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[freertos] / FreeRTOS / Source / portable / ARMv8M / non_secure / portable / GCC / ARM_CM23 / portasm.c
1 /*\r
2  * FreeRTOS Kernel V10.2.1\r
3  * Copyright (C) 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.\r
4  *\r
5  * Permission is hereby granted, free of charge, to any person obtaining a copy of\r
6  * this software and associated documentation files (the "Software"), to deal in\r
7  * the Software without restriction, including without limitation the rights to\r
8  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of\r
9  * the Software, and to permit persons to whom the Software is furnished to do so,\r
10  * subject to the following conditions:\r
11  *\r
12  * The above copyright notice and this permission notice shall be included in all\r
13  * copies or substantial portions of the Software.\r
14  *\r
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\r
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS\r
17  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR\r
18  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER\r
19  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN\r
20  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\r
21  *\r
22  * http://www.FreeRTOS.org\r
23  * http://aws.amazon.com/freertos\r
24  *\r
25  * 1 tab == 4 spaces!\r
26  */\r
27 \r
28 /* Standard includes. */\r
29 #include <stdint.h>\r
30 \r
31 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE ensures that PRIVILEGED_FUNCTION\r
32  * is defined correctly and privileged functions are placed in correct sections. */\r
33 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE\r
34 \r
35 /* Portasm includes. */\r
36 #include "portasm.h"\r
37 \r
38 /* MPU_WRAPPERS_INCLUDED_FROM_API_FILE is needed to be defined only for the\r
39  * header files. */\r
40 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE\r
41 \r
42 #if( configENABLE_FPU == 1 )\r
43         #error Cortex-M23 does not have a Floating Point Unit (FPU) and therefore configENABLE_FPU must be set to 0.\r
44 #endif\r
45 \r
46 void vRestoreContextOfFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */\r
47 {\r
48         __asm volatile\r
49         (\r
50         "       .syntax unified                                                                 \n"\r
51         "                                                                                                       \n"\r
52         "       ldr  r2, pxCurrentTCBConst2                                             \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */\r
53         "       ldr  r3, [r2]                                                                   \n" /* Read pxCurrentTCB. */\r
54         "       ldr  r0, [r3]                                                                   \n" /* Read top of stack from TCB - The first item in pxCurrentTCB is the task top of stack. */\r
55         "                                                                                                       \n"\r
56         #if( configENABLE_MPU == 1 )\r
57         "       dmb                                                                                             \n" /* Complete outstanding transfers before disabling MPU. */\r
58         "       ldr r2, xMPUCTRLConst2                                                  \n" /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
59         "       ldr r4, [r2]                                                                    \n" /* Read the value of MPU_CTRL. */\r
60         "       movs r5, #1                                                                             \n" /* r5 = 1. */\r
61         "       bics r4, r5                                                                             \n" /* r4 = r4 & ~r5 i.e. Clear the bit 0 in r4. */\r
62         "       str r4, [r2]                                                                    \n" /* Disable MPU. */\r
63         "                                                                                                       \n"\r
64         "       adds r3, #4                                                                             \n" /* r3 = r3 + 4. r3 now points to MAIR0 in TCB. */\r
65         "       ldr  r4, [r3]                                                                   \n" /* r4 = *r3 i.e. r4 = MAIR0. */\r
66         "       ldr  r2, xMAIR0Const2                                                   \n" /* r2 = 0xe000edc0 [Location of MAIR0]. */\r
67         "       str  r4, [r2]                                                                   \n" /* Program MAIR0. */\r
68         "       ldr  r2, xRNRConst2                                                             \n" /* r2 = 0xe000ed98 [Location of RNR]. */\r
69         "       adds r3, #4                                                                             \n" /* r3 = r3 + 4. r3 now points to first RBAR in TCB. */\r
70         "       movs r5, #4                                                                             \n" /* r5 = 4. */\r
71         "       str  r5, [r2]                                                                   \n" /* Program RNR = 4. */\r
72         "       ldmia r3!, {r6,r7}                                                              \n" /* Read first set of RBAR/RLAR from TCB. */\r
73         "       ldr  r4, xRBARConst2                                                    \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
74         "       stmia r4!, {r6,r7}                                                              \n" /* Write first set of RBAR/RLAR registers. */\r
75         "       movs r5, #5                                                                             \n" /* r5 = 5. */\r
