SPM: Register Secure Partition priority level with ehf module

Register a priority level, PLAT_SP_PRI, for secure partition with EL3
exception handling framework(ehf) module.

The secure partition manager(SPM) would raise the core's priority to
PLAT_SP_PRI before entering the secure partition, to protect the core
from getting interrupted while in secure partition.

Change-Id: I686897f052a4371e0efa9b929c07d3ad77249e95
Signed-off-by: Sughosh Ganu <sughosh.ganu@arm.com>

plat/arm/board/fvp/include/platform_def.h

@@ -268,4 +268,6 @@
 #define PLAT_ARM_SP_IMAGE_STACK_BASE	(ARM_SP_IMAGE_NS_BUF_BASE +	\
 					 ARM_SP_IMAGE_NS_BUF_SIZE)
 
+#define PLAT_SP_PRI			PLAT_RAS_PRI
+
 #endif /* PLATFORM_DEF_H */

plat/arm/common/aarch64/arm_ehf.c

@@ -23,6 +23,9 @@ ehf_pri_desc_t arm_exceptions[] = {
 	/* Normal priority SDEI */
 	EHF_PRI_DESC(ARM_PRI_BITS, PLAT_SDEI_NORMAL_PRI),
 #endif
+#if ENABLE_SPM
+	EHF_PRI_DESC(ARM_PRI_BITS, PLAT_SP_PRI),
+#endif
 };
 
 /* Plug in ARM exceptions to Exception Handling Framework. */

plat/arm/css/sgi/include/sgi_base_platform_def.h

@@ -142,6 +142,8 @@
 					SOC_CSS_DEVICE_SIZE,	\
 					MT_DEVICE | MT_RW | MT_SECURE | MT_USER)
 
+#define PLAT_SP_PRI				PLAT_RAS_PRI
+
 #if RAS_EXTENSION
 /* Allocate 128KB for CPER buffers */
 #define PLAT_SP_BUF_BASE			ULL(0x20000)