403 lines
8.4 KiB
C
403 lines
8.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2019 SiFive
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*/
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#include <linux/efi.h>
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#include <linux/init.h>
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#include <linux/debugfs.h>
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#include <linux/seq_file.h>
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#include <linux/ptdump.h>
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#include <asm/ptdump.h>
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#include <linux/pgtable.h>
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#include <asm/kasan.h>
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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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unsigned long start_pa;
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unsigned long last_pa;
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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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};
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/* Address marker */
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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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/* Private information for debugfs */
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struct ptd_mm_info {
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struct mm_struct *mm;
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const struct addr_marker *markers;
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unsigned long base_addr;
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unsigned long end;
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};
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enum address_markers_idx {
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FIXMAP_START_NR,
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FIXMAP_END_NR,
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PCI_IO_START_NR,
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PCI_IO_END_NR,
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#ifdef CONFIG_SPARSEMEM_VMEMMAP
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VMEMMAP_START_NR,
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VMEMMAP_END_NR,
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#endif
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VMALLOC_START_NR,
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VMALLOC_END_NR,
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PAGE_OFFSET_NR,
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#ifdef CONFIG_KASAN
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KASAN_SHADOW_START_NR,
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KASAN_SHADOW_END_NR,
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#endif
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#ifdef CONFIG_64BIT
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MODULES_MAPPING_NR,
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KERNEL_MAPPING_NR,
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#endif
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END_OF_SPACE_NR
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};
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static struct addr_marker address_markers[] = {
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{0, "Fixmap start"},
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{0, "Fixmap end"},
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{0, "PCI I/O start"},
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{0, "PCI I/O end"},
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#ifdef CONFIG_SPARSEMEM_VMEMMAP
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{0, "vmemmap start"},
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{0, "vmemmap end"},
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#endif
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{0, "vmalloc() area"},
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{0, "vmalloc() end"},
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{0, "Linear mapping"},
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#ifdef CONFIG_KASAN
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{0, "Kasan shadow start"},
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{0, "Kasan shadow end"},
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#endif
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#ifdef CONFIG_64BIT
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{0, "Modules/BPF mapping"},
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{0, "Kernel mapping"},
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#endif
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{-1, NULL},
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};
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static struct ptd_mm_info kernel_ptd_info = {
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.mm = &init_mm,
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.markers = address_markers,
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.base_addr = 0,
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.end = ULONG_MAX,
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};
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#ifdef CONFIG_EFI
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static struct addr_marker efi_addr_markers[] = {
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{ 0, "UEFI runtime start" },
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{ SZ_1G, "UEFI runtime end" },
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{ -1, NULL }
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};
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static struct ptd_mm_info efi_ptd_info = {
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.mm = &efi_mm,
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.markers = efi_addr_markers,
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.base_addr = 0,
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.end = SZ_2G,
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};
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#endif
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/* Page Table Entry */
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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 = _PAGE_SOFT,
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.val = _PAGE_SOFT,
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.set = "RSW",
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.clear = " ",
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}, {
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.mask = _PAGE_DIRTY,
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.val = _PAGE_DIRTY,
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.set = "D",
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.clear = ".",
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}, {
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.mask = _PAGE_ACCESSED,
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.val = _PAGE_ACCESSED,
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.set = "A",
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.clear = ".",
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}, {
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.mask = _PAGE_GLOBAL,
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.val = _PAGE_GLOBAL,
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.set = "G",
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.clear = ".",
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}, {
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.mask = _PAGE_USER,
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.val = _PAGE_USER,
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.set = "U",
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.clear = ".",
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}, {
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.mask = _PAGE_EXEC,
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.val = _PAGE_EXEC,
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.set = "X",
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.clear = ".",
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}, {
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.mask = _PAGE_WRITE,
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.val = _PAGE_WRITE,
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.set = "W",
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.clear = ".",
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}, {
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.mask = _PAGE_READ,
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.val = _PAGE_READ,
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.set = "R",
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.clear = ".",
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}, {
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.mask = _PAGE_PRESENT,
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.val = _PAGE_PRESENT,
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.set = "V",
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.clear = ".",
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}
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};
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/* Page Level */
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struct pg_level {
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const char *name;
