From: Paul Mundt Date: Fri, 8 Dec 2006 08:41:43 +0000 (+0900) Subject: sh: BUG() handling through trapa vector. X-Git-Tag: MMI-PSA29.97-13-9~45878^2~5^2~11 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=dc34d312c7b25d5d0f54c16d143a9526936e5d38;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git 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 --- 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 #include #include +#include #include #include @@ -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 = ""; + len = __strnlen_user(f.func, PATH_MAX) - 1; + if (unlikely(len < 0 || len >= PATH_MAX)) + f.func = ""; + + 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 diff --git a/include/asm-sh/bug.h b/include/asm-sh/bug.h index 1b4fc52a59e8..2f89dd06d0cd 100644 --- a/include/asm-sh/bug.h +++ b/include/asm-sh/bug.h @@ -1,19 +1,54 @@ #ifndef __ASM_SH_BUG_H #define __ASM_SH_BUG_H - #ifdef CONFIG_BUG -/* - * Tell the user there is some problem. - */ -#define BUG() do { \ - printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \ - *(volatile int *)0 = 0; \ + +struct bug_frame { + unsigned short opcode; + unsigned short line; + const char *file; + const char *func; +}; + +struct pt_regs; + +extern void handle_BUG(struct pt_regs *); + +#define TRAPA_BUG_OPCODE 0xc33e /* trapa #0x3e */ + +#ifdef CONFIG_DEBUG_BUGVERBOSE + +#define BUG() \ +do { \ + __asm__ __volatile__ ( \ + ".align 2\n\t" \ + ".short %O0\n\t" \ + ".short %O1\n\t" \ + ".long %O2\n\t" \ + ".long %O3\n\t" \ + : \ + : "n" (TRAPA_BUG_OPCODE), \ + "i" (__LINE__), "X" (__FILE__), \ + "X" (__FUNCTION__)); \ +} while (0) + +#else + +#define BUG() \ +do { \ + __asm__ __volatile__ ( \ + ".align 2\n\t" \ + ".short %O0\n\t" \ + : \ + : "n" (TRAPA_BUG_OPCODE)); \ } while (0) +#endif /* CONFIG_DEBUG_BUGVERBOSE */ + #define HAVE_ARCH_BUG -#endif + +#endif /* CONFIG_BUG */ #include -#endif +#endif /* __ASM_SH_BUG_H */