arch/s390/mm/dump_pagetables.c

   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 #ifdef CONFIG_64BIT
  22         MODULES_NR,
  23 #endif
  24 };
  25
  26 static struct addr_marker address_markers[] = {
  27         [IDENTITY_NR]     = {0, "Identity Mapping"},
  28         [KERNEL_START_NR] = {(unsigned long)&_stext, "Kernel Image Start"},
  29         [KERNEL_END_NR]   = {(unsigned long)&_end, "Kernel Image End"},
  30         [VMEMMAP_NR]      = {0, "vmemmap Area"},
  31         [VMALLOC_NR]      = {0, "vmalloc Area"},
  32 #ifdef CONFIG_64BIT
  33         [MODULES_NR]      = {0, "Modules Area"},
  34 #endif
  35         { -1, NULL }
  36 };
  37
  38 struct pg_state {
  39         int level;
  40         unsigned int current_prot;
  41         unsigned long start_address;
  42         unsigned long current_address;
  43         const struct addr_marker *marker;
  44 };
  45
  46 static void print_prot(struct seq_file *m, unsigned int pr, int level)
  47 {
  48         static const char * const level_name[] =
  49                 { "ASCE", "PGD", "PUD", "PMD", "PTE" };
  50
  51         seq_printf(m, "%s ", level_name[level]);
  52         if (pr & _PAGE_INVALID) {
  53                 seq_printf(m, "I\n");
  54                 return;
  55         }
  56         seq_printf(m, "%s", pr & _PAGE_PROTECT ? "RO " : "RW ");
  57         seq_putc(m, '\n');
  58 }
  59
  60 static void note_page(struct seq_file *m, struct pg_state *st,
  61                      unsigned int new_prot, int level)
  62 {
  63         static const char units[] = "KMGTPE";
  64         int width = sizeof(unsigned long) * 2;
  65         const char *unit = units;
  66         unsigned int prot, cur;
  67         unsigned long delta;
  68
  69         /*
  70          * If we have a "break" in the series, we need to flush the state
  71          * that we have now. "break" is either changing perms, levels or
  72          * address space marker.
  73          */
  74         prot = new_prot;
  75         cur = st->current_prot;
  76
  77         if (!st->level) {
  78                 /* First entry */
  79                 st->current_prot = new_prot;
  80                 st->level = level;
  81                 st->marker = address_markers;
  82                 seq_printf(m, "---[ %s ]---\n", st->marker->name);
  83         } else if (prot != cur || level != st->level ||
  84                    st->current_address >= st->marker[1].start_address) {
  85                 /* Print the actual finished series */
  86                 seq_printf(m, "0x%0*lx-0x%0*lx",
  87                            width, st->start_address,
  88                            width, st->current_address);
  89                 delta = (st->current_address - st->start_address) >> 10;
  90                 while (!(delta & 0x3ff) && unit[1]) {
  91                         delta >>= 10;
  92                         unit++;
  93                 }
  94                 seq_printf(m, "%9lu%c ", delta, *unit);
  95                 print_prot(m, st->current_prot, st->level);
  96                 if (st->current_address >= st->marker[1].start_address) {
  97                         st->marker++;
  98                         seq_printf(m, "---[ %s ]---\n", st->marker->name);
  99                 }
 100                 st->start_address = st->current_address;
 101                 st->current_prot = new_prot;
 102                 st->level = level;
 103         }
 104 }
 105
 106 /*
 107  * The actual page table walker functions. In order to keep the
 108  * implementation of print_prot() short, we only check and pass
 109  * _PAGE_INVALID and _PAGE_PROTECT flags to note_page() if a region,
 110  * segment or page table entry is invalid or read-only.
 111  * After all it's just a hint that the current level being walked
 112  * contains an invalid or read-only entry.
