1 files changed, 170 insertions, 190 deletions

diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c
index c2ac9b8ae612..8f9ff7e7187d 100644
--- a/arch/s390/mm/dump_pagetables.c
+++ b/arch/s390/mm/dump_pagetables.c
@@ -1,9 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/set_memory.h>
+#include <linux/ptdump.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
-#include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/kasan.h>
+#include <asm/ptdump.h>
 #include <asm/kasan.h>
 #include <asm/sections.h>
 
@@ -15,264 +17,235 @@ struct addr_marker {
 };
 
 enum address_markers_idx {
-	IDENTITY_NR = 0,
+	IDENTITY_BEFORE_NR = 0,
+	IDENTITY_BEFORE_END_NR,
 	KERNEL_START_NR,
 	KERNEL_END_NR,
+	IDENTITY_AFTER_NR,
+	IDENTITY_AFTER_END_NR,
 #ifdef CONFIG_KASAN
 	KASAN_SHADOW_START_NR,
 	KASAN_SHADOW_END_NR,
 #endif
 	VMEMMAP_NR,
+	VMEMMAP_END_NR,
 	VMALLOC_NR,
+	VMALLOC_END_NR,
 	MODULES_NR,
+	MODULES_END_NR,
 };
 
 static struct addr_marker address_markers[] = {
-	[IDENTITY_NR]		= {0, "Identity Mapping"},
+	[IDENTITY_BEFORE_NR]	= {0, "Identity Mapping Start"},
+	[IDENTITY_BEFORE_END_NR] = {(unsigned long)_stext, "Identity Mapping End"},
 	[KERNEL_START_NR]	= {(unsigned long)_stext, "Kernel Image Start"},
 	[KERNEL_END_NR]		= {(unsigned long)_end, "Kernel Image End"},
+	[IDENTITY_AFTER_NR]	= {(unsigned long)_end, "Identity Mapping Start"},
+	[IDENTITY_AFTER_END_NR]	= {0, "Identity Mapping End"},
 #ifdef CONFIG_KASAN
 	[KASAN_SHADOW_START_NR]	= {KASAN_SHADOW_START, "Kasan Shadow Start"},
 	[KASAN_SHADOW_END_NR]	= {KASAN_SHADOW_END, "Kasan Shadow End"},
 #endif
-	[VMEMMAP_NR]		= {0, "vmemmap Area"},
-	[VMALLOC_NR]		= {0, "vmalloc Area"},
-	[MODULES_NR]		= {0, "Modules Area"},
+	[VMEMMAP_NR]		= {0, "vmemmap Area Start"},
+	[VMEMMAP_END_NR]	= {0, "vmemmap Area End"},
+	[VMALLOC_NR]		= {0, "vmalloc Area Start"},
+	[VMALLOC_END_NR]	= {0, "vmalloc Area End"},
+	[MODULES_NR]		= {0, "Modules Area Start"},
+	[MODULES_END_NR]	= {0, "Modules Area End"},
 	{ -1, NULL }
 };
 
 struct pg_state {
+	struct ptdump_state ptdump;
+	struct seq_file *seq;
 	int level;
 	unsigned int current_prot;
+	bool check_wx;
+	unsigned long wx_pages;
 	unsigned long start_address;
-	unsigned long current_address;
 	const struct addr_marker *marker;
 };
 
+#define pt_dump_seq_printf(m, fmt, args...)	\
+({						\
+	struct seq_file *__m = (m);		\
+						\
+	if (__m)				\
+		seq_printf(__m, fmt, ##args);	\
+})
+
+#define pt_dump_seq_puts(m, fmt)		\
+({						\
+	struct seq_file *__m = (m);		\
+						\
+	if (__m)				\
+		seq_printf(__m, fmt);		\
+})
+
 static void print_prot(struct seq_file *m, unsigned int pr, int level)
 {
 	static const char * const level_name[] =
 		{ "ASCE", "PGD", "PUD", "PMD", "PTE" };
 
-	seq_printf(m, "%s ", level_name[level]);
+	pt_dump_seq_printf(m, "%s ", level_name[level]);
 	if (pr & _PAGE_INVALID) {
-		seq_printf(m, "I\n");
+		pt_dump_seq_printf(m, "I\n");
 		return;
 	}
-	seq_puts(m, (pr & _PAGE_PROTECT) ? "RO " : "RW ");
-	seq_puts(m, (pr & _PAGE_NOEXEC) ? "NX\n" : "X\n");
+	pt_dump_seq_puts(m, (pr & _PAGE_PROTECT) ? "RO " : "RW ");
+	pt_dump_seq_puts(m, (pr & _PAGE_NOEXEC) ? "NX\n" : "X\n");
 }
 
