Re: [U-Boot] [PATCH v5 16/23] Adjust board_f.c for ppc

12 Feb 2013


      On 02/08/2013 09:12:12 AM, Simon Glass wrote:
...
#ifndef CONFIG_SPL_BUILD
 static int reserve_stacks(void)
 {
+#ifdef CONFIG_PPC

ulong *s;

+#endif

/* setup stack pointer for exceptions */
 gd->dest_addr_sp -= 16;
 gd->dest_addr_sp &= ~0xf;

@@ -398,6 +532,14 @@ static int reserve_stacks(void)
   /* leave 3 words for abort-stack, plus 1 for alignment */
   gd->dest_addr_sp -= 16;
+#ifdef CONFIG_PPC

/* Clear initial stack frame */
s = (ulong *) gd->dest_addr_sp;
*s = 0; /* Terminate back chain */
*++s = 0; /* NULL return address */
gd->dest_addr_sp = (ulong) s;

+#endif



PPC ABI requires 16-byte stack alignment, which would be broken by the  
CONFIG_USE_IRQ section (which even still has an "ARM ABI" comment).
I think this entire function should be kept in arch code.  Stack layout  
is inherently architecture/ABI specific.  Some architectures even have  
a stack that grows upward (not sure if any such are supported by  
U-Boot).
-Scott

    

Scott Wood