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()
175 	high = kallsyms_num_syms - 1;  in kallsyms_lookup_names()
178 		mid = low + (high - low) / 2;  in kallsyms_lookup_names()
186 			high = mid - 1;  in kallsyms_lookup_names()
192 		return -ESRCH;  in kallsyms_lookup_names()
196 		seq = get_symbol_seq(low - 1);  in kallsyms_lookup_names()
201 		low--;  in kallsyms_lookup_names()
207 		while (high < kallsyms_num_syms - 1) {  in kallsyms_lookup_names()
289 	while (high - low > 1) {  in get_symbol_pos()
290 		mid = low + (high - low) / 2;  in get_symbol_pos()
301 	while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))  in get_symbol_pos()
302 		--low;  in get_symbol_pos()
306 	/* Search for next non-aliased symbol. */  in get_symbol_pos()
325 		*symbolsize = symbol_end - symbol_start;  in get_symbol_pos()
327 		*offset = addr - symbol_start;  in get_symbol_pos()
355 	namebuf[KSYM_NAME_LEN - 1] = 0;  in kallsyms_lookup_buildid()
389  * - modname is set to NULL if it's in the kernel.
390  * - We guarantee that the returned name is valid until we reschedule even if.
392  * - We also guarantee that modname will be valid until rescheduled.
411 	symname[KSYM_NAME_LEN - 1] = '\0';  in lookup_symbol_name()
426 /* Look up a kernel symbol and return it in a text buffer. */
439 		return sprintf(buffer, "0x%lx", address - symbol_offset);  in __sprint_symbol()
441 	offset -= symbol_offset;  in __sprint_symbol()
464  * sprint_symbol - Look up a kernel symbol and return it in a text buffer
468  * This function looks up a kernel symbol with @address and stores its name,
481  * sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer
485  * This function looks up a kernel symbol with @address and stores its name,
498  * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
502  * This function looks up a kernel symbol with @address and stores its name
515  * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
521  * tail-call to the function marked "noreturn", gcc optimized out code after
522  * the call so that the stack-saved return address could point outside of the
530 	return __sprint_symbol(buffer, address, -1, 1, 0);  in sprint_backtrace()
534  * sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer
540  * tail-call to the function marked "noreturn", gcc optimized out code after
541  * the call so that the stack-saved return address could point outside of the
550 	return __sprint_symbol(buffer, address, -1, 1, 1);  in sprint_backtrace_build_id()
570 	int ret = module_get_kallsym(iter->pos - kallsyms_num_syms,  in get_ksymbol_mod()
571 				     &iter->value, &iter->type,  in get_ksymbol_mod()
572 				     iter->name, iter->module_name,  in get_ksymbol_mod()
573 				     &iter->exported);  in get_ksymbol_mod()
575 		iter->pos_mod_end = iter->pos;  in get_ksymbol_mod()
589 	int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,  in get_ksymbol_ftrace_mod()
590 					 &iter->value, &iter->type,  in get_ksymbol_ftrace_mod()
591 					 iter->name, iter->module_name,  in get_ksymbol_ftrace_mod()
592 					 &iter->exported);  in get_ksymbol_ftrace_mod()
594 		iter->pos_ftrace_mod_end = iter->pos;  in get_ksymbol_ftrace_mod()
605 	strscpy(iter->module_name, "bpf", MODULE_NAME_LEN);  in get_ksymbol_bpf()
606 	iter->exported = 0;  in get_ksymbol_bpf()
607 	ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,  in get_ksymbol_bpf()
608 			      &iter->value, &iter->type,  in get_ksymbol_bpf()
609 			      iter->name);  in get_ksymbol_bpf()
611 		iter->pos_bpf_end = iter->pos;  in get_ksymbol_bpf()
625 	strscpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);  in get_ksymbol_kprobe()
626 	iter->exported = 0;  in get_ksymbol_kprobe()
627 	return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,  in get_ksymbol_kprobe()
628 				  &iter->value, &iter->type,  in get_ksymbol_kprobe()
629 				  iter->name) < 0 ? 0 : 1;  in get_ksymbol_kprobe()
635 	unsigned off = iter->nameoff;  in get_ksymbol_core()
637 	iter->module_name[0] = '\0';  in get_ksymbol_core()
638 	iter->value = kallsyms_sym_address(iter->pos);  in get_ksymbol_core()
640 	iter->type = kallsyms_get_symbol_type(off);  in get_ksymbol_core()
642 	off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));  in get_ksymbol_core()
644 	return off - iter->nameoff;  in get_ksymbol_core()
649 	iter->name[0] = '\0';  in reset_iter()
650 	iter->nameoff = get_symbol_offset(new_pos);  in reset_iter()
651 	iter->pos = new_pos;  in reset_iter()
653 		iter->pos_mod_end = 0;  in reset_iter()
654 		iter->pos_ftrace_mod_end = 0;  in reset_iter()
655 		iter->pos_bpf_end = 0;  in reset_iter()
661  * in iter->pos_..._end as each section is added, and so can be used to
666 	iter->pos = pos;  in update_iter_mod()
668 	if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&  in update_iter_mod()
672 	if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&  in update_iter_mod()
676 	if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) &&  in update_iter_mod()
691 	if (pos != iter->pos)  in update_iter()
694 	iter->nameoff += get_ksymbol_core(iter);  in update_iter()
695 	iter->pos++;  in update_iter()
704 	if (!update_iter(m->private, *pos))  in s_next()
711 	if (!update_iter(m->private, *pos))  in s_start()
713 	return m->private;  in s_start()
723 	struct kallsym_iter *iter = m->private;  in s_show()
726 	if (!iter->name[0])  in s_show()
729 	value = iter->show_value ? (void *)iter->value : NULL;  in s_show()
731 	if (iter->module_name[0]) {  in s_show()
738 		type = iter->exported ? toupper(iter->type) :  in s_show()
739 					tolower(iter->type);  in s_show()
741 			   type, iter->name, iter->module_name);  in s_show()
744 			   iter->type, iter->name);  in s_show()
774 	ctx.ksym = m ? m->private : NULL;  in ksym_prog_seq_show()
807 	iter->show_value = kallsyms_show_value(current_cred());  in bpf_iter_ksym_init()
847 	 * We keep iterator in m->private, since normal case is to  in kallsyms_open()
854 		return -ENOMEM;  in kallsyms_open()
861 	iter->show_value = kallsyms_show_value(file->f_cred);  in kallsyms_open()