-static void note_page(struct seq_file *m, struct pg_state *st,
-		     unsigned int new_prot, int level)
+static void note_prot_wx(struct pg_state *st, unsigned long addr)
+{
+#ifdef CONFIG_DEBUG_WX
+	if (!st->check_wx)
+		return;
+	if (st->current_prot & _PAGE_INVALID)
+		return;
+	if (st->current_prot & _PAGE_PROTECT)
+		return;
+	if (st->current_prot & _PAGE_NOEXEC)
+		return;
+	/* The first lowcore page is currently still W+X. */
+	if (addr == PAGE_SIZE)
+		return;
+	WARN_ONCE(1, "s390/mm: Found insecure W+X mapping at address %pS\n",
+		  (void *)st->start_address);
+	st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
+#endif /* CONFIG_DEBUG_WX */
+}
+
+static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, u64 val)
 {
-	static const char units[] = "KMGTPE";
 	int width = sizeof(unsigned long) * 2;
+	static const char units[] = "KMGTPE";
 	const char *unit = units;
-	unsigned int prot, cur;
 	unsigned long delta;
+	struct pg_state *st;
+	struct seq_file *m;
+	unsigned int prot;
 
-	/*
-	 * If we have a "break" in the series, we need to flush the state
-	 * that we have now. "break" is either changing perms, levels or
-	 * address space marker.
-	 */
-	prot = new_prot;
-	cur = st->current_prot;
-
-	if (!st->level) {
-		/* First entry */
-		st->current_prot = new_prot;
+	st = container_of(pt_st, struct pg_state, ptdump);
+	m = st->seq;
+	prot = val & (_PAGE_PROTECT | _PAGE_NOEXEC);
+	if (level == 4 && (val & _PAGE_INVALID))
+		prot = _PAGE_INVALID;
+	/* For pmd_none() & friends val gets passed as zero. */
+	if (level != 4 && !val)
+		prot = _PAGE_INVALID;
+	/* Final flush from generic code. */
+	if (level == -1)
+		addr = max_addr;
+	if (st->level == -1) {
+		pt_dump_seq_printf(m, "---[ %s ]---\n", st->marker->name);
+		st->start_address = addr;
+		st->current_prot = prot;
 		st->level = level;
-		st->marker = address_markers;
-		seq_printf(m, "---[ %s ]---\n", st->marker->name);
-	} else if (prot != cur || level != st->level ||
-		   st->current_address >= st->marker[1].start_address) {
-		/* Print the actual finished series */
-		seq_printf(m, "0x%0*lx-0x%0*lx ",
-			   width, st->start_address,
-			   width, st->current_address);
-		delta = (st->current_address - st->start_address) >> 10;
+	} else if (prot != st->current_prot || level != st->level ||
+		   addr >= st->marker[1].start_address) {
+		note_prot_wx(st, addr);
+		pt_dump_seq_printf(m, "0x%0*lx-0x%0*lx ",
+				   width, st->start_address,
+				   width, addr);
+		delta = (addr - st->start_address) >> 10;
 		while (!(delta & 0x3ff) && unit[1]) {
 			delta >>= 10;
 			unit++;
 		}
-		seq_printf(m, "%9lu%c ", delta, *unit);
+		pt_dump_seq_printf(m, "%9lu%c ", delta, *unit);
 		print_prot(m, st->current_prot, st->level);
-		while (st->current_address >= st->marker[1].start_address) {
+		while (addr >= st->marker[1].start_address) {
 			st->marker++;
-			seq_printf(m, "---[ %s ]---\n", st->marker->name);
+			pt_dump_seq_printf(m, "---[ %s ]---\n", st->marker->name);
 		}
-		st->start_address = st->current_address;
-		st->current_prot = new_prot;
+		st->start_address = addr;
+		st->current_prot = prot;
 		st->level = level;
 	}
 }
 