76         "       str  r5, [r2]                                                                   \n" /* Program RNR = 5. */\r
77         "       ldmia r3!, {r6,r7}                                                              \n" /* Read second set of RBAR/RLAR from TCB. */\r
78         "       ldr  r4, xRBARConst2                                                    \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
79         "       stmia r4!, {r6,r7}                                                              \n" /* Write second set of RBAR/RLAR registers. */\r
80         "       movs r5, #6                                                                             \n" /* r5 = 6. */\r
81         "       str  r5, [r2]                                                                   \n" /* Program RNR = 6. */\r
82         "       ldmia r3!, {r6,r7}                                                              \n" /* Read third set of RBAR/RLAR from TCB. */\r
83         "       ldr  r4, xRBARConst2                                                    \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
84         "       stmia r4!, {r6,r7}                                                              \n" /* Write third set of RBAR/RLAR registers. */\r
85         "       movs r5, #7                                                                             \n" /* r5 = 7. */\r
86         "       str  r5, [r2]                                                                   \n" /* Program RNR = 7. */\r
87         "       ldmia r3!, {r6,r7}                                                              \n" /* Read fourth set of RBAR/RLAR from TCB. */\r
88         "       ldr  r4, xRBARConst2                                                    \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
89         "       stmia r4!, {r6,r7}                                                              \n" /* Write fourth set of RBAR/RLAR registers. */\r
90         "                                                                                                       \n"\r
91         "       ldr r2, xMPUCTRLConst2                                                  \n" /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
92         "       ldr r4, [r2]                                                                    \n" /* Read the value of MPU_CTRL. */\r
93         "       movs r5, #1                                                                             \n" /* r5 = 1. */\r
94         "       orrs r4, r5                                                                             \n" /* r4 = r4 | r5 i.e. Set the bit 0 in r4. */\r
95         "       str r4, [r2]                                                                    \n" /* Enable MPU. */\r
96         "       dsb                                                                                             \n" /* Force memory writes before continuing. */\r
97         #endif /* configENABLE_MPU */\r
98         "                                                                                                       \n"\r
99         #if( configENABLE_MPU == 1 )\r
100         "       ldm  r0!, {r1-r4}                                                               \n" /* Read from stack - r1 = xSecureContext, r2 = PSPLIM, r3 = CONTROL and r4 = EXC_RETURN. */\r
101         "       ldr  r5, xSecureContextConst2                                   \n"\r
102         "       str  r1, [r5]                                                                   \n" /* Set xSecureContext to this task's value for the same. */\r
103         "       msr  psplim, r2                                                                 \n" /* Set this task's PSPLIM value. */\r
104         "       msr  control, r3                                                                \n" /* Set this task's CONTROL value. */\r
105         "       adds r0, #32                                                                    \n" /* Discard everything up to r0. */\r
106         "       msr  psp, r0                                                                    \n" /* This is now the new top of stack to use in the task. */\r
107         "       isb                                                                                             \n"\r
108         "       bx   r4                                                                                 \n" /* Finally, branch to EXC_RETURN. */\r
109         #else /* configENABLE_MPU */\r
110         "       ldm  r0!, {r1-r3}                                                               \n" /* Read from stack - r1 = xSecureContext, r2 = PSPLIM and r3 = EXC_RETURN. */\r
111         "       ldr  r4, xSecureContextConst2                                   \n"\r
112         "       str  r1, [r4]                                                                   \n" /* Set xSecureContext to this task's value for the same. */\r
113         "       msr  psplim, r2                                                                 \n" /* Set this task's PSPLIM value. */\r
114         "       movs r1, #2                                                                             \n" /* r1 = 2. */\r
115         "       msr  CONTROL, r1                                                                \n" /* Switch to use PSP in the thread mode. */\r
116         "       adds r0, #32                                                                    \n" /* Discard everything up to r0. */\r
117         "       msr  psp, r0                                                                    \n" /* This is now the new top of stack to use in the task. */\r
