arch/riscv/mm/ptdump.c - linux - Git at Google

 // 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;
 };

 enum address_markers_idx {
 	FIXMAP_START_NR,
 	FIXMAP_END_NR,
 	PCI_IO_START_NR,
 	PCI_IO_END_NR,
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 	VMEMMAP_START_NR,
 	VMEMMAP_END_NR,
 #endif
 	VMALLOC_START_NR,
 	VMALLOC_END_NR,
 	PAGE_OFFSET_NR,
 #ifdef CONFIG_KASAN
 	KASAN_SHADOW_START_NR,
 	KASAN_SHADOW_END_NR,
 #endif
 #ifdef CONFIG_64BIT
 	MODULES_MAPPING_NR,
 	KERNEL_MAPPING_NR,
 #endif
 	END_OF_SPACE_NR
 };

 static struct addr_marker address_markers[] = {
 	{0, "Fixmap start"},
 	{0, "Fixmap end"},
 	{0, "PCI I/O start"},
 	{0, "PCI I/O end"},
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 	{0, "vmemmap start"},
 	{0, "vmemmap end"},
 #endif
 	{0, "vmalloc() area"},
 	{0, "vmalloc() end"},
 	{0, "Linear mapping"},
 #ifdef CONFIG_KASAN
 	{0, "Kasan shadow start"},
 	{0, "Kasan shadow end"},
 #endif
 #ifdef CONFIG_64BIT
 	{0, "Modules/BPF mapping"},
 	{0, "Kernel mapping"},
 #endif
 	{-1, NULL},
 };

 static struct ptd_mm_info kernel_ptd_info = {
 	.mm		= &init_mm,
 	.markers	= address_markers,
 	.base_addr	= 0,
 	.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 __init ptdump_init(void)
 {
 	unsigned int i, j;

 	address_markers[FIXMAP_START_NR].start_address = FIXADDR_START;
 	address_markers[FIXMAP_END_NR].start_address = FIXADDR_TOP;
 	address_markers[PCI_IO_START_NR].start_address = PCI_IO_START;
 	address_markers[PCI_IO_END_NR].start_address = PCI_IO_END;
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 	address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
 	address_markers[VMEMMAP_END_NR].start_address = VMEMMAP_END;
 #endif
 	address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
 	address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
 	address_markers[PAGE_OFFSET_NR].start_address = PAGE_OFFSET;
 #ifdef CONFIG_KASAN
 	address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
 	address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
 #endif
 #ifdef CONFIG_64BIT
 	address_markers[MODULES_MAPPING_NR].start_address = MODULES_VADDR;
 	address_markers[KERNEL_MAPPING_NR].start_address = kernel_map.virt_addr;
 #endif

 	kernel_ptd_info.base_addr = KERN_VIRT_START;

 	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);
	// 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;
	};

	enum address_markers_idx {
	FIXMAP_START_NR,
	FIXMAP_END_NR,
	PCI_IO_START_NR,
	PCI_IO_END_NR,
	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	VMEMMAP_START_NR,
	VMEMMAP_END_NR,
	#endif
	VMALLOC_START_NR,
	VMALLOC_END_NR,
	PAGE_OFFSET_NR,
	#ifdef CONFIG_KASAN
	KASAN_SHADOW_START_NR,
	KASAN_SHADOW_END_NR,
	#endif
	#ifdef CONFIG_64BIT
	MODULES_MAPPING_NR,
	KERNEL_MAPPING_NR,
	#endif
	END_OF_SPACE_NR
	};

	static struct addr_marker address_markers[] = {
	{0, "Fixmap start"},
	{0, "Fixmap end"},
	{0, "PCI I/O start"},
	{0, "PCI I/O end"},
	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	{0, "vmemmap start"},
	{0, "vmemmap end"},
	#endif
	{0, "vmalloc() area"},
	{0, "vmalloc() end"},
	{0, "Linear mapping"},
	#ifdef CONFIG_KASAN
	{0, "Kasan shadow start"},
	{0, "Kasan shadow end"},
	#endif
	#ifdef CONFIG_64BIT
	{0, "Modules/BPF mapping"},
	{0, "Kernel mapping"},
	#endif
	{-1, NULL},
	};

	static struct ptd_mm_info kernel_ptd_info = {
	.mm = &init_mm,
	.markers = address_markers,
	.base_addr = 0,
	.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 __init ptdump_init(void)
	{
	unsigned int i, j;

	address_markers[FIXMAP_START_NR].start_address = FIXADDR_START;
	address_markers[FIXMAP_END_NR].start_address = FIXADDR_TOP;
	address_markers[PCI_IO_START_NR].start_address = PCI_IO_START;
	address_markers[PCI_IO_END_NR].start_address = PCI_IO_END;
	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
	address_markers[VMEMMAP_END_NR].start_address = VMEMMAP_END;
	#endif
	address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
	address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
	address_markers[PAGE_OFFSET_NR].start_address = PAGE_OFFSET;
	#ifdef CONFIG_KASAN
	address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
	address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
	#endif
	#ifdef CONFIG_64BIT
	address_markers[MODULES_MAPPING_NR].start_address = MODULES_VADDR;
	address_markers[KERNEL_MAPPING_NR].start_address = kernel_map.virt_addr;
	#endif

	kernel_ptd_info.base_addr = KERN_VIRT_START;

	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);