[PATCH v2 2/3] riscv: ptdump: Use per-level attribute bits for parsing

[Dylan.Wu]

Instead of using the global pte_bits array in dump_prot(), use the
per-level bits and num from the associated pg_level entry passed via
ptdump_pg_state. This makes the attribute parsing logic fully driven by
the per-level configuration, which allows KVM (and other future users)
to plug in their own set of protection bits for their pagetable levels.

Rename the local pg_level[] array to kernel_pg_levels[] to avoid
shadowing the pg_level pointer in struct ptdump_pg_state.

Assisted-by: YuanSheng: deepseek-v4-pro
Co-developed-by: Quan Zhou <zhouquan at iscas.ac.cn>
Signed-off-by: Quan Zhou <zhouquan at iscas.ac.cn>
Signed-off-by: Dylan.Wu <fredwudi0305 at gmail.com>
---
 arch/riscv/include/asm/ptdump.h |  1 +
 arch/riscv/mm/ptdump.c          | 48 +++++++++++++++++++++------------
 2 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/arch/riscv/include/asm/ptdump.h b/arch/riscv/include/asm/ptdump.h
index eb9d11dab..14a262bd0 100644
--- a/arch/riscv/include/asm/ptdump.h
+++ b/arch/riscv/include/asm/ptdump.h
@@ -28,6 +28,7 @@ struct ptdump_pg_state {
 	struct seq_file *seq;
 	const struct addr_marker *marker;
 	unsigned long start_address;
+	const struct ptdump_pg_level *pg_level;
 	unsigned long start_pa;
 	unsigned long last_pa;
 	int level;
diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c
index 63655a9c8..06c0217f0 100644
--- a/arch/riscv/mm/ptdump.c
+++ b/arch/riscv/mm/ptdump.c
@@ -152,46 +152,58 @@ static const struct ptdump_prot_bits pte_bits[] = {
 	}
 };
 
-static struct ptdump_pg_level pg_level[] = {
+static struct ptdump_pg_level kernel_pg_levels[] = {
 	{ /* pgd */
+		.bits = pte_bits,
+		.num = ARRAY_SIZE(pte_bits),
 		.name = "PGD",
 	}, { /* p4d */
+		.bits = pte_bits,
+		.num = ARRAY_SIZE(pte_bits),
 		.name = (CONFIG_PGTABLE_LEVELS > 4) ? "P4D" : "PGD",
 	}, { /* pud */
+		.bits = pte_bits,
+		.num = ARRAY_SIZE(pte_bits),
 		.name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
 	}, { /* pmd */
+		.bits = pte_bits,
+		.num = ARRAY_SIZE(pte_bits),
 		.name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD",
 	}, { /* pte */
+		.bits = pte_bits,
+		.num = ARRAY_SIZE(pte_bits),
 		.name = "PTE",
 	},
 };
 
 static void dump_prot(struct ptdump_pg_state *st)
 {
+	const struct ptdump_pg_level *lvl = &st->pg_level[st->level];
+	const struct ptdump_prot_bits *bits = lvl->bits;
 	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(pte_bits); i++) {
+	for (i = 0; i < lvl->num; i++) {
 		char s[7];
 		unsigned long val;
 
-		val = st->current_prot & pte_bits[i].mask;
+		val = st->current_prot & bits[i].mask;
 		if (val) {
-			if (pte_bits[i].mask == _PAGE_SOFT)
-				snprintf(s, sizeof(s), pte_bits[i].set, val >> 8);
+			if (bits[i].mask == _PAGE_SOFT)
+				snprintf(s, sizeof(s), bits[i].set, val >> 8);
 #ifdef CONFIG_64BIT
-			else if (pte_bits[i].mask == _PAGE_MTMASK_SVPBMT) {
+			else if (bits[i].mask == _PAGE_MTMASK_SVPBMT) {
 				if (val == _PAGE_NOCACHE_SVPBMT)
-					snprintf(s, sizeof(s), pte_bits[i].set, "NC");
+					snprintf(s, sizeof(s), bits[i].set, "NC");
 				else if (val == _PAGE_IO_SVPBMT)
-					snprintf(s, sizeof(s), pte_bits[i].set, "IO");
+					snprintf(s, sizeof(s), bits[i].set, "IO");
 				else
-					snprintf(s, sizeof(s), pte_bits[i].set, "??");
+					snprintf(s, sizeof(s), bits[i].set, "??");
 			}
 #endif
 			else
-				strscpy(s, pte_bits[i].set);
+				strscpy(s, bits[i].set);
 		} else {
-			strscpy(s, pte_bits[i].clear);
+			strscpy(s, bits[i].clear);
 		}
 
 		pt_dump_seq_printf(st->seq, " %s", s);
@@ -221,7 +233,7 @@ static void dump_addr(struct ptdump_pg_state *st, unsigned long addr)
 	}
 
 	pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit,
-			   pg_level[st->level].name);
+			   kernel_pg_levels[st->level].name);
 }
 
 static void note_prot_wx(struct ptdump_pg_state *st, unsigned long addr)
@@ -247,7 +259,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr,
 	u64 prot = 0;
 
 	if (level >= 0)
-		prot = val & pg_level[level].mask;
+		prot = val & kernel_pg_levels[level].mask;
 
 	if (st->level == -1) {
 		st->level = level;
@@ -320,6 +332,7 @@ static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo)
 		.seq = s,
 		.marker = pinfo->markers,
 		.level = -1,
+		.pg_level = kernel_pg_levels,
 		.ptdump = {
 			.note_page_pte = note_page_pte,
 			.note_page_pmd = note_page_pmd,
@@ -346,6 +359,7 @@ bool ptdump_check_wx(void)
 			{-1, NULL},
 		},
 		.level = -1,
+		.pg_level = kernel_pg_levels,
 		.check_wx = true,
 		.ptdump = {
 			.note_page_pte = note_page_pte,
@@ -410,12 +424,12 @@ static int __init ptdump_init(void)
 
 	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";
+	kernel_pg_levels[1].name = pgtable_l5_enabled ? "P4D" : "PGD";
+	kernel_pg_levels[2].name = pgtable_l4_enabled ? "PUD" : "PGD";
 
-	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
+	for (i = 0; i < ARRAY_SIZE(kernel_pg_levels); i++)
 		for (j = 0; j < ARRAY_SIZE(pte_bits); j++)
-			pg_level[i].mask |= pte_bits[j].mask;
+			kernel_pg_levels[i].mask |= pte_bits[j].mask;
 
 	debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info,
 			    &ptdump_fops);
-- 
2.34.1