118         "       isb                                                                                             \n"\r
119         "       bx   r3                                                                                 \n" /* Finally, branch to EXC_RETURN. */\r
120         #endif /* configENABLE_MPU */\r
121         "                                                                                                       \n"\r
122         "       .align 4                                                                                \n"\r
123         "pxCurrentTCBConst2: .word pxCurrentTCB                         \n"\r
124         "xSecureContextConst2: .word xSecureContext                     \n"\r
125         #if( configENABLE_MPU == 1 )\r
126         "xMPUCTRLConst2: .word 0xe000ed94                                       \n"\r
127         "xMAIR0Const2: .word 0xe000edc0                                         \n"\r
128         "xRNRConst2: .word 0xe000ed98                                           \n"\r
129         "xRBARConst2: .word 0xe000ed9c                                          \n"\r
130         #endif /* configENABLE_MPU */\r
131         );\r
132 }\r
133 /*-----------------------------------------------------------*/\r
134 \r
135 BaseType_t xIsPrivileged( void ) /* __attribute__ (( naked )) */\r
136 {\r
137         __asm volatile\r
138         (\r
139         "       mrs r0, control                                                                 \n" /* r0 = CONTROL. */\r
140         "       movs r1, #1                                                                             \n" /* r1 = 1. */\r
141         "       tst r0, r1                                                                              \n" /* Perform r0 & r1 (bitwise AND) and update the conditions flag. */\r
142         "       beq running_privileged                                                  \n" /* If the result of previous AND operation was 0, branch. */\r
143         "       movs r0, #0                                                                             \n" /* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */\r
144         "       bx lr                                                                                   \n" /* Return. */\r
145         " running_privileged:                                                           \n"\r
146         "       movs r0, #1                                                                             \n" /* CONTROL[0]==0. Return true to indicate that the processor is privileged. */\r
147         "       bx lr                                                                                   \n" /* Return. */\r
148         "                                                                                                       \n"\r
149         "       .align 4                                                                                \n"\r
150         ::: "r0", "r1", "memory"\r
151         );\r
152 }\r
153 /*-----------------------------------------------------------*/\r
154 \r
155 void vRaisePrivilege( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */\r
156 {\r
157          __asm volatile\r
158         (\r
159         "       mrs r0, control                                                                 \n" /* Read the CONTROL register. */\r
160         "       movs r1, #1                                                                             \n" /* r1 = 1. */\r
161         "       bics r0, r1                                                                             \n" /* Clear the bit 0. */\r
162         "       msr control, r0                                                                 \n" /* Write back the new CONTROL value. */\r
163         "       bx lr                                                                                   \n" /* Return to the caller. */\r
164         ::: "r0", "r1", "memory"\r
165         );\r
166 }\r
167 /*-----------------------------------------------------------*/\r
168 \r
169 void vResetPrivilege( void ) /* __attribute__ (( naked )) */\r
170 {\r
171         __asm volatile\r
172         (\r
173         "       mrs r0, control                                                                 \n" /* r0 = CONTROL. */\r
174         "       movs r1, #1                                                                             \n" /* r1 = 1. */\r
175         "       orrs r0, r1                                                                             \n" /* r0 = r0 | r1. */\r
176         "       msr control, r0                                                                 \n" /* CONTROL = r0. */\r
177         "       bx lr                                                                                   \n" /* Return to the caller. */\r
178         :::"r0", "r1", "memory"\r
179         );\r
180 }\r
181 /*-----------------------------------------------------------*/\r
182 \r
183 void vStartFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */\r
184 {\r
185         __asm volatile\r
186         (\r
187         "       ldr r0, xVTORConst                                                              \n" /* Use the NVIC offset register to locate the stack. */\r
188         "       ldr r0, [r0]                                                                    \n" /* Read the VTOR register which gives the address of vector table. */\r
189         "       ldr r0, [r0]                                                                    \n" /* The first entry in vector table is stack pointer. */\r
190         "       msr msp, r0                                                                             \n" /* Set the MSP back to the start of the stack. */\r
