Someone reported this bug to me. I think it is a valid one. Basically
trap_init() installs the vectors through kseg0 address and then flushes
icache. It is possible that the vectors are still in the data cache and not
written back to memory yet. If an exception happens it may get the corrupted
the vector value.
The following patch should fix it. I am not sure if I can use
flush_cache_range() to have potentially better performance.
--- linux/arch/mips/kernel/traps.c.orig Tue Jan 2 16:24:16 2001
+++ linux/arch/mips/kernel/traps.c Tue Jan 2 16:50:59 2001
@@ -767,7 +767,7 @@
panic("Unknown CPU type");
- flush_icache_range(KSEG0, KSEG0 + 0x200);
atomic_inc(&init_mm.mm_count); /* XXX UP? */
current->active_mm = &init_mm;