| /* | |
| * 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 | |
| * | |
| */ | |
| /* 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" | |
| /* 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_FPU == 1 ) | |
| #error Cortex-M23 does not have a Floating Point Unit (FPU) and therefore configENABLE_FPU must be set to 0. | |
| #endif | |
| void vRestoreContextOfFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ | |
| { | |
| __asm volatile | |
| ( | |
| " .syntax unified \n" | |
| " \n" | |
| " ldr r2, pxCurrentTCBConst2 \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" | |
| #if ( configENABLE_MPU == 1 ) | |
| " dmb \n"/* Complete outstanding transfers before disabling MPU. */ | |
| " ldr r2, xMPUCTRLConst2 \n"/* r2 = 0xe000ed94 [Location of MPU_CTRL]. */ | |
| " ldr r4, [r2] \n"/* Read the value of MPU_CTRL. */ | |
| " movs r5, #1 \n"/* r5 = 1. */ | |
| " bics r4, r5 \n"/* r4 = r4 & ~r5 i.e. Clear the bit 0 in r4. */ | |
| " str r4, [r2] \n"/* Disable MPU. */ | |
| " \n" | |
| " adds r3, #4 \n"/* r3 = r3 + 4. r3 now points to MAIR0 in TCB. */ | |
| " ldr r4, [r3] \n"/* r4 = *r3 i.e. r4 = MAIR0. */ | |
| " ldr r2, xMAIR0Const2 \n"/* r2 = 0xe000edc0 [Location of MAIR0]. */ | |
| " str r4, [r2] \n"/* Program MAIR0. */ | |
| " ldr r2, xRNRConst2 \n"/* r2 = 0xe000ed98 [Location of RNR]. */ | |
| " adds r3, #4 \n"/* r3 = r3 + 4. r3 now points to first RBAR in TCB. */ | |
| " movs r5, #4 \n"/* r5 = 4. */ | |
| " str r5, [r2] \n"/* Program RNR = 4. */ | |
| " ldmia r3!, {r6,r7} \n"/* Read first set of RBAR/RLAR from TCB. */ | |
| " ldr r4, xRBARConst2 \n"/* r4 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r4!, {r6,r7} \n"/* Write first set of RBAR/RLAR registers. */ | |
| " movs r5, #5 \n"/* r5 = 5. */ | |
| " str r5, [r2] \n"/* Program RNR = 5. */ | |
| " ldmia r3!, {r6,r7} \n"/* Read second set of RBAR/RLAR from TCB. */ | |
| " ldr r4, xRBARConst2 \n"/* r4 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r4!, {r6,r7} \n"/* Write second set of RBAR/RLAR registers. */ | |
| " movs r5, #6 \n"/* r5 = 6. */ | |
| " str r5, [r2] \n"/* Program RNR = 6. */ | |
| " ldmia r3!, {r6,r7} \n"/* Read third set of RBAR/RLAR from TCB. */ | |
| " ldr r4, xRBARConst2 \n"/* r4 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r4!, {r6,r7} \n"/* Write third set of RBAR/RLAR registers. */ | |
| " movs r5, #7 \n"/* r5 = 7. */ | |
| " str r5, [r2] \n"/* Program RNR = 7. */ | |
| " ldmia r3!, {r6,r7} \n"/* Read fourth set of RBAR/RLAR from TCB. */ | |
| " ldr r4, xRBARConst2 \n"/* r4 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r4!, {r6,r7} \n"/* Write fourth set of RBAR/RLAR registers. */ | |
| " \n" | |
| " ldr r2, xMPUCTRLConst2 \n"/* r2 = 0xe000ed94 [Location of MPU_CTRL]. */ | |
| " ldr r4, [r2] \n"/* Read the value of MPU_CTRL. */ | |
| " movs r5, #1 \n"/* r5 = 1. */ | |
| " orrs r4, r5 \n"/* r4 = r4 | r5 i.e. Set the bit 0 in r4. */ | |
| " str r4, [r2] \n"/* Enable MPU. */ | |
| " dsb \n"/* Force memory writes before continuing. */ | |
| #endif /* configENABLE_MPU */ | |
| " \n" | |
| #if ( configENABLE_MPU == 1 ) | |