-#ifdef CONFIG_KASAN
-static void note_kasan_early_shadow_page(struct seq_file *m,
-						struct pg_state *st)
-{
-	unsigned int prot;
-
-	prot = pte_val(*kasan_early_shadow_pte) &
-		(_PAGE_PROTECT | _PAGE_INVALID | _PAGE_NOEXEC);
-	note_page(m, st, prot, 4);
-}
-#endif
-
-/*
- * The actual page table walker functions. In order to keep the
- * implementation of print_prot() short, we only check and pass
- * _PAGE_INVALID and _PAGE_PROTECT flags to note_page() if a region,
- * segment or page table entry is invalid or read-only.
- * After all it's just a hint that the current level being walked
- * contains an invalid or read-only entry.
- */
-static void walk_pte_level(struct seq_file *m, struct pg_state *st,
-			   pmd_t *pmd, unsigned long addr)
-{
-	unsigned int prot;
-	pte_t *pte;
-	int i;
-
-	for (i = 0; i < PTRS_PER_PTE && addr < max_addr; i++) {
-		st->current_address = addr;
-		pte = pte_offset_kernel(pmd, addr);
-		prot = pte_val(*pte) &
-			(_PAGE_PROTECT | _PAGE_INVALID | _PAGE_NOEXEC);
-		note_page(m, st, prot, 4);
-		addr += PAGE_SIZE;
-	}
-}
-
-static void walk_pmd_level(struct seq_file *m, struct pg_state *st,
-			   pud_t *pud, unsigned long addr)
-{
-	unsigned int prot;
-	pmd_t *pmd;
-	int i;
-
-#ifdef CONFIG_KASAN
-	if ((pud_val(*pud) & PAGE_MASK) == __pa(kasan_early_shadow_pmd)) {
-		note_kasan_early_shadow_page(m, st);
-		return;
-	}
-#endif
-
-	pmd = pmd_offset(pud, addr);
-	for (i = 0; i < PTRS_PER_PMD && addr < max_addr; i++, pmd++) {
-		st->current_address = addr;
-		if (!pmd_none(*pmd)) {
-			if (pmd_large(*pmd)) {
-				prot = pmd_val(*pmd) &
-					(_SEGMENT_ENTRY_PROTECT |
-					 _SEGMENT_ENTRY_NOEXEC);
-				note_page(m, st, prot, 3);
-			} else
-				walk_pte_level(m, st, pmd, addr);
-		} else
-			note_page(m, st, _PAGE_INVALID, 3);
-		addr += PMD_SIZE;
-	}
-}
-
-static void walk_pud_level(struct seq_file *m, struct pg_state *st,
-			   p4d_t *p4d, unsigned long addr)
+#ifdef CONFIG_DEBUG_WX
+void ptdump_check_wx(void)
 {
-	unsigned int prot;
-	pud_t *pud;
-	int i;
+	struct pg_state st = {
+		.ptdump = {
+			.note_page = note_page,
+			.range = (struct ptdump_range[]) {
+				{.start = 0, .end = max_addr},
+				{.start = 0, .end = 0},
+			}
+		},
+		.seq = NULL,
+		.level = -1,
+		.current_prot = 0,
+		.check_wx = true,
+		.wx_pages = 0,
+		.start_address = 0,
+		.marker = (struct addr_marker[]) {
+			{ .start_address =  0, .name = NULL},
+			{ .start_address = -1, .name = NULL},
+		},
+	};
 
-#ifdef CONFIG_KASAN
-	if ((p4d_val(*p4d) & PAGE_MASK) == __pa(kasan_early_shadow_pud)) {
-		note_kasan_early_shadow_page(m, st);
+	if (!MACHINE_HAS_NX)
 		return;
-	}
-#endif
-
-	pud = pud_offset(p4d, addr);
-	for (i = 0; i < PTRS_PER_PUD && addr < max_addr; i++, pud++) {
-		st->current_address = addr;
-		if (!pud_none(*pud))
-			if (pud_large(*pud)) {
-				prot = pud_val(*pud) &
-					(_REGION_ENTRY_PROTECT |
-					 _REGION_ENTRY_NOEXEC);
-				note_page(m, st, prot, 2);
-			} else
-				walk_pmd_level(m, st, pud, addr);
-		else
-			note_page(m, st, _PAGE_INVALID, 2);
-		addr += PUD_SIZE;
-	}
+	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 unexpected W+X pages found\n");
 }
+#endif /* CONFIG_DEBUG_WX */
 
