1 files changed, 456 insertions, 0 deletions

diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
new file mode 100644
index 000000000..084779c5c
--- /dev/null
+++ b/arch/arm/mm/dump.c
@@ -0,0 +1,456 @@
+/*
+ * Debug helper to dump the current kernel pagetables of the system
+ * so that we can see what the various memory ranges are set to.
+ *
+ * Derived from x86 implementation:
+ * (C) Copyright 2008 Intel Corporation
+ *
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/seq_file.h>
+
+#include <asm/domain.h>
+#include <asm/fixmap.h>
+#include <asm/memory.h>
+#include <asm/pgtable.h>
+#include <asm/ptdump.h>
+
+static struct addr_marker address_markers[] = {
+	{ MODULES_VADDR,	"Modules" },
+	{ PAGE_OFFSET,		"Kernel Mapping" },
+	{ 0,			"vmalloc() Area" },
+	{ VMALLOC_END,		"vmalloc() End" },
+	{ FIXADDR_START,	"Fixmap Area" },
+	{ VECTORS_BASE,	"Vectors" },
+	{ VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
+	{ -1,			NULL },
+};
+
+#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);	\
+})
+
+struct pg_state {
+	struct seq_file *seq;
+	const struct addr_marker *marker;
+	unsigned long start_address;
+	unsigned level;
+	u64 current_prot;
+	bool check_wx;
+	unsigned long wx_pages;
+	const char *current_domain;
+};
+
+struct prot_bits {
+	u64		mask;
+	u64		val;
+	const char	*set;
+	const char	*clear;
+	bool		ro_bit;
+	bool		nx_bit;
+};
+
+static const struct prot_bits pte_bits[] = {
+	{
+		.mask	= L_PTE_USER,
+		.val	= L_PTE_USER,
+		.set	= "USR",
+		.clear	= "   ",
+	}, {
+		.mask	= L_PTE_RDONLY,
+		.val	= L_PTE_RDONLY,
+		.set	= "ro",
+		.clear	= "RW",
+		.ro_bit	= true,
+	}, {
+		.mask	= L_PTE_XN,
+		.val	= L_PTE_XN,
+		.set	= "NX",
+		.clear	= "x ",
+		.nx_bit	= true,
+	}, {
+		.mask	= L_PTE_SHARED,
+		.val	= L_PTE_SHARED,
+		.set	= "SHD",
+		.clear	= "   ",
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_UNCACHED,
+		.set	= "SO/UNCACHED",
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_BUFFERABLE,
+		.set	= "MEM/BUFFERABLE/WC",
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_WRITETHROUGH,
+		.set	= "MEM/CACHED/WT",
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_WRITEBACK,
+		.set	= "MEM/CACHED/WBRA",
+#ifndef CONFIG_ARM_LPAE
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_MINICACHE,
+		.set	= "MEM/MINICACHE",
+#endif
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_WRITEALLOC,
+		.set	= "MEM/CACHED/WBWA",
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_DEV_SHARED,
+		.set	= "DEV/SHARED",
+#ifndef CONFIG_ARM_LPAE
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_DEV_NONSHARED,
+		.set	= "DEV/NONSHARED",
+#endif
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_DEV_WC,
+		.set	= "DEV/WC",
+	}, {
+		.mask	= L_PTE_MT_MASK,
+		.val	= L_PTE_MT_DEV_CACHED,
+		.set	= "DEV/CACHED",
+	},
+};
+
+static const struct prot_bits section_bits[] = {
+#ifdef CONFIG_ARM_LPAE
+	{
+		.mask	= PMD_SECT_USER,
+		.val	= PMD_SECT_USER,
+		.set	= "USR",
+	}, {
+		.mask	= L_PMD_SECT_RDONLY | PMD_SECT_AP2,
+		.val	= L_PMD_SECT_RDONLY | PMD_SECT_AP2,
+		.set	= "ro",
+		.clear	= "RW",
+		.ro_bit	= true,
+#elif __LINUX_ARM_ARCH__ >= 6
+	{
+		.mask	= PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val	= PMD_SECT_APX | PMD_SECT_AP_WRITE,
+		.set	= "    ro",
+		.ro_bit	= true,
+	}, {
+		.mask	= PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val	= PMD_SECT_AP_WRITE,
+		.set	= "    RW",
+	}, {
+		.mask	= PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val	= PMD_SECT_AP_READ,
