Signed-off-by: Bin Meng <bmeng.cn@...>
---

riscv-sbi.adoc | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/riscv-sbi.adoc b/riscv-sbi.adoc
index 11c30c3..8696f97 100644
--- a/riscv-sbi.adoc
+++ b/riscv-sbi.adoc
@@ -34,6 +34,7 @@ https://creativecommons.org/licenses/by/4.0/.
* Improved SBI introduction secion
* Improved documentation of SBI hart state managment extension
* Added suspend function to SBI hart state managment extension
+* Clarified that a SBI extension cannot be partially implemented

=== Version 0.2

@@ -51,6 +52,11 @@ abstraction for platform (or hypervisor) specific functionality. The design
of the SBI follows the general RISC-V philosophy of having a small core along
with a set of optional modular extensions.

+SBI extensions as whole are optional but if a SBI <abc> extension compliant
+with SBI v0.X spec is implemented then all functions of SBI <abc> extension
+as defined in SBI v0.X are assumed to be present. Basically, a SBI extension
+cannot be partially implemented.
+
The higher privilege software providing SBI interface to the supervisor-mode
software is referred to as a SBI implemenation or Supervisor Execution
Environment (SEE). A SBI implementation (or SEE) can be platform runtime
--
2.25.1