	#include <linux/debugfs.h>
	9	#include <linux/seq_file.h>
	10	#include <linux/ptdump.h>
	11
	12	#include <asm/ptdump.h>
ca5999fd	13	#include <linux/pgtable.h>
59c4da86 ZL	14	#include <asm/kasan.h>
	15
	16	#define pt_dump_seq_printf(m, fmt, args...) \
	17	({ \
	18	if (m) \
	19	seq_printf(m, fmt, ##args); \
	20	})
	21
	22	#define pt_dump_seq_puts(m, fmt) \
	23	({ \
	24	if (m) \
	25	seq_printf(m, fmt); \
	26	})
	27
	28	/*
	29	* The page dumper groups page table entries of the same type into a single
	30	* description. It uses pg_state to track the range information while
	31	* iterating over the pte entries. When the continuity is broken it then
	32	* dumps out a description of the range.
	33	*/
	34	struct pg_state {
	35	struct ptdump_state ptdump;
	36	struct seq_file *seq;
	37	const struct addr_marker *marker;
	38	unsigned long start_address;
	39	unsigned long start_pa;
	40	unsigned long last_pa;
	41	int level;
	42	u64 current_prot;
	43	bool check_wx;
	44	unsigned long wx_pages;
	45	};
	46
	47	/* Address marker */
	48	struct addr_marker {
	49	unsigned long start_address;
	50	const char *name;
	51	};
	52
de22d210 AP	53	/* Private information for debugfs */
	54	struct ptd_mm_info {
	55	struct mm_struct *mm;
	56	const struct addr_marker *markers;
	57	unsigned long base_addr;
	58	unsigned long end;
	59	};
	60
59c4da86 ZL	61	static struct addr_marker address_markers[] = {
	62	#ifdef CONFIG_KASAN
	63	{KASAN_SHADOW_START, "Kasan shadow start"},
	64	{KASAN_SHADOW_END, "Kasan shadow end"},
	65	#endif
	66	{FIXADDR_START, "Fixmap start"},
	67	{FIXADDR_TOP, "Fixmap end"},
	68	{PCI_IO_START, "PCI I/O start"},
	69	{PCI_IO_END, "PCI I/O end"},
	70	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	71	{VMEMMAP_START, "vmemmap start"},
	72	{VMEMMAP_END, "vmemmap end"},
	73	#endif
	74	{VMALLOC_START, "vmalloc() area"},
	75	{VMALLOC_END, "vmalloc() end"},
	76	{PAGE_OFFSET, "Linear mapping"},
	77	{-1, NULL},
	78	};
	79
de22d210 AP	80	static struct ptd_mm_info kernel_ptd_info = {
	81	.mm = &init_mm,
	82	.markers = address_markers,
	83	.base_addr = KERN_VIRT_START,
	84	.end = ULONG_MAX,
	85	};
	86
	87	#ifdef CONFIG_EFI
	88	static struct addr_marker efi_addr_markers[] = {
	89	{ 0, "UEFI runtime start" },
	90	{ SZ_1G, "UEFI runtime end" },
	91	{ -1, NULL }
	92	};
	93
	94	static struct ptd_mm_info efi_ptd_info = {
	95	.mm = &efi_mm,
	96	.markers = efi_addr_markers,
	97	.base_addr = 0,
	98	.end = SZ_2G,
	99	};
	100	#endif
	101
59c4da86 ZL	102	/* Page Table Entry */
	103	struct prot_bits {
	104	u64 mask;
	105	u64 val;
	106	const char *set;
	107	const char *clear;
	108	};
	109
	110	static const struct prot_bits pte_bits[] = {
	111	{
	112	.mask = _PAGE_SOFT,
	113	.val = _PAGE_SOFT,
	114	.set = "RSW",
	115	.clear = " ",
	116	}, {
	117	.mask = _PAGE_DIRTY,
	118	.val = _PAGE_DIRTY,
	119	.set = "D",
	120	.clear = ".",
	121	}, {
	122	.mask = _PAGE_ACCESSED,
	123	.val = _PAGE_ACCESSED,
	124	.set = "A",
	125	.clear = ".",
	126	}, {
	127	.mask = _PAGE_GLOBAL,
	128	.val = _PAGE_GLOBAL,
	129	.set = "G",
	130	.clear = ".",
	131	}, {
	132	.mask = _PAGE_USER,
	133	.val = _PAGE_USER,
	134	.set = "U",
	135	.clear = ".",
	136	}, {
	137	.mask = _PAGE_EXEC,
	138	.val = _PAGE_EXEC,
	139	.set = "X",
	140	.clear = ".",
	141	}, {
	142	.mask = _PAGE_WRITE,
	143	.val = _PAGE_WRITE,
	144	.set = "W",
	145	.clear = ".",
	146	}, {
	147	.mask = _PAGE_READ,
	148	.val = _PAGE_READ,
	149	.set = "R",
	150	.clear = ".",
	151	}, {
	152	.mask = _PAGE_PRESENT,
	153	.val = _PAGE_PRESENT,
	154	.set = "V",
	155	.clear = ".",
	156	}
	157	};
	158
	159	/* Page Level */
	160	struct pg_level {
	161	const char *name;
	162	u64 mask;
	163	};
	164
	165	static struct pg_level pg_level[] = {
166	{ /* pgd */
167	.name = "PGD",
168	}, { /* p4d */
169	.name = (CONFIG_PGTABLE_LEVELS > 4) ? "P4D" : "PGD",
170	}, { /* pud */
171	.name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
172	}, { /* pmd */
173	.name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD",
174	}, { /* pte */
175	.name = "PTE",
176	},
177	};
178
179	static void dump_prot(struct pg_state *st)
180	{
181	unsigned int i;
182
183	for (i = 0; i < ARRAY_SIZE(pte_bits); i++) {
184	const char *s;
185
186	if ((st->current_prot & pte_bits[i].mask) == pte_bits[i].val)
187	s = pte_bits[i].set;
188	else