| " ldm r0!, {r1-r4} \n"/* Read from stack - r1 = xSecureContext, r2 = PSPLIM, r3 = CONTROL and r4 = EXC_RETURN. */ | |
| " ldr r5, xSecureContextConst2 \n" | |
| " str r1, [r5] \n"/* Set xSecureContext to this task's value for the same. */ | |
| " msr psplim, r2 \n"/* Set this task's PSPLIM value. */ | |
| " msr control, r3 \n"/* Set this task's CONTROL 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" | |
| " bx r4 \n"/* Finally, branch to EXC_RETURN. */ | |
| #else /* configENABLE_MPU */ | |
| " ldm r0!, {r1-r3} \n"/* Read from stack - r1 = xSecureContext, r2 = PSPLIM and r3 = EXC_RETURN. */ | |
| " ldr r4, xSecureContextConst2 \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. */ | |
| " movs r1, #2 \n"/* r1 = 2. */ | |
| " msr CONTROL, r1 \n"/* Switch to use PSP in the thread mode. */ | |
| " 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" | |
| " bx r3 \n"/* Finally, branch to EXC_RETURN. */ | |
| #endif /* configENABLE_MPU */ | |
| " \n" | |
| " .align 4 \n" | |
| "pxCurrentTCBConst2: .word pxCurrentTCB \n" | |
| "xSecureContextConst2: .word xSecureContext \n" | |
| #if ( configENABLE_MPU == 1 ) | |
| "xMPUCTRLConst2: .word 0xe000ed94 \n" | |
| "xMAIR0Const2: .word 0xe000edc0 \n" | |
| "xRNRConst2: .word 0xe000ed98 \n" | |
| "xRBARConst2: .word 0xe000ed9c \n" | |
| #endif /* configENABLE_MPU */ | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| BaseType_t xIsPrivileged( void ) /* __attribute__ (( naked )) */ | |
| { | |
| __asm volatile | |
| ( | |
| " mrs r0, control \n"/* r0 = CONTROL. */ | |
| " movs r1, #1 \n"/* r1 = 1. */ | |
| " tst r0, r1 \n"/* Perform r0 & r1 (bitwise AND) and update the conditions flag. */ | |
| " beq running_privileged \n"/* If the result of previous AND operation was 0, branch. */ | |
| " movs r0, #0 \n"/* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */ | |
| " bx lr \n"/* Return. */ | |
| " running_privileged: \n" | |
| " movs r0, #1 \n"/* CONTROL[0]==0. Return true to indicate that the processor is privileged. */ | |
| " bx lr \n"/* Return. */ | |
| " \n" | |
| " .align 4 \n" | |
| ::: "r0", "r1", "memory" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vRaisePrivilege( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ | |
| { | |
| __asm volatile | |
| ( | |
| " mrs r0, control \n"/* Read the CONTROL register. */ | |
| " movs r1, #1 \n"/* r1 = 1. */ | |
| " bics r0, r1 \n"/* Clear the bit 0. */ | |
| " msr control, r0 \n"/* Write back the new CONTROL value. */ | |
| " bx lr \n"/* Return to the caller. */ | |
| ::: "r0", "r1", "memory" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vResetPrivilege( void ) /* __attribute__ (( naked )) */ | |
| { | |
| __asm volatile | |
| ( | |
| " mrs r0, control \n"/* r0 = CONTROL. */ | |
| " movs r1, #1 \n"/* r1 = 1. */ | |
| " orrs r0, r1 \n"/* r0 = r0 | r1. */ | |
| " msr control, r0 \n"/* CONTROL = r0. */ | |
| " bx lr \n"/* Return to the caller. */ | |
| ::: "r0", "r1", "memory" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vStartFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ | |
| { | |
