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394 lines
8.7 KiB
394 lines
8.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (c) 2014, The Linux Foundation. All rights reserved. |
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* Debug helper to dump the current kernel pagetables of the system |
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* so that we can see what the various memory ranges are set to. |
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* |
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* Derived from x86 and arm implementation: |
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* (C) Copyright 2008 Intel Corporation |
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* |
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* Author: Arjan van de Ven <[email protected]> |
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*/ |
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#include <linux/debugfs.h> |
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#include <linux/errno.h> |
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#include <linux/fs.h> |
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#include <linux/io.h> |
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#include <linux/init.h> |
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#include <linux/mm.h> |
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#include <linux/ptdump.h> |
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#include <linux/sched.h> |
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#include <linux/seq_file.h> |
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#include <asm/fixmap.h> |
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#include <asm/kasan.h> |
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#include <asm/memory.h> |
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#include <asm/pgtable-hwdef.h> |
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#include <asm/ptdump.h> |
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enum address_markers_idx { |
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PAGE_OFFSET_NR = 0, |
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PAGE_END_NR, |
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#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) |
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KASAN_START_NR, |
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#endif |
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}; |
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static struct addr_marker address_markers[] = { |
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{ PAGE_OFFSET, "Linear Mapping start" }, |
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{ 0 /* PAGE_END */, "Linear Mapping end" }, |
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#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) |
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{ 0 /* KASAN_SHADOW_START */, "Kasan shadow start" }, |
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{ KASAN_SHADOW_END, "Kasan shadow end" }, |
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#endif |
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{ BPF_JIT_REGION_START, "BPF start" }, |
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{ BPF_JIT_REGION_END, "BPF end" }, |
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{ MODULES_VADDR, "Modules start" }, |
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{ MODULES_END, "Modules end" }, |
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{ VMALLOC_START, "vmalloc() area" }, |
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{ VMALLOC_END, "vmalloc() end" }, |
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{ FIXADDR_START, "Fixmap start" }, |
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{ FIXADDR_TOP, "Fixmap end" }, |
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{ PCI_IO_START, "PCI I/O start" }, |
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{ PCI_IO_END, "PCI I/O end" }, |
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#ifdef CONFIG_SPARSEMEM_VMEMMAP |
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{ VMEMMAP_START, "vmemmap start" }, |
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{ VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" }, |
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#endif |
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{ -1, NULL }, |
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}; |
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#define pt_dump_seq_printf(m, fmt, args...) \ |
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({ \ |
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if (m) \ |
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seq_printf(m, fmt, ##args); \ |
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}) |
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#define pt_dump_seq_puts(m, fmt) \ |
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({ \ |
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if (m) \ |
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seq_printf(m, fmt); \ |
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}) |
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/* |
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* The page dumper groups page table entries of the same type into a single |
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* description. It uses pg_state to track the range information while |
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* iterating over the pte entries. When the continuity is broken it then |
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* dumps out a description of the range. |
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*/ |
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struct pg_state { |
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struct ptdump_state ptdump; |
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struct seq_file *seq; |
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const struct addr_marker *marker; |
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unsigned long start_address; |
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int level; |
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u64 current_prot; |
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bool check_wx; |
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unsigned long wx_pages; |
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unsigned long uxn_pages; |
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}; |
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struct prot_bits { |
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u64 mask; |
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u64 val; |
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const char *set; |
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const char *clear; |
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}; |
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static const struct prot_bits pte_bits[] = { |
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{ |
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.mask = PTE_VALID, |
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.val = PTE_VALID, |
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.set = " ", |
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.clear = "F", |
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}, { |
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.mask = PTE_USER, |
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.val = PTE_USER, |
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.set = "USR", |
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.clear = " ", |
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}, { |
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.mask = PTE_RDONLY, |
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.val = PTE_RDONLY, |
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.set = "ro", |
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.clear = "RW", |
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}, { |
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.mask = PTE_PXN, |
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.val = PTE_PXN, |
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.set = "NX", |
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.clear = "x ", |
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}, { |
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.mask = PTE_SHARED, |
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.val = PTE_SHARED, |
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.set = "SHD", |
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.clear = " ", |
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}, { |
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.mask = PTE_AF, |
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.val = PTE_AF, |
