docs(spm): add threat model for el3 spmc
Threat model for EL3 SPMC.
The mitigations are based on the guidance
provided in FF-A v1.1 EAC0 spec.
Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
Change-Id: I7f4c9370b6eefe6d1a7d1afac27e8b3a7b476072
diff --git a/docs/resources/diagrams/plantuml/el3_spm_dfd.puml b/docs/resources/diagrams/plantuml/el3_spm_dfd.puml
new file mode 100644
index 0000000..c716180
--- /dev/null
+++ b/docs/resources/diagrams/plantuml/el3_spm_dfd.puml
@@ -0,0 +1,78 @@
+/'
+ ' Copyright (c) 2022, Arm Limited. All rights reserved.
+ '
+ ' SPDX-License-Identifier: BSD-3-Clause
+ '/
+
+/'
+TF-A EL3 SPMC Data Flow Diagram
+'/
+
+@startuml
+digraph tfa_el3_dfd {
+
+ # Allow arrows to end on cluster boundaries
+ compound=true
+ concentrate=false
+ newrank=true
+
+ # Default settings for edges and nodes
+ edge [minlen=2 color="#8c1b07"]
+ node [fillcolor="#ffb866" style=filled shape=box fixedsize=true width=1.6 height=0.7]
+
+ # Nodes outside of the trust boundary
+ nsec [label="NS Client"]
+ ddr [label="External memory (DDR)"]
+
+ {rank="same" smmu, spmd}
+ # Trust boundary cluster
+ subgraph cluster_trusted {
+ graph [style=dashed color="#f22430"]
+ concentrate=false
+
+ # HW IPs cluster
+ subgraph cluster_ip {
+ label ="Hardware IPs";
+ graph [style=filled color="#000000" fillcolor="#ffd29e"]
+
+ rank="same"
+ gic [label="GIC" width=1.2 height=0.5]
+ smmu [label="SMMU" width=1.2 height=0.5]
+ uart [label="UART" width=1.2 height=0.5]
+ pe [label="PE" width=1.2 height=0.5]
+ }
+
+ # TF-A cluster
+ subgraph cluster_tfa {
+ label ="EL3 monitor";
+ graph [style=filled color="#000000" fillcolor="#faf9cd"]
+ {rank="same" spmc, bl31}
+ {rank="same" spmd, lsp}
+ spmc [label="SPMC" fillcolor="#ddffb3"]
+ bl31 [label="BL31" fillcolor="#ddffb3"];
+ spmd [label="SPMD" fillcolor="#ddffb3"]
+ lsp[label="LSP1" fillcolor="#ddffb3"]
+ }
+ bl2 [label="BL2" width=1.2 height=0.5]
+ }
+
+ # Secure Partitions cluster
+ subgraph cluster_sp {
+ label ="Secure Partitions";
+ graph [style=filled color="#000000" fillcolor="#faf9cd"]
+
+ sp1 [label="SP1" fillcolor="#ddffb3"]
+ }
+
+ sp1 -> spmc [dir="both" label="DF1"]
+ lsp -> spmc [dir="both" label="DF4"]
+ spmc -> spmd [dir="both" label="DF2"]
+ spmd -> nsec [dir="both" label="DF3"]
+ spmc -> smmu [lhead=cluster_spmc label="DF5"]
+ bl2 -> spmc [lhead=cluster_spmc label="DF6"]
+ bl2 -> sp1 [lhead=cluster_spmc label="DF6"]
+ sp1 -> ddr [dir="both" label="DF7"]
+ spmc -> ddr [dir="both" label="DF7"]
+}
+
+@enduml