sh: BUG() handling through trapa vector.
Previously we haven't been doing anything with verbose BUG() reporting,
and we've been relying on the oops path for handling BUG()'s, which is
rather sub-optimal.
This switches BUG handling to use a fixed trapa vector (#0x3e) where we
construct a small bug frame post trapa instruction to get the context
right. This also makes it trivial to wire up a DIE_BUG for the atomic
die chain, which we couldn't really do before.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
index f3e2631..7347f6a 100644
--- a/arch/sh/kernel/process.c
+++ b/arch/sh/kernel/process.c
@@ -498,6 +498,16 @@
{
struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+ /* Rewind */
regs->pc -= 2;
+
+#ifdef CONFIG_BUG
+ if (__kernel_text_address(instruction_pointer(regs))) {
+ u16 insn = *(u16 *)instruction_pointer(regs);
+ if (insn == TRAPA_BUG_OPCODE)
+ handle_BUG(regs);
+ }
+#endif
+
force_sig(SIGTRAP, current);
}