This version of the platform specification doesn't mandate M-mode
requirements. However, it should specify M-mode access protection
from lower privilege modes for platforms that do implement M-mode.
Otherwise, it is not very clear that such protection is required
to avoid lower privilege modes overwriting the memory where resident
firmware continues to run.

Signed-off-by: Atish Patra <atishp@...>
---
riscv-platform-spec.adoc | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/riscv-platform-spec.adoc b/riscv-platform-spec.adoc
index e20703299937..049d81c88c26 100644
--- a/riscv-platform-spec.adoc
+++ b/riscv-platform-spec.adoc
@@ -538,6 +538,18 @@ software components:
Rationale: The platform specification intends to avoid fragmentation and
promotes interoperability.

+=== Security
+** If M-mode is supported in the platform, all machine mode assets, such as
+code and data, shall be protected from all non-machine mode accesses from the
+harts in the system. Additionally, I/O agent access protection must be
+required within the system to protect machine mode assets. Therefore, the
+following requirements are mandatory for platforms with M-mode:
+
+*** Platform must provide a protection mechanism from non-machine mode hart
+transactions that precisely traps if violated.
+*** Platform must provide a protection mechanism from I/O agents manipulating
+or accessing machine mode assets.
+
// Server extension for OS-A Platform
=== Server Extension
The server extension specifies additional requirements for server class
@@ -927,6 +939,16 @@ configuration.
** It is clearly understood what aspects of the platform boot process are
protected by secure boot.

+** If M-mode is supported in the platform, all machine mode assets, such as
+code and data, shall be protected from all non-machine mode accesses from the
+harts in the system. Additionally, I/O agent access protection must be
+required within the system to protect machine mode assets. Therefore, the
+following requirements are mandatory for platforms with M-mode:
+
+*** Platform must provide a protection mechanism from non-machine mode hart
+transactions that precisely traps if violated.
+*** Platform must provide a protection mechanism from I/O agents manipulating
+or accessing machine mode assets.

==== RAS
All the below mentioned RAS features are required for the OS-A platform server
--
2.33.1