Re: [PATCH v5 2/4] dt-bindings: riscv: Add Svade and Svadu Entries

From: Alexandre Ghiti
Date: Fri Jun 21 2024 - 04:07:30 EST


On 05/06/2024 14:15, Yong-Xuan Wang wrote:
Add entries for the Svade and Svadu extensions to the riscv,isa-extensions
property.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@xxxxxxxxxx>
---
.../devicetree/bindings/riscv/extensions.yaml | 30 +++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index 468c646247aa..1e30988826b9 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -153,6 +153,36 @@ properties:
ratified at commit 3f9ed34 ("Add ability to manually trigger
workflow. (#2)") of riscv-time-compare.
+ - const: svade
+ description: |
+ The standard Svade supervisor-level extension for raising page-fault
+ exceptions when PTE A/D bits need be set


Maybe something like:

"The standard Svade supervisor-level extension for SW-managed PTE A/D bit updates as ratified..."

would be better, WDYT?


as ratified in the 20240213
+ version of the privileged ISA specification.
+
+ Both Svade and Svadu extensions control the hardware behavior when
+ the PTE A/D bits need to be set. The default behavior for the four
+ possible combinations of these extensions in the device tree are:
+ 1. Neither svade nor svadu in DT: default to svade.
+ 2. Only svade in DT: use svade.
+ 3. Only svadu in DT: use svadu.
+ 4. Both svade and svadu in DT: default to svade (Linux can switch to
+ svadu once the SBI FWFT extension is available).
+
+ - const: svadu
+ description: |
+ The standard Svadu supervisor-level extension for hardware updating
+ of PTE A/D bits as ratified at commit c1abccf ("Merge pull request
+ #25 from ved-rivos/ratified") of riscv-svadu.
+
+ Both Svade and Svadu extensions control the hardware behavior when
+ the PTE A/D bits need to be set. The default behavior for the four
+ possible combinations of these extensions in the device tree are:
+ 1. Neither svade nor svadu in DT: default to svade.
+ 2. Only svade in DT: use svade.
+ 3. Only svadu in DT: use svadu.
+ 4. Both svade and svadu in DT: default to svade (Linux can switch to
+ svadu once the SBI FWFT extension is available).


I would not duplicate this text, but rather say something like "Please refer to Svade dt-binding description for more details.".


+
- const: svinval
description:
The standard Svinval supervisor-level extension for fine-grained