arm64: ptdump: Expose the attribute parsing functionality

Reuse the descriptor parsing functionality to keep the same output format
as the original ptdump code. In order for this to happen, move the state
tracking objects into a common header.

[maz: Fixed note_page() stub as suggested by Will]

Signed-off-by: Sebastian Ene <sebastianene@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240909124721.1672199-3-sebastianene@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Sebastian Ene

arch/arm64/include/asm/ptdump.h

@@ -5,6 +5,8 @@
 #ifndef __ASM_PTDUMP_H
 #define __ASM_PTDUMP_H
 
+#include <linux/ptdump.h>
+
 #ifdef CONFIG_PTDUMP_CORE
 
 #include <linux/mm_types.h>
@@ -21,14 +23,52 @@ struct ptdump_info {
 	unsigned long			base_addr;
 };
 
+struct ptdump_prot_bits {
+	u64		mask;
+	u64		val;
+	const char	*set;
+	const char	*clear;
+};
+
+struct ptdump_pg_level {
+	const struct ptdump_prot_bits *bits;
+	char name[4];
+	int num;
+	u64 mask;
+};
+
+/*
+ * 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 ptdump_pg_state {
+	struct ptdump_state ptdump;
+	struct seq_file *seq;
+	const struct addr_marker *marker;
+	const struct mm_struct *mm;
+	unsigned long start_address;
+	int level;
+	u64 current_prot;
+	bool check_wx;
+	unsigned long wx_pages;
+	unsigned long uxn_pages;
+};
+
 void ptdump_walk(struct seq_file *s, struct ptdump_info *info);
+void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
+	       u64 val);
 #ifdef CONFIG_PTDUMP_DEBUGFS
 #define EFI_RUNTIME_MAP_END	DEFAULT_MAP_WINDOW_64
 void __init ptdump_debugfs_register(struct ptdump_info *info, const char *name);
 #else
 static inline void ptdump_debugfs_register(struct ptdump_info *info,
 					   const char *name) { }
-#endif
+#endif /* CONFIG_PTDUMP_DEBUGFS */
+#else
+static inline void note_page(struct ptdump_state *pt_st, unsigned long addr,
+			     int level, u64 val) { }
 #endif /* CONFIG_PTDUMP_CORE */
 
 #endif /* __ASM_PTDUMP_H */

arch/arm64/mm/ptdump.c

@@ -38,33 +38,7 @@
 		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;
-	const struct mm_struct *mm;
-	unsigned long start_address;
-	int level;
-	u64 current_prot;
-	bool check_wx;
-	unsigned long wx_pages;
-	unsigned long uxn_pages;
-};
-
-struct prot_bits {
-	u64		mask;
-	u64		val;
-	const char	*set;
-	const char	*clear;
-};
-
-static const struct prot_bits pte_bits[] = {
+static const struct ptdump_prot_bits pte_bits[] = {
 	{
 		.mask	= PTE_VALID,
 		.val	= PTE_VALID,
@@ -143,14 +117,7 @@ static const struct prot_bits pte_bits[] = {
 	}
 };
 
-struct pg_level {
-	const struct prot_bits *bits;
-	char name[4];
-	int num;
-	u64 mask;
-};
-
-static struct pg_level pg_level[] __ro_after_init = {
+static struct ptdump_pg_level pg_level[] __ro_after_init = {
 	{ /* pgd */
 		.name	= "PGD",
 		.bits	= pte_bits,
@@ -174,7 +141,7 @@ static struct pg_level pg_level[] __ro_after_init = {
 	},
 };
 
-static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
+static void dump_prot(struct ptdump_pg_state *st, const struct ptdump_prot_bits *bits,
 			size_t num)
 {
 	unsigned i;
@@ -192,7 +159,7 @@ static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
 	}
 }
 
-static void note_prot_uxn(struct pg_state *st, unsigned long addr)
+static void note_prot_uxn(struct ptdump_pg_state *st, unsigned long addr)
 {
 	if (!st->check_wx)
 		return;
@@ -206,7 +173,7 @@ static void note_prot_uxn(struct pg_state *st, unsigned long addr)
 	st->uxn_pages += (addr - st->start_address) / PAGE_SIZE;
 }
 
-static void note_prot_wx(struct pg_state *st, unsigned long addr)
+static void note_prot_wx(struct ptdump_pg_state *st, unsigned long addr)
 {
 	if (!st->check_wx)
 		return;
@@ -221,10 +188,10 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr)
 	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)
+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);
+	struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
 	static const char units[] = "KMGTPE";
 	u64 prot = 0;
 
@@ -286,12 +253,12 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
 void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
 {
 	unsigned long end = ~0UL;
-	struct pg_state st;
+	struct ptdump_pg_state st;
 
 	if (info->base_addr < TASK_SIZE_64)
 		end = TASK_SIZE_64;
 
-	st = (struct pg_state){
+	st = (struct ptdump_pg_state){
 		.seq = s,
 		.marker = info->markers,
 		.mm = info->mm,
@@ -324,7 +291,7 @@ static struct ptdump_info kernel_ptdump_info __ro_after_init = {
 
 bool ptdump_check_wx(void)
 {
-	struct pg_state st = {
+	struct ptdump_pg_state st = {
 		.seq = NULL,
 		.marker = (struct addr_marker[]) {
 			{ 0, NULL},