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Diffstat (limited to 'arch/x86/mm/dump_pagetables.c')
-rw-r--r--arch/x86/mm/dump_pagetables.c426
1 files changed, 426 insertions, 0 deletions
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
new file mode 100644
index 000000000..f0cedf339
--- /dev/null
+++ b/arch/x86/mm/dump_pagetables.c
@@ -0,0 +1,426 @@
+/*
+ * Debug helper to dump the current kernel pagetables of the system
+ * so that we can see what the various memory ranges are set to.
+ *
+ * (C) Copyright 2008 Intel Corporation
+ *
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+
+#include <asm/pgtable.h>
+
+/*
+ * The dumper groups pagetable entries of the same type into one, and for
+ * that it needs to keep some state when walking, and flush this state
+ * when a "break" in the continuity is found.
+ */
+struct pg_state {
+ int level;
+ pgprot_t current_prot;
+ unsigned long start_address;
+ unsigned long current_address;
+ const struct addr_marker *marker;
+ unsigned long lines;
+ bool to_dmesg;
+};
+
+struct addr_marker {
+ unsigned long start_address;
+ const char *name;
+ unsigned long max_lines;
+};
+
+/* indices for address_markers; keep sync'd w/ address_markers below */
+enum address_markers_idx {
+ USER_SPACE_NR = 0,
+#ifdef CONFIG_X86_64
+ KERNEL_SPACE_NR,
+ LOW_KERNEL_NR,
+ VMALLOC_START_NR,
+ VMEMMAP_START_NR,
+# ifdef CONFIG_X86_ESPFIX64
+ ESPFIX_START_NR,
+# endif
+ HIGH_KERNEL_NR,
+ MODULES_VADDR_NR,
+ MODULES_END_NR,
+#else
+ KERNEL_SPACE_NR,
+ VMALLOC_START_NR,
+ VMALLOC_END_NR,
+# ifdef CONFIG_HIGHMEM
+ PKMAP_BASE_NR,
+# endif
+ FIXADDR_START_NR,
+#endif
+};
+
+/* Address space markers hints */
+static struct addr_marker address_markers[] = {
+ { 0, "User Space" },
+#ifdef CONFIG_X86_64
+ { 0x8000000000000000UL, "Kernel Space" },
+ { PAGE_OFFSET, "Low Kernel Mapping" },
+ { VMALLOC_START, "vmalloc() Area" },
+ { VMEMMAP_START, "Vmemmap" },
+# ifdef CONFIG_X86_ESPFIX64
+ { ESPFIX_BASE_ADDR, "ESPfix Area", 16 },
+# endif
+# ifdef CONFIG_EFI
+ { EFI_VA_END, "EFI Runtime Services" },
+# endif
+ { __START_KERNEL_map, "High Kernel Mapping" },
+ { MODULES_VADDR, "Modules" },
+ { MODULES_END, "End Modules" },
+#else
+ { PAGE_OFFSET, "Kernel Mapping" },
+ { 0/* VMALLOC_START */, "vmalloc() Area" },
+ { 0/*VMALLOC_END*/, "vmalloc() End" },
+# ifdef CONFIG_HIGHMEM
+ { 0/*PKMAP_BASE*/, "Persisent kmap() Area" },
+# endif
+ { 0/*FIXADDR_START*/, "Fixmap Area" },
+#endif
+ { -1, NULL } /* End of list */
+};
+
+/* Multipliers for offsets within the PTEs */
+#define PTE_LEVEL_MULT (PAGE_SIZE)
+#define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
+#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
+#define PGD_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
+
+#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) \
+({ \
+ if (to_dmesg) \
+ printk(KERN_INFO fmt, ##args); \
+ else \
+ if (m) \
+ seq_printf(m, fmt, ##args); \
+})
+
+#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) \
+({ \
+ if (to_dmesg) \
+ printk(KERN_CONT fmt, ##args); \
+ else \
+ if (m) \
+ seq_printf(m, fmt, ##args); \
+})
+
+/*
+ * Print a readable form of a pgprot_t to the seq_file
+ */
+static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg)
