From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
C'est la vie, the spec folks reserve the ability to make incompatible
changes between major versions of an extension. Their idea of backwards
compatibility appears driven by the hardware perspective - it's
backwards compatible if a later version is a subset of the existing
extension. IOW, if you supported `x` in vN, you still support `x` in
vN+1.
However in software terms, code that was built for the vN's `x`
extension may not work with the new definition.
Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/riscv/cpus.yaml | 3 +++
1 file changed, 3 insertions(+)
diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml
index db5253a2a74a..405915b04d69 100644
--- a/Documentation/devicetree/bindings/riscv/cpus.yaml
+++ b/Documentation/devicetree/bindings/riscv/cpus.yaml
@@ -91,6 +91,9 @@ properties:
Notably, riscv,isa was defined prior to the creation of the
Zicsr and Zifencei extensions and thus "i" implies
"zicsr_zifencei".
+ For the sake of backwards compatibility, an unversioned
+ extension means that the hart/platform is capable of
+ supporting version 1.0.0 of the extension.
While the isa strings in ISA specification are case
insensitive, letters in the riscv,isa string must be all
--
2.39.2
