| /* |
| * FreeRTOS Kernel <DEVELOPMENT BRANCH> |
| * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| * Copyright 2024 Arm Limited and/or its affiliates |
| * <open-source-office@arm.com> |
| * |
| * 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 |
| * |
| */ |
| |
| /* Standard includes. */ |
| #include <stdint.h> |
| |
| /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE ensures that PRIVILEGED_FUNCTION |
| * is defined correctly and privileged functions are placed in correct sections. */ |
| #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE |
| |
| /* Portasm includes. */ |
| #include "portasm.h" |
| |
| /* System call numbers includes. */ |
| #include "mpu_syscall_numbers.h" |
| |
| /* MPU_WRAPPERS_INCLUDED_FROM_API_FILE is needed to be defined only for the |
| * header files. */ |
| #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE |
| |
| #if ( configENABLE_MPU == 1 ) |
| |
| void vRestoreContextOfFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " program_mpu_first_task: \n" |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r0, [r3] \n" /* r0 = pxCurrentTCB. */ |
| " \n" |
| " dmb \n" /* Complete outstanding transfers before disabling MPU. */ |
| " ldr r1, =0xe000ed94 \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| " ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */ |
| " bic r2, #1 \n" /* r2 = r2 & ~1 i.e. Clear the bit 0 in r2. */ |
| " str r2, [r1] \n" /* Disable MPU. */ |
| " \n" |
| " adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to MAIR0 in TCB. */ |
| " ldr r1, [r0] \n" /* r1 = *r0 i.e. r1 = MAIR0. */ |
| " ldr r2, =0xe000edc0 \n" /* r2 = 0xe000edc0 [Location of MAIR0]. */ |
| " str r1, [r2] \n" /* Program MAIR0. */ |
| " \n" |
| " adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to first RBAR in TCB. */ |
| " ldr r1, =0xe000ed98 \n" /* r1 = 0xe000ed98 [Location of RNR]. */ |
| " ldr r2, =0xe000ed9c \n" /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| " \n" |
| " movs r3, #4 \n" /* r3 = 4. */ |
| " str r3, [r1] \n" /* Program RNR = 4. */ |
| " ldmia r0!, {r4-r11} \n" /* Read 4 set of RBAR/RLAR registers from TCB. */ |
| " stmia r2, {r4-r11} \n" /* Write 4 set of RBAR/RLAR registers using alias registers. */ |
| " \n" |
| #if ( configTOTAL_MPU_REGIONS == 16 ) |
| " movs r3, #8 \n" /* r3 = 8. */ |
| " str r3, [r1] \n" /* Program RNR = 8. */ |
| " ldmia r0!, {r4-r11} \n" /* Read 4 set of RBAR/RLAR registers from TCB. */ |
| " stmia r2, {r4-r11} \n" /* Write 4 set of RBAR/RLAR registers using alias registers. */ |
| " movs r3, #12 \n" /* r3 = 12. */ |
| " str r3, [r1] \n" /* Program RNR = 12. */ |
| " ldmia r0!, {r4-r11} \n" /* Read 4 set of RBAR/RLAR registers from TCB. */ |
| " stmia r2, {r4-r11} \n" /* Write 4 set of RBAR/RLAR registers using alias registers. */ |
| #endif /* configTOTAL_MPU_REGIONS == 16 */ |
| " \n" |
| " ldr r1, =0xe000ed94 \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| " ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */ |
| " orr r2, #1 \n" /* r2 = r1 | 1 i.e. Set the bit 0 in r2. */ |
| " str r2, [r1] \n" /* Enable MPU. */ |
| " dsb \n" /* Force memory writes before continuing. */ |
| " \n" |
| " restore_context_first_task: \n" |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* r1 = pxCurrentTCB.*/ |
| " ldr r2, [r1] \n" /* r2 = Location of saved context in TCB. */ |
| " \n" |
| " restore_special_regs_first_task: \n" |
| " ldmdb r2!, {r0, r3-r5, lr} \n" /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, LR restored. */ |
| " msr psp, r3 \n" |
| " msr psplim, r4 \n" |
| " msr control, r5 \n" |
| " ldr r4, =xSecureContext \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| " str r0, [r4] \n" /* Restore xSecureContext. */ |