-static void walk_p4d_level(struct seq_file *m, struct pg_state *st,
-			   pgd_t *pgd, unsigned long addr)
+#ifdef CONFIG_PTDUMP_DEBUGFS
+static int ptdump_show(struct seq_file *m, void *v)
 {
-	p4d_t *p4d;
-	int i;
-
-#ifdef CONFIG_KASAN
-	if ((pgd_val(*pgd) & PAGE_MASK) == __pa(kasan_early_shadow_p4d)) {
-		note_kasan_early_shadow_page(m, st);
-		return;
-	}
-#endif
+	struct pg_state st = {
+		.ptdump = {
+			.note_page = note_page,
+			.range = (struct ptdump_range[]) {
+				{.start = 0, .end = max_addr},
+				{.start = 0, .end = 0},
+			}
+		},
+		.seq = m,
+		.level = -1,
+		.current_prot = 0,
+		.check_wx = false,
+		.wx_pages = 0,
+		.start_address = 0,
+		.marker = address_markers,
+	};
 
-	p4d = p4d_offset(pgd, addr);
-	for (i = 0; i < PTRS_PER_P4D && addr < max_addr; i++, p4d++) {
-		st->current_address = addr;
-		if (!p4d_none(*p4d))
-			walk_pud_level(m, st, p4d, addr);
-		else
-			note_page(m, st, _PAGE_INVALID, 2);
-		addr += P4D_SIZE;
-	}
+	get_online_mems();
+	mutex_lock(&cpa_mutex);
+	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
+	mutex_unlock(&cpa_mutex);
+	put_online_mems();
+	return 0;
 }
+DEFINE_SHOW_ATTRIBUTE(ptdump);
+#endif /* CONFIG_PTDUMP_DEBUGFS */
 
-static void walk_pgd_level(struct seq_file *m)
+/*
+ * Heapsort from lib/sort.c is not a stable sorting algorithm, do a simple
+ * insertion sort to preserve the original order of markers with the same
+ * start address.
+ */
+static void sort_address_markers(void)
 {
-	unsigned long addr = 0;
-	struct pg_state st;
-	pgd_t *pgd;
-	int i;
+	struct addr_marker tmp;
+	int i, j;
 
-	memset(&st, 0, sizeof(st));
-	for (i = 0; i < PTRS_PER_PGD && addr < max_addr; i++) {
-		st.current_address = addr;
-		pgd = pgd_offset_k(addr);
-		if (!pgd_none(*pgd))
-			walk_p4d_level(m, &st, pgd, addr);
-		else
-			note_page(m, &st, _PAGE_INVALID, 1);
-		addr += PGDIR_SIZE;
-		cond_resched();
+	for (i = 1; i < ARRAY_SIZE(address_markers) - 1; i++) {
+		tmp = address_markers[i];
+		for (j = i - 1; j >= 0 && address_markers[j].start_address > tmp.start_address; j--)
+			address_markers[j + 1] = address_markers[j];
+		address_markers[j + 1] = tmp;
 	}
-	/* Flush out the last page */
-	st.current_address = max_addr;
-	note_page(m, &st, 0, 0);
 }
 
-static int ptdump_show(struct seq_file *m, void *v)
-{
-	walk_pgd_level(m);
-	return 0;
-}
-
-static int ptdump_open(struct inode *inode, struct file *filp)
-{
-	return single_open(filp, ptdump_show, NULL);
-}
-
-static const struct file_operations ptdump_fops = {
-	.open		= ptdump_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
-
 static int pt_dump_init(void)
 {
 	/*
@@ -282,10 +255,17 @@ static int pt_dump_init(void)
 	 */
 	max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2;
 	max_addr = 1UL << (max_addr * 11 + 31);
+	address_markers[IDENTITY_AFTER_END_NR].start_address = memory_end;
 	address_markers[MODULES_NR].start_address = MODULES_VADDR;
+	address_markers[MODULES_END_NR].start_address = MODULES_END;
 	address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap;
+	address_markers[VMEMMAP_END_NR].start_address = (unsigned long)vmemmap + vmemmap_size;
 	address_markers[VMALLOC_NR].start_address = VMALLOC_START;
+	address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
+	sort_address_markers();
+#ifdef CONFIG_PTDUMP_DEBUGFS
 	debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops);
+#endif /* CONFIG_PTDUMP_DEBUGFS */
 	return 0;
 }
 device_initcall(pt_dump_init);