Merge pull request #1109 from robertovargas-arm/mem_protect

Mem protect

plat/arm/common/arm_nor_psci_mem_protect.c

+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <debug.h>
+#include <mmio.h>
+#include <norflash.h>
+#include <plat_arm.h>
+#include <platform_def.h>
+#include <psci.h>
+#include <utils.h>
+
+mem_region_t arm_ram_ranges[] = {
+	{ARM_NS_DRAM1_BASE, ARM_NS_DRAM1_SIZE},
+#ifdef AARCH64
+	{ARM_DRAM2_BASE, ARM_DRAM2_SIZE},
+#endif
+};
+
+/*******************************************************************************
+ * Function that reads the content of the memory protect variable that
+ * enables clearing of non secure memory when system boots. This variable
+ * should be stored in a secure NVRAM.
+ ******************************************************************************/
+int arm_psci_read_mem_protect(int *enabled)
+{
+	int tmp;
+
+	tmp = *(int *) PLAT_ARM_MEM_PROT_ADDR;
+	*enabled = (tmp == 1);
+	return 0;
+}
+
+/*******************************************************************************
+ * Function that writes the content of the memory protect variable that
+ * enables overwritten of non secure memory when system boots.
+ ******************************************************************************/
+int arm_nor_psci_write_mem_protect(int val)
+{
+	int enable = (val != 0);
+
+	if (nor_unlock(PLAT_ARM_MEM_PROT_ADDR) != 0) {
+		ERROR("unlocking memory protect variable\n");
+		return -1;
+	}
+
+	if (enable) {
+		/*
+		 * If we want to write a value different than 0
+		 * then we have to erase the full block because
+		 * otherwise we cannot ensure that the value programmed
+		 * into the flash is going to be the same than the value
+		 * requested by the caller
+		 */
+		if (nor_erase(PLAT_ARM_MEM_PROT_ADDR) != 0) {
+			ERROR("erasing block containing memory protect variable\n");
+			return -1;
+		}
+	}
+
+	if (nor_word_program(PLAT_ARM_MEM_PROT_ADDR, enable) != 0) {
+		ERROR("programming memory protection variable\n");
+		return -1;
+	}
+	return 0;
+}
+
+/*******************************************************************************
+ * Function used for required psci operations performed when
+ * system boots
+ ******************************************************************************/
+void arm_nor_psci_do_mem_protect(void)
+{
+	int enable;
+
+	arm_psci_read_mem_protect(&enable);
+	if (!enable)
+		return;
+	INFO("PSCI: Overwritting non secure memory\n");
+	clear_mem_regions(arm_ram_ranges, ARRAY_SIZE(arm_ram_ranges));
+	arm_nor_psci_write_mem_protect(0);
+}
+
+/*******************************************************************************
+ * Function that checks if a region is protected by the memory protect
+ * mechanism
+ ******************************************************************************/
+int arm_psci_mem_protect_chk(uintptr_t base, u_register_t length)
+{
+	return mem_region_in_array_chk(arm_ram_ranges,
+				       ARRAY_SIZE(arm_ram_ranges),
+				       base, length);
+}

plat/arm/css/common/css_pm.c

@@ -290,5 +290,14 @@ plat_psci_ops_t plat_arm_psci_pm_ops = {
 	.validate_ns_entrypoint = arm_validate_ns_entrypoint,
 	.translate_power_state_by_mpidr = css_translate_power_state_by_mpidr,
 	.get_node_hw_state	= css_node_hw_state,
-	.get_sys_suspend_power_state = css_get_sys_suspend_power_state
+	.get_sys_suspend_power_state = css_get_sys_suspend_power_state,
+/*
+ * mem_protect is not supported in RESET_TO_BL31 and RESET_TO_SP_MIN,
+ * as that would require mapping in all of NS DRAM into BL31 or BL32.
+ */
+#if defined(PLAT_ARM_MEM_PROT_ADDR) && !RESET_TO_BL31 && !RESET_TO_SP_MIN
+	.mem_protect_chk	= arm_psci_mem_protect_chk,
+	.read_mem_protect	= arm_psci_read_mem_protect,
+	.write_mem_protect	= arm_nor_psci_write_mem_protect,
+#endif
 };