189	s = pte_bits[i].clear;
190
191	if (s)
192	pt_dump_seq_printf(st->seq, " %s", s);
193	}
194	}
195
196	#ifdef CONFIG_64BIT
197	#define ADDR_FORMAT "0x%016lx"
198	#else
199	#define ADDR_FORMAT "0x%08lx"
200	#endif
201	static void dump_addr(struct pg_state *st, unsigned long addr)
202	{
203	static const char units[] = "KMGTPE";
204	const char *unit = units;
205	unsigned long delta;
206
207	pt_dump_seq_printf(st->seq, ADDR_FORMAT "-" ADDR_FORMAT " ",
208	st->start_address, addr);
209
210	pt_dump_seq_printf(st->seq, " " ADDR_FORMAT " ", st->start_pa);
211	delta = (addr - st->start_address) >> 10;
212
213	while (!(delta & 1023) && unit[1]) {
214	delta >>= 10;
215	unit++;
216	}
217
218	pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit,
219	pg_level[st->level].name);
220	}
221
222	static void note_prot_wx(struct pg_state *st, unsigned long addr)
223	{
224	if (!st->check_wx)
225	return;
226
227	if ((st->current_prot & (_PAGE_WRITE \| _PAGE_EXEC)) !=
228	(_PAGE_WRITE \| _PAGE_EXEC))
229	return;
230
231	WARN_ONCE(1, "riscv/mm: Found insecure W+X mapping at address %p/%pS\n",
232	(void )st->start_address, (void )st->start_address);
233
234	st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
235	}
236
237	static void note_page(struct ptdump_state *pt_st, unsigned long addr,
99395ee3	238	int level, u64 val)
59c4da86 ZL	239	{
	240	struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
	241	u64 pa = PFN_PHYS(pte_pfn(__pte(val)));
	242	u64 prot = 0;
	243
	244	if (level >= 0)
	245	prot = val & pg_level[level].mask;
	246
	247	if (st->level == -1) {
	248	st->level = level;
	249	st->current_prot = prot;
	250	st->start_address = addr;
	251	st->start_pa = pa;
	252	st->last_pa = pa;
	253	pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
	254	} else if (prot != st->current_prot \|\|
	255	level != st->level \|\| addr >= st->marker[1].start_address) {
	256	if (st->current_prot) {
	257	note_prot_wx(st, addr);
	258	dump_addr(st, addr);
	259	dump_prot(st);
	260	pt_dump_seq_puts(st->seq, "\n");
	261	}
	262
	263	while (addr >= st->marker[1].start_address) {
	264	st->marker++;
	265	pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
	266	st->marker->name);
	267	}
	268
	269	st->start_address = addr;
	270	st->start_pa = pa;
	271	st->last_pa = pa;
	272	st->current_prot = prot;
	273	st->level = level;
	274	} else {
	275	st->last_pa = pa;
	276	}
	277	}
	278
de22d210	279	static void ptdump_walk(struct seq_file s, struct ptd_mm_info pinfo)
59c4da86 ZL	280	{
	281	struct pg_state st = {
	282	.seq = s,
de22d210	283	.marker = pinfo->markers,
59c4da86 ZL	284	.level = -1,
	285	.ptdump = {
	286	.note_page = note_page,
	287	.range = (struct ptdump_range[]) {
de22d210	288	{pinfo->base_addr, pinfo->end},
59c4da86 ZL	289	{0, 0}
	290	}
	291	}
	292	};
	293
de22d210	294	ptdump_walk_pgd(&st.ptdump, pinfo->mm, NULL);
59c4da86 ZL	295	}
	296
	297	void ptdump_check_wx(void)
	298	{
	299	struct pg_state st = {
	300	.seq = NULL,
	301	.marker = (struct addr_marker[]) {
	302	{0, NULL},
	303	{-1, NULL},
	304	},
	305	.level = -1,
	306	.check_wx = true,
	307	.ptdump = {
	308	.note_page = note_page,
	309	.range = (struct ptdump_range[]) {
	310	{KERN_VIRT_START, ULONG_MAX},
	311	{0, 0}
	312	}
	313	}
	314	};
	315
	316	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
	317
	318	if (st.wx_pages)
	319	pr_warn("Checked W+X mappings: failed, %lu W+X pages found\n",
	320	st.wx_pages);
	321	else
	322	pr_info("Checked W+X mappings: passed, no W+X pages found\n");
	323	}
	324
	325	static int ptdump_show(struct seq_file m, void v)
	326	{
de22d210	327	ptdump_walk(m, m->private);
59c4da86 ZL	328
	329	return 0;
	330	}
	331
	332	DEFINE_SHOW_ATTRIBUTE(ptdump);
	333
	334	static int ptdump_init(void)
	335	{
	336	unsigned int i, j;
	337
	338	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
	339	for (j = 0; j < ARRAY_SIZE(pte_bits); j++)
	340	pg_level[i].mask \|= pte_bits[j].mask;
	341
de22d210	342	debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info,
59c4da86	343	&ptdump_fops);
de22d210 AP	344	#ifdef CONFIG_EFI
	345	if (efi_enabled(EFI_RUNTIME_SERVICES))
	346	debugfs_create_file("efi_page_tables", 0400, NULL, &efi_ptd_info,
	347	&ptdump_fops);
	348	#endif
59c4da86 ZL	349
	350	return 0;
	351	}
	352
	353	device_initcall(ptdump_init);