+		.set	= "USR ro",
+	}, {
+		.mask	= PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val	= PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.set	= "USR RW",
+#else /* ARMv4/ARMv5  */
+	/* These are approximate */
+	{
+		.mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val    = 0,
+		.set    = "    ro",
+		.ro_bit	= true,
+	}, {
+		.mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val    = PMD_SECT_AP_WRITE,
+		.set    = "    RW",
+	}, {
+		.mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val    = PMD_SECT_AP_READ,
+		.set    = "USR ro",
+	}, {
+		.mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.val    = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
+		.set    = "USR RW",
+#endif
+	}, {
+		.mask	= PMD_SECT_XN,
+		.val	= PMD_SECT_XN,
+		.set	= "NX",
+		.clear	= "x ",
+		.nx_bit	= true,
+	}, {
+		.mask	= PMD_SECT_S,
+		.val	= PMD_SECT_S,
+		.set	= "SHD",
+		.clear	= "   ",
+	},
+};
+
+struct pg_level {
+	const struct prot_bits *bits;
+	size_t num;
+	u64 mask;
+	const struct prot_bits *ro_bit;
+	const struct prot_bits *nx_bit;
+};
+
+static struct pg_level pg_level[] = {
+	{
+	}, { /* pgd */
+	}, { /* pud */
+	}, { /* pmd */
+		.bits	= section_bits,
+		.num	= ARRAY_SIZE(section_bits),
+	}, { /* pte */
+		.bits	= pte_bits,
+		.num	= ARRAY_SIZE(pte_bits),
+	},
+};
+
+static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t num)
+{
+	unsigned i;
+
+	for (i = 0; i < num; i++, bits++) {
+		const char *s;
+
+		if ((st->current_prot & bits->mask) == bits->val)
+			s = bits->set;
+		else
+			s = bits->clear;
+
+		if (s)
+			pt_dump_seq_printf(st->seq, " %s", s);
+	}
+}
+
+static void note_prot_wx(struct pg_state *st, unsigned long addr)
+{
+	if (!st->check_wx)
+		return;
+	if ((st->current_prot & pg_level[st->level].ro_bit->mask) ==
+				pg_level[st->level].ro_bit->val)
+		return;
+	if ((st->current_prot & pg_level[st->level].nx_bit->mask) ==
+				pg_level[st->level].nx_bit->val)
+		return;
+
+	WARN_ONCE(1, "arm/mm: Found insecure W+X mapping at address %pS\n",
+			(void *)st->start_address);
+
+	st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
+}
+
+static void note_page(struct pg_state *st, unsigned long addr,
+		      unsigned int level, u64 val, const char *domain)
+{
+	static const char units[] = "KMGTPE";
+	u64 prot = val & pg_level[level].mask;
+
+	if (!st->level) {
+		st->level = level;
+		st->current_prot = prot;
+		st->current_domain = domain;
+		pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+	} else if (prot != st->current_prot || level != st->level ||
+		   domain != st->current_domain ||
+		   addr >= st->marker[1].start_address) {
+		const char *unit = units;
+		unsigned long delta;
+
+		if (st->current_prot) {
+			note_prot_wx(st, addr);
+			pt_dump_seq_printf(st->seq, "0x%08lx-0x%08lx   ",
+				   st->start_address, addr);
+
+			delta = (addr - st->start_address) >> 10;
+			while (!(delta & 1023) && unit[1]) {
+				delta >>= 10;
+				unit++;
+			}
+			pt_dump_seq_printf(st->seq, "%9lu%c", delta, *unit);
+			if (st->current_domain)
+				pt_dump_seq_printf(st->seq, " %s",
+							st->current_domain);
+			if (pg_level[st->level].bits)
+				dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num);
+			pt_dump_seq_printf(st->seq, "\n");
+		}
+
+		if (addr >= st->marker[1].start_address) {
+			st->marker++;
+			pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
+							st->marker->name);
+		}
+		st->start_address = addr;
