From 3524d0742e6dd4e8ed9e7a11d8268a9ea2f42c6a Mon Sep 17 00:00:00 2001
From: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
Date: Mon, 17 Jun 2024 15:28:33 -0500
Subject: [PATCH] feat(simd): add rules to rationalize simd ctxt mgmt

Illegal combinations of build flags associated with SIMD context
management are flagged by the build system.

Change-Id: I3192af3889e1e864c7875778616e167ba6894195
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
---
 Makefile                       | 59 +++++++++++++++++++++++++---------
 plat/arm/board/fvp/platform.mk |  4 +++
 2 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/Makefile b/Makefile
index c99b4bb83..f7737e350 100644
--- a/Makefile
+++ b/Makefile
@@ -975,25 +975,52 @@ ifeq (${ENABLE_SME_FOR_SWD},1)
 	endif
 endif #(ENABLE_SME_FOR_SWD)
 
+# Enabling SVE for SWD requires enabling SVE for NWD due to ENABLE_FEAT
+# mechanism.
 ifeq (${ENABLE_SVE_FOR_SWD},1)
-	ifeq (${ENABLE_SVE_FOR_NS},0)
-                $(error "ENABLE_SVE_FOR_SWD requires ENABLE_SVE_FOR_NS")
-	endif
-endif #(ENABLE_SVE_FOR_SWD)
+    ifeq (${ENABLE_SVE_FOR_NS},0)
+        $(error "ENABLE_SVE_FOR_SWD requires ENABLE_SVE_FOR_NS")
+    endif
+endif
 
-# SVE and SME cannot be used with CTX_INCLUDE_FPREGS since secure manager does
-# its own context management including FPU registers.
+# Enabling SVE for both the worlds typically requires the context
+# management of SVE registers. The only exception being SPMC at S-EL2.
+ifeq (${ENABLE_SVE_FOR_SWD}, 1)
+    ifneq (${ENABLE_SVE_FOR_NS}, 0)
+        ifeq (${CTX_INCLUDE_SVE_REGS}-$(SPMD_SPM_AT_SEL2),0-0)
+            $(warning "ENABLE_SVE_FOR_SWD and ENABLE_SVE_FOR_NS together require CTX_INCLUDE_SVE_REGS")
+        endif
+    endif
+endif
+
+# Enabling SVE in either world while enabling CTX_INCLUDE_FPREGS requires
+# CTX_INCLUDE_SVE_REGS to be enabled due to architectural dependency between FP
+# and SVE registers.
+ifeq (${CTX_INCLUDE_FPREGS}, 1)
+    ifneq (${ENABLE_SVE_FOR_NS},0)
+        ifeq (${CTX_INCLUDE_SVE_REGS},0)
+	    # Warning instead of error due to CI dependency on this
+            $(warning "CTX_INCLUDE_FPREGS and ENABLE_SVE_FOR_NS together require CTX_INCLUDE_SVE_REGS")
+            $(warning "Forced ENABLE_SVE_FOR_NS=0")
+	    override ENABLE_SVE_FOR_NS	:= 0
+        endif
+    endif
+endif #(CTX_INCLUDE_FPREGS)
+
+# SVE context management is only required if secure world has access to SVE/FP
+# functionality.
+ifeq (${CTX_INCLUDE_SVE_REGS},1)
+    ifeq (${ENABLE_SVE_FOR_SWD},0)
+        $(error "CTX_INCLUDE_SVE_REGS requires ENABLE_SVE_FOR_SWD to also be enabled")
+    endif
+endif
+
+# SME cannot be used with CTX_INCLUDE_FPREGS since SPM does its own context
+# management including FPU registers.
 ifeq (${CTX_INCLUDE_FPREGS},1)
-	ifneq (${ENABLE_SME_FOR_NS},0)
-                $(error "ENABLE_SME_FOR_NS cannot be used with CTX_INCLUDE_FPREGS")
-	endif
-
-	ifeq (${ENABLE_SVE_FOR_NS},1)
-		# Warning instead of error due to CI dependency on this
-                $(warning "ENABLE_SVE_FOR_NS cannot be used with CTX_INCLUDE_FPREGS")
-                $(warning "Forced ENABLE_SVE_FOR_NS=0")
-		override ENABLE_SVE_FOR_NS	:= 0
-	endif
+    ifneq (${ENABLE_SME_FOR_NS},0)
+        $(error "ENABLE_SME_FOR_NS cannot be used with CTX_INCLUDE_FPREGS")
+    endif
 endif #(CTX_INCLUDE_FPREGS)
 
 ifeq ($(DRTM_SUPPORT),1)
diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk
index cef7bdfcc..340eb3829 100644
--- a/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@ -47,6 +47,10 @@ ifeq (${SPM_MM}, 0)
 ifeq (${CTX_INCLUDE_FPREGS}, 0)
       ENABLE_SME_FOR_NS		:= 2
       ENABLE_SME2_FOR_NS	:= 2
+else
+      ENABLE_SVE_FOR_NS		:= 0
+      ENABLE_SME_FOR_NS		:= 0
+      ENABLE_SME2_FOR_NS	:= 0
 endif
 endif