[PATCH v3 07/15] dt-bindings: riscv: Add Zic64b extension description

Guodong Xu docular.xu at gmail.com
Wed Jun 3 04:12:02 PDT 2026


Zic64b mandates that cache blocks are 64 bytes in size and naturally
aligned in the address space.  It is a mandatory extension of both the
RVA22 (U64/S64) and RVA23 (U64/S64) profiles, ratified with RISC-V
Profiles Version 1.0.

Document it so it can be described in the riscv,isa-extensions property,
alongside the related Zicbom/Zicbop/Zicboz cache-block extensions.  As
Zic64b is the architectural guarantee that the cache block size is 64
bytes, also require a hart that advertises it to report cbom/cbop/cboz
block sizes of 64, so dtbs_check rejects an inconsistent description.

Signed-off-by: Guodong Xu <docular.xu at gmail.com>
---
v3: New patch.
---
 .../devicetree/bindings/riscv/extensions.yaml        | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index 2b0a8a93bb214..ec1c9473d4256 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -590,6 +590,12 @@ properties:
             in version 1.0 of RISC-V Cryptography Extensions Volume I
             specification.
 
+        - const: zic64b
+          description:
+            The standard Zic64b extension for 64-byte naturally aligned cache
+            blocks, as ratified in RISC-V Profiles Version 1.0, with commit
+            b1d806605f87 ("Updated to ratified state.")
+
         - const: zicbom
           description:
             The standard Zicbom extension for base cache management operations as
@@ -1142,6 +1148,20 @@ allOf:
           not:
             contains:
               const: zilsd
+  # Zic64b mandates 64-byte naturally aligned cache blocks
+  - if:
+      properties:
+        riscv,isa-extensions:
+          contains:
+            const: zic64b
+    then:
+      properties:
+        riscv,cbom-block-size:
+          const: 64
+        riscv,cbop-block-size:
+          const: 64
+        riscv,cboz-block-size:
+          const: 64
 
 additionalProperties: true
 ...

-- 
2.43.0




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