| " \n" |
| " restore_general_regs_first_task: \n" |
| " ldmdb r2!, {r4-r11} \n" /* r4-r11 contain hardware saved context. */ |
| " stmia r3!, {r4-r11} \n" /* Copy the hardware saved context on the task stack. */ |
| " ldmdb r2!, {r4-r11} \n" /* r4-r11 restored. */ |
| " \n" |
| " restore_context_done_first_task: \n" |
| " str r2, [r1] \n" /* Save the location where the context should be saved next as the first member of TCB. */ |
| " mov r0, #0 \n" |
| " msr basepri, r0 \n" /* Ensure that interrupts are enabled when the first task starts. */ |
| " bx lr \n" |
| ); |
| } |
| |
| #else /* configENABLE_MPU */ |
| |
| void vRestoreContextOfFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " ldr r2, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r3, [r2] \n" /* Read pxCurrentTCB. */ |
| " ldr r0, [r3] \n" /* Read top of stack from TCB - The first item in pxCurrentTCB is the task top of stack. */ |
| " \n" |
| " ldm r0!, {r1-r3} \n" /* Read from stack - r1 = xSecureContext, r2 = PSPLIM and r3 = EXC_RETURN. */ |
| " ldr r4, =xSecureContext \n" |
| " str r1, [r4] \n" /* Set xSecureContext to this task's value for the same. */ |
| " msr psplim, r2 \n" /* Set this task's PSPLIM value. */ |
| " mrs r1, control \n" /* Obtain current control register value. */ |
| " orrs r1, r1, #2 \n" /* r1 = r1 | 0x2 - Set the second bit to use the program stack pointer (PSP). */ |
| " msr control, r1 \n" /* Write back the new control register value. */ |
| " adds r0, #32 \n" /* Discard everything up to r0. */ |
| " msr psp, r0 \n" /* This is now the new top of stack to use in the task. */ |
| " isb \n" |
| " mov r0, #0 \n" |
| " msr basepri, r0 \n" /* Ensure that interrupts are enabled when the first task starts. */ |
| " bx r3 \n" /* Finally, branch to EXC_RETURN. */ |
| ); |
| } |
| |
| #endif /* configENABLE_MPU */ |
| /*-----------------------------------------------------------*/ |
| |
| BaseType_t xIsPrivileged( void ) /* __attribute__ (( naked )) */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " mrs r0, control \n" /* r0 = CONTROL. */ |
| " tst r0, #1 \n" /* Perform r0 & 1 (bitwise AND) and update the conditions flag. */ |
| " ite ne \n" |
| " movne r0, #0 \n" /* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */ |
| " moveq r0, #1 \n" /* CONTROL[0]==0. Return true to indicate that the processor is privileged. */ |
| " bx lr \n" /* Return. */ |
| ::: "r0", "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| void vRaisePrivilege( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " mrs r0, control \n" /* Read the CONTROL register. */ |
| " bic r0, #1 \n" /* Clear the bit 0. */ |
| " msr control, r0 \n" /* Write back the new CONTROL value. */ |
| " bx lr \n" /* Return to the caller. */ |
| ::: "r0", "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| void vResetPrivilege( void ) /* __attribute__ (( naked )) */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " mrs r0, control \n" /* r0 = CONTROL. */ |
| " orr r0, #1 \n" /* r0 = r0 | 1. */ |
| " msr control, r0 \n" /* CONTROL = r0. */ |
| " bx lr \n" /* Return to the caller. */ |
| ::: "r0", "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| void vStartFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " ldr r0, =0xe000ed08 \n" /* Use the NVIC offset register to locate the stack. */ |
| " ldr r0, [r0] \n" /* Read the VTOR register which gives the address of vector table. */ |
| " ldr r0, [r0] \n" /* The first entry in vector table is stack pointer. */ |
| " msr msp, r0 \n" /* Set the MSP back to the start of the stack. */ |
| " cpsie i \n" /* Globally enable interrupts. */ |
| " cpsie f \n" |
| " dsb \n" |
| " isb \n" |
