From dc34d312c7b25d5d0f54c16d143a9526936e5d38 Mon Sep 17 00:00:00 2001
From: Paul Mundt <lethal@linux-sh.org>
Date: Fri, 8 Dec 2006 17:41:43 +0900
Subject: 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>
---
arch/sh/kernel/process.c | 10 ++++++++++
arch/sh/kernel/traps.c | 35 +++++++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+)
(limited to 'arch/sh')
diff --git a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
index f3e2631be144..7347f6afa030 100644
--- a/arch/sh/kernel/process.c
+++ b/arch/sh/kernel/process.c
@@ -498,6 +498,16 @@ asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
{
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);
}
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 3762d9dc2046..ec110157992d 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -19,6 +19,7 @@
#include <linux/kallsyms.h>
#include <linux/io.h>
#include <linux/debug_locks.h>
+#include <linux/limits.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -129,6 +130,40 @@ static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
return -EFAULT;
}
+#ifdef CONFIG_BUG
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+static inline void do_bug_verbose(struct pt_regs *regs)
+{
+ struct bug_frame f;
+ long len;
+
+ if (__copy_from_user(&f, (const void __user *)regs->pc,
+ sizeof(struct bug_frame)))
+ return;
+
+ len = __strnlen_user(f.file, PATH_MAX) - 1;
+ if (unlikely(len < 0 || len >= PATH_MAX))
+ f.file = "<bad filename>";
+ len = __strnlen_user(f.func, PATH_MAX) - 1;
+ if (unlikely(len < 0 || len >= PATH_MAX))
+ f.func = "<bad function>";
+
+ printk(KERN_ALERT "kernel BUG in %s() at %s:%d!\n",
+ f.func, f.file, f.line);
+}
+#else
+static inline void do_bug_verbose(struct pt_regs *regs)
+{
+}
+#endif /* CONFIG_DEBUG_BUGVERBOSE */
+#endif /* CONFIG_BUG */
+
+void handle_BUG(struct pt_regs *regs)
+{
+ do_bug_verbose(regs);
+ die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
+}
+
/*
* handle an instruction that does an unaligned memory access by emulating the
* desired behaviour
--
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