riscv-sbi.adoc: Clarify that an SBI extension shall not be partially …

…implemented Mention that an SBI extension shall not be partially implemented. Signed-off-by: Bin Meng <[email protected]>
riscv-non-isa · Jun 8, 2021 · 248971a · 248971a
1 parent c52ab59
commit 248971a
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/riscv-sbi.adoc b/riscv-sbi.adoc
@@ -35,6 +35,7 @@ https://creativecommons.org/licenses/by/4.0/.
 * Improved documentation of SBI hart state managment extension
 * Added suspend function to SBI hart state managment extension
 * Added performance monitoring unit extension
+* Clarified that an SBI extension shall not be partially implemented
 
 === Version 0.2
 
@@ -52,6 +53,11 @@ 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 they shall not be partially
+implemented. If sbi_probe_extension() signals that an extension is available,
+all functions conforming to the SBI version reported by sbi_get_spec_version()
+must be implemented in total.
+
 The higher privilege software providing SBI interface to the supervisor-mode
 software is referred to as an SBI implemenation or Supervisor Execution
 Environment (SEE). An SBI implementation (or SEE) can be platform runtime