191         "       cpsie i                                                                                 \n" /* Globally enable interrupts. */\r
192         "       dsb                                                                                             \n"\r
193         "       isb                                                                                             \n"\r
194         "       svc %0                                                                                  \n" /* System call to start the first task. */\r
195         "       nop                                                                                             \n"\r
196         "                                                                                                       \n"\r
197         "   .align 4                                                                            \n"\r
198         "xVTORConst: .word 0xe000ed08                                           \n"\r
199         :: "i" ( portSVC_START_SCHEDULER ) : "memory"\r
200         );\r
201 }\r
202 /*-----------------------------------------------------------*/\r
203 \r
204 uint32_t ulSetInterruptMaskFromISR( void ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */\r
205 {\r
206         __asm volatile\r
207         (\r
208         "       mrs r0, PRIMASK                                                                 \n"\r
209         "       cpsid i                                                                                 \n"\r
210         "       bx lr                                                                                   \n"\r
211         ::: "memory"\r
212         );\r
213 }\r
214 /*-----------------------------------------------------------*/\r
215 \r
216 void vClearInterruptMaskFromISR( __attribute__( ( unused ) ) uint32_t ulMask ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */\r
217 {\r
218         __asm volatile\r
219         (\r
220         "       msr PRIMASK, r0                                                                 \n"\r
221         "       bx lr                                                                                   \n"\r
222         ::: "memory"\r
223         );\r
224 }\r
225 /*-----------------------------------------------------------*/\r
226 \r
227 void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */\r
228 {\r
229         __asm volatile\r
230         (\r
231         "       .syntax unified                                                                 \n"\r
232         "       .extern SecureContext_SaveContext                               \n"\r
233         "       .extern SecureContext_LoadContext                               \n"\r
234         "                                                                                                       \n"\r
235         "       mrs r1, psp                                                                             \n" /* Read PSP in r1. */\r
236         "       ldr r2, xSecureContextConst                                             \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */\r
237         "       ldr r0, [r2]                                                                    \n" /* Read xSecureContext - Value of xSecureContext must be in r0 as it is used as a parameter later. */\r
238         "                                                                                                       \n"\r
239         "       cbz r0, save_ns_context                                                 \n" /* No secure context to save. */\r
240         "       push {r0-r2, r14}                                                               \n"\r
241         "       bl SecureContext_SaveContext                                    \n"\r
242         "       pop {r0-r3}                                                                             \n" /* LR is now in r3. */\r
243         "       mov lr, r3                                                                              \n" /* LR = r3. */\r
244         "       lsls r2, r3, #25                                                                \n" /* r2 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */\r
245         "       bpl save_ns_context                                                             \n" /* bpl - branch if positive or zero. If r2 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */\r
246         "       ldr r3, pxCurrentTCBConst                                               \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */\r
247         "       ldr r2, [r3]                                                                    \n" /* Read pxCurrentTCB. */\r
248         #if( configENABLE_MPU == 1 )\r
249         "       subs r1, r1, #16                                                                \n" /* Make space for xSecureContext, PSPLIM, CONTROL and LR on the stack. */\r
250         "       str r1, [r2]                                                                    \n" /* Save the new top of stack in TCB. */\r
251         "       mrs r2, psplim                                                                  \n" /* r2 = PSPLIM. */\r
252         "       mrs r3, control                                                                 \n" /* r3 = CONTROL. */\r
253         "       mov r4, lr                                                                              \n" /* r4 = LR/EXC_RETURN. */\r
254         "       stmia r1!, {r0, r2-r4}                                                  \n" /* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */\r
255         #else /* configENABLE_MPU */\r
