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[freertos] / FreeRTOS / Source / portable / ARMv8M / non_secure / portable / IAR / ARM_CM23_NTZ / portasm.s
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         EXTERN pxCurrentTCB\r
29         EXTERN vTaskSwitchContext\r
30         EXTERN vPortSVCHandler_C\r
31 \r
32         PUBLIC xIsPrivileged\r
33         PUBLIC vResetPrivilege\r
34         PUBLIC vRestoreContextOfFirstTask\r
35         PUBLIC vRaisePrivilege\r
36         PUBLIC vStartFirstTask\r
37         PUBLIC ulSetInterruptMaskFromISR\r
38         PUBLIC vClearInterruptMaskFromISR\r
39         PUBLIC PendSV_Handler\r
40         PUBLIC SVC_Handler\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 \r
47 /*---------------- Unprivileged Functions -------------------*/\r
48 \r
49 /*-----------------------------------------------------------*/\r
50 \r
51         SECTION .text:CODE:NOROOT(2)\r
52         THUMB\r
53 /*-----------------------------------------------------------*/\r
54 \r
55 xIsPrivileged:\r
56         mrs r0, control                                                 /* r0 = CONTROL. */\r
57         movs r1, #1                                                             /* r1 = 1. */\r
58         tst r0, r1                                                              /* Perform r0 & r1 (bitwise AND) and update the conditions flag. */\r
59         beq running_privileged                                  /* If the result of previous AND operation was 0, branch. */\r
60         movs r0, #0                                                             /* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */\r
61         bx lr                                                                   /* Return. */\r
62         running_privileged:\r
63                 movs r0, #1                                                     /* CONTROL[0]==0. Return true to indicate that the processor is privileged. */\r
64                 bx lr                                                           /* Return. */\r
65 \r
66 /*-----------------------------------------------------------*/\r
67 \r
68 vResetPrivilege:\r
69         mrs r0, control                                                 /* r0 = CONTROL. */\r
70         movs r1, #1                                                             /* r1 = 1. */\r
71         orrs r0, r1                                                             /* r0 = r0 | r1. */\r
72         msr control, r0                                                 /* CONTROL = r0. */\r
73         bx lr                                                                   /* Return to the caller. */\r
74 /*-----------------------------------------------------------*/\r
75 \r
76 /*----------------- Privileged Functions --------------------*/\r
77 \r
78 /*-----------------------------------------------------------*/\r
79 \r
80         SECTION privileged_functions:CODE:NOROOT(2)\r
81         THUMB\r
82 /*-----------------------------------------------------------*/\r
83 \r
84 vRestoreContextOfFirstTask:\r
85         ldr  r2, =pxCurrentTCB                                  /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */\r
86         ldr  r1, [r2]                                                   /* Read pxCurrentTCB. */\r
87         ldr  r0, [r1]                                                   /* Read top of stack from TCB - The first item in pxCurrentTCB is the task top of stack. */\r
88 \r
89 #if ( configENABLE_MPU == 1 )\r
90         dmb                                                                             /* Complete outstanding transfers before disabling MPU. */\r
91         ldr r2, =0xe000ed94                                             /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
92         ldr r3, [r2]                                                    /* Read the value of MPU_CTRL. */\r
93         movs r4, #1                                                             /* r4 = 1. */\r
94         bics r3, r4                                                             /* r3 = r3 & ~r4 i.e. Clear the bit 0 in r3. */\r
95         str r3, [r2]                                                    /* Disable MPU. */\r
96 \r
97         adds r1, #4                                                             /* r1 = r1 + 4. r1 now points to MAIR0 in TCB. */\r
98         ldr  r4, [r1]                                                   /* r4 = *r1 i.e. r4 = MAIR0. */\r
99         ldr  r2, =0xe000edc0                                    /* r2 = 0xe000edc0 [Location of MAIR0]. */\r
100         str  r4, [r2]                                                   /* Program MAIR0. */\r
101         ldr  r2, =0xe000ed98                                    /* r2 = 0xe000ed98 [Location of RNR]. */\r
102         adds r1, #4                                                             /* r1 = r1 + 4. r1 now points to first RBAR in TCB. */\r
103         movs r4, #4                                                             /* r4 = 4. */\r
104         str  r4, [r2]                                                   /* Program RNR = 4. */\r
105         ldmia r1!, {r5,r6}                                              /* Read first set of RBAR/RLAR from TCB. */\r
106         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
107         stmia r3!, {r5,r6}                                              /* Write first set of RBAR/RLAR registers. */\r
108         movs r4, #5                                                             /* r4 = 5. */\r
109         str  r4, [r2]                                                   /* Program RNR = 5. */\r