| __asm volatile | |
| ( | |
| " ldr r0, xVTORConst \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. */ | |
| " dsb \n" | |
| " isb \n" | |
| " svc %0 \n"/* System call to start the first task. */ | |
| " nop \n" | |
| " \n" | |
| " .align 4 \n" | |
| "xVTORConst: .word 0xe000ed08 \n" | |
| ::"i" ( portSVC_START_SCHEDULER ) : "memory" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| uint32_t ulSetInterruptMask( void ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */ | |
| { | |
| __asm volatile | |
| ( | |
| " mrs r0, PRIMASK \n" | |
| " cpsid i \n" | |
| " bx lr \n" | |
| ::: "memory" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */ | |
| { | |
| __asm volatile | |
| ( | |
| " msr PRIMASK, r0 \n" | |
| " bx lr \n" | |
| ::: "memory" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ | |
| { | |
| __asm volatile | |
| ( | |
| " .syntax unified \n" | |
| " .extern SecureContext_SaveContext \n" | |
| " .extern SecureContext_LoadContext \n" | |
| " \n" | |
| " ldr r3, xSecureContextConst \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, pxCurrentTCBConst \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. */ | |
| " ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ | |
| " ldr r1, [r3] \n"/* Read pxCurrentTCB. */ | |
| #if ( configENABLE_MPU == 1 ) | |
| " subs r2, r2, #16 \n"/* Make space for xSecureContext, PSPLIM, CONTROL and LR on the stack. */ | |
| " str r2, [r1] \n"/* Save the new top of stack in TCB. */ | |
| " mrs r1, psplim \n"/* r1 = PSPLIM. */ | |
| " mrs r3, control \n"/* r3 = CONTROL. */ | |
| " mov r4, lr \n"/* r4 = LR/EXC_RETURN. */ | |
| " stmia r2!, {r0, r1, r3, r4} \n"/* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */ | |
| #else /* configENABLE_MPU */ | |
| " 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. */ | |
| #endif /* configENABLE_MPU */ | |
| " b select_next_task \n" | |
| " \n" | |
| " save_ns_context: \n" | |
| " ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */ | |
| " ldr r1, [r3] \n"/* Read pxCurrentTCB. */ | |
| #if ( configENABLE_MPU == 1 ) | |
| " subs r2, r2, #48 \n"/* Make space for xSecureContext, PSPLIM, CONTROL, LR and the remaining registers on the stack. */ | |
| " str r2, [r1] \n"/* Save the new top of stack in TCB. */ | |
| " adds r2, r2, #16 \n"/* r2 = r2 + 16. */ | |
| " stmia r2!, {r4-r7} \n"/* Store the low registers that are not saved automatically. */ | |
| " mov r4, r8 \n"/* r4 = r8. */ | |
| " mov r5, r9 \n"/* r5 = r9. */ | |
| " mov r6, r10 \n"/* r6 = r10. */ | |
| " mov r7, r11 \n"/* r7 = r11. */ | |
| " stmia r2!, {r4-r7} \n"/* Store the high registers that are not saved automatically. */ | |
| " mrs r1, psplim \n"/* r1 = PSPLIM. */ | |
| " mrs r3, control \n"/* r3 = CONTROL. */ | |
| " mov r4, lr \n"/* r4 = LR/EXC_RETURN. */ | |
| " subs r2, r2, #48 \n"/* r2 = r2 - 48. */ | |
| " stmia r2!, {r0, r1, r3, r4} \n"/* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */ | |
| #else /* configENABLE_MPU */ | |
| " 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. */ | |
| " mrs r1, psplim \n"/* r1 = PSPLIM. */ | |