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.set = "AF", |
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.clear = " ", |
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}, { |
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.mask = PTE_NG, |
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.val = PTE_NG, |
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.set = "NG", |
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.clear = " ", |
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}, { |
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.mask = PTE_CONT, |
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.val = PTE_CONT, |
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.set = "CON", |
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.clear = " ", |
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}, { |
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.mask = PTE_TABLE_BIT, |
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.val = PTE_TABLE_BIT, |
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.set = " ", |
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.clear = "BLK", |
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}, { |
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.mask = PTE_UXN, |
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.val = PTE_UXN, |
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.set = "UXN", |
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.clear = " ", |
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}, { |
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.mask = PTE_GP, |
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.val = PTE_GP, |
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.set = "GP", |
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.clear = " ", |
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}, { |
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.mask = PTE_ATTRINDX_MASK, |
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.val = PTE_ATTRINDX(MT_DEVICE_nGnRnE), |
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.set = "DEVICE/nGnRnE", |
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}, { |
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.mask = PTE_ATTRINDX_MASK, |
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.val = PTE_ATTRINDX(MT_DEVICE_nGnRE), |
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.set = "DEVICE/nGnRE", |
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}, { |
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.mask = PTE_ATTRINDX_MASK, |
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.val = PTE_ATTRINDX(MT_DEVICE_GRE), |
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.set = "DEVICE/GRE", |
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}, { |
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.mask = PTE_ATTRINDX_MASK, |
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.val = PTE_ATTRINDX(MT_NORMAL_NC), |
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.set = "MEM/NORMAL-NC", |
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}, { |
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.mask = PTE_ATTRINDX_MASK, |
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.val = PTE_ATTRINDX(MT_NORMAL), |
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.set = "MEM/NORMAL", |
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}, { |
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.mask = PTE_ATTRINDX_MASK, |
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.val = PTE_ATTRINDX(MT_NORMAL_TAGGED), |
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.set = "MEM/NORMAL-TAGGED", |
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} |
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}; |
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struct pg_level { |
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const struct prot_bits *bits; |
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const char *name; |
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size_t num; |
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u64 mask; |
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}; |
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static struct pg_level pg_level[] = { |
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{ /* pgd */ |
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.name = "PGD", |
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.bits = pte_bits, |
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.num = ARRAY_SIZE(pte_bits), |
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}, { /* p4d */ |
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.name = "P4D", |
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.bits = pte_bits, |
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.num = ARRAY_SIZE(pte_bits), |
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}, { /* pud */ |
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.name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD", |
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.bits = pte_bits, |
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.num = ARRAY_SIZE(pte_bits), |
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}, { /* pmd */ |
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.name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD", |
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.bits = pte_bits, |
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.num = ARRAY_SIZE(pte_bits), |
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}, { /* pte */ |
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.name = "PTE", |
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.bits = pte_bits, |
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.num = ARRAY_SIZE(pte_bits), |
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}, |
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}; |
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static void dump_prot(struct pg_state *st, const struct prot_bits *bits, |
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size_t num) |
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{ |
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unsigned i; |
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for (i = 0; i < num; i++, bits++) { |
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const char *s; |
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if ((st->current_prot & bits->mask) == bits->val) |
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s = bits->set; |
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else |
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s = bits->clear; |
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if (s) |
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pt_dump_seq_printf(st->seq, " %s", s); |
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} |
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} |
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static void note_prot_uxn(struct pg_state *st, unsigned long addr) |
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{ |
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if (!st->check_wx) |
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return; |
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if ((st->current_prot & PTE_UXN) == PTE_UXN) |
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return; |
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WARN_ONCE(1, "arm64/mm: Found non-UXN mapping at address %p/%pS\n", |
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(void *)st->start_address, (void *)st->start_address); |
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st->uxn_pages += (addr - st->start_address) / PAGE_SIZE; |
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} |
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static void note_prot_wx(struct pg_state *st, unsigned long addr) |
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{ |
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if (!st->check_wx) |
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return; |
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if ((st->current_prot & PTE_RDONLY) == PTE_RDONLY) |
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return; |
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if ((st->current_prot & PTE_PXN) == PTE_PXN) |
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return; |
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WARN_ONCE(1, "arm64/mm: Found insecure W+X mapping at address %p/%pS\n", |
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(void *)st->start_address, (void *)st->start_address); |
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st->wx_pages += (addr - st->start_address) / PAGE_SIZE; |
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} |
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static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, |