110         ldmia r1!, {r5,r6}                                              /* Read second set of RBAR/RLAR from TCB. */\r
111         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
112         stmia r3!, {r5,r6}                                              /* Write second set of RBAR/RLAR registers. */\r
113         movs r4, #6                                                             /* r4 = 6. */\r
114         str  r4, [r2]                                                   /* Program RNR = 6. */\r
115         ldmia r1!, {r5,r6}                                              /* Read third set of RBAR/RLAR from TCB. */\r
116         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
117         stmia r3!, {r5,r6}                                              /* Write third set of RBAR/RLAR registers. */\r
118         movs r4, #7                                                             /* r4 = 7. */\r
119         str  r4, [r2]                                                   /* Program RNR = 7. */\r
120         ldmia r1!, {r5,r6}                                              /* Read fourth set of RBAR/RLAR from TCB. */\r
121         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
122         stmia r3!, {r5,r6}                                              /* Write fourth set of RBAR/RLAR registers. */\r
123 \r
124         ldr r2, =0xe000ed94                                             /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
125         ldr r3, [r2]                                                    /* Read the value of MPU_CTRL. */\r
126         movs r4, #1                                                             /* r4 = 1. */\r
127         orrs r3, r4                                                             /* r3 = r3 | r4 i.e. Set the bit 0 in r3. */\r
128         str r3, [r2]                                                    /* Enable MPU. */\r
129         dsb                                                                             /* Force memory writes before continuing. */\r
130 #endif /* configENABLE_MPU */\r
131 \r
132 #if ( configENABLE_MPU == 1 )\r
133         ldm  r0!, {r1-r3}                                               /* Read from stack - r1 = PSPLIM, r2 = CONTROL and r3 = EXC_RETURN. */\r
134         msr  psplim, r1                                                 /* Set this task's PSPLIM value. */\r
135         msr  control, r2                                                /* Set this task's CONTROL value. */\r
136         adds r0, #32                                                    /* Discard everything up to r0. */\r
137         msr  psp, r0                                                    /* This is now the new top of stack to use in the task. */\r
138         isb\r
139         bx   r3                                                                 /* Finally, branch to EXC_RETURN. */\r
140 #else /* configENABLE_MPU */\r
141         ldm  r0!, {r1-r2}                                               /* Read from stack - r1 = PSPLIM and r2 = EXC_RETURN. */\r
142         msr  psplim, r1                                                 /* Set this task's PSPLIM value. */\r
143         movs r1, #2                                                             /* r1 = 2. */\r
144         msr  CONTROL, r1                                                /* Switch to use PSP in the thread mode. */\r
145         adds r0, #32                                                    /* Discard everything up to r0. */\r
146         msr  psp, r0                                                    /* This is now the new top of stack to use in the task. */\r
147         isb\r
148         bx   r2                                                                 /* Finally, branch to EXC_RETURN. */\r
149 #endif /* configENABLE_MPU */\r
150 /*-----------------------------------------------------------*/\r
151 \r
152 vRaisePrivilege:\r
153         mrs  r0, control                                                /* Read the CONTROL register. */\r
154         movs r1, #1                                                             /* r1 = 1. */\r
155         bics r0, r1                                                             /* Clear the bit 0. */\r
156         msr  control, r0                                                /* Write back the new CONTROL value. */\r
157         bx lr                                                                   /* Return to the caller. */\r
158 /*-----------------------------------------------------------*/\r
159 \r
160 vStartFirstTask:\r
161         ldr r0, =0xe000ed08                                             /* Use the NVIC offset register to locate the stack. */\r
162         ldr r0, [r0]                                                    /* Read the VTOR register which gives the address of vector table. */\r
163         ldr r0, [r0]                                                    /* The first entry in vector table is stack pointer. */\r
164         msr msp, r0                                                             /* Set the MSP back to the start of the stack. */\r
165         cpsie i                                                                 /* Globally enable interrupts. */\r
166         dsb\r
167         isb\r
168         svc 2                                                                   /* System call to start the first task. portSVC_START_SCHEDULER = 2. */\r
169         nop\r
170 /*-----------------------------------------------------------*/\r
171 \r
172 ulSetInterruptMaskFromISR:\r
173         mrs r0, PRIMASK\r
