From: Paul Mundt <lethal@linux-sh.org>
Date: Mon, 19 May 2008 10:32:07 +0000 (+0900)
Subject: sh: Make is_valid_bugaddr() more intelligent on nommu.
X-Git-Tag: v2.6.26-rc4~119^2~1
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=9a33fc217d2248838d52f8ef214b1909073f3eb4;p=linux-2.6-omap-h63xx.git

sh: Make is_valid_bugaddr() more intelligent on nommu.

Currently is_valid_bugaddr() is true for anything >= PAGE_OFFSET, which
happens to be 0 on nommu configurations. Make this a bit smarter by just
reading in the opcode and comparing it against the trap type that we
already know. Follows the logic from avr32.

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

diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index a3bdc68ef02..438f1ebcc45 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -4,6 +4,7 @@
 #include <linux/kdebug.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
+#include <linux/uaccess.h>
 #include <asm/system.h>
 
 #ifdef CONFIG_BUG
@@ -21,7 +22,14 @@ static void handle_BUG(struct pt_regs *regs)
 
 int is_valid_bugaddr(unsigned long addr)
 {
-	return addr >= PAGE_OFFSET;
+	unsigned short opcode;
+
+	if (addr < PAGE_OFFSET)
+		return 0;
+	if (probe_kernel_address((u16 *)addr, opcode))
+		return 0;
+
+	return opcode == TRAPA_BUG_OPCODE;
 }
 #endif