summaryrefslogtreecommitdiffstats
path: root/arch/riscv/mm/ptdump.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/riscv/mm/ptdump.c')
-rw-r--r--arch/riscv/mm/ptdump.c405
1 files changed, 405 insertions, 0 deletions
diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c
new file mode 100644
index 0000000000..e9090b38f8
--- /dev/null
+++ b/arch/riscv/mm/ptdump.c
@@ -0,0 +1,405 @@
+// 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 <asm/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;
+ u64 val;
+ const char *set;
+ const char *clear;
+};
+
+static const struct prot_bits pte_bits[] = {
+ {
+ .mask = _PAGE_SOFT,
+ .val = _PAGE_SOFT,
+ .set = "RSW",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_DIRTY,
+ .val = _PAGE_DIRTY,
+ .set = "D",
+ .clear = ".",
+ }, {
+ .mask = _PAGE_ACCESSED,
+ .val = _PAGE_ACCESSED,
+ .set = "A",
+ .clear = ".",
+ }, {
+ .mask = _PAGE_GLOBAL,
+ .val = _PAGE_GLOBAL,
+ .set = "G",
+ .clear = ".",
+ }, {
+ .mask = _PAGE_USER,
+ .val = _PAGE_USER,
+ .set = "U",
+ .clear = ".",
+ }, {
+ .mask = _PAGE_EXEC,
+ .val = _PAGE_EXEC,
+ .set = "X",
+ .clear = ".",
+ }, {
+ .mask = _PAGE_WRITE,
+ .val = _PAGE_WRITE,
+ .set = "W",
+ .clear = ".",
+ }, {
+ .mask = _PAGE_READ,
+ .val = _PAGE_READ,
+ .set = "R",
+ .clear = ".",
+ }, {
+ .mask = _PAGE_PRESENT,
+ .val = _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++) {
+ const char *s;
+
+ if ((st->current_prot & pte_bits[i].mask) == pte_bits[i].val)
+ s = pte_bits[i].set;
+ else
+ s = pte_bits[i].clear;
+
+ if (s)
+ 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);
+}
+
+void 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);
+ else
+ pr_info("Checked W+X mappings: passed, no W+X pages found\n");
+}
+
+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);