1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * BIOS32 and PCI BIOS handling. 4 */ 5 6 #include <linux/pci.h> 7 #include <linux/init.h> 8 #include <linux/slab.h> 9 #include <linux/module.h> 10 #include <linux/uaccess.h> 11 12 #include <asm/pci_x86.h> 13 #include <asm/e820/types.h> 14 #include <asm/pci-functions.h> 15 #include <asm/set_memory.h> 16 17 /* BIOS32 signature: "_32_" */ 18 #define BIOS32_SIGNATURE (('_' << 0) + ('3' << 8) + ('2' << 16) + ('_' << 24)) 19 20 /* PCI signature: "PCI " */ 21 #define PCI_SIGNATURE (('P' << 0) + ('C' << 8) + ('I' << 16) + (' ' << 24)) 22 23 /* PCI service signature: "$PCI" */ 24 #define PCI_SERVICE (('$' << 0) + ('P' << 8) + ('C' << 16) + ('I' << 24)) 25 26 /* PCI BIOS hardware mechanism flags */ 27 #define PCIBIOS_HW_TYPE1 0x01 28 #define PCIBIOS_HW_TYPE2 0x02 29 #define PCIBIOS_HW_TYPE1_SPEC 0x10 30 #define PCIBIOS_HW_TYPE2_SPEC 0x20 31 32 int pcibios_enabled; 33 34 /* According to the BIOS specification at: 35 * http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could 36 * restrict the x zone to some pages and make it ro. But this may be 37 * broken on some bios, complex to handle with static_protections. 38 * We could make the 0xe0000-0x100000 range rox, but this can break 39 * some ISA mapping. 40 * 41 * So we let's an rw and x hole when pcibios is used. This shouldn't 42 * happen for modern system with mmconfig, and if you don't want it 43 * you could disable pcibios... 44 */ 45 static inline void set_bios_x(void) 46 { 47 pcibios_enabled = 1; 48 set_memory_x(PAGE_OFFSET + BIOS_BEGIN, (BIOS_END - BIOS_BEGIN) >> PAGE_SHIFT); 49 if (__supported_pte_mask & _PAGE_NX) 50 printk(KERN_INFO "PCI: PCI BIOS area is rw and x. Use pci=nobios if you want it NX.\n"); 51 } 52 53 /* 54 * This is the standard structure used to identify the entry point 55 * to the BIOS32 Service Directory, as documented in 56 * Standard BIOS 32-bit Service Directory Proposal 57 * Revision 0.4 May 24, 1993 58 * Phoenix Technologies Ltd. 59 * Norwood, MA 60 * and the PCI BIOS specification. 61 */ 62 63 union bios32 { 64 struct { 65 unsigned long signature; /* _32_ */ 66 unsigned long entry; /* 32 bit physical address */ 67 unsigned char revision; /* Revision level, 0 */ 68 unsigned char length; /* Length in paragraphs should be 01 */ 69 unsigned char checksum; /* All bytes must add up to zero */ 70 unsigned char reserved[5]; /* Must be zero */ 71 } fields; 72 char chars[16]; 73 }; 74 75 /* 76 * Physical address of the service directory. I don't know if we're 77 * allowed to have more than one of these or not, so just in case 78 * we'll make pcibios_present() take a memory start parameter and store 79 * the array there. 80 */ 81 82 static struct { 83 unsigned long address; 84 unsigned short segment; 85 } bios32_indirect __initdata = { 0, __KERNEL_CS }; 86 87 /* 88 * Returns the entry point for the given service, NULL on error 89 */ 90 91 static unsigned long __init bios32_service(unsigned long service) 92 { 93 unsigned char return_code; /* %al */ 94 unsigned long address; /* %ebx */ 95 unsigned long length; /* %ecx */ 96 unsigned long entry; /* %edx */ 97 unsigned long flags; 98 99 local_irq_save(flags); 100 __asm__("lcall *(%%edi); cld" 101 : "=a" (return_code), 102 "=b" (address), 103 "=c" (length), 104 "=d" (entry) 105 : "0" (service), 106 "1" (0), 107 "D" (&bios32_indirect)); 108 local_irq_restore(flags); 109 110 switch (return_code) { 111 case 0: 112 return address + entry; 113 case 0x80: /* Not present */ 114 printk(KERN_WARNING "bios32_service(0x%lx): not present\n", service); 115 return 0; 116 default: /* Shouldn't happen */ 117 printk(KERN_WARNING "bios32_service(0x%lx): returned 0x%x -- BIOS bug!