doc: Recommend using C rather than assembly language
Add a section for that in the coding guidelines.
Change-Id: Ie6819c4df5889a861460eb96acf2bc9c0cfb494e
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/docs/process/coding-guidelines.rst b/docs/process/coding-guidelines.rst
index 9708604..a8a8454 100644
--- a/docs/process/coding-guidelines.rst
+++ b/docs/process/coding-guidelines.rst
@@ -441,6 +441,25 @@
These guidelines should be updated if additional types are needed.
+Favor C language over assembly language
+---------------------------------------
+
+Generally, prefer code written in C over assembly. Assembly code is less
+portable, harder to understand, maintain and audit security wise. Also, static
+analysis tools generally don't analyze assembly code.
+
+There are, however, legitimate uses of assembly language. These include:
+
+ - Early boot code executed before the C runtime environment is setup.
+
+ - Exception handling code.
+
+ - Low-level code where the exact sequence of instructions executed on the CPU
+ matters, such as CPU reset sequences.
+
+ - Low-level code where specific system-level instructions must be used, such
+ as cache maintenance operations.
+
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