PSCI SMC handler improvements

The SMC handler for PSCI was not correctly handling calls from
secure states, or from AArch32.

This patch completes the handler implementation to correctly
detect secure callers and to clear the top bits in parameters from
AArch32 callers.

The patch also reorganises the switch statement to separate SMC64 and
SMC32 function IDs which allows the compiler to generate much smaller
code for the function.

Change-Id: I36b1ac81fb14253d257255d0477771d54fab0d11

services/std_svc/psci/psci_main.c

@@ -221,50 +221,68 @@ uint64_t psci_smc_handler(uint32_t smc_fid,
 			  void *handle,
 			  uint64_t flags)
 {
-	uint64_t rc;
-
-	switch (smc_fid) {
-	case PSCI_VERSION:
-		rc = psci_version();
-		break;
-
-	case PSCI_CPU_OFF:
-		rc = __psci_cpu_off();
-		break;
-
-	case PSCI_CPU_SUSPEND_AARCH64:
-	case PSCI_CPU_SUSPEND_AARCH32:
-		rc = __psci_cpu_suspend(x1, x2, x3);
-		break;
-
-	case PSCI_CPU_ON_AARCH64:
-	case PSCI_CPU_ON_AARCH32:
-		rc = psci_cpu_on(x1, x2, x3);
-		break;
-
-	case PSCI_AFFINITY_INFO_AARCH32:
-	case PSCI_AFFINITY_INFO_AARCH64:
-		rc = psci_affinity_info(x1, x2);
-		break;
-
-	case PSCI_MIG_AARCH32:
-	case PSCI_MIG_AARCH64:
-		rc = psci_migrate(x1);
-		break;
-
-	case PSCI_MIG_INFO_TYPE:
-		rc = psci_migrate_info_type();
-		break;
-
-	case PSCI_MIG_INFO_UP_CPU_AARCH32:
-	case PSCI_MIG_INFO_UP_CPU_AARCH64:
-		rc = psci_migrate_info_up_cpu();
-		break;
-
-	default:
-		rc = SMC_UNK;
-		WARN("Unimplemented PSCI Call: 0x%x \n", smc_fid);
+	if (is_caller_secure(flags))
+		SMC_RET1(handle, SMC_UNK);
+
+	if (((smc_fid >> FUNCID_CC_SHIFT) & FUNCID_CC_MASK) == SMC_32) {
+		/* 32-bit PSCI function, clear top parameter bits */
+
+		x1 = (uint32_t)x1;
+		x2 = (uint32_t)x2;
+		x3 = (uint32_t)x3;
+
+		switch (smc_fid) {
+		case PSCI_VERSION:
+			SMC_RET1(handle, psci_version());
+
+		case PSCI_CPU_OFF:
+			SMC_RET1(handle, __psci_cpu_off());
+
+		case PSCI_CPU_SUSPEND_AARCH32:
+			SMC_RET1(handle, __psci_cpu_suspend(x1, x2, x3));
+
+		case PSCI_CPU_ON_AARCH32:
+			SMC_RET1(handle, psci_cpu_on(x1, x2, x3));
+
+		case PSCI_AFFINITY_INFO_AARCH32:
+			SMC_RET1(handle, psci_affinity_info(x1, x2));
+
+		case PSCI_MIG_AARCH32:
+			SMC_RET1(handle, psci_migrate(x1));
+
+		case PSCI_MIG_INFO_TYPE:
+			SMC_RET1(handle, psci_migrate_info_type());
+
+		case PSCI_MIG_INFO_UP_CPU_AARCH32:
+			SMC_RET1(handle, psci_migrate_info_up_cpu());
+
+		default:
+			break;
+		}
+	} else {
+		/* 64-bit PSCI function */
+
+		switch (smc_fid) {
+		case PSCI_CPU_SUSPEND_AARCH64:
+			SMC_RET1(handle, __psci_cpu_suspend(x1, x2, x3));
+
+		case PSCI_CPU_ON_AARCH64:
+			SMC_RET1(handle, psci_cpu_on(x1, x2, x3));
+
+		case PSCI_AFFINITY_INFO_AARCH64:
+			SMC_RET1(handle, psci_affinity_info(x1, x2));
+
+		case PSCI_MIG_AARCH64:
+			SMC_RET1(handle, psci_migrate(x1));
+
+		case PSCI_MIG_INFO_UP_CPU_AARCH64:
+			SMC_RET1(handle, psci_migrate_info_up_cpu());
+
+		default:
+			break;
+		}
 	}
 
-	SMC_RET1(handle, rc);
+	WARN("Unimplemented PSCI Call: 0x%x \n", smc_fid);
+	SMC_RET1(handle, SMC_UNK);
 }