refactor(spmd): call cm_get_context once

As observed by tracing instruction execution the SMC_RET18
macro in spmd_smc_switch_state calls cm_get_context, however the
compiler expands it to multiple individual non-inlined calls to
this same function. Store the result of cm_get_context into a local
variable and use it in the macro such that this function is only called
once.

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: Ib4fa63aced2f07c67c057f54fef3780c85e91df7

services/std_svc/spmd/spmd_main.c

@@ -662,6 +662,7 @@ uint64_t spmd_smc_switch_state(uint32_t smc_fid,
 {
 	unsigned int secure_state_in = (secure_origin) ? SECURE : NON_SECURE;
 	unsigned int secure_state_out = (!secure_origin) ? SECURE : NON_SECURE;
+	void *ctx_out;
 
 #if SPMD_SPM_AT_SEL2
 	if ((secure_state_out == SECURE) && (is_sve_hint_set(flags) == true)) {
@@ -688,6 +689,7 @@ uint64_t spmd_smc_switch_state(uint32_t smc_fid,
 #endif
 	cm_set_next_eret_context(secure_state_out);
 
+	ctx_out = cm_get_context(secure_state_out);
 #if SPMD_SPM_AT_SEL2
 	/*
 	 * If SPMC is at SEL2, save additional registers x8-x17, which may
@@ -700,7 +702,7 @@ uint64_t spmd_smc_switch_state(uint32_t smc_fid,
 	 * preserved, so the SPMD passes through these registers and expects the
 	 * SPMC to save and restore (potentially also modify) them.
 	 */
-	SMC_RET18(cm_get_context(secure_state_out), smc_fid, x1, x2, x3, x4,
+	SMC_RET18(ctx_out, smc_fid, x1, x2, x3, x4,
 			SMC_GET_GP(handle, CTX_GPREG_X5),
 			SMC_GET_GP(handle, CTX_GPREG_X6),
 			SMC_GET_GP(handle, CTX_GPREG_X7),
@@ -717,7 +719,7 @@ uint64_t spmd_smc_switch_state(uint32_t smc_fid,
 			);
 
 #else
-	SMC_RET8(cm_get_context(secure_state_out), smc_fid, x1, x2, x3, x4,
+	SMC_RET8(ctx_out, smc_fid, x1, x2, x3, x4,
 			SMC_GET_GP(handle, CTX_GPREG_X5),
 			SMC_GET_GP(handle, CTX_GPREG_X6),
 			SMC_GET_GP(handle, CTX_GPREG_X7));