\n", 118 service, return_code); 119 return 0; 120 } 121 } 122 123 static struct { 124 unsigned long address; 125 unsigned short segment; 126 } pci_indirect __ro_after_init = { 127 .address = 0, 128 .segment = __KERNEL_CS, 129 }; 130 131 static int pci_bios_present __ro_after_init; 132 133 static int __init check_pcibios(void) 134 { 135 u32 signature, eax, ebx, ecx; 136 u8 status, major_ver, minor_ver, hw_mech; 137 unsigned long flags, pcibios_entry; 138 139 if ((pcibios_entry = bios32_service(PCI_SERVICE))) { 140 pci_indirect.address = pcibios_entry + PAGE_OFFSET; 141 142 local_irq_save(flags); 143 __asm__( 144 "lcall *(%%edi); cld\n\t" 145 "jc 1f\n\t" 146 "xor %%ah, %%ah\n" 147 "1:" 148 : "=d" (signature), 149 "=a" (eax), 150 "=b" (ebx), 151 "=c" (ecx) 152 : "1" (PCIBIOS_PCI_BIOS_PRESENT), 153 "D" (&pci_indirect) 154 : "memory"); 155 local_irq_restore(flags); 156 157 status = (eax >> 8) & 0xff; 158 hw_mech = eax & 0xff; 159 major_ver = (ebx >> 8) & 0xff; 160 minor_ver = ebx & 0xff; 161 if (pcibios_last_bus < 0) 162 pcibios_last_bus = ecx & 0xff; 163 DBG("PCI: BIOS probe returned s=%02x hw=%02x ver=%02x.%02x l=%02x\n", 164 status, hw_mech, major_ver, minor_ver, pcibios_last_bus); 165 if (status || signature != PCI_SIGNATURE) { 166 printk (KERN_ERR "PCI: BIOS BUG #%x[%08x] found\n", 167 status, signature); 168 return 0; 169 } 170 printk(KERN_INFO "PCI: PCI BIOS revision %x.%02x entry at 0x%lx, last bus=%d\n", 171 major_ver, minor_ver, pcibios_entry, pcibios_last_bus); 172 #ifdef CONFIG_PCI_DIRECT 173 if (!(hw_mech & PCIBIOS_HW_TYPE1)) 174 pci_probe &= ~PCI_PROBE_CONF1; 175 if (!(hw_mech & PCIBIOS_HW_TYPE2)) 176 pci_probe &= ~PCI_PROBE_CONF2; 177 #endif 178 return 1; 179 } 180 return 0; 181 } 182 183 static int pci_bios_read(unsigned int seg, unsigned int bus, 184 unsigned int devfn, int reg, int len, u32 *value) 185 { 186 unsigned long result = 0; 187 unsigned long flags; 188 unsigned long bx = (bus << 8) | devfn; 189 u16 number = 0, mask = 0; 190 191 WARN_ON(seg); 192 if (!value || (bus > 255) || (devfn > 255) || (reg > 255)) 193 return -EINVAL; 194 195 raw_spin_lock_irqsave(&pci_config_lock, flags); 196 197 switch (len) { 198 case 1: 199 number = PCIBIOS_READ_CONFIG_BYTE; 200 mask = 0xff; 201 break; 202 case 2: 203 number = PCIBIOS_READ_CONFIG_WORD; 204 mask = 0xffff; 205 break; 206 case 4: 207 number = PCIBIOS_READ_CONFIG_DWORD; 208 break; 209 } 210 211 __asm__("lcall *(%%esi); cld\n\t" 212 "jc 1f\n\t" 213 "xor %%ah, %%ah\n" 214 "1:" 215 : "=c" (*value), 216 "=a" (result) 217 : "1" (number), 218 "b" (bx), 219 "D" ((long)reg), 220 "S" (&pci_indirect)); 221 /* 222 * Zero-extend the result beyond 8 or 16 bits, do not trust the 223 * BIOS having done it: 224 */ 225 if (mask) 226 *value &= mask; 227 228 raw_spin_unlock_irqrestore(&pci_config_lock, flags); 229 230 return (int)((result & 0xff00) >> 8); 231 } 232 233 static int pci_bios_write(unsigned int seg, unsigned int bus, 234 unsigned int devfn, int reg, int len, u32 value) 235 { 236 unsigned long result = 0; 237 unsigned long flags; 238 unsigned long bx = (bus << 8) | devfn; 239 u16 number = 0; 240 241 WARN_ON(seg); 242 if ((bus > 255) || (devfn > 255) || (reg > 255)) 243 return -EINVAL; 244 245 raw_spin_lock_irqsave(&pci_config_lock, flags); 246 247 switch (len) { 248 case 1: 249 number = PCIBIOS_WRITE_CONFIG_BYTE; 250 break; 251 case 2: 252 number = PCIBIOS_WRITE_CONFIG_WORD; 253 break; 254 case 4: 255 number = PCIBIOS_WRITE_CONFIG_DWORD; 256 break; 257 } 258 259 __asm__("lcall *(%%esi); cld\n\t" 260 "jc 1f\n\t" 261 "xor %%ah, %%ah\n" 262 "1:" 263 : "=a" (result) 264 : "0" (number), 265 "c" (value), 266 "b" (bx), 267 "D" ((long)reg), 268 "S" (&pci_indirect)); 269 270 raw_spin_unlock_irqrestore(&pci_config_lock, flags); 271 272 return (int)((result & 0xff00) >> 8); 273 } 274 275 276 /* 277 * Function table for BIOS32 access 278 */ 279 280 static const struct pci_raw_ops pci_bios_access = { 281 .read = pci_bios_read, 282 .write = pci_bios_write 283 }; 284 285 /* 286 * Try to find PCI BIOS. 287 */ 288 289 static const struct pci_raw_ops *__init pci_find_bios(void) 290 { 291 union bios32 *check; 292 unsigned char sum; 293 int i, length; 294 295 /* 296 * Follow the standard procedure for locating the BIOS32 Service 297 * directory by scanning the permissible address range from 298 * 0xe0000 through 0xfffff for a valid BIOS32 structure. 