| " mov r3, lr \n"/* r3 = LR/EXC_RETURN. */ | |
| " stmia r2!, {r0, r1, r3-r7} \n"/* Store xSecureContext, PSPLIM, LR and the low registers that are not saved automatically. */ | |
| " mov r4, r8 \n"/* r4 = r8. */ | |
| " mov r5, r9 \n"/* r5 = r9. */ | |
| " mov r6, r10 \n"/* r6 = r10. */ | |
| " mov r7, r11 \n"/* r7 = r11. */ | |
| " stmia r2!, {r4-r7} \n"/* Store the high registers that are not saved automatically. */ | |
| #endif /* configENABLE_MPU */ | |
| " \n" | |
| " select_next_task: \n" | |
| " cpsid i \n" | |
| " bl vTaskSwitchContext \n" | |
| " cpsie i \n" | |
| " \n" | |
| " ldr r3, pxCurrentTCBConst \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" | |
| #if ( configENABLE_MPU == 1 ) | |
| " dmb \n"/* Complete outstanding transfers before disabling MPU. */ | |
| " ldr r3, xMPUCTRLConst \n"/* r3 = 0xe000ed94 [Location of MPU_CTRL]. */ | |
| " ldr r4, [r3] \n"/* Read the value of MPU_CTRL. */ | |
| " movs r5, #1 \n"/* r5 = 1. */ | |
| " bics r4, r5 \n"/* r4 = r4 & ~r5 i.e. Clear the bit 0 in r4. */ | |
| " str r4, [r3] \n"/* Disable MPU. */ | |
| " \n" | |
| " adds r1, #4 \n"/* r1 = r1 + 4. r1 now points to MAIR0 in TCB. */ | |
| " ldr r4, [r1] \n"/* r4 = *r1 i.e. r4 = MAIR0. */ | |
| " ldr r3, xMAIR0Const \n"/* r3 = 0xe000edc0 [Location of MAIR0]. */ | |
| " str r4, [r3] \n"/* Program MAIR0. */ | |
| " ldr r4, xRNRConst \n"/* r4 = 0xe000ed98 [Location of RNR]. */ | |
| " adds r1, #4 \n"/* r1 = r1 + 4. r1 now points to first RBAR in TCB. */ | |
| " movs r5, #4 \n"/* r5 = 4. */ | |
| " str r5, [r4] \n"/* Program RNR = 4. */ | |
| " ldmia r1!, {r6,r7} \n"/* Read first set of RBAR/RLAR from TCB. */ | |
| " ldr r3, xRBARConst \n"/* r3 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r3!, {r6,r7} \n"/* Write first set of RBAR/RLAR registers. */ | |
| " movs r5, #5 \n"/* r5 = 5. */ | |
| " str r5, [r4] \n"/* Program RNR = 5. */ | |
| " ldmia r1!, {r6,r7} \n"/* Read second set of RBAR/RLAR from TCB. */ | |
| " ldr r3, xRBARConst \n"/* r3 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r3!, {r6,r7} \n"/* Write second set of RBAR/RLAR registers. */ | |
| " movs r5, #6 \n"/* r5 = 6. */ | |
| " str r5, [r4] \n"/* Program RNR = 6. */ | |
| " ldmia r1!, {r6,r7} \n"/* Read third set of RBAR/RLAR from TCB. */ | |
| " ldr r3, xRBARConst \n"/* r3 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r3!, {r6,r7} \n"/* Write third set of RBAR/RLAR registers. */ | |
| " movs r5, #7 \n"/* r5 = 7. */ | |
| " str r5, [r4] \n"/* Program RNR = 7. */ | |
| " ldmia r1!, {r6,r7} \n"/* Read fourth set of RBAR/RLAR from TCB. */ | |
| " ldr r3, xRBARConst \n"/* r3 = 0xe000ed9c [Location of RBAR]. */ | |
| " stmia r3!, {r6,r7} \n"/* Write fourth set of RBAR/RLAR registers. */ | |
| " \n" | |
| " ldr r3, xMPUCTRLConst \n"/* r3 = 0xe000ed94 [Location of MPU_CTRL]. */ | |
| " ldr r4, [r3] \n"/* Read the value of MPU_CTRL. */ | |
| " movs r5, #1 \n"/* r5 = 1. */ | |
| " orrs r4, r5 \n"/* r4 = r4 | r5 i.e. Set the bit 0 in r4. */ | |
| " str r4, [r3] \n"/* Enable MPU. */ | |
| " dsb \n"/* Force memory writes before continuing. */ | |
| #endif /* configENABLE_MPU */ | |
