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Detect more startup config errors on Cortex M (#832)

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Verify that the application has correctly installed PendSV
and SVCall handlers. The application can choose to
disable these checks by setting configCHECK_HANDLER_INSTALLATION
to 0 in their FreeRTOSConfig.h.
This commit is contained in:
Jeff Tenney 2023-12-10 21:57:47 -07:00 • committed by GitHub
parent 553caa18ce
commit 30e6b8a5ea
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GPG key ID: 4AEE18F83AFDEB23
35 changed files with 1765 additions and 350 deletions
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58
portable/GCC/ARM_CM0/port.c
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@ -34,6 +34,9 @@
#include "FreeRTOS.h"
#include "task.h"
/* Prototype of all Interrupt Service Routines (ISRs). */
typedef void ( * portISR_t )( void );
/* Constants required to manipulate the NVIC. */
#define portNVIC_SYSTICK_CTRL_REG ( *( ( volatile uint32_t * ) 0xe000e010 ) )
#define portNVIC_SYSTICK_LOAD_REG ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@ -51,6 +54,10 @@
#define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL )
#define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL )
/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
#define portSCB_VTOR_REG ( *( ( portISR_t ** ) 0xe000ed08 ) )
#define portVECTOR_INDEX_PENDSV ( 14 )
/* Constants required to set up the initial stack. */
#define portINITIAL_XPSR ( 0x01000000 )
@ -200,20 +207,20 @@ void vPortSVCHandler( void )
void vPortStartFirstTask( void )
{
/* The MSP stack is not reset as, unlike on M3/4 parts, there is no vector
* table offset register that can be used to locate the initial stack value.
* Not all M0 parts have the application vector table at address 0. */
/* Don't reset the MSP stack as is done on CM3/4 devices. The vector table
* in some CM0 devices cannot be modified and thus may not hold the
* application's initial MSP value. */
__asm volatile (
" .syntax unified \n"
" ldr r2, pxCurrentTCBConst2 \n" /* Obtain location of pxCurrentTCB. */
" ldr r3, [r2] \n"
" ldr r0, [r3] \n" /* The first item in pxCurrentTCB is the task top of stack. */
" 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. */
" 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. */
" movs r0, #2 \n" /* Switch to the psp stack. */
" msr CONTROL, r0 \n"
" msr CONTROL, r0 \n"
" isb \n"
" pop {r0-r5} \n" /* Pop the registers that are saved automatically. */
" pop {r0-r5} \n" /* Pop the registers that are saved automatically. */
" mov lr, r5 \n" /* lr is now in r5. */
" pop {r3} \n" /* Return address is now in r3. */
" pop {r2} \n" /* Pop and discard XPSR. */
@ -231,7 +238,42 @@ void vPortStartFirstTask( void )
*/
BaseType_t xPortStartScheduler( void )
{
/* Make PendSV, CallSV and SysTick the same priority as the kernel. */
/* An application can install FreeRTOS interrupt handlers in one of the
* folllowing ways:
* 1. Direct Routing - Install the function xPortPendSVHandler for PendSV
* interrupt.
* 2. Indirect Routing - Install separate handler for PendSV interrupt and
* route program control from that handler to xPortPendSVHandler function.
*
* Applications that use Indirect Routing must set
* configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
* routing, which is validated here when configCHECK_HANDLER_INSTALLATION
* is 1, should be preferred when possible. */
#if ( configCHECK_HANDLER_INSTALLATION == 1 )
{
/* Point pxVectorTable to the interrupt vector table. Systems without
* a VTOR register provide the value zero in the VTOR register and
* the vector table itself is located at the address 0x00000000. */
const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
/* Validate that the application has correctly installed the FreeRTOS
* handler for PendSV interrupt. We do not check the installation of the
* SysTick handler because the application may choose to drive the RTOS
* tick using a timer other than the SysTick timer by overriding the
* weak function vPortSetupTimerInterrupt().
*
* Assertion failures here indicate incorrect installation of the
* FreeRTOS handler. For help installing the FreeRTOS handler, see
* https://www.FreeRTOS.org/FAQHelp.html.
*
* Systems with a configurable address for the interrupt vector table
* can also encounter assertion failures or even system faults here if
* VTOR is not set correctly to point to the application's vector table. */
configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
}
#endif /* configCHECK_HANDLER_INSTALLATION */
/* Make PendSV and SysTick the lowest priority interrupts. */
portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;