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e76e82d7 HC |
1 | #include <linux/seq_file.h> |
2 | #include <linux/debugfs.h> | |
3 | #include <linux/module.h> | |
4 | #include <linux/mm.h> | |
5 | #include <asm/sections.h> | |
6 | #include <asm/pgtable.h> | |
7 | ||
8 | static unsigned long max_addr; | |
9 | ||
10 | struct addr_marker { | |
11 | unsigned long start_address; | |
12 | const char *name; | |
13 | }; | |
14 | ||
15 | enum address_markers_idx { | |
16 | IDENTITY_NR = 0, | |
17 | KERNEL_START_NR, | |
18 | KERNEL_END_NR, | |
19 | VMEMMAP_NR, | |
20 | VMALLOC_NR, | |
21 | }; | |
22 | ||
23 | static struct addr_marker address_markers[] = { | |
24 | [IDENTITY_NR] = {0, "Identity Mapping"}, | |
25 | [KERNEL_START_NR] = {(unsigned long)&_stext, "Kernel Image Start"}, | |
26 | [KERNEL_END_NR] = {(unsigned long)&_end, "Kernel Image End"}, | |
27 | [VMEMMAP_NR] = {0, "vmemmap Area"}, | |
28 | [VMALLOC_NR] = {0, "vmalloc Area"}, | |
29 | { -1, NULL } | |
30 | }; | |
31 | ||
32 | struct pg_state { | |
33 | int level; | |
34 | unsigned int current_prot; | |
35 | unsigned long start_address; | |
36 | unsigned long current_address; | |
37 | const struct addr_marker *marker; | |
38 | }; | |
39 | ||
40 | static void print_prot(struct seq_file *m, unsigned int pr, int level) | |
41 | { | |
42 | static const char * const level_name[] = | |
43 | { "ASCE", "PGD", "PUD", "PMD", "PTE" }; | |
44 | ||
45 | seq_printf(m, "%s ", level_name[level]); | |
46 | if (pr & _PAGE_INVALID) | |
47 | seq_printf(m, "I\n"); | |
48 | else | |
49 | seq_printf(m, "%s\n", pr & _PAGE_RO ? "RO" : "RW"); | |
50 | } | |
51 | ||
52 | static void note_page(struct seq_file *m, struct pg_state *st, | |
53 | unsigned int new_prot, int level) | |
54 | { | |
55 | static const char units[] = "KMGTPE"; | |
56 | int width = sizeof(unsigned long) * 2; | |
57 | const char *unit = units; | |
58 | unsigned int prot, cur; | |
59 | unsigned long delta; | |
60 | ||
61 | /* | |
62 | * If we have a "break" in the series, we need to flush the state | |
63 | * that we have now. "break" is either changing perms, levels or | |
64 | * address space marker. | |
65 | */ | |
66 | prot = new_prot; | |
67 | cur = st->current_prot; | |
68 | ||
69 | if (!st->level) { | |
70 | /* First entry */ | |
71 | st->current_prot = new_prot; | |
72 | st->level = level; | |
73 | st->marker = address_markers; | |
74 | seq_printf(m, "---[ %s ]---\n", st->marker->name); | |
75 | } else if (prot != cur || level != st->level || | |
76 | st->current_address >= st->marker[1].start_address) { | |
77 | /* Print the actual finished series */ | |
78 | seq_printf(m, "0x%0*lx-0x%0*lx", | |
79 | width, st->start_address, | |
80 | width, st->current_address); | |
81 | delta = (st->current_address - st->start_address) >> 10; | |
82 | while (!(delta & 0x3ff) && unit[1]) { | |
83 | delta >>= 10; | |
84 | unit++; | |
85 | } | |
86 | seq_printf(m, "%9lu%c ", delta, *unit); | |
87 | print_prot(m, st->current_prot, st->level); | |
88 | if (st->current_address >= st->marker[1].start_address) { | |
89 | st->marker++; | |
90 | seq_printf(m, "---[ %s ]---\n", st->marker->name); | |
91 | } | |
92 | st->start_address = st->current_address; | |
93 | st->current_prot = new_prot; | |
94 | st->level = level; | |
95 | } | |
96 | } | |
97 | ||
98 | /* | |
99 | * The actual page table walker functions. In order to keep the implementation | |
100 | * of print_prot() short, we only check and pass _PAGE_INVALID and _PAGE_RO | |
101 | * flags to note_page() if a region, segment or page table entry is invalid or | |
102 | * read-only. | |
103 | * After all it's just a hint that the current level being walked contains an | |
104 | * invalid or read-only entry. | |
