]> git.sur5r.net Git - freertos/blobdiff - FreeRTOS/Source/portable/GCC/ARM_CM3/port.c
Add additional memory barriers into ARM GCC asm code to ensure no re-ordering across...
[freertos] / FreeRTOS / Source / portable / GCC / ARM_CM3 / port.c
index e72fc3ec48eb9b26c05cdf2a0a4013f6be438a8e..ba512f0b42ce9b8c35bca32440f68a27de7d0dce 100644 (file)
@@ -1,5 +1,5 @@
 /*\r
-    FreeRTOS V9.0.0rc2 - Copyright (C) 2016 Real Time Engineers Ltd.\r
+    FreeRTOS V9.0.1 - Copyright (C) 2017 Real Time Engineers Ltd.\r
     All rights reserved\r
 \r
     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.\r
@@ -324,6 +324,24 @@ BaseType_t xPortStartScheduler( void )
                        ucMaxPriorityValue <<= ( uint8_t ) 0x01;\r
                }\r
 \r
+               #ifdef __NVIC_PRIO_BITS\r
+               {\r
+                       /* Check the CMSIS configuration that defines the number of\r
+                       priority bits matches the number of priority bits actually queried\r
+                       from the hardware. */\r
+                       configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == __NVIC_PRIO_BITS );\r
+               }\r
+               #endif\r
+\r
+               #ifdef configPRIO_BITS\r
+               {\r
+                       /* Check the FreeRTOS configuration that defines the number of\r
+                       priority bits matches the number of priority bits actually queried\r
+                       from the hardware. */\r
+                       configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == configPRIO_BITS );\r
+               }\r
+               #endif\r
+\r
                /* Shift the priority group value back to its position within the AIRCR\r
                register. */\r
                ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;\r
@@ -418,7 +436,7 @@ void xPortPendSVHandler( void )
        "       mov r0, #0                                                      \n"\r
        "       msr basepri, r0                                         \n"\r
        "       ldmia sp!, {r3, r14}                            \n"\r
-       "                                                                               \n"     /* Restore the context, including the critical nesting count. */\r
+       "                                                                               \n" /* Restore the context, including the critical nesting count. */\r
        "       ldr r1, [r3]                                            \n"\r
        "       ldr r0, [r1]                                            \n" /* The first item in pxCurrentTCB is the task top of stack. */\r
        "       ldmia r0!, {r4-r11}                                     \n" /* Pop the registers. */\r
@@ -457,7 +475,7 @@ void xPortSysTickHandler( void )
 \r
        __attribute__((weak)) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )\r
        {\r
-       uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL;\r
+       uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements;\r
        TickType_t xModifiableIdleTime;\r
 \r
                /* Make sure the SysTick reload value does not overflow the counter. */\r
@@ -483,7 +501,7 @@ void xPortSysTickHandler( void )
 \r
                /* Enter a critical section but don't use the taskENTER_CRITICAL()\r
                method as that will mask interrupts that should exit sleep mode. */\r
-               __asm volatile( "cpsid i" );\r
+               __asm volatile( "cpsid i" ::: "memory" );\r
                __asm volatile( "dsb" );\r
                __asm volatile( "isb" );\r
 \r
@@ -504,7 +522,7 @@ void xPortSysTickHandler( void )
 \r
                        /* Re-enable interrupts - see comments above the cpsid instruction()\r
                        above. */\r
-                       __asm volatile( "cpsie i" );\r
+                       __asm volatile( "cpsie i" ::: "memory" );\r
                }\r
                else\r
                {\r
@@ -527,24 +545,27 @@ void xPortSysTickHandler( void )
                        configPRE_SLEEP_PROCESSING( xModifiableIdleTime );\r
                        if( xModifiableIdleTime > 0 )\r
                        {\r
-                               __asm volatile( "dsb" );\r
+                               __asm volatile( "dsb" ::: "memory" );\r
                                __asm volatile( "wfi" );\r
                                __asm volatile( "isb" );\r
                        }\r
                        configPOST_SLEEP_PROCESSING( xExpectedIdleTime );\r
 \r
-                       /* Stop SysTick.  Again, the time the SysTick is stopped for is\r
-                       accounted for as best it can be, but using the tickless mode will\r
-                       inevitably result in some tiny drift of the time maintained by the\r
-                       kernel with respect to calendar time. */\r
-                       ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG;\r
-                       portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT );\r
-\r
                        /* Re-enable interrupts - see comments above the cpsid instruction()\r
                        above. */\r
-                       __asm volatile( "cpsie i" );\r
-\r
-                       if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )\r
+                       __asm volatile( "cpsie i" ::: "memory" );\r
+\r
+                       /* Disable the SysTick clock without reading the\r
+                       portNVIC_SYSTICK_CTRL_REG register to ensure the\r
+                       portNVIC_SYSTICK_COUNT_FLAG_BIT is not cleared if it is set. */\r
+                       portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT );\r
+\r
+                       /* Determine if the SysTick clock has already counted to zero and\r
+                       been set back to the current reload value (the reload back being\r
+                       correct for the entire expected idle time) or if the SysTick is yet\r
+                       to count to zero (in which case an interrupt other than the SysTick\r
+                       must have brought the system out of sleep mode). */\r
+                       if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )\r
                        {\r
                                uint32_t ulCalculatedLoadValue;\r
 \r
@@ -622,6 +643,10 @@ __attribute__(( weak )) void vPortSetupTimerInterrupt( void )
        }\r
        #endif /* configUSE_TICKLESS_IDLE */\r
 \r
+       /* Stop and clear the SysTick. */\r
+       portNVIC_SYSTICK_CTRL_REG = 0UL;\r
+       portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;\r
+\r
        /* Configure SysTick to interrupt at the requested rate. */\r
        portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;\r
        portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );\r
@@ -636,7 +661,7 @@ __attribute__(( weak )) void vPortSetupTimerInterrupt( void )
        uint8_t ucCurrentPriority;\r
 \r
                /* Obtain the number of the currently executing interrupt. */\r
-               __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) );\r
+               __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) :: "memory" );\r
 \r
                /* Is the interrupt number a user defined interrupt? */\r
                if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER )\r