+{
+ pgprotval_t pr = pgprot_val(prot);
+ static const char * const level_name[] =
+ { "cr3", "pgd", "pud", "pmd", "pte" };
+
+ if (!pgprot_val(prot)) {
+ /* Not present */
+ pt_dump_cont_printf(m, dmsg, " ");
+ } else {
+ if (pr & _PAGE_USER)
+ pt_dump_cont_printf(m, dmsg, "USR ");
+ else
+ pt_dump_cont_printf(m, dmsg, " ");
+ if (pr & _PAGE_RW)
+ pt_dump_cont_printf(m, dmsg, "RW ");
+ else
+ pt_dump_cont_printf(m, dmsg, "ro ");
+ if (pr & _PAGE_PWT)
+ pt_dump_cont_printf(m, dmsg, "PWT ");
+ else
+ pt_dump_cont_printf(m, dmsg, " ");
+ if (pr & _PAGE_PCD)
+ pt_dump_cont_printf(m, dmsg, "PCD ");
+ else
+ pt_dump_cont_printf(m, dmsg, " ");
+
+ /* Bit 7 has a different meaning on level 3 vs 4 */
+ if (level <= 3 && pr & _PAGE_PSE)
+ pt_dump_cont_printf(m, dmsg, "PSE ");
+ else
+ pt_dump_cont_printf(m, dmsg, " ");
+ if ((level == 4 && pr & _PAGE_PAT) ||
+ ((level == 3 || level == 2) && pr & _PAGE_PAT_LARGE))
+ pt_dump_cont_printf(m, dmsg, "pat ");
+ else
+ pt_dump_cont_printf(m, dmsg, " ");
+ if (pr & _PAGE_GLOBAL)
+ pt_dump_cont_printf(m, dmsg, "GLB ");
+ else
+ pt_dump_cont_printf(m, dmsg, " ");
+ if (pr & _PAGE_NX)
+ pt_dump_cont_printf(m, dmsg, "NX ");
+ else
+ pt_dump_cont_printf(m, dmsg, "x ");
+ }
+ pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]);
+}
+
+/*
+ * On 64 bits, sign-extend the 48 bit address to 64 bit
+ */
+static unsigned long normalize_addr(unsigned long u)
+{
+#ifdef CONFIG_X86_64
+ return (signed long)(u << 16) >> 16;
+#else
+ return u;
+#endif
+}
+
+/*
+ * This function gets called on a break in a continuous series
+ * of PTE entries; the next one is different so we need to
+ * print what we collected so far.
+ */
+static void note_page(struct seq_file *m, struct pg_state *st,
+ pgprot_t new_prot, int level)
+{
+ pgprotval_t prot, cur;
+ static const char units[] = "BKMGTPE";
+
+ /*
+ * If we have a "break" in the series, we need to flush the state that
+ * we have now. "break" is either changing perms, levels or
+ * address space marker.
+ */
+ prot = pgprot_val(new_prot) & PTE_FLAGS_MASK;
+ cur = pgprot_val(st->current_prot) & PTE_FLAGS_MASK;
+
+ if (!st->level) {
+ /* First entry */
+ st->current_prot = new_prot;
+ st->level = level;
+ st->marker = address_markers;
+ st->lines = 0;
+ pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
+ st->marker->name);
+ } else if (prot != cur || level != st->level ||
+ st->current_address >= st->marker[1].start_address) {
+ const char *unit = units;
+ unsigned long delta;
+ int width = sizeof(unsigned long) * 2;
+
+ /*
+ * Now print the actual finished series
+ */
+ if (!st->marker->max_lines ||
+ st->lines < st->marker->max_lines) {
+ pt_dump_seq_printf(m, st->to_dmesg,
+ "0x%0*lx-0x%0*lx ",
+ width, st->start_address,
+ width, st->current_address);
+
+ delta = st->current_address - st->start_address;
+ while (!(delta & 1023) && unit[1]) {
+ delta >>= 10;
+ unit++;
+ }
+ pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ",
+ delta, *unit);
+ printk_prot(m, st->current_prot, st->level,
+ st->to_dmesg);
+ }
+ st->lines++;
+
+ /*
+ * We print markers for special areas of address space,
+ * such as the start of vmalloc space etc.
+ * This helps in the interpretation.
