[PATCH 3/3] RISC-V: Include documentation for hwprobe vendor extensions

[Charlie Jenkins]

Document available vendor extensions.

Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
---
 Documentation/riscv/hwprobe.rst | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/riscv/hwprobe.rst b/Documentation/riscv/hwprobe.rst
index 19165ebd82ba..167fd3e25632 100644
--- a/Documentation/riscv/hwprobe.rst
+++ b/Documentation/riscv/hwprobe.rst
@@ -97,3 +97,20 @@ The following keys are defined:
 
   * :c:macro:`RISCV_HWPROBE_MISALIGNED_UNSUPPORTED`: Misaligned accesses are
     not supported at all and will generate a misaligned address fault.
+
+RISC-V Hardware Probing Interface Vendor Extensions
+---------------------------------------------------
+
+All vendor extensions live at and beyond
+:c:macro:`RISCV_HWPROBE_VENDOR_EXTENSION_SPACE`. Each vendor can specify vendor
+extensions at any value above or equal to
+:c:macro:`RISCV_HWPROBE_VENDOR_EXTENSION_SPACE` without worrying about
+conflicting with values from other vendors. Only extensions from the vendor of
+the cpus passed into riscv_hwprobe will be matched.
+
+T-HEAD
+~~~~~~
+
+* :c:macro:`THEAD_ISA_EXT0`: Contains all of the EXT0 extensions
+
+  * :c:macro:`THEAD_ISA_EXT0_V0_7_1`: Vector extension V0.7.1 is supported

-- 
2.41.0