diff options
Diffstat (limited to 'arch/riscv/mm/ptdump.c')
| -rw-r--r-- | arch/riscv/mm/ptdump.c | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c new file mode 100644 index 000000000000..1289cc6d3700 --- /dev/null +++ b/arch/riscv/mm/ptdump.c @@ -0,0 +1,424 @@ +// 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/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) +{ + ptdump_walk(m, m->private); + + 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); |