riscv: Fixes GDB backtrace of interrupted threads
Save missed SP value on stack
@@ -201,6 +201,17 @@ _interrupt_handler:
save_general_regs
save_mepc
+ /* Though it is not necessary we save GP and SP here.
+ * SP is necessary to help GDB to properly unwind
+ * the backtrace of threads preempted by interrupts (OS tick etc.).
+ * GP is saved just to have its proper value in GDB. */
+ /* As gp register is not saved by the macro, save it here */
+ sw gp, RV_STK_GP(sp)
+ /* Same goes for the SP value before trapping */
+ addi t0, sp, CONTEXT_SIZE /* restore sp with the value when interrupt happened */
+ /* Save SP */
+ sw t0, RV_STK_SP(sp)
+
/* Before doing anythig preserve the stack pointer */
/* It will be saved in current TCB, if needed */
mv a0, sp