174         cpsid i\r
175         bx lr\r
176 /*-----------------------------------------------------------*/\r
177 \r
178 vClearInterruptMaskFromISR:\r
179         msr PRIMASK, r0\r
180         bx lr\r
181 /*-----------------------------------------------------------*/\r
182 \r
183 PendSV_Handler:\r
184         mrs r0, psp                                                             /* Read PSP in r0. */\r
185         ldr r2, =pxCurrentTCB                                   /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */\r
186         ldr r1, [r2]                                                    /* Read pxCurrentTCB. */\r
187 #if ( configENABLE_MPU == 1 )\r
188         subs r0, r0, #44                                                /* Make space for PSPLIM, CONTROL, LR and the remaining registers on the stack. */\r
189         str r0, [r1]                                                    /* Save the new top of stack in TCB. */\r
190         mrs r1, psplim                                                  /* r1 = PSPLIM. */\r
191         mrs r2, control                                                 /* r2 = CONTROL. */\r
192         mov r3, lr                                                              /* r3 = LR/EXC_RETURN. */\r
193         stmia r0!, {r1-r7}                                              /* Store on the stack - PSPLIM, CONTROL, LR and low registers that are not automatically saved. */\r
194         mov r4, r8                                                              /* r4 = r8. */\r
195         mov r5, r9                                                              /* r5 = r9. */\r
196         mov r6, r10                                                             /* r6 = r10. */\r
197         mov r7, r11                                                             /* r7 = r11. */\r
198         stmia r0!, {r4-r7}                                              /* Store the high registers that are not saved automatically. */\r
199 #else /* configENABLE_MPU */\r
200         subs r0, r0, #40                                                /* Make space for PSPLIM, LR and the remaining registers on the stack. */\r
201         str r0, [r1]                                                    /* Save the new top of stack in TCB. */\r
202         mrs r2, psplim                                                  /* r2 = PSPLIM. */\r
203         mov r3, lr                                                              /* r3 = LR/EXC_RETURN. */\r
204         stmia r0!, {r2-r7}                                              /* Store on the stack - PSPLIM, LR and low registers that are not automatically saved. */\r
205         mov r4, r8                                                              /* r4 = r8. */\r
206         mov r5, r9                                                              /* r5 = r9. */\r
207         mov r6, r10                                                             /* r6 = r10. */\r
208         mov r7, r11                                                             /* r7 = r11. */\r
209         stmia r0!, {r4-r7}                                              /* Store the high registers that are not saved automatically. */\r
210 #endif /* configENABLE_MPU */\r
211 \r
212         cpsid i\r
213         bl vTaskSwitchContext\r
214         cpsie i\r
215 \r
216         ldr r2, =pxCurrentTCB                                   /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */\r
217         ldr r1, [r2]                                                    /* Read pxCurrentTCB. */\r
218         ldr r0, [r1]                                                    /* The first item in pxCurrentTCB is the task top of stack. r0 now points to the top of stack. */\r
219 \r
220 #if ( configENABLE_MPU == 1 )\r
221         dmb                                                                             /* Complete outstanding transfers before disabling MPU. */\r
222         ldr r2, =0xe000ed94                                             /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
223         ldr r3, [r2]                                                    /* Read the value of MPU_CTRL. */\r
224         movs r4, #1                                                             /* r4 = 1. */\r
225         bics r3, r4                                                             /* r3 = r3 & ~r4 i.e. Clear the bit 0 in r3. */\r
226         str r3, [r2]                                                    /* Disable MPU. */\r
227 \r
228         adds r1, #4                                                             /* r1 = r1 + 4. r1 now points to MAIR0 in TCB. */\r
229         ldr  r4, [r1]                                                   /* r4 = *r1 i.e. r4 = MAIR0. */\r
230         ldr  r2, =0xe000edc0                                    /* r2 = 0xe000edc0 [Location of MAIR0]. */\r
231         str  r4, [r2]                                                   /* Program MAIR0. */\r
232         ldr  r2, =0xe000ed98                                    /* r2 = 0xe000ed98 [Location of RNR]. */\r
233         adds r1, #4                                                             /* r1 = r1 + 4. r1 now points to first RBAR in TCB. */\r
234         movs r4, #4                                                             /* r4 = 4. */\r
235         str  r4, [r2]                                                   /* Program RNR = 4. */\r
236         ldmia r1!, {r5,r6}                                              /* Read first set of RBAR/RLAR from TCB. */\r
237         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
