linux-kernel - [PATCH v3 13/22] riscv: ptdump: Only show N and MT bits when enabled in the kernel

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Message-ID: <20251113014656.2605447-14-samuel.holland@sifive.com>
Date: Wed, 12 Nov 2025 17:45:26 -0800
From: Samuel Holland <samuel.holland@...ive.com>
To: Palmer Dabbelt <palmer@...belt.com>,
	Paul Walmsley <pjw@...nel.org>,
	linux-riscv@...ts.infradead.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Hildenbrand <david@...hat.com>,
	linux-mm@...ck.org
Cc: devicetree@...r.kernel.org,
	Suren Baghdasaryan <surenb@...gle.com>,
	linux-kernel@...r.kernel.org,
	Mike Rapoport <rppt@...nel.org>,
	Michal Hocko <mhocko@...e.com>,
	Conor Dooley <conor@...nel.org>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Alexandre Ghiti <alex@...ti.fr>,
	Emil Renner Berthing <kernel@...il.dk>,
	Rob Herring <robh+dt@...nel.org>,
	Vlastimil Babka <vbabka@...e.cz>,
	"Liam R . Howlett" <Liam.Howlett@...cle.com>,
	Samuel Holland <samuel.holland@...ive.com>,
	Alexandre Ghiti <alexghiti@...osinc.com>
Subject: [PATCH v3 13/22] riscv: ptdump: Only show N and MT bits when enabled in the kernel

When the Svnapot or Svpbmt extension is not implemented, the
corresponding page table bits are reserved, and must be zero. There is
no need to show them in the ptdump output.

When the Kconfig option for an extension is disabled, we assume it is
not implemented. In that case, the kernel may provide a fallback
definition for the fields, like how _PAGE_MTMASK is defined on riscv32.
Using those fallback definitions in ptdump would produce incorrect
results. To avoid this, hide the fields from the ptdump output.

Reviewed-by: Alexandre Ghiti <alexghiti@...osinc.com>
Signed-off-by: Samuel Holland <samuel.holland@...ive.com>
---

(no changes since v1)

 arch/riscv/mm/ptdump.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c
index 34299c2b231f..0dd6ee282953 100644
--- a/arch/riscv/mm/ptdump.c
+++ b/arch/riscv/mm/ptdump.c
@@ -134,11 +134,13 @@ struct prot_bits {
 
 static const struct prot_bits pte_bits[] = {
 	{
-#ifdef CONFIG_64BIT
+#ifdef CONFIG_RISCV_ISA_SVNAPOT
 		.mask = _PAGE_NAPOT,
 		.set = "N",
 		.clear = ".",
 	}, {
+#endif
+#ifdef CONFIG_RISCV_ISA_SVPBMT
 		.mask = _PAGE_MTMASK_SVPBMT,
 		.set = "MT(%s)",
 		.clear = "  ..  ",
@@ -214,7 +216,7 @@ static void dump_prot(struct pg_state *st)
 		if (val) {
 			if (pte_bits[i].mask == _PAGE_SOFT)
 				sprintf(s, pte_bits[i].set, val >> 8);
-#ifdef CONFIG_64BIT
+#ifdef CONFIG_RISCV_ISA_SVPBMT
 			else if (pte_bits[i].mask == _PAGE_MTMASK_SVPBMT) {
 				if (val == _PAGE_NOCACHE_SVPBMT)
 					sprintf(s, pte_bits[i].set, "NC");
-- 
2.47.2