| /* |
| * FreeRTOS Kernel <DEVELOPMENT BRANCH> |
| * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| * |
| * SPDX-License-Identifier: MIT |
| * |
| * 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. |
| * |
| * https://www.FreeRTOS.org |
| * https://github.com/FreeRTOS |
| * |
| */ |
| |
| /* Including FreeRTOSConfig.h here will cause build errors if the header file |
| contains code not understood by the assembler - for example the 'extern' keyword. |
| To avoid errors place any such code inside a #ifdef __ICCARM__/#endif block so |
| the code is included in C files but excluded by the preprocessor in assembly |
| files (__ICCARM__ is defined by the IAR C compiler but not by the IAR assembler. */ |
| #include "FreeRTOSConfig.h" |
| |
| /* System call numbers includes. */ |
| #include "mpu_syscall_numbers.h" |
| |
| #ifndef configUSE_MPU_WRAPPERS_V1 |
| #define configUSE_MPU_WRAPPERS_V1 0 |
| #endif |
| |
| |
| EXTERN pxCurrentTCB |
| EXTERN xSecureContext |
| EXTERN vTaskSwitchContext |
| EXTERN vPortSVCHandler_C |
| EXTERN SecureContext_SaveContext |
| EXTERN SecureContext_LoadContext |
| #if ( ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) ) |
| EXTERN vSystemCallEnter |
| EXTERN vSystemCallExit |
| #endif |
| |
| PUBLIC xIsPrivileged |
| PUBLIC vResetPrivilege |
| PUBLIC vPortAllocateSecureContext |
| PUBLIC vRestoreContextOfFirstTask |
| PUBLIC vRaisePrivilege |
| PUBLIC vStartFirstTask |
| PUBLIC ulSetInterruptMask |
| PUBLIC vClearInterruptMask |
| PUBLIC PendSV_Handler |
| PUBLIC SVC_Handler |
| PUBLIC vPortFreeSecureContext |
| |
| #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. */ |
| /*-----------------------------------------------------------*/ |
| |
| vPortAllocateSecureContext: |
| svc 100 /* Secure context is allocated in the supervisor call. portSVC_ALLOCATE_SECURE_CONTEXT = 100. */ |
| bx lr /* Return. */ |
| /*-----------------------------------------------------------*/ |
| |
| /*----------------- Privileged Functions --------------------*/ |
| |
| /*-----------------------------------------------------------*/ |
| |
| SECTION privileged_functions:CODE:NOROOT(2) |
| THUMB |
| /*-----------------------------------------------------------*/ |
| |
| #if ( configENABLE_MPU == 1 ) |
| |
| vRestoreContextOfFirstTask: |
| program_mpu_first_task: |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r0, [r3] /* r0 = pxCurrentTCB.*/ |
| |
| dmb /* Complete outstanding transfers before disabling MPU. */ |
| ldr r1, =0xe000ed94 /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| ldr r2, [r1] /* Read the value of MPU_CTRL. */ |
| movs r3, #1 /* r3 = 1. */ |
| bics r2, r3 /* r2 = r2 & ~r3 i.e. Clear the bit 0 in r2. */ |
| str r2, [r1] /* Disable MPU. */ |
| |
| adds r0, #4 /* r0 = r0 + 4. r0 now points to MAIR0 in TCB. */ |
| ldr r1, [r0] /* r1 = *r0 i.e. r1 = MAIR0. */ |
| ldr r2, =0xe000edc0 /* r2 = 0xe000edc0 [Location of MAIR0]. */ |
| str r1, [r2] /* Program MAIR0. */ |
| |
| adds r0, #4 /* r0 = r0 + 4. r0 now points to first RBAR in TCB. */ |
| ldr r1, =0xe000ed98 /* r1 = 0xe000ed98 [Location of RNR]. */ |
| |
| movs r3, #4 /* r3 = 4. */ |
| str r3, [r1] /* Program RNR = 4. */ |
| ldmia r0!, {r4-r5} /* Read first set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write first set of RBAR/RLAR registers. */ |
| movs r3, #5 /* r3 = 5. */ |
| str r3, [r1] /* Program RNR = 5. */ |
| ldmia r0!, {r4-r5} /* Read second set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write second set of RBAR/RLAR registers. */ |
