| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2019 SiFive |
| */ |
| |
| #include <linux/efi.h> |
| #include <linux/init.h> |
| #include <linux/debugfs.h> |
| #include <linux/memory_hotplug.h> |
| #include <linux/seq_file.h> |
| #include <linux/ptdump.h> |
| |
| #include <linux/pgtable.h> |
| #include <asm/kasan.h> |
| |
| #define pt_dump_seq_printf(m, fmt, args...) \ |
| ({ \ |
| if (m) \ |
| seq_printf(m, fmt, ##args); \ |
| }) |
| |
| #define pt_dump_seq_puts(m, fmt) \ |
| ({ \ |
| if (m) \ |
| seq_printf(m, fmt); \ |
| }) |
| |
| /* |
| * The page dumper groups page table entries of the same type into a single |
| * description. It uses pg_state to track the range information while |
| * iterating over the pte entries. When the continuity is broken it then |
| * dumps out a description of the range. |
| */ |
| struct pg_state { |
| struct ptdump_state ptdump; |
| struct seq_file *seq; |
| const struct addr_marker *marker; |
| unsigned long start_address; |
| unsigned long start_pa; |
| unsigned long last_pa; |
| int level; |
| u64 current_prot; |
| bool check_wx; |
| unsigned long wx_pages; |
| }; |
| |
| /* Address marker */ |
| struct addr_marker { |
| unsigned long start_address; |
| const char *name; |
| }; |
| |
| /* Private information for debugfs */ |
| struct ptd_mm_info { |
| struct mm_struct *mm; |
| const struct addr_marker *markers; |
| unsigned long base_addr; |
| unsigned long end; |
| }; |
| |
| enum address_markers_idx { |
| FIXMAP_START_NR, |
| FIXMAP_END_NR, |
| PCI_IO_START_NR, |
| PCI_IO_END_NR, |
| #ifdef CONFIG_SPARSEMEM_VMEMMAP |
| VMEMMAP_START_NR, |
| VMEMMAP_END_NR, |
| #endif |
| VMALLOC_START_NR, |
| VMALLOC_END_NR, |
| PAGE_OFFSET_NR, |
| #ifdef CONFIG_KASAN |
| KASAN_SHADOW_START_NR, |
| KASAN_SHADOW_END_NR, |
| #endif |
| #ifdef CONFIG_64BIT |
| MODULES_MAPPING_NR, |
| KERNEL_MAPPING_NR, |
| #endif |
| END_OF_SPACE_NR |
| }; |
| |
| static struct addr_marker address_markers[] = { |
| {0, "Fixmap start"}, |
| {0, "Fixmap end"}, |
| {0, "PCI I/O start"}, |
| {0, "PCI I/O end"}, |
| #ifdef CONFIG_SPARSEMEM_VMEMMAP |
| {0, "vmemmap start"}, |
| {0, "vmemmap end"}, |
| #endif |
| {0, "vmalloc() area"}, |
| {0, "vmalloc() end"}, |
| {0, "Linear mapping"}, |
| #ifdef CONFIG_KASAN |
| {0, "Kasan shadow start"}, |
| {0, "Kasan shadow end"}, |
| #endif |
| #ifdef CONFIG_64BIT |
| {0, "Modules/BPF mapping"}, |
| {0, "Kernel mapping"}, |
| #endif |
| {-1, NULL}, |
| }; |
| |
| static struct ptd_mm_info kernel_ptd_info = { |
| .mm = &init_mm, |
| .markers = address_markers, |
| .base_addr = 0, |
| .end = ULONG_MAX, |
| }; |
| |
| #ifdef CONFIG_EFI |
| static struct addr_marker efi_addr_markers[] = { |
| { 0, "UEFI runtime start" }, |
| { SZ_1G, "UEFI runtime end" }, |
| { -1, NULL } |
| }; |
| |
| static struct ptd_mm_info efi_ptd_info = { |
| .mm = &efi_mm, |
| .markers = efi_addr_markers, |
| .base_addr = 0, |
| .end = SZ_2G, |
| }; |
| #endif |
| |
| /* Page Table Entry */ |
| struct prot_bits { |
| u64 mask; |
| const char *set; |
| const char *clear; |
| }; |
| |
| static const struct prot_bits pte_bits[] = { |
| { |
| #ifdef CONFIG_64BIT |
| .mask = _PAGE_NAPOT, |
| .set = "N", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_MTMASK_SVPBMT, |
| .set = "MT(%s)", |
| .clear = " .. ", |
| }, { |
| #endif |
| .mask = _PAGE_SOFT, |
| .set = "RSW(%d)", |
| .clear = " .. ", |
| }, { |
| .mask = _PAGE_DIRTY, |
| .set = "D", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_ACCESSED, |