299 */ 300 301 for (check = (union bios32 *) __va(0xe0000); 302 check <= (union bios32 *) __va(0xffff0); 303 ++check) { 304 long sig; 305 if (probe_kernel_address(&check->fields.signature, sig)) 306 continue; 307 308 if (check->fields.signature != BIOS32_SIGNATURE) 309 continue; 310 length = check->fields.length * 16; 311 if (!length) 312 continue; 313 sum = 0; 314 for (i = 0; i < length ; ++i) 315 sum += check->chars[i]; 316 if (sum != 0) 317 continue; 318 if (check->fields.revision != 0) { 319 printk("PCI: unsupported BIOS32 revision %d at 0x%p\n", 320 check->fields.revision, check); 321 continue; 322 } 323 DBG("PCI: BIOS32 Service Directory structure at 0x%p\n", check); 324 if (check->fields.entry >= 0x100000) { 325 printk("PCI: BIOS32 entry (0x%p) in high memory, " 326 "cannot use.\n", check); 327 return NULL; 328 } else { 329 unsigned long bios32_entry = check->fields.entry; 330 DBG("PCI: BIOS32 Service Directory entry at 0x%lx\n", 331 bios32_entry); 332 bios32_indirect.address = bios32_entry + PAGE_OFFSET; 333 set_bios_x(); 334 if (check_pcibios()) 335 return &pci_bios_access; 336 } 337 break; /* Hopefully more than one BIOS32 cannot happen... */ 338 } 339 340 return NULL; 341 } 342 343 /* 344 * BIOS Functions for IRQ Routing 345 */ 346 347 struct irq_routing_options { 348 u16 size; 349 struct irq_info *table; 350 u16 segment; 351 } __attribute__((packed)); 352 353 struct irq_routing_table * pcibios_get_irq_routing_table(void) 354 { 355 struct irq_routing_options opt; 356 struct irq_routing_table *rt = NULL; 357 int ret, map; 358 unsigned long page; 359 360 if (!pci_bios_present) 361 return NULL; 362 page = __get_free_page(GFP_KERNEL); 363 if (!page) 364 return NULL; 365 opt.table = (struct irq_info *) page; 366 opt.size = PAGE_SIZE; 367 opt.segment = __KERNEL_DS; 368 369 DBG("PCI: Fetching IRQ routing table... "); 370 __asm__("push %%es\n\t" 371 "push %%ds\n\t" 372 "pop %%es\n\t" 373 "lcall *(%%esi); cld\n\t" 374 "pop %%es\n\t" 375 "jc 1f\n\t" 376 "xor %%ah, %%ah\n" 377 "1:" 378 : "=a" (ret), 379 "=b" (map), 380 "=m" (opt) 381 : "0" (PCIBIOS_GET_ROUTING_OPTIONS), 382 "1" (0), 383 "D" ((long) &opt), 384 "S" (&pci_indirect), 385 "m" (opt) 386 : "memory"); 387 DBG("OK ret=%d, size=%d, map=%x\n", ret, opt.size, map); 388 if (ret & 0xff00) 389 printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff); 390 else if (opt.size) { 391 rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL); 392 if (rt) { 393 memset(rt, 0, sizeof(struct irq_routing_table)); 394 rt->size = opt.size + sizeof(struct irq_routing_table); 395 rt->exclusive_irqs = map; 396 memcpy(rt->slots, (void *) page, opt.size); 397 printk(KERN_INFO "PCI: Using BIOS Interrupt Routing Table\n"); 398 } 399 } 400 free_page(page); 401 return rt; 402 } 403 EXPORT_SYMBOL(pcibios_get_irq_routing_table); 404 405 int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq) 406 { 407 int ret; 408 409 __asm__("lcall *(%%esi); cld\n\t" 410 "jc 1f\n\t" 411 "xor %%ah, %%ah\n" 412 "1:" 413 : "=a" (ret) 414 : "0" (PCIBIOS_SET_PCI_HW_INT), 415 "b" ((dev->bus->number << 8) | dev->devfn), 416 "c" ((irq << 8) | (pin + 10)), 417 "S" (&pci_indirect)); 418 return !(ret & 0xff00); 419 } 420 EXPORT_SYMBOL(pcibios_set_irq_routing); 421 422 void __init pci_pcbios_init(void) 423 { 424 if ((pci_probe & PCI_PROBE_BIOS) 425 && ((raw_pci_ops = pci_find_bios()))) { 426 pci_bios_present = 1; 427 } 428 } 429 430