238         stmia r3!, {r5,r6}                                              /* Write first set of RBAR/RLAR registers. */\r
239         movs r4, #5                                                             /* r4 = 5. */\r
240         str  r4, [r2]                                                   /* Program RNR = 5. */\r
241         ldmia r1!, {r5,r6}                                              /* Read second set of RBAR/RLAR from TCB. */\r
242         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
243         stmia r3!, {r5,r6}                                              /* Write second set of RBAR/RLAR registers. */\r
244         movs r4, #6                                                             /* r4 = 6. */\r
245         str  r4, [r2]                                                   /* Program RNR = 6. */\r
246         ldmia r1!, {r5,r6}                                              /* Read third set of RBAR/RLAR from TCB. */\r
247         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
248         stmia r3!, {r5,r6}                                              /* Write third set of RBAR/RLAR registers. */\r
249         movs r4, #7                                                             /* r4 = 7. */\r
250         str  r4, [r2]                                                   /* Program RNR = 7. */\r
251         ldmia r1!, {r5,r6}                                              /* Read fourth set of RBAR/RLAR from TCB. */\r
252         ldr  r3, =0xe000ed9c                                    /* r3 = 0xe000ed9c [Location of RBAR]. */\r
253         stmia r3!, {r5,r6}                                              /* Write fourth set of RBAR/RLAR registers. */\r
254 \r
255         ldr r2, =0xe000ed94                                             /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */\r
256         ldr r3, [r2]                                                    /* Read the value of MPU_CTRL. */\r
257         movs r4, #1                                                             /* r4 = 1. */\r
258         orrs r3, r4                                                             /* r3 = r3 | r4 i.e. Set the bit 0 in r3. */\r
259         str r3, [r2]                                                    /* Enable MPU. */\r
260         dsb                                                                             /* Force memory writes before continuing. */\r
261 #endif /* configENABLE_MPU */\r
262 \r
263 #if ( configENABLE_MPU == 1 )\r
264         adds r0, r0, #28                                                /* Move to the high registers. */\r
265         ldmia r0!, {r4-r7}                                              /* Restore the high registers that are not automatically restored. */\r
266         mov r8, r4                                                              /* r8 = r4. */\r
267         mov r9, r5                                                              /* r9 = r5. */\r
268         mov r10, r6                                                             /* r10 = r6. */\r
269         mov r11, r7                                                             /* r11 = r7. */\r
270         msr psp, r0                                                             /* Remember the new top of stack for the task. */\r
271         subs r0, r0, #44                                                /* Move to the starting of the saved context. */\r
272         ldmia r0!, {r1-r7}                                              /* Read from stack - r1 = PSPLIM, r2 = CONTROL, r3 = LR and r4-r7 restored. */\r
273         msr psplim, r1                                                  /* Restore the PSPLIM register value for the task. */\r
274         msr control, r2                                                 /* Restore the CONTROL register value for the task. */\r
275         bx r3\r
276 #else /* configENABLE_MPU */\r
277         adds r0, r0, #24                                                /* Move to the high registers. */\r
278         ldmia r0!, {r4-r7}                                              /* Restore the high registers that are not automatically restored. */\r
279         mov r8, r4                                                              /* r8 = r4. */\r
280         mov r9, r5                                                              /* r9 = r5. */\r
281         mov r10, r6                                                             /* r10 = r6. */\r
282         mov r11, r7                                                             /* r11 = r7. */\r
283         msr psp, r0                                                             /* Remember the new top of stack for the task. */\r
284         subs r0, r0, #40                                                /* Move to the starting of the saved context. */\r
285         ldmia r0!, {r2-r7}                                              /* Read from stack - r2 = PSPLIM, r3 = LR and r4-r7 restored. */\r
286         msr psplim, r2                                                  /* Restore the PSPLIM register value for the task. */\r
287         bx r3\r
288 #endif /* configENABLE_MPU */\r
289 /*-----------------------------------------------------------*/\r
290 \r
291 SVC_Handler:\r
292         movs r0, #4\r
293         mov r1, lr\r
294         tst r0, r1\r
295         beq stacking_used_msp\r
296         mrs r0, psp\r
297         b vPortSVCHandler_C\r
298         stacking_used_msp:\r
299                 mrs r0, msp\r
300                 b vPortSVCHandler_C\r
301 /*-----------------------------------------------------------*/\r
302 \r
303         END\r