1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * fw_tables.c - Parsing support for ACPI and ACPI-like tables provided by 4 * platform or device firmware 5 * 6 * Copyright (C) 2001 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> 7 * Copyright (C) 2023 Intel Corp. 8 */ 9 #include <linux/errno.h> 10 #include <linux/acpi.h> 11 #include <linux/init.h> 12 #include <linux/kernel.h> 13 #include <linux/string.h> 14 #include <linux/types.h> 15 #include <linux/fw_table.h> 16 17 enum acpi_subtable_type { 18 ACPI_SUBTABLE_COMMON, 19 ACPI_SUBTABLE_HMAT, 20 ACPI_SUBTABLE_PRMT, 21 ACPI_SUBTABLE_CEDT, 22 CDAT_SUBTABLE, 23 }; 24 25 struct acpi_subtable_entry { 26 union acpi_subtable_headers *hdr; 27 enum acpi_subtable_type type; 28 }; 29 30 static unsigned long __init_or_fwtbl_lib 31 acpi_get_entry_type(struct acpi_subtable_entry *entry) 32 { 33 switch (entry->type) { 34 case ACPI_SUBTABLE_COMMON: 35 return entry->hdr->common.type; 36 case ACPI_SUBTABLE_HMAT: 37 return entry->hdr->hmat.type; 38 case ACPI_SUBTABLE_PRMT: 39 return 0; 40 case ACPI_SUBTABLE_CEDT: 41 return entry->hdr->cedt.type; 42 case CDAT_SUBTABLE: 43 return entry->hdr->cdat.type; 44 } 45 return 0; 46 } 47 48 static unsigned long __init_or_fwtbl_lib 49 acpi_get_entry_length(struct acpi_subtable_entry *entry) 50 { 51 switch (entry->type) { 52 case ACPI_SUBTABLE_COMMON: 53 return entry->hdr->common.length; 54 case ACPI_SUBTABLE_HMAT: 55 return entry->hdr->hmat.length; 56 case ACPI_SUBTABLE_PRMT: 57 return entry->hdr->prmt.length; 58 case ACPI_SUBTABLE_CEDT: 59 return entry->hdr->cedt.length; 60 case CDAT_SUBTABLE: { 61 __le16 length = (__force __le16)entry->hdr->cdat.length; 62 63 return le16_to_cpu(length); 64 } 65 } 66 return 0; 67 } 68 69 static unsigned long __init_or_fwtbl_lib 70 acpi_get_subtable_header_length(struct acpi_subtable_entry *entry) 71 { 72 switch (entry->type) { 73 case ACPI_SUBTABLE_COMMON: 74 return sizeof(entry->hdr->common); 75 case ACPI_SUBTABLE_HMAT: 76 return sizeof(entry->hdr->hmat); 77 case ACPI_SUBTABLE_PRMT: 78 return sizeof(entry->hdr->prmt); 79 case ACPI_SUBTABLE_CEDT: 80 return sizeof(entry->hdr->cedt); 81 case CDAT_SUBTABLE: 82 return sizeof(entry->hdr->cdat); 83 } 84 return 0; 85 } 86 87 static enum acpi_subtable_type __init_or_fwtbl_lib 88 acpi_get_subtable_type(char *id) 89 { 90 if (strncmp(id, ACPI_SIG_HMAT, 4) == 0) 91 return ACPI_SUBTABLE_HMAT; 92 if (strncmp(id, ACPI_SIG_PRMT, 4) == 0) 93 return ACPI_SUBTABLE_PRMT; 94 if (strncmp(id, ACPI_SIG_CEDT, 4) == 0) 95 return ACPI_SUBTABLE_CEDT; 96 if (strncmp(id, ACPI_SIG_CDAT, 4) == 0) 97 return CDAT_SUBTABLE; 98 return ACPI_SUBTABLE_COMMON; 99 } 100 101 static unsigned long __init_or_fwtbl_lib 102 acpi_table_get_length(enum acpi_subtable_type type, 103 union fw_table_header *header) 104 { 105 if (type == CDAT_SUBTABLE) { 106 __le32 length = (__force __le32)header->cdat.length; 107 108 return le32_to_cpu(length); 109 } 110 111 return header->acpi.length; 112 } 113 114 static __init_or_fwtbl_lib int call_handler(struct acpi_subtable_proc *proc, 115 union acpi_subtable_headers *hdr, 116 unsigned long end) 117 { 118 if (proc->handler) 119 return proc->handler(hdr, end); 120 if (proc->handler_arg) 121 return proc->handler_arg(hdr, proc->arg, end); 122 return -EINVAL; 123 } 124 125 /** 126 * acpi_parse_entries_array - for each proc_num find a suitable subtable 127 * 128 * @id: table id (for debugging purposes) 129 * @table_size: size of the root table 130 * @max_length: maximum size of the table (ignore if 0) 131 * @table_header: where does the table start? 