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| Rev | Author | Line No. | Line |
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| 2 | mjames | 1 | /****************************************************************************** |
| 2 | * @file tz_context.c |
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| 3 | * @brief Context Management for Armv8-M TrustZone - Sample implementation |
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| 4 | * @version V1.1.1 |
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| 5 | * @date 10. January 2018 |
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| 6 | ******************************************************************************/ |
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| 7 | /* |
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| 8 | * Copyright (c) 2016-2018 Arm Limited. All rights reserved. |
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| 9 | * |
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| 10 | * SPDX-License-Identifier: Apache-2.0 |
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| 11 | * |
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| 12 | * Licensed under the Apache License, Version 2.0 (the License); you may |
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| 13 | * not use this file except in compliance with the License. |
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| 14 | * You may obtain a copy of the License at |
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| 15 | * |
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| 16 | * www.apache.org/licenses/LICENSE-2.0 |
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| 17 | * |
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| 18 | * Unless required by applicable law or agreed to in writing, software |
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| 19 | * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
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| 20 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 21 | * See the License for the specific language governing permissions and |
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| 22 | * limitations under the License. |
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| 23 | */ |
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| 24 | |||
| 25 | #include "RTE_Components.h" |
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| 26 | #include CMSIS_device_header |
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| 27 | #include "tz_context.h" |
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| 28 | |||
| 29 | /// Number of process slots (threads may call secure library code) |
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| 30 | #ifndef TZ_PROCESS_STACK_SLOTS |
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| 31 | #define TZ_PROCESS_STACK_SLOTS 8U |
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| 32 | #endif |
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| 33 | |||
| 34 | /// Stack size of the secure library code |
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| 35 | #ifndef TZ_PROCESS_STACK_SIZE |
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| 36 | #define TZ_PROCESS_STACK_SIZE 256U |
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| 37 | #endif |
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| 38 | |||
| 39 | typedef struct { |
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| 40 | uint32_t sp_top; // stack space top |
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| 41 | uint32_t sp_limit; // stack space limit |
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| 42 | uint32_t sp; // current stack pointer |
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| 43 | } stack_info_t; |
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| 44 | |||
| 45 | static stack_info_t ProcessStackInfo [TZ_PROCESS_STACK_SLOTS]; |
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| 46 | static uint64_t ProcessStackMemory[TZ_PROCESS_STACK_SLOTS][TZ_PROCESS_STACK_SIZE/8U]; |
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| 47 | static uint32_t ProcessStackFreeSlot = 0xFFFFFFFFU; |
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| 48 | |||
| 49 | |||
| 50 | /// Initialize secure context memory system |
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| 51 | /// \return execution status (1: success, 0: error) |
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| 52 | __attribute__((cmse_nonsecure_entry)) |
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| 53 | uint32_t TZ_InitContextSystem_S (void) { |
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| 54 | uint32_t n; |
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| 55 | |||
| 56 | if (__get_IPSR() == 0U) { |
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| 57 | return 0U; // Thread Mode |
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| 58 | } |
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| 59 | |||
| 60 | for (n = 0U; n < TZ_PROCESS_STACK_SLOTS; n++) { |
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| 61 | ProcessStackInfo[n].sp = 0U; |
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| 62 | ProcessStackInfo[n].sp_limit = (uint32_t)&ProcessStackMemory[n]; |
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| 63 | ProcessStackInfo[n].sp_top = (uint32_t)&ProcessStackMemory[n] + TZ_PROCESS_STACK_SIZE; |
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| 64 | *((uint32_t *)ProcessStackMemory[n]) = n + 1U; |
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| 65 | } |
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| 66 | *((uint32_t *)ProcessStackMemory[--n]) = 0xFFFFFFFFU; |
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| 67 | |||
| 68 | ProcessStackFreeSlot = 0U; |
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| 69 | |||
| 70 | // Default process stack pointer and stack limit |
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| 71 | __set_PSPLIM((uint32_t)ProcessStackMemory); |
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| 72 | __set_PSP ((uint32_t)ProcessStackMemory); |
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| 73 | |||
| 74 | // Privileged Thread Mode using PSP |
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| 75 | __set_CONTROL(0x02U); |
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| 76 | |||
| 77 | return 1U; // Success |
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| 78 | } |
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| 79 | |||
| 80 | |||
| 81 | /// Allocate context memory for calling secure software modules in TrustZone |
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| 82 | /// \param[in] module identifies software modules called from non-secure mode |
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| 83 | /// \return value != 0 id TrustZone memory slot identifier |
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| 84 | /// \return value 0 no memory available or internal error |
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| 85 | __attribute__((cmse_nonsecure_entry)) |
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| 86 | TZ_MemoryId_t TZ_AllocModuleContext_S (TZ_ModuleId_t module) { |
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| 87 | uint32_t slot; |
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| 88 | |||
| 89 | (void)module; // Ignore (fixed Stack size) |
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| 90 | |||
| 91 | if (__get_IPSR() == 0U) { |
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| 92 | return 0U; // Thread Mode |
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| 93 | } |
