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authorPaul Mundt <lethal@linux-sh.org>2006-12-08 03:41:43 -0500
committerPaul Mundt <lethal@linux-sh.org>2006-12-11 18:42:08 -0500
commitdc34d312c7b25d5d0f54c16d143a9526936e5d38 (patch)
tree3f409a98a130e688ffbe7787f18166b2a29f08a4 /arch/sh/kernel
parent1b73e6ae45d0353a062d7bea707757a235473cf9 (diff)
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>
Diffstat (limited to 'arch/sh/kernel')
-rw-r--r--arch/sh/kernel/process.c10
-rw-r--r--arch/sh/kernel/traps.c35
2 files changed, 45 insertions, 0 deletions
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,
498{ 498{
499 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 499 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
500 500
501 /* Rewind */
501 regs->pc -= 2; 502 regs->pc -= 2;
503
504#ifdef CONFIG_BUG
505 if (__kernel_text_address(instruction_pointer(regs))) {
506 u16 insn = *(u16 *)instruction_pointer(regs);
507 if (insn == TRAPA_BUG_OPCODE)
508 handle_BUG(regs);
509 }
510#endif
511
502 force_sig(SIGTRAP, current); 512 force_sig(SIGTRAP, current);
503} 513}
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 @@
19#include <linux/kallsyms.h> 19#include <linux/kallsyms.h>
20#include <linux/io.h> 20#include <linux/io.h>
21#include <linux/debug_locks.h> 21#include <linux/debug_locks.h>
22#include <linux/limits.h>
22#include <asm/system.h> 23#include <asm/system.h>
23#include <asm/uaccess.h> 24#include <asm/uaccess.h>
24 25
@@ -129,6 +130,40 @@ static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
129 return -EFAULT; 130 return -EFAULT;
130} 131}
131 132
133#ifdef CONFIG_BUG
134#ifdef CONFIG_DEBUG_BUGVERBOSE
135static inline void do_bug_verbose(struct pt_regs *regs)
136{
137 struct bug_frame f;
138 long len;
139
140 if (__copy_from_user(&f, (const void __user *)regs->pc,
141 sizeof(struct bug_frame)))
142 return;
143
144 len = __strnlen_user(f.file, PATH_MAX) - 1;
145 if (unlikely(len < 0 || len >= PATH_MAX))
146 f.file = "<bad filename>";
147 len = __strnlen_user(f.func, PATH_MAX) - 1;
148 if (unlikely(len < 0 || len >= PATH_MAX))
149 f.func = "<bad function>";
150
151 printk(KERN_ALERT "kernel BUG in %s() at %s:%d!\n",
152 f.func, f.file, f.line);
153}
154#else
155static inline void do_bug_verbose(struct pt_regs *regs)
156{
157}
158#endif /* CONFIG_DEBUG_BUGVERBOSE */
159#endif /* CONFIG_BUG */
160
161void handle_BUG(struct pt_regs *regs)
162{
163 do_bug_verbose(regs);
164 die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
165}
166
132/* 167/*
133 * handle an instruction that does an unaligned memory access by emulating the 168 * handle an instruction that does an unaligned memory access by emulating the
134 * desired behaviour 169 * desired behaviour