1 // SPDX-License-Identifier: GPL-2.0-only
3  * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
5  * Rewritten and vastly simplified by Rusty Russell for in-kernel
75 		len--;  in kallsyms_expand_symbol()
83 				maxlen--;  in kallsyms_expand_symbol()
105 	 * Get just the first code, look it up in the token table,  in kallsyms_get_symbol_type()
128 	 * Sequentially scan all the symbols up to the point we're searching  in get_symbol_offset()
137 		 * If MSB is 1, it is a "big" symbol, so we need to look into  in get_symbol_offset()
146 	return name - kallsyms_names;  in get_symbol_offset()
151 	/* values are unsigned offsets if --absolute-percpu is not in effect */  in kallsyms_sym_address()
159 	/* ...and negative offsets are relative to kallsyms_relative_base - 1 */  in kallsyms_sym_address()
160 	return kallsyms_relative_base - 1 - kallsyms_offsets[idx];  in kallsyms_sym_address()
183 	high = kallsyms_num_syms - 1;  in kallsyms_lookup_names()
186 		mid = low + (high - low) / 2;  in kallsyms_lookup_names()
194 			high = mid - 1;  in kallsyms_lookup_names()
200 		return -ESRCH;  in kallsyms_lookup_names()
204 		seq = get_symbol_seq(low - 1);  in kallsyms_lookup_names()
209 		low--;  in kallsyms_lookup_names()
215 		while (high < kallsyms_num_syms - 1) {  in kallsyms_lookup_names()
297 	while (high - low > 1) {  in get_symbol_pos()
298 		mid = low + (high - low) / 2;  in get_symbol_pos()
309 	while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))  in get_symbol_pos()
310 		--low;  in get_symbol_pos()
314 	/* Search for next non-aliased symbol. */  in get_symbol_pos()
333 		*symbolsize = symbol_end - symbol_start;  in get_symbol_pos()
335 		*offset = addr - symbol_start;  in get_symbol_pos()
363 	namebuf[KSYM_NAME_LEN - 1] = 0;  in kallsyms_lookup_buildid()
397  * - modname is set to NULL if it's in the kernel.
398  * - We guarantee that the returned name is valid until we reschedule even if.
400  * - We also guarantee that modname will be valid until rescheduled.
419 	symname[KSYM_NAME_LEN - 1] = '\0';  in lookup_symbol_name()
434 /* Look up a kernel symbol and return it in a text buffer. */
447 		return sprintf(buffer, "0x%lx", address - symbol_offset);  in __sprint_symbol()
449 	offset -= symbol_offset;  in __sprint_symbol()
472  * sprint_symbol - Look up a kernel symbol and return it in a text buffer
476  * This function looks up a kernel symbol with @address and stores its name,
489  * sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer
493  * This function looks up a kernel symbol with @address and stores its name,
506  * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
510  * This function looks up a kernel symbol with @address and stores its name
523  * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
529  * tail-call to the function marked "noreturn", gcc optimized out code after
530  * the call so that the stack-saved return address could point outside of the
538 	return __sprint_symbol(buffer, address, -1, 1, 0);  in sprint_backtrace()
542  * sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer
548  * tail-call to the function marked "noreturn", gcc optimized out code after
549  * the call so that the stack-saved return address could point outside of the
558 	return __sprint_symbol(buffer, address, -1, 1, 1);  in sprint_backtrace_build_id()
578 	int ret = module_get_kallsym(iter->pos - kallsyms_num_syms,  in get_ksymbol_mod()
579 				     &iter->value, &iter->type,  in get_ksymbol_mod()
580 				     iter->name, iter->module_name,  in get_ksymbol_mod()
581 				     &iter->exported);  in get_ksymbol_mod()
583 		iter->pos_mod_end = iter->pos;  in get_ksymbol_mod()
597 	int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,  in get_ksymbol_ftrace_mod()
598 					 &iter->value, &iter->type,  in get_ksymbol_ftrace_mod()
599 					 iter->name, iter->module_name,  in get_ksymbol_ftrace_mod()
600 					 &iter->exported);  in get_ksymbol_ftrace_mod()
602 		iter->pos_ftrace_mod_end = iter->pos;  in get_ksymbol_ftrace_mod()
613 	strscpy(iter->module_name, "bpf", MODULE_NAME_LEN);  in get_ksymbol_bpf()
614 	iter->exported = 0;  in get_ksymbol_bpf()
615 	ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,  in get_ksymbol_bpf()
616 			      &iter->value, &iter->type,  in get_ksymbol_bpf()
617 			      iter->name);  in get_ksymbol_bpf()
619 		iter->pos_bpf_end = iter->pos;  in get_ksymbol_bpf()
633 	strscpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);  in get_ksymbol_kprobe()
634 	iter->exported = 0;  in get_ksymbol_kprobe()
635 	return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,  in get_ksymbol_kprobe()
636 				  &iter->value, &iter->type,  in get_ksymbol_kprobe()
637 				  iter->name) < 0 ? 0 : 1;  in get_ksymbol_kprobe()
643 	unsigned off = iter->nameoff;  in get_ksymbol_core()
645 	iter->module_name[0] = '\0';  in get_ksymbol_core()
646 	iter->value = kallsyms_sym_address(iter->pos);  in get_ksymbol_core()
648 	iter->type = kallsyms_get_symbol_type(off);  in get_ksymbol_core()
650 	off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));  in get_ksymbol_core()
652 	return off - iter->nameoff;  in get_ksymbol_core()
657 	iter->name[0] = '\0';  in reset_iter()
658 	iter->nameoff = get_symbol_offset(new_pos);  in reset_iter()
659 	iter->pos = new_pos;  in reset_iter()
661 		iter->pos_mod_end = 0;  in reset_iter()
662 		iter->pos_ftrace_mod_end = 0;  in reset_iter()
663 		iter->pos_bpf_end = 0;  in reset_iter()
669  * in iter->pos_..._end as each section is added, and so can be used to
674 	iter->pos = pos;  in update_iter_mod()
676 	if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&  in update_iter_mod()
680 	if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&  in update_iter_mod()
684 	if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) &&  in update_iter_mod()
699 	if (pos != iter->pos)  in update_iter()
702 	iter->nameoff += get_ksymbol_core(iter);  in update_iter()
703 	iter->pos++;  in update_iter()
712 	if (!update_iter(m->private, *pos))  in s_next()
719 	if (!update_iter(m->private, *pos))  in s_start()
721 	return m->private;  in s_start()
731 	struct kallsym_iter *iter = m->private;  in s_show()
734 	if (!iter->name[0])  in s_show()
737 	value = iter->show_value ? (void *)iter->value : NULL;  in s_show()
739 	if (iter->module_name[0]) {  in s_show()
746 		type = iter->exported ? toupper(iter->type) :  in s_show()
747 					tolower(iter->type);  in s_show()
749 			   type, iter->name, iter->module_name);  in s_show()
752 			   iter->type, iter->name);  in s_show()
782 	ctx.ksym = m ? m->private : NULL;  in ksym_prog_seq_show()
815 	iter->show_value = kallsyms_show_value(current_cred());  in bpf_iter_ksym_init()
856 	 * We keep iterator in m->private, since normal case is to  in kallsyms_open()
863 		return -ENOMEM;  in kallsyms_open()
870 	iter->show_value = kallsyms_show_value(file->f_cred);  in kallsyms_open()