256         "       subs r1, r1, #12                                                                \n" /* Make space for xSecureContext, PSPLIM and LR on the stack. */\r
257         "       str r1, [r2]                                                                    \n" /* Save the new top of stack in TCB. */\r
258         "       mrs r2, psplim                                                                  \n" /* r2 = PSPLIM. */\r
259         "       mov r3, lr                                                                              \n" /* r3 = LR/EXC_RETURN. */\r
260         "       stmia r1!, {r0, r2-r3}                                                  \n" /* Store xSecureContext, PSPLIM and LR on the stack. */\r
261         #endif /* configENABLE_MPU */\r
262         "       b select_next_task                                                              \n"\r
263         "                                                                                                       \n"\r
264         " save_ns_context:                                                                      \n"\r
265         "       ldr r3, pxCurrentTCBConst                                               \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */\r
266         "       ldr r2, [r3]                                                                    \n" /* Read pxCurrentTCB. */\r
267         #if( configENABLE_MPU == 1 )\r
268         "       subs r1, r1, #48                                                                \n" /* Make space for xSecureContext, PSPLIM, CONTROL, LR and the remaining registers on the stack. */\r
269         "       str r1, [r2]                                                                    \n" /* Save the new top of stack in TCB. */\r
270         "       adds r1, r1, #16                                                                \n" /* r1 = r1 + 16. */\r
271         "       stmia r1!, {r4-r7}                                                              \n" /* Store the low registers that are not saved automatically. */\r
272         "       mov r4, r8                                                                              \n" /* r4 = r8. */\r
273         "       mov r5, r9                                                                              \n" /* r5 = r9. */\r
274         "       mov r6, r10                                                                             \n" /* r6 = r10. */\r
275         "       mov r7, r11                                                                             \n" /* r7 = r11. */\r
276         "       stmia r1!, {r4-r7}                                                              \n" /* Store the high registers that are not saved automatically. */\r
277         "       mrs r2, psplim                                                                  \n" /* r2 = PSPLIM. */\r
278         "       mrs r3, control                                                                 \n" /* r3 = CONTROL. */\r
279         "       mov r4, lr                                                                              \n" /* r4 = LR/EXC_RETURN. */\r
280         "       subs r1, r1, #48                                                                \n" /* r1 = r1 - 48. */\r
281         "       stmia r1!, {r0, r2-r4}                                                  \n" /* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */\r
282         #else /* configENABLE_MPU */\r
283         "       subs r1, r1, #44                                                                \n" /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */\r
284         "       str r1, [r2]                                                                    \n" /* Save the new top of stack in TCB. */\r
285         "       mrs r2, psplim                                                                  \n" /* r2 = PSPLIM. */\r
286         "       mov r3, lr                                                                              \n" /* r3 = LR/EXC_RETURN. */\r
287         "       stmia r1!, {r0, r2-r7}                                                  \n" /* Store xSecureContext, PSPLIM, LR and the low registers that are not saved automatically. */\r
288         "       mov r4, r8                                                                              \n" /* r4 = r8. */\r
289         "       mov r5, r9                                                                              \n" /* r5 = r9. */\r
290         "       mov r6, r10                                                                             \n" /* r6 = r10. */\r
291         "       mov r7, r11                                                                             \n" /* r7 = r11. */\r
292         "       stmia r1!, {r4-r7}                                                              \n" /* Store the high registers that are not saved automatically. */\r
293         #endif /* configENABLE_MPU */\r
294         "                                                                                                       \n"\r
295         " select_next_task:                                                                     \n"\r
296         "       cpsid i                                                                                 \n"\r
297         "       bl vTaskSwitchContext                                                   \n"\r
298         "       cpsie i                                                                                 \n"\r
299         "                                                                                                       \n"\r
300         "       ldr r2, pxCurrentTCBConst                                               \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */\r