| movs r3, #6 /* r3 = 6. */ |
| str r3, [r1] /* Program RNR = 6. */ |
| ldmia r0!, {r4-r5} /* Read third set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write third set of RBAR/RLAR registers. */ |
| movs r3, #7 /* r3 = 6. */ |
| str r3, [r1] /* Program RNR = 7. */ |
| ldmia r0!, {r4-r5} /* Read fourth set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write fourth set of RBAR/RLAR registers. */ |
| |
| ldr r1, =0xe000ed94 /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| ldr r2, [r1] /* Read the value of MPU_CTRL. */ |
| movs r3, #1 /* r3 = 1. */ |
| orrs r2, r3 /* r2 = r2 | r3 i.e. Set the bit 0 in r2. */ |
| str r2, [r1] /* Enable MPU. */ |
| dsb /* Force memory writes before continuing. */ |
| |
| restore_context_first_task: |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* r1 = pxCurrentTCB.*/ |
| ldr r2, [r1] /* r2 = Location of saved context in TCB. */ |
| |
| restore_special_regs_first_task: |
| subs r2, #20 |
| ldmia r2!, {r0, r3-r6} /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, r6 = LR. */ |
| subs r2, #20 |
| msr psp, r3 |
| msr control, r5 |
| mov lr, r6 |
| ldr r4, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| str r0, [r4] /* Restore xSecureContext. */ |
| |
| restore_general_regs_first_task: |
| subs r2, #32 |
| ldmia r2!, {r4-r7} /* r4-r7 contain half of the hardware saved context. */ |
| stmia r3!, {r4-r7} /* Copy half of the the hardware saved context on the task stack. */ |
| ldmia r2!, {r4-r7} /* r4-r7 contain rest half of the hardware saved context. */ |
| stmia r3!, {r4-r7} /* Copy rest half of the the hardware saved context on the task stack. */ |
| subs r2, #48 |
| ldmia r2!, {r4-r7} /* Restore r8-r11. */ |
| mov r8, r4 /* r8 = r4. */ |
| mov r9, r5 /* r9 = r5. */ |
| mov r10, r6 /* r10 = r6. */ |
| mov r11, r7 /* r11 = r7. */ |
| subs r2, #32 |
| ldmia r2!, {r4-r7} /* Restore r4-r7. */ |
| subs r2, #16 |
| |
| restore_context_done_first_task: |
| str r2, [r1] /* Save the location where the context should be saved next as the first member of TCB. */ |
| bx lr |
| |
| #else /* configENABLE_MPU */ |
| |
| vRestoreContextOfFirstTask: |
| ldr r2, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r3, [r2] /* Read pxCurrentTCB. */ |
| ldr r0, [r3] /* Read top of stack from TCB - The first item in pxCurrentTCB is the task top of stack. */ |
| |
| ldm r0!, {r1-r3} /* Read from stack - r1 = xSecureContext, r2 = PSPLIM and r3 = EXC_RETURN. */ |
| ldr r4, =xSecureContext |
| str r1, [r4] /* Set xSecureContext to this task's value for the same. */ |
| 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 r3 /* 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 102 /* System call to start the first task. portSVC_START_SCHEDULER = 102. */ |
| /*-----------------------------------------------------------*/ |
| |
| ulSetInterruptMask: |
| mrs r0, PRIMASK |
| cpsid i |
| bx lr |
| /*-----------------------------------------------------------*/ |
| |
| vClearInterruptMask: |
| msr PRIMASK, r0 |
| bx lr |
| /*-----------------------------------------------------------*/ |
| #if ( configENABLE_MPU == 1 ) |
| |
| PendSV_Handler: |
| ldr r3, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| ldr r0, [r3] /* Read xSecureContext - Value of xSecureContext must be in r0 as it is used as a parameter later. */ |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* Read pxCurrentTCB - Value of pxCurrentTCB must be in r1 as it is used as a parameter later.*/ |
| ldr r2, [r1] /* r2 = Location in TCB where the context should be saved. */ |
| |
| cbz r0, save_ns_context /* No secure context to save. */ |
| save_s_context: |
| push {r0-r2, lr} |
| bl SecureContext_SaveContext /* Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| pop {r0-r3} /* LR is now in r3. */ |
| mov lr, r3 /* Restore LR. */ |
| |
| save_ns_context: |
| mov r3, lr /* r3 = LR (EXC_RETURN). */ |
| lsls r3, r3, #25 /* r3 = 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. */ |
| bmi save_special_regs /* r3 < 0 ==> Bit[6] in EXC_RETURN is 1 ==> secure stack was used to store the stack frame. */ |
| |
| save_general_regs: |
| mrs r3, psp |
| stmia r2!, {r4-r7} /* Store r4-r7. */ |
| mov r4, r8 /* r4 = r8. */ |
| mov r5, r9 /* r5 = r9. */ |
| mov r6, r10 /* r6 = r10. */ |
| mov r7, r11 /* r7 = r11. */ |
| stmia r2!, {r4-r7} /* Store r8-r11. */ |
| ldmia r3!, {r4-r7} /* Copy half of the hardware saved context into r4-r7. */ |
| stmia r2!, {r4-r7} /* Store the hardware saved context. */ |
| ldmia r3!, {r4-r7} /* Copy rest half of the hardware saved context into r4-r7. */ |
| stmia r2!, {r4-r7} /* Store the hardware saved context. */ |
| |
| save_special_regs: |
| mrs r3, psp /* r3 = PSP. */ |
| movs r4, #0 /* r4 = 0. 0 is stored in the PSPLIM slot. */ |
| mrs r5, control /* r5 = CONTROL. */ |
| mov r6, lr /* r6 = LR. */ |
| stmia r2!, {r0, r3-r6} /* Store xSecureContext, original PSP (after hardware has saved context), PSPLIM, CONTROL and LR. */ |
| str r2, [r1] /* Save the location from where the context should be restored as the first member of TCB. */ |
| |
| select_next_task: |
| cpsid i |
| bl vTaskSwitchContext |
| cpsie i |
| |
| program_mpu: |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r0, [r3] /* r0 = pxCurrentTCB.*/ |
| |
| dmb /* Complete outstanding transfers before disabling MPU. */ |
| ldr r1, =0xe000ed94 /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| ldr r2, [r1] /* Read the value of MPU_CTRL. */ |
| movs r3, #1 /* r3 = 1. */ |
| bics r2, r3 /* r2 = r2 & ~r3 i.e. Clear the bit 0 in r2. */ |
| str r2, [r1] /* Disable MPU. */ |
| |
| adds r0, #4 /* r0 = r0 + 4. r0 now points to MAIR0 in TCB. */ |
| ldr r1, [r0] /* r1 = *r0 i.e. r1 = MAIR0. */ |
| ldr r2, =0xe000edc0 /* r2 = 0xe000edc0 [Location of MAIR0]. */ |
| str r1, [r2] /* Program MAIR0. */ |
| |
| adds r0, #4 /* r0 = r0 + 4. r0 now points to first RBAR in TCB. */ |
| ldr r1, =0xe000ed98 /* r1 = 0xe000ed98 [Location of RNR]. */ |
| |
| movs r3, #4 /* r3 = 4. */ |
| str r3, [r1] /* Program RNR = 4. */ |
| ldmia r0!, {r4-r5} /* Read first set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write first set of RBAR/RLAR registers. */ |
| movs r3, #5 /* r3 = 5. */ |
| str r3, [r1] /* Program RNR = 5. */ |
| ldmia r0!, {r4-r5} /* Read second set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write second set of RBAR/RLAR registers. */ |
| movs r3, #6 /* r3 = 6. */ |
| str r3, [r1] /* Program RNR = 6. */ |
| ldmia r0!, {r4-r5} /* Read third set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write third set of RBAR/RLAR registers. */ |
| movs r3, #7 /* r3 = 6. */ |
| str r3, [r1] /* Program RNR = 7. */ |
| ldmia r0!, {r4-r5} /* Read fourth set of RBAR/RLAR registers from TCB. */ |
| ldr r2, =0xe000ed9c /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| stmia r2!, {r4-r5} /* Write fourth set of RBAR/RLAR registers. */ |
| |
| ldr r1, =0xe000ed94 /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| ldr r2, [r1] /* Read the value of MPU_CTRL. */ |
| movs r3, #1 /* r3 = 1. */ |
| orrs r2, r3 /* r2 = r2 | r3 i.e. Set the bit 0 in r2. */ |
| str r2, [r1] /* Enable MPU. */ |
| dsb /* Force memory writes before continuing. */ |
| |
| restore_context: |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* r1 = pxCurrentTCB.*/ |
| ldr r2, [r1] /* r2 = Location of saved context in TCB. */ |
| |
| restore_special_regs: |
| subs r2, #20 |
| ldmia r2!, {r0, r3-r6} /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, r6 = LR. */ |
| subs r2, #20 |
| msr psp, r3 |
| msr control, r5 |
| mov lr, r6 |
| ldr r4, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| str r0, [r4] /* Restore xSecureContext. */ |
| cbz r0, restore_ns_context /* No secure context to restore. */ |
| |
| restore_s_context: |
| push {r1-r3, lr} |
| bl SecureContext_LoadContext /* Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| pop {r1-r4} /* LR is now in r4. */ |
| mov lr, r4 |
| |
| restore_ns_context: |
| mov r0, lr /* r0 = LR (EXC_RETURN). */ |
| lsls r0, r0, #25 /* r0 = r0 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */ |
| bmi restore_context_done /* r0 < 0 ==> Bit[6] in EXC_RETURN is 1 ==> secure stack was used to store the stack frame. */ |
| |
| restore_general_regs: |
| subs r2, #32 |
| ldmia r2!, {r4-r7} /* r4-r7 contain half of the hardware saved context. */ |
| stmia r3!, {r4-r7} /* Copy half of the the hardware saved context on the task stack. */ |
| ldmia r2!, {r4-r7} /* r4-r7 contain rest half of the hardware saved context. */ |
| stmia r3!, {r4-r7} /* Copy rest half of the the hardware saved context on the task stack. */ |
| subs r2, #48 |
| ldmia r2!, {r4-r7} /* Restore r8-r11. */ |
| mov r8, r4 /* r8 = r4. */ |
| mov r9, r5 /* r9 = r5. */ |
| mov r10, r6 /* r10 = r6. */ |
| mov r11, r7 /* r11 = r7. */ |
| subs r2, #32 |
| ldmia r2!, {r4-r7} /* Restore r4-r7. */ |
| subs r2, #16 |
| |
| restore_context_done: |
| str r2, [r1] /* Save the location where the context should be saved next as the first member of TCB. */ |
| bx lr |
| |
| #else /* configENABLE_MPU */ |
| |
| PendSV_Handler: |
| ldr r3, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| ldr r0, [r3] /* Read xSecureContext - Value of xSecureContext must be in r0 as it is used as a parameter later. */ |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* Read pxCurrentTCB - Value of pxCurrentTCB must be in r1 as it is used as a parameter later. */ |
| mrs r2, psp /* Read PSP in r2. */ |
| |
| cbz r0, save_ns_context /* No secure context to save. */ |
| push {r0-r2, r14} |
| bl SecureContext_SaveContext /* Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| pop {r0-r3} /* LR is now in r3. */ |
| mov lr, r3 /* LR = r3. */ |
| lsls r1, r3, #25 /* r1 = 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. */ |
| bpl save_ns_context /* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */ |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* Read pxCurrentTCB. */ |
| |
| subs r2, r2, #12 /* Make space for xSecureContext, PSPLIM and LR on the stack. */ |
| str r2, [r1] /* Save the new top of stack in TCB. */ |
| movs r1, #0 /* r1 = 0. 0 is stored in the PSPLIM slot. */ |
| mov r3, lr /* r3 = LR/EXC_RETURN. */ |
| stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */ |
| |
| b select_next_task |
| |
| save_ns_context: |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* Read pxCurrentTCB. */ |
| subs r2, r2, #44 /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */ |
| str r2, [r1] /* Save the new top of stack in TCB. */ |
| movs r1, #0 /* r1 = 0. 0 is stored in the PSPLIM slot. */ |