| .set = "A", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_GLOBAL, |
| .set = "G", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_USER, |
| .set = "U", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_EXEC, |
| .set = "X", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_WRITE, |
| .set = "W", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_READ, |
| .set = "R", |
| .clear = ".", |
| }, { |
| .mask = _PAGE_PRESENT, |
| .set = "V", |
| .clear = ".", |
| } |
| }; |
| |
| /* Page Level */ |
| struct pg_level { |
| const char *name; |
| u64 mask; |
| }; |
| |
| static struct pg_level pg_level[] = { |
| { /* pgd */ |
| .name = "PGD", |
| }, { /* p4d */ |
| .name = (CONFIG_PGTABLE_LEVELS > 4) ? "P4D" : "PGD", |
| }, { /* pud */ |
| .name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD", |
| }, { /* pmd */ |
| .name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD", |
| }, { /* pte */ |
| .name = "PTE", |
| }, |
| }; |
| |
| static void dump_prot(struct pg_state *st) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < ARRAY_SIZE(pte_bits); i++) { |
| char s[7]; |
| unsigned long val; |
| |
| val = st->current_prot & pte_bits[i].mask; |
| if (val) { |
| if (pte_bits[i].mask == _PAGE_SOFT) |
| sprintf(s, pte_bits[i].set, val >> 8); |
| #ifdef CONFIG_64BIT |
| else if (pte_bits[i].mask == _PAGE_MTMASK_SVPBMT) { |
| if (val == _PAGE_NOCACHE_SVPBMT) |
| sprintf(s, pte_bits[i].set, "NC"); |
| else if (val == _PAGE_IO_SVPBMT) |
| sprintf(s, pte_bits[i].set, "IO"); |
| else |
| sprintf(s, pte_bits[i].set, "??"); |
| } |
| #endif |
| else |
| sprintf(s, "%s", pte_bits[i].set); |
| } else { |
| sprintf(s, "%s", pte_bits[i].clear); |
| } |
| |
| pt_dump_seq_printf(st->seq, " %s", s); |
| } |
| } |
| |
| #ifdef CONFIG_64BIT |
| #define ADDR_FORMAT "0x%016lx" |
| #else |
| #define ADDR_FORMAT "0x%08lx" |
| #endif |
| static void dump_addr(struct pg_state *st, unsigned long addr) |
| { |
| static const char units[] = "KMGTPE"; |
| const char *unit = units; |
| unsigned long delta; |
| |
| pt_dump_seq_printf(st->seq, ADDR_FORMAT "-" ADDR_FORMAT " ", |
| st->start_address, addr); |
| |
| pt_dump_seq_printf(st->seq, " " ADDR_FORMAT " ", st->start_pa); |
| delta = (addr - st->start_address) >> 10; |
| |
| while (!(delta & 1023) && unit[1]) { |
| delta >>= 10; |
| unit++; |
| } |
| |
| pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit, |
| pg_level[st->level].name); |
| } |
| |
| static void note_prot_wx(struct pg_state *st, unsigned long addr) |
| { |
| if (!st->check_wx) |
| return; |
| |
| if ((st->current_prot & (_PAGE_WRITE | _PAGE_EXEC)) != |
| (_PAGE_WRITE | _PAGE_EXEC)) |
| return; |
| |
| WARN_ONCE(1, "riscv/mm: Found insecure W+X mapping at address %p/%pS\n", |
| (void *)st->start_address, (void *)st->start_address); |
| |
| st->wx_pages += (addr - st->start_address) / PAGE_SIZE; |
| } |
| |
| static void note_page(struct ptdump_state *pt_st, unsigned long addr, |
| int level, u64 val) |
| { |
| struct pg_state *st = container_of(pt_st, struct pg_state, ptdump); |
| u64 pa = PFN_PHYS(pte_pfn(__pte(val))); |
| u64 prot = 0; |
| |
| if (level >= 0) |
| prot = val & pg_level[level].mask; |
| |
| if (st->level == -1) { |
| st->level = level; |
| st->current_prot = prot; |
| st->start_address = addr; |
| st->start_pa = pa; |
| st->last_pa = pa; |
| pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
| } else if (prot != st->current_prot || |
