Add option to disable unprivileged critical sections

This commit introduces a new config
configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS which enables developers to
prevent critical sections from unprivileged tasks. It defaults to 1 for
backward compatibility. Application should set it to 0 to disable
critical sections from unprivileged tasks.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
This commit is contained in:
Gaurav Aggarwal 2021-10-06 19:00:39 -07:00 committed by Gaurav-Aggarwal-AWS
parent 7a3848753b
commit 44fc137428
4 changed files with 92 additions and 8 deletions

View file

@ -52,6 +52,11 @@
#define portNVIC_SYSTICK_CLK ( 0 )
#endif
#ifndef configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS
#warning "configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS is not defined. We recommend defining it to 0 in FreeRTOSConfig.h for better security."
#define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS 1
#endif
/* Constants required to access and manipulate the NVIC. */
#define portNVIC_SYSTICK_CTRL_REG ( *( ( volatile uint32_t * ) 0xe000e010 ) )
#define portNVIC_SYSTICK_LOAD_REG ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@ -162,12 +167,20 @@ void vResetPrivilege( void ) __attribute__( ( naked ) );
/**
* @brief Enter critical section.
*/
void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
#else
void vPortEnterCritical( void ) PRIVILEGED_FUNCTION;
#endif
/**
* @brief Exit from critical section.
*/
void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
#else
void vPortExitCritical( void ) PRIVILEGED_FUNCTION;
#endif
/*-----------------------------------------------------------*/
/* Each task maintains its own interrupt status in the critical nesting
@ -480,20 +493,26 @@ void vPortEndScheduler( void )
void vPortEnterCritical( void )
{
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
BaseType_t xRunningPrivileged;
xPortRaisePrivilege( xRunningPrivileged );
#endif
portDISABLE_INTERRUPTS();
uxCriticalNesting++;
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
vPortResetPrivilege( xRunningPrivileged );
#endif
}
/*-----------------------------------------------------------*/
void vPortExitCritical( void )
{
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
BaseType_t xRunningPrivileged;
xPortRaisePrivilege( xRunningPrivileged );
#endif
configASSERT( uxCriticalNesting );
uxCriticalNesting--;
@ -503,7 +522,9 @@ void vPortExitCritical( void )
portENABLE_INTERRUPTS();
}
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
vPortResetPrivilege( xRunningPrivileged );
#endif
}
/*-----------------------------------------------------------*/

View file

@ -56,6 +56,11 @@
#define portNVIC_SYSTICK_CLK ( 0 )
#endif
#ifndef configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS
#warning "configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS is not defined. We recommend defining it to 0 in FreeRTOSConfig.h for better security."
#define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS 1
#endif
/* Constants required to access and manipulate the NVIC. */
#define portNVIC_SYSTICK_CTRL_REG ( *( ( volatile uint32_t * ) 0xe000e010 ) )
#define portNVIC_SYSTICK_LOAD_REG ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@ -175,12 +180,20 @@ void vResetPrivilege( void ) __attribute__( ( naked ) );
/**
* @brief Enter critical section.
*/
void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
#else
void vPortEnterCritical( void ) PRIVILEGED_FUNCTION;
#endif
/**
* @brief Exit from critical section.
*/
void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
#else
void vPortExitCritical( void ) PRIVILEGED_FUNCTION;
#endif
/*-----------------------------------------------------------*/
/* Each task maintains its own interrupt status in the critical nesting
@ -516,20 +529,26 @@ void vPortEndScheduler( void )
void vPortEnterCritical( void )
{
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
BaseType_t xRunningPrivileged;
xPortRaisePrivilege( xRunningPrivileged );
#endif
portDISABLE_INTERRUPTS();
uxCriticalNesting++;
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
vPortResetPrivilege( xRunningPrivileged );
#endif
}
/*-----------------------------------------------------------*/
void vPortExitCritical( void )
{
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
BaseType_t xRunningPrivileged;
xPortRaisePrivilege( xRunningPrivileged );
#endif
configASSERT( uxCriticalNesting );
uxCriticalNesting--;
@ -539,7 +558,9 @@ void vPortExitCritical( void )
portENABLE_INTERRUPTS();
}
#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
vPortResetPrivilege( xRunningPrivileged );
#endif
}
/*-----------------------------------------------------------*/