// SPDX-License-Identifier: GPL-2.0-or-later/* *  fw_tables.c - Parsing support for ACPI and ACPI-like tables provided by *                platform or device firmware * *  Copyright (C) 2001 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> *  Copyright (C) 2023 Intel Corp. */#include <linux/errno.h>#include <linux/acpi.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/string.h>#include <linux/types.h> enum acpi_subtable_type {	ACPI_SUBTABLE_COMMON,	ACPI_SUBTABLE_HMAT,	ACPI_SUBTABLE_PRMT,	ACPI_SUBTABLE_CEDT,}; struct acpi_subtable_entry {	union acpi_subtable_headers *hdr;	enum acpi_subtable_type type;}; static unsigned long __init_or_acpilibacpi_get_entry_type(struct acpi_subtable_entry *entry){	switch (entry->type) {	case ACPI_SUBTABLE_COMMON:		return entry->hdr->common.type;	case ACPI_SUBTABLE_HMAT:		return entry->hdr->hmat.type;	case ACPI_SUBTABLE_PRMT:		return 0;	case ACPI_SUBTABLE_CEDT:		return entry->hdr->cedt.type;	}	return 0;} static unsigned long __init_or_acpilibacpi_get_entry_length(struct acpi_subtable_entry *entry){	switch (entry->type) {	case ACPI_SUBTABLE_COMMON:		return entry->hdr->common.length;	case ACPI_SUBTABLE_HMAT:		return entry->hdr->hmat.length;	case ACPI_SUBTABLE_PRMT:		return entry->hdr->prmt.length;	case ACPI_SUBTABLE_CEDT:		return entry->hdr->cedt.length;	}	return 0;} static unsigned long __init_or_acpilibacpi_get_subtable_header_length(struct acpi_subtable_entry *entry){	switch (entry->type) {	case ACPI_SUBTABLE_COMMON:		return sizeof(entry->hdr->common);	case ACPI_SUBTABLE_HMAT:		return sizeof(entry->hdr->hmat);	case ACPI_SUBTABLE_PRMT:		return sizeof(entry->hdr->prmt);	case ACPI_SUBTABLE_CEDT:		return sizeof(entry->hdr->cedt);	}	return 0;} static enum acpi_subtable_type __init_or_acpilibacpi_get_subtable_type(char *id){	if (strncmp(id, ACPI_SIG_HMAT, 4) == 0)		return ACPI_SUBTABLE_HMAT;	if (strncmp(id, ACPI_SIG_PRMT, 4) == 0)		return ACPI_SUBTABLE_PRMT;	if (strncmp(id, ACPI_SIG_CEDT, 4) == 0)		return ACPI_SUBTABLE_CEDT;	return ACPI_SUBTABLE_COMMON;} static __init_or_acpilib bool has_handler(struct acpi_subtable_proc *proc){	return proc->handler || proc->handler_arg;} static __init_or_acpilib int call_handler(struct acpi_subtable_proc *proc,					  union acpi_subtable_headers *hdr,					  unsigned long end){	if (proc->handler)		return proc->handler(hdr, end);	if (proc->handler_arg)		return proc->handler_arg(hdr, proc->arg, end);	return -EINVAL;} /** * acpi_parse_entries_array - for each proc_num find a suitable subtable * * @id: table id (for debugging purposes) * @table_size: size of the root table * @table_header: where does the table start? * @proc: array of acpi_subtable_proc struct containing entry id *        and associated handler with it * @proc_num: how big proc is? * @max_entries: how many entries can we process? * * For each proc_num find a subtable with proc->id and run proc->handler * on it. Assumption is that there's only single handler for particular * entry id. * * The table_size is not the size of the complete ACPI table (the length * field in the header struct), but only the size of the root table; i.e., * the offset from the very first byte of the complete ACPI table, to the * first byte of the very first subtable. * * On success returns sum of all matching entries for all proc handlers. * Otherwise, -ENODEV or -EINVAL is returned. */int __init_or_acpilibacpi_parse_entries_array(char *id, unsigned long table_size,			 struct acpi_table_header *table_header,			 struct acpi_subtable_proc *proc,			 int proc_num, unsigned int max_entries){	unsigned long table_end, subtable_len, entry_len;	struct acpi_subtable_entry entry;	int count = 0;	int errs = 0;	int i; 	table_end = (unsigned long)table_header + table_header->length; 	/* Parse all entries looking for a match. */ 	entry.type = acpi_get_subtable_type(id);	entry.hdr = (union acpi_subtable_headers *)	    ((unsigned long)table_header + table_size);	subtable_len = acpi_get_subtable_header_length(&entry); 	while (((unsigned long)entry.hdr) + subtable_len  < table_end) {		if (max_entries && count >= max_entries)			break; 		for (i = 0; i < proc_num; i++) {			if (acpi_get_entry_type(&entry) != proc[i].id)				continue;			if (!has_handler(&proc[i]) ||			    (!errs &&			     call_handler(&proc[i], entry.hdr, table_end))) {				errs++;				continue;			} 			proc[i].count++;			break;		}		if (i != proc_num)			count++; 		/*		 * If entry->length is 0, break from this loop to avoid		 * infinite loop.		 */		entry_len = acpi_get_entry_length(&entry);		if (entry_len == 0) {			pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, proc->id);			return -EINVAL;		} 		entry.hdr = (union acpi_subtable_headers *)		    ((unsigned long)entry.hdr + entry_len);	} 	if (max_entries && count > max_entries) {		pr_warn("[%4.4s:0x%02x] found the maximum %i entries\n",			id, proc->id, count);	} 	return errs ? -EINVAL : count;}