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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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}, { /* p4d */
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.name = (CONFIG_PGTABLE_LEVELS > 4) ? "P4D" : "PGD",
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}, { /* pud */
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.name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
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}, { /* pmd */
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.name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD",
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}, { /* pte */
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.name = "PTE",
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},
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};
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static void dump_prot(struct pg_state *st)
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{
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(pte_bits); i++) {
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const char *s;
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if ((st->current_prot & pte_bits[i].mask) == pte_bits[i].val)
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s = pte_bits[i].set;
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else
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s = pte_bits[i].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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#ifdef CONFIG_64BIT
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#define ADDR_FORMAT "0x%016lx"
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#else
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#define ADDR_FORMAT "0x%08lx"
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#endif
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static void dump_addr(struct pg_state *st, unsigned long addr)
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{
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static const char units[] = "KMGTPE";
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const char *unit = units;
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unsigned long delta;
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pt_dump_seq_printf(st->seq, ADDR_FORMAT "-" ADDR_FORMAT " ",
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st->start_address, addr);
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pt_dump_seq_printf(st->seq, " " ADDR_FORMAT " ", st->start_pa);
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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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}
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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 & (_PAGE_WRITE | _PAGE_EXEC)) !=
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(_PAGE_WRITE | _PAGE_EXEC))
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return;
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WARN_ONCE(1, "riscv/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,
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int level, 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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u64 pa = PFN_PHYS(pte_pfn(__pte(val)));
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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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st->start_pa = pa;
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st->last_pa = pa;
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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 ||
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level != st->level || addr >= st->marker[1].start_address) {
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if (st->current_prot) {
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note_prot_wx(st, addr);
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dump_addr(st, addr);
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dump_prot(st);
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pt_dump_seq_puts(st->seq, "\n");
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}
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while (addr >= st->marker[1].start_address) {
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st->marker++;
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pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
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st->marker->name);
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}
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st->start_address = addr;
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st->start_pa = pa;
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st->last_pa = pa;
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st->current_prot = prot;
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st->level = level;
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} else {
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st->last_pa = pa;
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}
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}
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static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo)
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{
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struct pg_state st = {
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.seq = s,
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.marker = pinfo->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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{pinfo->base_addr, pinfo->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, pinfo->mm, NULL);
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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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{KERN_VIRT_START, ULONG_MAX},
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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)
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pr_warn("Checked W+X mappings: failed, %lu W+X pages found\n",
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st.wx_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_show(struct seq_file *m, void *v)
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{
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ptdump_walk(m, m->private);
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(ptdump);
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static int __init ptdump_init(void)
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{
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unsigned int i, j;
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address_markers[FIXMAP_START_NR].start_address = FIXADDR_START;
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address_markers[FIXMAP_END_NR].start_address = FIXADDR_TOP;
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address_markers[PCI_IO_START_NR].start_address = PCI_IO_START;
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address_markers[PCI_IO_END_NR].start_address = PCI_IO_END;
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#ifdef CONFIG_SPARSEMEM_VMEMMAP
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address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
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address_markers[VMEMMAP_END_NR].start_address = VMEMMAP_END;
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#endif
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address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
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address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
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address_markers[PAGE_OFFSET_NR].start_address = PAGE_OFFSET;
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#ifdef CONFIG_KASAN
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address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
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address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
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#endif
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#ifdef CONFIG_64BIT
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address_markers[MODULES_MAPPING_NR].start_address = MODULES_VADDR;
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address_markers[KERNEL_MAPPING_NR].start_address = kernel_map.virt_addr;
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#endif
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kernel_ptd_info.base_addr = KERN_VIRT_START;
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for (i = 0; i < ARRAY_SIZE(pg_level); i++)
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for (j = 0; j < ARRAY_SIZE(pte_bits); j++)
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pg_level[i].mask |= pte_bits[j].mask;
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debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info,
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&ptdump_fops);
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#ifdef CONFIG_EFI
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if (efi_enabled(EFI_RUNTIME_SERVICES))
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debugfs_create_file("efi_page_tables", 0400, NULL, &efi_ptd_info,
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&ptdump_fops);
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#endif
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return 0;
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}
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device_initcall(ptdump_init);
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