/*  Generic support for BUG()  This respects the following config options:  CONFIG_BUG - emit BUG traps.  Nothing happens without this.  CONFIG_GENERIC_BUG - enable this code.  CONFIG_DEBUG_BUGVERBOSE - emit full file+line information for each BUG  CONFIG_BUG and CONFIG_DEBUG_BUGVERBOSE are potentially user-settable  (though they're generally always on).  CONFIG_GENERIC_BUG is set by each architecture using this code.  To use this, your architecture must:  1. Set up the config options:     - Enable CONFIG_GENERIC_BUG if CONFIG_BUG  2. Implement BUG (and optionally BUG_ON, WARN, WARN_ON)     - Define HAVE_ARCH_BUG     - Implement BUG() to generate a faulting instruction     - NOTE: struct bug_entry does not have "file" or "line" entries       when CONFIG_DEBUG_BUGVERBOSE is not enabled, so you must generate       the values accordingly.  3. Implement the trap     - In the illegal instruction trap handler (typically), verify       that the fault was in kernel mode, and call report_bug()     - report_bug() will return whether it was a false alarm, a warning,       or an actual bug.     - You must implement the is_valid_bugaddr(bugaddr) callback which       returns true if the eip is a real kernel address, and it points       to the expected BUG trap instruction.    Jeremy Fitzhardinge <jeremy@goop.org> 2006 */#include <linux/list.h>#include <linux/module.h>#include <linux/kernel.h>#include <linux/bug.h>#include <linux/sched.h>extern const struct bug_entry __start___bug_table[], __stop___bug_table[];#ifdef CONFIG_MODULESstatic LIST_HEAD(module_bug_list);static const struct bug_entry *module_find_bug(unsigned long bugaddr){	struct module *mod;	list_for_each_entry(mod, &module_bug_list, bug_list) {		const struct bug_entry *bug = mod->bug_table;		unsigned i;		for (i = 0; i < mod->num_bugs; ++i, ++bug)			if (bugaddr == bug->bug_addr)				return bug;	}	return NULL;}int module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,			struct module *mod){	char *secstrings;	unsigned int i;	mod->bug_table = NULL;	mod->num_bugs = 0;	/* Find the __bug_table section, if present */	secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;	for (i = 1; i < hdr->e_shnum; i++) {		if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table"))			continue;		mod->bug_table = (void *) sechdrs[i].sh_addr;		mod->num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);		break;	}	/*	 * Strictly speaking this should have a spinlock to protect against	 * traversals, but since we only traverse on BUG()s, a spinlock	 * could potentially lead to deadlock and thus be counter-productive.	 */	list_add(&mod->bug_list, &module_bug_list);	return 0;}void module_bug_cleanup(struct module *mod){	list_del(&mod->bug_list);}#elsestatic inline const struct bug_entry *module_find_bug(unsigned long bugaddr){	return NULL;}#endifconst struct bug_entry *find_bug(unsigned long bugaddr){	const struct bug_entry *bug;	for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)		if (bugaddr == bug->bug_addr)			return bug;	return module_find_bug(bugaddr);}enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs){	const struct bug_entry *bug;	const char *file;	unsigned line, warning;	if (!is_valid_bugaddr(bugaddr))		return BUG_TRAP_TYPE_NONE;	bug = find_bug(bugaddr);	printk(KERN_EMERG "------------[ cut here ]------------\n");	file = NULL;	line = 0;	warning = 0;	if (bug) {#ifdef CONFIG_DEBUG_BUGVERBOSE		file = bug->file;		line = bug->line;#endif		warning = (bug->flags & BUGFLAG_WARNING) != 0;	}	if (warning) {		/* this is a WARN_ON rather than BUG/BUG_ON */		if (file)			printk(KERN_ERR "Badness at %s:%u\n",			       file, line);		else			printk(KERN_ERR "Badness at %p "			       "[verbose debug info unavailable]\n",			       (void *)bugaddr);		show_regs(regs);		add_taint(TAINT_WARN);		return BUG_TRAP_TYPE_WARN;	}	if (file)		printk(KERN_CRIT "kernel BUG at %s:%u!\n",		       file, line);	else		printk(KERN_CRIT "Kernel BUG at %p "		       "[verbose debug info unavailable]\n",		       (void *)bugaddr);	return BUG_TRAP_TYPE_BUG;}