| mov r3, lr /* r3 = LR/EXC_RETURN. */ |
| stmia r2!, {r0, r1, r3-r7} /* Store xSecureContext, PSPLIM, LR and the low registers that are not saved automatically. */ |
| mov r4, r8 /* r4 = r8. */ |
| mov r5, r9 /* r5 = r9. */ |
| mov r6, r10 /* r6 = r10. */ |
| mov r7, r11 /* r7 = r11. */ |
| stmia r2!, {r4-r7} /* Store the high registers that are not saved automatically. */ |
| |
| select_next_task: |
| cpsid i |
| bl vTaskSwitchContext |
| cpsie i |
| |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* Read pxCurrentTCB. */ |
| ldr r2, [r1] /* The first item in pxCurrentTCB is the task top of stack. r2 now points to the top of stack. */ |
| |
| ldmia r2!, {r0, r1, r4} /* Read from stack - r0 = xSecureContext, r1 = PSPLIM and r4 = LR. */ |
| mov lr, r4 /* LR = r4. */ |
| ldr r3, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| str r0, [r3] /* Restore the task's xSecureContext. */ |
| cbz r0, restore_ns_context /* If there is no secure context for the task, restore the non-secure context. */ |
| ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| ldr r1, [r3] /* Read pxCurrentTCB. */ |
| push {r2, r4} |
| bl SecureContext_LoadContext /* Restore the secure context. Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| pop {r2, r4} |
| mov lr, r4 /* LR = r4. */ |
| lsls r1, r4, #25 /* r1 = 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. */ |
| bpl restore_ns_context /* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */ |
| msr psp, r2 /* Remember the new top of stack for the task. */ |
| bx lr |
| |
| restore_ns_context: |
| adds r2, r2, #16 /* Move to the high registers. */ |
| ldmia r2!, {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, r2 /* Remember the new top of stack for the task. */ |
| subs r2, r2, #32 /* Go back to the low registers. */ |
| ldmia r2!, {r4-r7} /* Restore the low registers that are not automatically restored. */ |
| bx lr |
| |
| #endif /* configENABLE_MPU */ |
| /*-----------------------------------------------------------*/ |
| |
| #if ( ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) ) |
| |
| SVC_Handler: |
| movs r0, #4 |
| mov r1, lr |
| tst r0, r1 |
| beq stack_on_msp |
| stack_on_psp: |
| mrs r0, psp |
| b route_svc |
| stack_on_msp: |
| mrs r0, msp |
| b route_svc |
| |
| route_svc: |
| ldr r3, [r0, #24] |
| subs r3, #2 |
| ldrb r2, [r3, #0] |
| cmp r2, #NUM_SYSTEM_CALLS |
| blt system_call_enter |
| cmp r2, #104 /* portSVC_SYSTEM_CALL_EXIT. */ |
| beq system_call_exit |
| b vPortSVCHandler_C |
| |
| system_call_enter: |
| b vSystemCallEnter |
| system_call_exit: |
| b vSystemCallExit |
| |
| #else /* ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) */ |
| |
| 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 |
| |
| #endif /* ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) */ |
| /*-----------------------------------------------------------*/ |
| |
| vPortFreeSecureContext: |
| ldr r2, [r0] /* The first item in the TCB is the top of the stack. */ |
| ldr r1, [r2] /* The first item on the stack is the task's xSecureContext. */ |
| cmp r1, #0 /* Raise svc if task's xSecureContext is not NULL. */ |
| bne free_secure_context /* Branch if r1 != 0. */ |
| bx lr /* There is no secure context (xSecureContext is NULL). */ |
| free_secure_context: |
| svc 101 /* Secure context is freed in the supervisor call. portSVC_FREE_SECURE_CONTEXT = 101. */ |
| bx lr /* Return. */ |
| /*-----------------------------------------------------------*/ |
| |
| END |