| " svc %0 \n" /* System call to start the first task. */ |
| " nop \n" |
| ::"i" ( portSVC_START_SCHEDULER ) : "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| uint32_t ulSetInterruptMask( void ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " mrs r0, basepri \n" /* r0 = basepri. Return original basepri value. */ |
| " mov r1, %0 \n" /* r1 = configMAX_SYSCALL_INTERRUPT_PRIORITY. */ |
| " msr basepri, r1 \n" /* Disable interrupts up to configMAX_SYSCALL_INTERRUPT_PRIORITY. */ |
| " dsb \n" |
| " isb \n" |
| " bx lr \n" /* Return. */ |
| ::"i" ( configMAX_SYSCALL_INTERRUPT_PRIORITY ) : "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " msr basepri, r0 \n" /* basepri = ulMask. */ |
| " dsb \n" |
| " isb \n" |
| " bx lr \n" /* Return. */ |
| ::: "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| #if ( configENABLE_MPU == 1 ) |
| |
| void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " .extern SecureContext_SaveContext \n" |
| " .extern SecureContext_LoadContext \n" |
| " \n" |
| " ldr r3, =xSecureContext \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| " ldr r0, [r3] \n" /* Read xSecureContext - Value of xSecureContext must be in r0 as it is used as a parameter later. */ |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* Read pxCurrentTCB - Value of pxCurrentTCB must be in r1 as it is used as a parameter later. */ |
| " ldr r2, [r1] \n" /* r2 = Location in TCB where the context should be saved. */ |
| " \n" |
| " cbz r0, save_ns_context \n" /* No secure context to save. */ |
| " save_s_context: \n" |
| " push {r0-r2, lr} \n" |
| " bl SecureContext_SaveContext \n" /* Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| " pop {r0-r2, lr} \n" |
| " \n" |
| " save_ns_context: \n" |
| " mov r3, lr \n" /* r3 = LR (EXC_RETURN). */ |
| " lsls r3, r3, #25 \n" /* 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 \n" /* r3 < 0 ==> Bit[6] in EXC_RETURN is 1 ==> secure stack was used to store the stack frame. */ |
| " \n" |
| " save_general_regs: \n" |
| " mrs r3, psp \n" |
| " \n" |
| #if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) ) |
| " add r3, r3, #0x20 \n" /* Move r3 to location where s0 is saved. */ |
| " tst lr, #0x10 \n" |
| " ittt eq \n" |
| " vstmiaeq r2!, {s16-s31} \n" /* Store s16-s31. */ |
| " vldmiaeq r3, {s0-s16} \n" /* Copy hardware saved FP context into s0-s16. */ |
| " vstmiaeq r2!, {s0-s16} \n" /* Store hardware saved FP context. */ |
| " sub r3, r3, #0x20 \n" /* Set r3 back to the location of hardware saved context. */ |
| #endif /* configENABLE_FPU || configENABLE_MVE */ |
| " \n" |
| " stmia r2!, {r4-r11} \n" /* Store r4-r11. */ |
| " ldmia r3, {r4-r11} \n" /* Copy the hardware saved context into r4-r11. */ |
| " stmia r2!, {r4-r11} \n" /* Store the hardware saved context. */ |
| " \n" |
| " save_special_regs: \n" |
| " mrs r3, psp \n" /* r3 = PSP. */ |
| " mrs r4, psplim \n" /* r4 = PSPLIM. */ |
| " mrs r5, control \n" /* r5 = CONTROL. */ |
| " stmia r2!, {r0, r3-r5, lr} \n" /* Store xSecureContext, original PSP (after hardware has saved context), PSPLIM, CONTROL and LR. */ |
| " str r2, [r1] \n" /* Save the location from where the context should be restored as the first member of TCB. */ |
| " \n" |
| " select_next_task: \n" |
| " mov r0, %0 \n" /* r0 = configMAX_SYSCALL_INTERRUPT_PRIORITY */ |
| " msr basepri, r0 \n" /* Disable interrupts up to configMAX_SYSCALL_INTERRUPT_PRIORITY. */ |
| " dsb \n" |
| " isb \n" |
| " bl vTaskSwitchContext \n" |
| " mov r0, #0 \n" /* r0 = 0. */ |
| " msr basepri, r0 \n" /* Enable interrupts. */ |
| " \n" |
| " program_mpu: \n" |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r0, [r3] \n" /* r0 = pxCurrentTCB.*/ |
| " \n" |