| level != st->level || addr >= st->marker[1].start_address) { |
| if (st->current_prot) { |
| note_prot_wx(st, addr); |
| dump_addr(st, addr); |
| dump_prot(st); |
| pt_dump_seq_puts(st->seq, "\n"); |
| } |
| |
| while (addr >= st->marker[1].start_address) { |
| st->marker++; |
| pt_dump_seq_printf(st->seq, "---[ %s ]---\n", |
| st->marker->name); |
| } |
| |
| st->start_address = addr; |
| st->start_pa = pa; |
| st->last_pa = pa; |
| st->current_prot = prot; |
| st->level = level; |
| } else { |
| st->last_pa = pa; |
| } |
| } |
| |
| static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo) |
| { |
| struct pg_state st = { |
| .seq = s, |
| .marker = pinfo->markers, |
| .level = -1, |
| .ptdump = { |
| .note_page = note_page, |
| .range = (struct ptdump_range[]) { |
| {pinfo->base_addr, pinfo->end}, |
| {0, 0} |
| } |
| } |
| }; |
| |
| ptdump_walk_pgd(&st.ptdump, pinfo->mm, NULL); |
| } |
| |
| bool ptdump_check_wx(void) |
| { |
| struct pg_state st = { |
| .seq = NULL, |
| .marker = (struct addr_marker[]) { |
| {0, NULL}, |
| {-1, NULL}, |
| }, |
| .level = -1, |
| .check_wx = true, |
| .ptdump = { |
| .note_page = note_page, |
| .range = (struct ptdump_range[]) { |
| {KERN_VIRT_START, ULONG_MAX}, |
| {0, 0} |
| } |
| } |
| }; |
| |
| ptdump_walk_pgd(&st.ptdump, &init_mm, NULL); |
| |
| if (st.wx_pages) { |
| pr_warn("Checked W+X mappings: failed, %lu W+X pages found\n", |
| st.wx_pages); |
| |
| return false; |
| } else { |
| pr_info("Checked W+X mappings: passed, no W+X pages found\n"); |
| |
| return true; |
| } |
| } |
| |
| static int ptdump_show(struct seq_file *m, void *v) |
| { |
| get_online_mems(); |
| ptdump_walk(m, m->private); |
| put_online_mems(); |
| |
| return 0; |
| } |
| |
| DEFINE_SHOW_ATTRIBUTE(ptdump); |
| |
| static int __init ptdump_init(void) |
| { |
| unsigned int i, j; |
| |
| address_markers[FIXMAP_START_NR].start_address = FIXADDR_START; |
| address_markers[FIXMAP_END_NR].start_address = FIXADDR_TOP; |
| address_markers[PCI_IO_START_NR].start_address = PCI_IO_START; |
| address_markers[PCI_IO_END_NR].start_address = PCI_IO_END; |
| #ifdef CONFIG_SPARSEMEM_VMEMMAP |
| address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START; |
| address_markers[VMEMMAP_END_NR].start_address = VMEMMAP_END; |
| #endif |
| address_markers[VMALLOC_START_NR].start_address = VMALLOC_START; |
| address_markers[VMALLOC_END_NR].start_address = VMALLOC_END; |
| address_markers[PAGE_OFFSET_NR].start_address = PAGE_OFFSET; |
| #ifdef CONFIG_KASAN |
| address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START; |
| address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END; |
| #endif |
| #ifdef CONFIG_64BIT |
| address_markers[MODULES_MAPPING_NR].start_address = MODULES_VADDR; |
| address_markers[KERNEL_MAPPING_NR].start_address = kernel_map.virt_addr; |
| #endif |
| |
| kernel_ptd_info.base_addr = KERN_VIRT_START; |
| |
| pg_level[1].name = pgtable_l5_enabled ? "P4D" : "PGD"; |
| pg_level[2].name = pgtable_l4_enabled ? "PUD" : "PGD"; |
| |
| for (i = 0; i < ARRAY_SIZE(pg_level); i++) |
| for (j = 0; j < ARRAY_SIZE(pte_bits); j++) |
| pg_level[i].mask |= pte_bits[j].mask; |
| |
| debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info, |
| &ptdump_fops); |
| #ifdef CONFIG_EFI |
| if (efi_enabled(EFI_RUNTIME_SERVICES)) |
| debugfs_create_file("efi_page_tables", 0400, NULL, &efi_ptd_info, |
| &ptdump_fops); |
| #endif |
| |
| return 0; |
| } |
| |
| device_initcall(ptdump_init); |