301         "       ldr r3, [r2]                                                                    \n" /* Read pxCurrentTCB. */\r
302         "       ldr r1, [r3]                                                                    \n" /* The first item in pxCurrentTCB is the task top of stack. r1 now points to the top of stack. */\r
303         "                                                                                                       \n"\r
304         #if( configENABLE_MPU == 1 )\r
305         "       dmb                                                                                             \n" /* Complete outstanding transfers before disabling MPU. */\r
306         "       ldr r2, xMPUCTRLConst                                                   \n" /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
307         "       ldr r4, [r2]                                                                    \n" /* Read the value of MPU_CTRL. */\r
308         "       movs r5, #1                                                                             \n" /* r5 = 1. */\r
309         "       bics r4, r5                                                                             \n" /* r4 = r4 & ~r5 i.e. Clear the bit 0 in r4. */\r
310         "       str r4, [r2]                                                                    \n" /* Disable MPU. */\r
311         "                                                                                                       \n"\r
312         "       adds r3, #4                                                                             \n" /* r3 = r3 + 4. r3 now points to MAIR0 in TCB. */\r
313         "       ldr r4, [r3]                                                                    \n" /* r4 = *r3 i.e. r4 = MAIR0. */\r
314         "       ldr r2, xMAIR0Const                                                             \n" /* r2 = 0xe000edc0 [Location of MAIR0]. */\r
315         "       str r4, [r2]                                                                    \n" /* Program MAIR0. */\r
316         "       ldr r2, xRNRConst                                                               \n" /* r2 = 0xe000ed98 [Location of RNR]. */\r
317         "       adds r3, #4                                                                             \n" /* r3 = r3 + 4. r3 now points to first RBAR in TCB. */\r
318         "       movs r5, #4                                                                             \n" /* r5 = 4. */\r
319         "       str  r5, [r2]                                                                   \n" /* Program RNR = 4. */\r
320         "       ldmia r3!, {r6,r7}                                                              \n" /* Read first set of RBAR/RLAR from TCB. */\r
321         "       ldr  r4, xRBARConst                                                             \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
322         "       stmia r4!, {r6,r7}                                                              \n" /* Write first set of RBAR/RLAR registers. */\r
323         "       movs r5, #5                                                                             \n" /* r5 = 5. */\r
324         "       str  r5, [r2]                                                                   \n" /* Program RNR = 5. */\r
325         "       ldmia r3!, {r6,r7}                                                              \n" /* Read second set of RBAR/RLAR from TCB. */\r
326         "       ldr  r4, xRBARConst                                                             \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
327         "       stmia r4!, {r6,r7}                                                              \n" /* Write second set of RBAR/RLAR registers. */\r
328         "       movs r5, #6                                                                             \n" /* r5 = 6. */\r
329         "       str  r5, [r2]                                                                   \n" /* Program RNR = 6. */\r
330         "       ldmia r3!, {r6,r7}                                                              \n" /* Read third set of RBAR/RLAR from TCB. */\r
331         "       ldr  r4, xRBARConst                                                             \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
332         "       stmia r4!, {r6,r7}                                                              \n" /* Write third set of RBAR/RLAR registers. */\r
333         "       movs r5, #7                                                                             \n" /* r5 = 7. */\r
334         "       str  r5, [r2]                                                                   \n" /* Program RNR = 7. */\r
335         "       ldmia r3!, {r6,r7}                                                              \n" /* Read fourth set of RBAR/RLAR from TCB. */\r
336         "       ldr  r4, xRBARConst                                                             \n" /* r4 = 0xe000ed9c [Location of RBAR]. */\r
337         "       stmia r4!, {r6,r7}                                                              \n" /* Write fourth set of RBAR/RLAR registers. */\r
338         "                                                                                                       \n"\r
339         "       ldr r2, xMPUCTRLConst                                                   \n" /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
340         "       ldr r4, [r2]                                                                    \n" /* Read the value of MPU_CTRL. */\r
341         "       movs r5, #1                                                                             \n" /* r5 = 1. */\r