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| 94 | |||
| 95 | if (ProcessStackFreeSlot == 0xFFFFFFFFU) { |
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| 96 | return 0U; // No slot available |
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| 97 | } |
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| 98 | |||
| 99 | slot = ProcessStackFreeSlot; |
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| 100 | ProcessStackFreeSlot = *((uint32_t *)ProcessStackMemory[slot]); |
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| 101 | |||
| 102 | ProcessStackInfo[slot].sp = ProcessStackInfo[slot].sp_top; |
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| 103 | |||
| 104 | return (slot + 1U); |
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| 105 | } |
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| 106 | |||
| 107 | |||
| 108 | /// Free context memory that was previously allocated with \ref TZ_AllocModuleContext_S |
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| 109 | /// \param[in] id TrustZone memory slot identifier |
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| 110 | /// \return execution status (1: success, 0: error) |
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| 111 | __attribute__((cmse_nonsecure_entry)) |
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| 112 | uint32_t TZ_FreeModuleContext_S (TZ_MemoryId_t id) { |
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| 113 | uint32_t slot; |
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| 114 | |||
| 115 | if (__get_IPSR() == 0U) { |
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| 116 | return 0U; // Thread Mode |
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| 117 | } |
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| 118 | |||
| 119 | if ((id == 0U) || (id > TZ_PROCESS_STACK_SLOTS)) { |
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| 120 | return 0U; // Invalid ID |
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| 121 | } |
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| 122 | |||
| 123 | slot = id - 1U; |
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| 124 | |||
| 125 | if (ProcessStackInfo[slot].sp == 0U) { |
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| 126 | return 0U; // Inactive slot |
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| 127 | } |
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| 128 | ProcessStackInfo[slot].sp = 0U; |
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| 129 | |||
| 130 | *((uint32_t *)ProcessStackMemory[slot]) = ProcessStackFreeSlot; |
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| 131 | ProcessStackFreeSlot = slot; |
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| 132 | |||
| 133 | return 1U; // Success |
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| 134 | } |
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| 135 | |||
| 136 | |||
| 137 | /// Load secure context (called on RTOS thread context switch) |
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| 138 | /// \param[in] id TrustZone memory slot identifier |
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| 139 | /// \return execution status (1: success, 0: error) |
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| 140 | __attribute__((cmse_nonsecure_entry)) |
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| 141 | uint32_t TZ_LoadContext_S (TZ_MemoryId_t id) { |
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| 142 | uint32_t slot; |
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| 143 | |||
| 144 | if ((__get_IPSR() == 0U) || ((__get_CONTROL() & 2U) == 0U)) { |
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| 145 | return 0U; // Thread Mode or using Main Stack for threads |
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| 146 | } |
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| 147 | |||
| 148 | if ((id == 0U) || (id > TZ_PROCESS_STACK_SLOTS)) { |
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| 149 | return 0U; // Invalid ID |
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| 150 | } |
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| 151 | |||
| 152 | slot = id - 1U; |
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| 153 | |||
| 154 | if (ProcessStackInfo[slot].sp == 0U) { |
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| 155 | return 0U; // Inactive slot |
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| 156 | } |
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| 157 | |||
| 158 | // Setup process stack pointer and stack limit |
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| 159 | __set_PSPLIM(ProcessStackInfo[slot].sp_limit); |
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| 160 | __set_PSP (ProcessStackInfo[slot].sp); |
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| 161 | |||
| 162 | return 1U; // Success |
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| 163 | } |
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| 164 | |||
| 165 | |||
| 166 | /// Store secure context (called on RTOS thread context switch) |
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| 167 | /// \param[in] id TrustZone memory slot identifier |
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| 168 | /// \return execution status (1: success, 0: error) |
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| 169 | __attribute__((cmse_nonsecure_entry)) |
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| 170 | uint32_t TZ_StoreContext_S (TZ_MemoryId_t id) { |
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| 171 | uint32_t slot; |
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| 172 | uint32_t sp; |
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| 173 | |||
| 174 | if ((__get_IPSR() == 0U) || ((__get_CONTROL() & 2U) == 0U)) { |
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| 175 | return 0U; // Thread Mode or using Main Stack for threads |
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| 176 | } |
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| 177 | |||
| 178 | if ((id == 0U) || (id > TZ_PROCESS_STACK_SLOTS)) { |
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| 179 | return 0U; // Invalid ID |
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| 180 | } |
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| 181 | |||
| 182 | slot = id - 1U; |
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| 183 | |||
| 184 | if (ProcessStackInfo[slot].sp == 0U) { |
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| 185 | return 0U; // Inactive slot |
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| 186 | } |
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| 187 | |||
| 188 | sp = __get_PSP(); |
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| 189 | if ((sp < ProcessStackInfo[slot].sp_limit) || |
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| 190 | (sp > ProcessStackInfo[slot].sp_top)) { |
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| 191 | return 0U; // SP out of range |
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| 192 | } |
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| 193 | ProcessStackInfo[slot].sp = sp; |
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| 194 | |||
| 195 | // Default process stack pointer and stack limit |
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| 196 | __set_PSPLIM((uint32_t)ProcessStackMemory); |
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| 197 | __set_PSP ((uint32_t)ProcessStackMemory); |
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| 198 | |||
| 199 | return 1U; // Success |
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| 200 | } |