132 * @proc: array of acpi_subtable_proc struct containing entry id 133 * and associated handler with it 134 * @proc_num: how big proc is? 135 * @max_entries: how many entries can we process? 136 * 137 * For each proc_num find a subtable with proc->id and run proc->handler 138 * on it. Assumption is that there's only single handler for particular 139 * entry id. 140 * 141 * The table_size is not the size of the complete ACPI table (the length 142 * field in the header struct), but only the size of the root table; i.e., 143 * the offset from the very first byte of the complete ACPI table, to the 144 * first byte of the very first subtable. 145 * 146 * On success returns sum of all matching entries for all proc handlers. 147 * Otherwise, -ENODEV or -EINVAL is returned. 148 */ 149 int __init_or_fwtbl_lib 150 acpi_parse_entries_array(char *id, unsigned long table_size, 151 union fw_table_header *table_header, 152 unsigned long max_length, 153 struct acpi_subtable_proc *proc, 154 int proc_num, unsigned int max_entries) 155 { 156 unsigned long table_len, table_end, subtable_len, entry_len; 157 struct acpi_subtable_entry entry; 158 enum acpi_subtable_type type; 159 int count = 0; 160 int i; 161 162 type = acpi_get_subtable_type(id); 163 table_len = acpi_table_get_length(type, table_header); 164 if (max_length && max_length < table_len) 165 table_len = max_length; 166 table_end = (unsigned long)table_header + table_len; 167 168 /* Parse all entries looking for a match. */ 169 170 entry.type = type; 171 entry.hdr = (union acpi_subtable_headers *) 172 ((unsigned long)table_header + table_size); 173 subtable_len = acpi_get_subtable_header_length(&entry); 174 175 while (((unsigned long)entry.hdr) + subtable_len < table_end) { 176 for (i = 0; i < proc_num; i++) { 177 if (acpi_get_entry_type(&entry) != proc[i].id) 178 continue; 179 180 if (!max_entries || count < max_entries) 181 if (call_handler(&proc[i], entry.hdr, table_end)) 182 return -EINVAL; 183 184 proc[i].count++; 185 count++; 186 break; 187 } 188 189 /* 190 * If entry->length is 0, break from this loop to avoid 191 * infinite loop. 192 */ 193 entry_len = acpi_get_entry_length(&entry); 194 if (entry_len == 0) { 195 pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, proc->id); 196 return -EINVAL; 197 } 198 199 entry.hdr = (union acpi_subtable_headers *) 200 ((unsigned long)entry.hdr + entry_len); 201 } 202 203 if (max_entries && count > max_entries) { 204 pr_warn("[%4.4s:0x%02x] ignored %i entries of %i found\n", 205 id, proc->id, count - max_entries, count); 206 } 207 208 return count; 209 } 210 211 int __init_or_fwtbl_lib 212 cdat_table_parse(enum acpi_cdat_type type, 213 acpi_tbl_entry_handler_arg handler_arg, 214 void *arg, 215 struct acpi_table_cdat *table_header, 216 unsigned long length) 217 { 218 struct acpi_subtable_proc proc = { 219 .id = type, 220 .handler_arg = handler_arg, 221 .arg = arg, 222 }; 223 224 if (!table_header) 225 return -EINVAL; 226 227 return acpi_parse_entries_array(ACPI_SIG_CDAT, 228 sizeof(struct acpi_table_cdat), 229 (union fw_table_header *)table_header, 230 length, &proc, 1, 0); 231 } 232 EXPORT_SYMBOL_FWTBL_LIB(cdat_table_parse); 233