342         "       orrs r4, r5                                                                             \n" /* r4 = r4 | r5 i.e. Set the bit 0 in r4. */\r
343         "       str r4, [r2]                                                                    \n" /* Enable MPU. */\r
344         "       dsb                                                                                             \n" /* Force memory writes before continuing. */\r
345         #endif /* configENABLE_MPU */\r
346         "                                                                                                       \n"\r
347         #if( configENABLE_MPU == 1 )\r
348         "       ldmia r1!, {r0, r2-r4}                                                  \n" /* Read from stack - r0 = xSecureContext, r2 = PSPLIM, r3 = CONTROL and r4 = LR. */\r
349         "       msr psplim, r2                                                                  \n" /* Restore the PSPLIM register value for the task. */\r
350         "       msr control, r3                                                                 \n" /* Restore the CONTROL register value for the task. */\r
351         "       mov lr, r4                                                                              \n" /* LR = r4. */\r
352         "       ldr r2, xSecureContextConst                                             \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */\r
353         "       str r0, [r2]                                                                    \n" /* Restore the task's xSecureContext. */\r
354         "       cbz r0, restore_ns_context                                              \n" /* If there is no secure context for the task, restore the non-secure context. */\r
355         "       push {r1,r4}                                                                    \n"\r
356         "       bl SecureContext_LoadContext                                    \n" /* Restore the secure context. */\r
357         "       pop {r1,r4}                                                                             \n"\r
358         "       mov lr, r4                                                                              \n" /* LR = r4. */\r
359         "       lsls r2, r4, #25                                                                \n" /* r2 = r4 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */\r
360         "       bpl restore_ns_context                                                  \n" /* bpl - branch if positive or zero. If r2 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */\r
361         "       msr psp, r1                                                                             \n" /* Remember the new top of stack for the task. */\r
362         "       bx lr                                                                                   \n"\r
363         #else /* configENABLE_MPU */\r
364         "       ldmia r1!, {r0, r2-r3}                                                  \n" /* Read from stack - r0 = xSecureContext, r2 = PSPLIM and r3 = LR. */\r
365         "       msr psplim, r2                                                                  \n" /* Restore the PSPLIM register value for the task. */\r
366         "       mov lr, r3                                                                              \n" /* LR = r3. */\r
367         "       ldr r2, xSecureContextConst                                             \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */\r
368         "       str r0, [r2]                                                                    \n" /* Restore the task's xSecureContext. */\r
369         "       cbz r0, restore_ns_context                                              \n" /* If there is no secure context for the task, restore the non-secure context. */\r
370         "       push {r1,r3}                                                                    \n"\r
371         "       bl SecureContext_LoadContext                                    \n" /* Restore the secure context. */\r
372         "       pop {r1,r3}                                                                             \n"\r
373         "       mov lr, r3                                                                              \n" /* LR = r3. */\r
374         "       lsls r2, r3, #25                                                                \n" /* r2 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */\r
375         "       bpl restore_ns_context                                                  \n" /* bpl - branch if positive or zero. If r2 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */\r
376         "       msr psp, r1                                                                             \n" /* Remember the new top of stack for the task. */\r
377         "       bx lr                                                                                   \n"\r
378         #endif /* configENABLE_MPU */\r
379         "                                                                                                       \n"\r
380         " restore_ns_context:                                                           \n"\r
381         "       adds r1, r1, #16                                                                \n" /* Move to the high registers. */\r
382         "       ldmia r1!, {r4-r7}                                                              \n" /* Restore the high registers that are not automatically restored. */\r
383         "       mov r8, r4                                                                              \n" /* r8 = r4. */\r
