diff options
| -rw-r--r-- | arch/arm64/Kconfig.debug | 12 | ||||
| -rw-r--r-- | arch/arm64/mm/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm64/mm/dump.c | 332 |
3 files changed, 345 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index 0a12933e50ed..5fdd6dce8061 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -6,6 +6,18 @@ config FRAME_POINTER bool default y +config ARM64_PTDUMP + bool "Export kernel pagetable layout to userspace via debugfs" + depends on DEBUG_KERNEL + select DEBUG_FS + help + Say Y here if you want to show the kernel pagetable layout in a + debugfs file. This information is only useful for kernel developers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + If in doubt, say "N" + config STRICT_DEVMEM bool "Filter access to /dev/mem" depends on MMU diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index c56179ed2c09..773d37a14039 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -3,3 +3,4 @@ obj-y := dma-mapping.o extable.o fault.o init.o \ ioremap.o mmap.o pgd.o mmu.o \ context.o proc.o pageattr.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o +obj-$(CONFIG_ARM64_PTDUMP) += dump.o diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c new file mode 100644 index 000000000000..bf69601be546 --- /dev/null +++ b/arch/arm64/mm/dump.c @@ -0,0 +1,332 @@ +/* + * Copyright (c) 2014, The Linux Foundation. All rights reserved. + * Debug helper to dump the current kernel pagetables of the system + * so that we can see what the various memory ranges are set to. + * + * Derived from x86 and arm implementation: + * (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/fs.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/seq_file.h> + +#include <asm/fixmap.h> +#include <asm/pgtable.h> + +#define LOWEST_ADDR (UL(0xffffffffffffffff) << VA_BITS) + +struct addr_marker { + unsigned long start_address; + const char *name; +}; + +enum address_markers_idx { + VMALLOC_START_NR = 0, + VMALLOC_END_NR, +#ifdef CONFIG_SPARSEMEM_VMEMMAP + VMEMMAP_START_NR, + VMEMMAP_END_NR, +#endif + PCI_START_NR, + PCI_END_NR, + FIXADDR_START_NR, + FIXADDR_END_NR, + MODULES_START_NR, + MODUELS_END_NR, + KERNEL_SPACE_NR, +}; + +static struct addr_marker address_markers[] = { + { VMALLOC_START, "vmalloc() Area" }, + { VMALLOC_END, "vmalloc() End" }, +#ifdef CONFIG_SPARSEMEM_VMEMMAP + { 0, "vmemmap start" }, + { 0, "vmemmap end" }, +#endif + { (unsigned long) PCI_IOBASE, "PCI I/O start" }, + { (unsigned long) PCI_IOBASE + SZ_16M, "PCI I/O end" }, + { FIXADDR_START, "Fixmap start" }, + { FIXADDR_TOP, "Fixmap end" }, + { MODULES_VADDR, "Modules start" }, + { MODULES_END, "Modules end" }, + { PAGE_OFFSET, "Kernel Mapping" }, + { -1, NULL }, +}; + +struct pg_state { + struct seq_file *seq; + const struct addr_marker *marker; + unsigned long start_address; + unsigned level; + u64 current_prot; +}; + +struct prot_bits { + u64 mask; + u64 val; + const char *set; + const char *clear; +}; + +static const struct prot_bits pte_bits[] = { + { + .mask = PTE_USER, + .val = PTE_USER, + .set = "USR", + .clear = " ", + }, { + .mask = PTE_RDONLY, + .val = PTE_RDONLY, + .set = "ro", + .clear = "RW", + }, { + .mask = PTE_PXN, + .val = PTE_PXN, + .set = "NX", + .clear = "x ", + }, { + .mask = PTE_SHARED, + .val = PTE_SHARED, + .set = "SHD", + .clear = " ", + }, { + .mask = PTE_AF, + .val = PTE_AF, + .set = "AF", + .clear = " ", + }, { + .mask = PTE_NG, + .val = PTE_NG, + .set = "NG", + .clear = " ", + }, { + .mask = PTE_UXN, + .val = PTE_UXN, + .set = "UXN", + }, { + .mask = PTE_ATTRINDX_MASK, + .val = PTE_ATTRINDX(MT_DEVICE_nGnRnE), + .set = "DEVICE/nGnRnE", + }, { + .mask = PTE_ATTRINDX_MASK, + .val = PTE_ATTRINDX(MT_DEVICE_nGnRE), + .set = "DEVICE/nGnRE", + }, { + .mask = PTE_ATTRINDX_MASK, + .val = PTE_ATTRINDX(MT_DEVICE_GRE), + .set = "DEVICE/GRE", + }, { + .mask = PTE_ATTRINDX_MASK, + .val = PTE_ATTRINDX(MT_NORMAL_NC), + .set = "MEM/NORMAL-NC", + }, { + .mask = PTE_ATTRINDX_MASK, + .val = PTE_ATTRINDX(MT_NORMAL), + .set = "MEM/NORMAL", + } +}; + +struct pg_level { + const struct prot_bits *bits; + size_t num; + u64 mask; +}; + +static struct pg_level pg_level[] = { + { + }, { /* pgd */ + .bits = pte_bits, + .num = ARRAY_SIZE(pte_bits), + }, { /* pud */ + .bits = pte_bits, + .num = ARRAY_SIZE(pte_bits), + }, { /* pmd */ + .bits = pte_bits, + .num = ARRAY_SIZE(pte_bits), + }, { /* pte */ + .bits = pte_bits, + .num = ARRAY_SIZE(pte_bits), + }, +}; + +static void dump_prot(struct pg_state *st, const struct prot_bits *bits, + size_t num) +{ + unsigned i; + + for (i = 0; i < num; i++, bits++) { + const char *s; + + if ((st->current_prot & bits->mask) == bits->val) + s = bits->set; + else + s = bits->clear; + + if (s) + seq_printf(st->seq, " %s", s); + } +} + +static void note_page(struct pg_state *st, unsigned long addr, unsigned level, + u64 val) +{ + static const char units[] = "KMGTPE"; + u64 prot = val & pg_level[level].mask; + + if (addr < LOWEST_ADDR) + return; + + if (!st->level) { + st->level = level; + st->current_prot = prot; + st->start_address = addr; + seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + } else if (prot != st->current_prot || level != st->level || + addr >= st->marker[1].start_address) { + const char *unit = units; + unsigned long delta; + + if (st->current_prot) { + seq_printf(st->seq, "0x%16lx-0x%16lx ", + st->start_address, addr); + + delta = (addr - st->start_address) >> 10; + while (!(delta & 1023) && unit[1]) { + delta >>= 10; + unit++; + } + seq_printf(st->seq, "%9lu%c", delta, *unit); + if (pg_level[st->level].bits) + dump_prot(st, pg_level[st->level].bits, + pg_level[st->level].num); + seq_puts(st->seq, "\n"); + } + + if (addr >= st->marker[1].start_address) { + st->marker++; + seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + } + + st->start_address = addr; + st->current_prot = prot; + st->level = level; + } + + if (addr >= st->marker[1].start_address) { + st->marker++; + seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + } + +} + +static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start) +{ + pte_t *pte = pte_offset_kernel(pmd, 0); + unsigned long addr; + unsigned i; + + for (i = 0; i < PTRS_PER_PTE; i++, pte++) { + addr = start + i * PAGE_SIZE; + note_page(st, addr, 4, pte_val(*pte)); + } +} + +static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start) +{ + pmd_t *pmd = pmd_offset(pud, 0); + unsigned long addr; + unsigned i; + + for (i = 0; i < PTRS_PER_PMD; i++, pmd++) { + addr = start + i * PMD_SIZE; + if (pmd_none(*pmd) || pmd_sect(*pmd) || pmd_bad(*pmd)) + note_page(st, addr, 3, pmd_val(*pmd)); + else + walk_pte(st, pmd, addr); + } +} + +static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start) +{ + pud_t *pud = pud_offset(pgd, 0); + unsigned long addr; + unsigned i; + + for (i = 0; i < PTRS_PER_PUD; i++, pud++) { + addr = start + i * PUD_SIZE; + if (pud_none(*pud) || pud_sect(*pud) || pud_bad(*pud)) + note_page(st, addr, 2, pud_val(*pud)); + else + walk_pmd(st, pud, addr); + } +} + +static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start) +{ + pgd_t *pgd = pgd_offset(mm, 0); + unsigned i; + unsigned long addr; + + for (i = 0; i < PTRS_PER_PGD; i++, pgd++) { + addr = start + i * PGDIR_SIZE; + if (pgd_none(*pgd) || pgd_bad(*pgd)) + note_page(st, addr, 1, pgd_val(*pgd)); + else + walk_pud(st, pgd, addr); + } +} + +static int ptdump_show(struct seq_file *m, void *v) +{ + struct pg_state st = { + .seq = m, + .marker = address_markers, + }; + + walk_pgd(&st, &init_mm, LOWEST_ADDR); + + note_page(&st, 0, 0, 0); + return 0; +} + +static int ptdump_open(struct inode *inode, struct file *file) +{ + return single_open(file, ptdump_show, NULL); +} + +static const struct file_operations ptdump_fops = { + .open = ptdump_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int ptdump_init(void) +{ + struct dentry *pe; + unsigned i, j; + + for (i = 0; i < ARRAY_SIZE(pg_level); i++) + if (pg_level[i].bits) + for (j = 0; j < pg_level[i].num; j++) + pg_level[i].mask |= pg_level[i].bits[j].mask; + + address_markers[VMEMMAP_START_NR].start_address = + (unsigned long)virt_to_page(PAGE_OFFSET); + address_markers[VMEMMAP_END_NR].start_address = + (unsigned long)virt_to_page(high_memory); + + pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, + &ptdump_fops); + return pe ? 0 : -ENOMEM; +} +device_initcall(ptdump_init); |