sh: unwinder: Use a special bug flag for unwinder traps.

This simplifies the unwinder trap handling, dropping the use of the
special trapa vector and simply piggybacking on top of the BUG support. A
new BUGFLAG_UNWINDER is added for flagging the unwinder fault, before
continuing on with regular BUG dispatch.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 17 insertions, 4 deletions

diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 881b9a32b7de..f69bd968fcca 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -5,18 +5,32 @@
 #include <linux/signal.h>
 #include <linux/sched.h>
 #include <linux/uaccess.h>
+#include <asm/unwinder.h>
 #include <asm/system.h>
 
 #ifdef CONFIG_BUG
 void handle_BUG(struct pt_regs *regs)
 {
+	const struct bug_entry *bug;
+	unsigned long bugaddr = regs->pc;
 	enum bug_trap_type tt;
-	tt = report_bug(regs->pc, regs);
+
+	if (!is_valid_bugaddr(bugaddr))
+		goto invalid;
+
+	bug = find_bug(bugaddr);
+
+	/* Switch unwinders when unwind_stack() is called */
+	if (bug->flags & BUGFLAG_UNWINDER)
+		unwinder_faulted = 1;
+
+	tt = report_bug(bugaddr, regs);
 	if (tt == BUG_TRAP_TYPE_WARN) {
-		regs->pc += instruction_size(regs->pc);
+		regs->pc += instruction_size(bugaddr);
 		return;
 	}
 
+invalid:
 	die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
 }
 
@@ -28,8 +42,7 @@ int is_valid_bugaddr(unsigned long addr)
 		return 0;
 	if (probe_kernel_address((insn_size_t *)addr, opcode))
 		return 0;
-
-	if (opcode == TRAPA_BUG_OPCODE || opcode == TRAPA_UNWINDER_BUG_OPCODE)
+	if (opcode == TRAPA_BUG_OPCODE)
 		return 1;
 
 	return 0;