| " dmb \n" /* Complete outstanding transfers before disabling MPU. */ |
| " ldr r1, =0xe000ed94 \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| " ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */ |
| " bic r2, #1 \n" /* r2 = r2 & ~1 i.e. Clear the bit 0 in r2. */ |
| " str r2, [r1] \n" /* Disable MPU. */ |
| " \n" |
| " adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to MAIR0 in TCB. */ |
| " ldr r1, [r0] \n" /* r1 = *r0 i.e. r1 = MAIR0. */ |
| " ldr r2, =0xe000edc0 \n" /* r2 = 0xe000edc0 [Location of MAIR0]. */ |
| " str r1, [r2] \n" /* Program MAIR0. */ |
| " \n" |
| " adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to first RBAR in TCB. */ |
| " ldr r1, =0xe000ed98 \n" /* r1 = 0xe000ed98 [Location of RNR]. */ |
| " ldr r2, =0xe000ed9c \n" /* r2 = 0xe000ed9c [Location of RBAR]. */ |
| " \n" |
| " movs r3, #4 \n" /* r3 = 4. */ |
| " str r3, [r1] \n" /* Program RNR = 4. */ |
| " ldmia r0!, {r4-r11} \n" /* Read 4 sets of RBAR/RLAR registers from TCB. */ |
| " stmia r2, {r4-r11} \n" /* Write 4 set of RBAR/RLAR registers using alias registers. */ |
| " \n" |
| #if ( configTOTAL_MPU_REGIONS == 16 ) |
| " movs r3, #8 \n" /* r3 = 8. */ |
| " str r3, [r1] \n" /* Program RNR = 8. */ |
| " ldmia r0!, {r4-r11} \n" /* Read 4 sets of RBAR/RLAR registers from TCB. */ |
| " stmia r2, {r4-r11} \n" /* Write 4 set of RBAR/RLAR registers using alias registers. */ |
| " movs r3, #12 \n" /* r3 = 12. */ |
| " str r3, [r1] \n" /* Program RNR = 12. */ |
| " ldmia r0!, {r4-r11} \n" /* Read 4 sets of RBAR/RLAR registers from TCB. */ |
| " stmia r2, {r4-r11} \n" /* Write 4 set of RBAR/RLAR registers using alias registers. */ |
| #endif /* configTOTAL_MPU_REGIONS == 16 */ |
| " \n" |
| " ldr r1, =0xe000ed94 \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */ |
| " ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */ |
| " orr r2, #1 \n" /* r2 = r2 | 1 i.e. Set the bit 0 in r2. */ |
| " str r2, [r1] \n" /* Enable MPU. */ |
| " dsb \n" /* Force memory writes before continuing. */ |
| " \n" |
| " restore_context: \n" |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* r1 = pxCurrentTCB.*/ |
| " ldr r2, [r1] \n" /* r2 = Location of saved context in TCB. */ |
| " \n" |
| " restore_special_regs: \n" |
| " ldmdb r2!, {r0, r3-r5, lr} \n" /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, LR restored. */ |
| " msr psp, r3 \n" |
| " msr psplim, r4 \n" |
| " msr control, r5 \n" |
| " ldr r4, =xSecureContext \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| " str r0, [r4] \n" /* Restore xSecureContext. */ |
| " cbz r0, restore_ns_context \n" /* No secure context to restore. */ |
| " \n" |
| " restore_s_context: \n" |
| " push {r1-r3, lr} \n" |
| " bl SecureContext_LoadContext \n" /* Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| " pop {r1-r3, lr} \n" |
| " \n" |
| " restore_ns_context: \n" |
| " mov r0, lr \n" /* r0 = LR (EXC_RETURN). */ |
| " lsls r0, r0, #25 \n" /* 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 \n" /* r0 < 0 ==> Bit[6] in EXC_RETURN is 1 ==> secure stack was used to store the stack frame. */ |
| " \n" |
| " restore_general_regs: \n" |
| " ldmdb r2!, {r4-r11} \n" /* r4-r11 contain hardware saved context. */ |
| " stmia r3!, {r4-r11} \n" /* Copy the hardware saved context on the task stack. */ |
| " ldmdb r2!, {r4-r11} \n" /* r4-r11 restored. */ |
| #if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) ) |
| " tst lr, #0x10 \n" |
| " ittt eq \n" |
| " vldmdbeq r2!, {s0-s16} \n" /* s0-s16 contain hardware saved FP context. */ |
| " vstmiaeq r3!, {s0-s16} \n" /* Copy hardware saved FP context on the task stack. */ |
| " vldmdbeq r2!, {s16-s31} \n" /* Restore s16-s31. */ |
| #endif /* configENABLE_FPU || configENABLE_MVE */ |
