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>

include/lib/psci/psci.h

@@ -65,6 +65,9 @@
 #define PSCI_STAT_RESIDENCY_AARCH64	U(0xc4000010)
 #define PSCI_STAT_COUNT_AARCH32		U(0x84000011)
 #define PSCI_STAT_COUNT_AARCH64		U(0xc4000011)
+#define PSCI_MEM_PROTECT		U(0x84000013)
+#define PSCI_MEM_CHK_RANGE_AARCH32	U(0x84000014)
+#define PSCI_MEM_CHK_RANGE_AARCH64	U(0xc4000014)
 
 /* Macro to help build the psci capabilities bitfield */
 #define define_psci_cap(x)		(U(1) << (x & U(0x1f)))
@@ -288,6 +291,9 @@ typedef struct plat_psci_ops {
 				    unsigned int power_state,
 				    psci_power_state_t *output_state);
 	int (*get_node_hw_state)(u_register_t mpidr, unsigned int power_level);
+	int (*mem_protect_chk)(uintptr_t base, u_register_t length);
+	int (*read_mem_protect)(int *val);
+	int (*write_mem_protect)(int val);
 } plat_psci_ops_t;
 
 /*******************************************************************************

lib/psci/psci_lib.mk

@@ -17,6 +17,7 @@ PSCI_LIB_SOURCES	:=	lib/el3_runtime/cpu_data_array.c	\
 				lib/psci/psci_main.c			\
 				lib/psci/psci_setup.c			\
 				lib/psci/psci_system_off.c		\
+				lib/psci/psci_mem_protect.c		\
 				lib/psci/${ARCH}/psci_helpers.S
 
 ifeq (${ARCH}, aarch64)

lib/psci/psci_main.c

@@ -408,6 +408,11 @@ u_register_t psci_smc_handler(uint32_t smc_fid,
 		case PSCI_STAT_COUNT_AARCH32:
 			return psci_stat_count(x1, x2);
 #endif
+		case PSCI_MEM_PROTECT:
+			return psci_mem_protect(x1);
+
+		case PSCI_MEM_CHK_RANGE_AARCH32:
+			return psci_mem_chk_range(x1, x2);
 
 		default:
 			break;
@@ -445,6 +450,10 @@ u_register_t psci_smc_handler(uint32_t smc_fid,
 			return psci_stat_count(x1, x2);
 #endif
 
+		case PSCI_MEM_CHK_RANGE_AARCH64:
+			return psci_mem_chk_range(x1, x2);
+
+
 		default:
 			break;
 		}

lib/psci/psci_mem_protect.c

+/*
+ * 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;
+}

lib/psci/psci_private.h

@@ -269,4 +269,8 @@ u_register_t psci_stat_residency(u_register_t target_cpu,
 u_register_t psci_stat_count(u_register_t target_cpu,
 			unsigned int power_state);
 
+/* Private exported functions from psci_mem_protect.c */
+int psci_mem_protect(unsigned int enable);
+int psci_mem_chk_range(uintptr_t base, u_register_t length);
+
 #endif /* __PSCI_PRIVATE_H__ */

lib/psci/psci_setup.c

@@ -243,6 +243,11 @@ int psci_setup(const psci_lib_args_t *lib_args)
 		psci_caps |=  define_psci_cap(PSCI_SYSTEM_RESET);
 	if (psci_plat_pm_ops->get_node_hw_state)
 		psci_caps |= define_psci_cap(PSCI_NODE_HW_STATE_AARCH64);
+	if (psci_plat_pm_ops->read_mem_protect &&
+			psci_plat_pm_ops->write_mem_protect)
+		psci_caps |= define_psci_cap(PSCI_MEM_PROTECT);
+	if (psci_plat_pm_ops->mem_protect_chk)
+		psci_caps |= define_psci_cap(PSCI_MEM_CHK_RANGE_AARCH64);
 
 #if ENABLE_PSCI_STAT
 	psci_caps |=  define_psci_cap(PSCI_STAT_RESIDENCY_AARCH64);