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u64 val) |
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{ |
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struct pg_state *st = container_of(pt_st, struct pg_state, ptdump); |
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static const char units[] = "KMGTPE"; |
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u64 prot = 0; |
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if (level >= 0) |
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prot = val & pg_level[level].mask; |
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if (st->level == -1) { |
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st->level = level; |
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st->current_prot = prot; |
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st->start_address = addr; |
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pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
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} else if (prot != st->current_prot || level != st->level || |
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addr >= st->marker[1].start_address) { |
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const char *unit = units; |
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unsigned long delta; |
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if (st->current_prot) { |
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note_prot_uxn(st, addr); |
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note_prot_wx(st, addr); |
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} |
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pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ", |
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st->start_address, addr); |
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delta = (addr - st->start_address) >> 10; |
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while (!(delta & 1023) && unit[1]) { |
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delta >>= 10; |
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unit++; |
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} |
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pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit, |
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pg_level[st->level].name); |
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if (st->current_prot && pg_level[st->level].bits) |
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dump_prot(st, pg_level[st->level].bits, |
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pg_level[st->level].num); |
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pt_dump_seq_puts(st->seq, "\n"); |
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if (addr >= st->marker[1].start_address) { |
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st->marker++; |
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pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
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} |
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st->start_address = addr; |
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st->current_prot = prot; |
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st->level = level; |
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} |
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if (addr >= st->marker[1].start_address) { |
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st->marker++; |
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pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
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} |
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} |
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void ptdump_walk(struct seq_file *s, struct ptdump_info *info) |
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{ |
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unsigned long end = ~0UL; |
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struct pg_state st; |
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if (info->base_addr < TASK_SIZE_64) |
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end = TASK_SIZE_64; |
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st = (struct pg_state){ |
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.seq = s, |
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.marker = info->markers, |
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.level = -1, |
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.ptdump = { |
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.note_page = note_page, |
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.range = (struct ptdump_range[]){ |
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{info->base_addr, end}, |
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{0, 0} |
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} |
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} |
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}; |
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ptdump_walk_pgd(&st.ptdump, info->mm, NULL); |
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} |
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static void ptdump_initialize(void) |
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{ |
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unsigned i, j; |
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for (i = 0; i < ARRAY_SIZE(pg_level); i++) |
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if (pg_level[i].bits) |
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for (j = 0; j < pg_level[i].num; j++) |
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pg_level[i].mask |= pg_level[i].bits[j].mask; |
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} |
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static struct ptdump_info kernel_ptdump_info = { |
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.mm = &init_mm, |
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.markers = address_markers, |
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.base_addr = PAGE_OFFSET, |
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}; |
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void ptdump_check_wx(void) |
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{ |
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struct pg_state st = { |
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.seq = NULL, |
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.marker = (struct addr_marker[]) { |
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{ 0, NULL}, |
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{ -1, NULL}, |
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}, |
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.level = -1, |
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.check_wx = true, |
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.ptdump = { |
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.note_page = note_page, |
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.range = (struct ptdump_range[]) { |
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{PAGE_OFFSET, ~0UL}, |
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{0, 0} |
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} |
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} |
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}; |
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ptdump_walk_pgd(&st.ptdump, &init_mm, NULL); |
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if (st.wx_pages || st.uxn_pages) |
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pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n", |
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st.wx_pages, st.uxn_pages); |
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else |
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pr_info("Checked W+X mappings: passed, no W+X pages found\n"); |
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} |
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static int ptdump_init(void) |
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{ |
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address_markers[PAGE_END_NR].start_address = PAGE_END; |
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#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) |
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address_markers[KASAN_START_NR].start_address = KASAN_SHADOW_START; |
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#endif |
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ptdump_initialize(); |
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ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables"); |
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return 0; |
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} |
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device_initcall(ptdump_init);
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