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Update RISC-V port to use a separate interrupt stack.

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pull/1/head
Richard Barry 6 years ago
parent e85ea96f78
commit 65f7a2dc19
3 changed files with 78 additions and 24 deletions
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56
FreeRTOS/Source/portable/GCC/RISC-V-RV32/port.c
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@ -34,6 +34,16 @@
#include "task.h"
#include "portmacro.h"
#ifdef configISR_STACK_SIZE
/* The stack used by interrupt service routines. */
static __attribute__ ((aligned(16))) StackType_t xISRStack[ configISR_STACK_SIZE ] = { 0 };
const StackType_t * const xISRStackTop = &( xISRStack[ ( configISR_STACK_SIZE & ~portBYTE_ALIGNMENT_MASK ) - 1 ] );
#else
#warning What should _sp be named?
extern const uint32_t _sp[];
const uint32_t xISRStackTop = ( uint32_t ) _sp;
#endif
/*
* Setup the timer to generate the tick interrupts. The implementation in this
* file is weak to allow application writers to change the timer used to
@ -54,6 +64,30 @@ const uint64_t *pullNextTime = &ullNextTime;
const uint32_t ulTimerIncrementsForOneTick = ( uint32_t ) ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ); /* Assumes increment won't go over 32-bits. */
volatile uint64_t * const pullMachineTimerCompareRegister = ( volatile uint64_t * const ) ( configCLINT_BASE_ADDRESS + 0x4000 );
/* Set configCHECK_FOR_STACK_OVERFLOW to 3 to add ISR stack checking to task
stack checking. A problem in the ISR stack will trigger an assert, not call the
stack overflow hook function (because the stack overflow hook is specific to a
task stack, not the ISR stack). */
#if( configCHECK_FOR_STACK_OVERFLOW > 2 )
#warning This path not tested, or even compiled yet.
/* Don't use 0xa5 as the stack fill bytes as that is used by the kernerl for
the task stacks, and so will legitimately appear in many positions within
the ISR stack. */
#define portISR_STACK_FILL_BYTE 0xee
static const uint8_t ucExpectedStackBytes[] = {
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE }; \
#define portCHECK_ISR_STACK() configASSERT( ( memcmp( ( void * ) xISRStack, ( void * ) ucExpectedStackBytes, sizeof( ucExpectedStackBytes ) ) == 0 ) )
#else
/* Define the function away. */
#define portCHECK_ISR_STACK()
#endif /* configCHECK_FOR_STACK_OVERFLOW > 2 */
/*-----------------------------------------------------------*/
void prvTaskExitError( void )
@ -194,22 +228,11 @@ volatile uint32_t * const pulTimeLow = ( volatile uint32_t * const ) ( configCLI
/* Prepare the time to use after the next tick interrupt. */
ullNextTime += ( uint64_t ) ulTimerIncrementsForOneTick;
/* Enable timer interrupt */
/* Enable timer interrupt. */
__asm volatile( "csrs mie, %0" :: "r"(0x80) ); /* 1<<7 for timer interrupt. */
}
/*-----------------------------------------------------------*/
void Software_IRQHandler( void )
{
volatile uint32_t * const ulSoftInterrupt = ( uint32_t * ) configCLINT_BASE_ADDRESS;
vTaskSwitchContext();
/* Clear software interrupt. */
*( ( uint32_t * ) configCLINT_BASE_ADDRESS ) &= 0x08UL;
}
/*-----------------------------------------------------------*/
BaseType_t xPortStartScheduler( void )
{
extern void xPortStartFirstTask( void );
@ -218,10 +241,15 @@ extern void xPortStartFirstTask( void );
{
volatile uint32_t mtvec = 0;
/* Check the least significant two bits of mtvec are 00 - indicating single
vector mode. */
/* Check the least significant two bits of mtvec are 00 - indicating
single vector mode. */
__asm volatile( "csrr %0, mtvec" : "=r"( mtvec ) );
configASSERT( ( mtvec & 0x03UL ) == 0 );
/* Check alignment of the interrupt stack - which is the same as the
stack that was being used by main() prior to the scheduler being
started. */
configASSERT( ( xISRStackTop & portBYTE_ALIGNMENT_MASK ) == 0 );
}
#endif