 113  */
 114 static void walk_pte_level(struct seq_file *m, struct pg_state *st,
 115                            pmd_t *pmd, unsigned long addr)
 116 {
 117         unsigned int prot;
 118         pte_t *pte;
 119         int i;
 120
 121         for (i = 0; i < PTRS_PER_PTE && addr < max_addr; i++) {
 122                 st->current_address = addr;
 123                 pte = pte_offset_kernel(pmd, addr);
 124                 prot = pte_val(*pte) & (_PAGE_PROTECT | _PAGE_INVALID);
 125                 note_page(m, st, prot, 4);
 126                 addr += PAGE_SIZE;
 127         }
 128 }
 129
 130 #ifdef CONFIG_64BIT
 131 #define _PMD_PROT_MASK _SEGMENT_ENTRY_PROTECT
 132 #else
 133 #define _PMD_PROT_MASK 0
 134 #endif
 135
 136 static void walk_pmd_level(struct seq_file *m, struct pg_state *st,
 137                            pud_t *pud, unsigned long addr)
 138 {
 139         unsigned int prot;
 140         pmd_t *pmd;
 141         int i;
 142
 143         for (i = 0; i < PTRS_PER_PMD && addr < max_addr; i++) {
 144                 st->current_address = addr;
 145                 pmd = pmd_offset(pud, addr);
 146                 if (!pmd_none(*pmd)) {
 147                         if (pmd_large(*pmd)) {
 148                                 prot = pmd_val(*pmd) & _PMD_PROT_MASK;
 149                                 note_page(m, st, prot, 3);
 150                         } else
 151                                 walk_pte_level(m, st, pmd, addr);
 152                 } else
 153                         note_page(m, st, _PAGE_INVALID, 3);
 154                 addr += PMD_SIZE;
 155         }
 156 }
 157
 158 #ifdef CONFIG_64BIT
 159 #define _PUD_PROT_MASK _REGION3_ENTRY_RO
 160 #else
 161 #define _PUD_PROT_MASK 0
 162 #endif
 163
 164 static void walk_pud_level(struct seq_file *m, struct pg_state *st,
 165                            pgd_t *pgd, unsigned long addr)
 166 {
 167         unsigned int prot;
 168         pud_t *pud;
 169         int i;
 170
 171         for (i = 0; i < PTRS_PER_PUD && addr < max_addr; i++) {
 172                 st->current_address = addr;
 173                 pud = pud_offset(pgd, addr);
 174                 if (!pud_none(*pud))
 175                         if (pud_large(*pud)) {
 176                                 prot = pud_val(*pud) & _PUD_PROT_MASK;
 177                                 note_page(m, st, prot, 2);
 178                         } else
 179                                 walk_pmd_level(m, st, pud, addr);
 180                 else
 181                         note_page(m, st, _PAGE_INVALID, 2);
 182                 addr += PUD_SIZE;
 183         }
 184 }
 185
 186 static void walk_pgd_level(struct seq_file *m)
 187 {
 188         unsigned long addr = 0;
 189         struct pg_state st;
 190         pgd_t *pgd;
 191         int i;
 192
 193         memset(&st, 0, sizeof(st));
 194         for (i = 0; i < PTRS_PER_PGD && addr < max_addr; i++) {
 195                 st.current_address = addr;
 196                 pgd = pgd_offset_k(addr);
 197                 if (!pgd_none(*pgd))
 198                         walk_pud_level(m, &st, pgd, addr);
 199                 else
 200                         note_page(m, &st, _PAGE_INVALID, 1);
 201                 addr += PGDIR_SIZE;
 202         }
 203         /* Flush out the last page */
 204         st.current_address = max_addr;
 205         note_page(m, &st, 0, 0);
 206 }
 207
 208 static int ptdump_show(struct seq_file *m, void *v)
 209 {
 210         walk_pgd_level(m);
 211         return 0;
 212 }
 213
 214 static int ptdump_open(struct inode *inode, struct file *filp)
 215 {
 216         return single_open(filp, ptdump_show, NULL);
 217 }
 218
 219 static const struct file_operations ptdump_fops = {
 220         .open           = ptdump_open,
 221         .read           = seq_read,
 222         .llseek         = seq_lseek,
 223         .release        = single_release,
 224 };
 225
 226 static int pt_dump_init(void)
 227 {
 228         /*
 229          * Figure out the maximum virtual address being accessible with the
 230          * kernel ASCE. We need this to keep the page table walker functions
 231          * from accessing non-existent entries.
 232          */
 233 #ifdef CONFIG_32BIT
 234         max_addr = 1UL << 31;
 235 #else
 236         max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2;
 237         max_addr = 1UL << (max_addr * 11 + 31);
 238         address_markers[MODULES_NR].start_address = MODULES_VADDR;
 239 #endif
 240         address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap;
 241         address_markers[VMALLOC_NR].start_address = VMALLOC_START;
 242         debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops);
 243         return 0;
 244 }
 245 device_initcall(pt_dump_init);