2 * FreeRTOS Kernel V10.2.1
\r
3 * Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
\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
12 * The above copyright notice and this permission notice shall be included in all
\r
13 * copies or substantial portions of the Software.
\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
22 * http://www.FreeRTOS.org
\r
23 * http://aws.amazon.com/freertos
\r
25 * 1 tab == 4 spaces!
\r
28 #include <FreeRTOSConfig.h>
\r
34 EXTERN vTaskSwitchContext
\r
35 EXTERN vPortSVCHandler_C
\r
37 PUBLIC xPortPendSVHandler
\r
38 PUBLIC vPortSVCHandler
\r
39 PUBLIC vPortStartFirstTask
\r
40 PUBLIC vPortEnableVFP
\r
41 PUBLIC vPortRestoreContextOfFirstTask
\r
42 PUBLIC xIsPrivileged
\r
43 PUBLIC vResetPrivilege
\r
45 /*-----------------------------------------------------------*/
\r
50 /* Get the location of the current TCB. */
\r
51 ldr r3, =pxCurrentTCB
\r
54 /* Is the task using the FPU context? If so, push high vfp registers. */
\r
57 vstmdbeq r0!, {s16-s31}
\r
59 /* Save the core registers. */
\r
61 stmdb r0!, {r1, r4-r11, r14}
\r
63 /* Save the new top of stack into the first member of the TCB. */
\r
67 mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
\r
71 bl vTaskSwitchContext
\r
76 /* The first item in pxCurrentTCB is the task top of stack. */
\r
79 /* Move onto the second item in the TCB... */
\r
82 dmb /* Complete outstanding transfers before disabling MPU. */
\r
83 ldr r2, =0xe000ed94 /* MPU_CTRL register. */
\r
84 ldr r3, [r2] /* Read the value of MPU_CTRL. */
\r
85 bic r3, r3, #1 /* r3 = r3 & ~1 i.e. Clear the bit 0 in r3. */
\r
86 str r3, [r2] /* Disable MPU. */
\r
88 /* Region Base Address register. */
\r
90 /* Read 4 sets of MPU registers. */
\r
92 /* Write 4 sets of MPU registers. */
\r
95 ldr r2, =0xe000ed94 /* MPU_CTRL register. */
\r
96 ldr r3, [r2] /* Read the value of MPU_CTRL. */
\r
97 orr r3, r3, #1 /* r3 = r3 | 1 i.e. Set the bit 0 in r3. */
\r
98 str r3, [r2] /* Enable MPU. */
\r
99 dsb /* Force memory writes before continuing. */
\r
101 /* Pop the registers that are not automatically saved on exception entry. */
\r
102 ldmia r0!, {r3-r11, r14}
\r
105 /* Is the task using the FPU context? If so, pop the high vfp registers
\r
109 vldmiaeq r0!, {s16-s31}
\r
117 /*-----------------------------------------------------------*/
\r
120 #ifndef USE_PROCESS_STACK /* Code should not be required if a main() is using the process stack. */
\r
128 b vPortSVCHandler_C
\r
130 /*-----------------------------------------------------------*/
\r
132 vPortStartFirstTask:
\r
133 /* Use the NVIC offset register to locate the stack. */
\r
134 ldr r0, =0xE000ED08
\r
137 /* Set the msp back to the start of the stack. */
\r
139 /* Clear the bit that indicates the FPU is in use in case the FPU was used
\r
140 before the scheduler was started - which would otherwise result in the
\r
141 unnecessary leaving of space in the SVC stack for lazy saving of FPU
\r
145 /* Call SVC to start the first task. */
\r
152 /*-----------------------------------------------------------*/
\r
154 vPortRestoreContextOfFirstTask:
\r
155 /* Use the NVIC offset register to locate the stack. */
\r
156 ldr r0, =0xE000ED08
\r
159 /* Set the msp back to the start of the stack. */
\r
161 /* Restore the context. */
\r
162 ldr r3, =pxCurrentTCB
\r
164 /* The first item in the TCB is the task top of stack. */
\r
166 /* Move onto the second item in the TCB... */
\r
169 dmb /* Complete outstanding transfers before disabling MPU. */
\r
170 ldr r2, =0xe000ed94 /* MPU_CTRL register. */
\r
171 ldr r3, [r2] /* Read the value of MPU_CTRL. */
\r
172 bic r3, r3, #1 /* r3 = r3 & ~1 i.e. Clear the bit 0 in r3. */
\r
173 str r3, [r2] /* Disable MPU. */
\r
175 /* Region Base Address register. */
\r
176 ldr r2, =0xe000ed9c
\r
177 /* Read 4 sets of MPU registers. */
\r
178 ldmia r1!, {r4-r11}
\r
179 /* Write 4 sets of MPU registers. */
\r
180 stmia r2!, {r4-r11}
\r
182 ldr r2, =0xe000ed94 /* MPU_CTRL register. */
\r
183 ldr r3, [r2] /* Read the value of MPU_CTRL. */
\r
184 orr r3, r3, #1 /* r3 = r3 | 1 i.e. Set the bit 0 in r3. */
\r
185 str r3, [r2] /* Enable MPU. */
\r
186 dsb /* Force memory writes before continuing. */
\r
188 /* Pop the registers that are not automatically saved on exception entry. */
\r
189 ldmia r0!, {r3-r11, r14}
\r
191 /* Restore the task stack pointer. */
\r
197 /*-----------------------------------------------------------*/
\r
200 /* The FPU enable bits are in the CPACR. */
\r
201 ldr.w r0, =0xE000ED88
\r
204 /* Enable CP10 and CP11 coprocessors, then save back. */
\r
205 orr r1, r1, #( 0xf << 20 )
\r
209 /*-----------------------------------------------------------*/
\r
212 mrs r0, control /* r0 = CONTROL. */
\r
213 tst r0, #1 /* Perform r0 & 1 (bitwise AND) and update the conditions flag. */
\r
215 movne r0, #0 /* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */
\r
216 moveq r0, #1 /* CONTROL[0]==0. Return true to indicate that the processor is privileged. */
\r
217 bx lr /* Return. */
\r
218 /*-----------------------------------------------------------*/
\r
221 mrs r0, control /* r0 = CONTROL. */
\r
222 orr r0, r0, #1 /* r0 = r0 | 1. */
\r
223 msr control, r0 /* CONTROL = r0. */
\r
224 bx lr /* Return to the caller. */
\r
225 /*-----------------------------------------------------------*/
\r