| " \n" | |
| #if ( configENABLE_MPU == 1 ) | |
| " ldmia r2!, {r0, r1, r3, r4} \n"/* Read from stack - r0 = xSecureContext, r1 = PSPLIM, r3 = CONTROL and r4 = LR. */ | |
| " msr psplim, r1 \n"/* Restore the PSPLIM register value for the task. */ | |
| " msr control, r3 \n"/* Restore the CONTROL register value for the task. */ | |
| " mov lr, r4 \n"/* LR = r4. */ | |
| " ldr r3, xSecureContextConst \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, pxCurrentTCBConst \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" | |
| #else /* configENABLE_MPU */ | |
| " 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, xSecureContextConst \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, pxCurrentTCBConst \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" | |
| #endif /* configENABLE_MPU */ | |
| " \n" | |
| " restore_ns_context: \n" | |
| " adds r2, r2, #16 \n"/* Move to the high registers. */ | |
| " ldmia r2!, {r4-r7} \n"/* Restore the high registers that are not automatically restored. */ | |
| " mov r8, r4 \n"/* r8 = r4. */ | |
| " mov r9, r5 \n"/* r9 = r5. */ | |
| " mov r10, r6 \n"/* r10 = r6. */ | |
| " mov r11, r7 \n"/* r11 = r7. */ | |
| " msr psp, r2 \n"/* Remember the new top of stack for the task. */ | |
| " subs r2, r2, #32 \n"/* Go back to the low registers. */ | |
| " ldmia r2!, {r4-r7} \n"/* Restore the low registers that are not automatically restored. */ | |
| " bx lr \n" | |
| " \n" | |
| " .align 4 \n" | |
| "pxCurrentTCBConst: .word pxCurrentTCB \n" | |
| "xSecureContextConst: .word xSecureContext \n" | |
| #if ( configENABLE_MPU == 1 ) | |
| "xMPUCTRLConst: .word 0xe000ed94 \n" | |
| "xMAIR0Const: .word 0xe000edc0 \n" | |
| "xRNRConst: .word 0xe000ed98 \n" | |
| "xRBARConst: .word 0xe000ed9c \n" | |
| #endif /* configENABLE_MPU */ | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void SVC_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */ | |
| { | |
| __asm volatile | |
| ( | |
| " movs r0, #4 \n" | |
| " mov r1, lr \n" | |
| " tst r0, r1 \n" | |
| " beq stacking_used_msp \n" | |
| " mrs r0, psp \n" | |
| " ldr r2, svchandler_address_const \n" | |
| " bx r2 \n" | |
| " stacking_used_msp: \n" | |
| " mrs r0, msp \n" | |
| " ldr r2, svchandler_address_const \n" | |
| " bx r2 \n" | |
| " \n" | |
| " .align 4 \n" | |
| "svchandler_address_const: .word vPortSVCHandler_C \n" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vPortAllocateSecureContext( uint32_t ulSecureStackSize ) /* __attribute__ (( naked )) */ | |
| { | |
| __asm volatile | |
| ( | |
| " 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 | |
| ( | |
| " 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. */ | |
| " bne free_secure_context \n"/* Branch if r1 != 0. */ | |
| " bx lr \n"/* There is no secure context (xSecureContext is NULL). */ | |
| " free_secure_context: \n" | |
| " svc %0 \n"/* Secure context is freed in the supervisor call. */ | |
| " bx lr \n"/* Return. */ | |
| ::"i" ( portSVC_FREE_SECURE_CONTEXT ) : "memory" | |
| ); | |
| } | |
| /*-----------------------------------------------------------*/ |