| " \n" |
| " restore_context_done: \n" |
| " str r2, [r1] \n" /* Save the location where the context should be saved next as the first member of TCB. */ |
| " bx lr \n" |
| ::"i" ( configMAX_SYSCALL_INTERRUPT_PRIORITY ) |
| ); |
| } |
| |
| #else /* configENABLE_MPU */ |
| |
| void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " .extern SecureContext_SaveContext \n" |
| " .extern SecureContext_LoadContext \n" |
| " \n" |
| " ldr r3, =xSecureContext \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| " ldr r0, [r3] \n" /* Read xSecureContext - Value of xSecureContext must be in r0 as it is used as a parameter later. */ |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* Read pxCurrentTCB - Value of pxCurrentTCB must be in r1 as it is used as a parameter later. */ |
| " mrs r2, psp \n" /* Read PSP in r2. */ |
| " \n" |
| " cbz r0, save_ns_context \n" /* No secure context to save. */ |
| " push {r0-r2, r14} \n" |
| " bl SecureContext_SaveContext \n" /* Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| " pop {r0-r3} \n" /* LR is now in r3. */ |
| " mov lr, r3 \n" /* LR = r3. */ |
| " lsls r1, r3, #25 \n" /* 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 \n" /* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */ |
| " \n" |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* Read pxCurrentTCB.*/ |
| " subs r2, r2, #12 \n" /* Make space for xSecureContext, PSPLIM and LR on the stack. */ |
| " str r2, [r1] \n" /* Save the new top of stack in TCB. */ |
| " mrs r1, psplim \n" /* r1 = PSPLIM. */ |
| " mov r3, lr \n" /* r3 = LR/EXC_RETURN. */ |
| " stmia r2!, {r0, r1, r3} \n" /* Store xSecureContext, PSPLIM and LR on the stack. */ |
| " b select_next_task \n" |
| " \n" |
| " save_ns_context: \n" |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* Read pxCurrentTCB. */ |
| #if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) ) |
| " tst lr, #0x10 \n" /* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the Extended Stack Frame is in use. */ |
| " it eq \n" |
| " vstmdbeq r2!, {s16-s31} \n" /* Store the additional FP context registers which are not saved automatically. */ |
| #endif /* configENABLE_FPU || configENABLE_MVE */ |
| " subs r2, r2, #44 \n" /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */ |
| " str r2, [r1] \n" /* Save the new top of stack in TCB. */ |
| " adds r2, r2, #12 \n" /* r2 = r2 + 12. */ |
| " stm r2, {r4-r11} \n" /* Store the registers that are not saved automatically. */ |
| " mrs r1, psplim \n" /* r1 = PSPLIM. */ |
| " mov r3, lr \n" /* r3 = LR/EXC_RETURN. */ |
| " subs r2, r2, #12 \n" /* r2 = r2 - 12. */ |
| " stmia r2!, {r0, r1, r3} \n" /* Store xSecureContext, PSPLIM and LR on the stack. */ |
| " \n" |
| " select_next_task: \n" |
| " mov r0, %0 \n" /* r0 = configMAX_SYSCALL_INTERRUPT_PRIORITY */ |
| " msr basepri, r0 \n" /* Disable interrupts up to configMAX_SYSCALL_INTERRUPT_PRIORITY. */ |
| " dsb \n" |
| " isb \n" |
| " bl vTaskSwitchContext \n" |
| " mov r0, #0 \n" /* r0 = 0. */ |
| " msr basepri, r0 \n" /* Enable interrupts. */ |
| " \n" |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* Read pxCurrentTCB. */ |
| " ldr r2, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. r2 now points to the top of stack. */ |
| " \n" |
| " ldmia r2!, {r0, r1, r4} \n" /* Read from stack - r0 = xSecureContext, r1 = PSPLIM and r4 = LR. */ |
| " msr psplim, r1 \n" /* Restore the PSPLIM register value for the task. */ |
| " mov lr, r4 \n" /* LR = r4. */ |
| " ldr r3, =xSecureContext \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */ |
| " str r0, [r3] \n" /* Restore the task's xSecureContext. */ |
