mem_protect: Add mem_protect API

This patch adds the generic code that links the psci smc handler
with the platform function that implements the mem_protect and
mem_check_range functionalities. These functions are  optional
APIs added in PSCI v1.1 (ARM DEN022D).

Change-Id: I3bac1307a5ce2c7a196ace76db8317e8d8c8bb3f
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>

lib/psci/psci_mem_protect.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <limits.h>
+#include <utils.h>
+#include "psci_private.h"
+
+int psci_mem_protect(unsigned int enable)
+{
+	int val;
+
+	assert(psci_plat_pm_ops->read_mem_protect);
+	assert(psci_plat_pm_ops->write_mem_protect);
+
+	if (psci_plat_pm_ops->read_mem_protect(&val) < 0)
+		return PSCI_E_NOT_SUPPORTED;
+	if (psci_plat_pm_ops->write_mem_protect(enable) < 0)
+		return PSCI_E_NOT_SUPPORTED;
+
+	return val != 0;
+}
+
+int psci_mem_chk_range(uintptr_t base, u_register_t length)
+{
+	int ret;
+
+	assert(psci_plat_pm_ops->mem_protect_chk);
+
+	if (length == 0 || check_uptr_overflow(base, length-1))
+		return PSCI_E_DENIED;
+
+	ret = psci_plat_pm_ops->mem_protect_chk(base, length);
+	return (ret < 0) ? PSCI_E_DENIED : PSCI_E_SUCCESS;
+}