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/*
* FreeRTOS Kernel V10.3.0
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
EXTERN pxCurrentTCB
EXTERN vTaskSwitchContext
EXTERN vPortSVCHandler_C
PUBLIC xIsPrivileged
PUBLIC vResetPrivilege
PUBLIC vRestoreContextOfFirstTask
PUBLIC vRaisePrivilege
PUBLIC vStartFirstTask
PUBLIC ulSetInterruptMask
PUBLIC vClearInterruptMask
PUBLIC PendSV_Handler
PUBLIC SVC_Handler
#if ( configENABLE_FPU == 1 )
#error Cortex-M23 does not have a Floating Point Unit (FPU) and therefore configENABLE_FPU must be set to 0.
#endif
/*-----------------------------------------------------------*/
/*---------------- Unprivileged Functions -------------------*/
/*-----------------------------------------------------------*/
SECTION .text:CODE:NOROOT(2)
THUMB
/*-----------------------------------------------------------*/
xIsPrivileged:
mrs r0, control /* r0 = CONTROL. */
movs r1, #1 /* r1 = 1. */
tst r0, r1 /* Perform r0 & r1 (bitwise AND) and update the conditions flag. */
beq running_privileged /* If the result of previous AND operation was 0, branch. */
movs r0, #0 /* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */
bx lr /* Return. */
running_privileged:
movs r0, #1 /* CONTROL[0]==0. Return true to indicate that the processor is privileged. */
bx lr /* Return. */
/*-----------------------------------------------------------*/
vResetPrivilege:
mrs r0, control /* r0 = CONTROL. */
movs r1, #1 /* r1 = 1. */
orrs r0, r1 /* r0 = r0 | r1. */
msr control, r0 /* CONTROL = r0. */
bx lr /* Return to the caller. */
/*-----------------------------------------------------------*/
/*----------------- Privileged Functions --------------------*/
/*-----------------------------------------------------------*/
SECTION privileged_functions:CODE:NOROOT(2)
THUMB
/*-----------------------------------------------------------*/
vRestoreContextOfFirstTask:
ldr r2, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r2] /* Read pxCurrentTCB. */
ldr r0, [r1] /* Read top of stack from TCB - The first item in pxCurrentTCB is the task top of stack. */
#if ( configENABLE_MPU == 1 )
dmb /* Complete outstanding transfers before disabling MPU. */
ldr r2, =0xe000ed94 /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
movs r4, #1 /* r4 = 1. */
bics r3, r4 /* r3 = r3 & ~r4 i.e. Clear the bit 0 in r3. */
str r3, [r2] /* Disable MPU. */
adds r1, #4 /* r1 = r1 + 4. r1 now points to MAIR0 in TCB. */
ldr r4, [r1] /* r4 = *r1 i.e. r4 = MAIR0. */
ldr r2, =0xe000edc0 /* r2 = 0xe000edc0 [Location of MAIR0]. */
str r4, [r2] /* Program MAIR0. */
ldr r2, =0xe000ed98 /* r2 = 0xe000ed98 [Location of RNR]. */
adds r1, #4 /* r1 = r1 + 4. r1 now points to first RBAR in TCB. */
movs r4, #4 /* r4 = 4. */
str r4, [r2] /* Program RNR = 4. */
ldmia r1!, {r5,r6} /* Read first set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write first set of RBAR/RLAR registers. */
movs r4, #5 /* r4 = 5. */
str r4, [r2] /* Program RNR = 5. */
ldmia r1!, {r5,r6} /* Read second set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write second set of RBAR/RLAR registers. */
movs r4, #6 /* r4 = 6. */
str r4, [r2] /* Program RNR = 6. */
ldmia r1!, {r5,r6} /* Read third set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write third set of RBAR/RLAR registers. */
movs r4, #7 /* r4 = 7. */
str r4, [r2] /* Program RNR = 7. */
ldmia r1!, {r5,r6} /* Read fourth set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write fourth set of RBAR/RLAR registers. */
ldr r2, =0xe000ed94 /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
movs r4, #1 /* r4 = 1. */
orrs r3, r4 /* r3 = r3 | r4 i.e. Set the bit 0 in r3. */
str r3, [r2] /* Enable MPU. */
dsb /* Force memory writes before continuing. */
#endif /* configENABLE_MPU */
#if ( configENABLE_MPU == 1 )
ldm r0!, {r1-r3} /* Read from stack - r1 = PSPLIM, r2 = CONTROL and r3 = EXC_RETURN. */
msr psplim, r1 /* Set this task's PSPLIM value. */
msr control, r2 /* Set this task's CONTROL value. */
adds r0, #32 /* Discard everything up to r0. */
msr psp, r0 /* This is now the new top of stack to use in the task. */
isb
bx r3 /* Finally, branch to EXC_RETURN. */
#else /* configENABLE_MPU */
ldm r0!, {r1-r2} /* Read from stack - r1 = PSPLIM and r2 = EXC_RETURN. */
msr psplim, r1 /* Set this task's PSPLIM value. */
movs r1, #2 /* r1 = 2. */
msr CONTROL, r1 /* Switch to use PSP in the thread mode. */
adds r0, #32 /* Discard everything up to r0. */
msr psp, r0 /* This is now the new top of stack to use in the task. */
isb
bx r2 /* Finally, branch to EXC_RETURN. */
#endif /* configENABLE_MPU */
/*-----------------------------------------------------------*/
vRaisePrivilege:
mrs r0, control /* Read the CONTROL register. */
movs r1, #1 /* r1 = 1. */
bics r0, r1 /* Clear the bit 0. */
msr control, r0 /* Write back the new CONTROL value. */
bx lr /* Return to the caller. */
/*-----------------------------------------------------------*/
vStartFirstTask:
ldr r0, =0xe000ed08 /* Use the NVIC offset register to locate the stack. */
ldr r0, [r0] /* Read the VTOR register which gives the address of vector table. */
ldr r0, [r0] /* The first entry in vector table is stack pointer. */
msr msp, r0 /* Set the MSP back to the start of the stack. */
cpsie i /* Globally enable interrupts. */
dsb
isb
svc 2 /* System call to start the first task. portSVC_START_SCHEDULER = 2. */
nop
/*-----------------------------------------------------------*/
ulSetInterruptMask:
mrs r0, PRIMASK
cpsid i
bx lr
/*-----------------------------------------------------------*/
vClearInterruptMask:
msr PRIMASK, r0
bx lr
/*-----------------------------------------------------------*/
PendSV_Handler:
mrs r0, psp /* Read PSP in r0. */
ldr r2, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r2] /* Read pxCurrentTCB. */
#if ( configENABLE_MPU == 1 )
subs r0, r0, #44 /* Make space for PSPLIM, CONTROL, LR and the remaining registers on the stack. */
str r0, [r1] /* Save the new top of stack in TCB. */
mrs r1, psplim /* r1 = PSPLIM. */
mrs r2, control /* r2 = CONTROL. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r0!, {r1-r7} /* Store on the stack - PSPLIM, CONTROL, LR and low registers that are not automatically saved. */
mov r4, r8 /* r4 = r8. */
mov r5, r9 /* r5 = r9. */
mov r6, r10 /* r6 = r10. */
mov r7, r11 /* r7 = r11. */
stmia r0!, {r4-r7} /* Store the high registers that are not saved automatically. */
#else /* configENABLE_MPU */
subs r0, r0, #40 /* Make space for PSPLIM, LR and the remaining registers on the stack. */
str r0, [r1] /* Save the new top of stack in TCB. */
mrs r2, psplim /* r2 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r0!, {r2-r7} /* Store on the stack - PSPLIM, LR and low registers that are not automatically saved. */
mov r4, r8 /* r4 = r8. */
mov r5, r9 /* r5 = r9. */
mov r6, r10 /* r6 = r10. */
mov r7, r11 /* r7 = r11. */
stmia r0!, {r4-r7} /* Store the high registers that are not saved automatically. */
#endif /* configENABLE_MPU */
cpsid i
bl vTaskSwitchContext
cpsie i
ldr r2, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r2] /* Read pxCurrentTCB. */
ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. r0 now points to the top of stack. */
#if ( configENABLE_MPU == 1 )
dmb /* Complete outstanding transfers before disabling MPU. */
ldr r2, =0xe000ed94 /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
movs r4, #1 /* r4 = 1. */
bics r3, r4 /* r3 = r3 & ~r4 i.e. Clear the bit 0 in r3. */
str r3, [r2] /* Disable MPU. */
adds r1, #4 /* r1 = r1 + 4. r1 now points to MAIR0 in TCB. */
ldr r4, [r1] /* r4 = *r1 i.e. r4 = MAIR0. */
ldr r2, =0xe000edc0 /* r2 = 0xe000edc0 [Location of MAIR0]. */
str r4, [r2] /* Program MAIR0. */
ldr r2, =0xe000ed98 /* r2 = 0xe000ed98 [Location of RNR]. */
adds r1, #4 /* r1 = r1 + 4. r1 now points to first RBAR in TCB. */
movs r4, #4 /* r4 = 4. */
str r4, [r2] /* Program RNR = 4. */
ldmia r1!, {r5,r6} /* Read first set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write first set of RBAR/RLAR registers. */
movs r4, #5 /* r4 = 5. */
str r4, [r2] /* Program RNR = 5. */
ldmia r1!, {r5,r6} /* Read second set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write second set of RBAR/RLAR registers. */
movs r4, #6 /* r4 = 6. */
str r4, [r2] /* Program RNR = 6. */
ldmia r1!, {r5,r6} /* Read third set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write third set of RBAR/RLAR registers. */
movs r4, #7 /* r4 = 7. */
str r4, [r2] /* Program RNR = 7. */
ldmia r1!, {r5,r6} /* Read fourth set of RBAR/RLAR from TCB. */
ldr r3, =0xe000ed9c /* r3 = 0xe000ed9c [Location of RBAR]. */
stmia r3!, {r5,r6} /* Write fourth set of RBAR/RLAR registers. */
ldr r2, =0xe000ed94 /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
movs r4, #1 /* r4 = 1. */
orrs r3, r4 /* r3 = r3 | r4 i.e. Set the bit 0 in r3. */
str r3, [r2] /* Enable MPU. */
dsb /* Force memory writes before continuing. */
#endif /* configENABLE_MPU */
#if ( configENABLE_MPU == 1 )
adds r0, r0, #28 /* Move to the high registers. */
ldmia r0!, {r4-r7} /* Restore the high registers that are not automatically restored. */
mov r8, r4 /* r8 = r4. */
mov r9, r5 /* r9 = r5. */
mov r10, r6 /* r10 = r6. */
mov r11, r7 /* r11 = r7. */
msr psp, r0 /* Remember the new top of stack for the task. */
subs r0, r0, #44 /* Move to the starting of the saved context. */
ldmia r0!, {r1-r7} /* Read from stack - r1 = PSPLIM, r2 = CONTROL, r3 = LR and r4-r7 restored. */
msr psplim, r1 /* Restore the PSPLIM register value for the task. */
msr control, r2 /* Restore the CONTROL register value for the task. */
bx r3
#else /* configENABLE_MPU */
adds r0, r0, #24 /* Move to the high registers. */
ldmia r0!, {r4-r7} /* Restore the high registers that are not automatically restored. */
mov r8, r4 /* r8 = r4. */
mov r9, r5 /* r9 = r5. */
mov r10, r6 /* r10 = r6. */
mov r11, r7 /* r11 = r7. */
msr psp, r0 /* Remember the new top of stack for the task. */
subs r0, r0, #40 /* Move to the starting of the saved context. */
ldmia r0!, {r2-r7} /* Read from stack - r2 = PSPLIM, r3 = LR and r4-r7 restored. */
msr psplim, r2 /* Restore the PSPLIM register value for the task. */
bx r3
#endif /* configENABLE_MPU */
/*-----------------------------------------------------------*/
SVC_Handler:
movs r0, #4
mov r1, lr
tst r0, r1
beq stacking_used_msp
mrs r0, psp
b vPortSVCHandler_C
stacking_used_msp:
mrs r0, msp
b vPortSVCHandler_C
/*-----------------------------------------------------------*/
END
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