linux-kernel - [PATCH v2 10/18] riscv: ptdump: Only show N and MT bits when enabled in the kernel

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Message-ID: <20251009015839.3460231-11-samuel.holland@sifive.com>
Date: Wed,  8 Oct 2025 18:57:46 -0700
From: Samuel Holland <samuel.holland@...ive.com>
To: Palmer Dabbelt <palmer@...belt.com>,
	Paul Walmsley <pjw@...nel.org>,
	linux-riscv@...ts.infradead.org
Cc: devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	Conor Dooley <conor@...nel.org>,
	Alexandre Ghiti <alex@...ti.fr>,
	Emil Renner Berthing <kernel@...il.dk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Samuel Holland <samuel.holland@...ive.com>,
	Alexandre Ghiti <alexghiti@...osinc.com>
Subject: [PATCH v2 10/18] 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 3b51690cc8760..6608162459ae0 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