247 lines
6.1 KiB
C
247 lines
6.1 KiB
C
#include <linux/seq_file.h>
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#include <linux/debugfs.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <asm/sections.h>
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#include <asm/pgtable.h>
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static unsigned long max_addr;
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struct addr_marker {
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unsigned long start_address;
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const char *name;
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};
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enum address_markers_idx {
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IDENTITY_NR = 0,
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KERNEL_START_NR,
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KERNEL_END_NR,
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VMEMMAP_NR,
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VMALLOC_NR,
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#ifdef CONFIG_64BIT
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MODULES_NR,
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#endif
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};
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static struct addr_marker address_markers[] = {
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[IDENTITY_NR] = {0, "Identity Mapping"},
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[KERNEL_START_NR] = {(unsigned long)&_stext, "Kernel Image Start"},
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[KERNEL_END_NR] = {(unsigned long)&_end, "Kernel Image End"},
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[VMEMMAP_NR] = {0, "vmemmap Area"},
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[VMALLOC_NR] = {0, "vmalloc Area"},
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#ifdef CONFIG_64BIT
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[MODULES_NR] = {0, "Modules Area"},
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#endif
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{ -1, NULL }
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};
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struct pg_state {
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int level;
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unsigned int current_prot;
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unsigned long start_address;
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unsigned long current_address;
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const struct addr_marker *marker;
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};
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static void print_prot(struct seq_file *m, unsigned int pr, int level)
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{
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static const char * const level_name[] =
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{ "ASCE", "PGD", "PUD", "PMD", "PTE" };
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seq_printf(m, "%s ", level_name[level]);
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if (pr & _PAGE_INVALID) {
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seq_printf(m, "I\n");
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return;
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}
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seq_printf(m, "%s", pr & _PAGE_PROTECT ? "RO " : "RW ");
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seq_printf(m, "%s", pr & _PAGE_CO ? "CO " : " ");
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seq_putc(m, '\n');
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}
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static void note_page(struct seq_file *m, struct pg_state *st,
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unsigned int new_prot, int level)
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{
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static const char units[] = "KMGTPE";
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int width = sizeof(unsigned long) * 2;
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const char *unit = units;
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unsigned int prot, cur;
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unsigned long delta;
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/*
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* If we have a "break" in the series, we need to flush the state
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* that we have now. "break" is either changing perms, levels or
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* address space marker.
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*/
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prot = new_prot;
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cur = st->current_prot;
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if (!st->level) {
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/* First entry */
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st->current_prot = new_prot;
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st->level = level;
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st->marker = address_markers;
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seq_printf(m, "---[ %s ]---\n", st->marker->name);
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} else if (prot != cur || level != st->level ||
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st->current_address >= st->marker[1].start_address) {
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/* Print the actual finished series */
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seq_printf(m, "0x%0*lx-0x%0*lx",
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width, st->start_address,
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width, st->current_address);
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delta = (st->current_address - st->start_address) >> 10;
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while (!(delta & 0x3ff) && unit[1]) {
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delta >>= 10;
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unit++;
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}
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seq_printf(m, "%9lu%c ", delta, *unit);
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print_prot(m, st->current_prot, st->level);
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if (st->current_address >= st->marker[1].start_address) {
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st->marker++;
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seq_printf(m, "---[ %s ]---\n", st->marker->name);
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}
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st->start_address = st->current_address;
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st->current_prot = new_prot;
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st->level = level;
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}
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}
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/*
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* The actual page table walker functions. In order to keep the
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* implementation of print_prot() short, we only check and pass
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* _PAGE_INVALID and _PAGE_PROTECT flags to note_page() if a region,
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* segment or page table entry is invalid or read-only.
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* After all it's just a hint that the current level being walked
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* contains an invalid or read-only entry.
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*/
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static void walk_pte_level(struct seq_file *m, struct pg_state *st,
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pmd_t *pmd, unsigned long addr)
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{
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unsigned int prot;
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pte_t *pte;
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int i;
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for (i = 0; i < PTRS_PER_PTE && addr < max_addr; i++) {
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st->current_address = addr;
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pte = pte_offset_kernel(pmd, addr);
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prot = pte_val(*pte) & (_PAGE_PROTECT | _PAGE_INVALID);
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note_page(m, st, prot, 4);
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addr += PAGE_SIZE;
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}
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}
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#ifdef CONFIG_64BIT
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#define _PMD_PROT_MASK (_SEGMENT_ENTRY_PROTECT | _SEGMENT_ENTRY_CO)
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#else
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#define _PMD_PROT_MASK 0
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#endif
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static void walk_pmd_level(struct seq_file *m, struct pg_state *st,
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pud_t *pud, unsigned long addr)
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{
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unsigned int prot;
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pmd_t *pmd;
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int i;
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for (i = 0; i < PTRS_PER_PMD && addr < max_addr; i++) {
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st->current_address = addr;
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pmd = pmd_offset(pud, addr);
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if (!pmd_none(*pmd)) {
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if (pmd_large(*pmd)) {
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prot = pmd_val(*pmd) & _PMD_PROT_MASK;
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note_page(m, st, prot, 3);
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} else
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walk_pte_level(m, st, pmd, addr);
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} else
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note_page(m, st, _PAGE_INVALID, 3);
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addr += PMD_SIZE;
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}
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}
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#ifdef CONFIG_64BIT
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#define _PUD_PROT_MASK (_REGION3_ENTRY_RO | _REGION3_ENTRY_CO)
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#else
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#define _PUD_PROT_MASK 0
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#endif
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static void walk_pud_level(struct seq_file *m, struct pg_state *st,
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pgd_t *pgd, unsigned long addr)
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{
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unsigned int prot;
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pud_t *pud;
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int i;
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for (i = 0; i < PTRS_PER_PUD && addr < max_addr; i++) {
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st->current_address = addr;
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pud = pud_offset(pgd, addr);
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if (!pud_none(*pud))
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if (pud_large(*pud)) {
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prot = pud_val(*pud) & _PUD_PROT_MASK;
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note_page(m, st, prot, 2);
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} else
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walk_pmd_level(m, st, pud, addr);
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else
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note_page(m, st, _PAGE_INVALID, 2);
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addr += PUD_SIZE;
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}
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}
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static void walk_pgd_level(struct seq_file *m)
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{
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unsigned long addr = 0;
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struct pg_state st;
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pgd_t *pgd;
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int i;
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memset(&st, 0, sizeof(st));
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for (i = 0; i < PTRS_PER_PGD && addr < max_addr; i++) {
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st.current_address = addr;
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pgd = pgd_offset_k(addr);
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if (!pgd_none(*pgd))
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walk_pud_level(m, &st, pgd, addr);
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else
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note_page(m, &st, _PAGE_INVALID, 1);
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addr += PGDIR_SIZE;
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}
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/* Flush out the last page */
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st.current_address = max_addr;
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note_page(m, &st, 0, 0);
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}
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static int ptdump_show(struct seq_file *m, void *v)
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{
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walk_pgd_level(m);
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return 0;
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}
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static int ptdump_open(struct inode *inode, struct file *filp)
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{
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return single_open(filp, ptdump_show, NULL);
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}
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static const struct file_operations ptdump_fops = {
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.open = ptdump_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static int pt_dump_init(void)
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{
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/*
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* Figure out the maximum virtual address being accessible with the
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* kernel ASCE. We need this to keep the page table walker functions
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* from accessing non-existent entries.
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*/
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#ifdef CONFIG_32BIT
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max_addr = 1UL << 31;
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#else
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max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2;
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max_addr = 1UL << (max_addr * 11 + 31);
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address_markers[MODULES_NR].start_address = MODULES_VADDR;
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#endif
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address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap;
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address_markers[VMALLOC_NR].start_address = VMALLOC_START;
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debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops);
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return 0;
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}
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device_initcall(pt_dump_init);
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