Make sure SVCall uses highest exception priority

jefftenney · Oct 11, 2023 · 1498e04 · 1498e04
1 parent eade81b
commit 1498e04
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
@@ -42,6 +42,7 @@
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000e01c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
@@ -409,9 +410,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */