Fix incorrect return to physical address upon ITLB page fault exception

fallen · fallen · commit 0b65466c149b · 2012-06-14T23:23:19.000+02:00
When returning from itlb page fault we need to return to
the virtual address which caused the page fault and not the physical address.
We therefore overwrite the content of "ea" (exception address) register with
the result of rcsr ITLBMA.
diff --git a/software/mmu-bios/crt0.S b/software/mmu-bios/crt0.S
@@ -122,11 +122,12 @@ _dtlb_miss_exception_handler:
 _itlb_miss_exception_handler:
 	sw	(sp+0), ra
 	calli	.save_all
+	rcsr	r1, itlbma /* get virtual address which caused the page fault */
+	mv 	ea, r1 /* when returning from exception we branch back to that virtual address */
 	calli	itlb_miss_handler
 	bi	.restore_all_and_eret
 	nop
 	nop
-	nop
 
 macaddress:
 	.byte 0x10