+ */
+ if (st->current_address >= st->marker[1].start_address) {
+ if (st->marker->max_lines &&
+ st->lines > st->marker->max_lines) {
+ unsigned long nskip =
+ st->lines - st->marker->max_lines;
+ pt_dump_seq_printf(m, st->to_dmesg,
+ "... %lu entr%s skipped ... \n",
+ nskip,
+ nskip == 1 ? "y" : "ies");
+ }
+ st->marker++;
+ st->lines = 0;
+ pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
+ st->marker->name);
+ }
+
+ st->start_address = st->current_address;
+ st->current_prot = new_prot;
+ st->level = level;
+ }
+}
+
+static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr,
+ unsigned long P)
+{
+ int i;
+ pte_t *start;
+
+ start = (pte_t *) pmd_page_vaddr(addr);
+ for (i = 0; i < PTRS_PER_PTE; i++) {
+ pgprot_t prot = pte_pgprot(*start);
+
+ st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);
+ note_page(m, st, prot, 4);
+ start++;
+ }
+}
+
+#if PTRS_PER_PMD > 1
+
+static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr,
+ unsigned long P)
+{
+ int i;
+ pmd_t *start;
+
+ start = (pmd_t *) pud_page_vaddr(addr);
+ for (i = 0; i < PTRS_PER_PMD; i++) {
+ st->current_address = normalize_addr(P + i * PMD_LEVEL_MULT);
+ if (!pmd_none(*start)) {
+ pgprotval_t prot = pmd_val(*start) & PTE_FLAGS_MASK;
+
+ if (pmd_large(*start) || !pmd_present(*start))
+ note_page(m, st, __pgprot(prot), 3);
+ else
+ walk_pte_level(m, st, *start,
+ P + i * PMD_LEVEL_MULT);
+ } else
+ note_page(m, st, __pgprot(0), 3);
+ start++;
+ }
+}
+
+#else
+#define walk_pmd_level(m,s,a,p) walk_pte_level(m,s,__pmd(pud_val(a)),p)
+#define pud_large(a) pmd_large(__pmd(pud_val(a)))
+#define pud_none(a) pmd_none(__pmd(pud_val(a)))
+#endif
+
+#if PTRS_PER_PUD > 1
+
+static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
+ unsigned long P)
+{
+ int i;
+ pud_t *start;
+
+ start = (pud_t *) pgd_page_vaddr(addr);
+
+ for (i = 0; i < PTRS_PER_PUD; i++) {
+ st->current_address = normalize_addr(P + i * PUD_LEVEL_MULT);
+ if (!pud_none(*start)) {
+ pgprotval_t prot = pud_val(*start) & PTE_FLAGS_MASK;
+
+ if (pud_large(*start) || !pud_present(*start))
+ note_page(m, st, __pgprot(prot), 2);
+ else
+ walk_pmd_level(m, st, *start,
+ P + i * PUD_LEVEL_MULT);
+ } else
+ note_page(m, st, __pgprot(0), 2);
+
+ start++;
+ }
+}
+
+#else
+#define walk_pud_level(m,s,a,p) walk_pmd_level(m,s,__pud(pgd_val(a)),p)
+#define pgd_large(a) pud_large(__pud(pgd_val(a)))
+#define pgd_none(a) pud_none(__pud(pgd_val(a)))
+#endif
+
+void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
+{
+#ifdef CONFIG_X86_64
+ pgd_t *start = (pgd_t *) &init_level4_pgt;
+#else
+ pgd_t *start = swapper_pg_dir;
+#endif
+ int i;
+ struct pg_state st = {};
+
+ if (pgd) {
+ start = pgd;
+ st.to_dmesg = true;
+ }
+
+ for (i = 0; i < PTRS_PER_PGD; i++) {
+ st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
+ if (!pgd_none(*start)) {
+ pgprotval_t prot = pgd_val(*start) & PTE_FLAGS_MASK;
+
+ if (pgd_large(*start) || !pgd_present(*start))
+ note_page(m, &st, __pgprot(prot), 1);
+ else
+ walk_pud_level(m, &st, *start,
+ i * PGD_LEVEL_MULT);
+ } else
+ note_page(m, &st, __pgprot(0), 1);
+
+ start++;
+ }
+
+ /* Flush out the last page */
+ st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT);
+ note_page(m, &st, __pgprot(0), 0);
+}
+
+static int ptdump_show(struct seq_file *m, void *v)
+{
+ ptdump_walk_pgd_level(m, NULL);
+ return 0;
+}
+
+static int ptdump_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, ptdump_show, NULL);
+}
+
+static const struct file_operations ptdump_fops = {
+ .open = ptdump_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int pt_dump_init(void)
+{
+ struct dentry *pe;
+
+#ifdef CONFIG_X86_32
+ /* Not a compile-time constant on x86-32 */
+ address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
+ address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
+# ifdef CONFIG_HIGHMEM
+ address_markers[PKMAP_BASE_NR].start_address = PKMAP_BASE;
+# endif
+ address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
+#endif
+
+ pe = debugfs_create_file("kernel_page_tables", 0600, NULL, NULL,
+ &ptdump_fops);
+ if (!pe)
+ return -ENOMEM;
+
+ return 0;
+}
+
+__initcall(pt_dump_init);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
+MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-17 23:25:57 +0000