Move FPEXC32_EL2 to FP Context

The FPEXC32_EL2 register controls SIMD and FP functionality when the
lower ELs are executing in AArch32 mode. It is architecturally mapped
to AArch32 system register FPEXC.

This patch removes FPEXC32_EL2 register from the System Register context
and adds it to the floating-point context. EL3 only saves / restores the
floating-point context if the build option CTX_INCLUDE_FPREGS is set to 1.

The rationale for this change is that if the Secure world is using FP
functionality and EL3 is not managing the FP context, then the Secure
world will save / restore the appropriate FP registers.

NOTE - this is a break in behaviour in the unlikely case that
CTX_INCLUDE_FPREGS is set to 0 and the platform contains an AArch32
Secure Payload that modifies FPEXC, but does not save and restore
this register

Change-Id: Iab80abcbfe302752d52b323b4abcc334b585c184
Signed-off-by: David Cunado <david.cunado@arm.com>
diff --git a/include/lib/el3_runtime/aarch64/context.h b/include/lib/el3_runtime/aarch64/context.h
index a89468d..cf06a64 100644
--- a/include/lib/el3_runtime/aarch64/context.h
+++ b/include/lib/el3_runtime/aarch64/context.h
@@ -100,8 +100,7 @@
 #define CTX_SPSR_FIQ		U(0xd8)
 #define CTX_DACR32_EL2		U(0xe0)
 #define CTX_IFSR32_EL2		U(0xe8)
-#define CTX_FP_FPEXC32_EL2	U(0xf0)
-#define CTX_TIMER_SYSREGS_OFF	U(0x100) /* Align to the next 16 byte boundary */
+#define CTX_TIMER_SYSREGS_OFF	U(0xf0) /* Align to the next 16 byte boundary */
 #else
 #define CTX_TIMER_SYSREGS_OFF	U(0xc0)  /* Align to the next 16 byte boundary */
 #endif /* __CTX_INCLUDE_AARCH32_REGS__ */
@@ -161,7 +160,12 @@
 #define CTX_FP_Q31		U(0x1f0)
 #define CTX_FP_FPSR		U(0x200)
 #define CTX_FP_FPCR		U(0x208)
-#define CTX_FPREGS_END		U(0x210)
+#if CTX_INCLUDE_AARCH32_REGS
+#define CTX_FP_FPEXC32_EL2	U(0x210)
+#define CTX_FPREGS_END		U(0x220) /* Align to the next 16 byte boundary */
+#else
+#define CTX_FPREGS_END		U(0x210) /* Align to the next 16 byte boundary */
+#endif
 #endif
 
 #ifndef __ASSEMBLY__