105 | */ | |
106 | static void walk_pte_level(struct seq_file *m, struct pg_state *st, | |
107 | pmd_t *pmd, unsigned long addr) | |
108 | { | |
109 | unsigned int prot; | |
110 | pte_t *pte; | |
111 | int i; | |
112 | ||
113 | for (i = 0; i < PTRS_PER_PTE && addr < max_addr; i++) { | |
114 | st->current_address = addr; | |
115 | pte = pte_offset_kernel(pmd, addr); | |
116 | prot = pte_val(*pte) & (_PAGE_RO | _PAGE_INVALID); | |
117 | note_page(m, st, prot, 4); | |
118 | addr += PAGE_SIZE; | |
119 | } | |
120 | } | |
121 | ||
122 | static void walk_pmd_level(struct seq_file *m, struct pg_state *st, | |
123 | pud_t *pud, unsigned long addr) | |
124 | { | |
125 | unsigned int prot; | |
126 | pmd_t *pmd; | |
127 | int i; | |
128 | ||
129 | for (i = 0; i < PTRS_PER_PMD && addr < max_addr; i++) { | |
130 | st->current_address = addr; | |
131 | pmd = pmd_offset(pud, addr); | |
132 | if (!pmd_none(*pmd)) { | |
133 | if (pmd_large(*pmd)) { | |
134 | prot = pmd_val(*pmd) & _SEGMENT_ENTRY_RO; | |
135 | note_page(m, st, prot, 3); | |
136 | } else | |
137 | walk_pte_level(m, st, pmd, addr); | |
138 | } else | |
139 | note_page(m, st, _PAGE_INVALID, 3); | |
140 | addr += PMD_SIZE; | |
141 | } | |
142 | } | |
143 | ||
144 | static void walk_pud_level(struct seq_file *m, struct pg_state *st, | |
145 | pgd_t *pgd, unsigned long addr) | |
146 | { | |
147 | pud_t *pud; | |
148 | int i; | |
149 | ||
150 | for (i = 0; i < PTRS_PER_PUD && addr < max_addr; i++) { | |
151 | st->current_address = addr; | |
152 | pud = pud_offset(pgd, addr); | |
153 | if (!pud_none(*pud)) | |
154 | walk_pmd_level(m, st, pud, addr); | |
155 | else | |
156 | note_page(m, st, _PAGE_INVALID, 2); | |
157 | addr += PUD_SIZE; | |
158 | } | |
159 | } | |
160 | ||
161 | static void walk_pgd_level(struct seq_file *m) | |
162 | { | |
163 | unsigned long addr = 0; | |
164 | struct pg_state st; | |
165 | pgd_t *pgd; | |
166 | int i; | |
167 | ||
168 | memset(&st, 0, sizeof(st)); | |
169 | for (i = 0; i < PTRS_PER_PGD && addr < max_addr; i++) { | |
170 | st.current_address = addr; | |
171 | pgd = pgd_offset_k(addr); | |
172 | if (!pgd_none(*pgd)) | |
173 | walk_pud_level(m, &st, pgd, addr); | |
174 | else | |
175 | note_page(m, &st, _PAGE_INVALID, 1); | |
176 | addr += PGDIR_SIZE; | |
177 | } | |
178 | /* Flush out the last page */ | |
179 | st.current_address = max_addr; | |
180 | note_page(m, &st, 0, 0); | |
181 | } | |
182 | ||
183 | static int ptdump_show(struct seq_file *m, void *v) | |
184 | { | |
185 | walk_pgd_level(m); | |
186 | return 0; | |
187 | } | |
188 | ||
189 | static int ptdump_open(struct inode *inode, struct file *filp) | |
190 | { | |
191 | return single_open(filp, ptdump_show, NULL); | |
192 | } | |
193 | ||
194 | static const struct file_operations ptdump_fops = { | |
195 | .open = ptdump_open, | |
196 | .read = seq_read, | |
197 | .llseek = seq_lseek, | |
198 | .release = single_release, | |
199 | }; | |
200 | ||
201 | static int pt_dump_init(void) | |
202 | { | |
203 | /* | |
204 | * Figure out the maximum virtual address being accessible with the | |
205 | * kernel ASCE. We need this to keep the page table walker functions | |
206 | * from accessing non-existent entries. | |
207 | */ | |
208 | #ifdef CONFIG_64BIT | |
209 | max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2; | |
210 | max_addr = 1UL << (max_addr * 11 + 31); | |
211 | #else | |
212 | max_addr = 1UL << 31; | |
213 | #endif | |
214 | address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap; | |
215 | address_markers[VMALLOC_NR].start_address = VMALLOC_START; | |
216 | debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops); | |
217 | return 0; | |
218 | } | |
219 | device_initcall(pt_dump_init); |