+		st->current_prot = prot;
+		st->current_domain = domain;
+		st->level = level;
+	}
+}
+
+static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start,
+		     const char *domain)
+{
+	pte_t *pte = pte_offset_kernel(pmd, 0);
+	unsigned long addr;
+	unsigned i;
+
+	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
+		addr = start + i * PAGE_SIZE;
+		note_page(st, addr, 4, pte_val(*pte), domain);
+	}
+}
+
+static const char *get_domain_name(pmd_t *pmd)
+{
+#ifndef CONFIG_ARM_LPAE
+	switch (pmd_val(*pmd) & PMD_DOMAIN_MASK) {
+	case PMD_DOMAIN(DOMAIN_KERNEL):
+		return "KERNEL ";
+	case PMD_DOMAIN(DOMAIN_USER):
+		return "USER   ";
+	case PMD_DOMAIN(DOMAIN_IO):
+		return "IO     ";
+	case PMD_DOMAIN(DOMAIN_VECTORS):
+		return "VECTORS";
+	default:
+		return "unknown";
+	}
+#endif
+	return NULL;
+}
+
+static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
+{
+	pmd_t *pmd = pmd_offset(pud, 0);
+	unsigned long addr;
+	unsigned i;
+	const char *domain;
+
+	for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
+		addr = start + i * PMD_SIZE;
+		domain = get_domain_name(pmd);
+		if (pmd_none(*pmd) || pmd_large(*pmd) || !pmd_present(*pmd))
+			note_page(st, addr, 3, pmd_val(*pmd), domain);
+		else
+			walk_pte(st, pmd, addr, domain);
+
+		if (SECTION_SIZE < PMD_SIZE && pmd_large(pmd[1])) {
+			addr += SECTION_SIZE;
+			pmd++;
+			domain = get_domain_name(pmd);
+			note_page(st, addr, 3, pmd_val(*pmd), domain);
+		}
+	}
+}
+
+static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
+{
+	pud_t *pud = pud_offset(pgd, 0);
+	unsigned long addr;
+	unsigned i;
+
+	for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
+		addr = start + i * PUD_SIZE;
+		if (!pud_none(*pud)) {
+			walk_pmd(st, pud, addr);
+		} else {
+			note_page(st, addr, 2, pud_val(*pud), NULL);
+		}
+	}
+}
+
+static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
+			unsigned long start)
+{
+	pgd_t *pgd = pgd_offset(mm, 0UL);
+	unsigned i;
+	unsigned long addr;
+
+	for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
+		addr = start + i * PGDIR_SIZE;
+		if (!pgd_none(*pgd)) {
+			walk_pud(st, pgd, addr);
+		} else {
+			note_page(st, addr, 1, pgd_val(*pgd), NULL);
+		}
+	}
+}
+
+void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info)
+{
+	struct pg_state st = {
+		.seq = m,
+		.marker = info->markers,
+		.check_wx = false,
+	};
+
+	walk_pgd(&st, info->mm, info->base_addr);
+	note_page(&st, 0, 0, 0, NULL);
+}
+
+static void ptdump_initialize(void)
+{
+	unsigned i, j;
+
+	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
+		if (pg_level[i].bits)
+			for (j = 0; j < pg_level[i].num; j++) {
+				pg_level[i].mask |= pg_level[i].bits[j].mask;
+				if (pg_level[i].bits[j].ro_bit)
+					pg_level[i].ro_bit = &pg_level[i].bits[j];
+				if (pg_level[i].bits[j].nx_bit)
+					pg_level[i].nx_bit = &pg_level[i].bits[j];
+			}
+
+	address_markers[2].start_address = VMALLOC_START;
+}
+
+static struct ptdump_info kernel_ptdump_info = {
+	.mm = &init_mm,
+	.markers = address_markers,
+	.base_addr = 0,
+};
+
+void ptdump_check_wx(void)
+{
+	struct pg_state st = {
+		.seq = NULL,
+		.marker = (struct addr_marker[]) {
+			{ 0, NULL},
+			{ -1, NULL},
+		},
+		.check_wx = true,
+	};
+
+	walk_pgd(&st, &init_mm, 0);
+	note_page(&st, 0, 0, 0, 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_init(void)
+{
+	ptdump_initialize();
+	return ptdump_debugfs_register(&kernel_ptdump_info,
+					"kernel_page_tables");
+}
+__initcall(ptdump_init);