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Update ARM_CRx_No_GIC port (#1101)

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This PR makes the following improvements to the ARM_CRx_No_GIC port-

1. Remove inline assembly and move all the assembly code to the portASM.S
    file.

2. Add support for configUSE_TASK_FPU_SUPPORT -
   - When configUSE_TASK_FPU_SUPPORT is defined to 1, tasks are created
      without floating point context. Tasks that want to use floating point, need
      to call portTASK_USES_FLOATING_POINT(). This is the current behavior.
   - When configUSE_TASK_FPU_SUPPORT is defined to 2, each task is created
      with a floating point context.
  If left undefined, configUSE_TASK_FPU_SUPPORT defaults to 1 for backward compatibility.

3. The application writer can now implement vApplicationSVCHandler to handle the
    SVC calls raised within the application. SVC 0 is used for the yield kernel operation
    and the application can use all the SVC calls other than 0.

Signed-off-by: kar-rahul-aws <karahulx@amazon.com>
This commit is contained in:
Rahul Kar 2024-07-22 21:05:17 +05:30 • committed by GitHub
parent 0452603a94
commit 5588ae68c8
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GPG key ID: B5690EEEBB952194
3 changed files with 308 additions and 148 deletions
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67
portable/GCC/ARM_CRx_No_GIC/port.c
View file

@ -28,6 +28,7 @@
/* Standard includes. */
#include <stdlib.h>
#include <string.h>
/* Scheduler includes. */
#include "FreeRTOS.h"
@ -80,13 +81,22 @@
#define portTASK_RETURN_ADDRESS prvTaskExitError
#endif
/* The space on the stack required to hold the FPU registers. */
#if ( configFPU_D32 == 1 )
#define portFPU_REGISTER_WORDS ( ( 32 * 2 ) + 1 ) /* D0-D31 and FPSCR. */
#else
#define portFPU_REGISTER_WORDS ( ( 16 * 2 ) + 1 ) /* D0-D15 and FPSCR. */
#endif /* configFPU_D32 */
/*-----------------------------------------------------------*/
/*
* Starts the first task executing. This function is necessarily written in
* assembly code so is implemented in portASM.s.
* These functions are necessarily written in assembly code, so are implemented
* in portASM.S.
*/
extern void vPortRestoreTaskContext( void );
extern void vPortInitialiseFPSCR( void );
extern uint32_t ulReadAPSR( void );
/*
* Used to catch tasks that attempt to return from their implementing function.
@ -184,12 +194,33 @@ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
/* The task will start with a critical nesting count of 0 as interrupts are
* enabled. */
*pxTopOfStack = portNO_CRITICAL_NESTING;
pxTopOfStack--;
/* The task will start without a floating point context. A task that uses
* the floating point hardware must call vPortTaskUsesFPU() before executing
* any floating point instructions. */
*pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
#if ( configUSE_TASK_FPU_SUPPORT == 1 )
{
/* The task will start without a floating point context. A task that uses
* the floating point hardware must call vPortTaskUsesFPU() before executing
* any floating point instructions. */
pxTopOfStack--;
*pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
}
#elif ( configUSE_TASK_FPU_SUPPORT == 2 )
{
/* The task will start with a floating point context. Leave enough
* space for the registers - and ensure they are initialised to 0. */
pxTopOfStack -= portFPU_REGISTER_WORDS;
memset( pxTopOfStack, 0x00, portFPU_REGISTER_WORDS * sizeof( StackType_t ) );
/* Initialise the slot containing ulPortTaskHasFPUContext to true as
* the task starts with a floating point context. */
pxTopOfStack--;
*pxTopOfStack = pdTRUE;
ulPortTaskHasFPUContext = pdTRUE;
}
#else
{
#error "Invalid configUSE_TASK_FPU_SUPPORT value - configUSE_TASK_FPU_SUPPORT must be set to 1, 2, or left undefined."
}
#endif /* if ( configUSE_TASK_FPU_SUPPORT == 1 ) */
return pxTopOfStack;
}
@ -218,7 +249,7 @@ BaseType_t xPortStartScheduler( void )
/* Only continue if the CPU is not in User mode. The CPU must be in a
* Privileged mode for the scheduler to start. */
__asm volatile ( "MRS %0, APSR" : "=r" ( ulAPSR )::"memory" );
ulAPSR = ulReadAPSR();
ulAPSR &= portAPSR_MODE_BITS_MASK;
configASSERT( ulAPSR != portAPSR_USER_MODE );
@ -310,15 +341,17 @@ void FreeRTOS_Tick_Handler( void )
}
/*-----------------------------------------------------------*/
void vPortTaskUsesFPU( void )
{
uint32_t ulInitialFPSCR = 0;
#if ( configUSE_TASK_FPU_SUPPORT != 2 )
/* A task is registering the fact that it needs an FPU context. Set the
* FPU flag (which is saved as part of the task context). */
ulPortTaskHasFPUContext = pdTRUE;
void vPortTaskUsesFPU( void )
{
/* A task is registering the fact that it needs an FPU context. Set the
* FPU flag (which is saved as part of the task context). */
ulPortTaskHasFPUContext = pdTRUE;
/* Initialise the floating point status register. */
__asm volatile ( "FMXR FPSCR, %0" ::"r" ( ulInitialFPSCR ) : "memory" );
}
/* Initialise the floating point status register. */
vPortInitialiseFPSCR();
}
#endif /* configUSE_TASK_FPU_SUPPORT */
/*-----------------------------------------------------------*/