384         "       mov r9, r5                                                                              \n" /* r9 = r5. */\r
385         "       mov r10, r6                                                                             \n" /* r10 = r6. */\r
386         "       mov r11, r7                                                                             \n" /* r11 = r7. */\r
387         "       msr psp, r1                                                                             \n" /* Remember the new top of stack for the task. */\r
388         "       subs r1, r1, #32                                                                \n" /* Go back to the low registers. */\r
389         "       ldmia r1!, {r4-r7}                                                              \n" /* Restore the low registers that are not automatically restored. */\r
390         "       bx lr                                                                                   \n"\r
391         "                                                                                                       \n"\r
392         "       .align 4                                                                                \n"\r
393         "pxCurrentTCBConst: .word pxCurrentTCB                          \n"\r
394         "xSecureContextConst: .word xSecureContext                      \n"\r
395         #if( configENABLE_MPU == 1 )\r
396         "xMPUCTRLConst: .word 0xe000ed94                                        \n"\r
397         "xMAIR0Const: .word 0xe000edc0                                          \n"\r
398         "xRNRConst: .word 0xe000ed98                                            \n"\r
399         "xRBARConst: .word 0xe000ed9c                                           \n"\r
400         #endif /* configENABLE_MPU */\r
401         );\r
402 }\r
403 /*-----------------------------------------------------------*/\r
404 \r
405 void SVC_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */\r
406 {\r
407         __asm volatile\r
408         (\r
409         "       movs r0, #4                                                                             \n"\r
410         "       mov r1, lr                                                                              \n"\r
411         "       tst r0, r1                                                                              \n"\r
412         "       beq stacking_used_msp                                                   \n"\r
413         "       mrs r0, psp                                                                             \n"\r
414         "       ldr r2, svchandler_address_const                                \n"\r
415         "       bx r2                                                                                   \n"\r
416         " stacking_used_msp:                                                            \n"\r
417         "       mrs r0, msp                                                                             \n"\r
418         "       ldr r2, svchandler_address_const                                \n"\r
419         "       bx r2                                                                                   \n"\r
420         "                                                                                                       \n"\r
421         "       .align 4                                                                                \n"\r
422         "svchandler_address_const: .word vPortSVCHandler_C      \n"\r
423         );\r
424 }\r
425 /*-----------------------------------------------------------*/\r
426 \r
427 void vPortAllocateSecureContext( uint32_t ulSecureStackSize ) /* __attribute__ (( naked )) */\r
428 {\r
429         __asm volatile\r
430         (\r
431         "       svc %0                                                                                  \n" /* Secure context is allocated in the supervisor call. */\r
432         "       bx lr                                                                                   \n" /* Return. */\r
433         :: "i" ( portSVC_ALLOCATE_SECURE_CONTEXT ) : "memory"\r
434         );\r
435 }\r
436 /*-----------------------------------------------------------*/\r
437 \r
438 void vPortFreeSecureContext( uint32_t *pulTCB ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */\r
439 {\r
440         __asm volatile\r
441         (\r
442         "       ldr r1, [r0]                                                                    \n" /* The first item in the TCB is the top of the stack. */\r
443         "       ldr r0, [r1]                                                                    \n" /* The first item on the stack is the task's xSecureContext. */\r
444         "       cmp r0, #0                                                                              \n" /* Raise svc if task's xSecureContext is not NULL. */\r
445         "       beq free_secure_context                                                 \n"\r
446         "       bx lr                                                                                   \n" /* There is no secure context (xSecureContext is NULL). */\r
447         " free_secure_context:                                                          \n"\r
448         "       svc %0                                                                                  \n" /* Secure context is freed in the supervisor call. */\r
449         "       bx lr                                                                                   \n" /* Return. */\r
450         :: "i" ( portSVC_FREE_SECURE_CONTEXT ) : "memory"\r
451         );\r
452 }\r
453 /*-----------------------------------------------------------*/\r