| " cbz r0, restore_ns_context \n" /* If there is no secure context for the task, restore the non-secure context. */ |
| " ldr r3, =pxCurrentTCB \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ |
| " ldr r1, [r3] \n" /* Read pxCurrentTCB. */ |
| " push {r2, r4} \n" |
| " bl SecureContext_LoadContext \n" /* Restore the secure context. Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */ |
| " pop {r2, r4} \n" |
| " mov lr, r4 \n" /* LR = r4. */ |
| " lsls r1, r4, #25 \n" /* 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 \n" /* 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 \n" /* Remember the new top of stack for the task. */ |
| " bx lr \n" |
| " \n" |
| " restore_ns_context: \n" |
| " ldmia r2!, {r4-r11} \n" /* Restore the registers that are not automatically restored. */ |
| #if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) ) |
| " tst lr, #0x10 \n" /* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the Extended Stack Frame is in use. */ |
| " it eq \n" |
| " vldmiaeq r2!, {s16-s31} \n" /* Restore the additional FP context registers which are not restored automatically. */ |
| #endif /* configENABLE_FPU || configENABLE_MVE */ |
| " msr psp, r2 \n" /* Remember the new top of stack for the task. */ |
| " bx lr \n" |
| ::"i" ( configMAX_SYSCALL_INTERRUPT_PRIORITY ) |
| ); |
| } |
| |
| #endif /* configENABLE_MPU */ |
| /*-----------------------------------------------------------*/ |
| |
| #if ( ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) ) |
| |
| void SVC_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| ".syntax unified \n" |
| ".extern vPortSVCHandler_C \n" |
| ".extern vSystemCallEnter \n" |
| ".extern vSystemCallExit \n" |
| " \n" |
| "tst lr, #4 \n" |
| "ite eq \n" |
| "mrseq r0, msp \n" |
| "mrsne r0, psp \n" |
| " \n" |
| "ldr r1, [r0, #24] \n" |
| "ldrb r2, [r1, #-2] \n" |
| "cmp r2, %0 \n" |
| "blt syscall_enter \n" |
| "cmp r2, %1 \n" |
| "beq syscall_exit \n" |
| "b vPortSVCHandler_C \n" |
| " \n" |
| "syscall_enter: \n" |
| " mov r1, lr \n" |
| " b vSystemCallEnter \n" |
| " \n" |
| "syscall_exit: \n" |
| " mov r1, lr \n" |
| " b vSystemCallExit \n" |
| " \n" |
| : /* No outputs. */ |
| : "i" ( NUM_SYSTEM_CALLS ), "i" ( portSVC_SYSTEM_CALL_EXIT ) |
| : "r0", "r1", "r2", "memory" |
| ); |
| } |
| |
| #else /* ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) */ |
| |
| void SVC_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " tst lr, #4 \n" |
| " ite eq \n" |
| " mrseq r0, msp \n" |
| " mrsne r0, psp \n" |
| " ldr r1, =vPortSVCHandler_C \n" |
| " bx r1 \n" |
| ); |
| } |
| |
| #endif /* ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) */ |
| /*-----------------------------------------------------------*/ |
| |
| void vPortAllocateSecureContext( uint32_t ulSecureStackSize ) /* __attribute__ (( naked )) */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " svc %0 \n" /* Secure context is allocated in the supervisor call. */ |
| " bx lr \n" /* Return. */ |
| ::"i" ( portSVC_ALLOCATE_SECURE_CONTEXT ) : "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| void vPortFreeSecureContext( uint32_t * pulTCB ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ |
| { |
| __asm volatile |
| ( |
| " .syntax unified \n" |
| " \n" |
| " ldr r2, [r0] \n" /* The first item in the TCB is the top of the stack. */ |
| " ldr r1, [r2] \n" /* The first item on the stack is the task's xSecureContext. */ |
| " cmp r1, #0 \n" /* Raise svc if task's xSecureContext is not NULL. */ |
| " it ne \n" |
| " svcne %0 \n" /* Secure context is freed in the supervisor call. */ |
| " bx lr \n" /* Return. */ |
| ::"i" ( portSVC_FREE_SECURE_CONTEXT ) : "memory" |
| ); |
| } |
| /*-----------------------------------------------------------*/ |