9
FreeRTOS/Source/portable/GCC/RISC-V-RV32/portASM.S
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@ -49,7 +49,7 @@
.extern pullMachineTimerCompareRegister
.extern pullNextTime
.extern ulTimerIncrementsForOneTick
.extern xISRStackTop
/*-----------------------------------------------------------*/
@ -136,14 +136,13 @@ vPortTrapHandler:
csrr a0, mcause
csrr a1, mepc
mv a2, sp
test_if_environment_call:
li t0, 11 /* 11 == environment call when using qemu. */
bne a0, t0, test_if_timer
addi a1, a1, 4 /* Synchronous so return to the instruction after the environment call. */
sw a1, 0( sp ) /* Save updated exception return address. */
/*_RB_ Does stack need aligning here? */
lw sp, xISRStackTop /* Switch to ISR stack before function call. */
jal vTaskSwitchContext
j processed_source
@ -167,13 +166,15 @@ test_if_timer:
add t6, t3, t5 /* Add overflow to high word of ullNextTime. */
sw t4, 0(t1) /* Store new low word of ullNextTime. */
sw t6, 4(t1) /* Store new high word of ullNextTime. */
lw sp, xISRStackTop /* Switch to ISR stack before function call. */
jal xTaskIncrementTick
beqz a0, processed_source /* Don't switch context if incrementing tick didn't unblock a task. */
jal vTaskSwitchContext
j processed_source
as_yet_unhandled:
j as_yet_unhandled /* External interrupt? */
// ebreak /* External interrupt? */
j as_yet_unhandled
processed_source:
lw sp, pxCurrentTCB /* Load pxCurrentTCB. */

37
FreeRTOS/Source/portable/GCC/RISC-V-RV32/portmacro.h
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@ -70,8 +70,9 @@ not need to be guarded with a critical section. */
/* Scheduler utilities. */
#define portYIELD() __asm volatile( "ecall" ); // software interrupt alternative *( ( uint32_t * ) configCLINT_BASE_ADDRESS ) |= 0x08UL
#define portEND_SWITCHING_ISR( xSwitchRequired ) if( xSwitchRequired ) vPortYield()
extern void vTaskSwitchContext( void );
#define portYIELD() __asm volatile( "ecall" );
#define portEND_SWITCHING_ISR( xSwitchRequired ) if( xSwitchRequired ) vTaskSwitchContext()
#define portYIELD_FROM_ISR( x ) portEND_SWITCHING_ISR( x )
/*-----------------------------------------------------------*/
@ -84,12 +85,37 @@ extern void vTaskEnterCritical( void );
extern void vTaskExitCritical( void );
#define portSET_INTERRUPT_MASK_FROM_ISR() 0
#define portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedStatusValue )
#define portDISABLE_INTERRUPTS() __asm volatile( "csrc mstatus, 8" )
#define portENABLE_INTERRUPTS() __asm volatile( "csrs mstatus, 8" )
#define portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedStatusValue ) ( void ) uxSavedStatusValue
#define portDISABLE_INTERRUPTS() __asm volatile( "csrc mstatus, 8" ); __asm volatile( "fence" )
#define portENABLE_INTERRUPTS() __asm volatile( "csrs mstatus, 8" ); __asm volatile( "fence" )
#define portENTER_CRITICAL() vTaskEnterCritical()
#define portEXIT_CRITICAL() vTaskExitCritical()
/*-----------------------------------------------------------*/
/* Architecture specific optimisations. */
#ifndef configUSE_PORT_OPTIMISED_TASK_SELECTION
#define configUSE_PORT_OPTIMISED_TASK_SELECTION 1
#endif
#if( configUSE_PORT_OPTIMISED_TASK_SELECTION == 1 )
/* Check the configuration. */
#if( configMAX_PRIORITIES > 32 )
#error configUSE_PORT_OPTIMISED_TASK_SELECTION can only be set to 1 when configMAX_PRIORITIES is less than or equal to 32. It is very rare that a system requires more than 10 to 15 difference priorities as tasks that share a priority will time slice.
#endif
/* Store/clear the ready priorities in a bit map. */
#define portRECORD_READY_PRIORITY( uxPriority, uxReadyPriorities ) ( uxReadyPriorities ) |= ( 1UL << ( uxPriority ) )
#define portRESET_READY_PRIORITY( uxPriority, uxReadyPriorities ) ( uxReadyPriorities ) &= ~( 1UL << ( uxPriority ) )
/*-----------------------------------------------------------*/
#define portGET_HIGHEST_PRIORITY( uxTopPriority, uxReadyPriorities ) uxTopPriority = ( 31UL - __builtin_clz( uxReadyPriorities ) )
#endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */
/*-----------------------------------------------------------*/
/* Task function macros as described on the FreeRTOS.org WEB site. These are
@ -107,7 +133,6 @@ not necessary for to use this port. They are defined so the common demo files
#ifndef portFORCE_INLINE
#define portFORCE_INLINE inline __attribute__(( always_inline))
#endif
portFORCE_INLINE static BaseType_t xPortIsInsideInterrupt( void ) {}
#ifdef __cplusplus
}

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