xref: /linux/arch/x86/kernel/mpparse.c (revision 6c363eafc4d637ac4bd83d4a7dd06dd3cfbe7c5f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *	Intel Multiprocessor Specification 1.1 and 1.4
4  *	compliant MP-table parsing routines.
5  *
6  *	(c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
7  *	(c) 1998, 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com>
8  *      (c) 2008 Alexey Starikovskiy <astarikovskiy@suse.de>
9  */
10 
11 #include <linux/mm.h>
12 #include <linux/init.h>
13 #include <linux/delay.h>
14 #include <linux/memblock.h>
15 #include <linux/kernel_stat.h>
16 #include <linux/mc146818rtc.h>
17 #include <linux/bitops.h>
18 #include <linux/acpi.h>
19 #include <linux/smp.h>
20 #include <linux/pci.h>
21 
22 #include <asm/io_apic.h>
23 #include <asm/acpi.h>
24 #include <asm/irqdomain.h>
25 #include <asm/mtrr.h>
26 #include <asm/mpspec.h>
27 #include <asm/proto.h>
28 #include <asm/bios_ebda.h>
29 #include <asm/e820/api.h>
30 #include <asm/setup.h>
31 #include <asm/smp.h>
32 
33 #include <asm/apic.h>
34 /*
35  * Checksum an MP configuration block.
36  */
37 
38 static int __init mpf_checksum(unsigned char *mp, int len)
39 {
40 	int sum = 0;
41 
42 	while (len--)
43 		sum += *mp++;
44 
45 	return sum & 0xFF;
46 }
47 
48 static void __init MP_processor_info(struct mpc_cpu *m)
49 {
50 	int apicid;
51 	char *bootup_cpu = "";
52 
53 	if (!(m->cpuflag & CPU_ENABLED)) {
54 		disabled_cpus++;
55 		return;
56 	}
57 
58 	apicid = m->apicid;
59 
60 	if (m->cpuflag & CPU_BOOTPROCESSOR) {
61 		bootup_cpu = " (Bootup-CPU)";
62 		boot_cpu_physical_apicid = m->apicid;
63 	}
64 
65 	pr_info("Processor #%d%s\n", m->apicid, bootup_cpu);
66 	generic_processor_info(apicid, m->apicver);
67 }
68 
69 #ifdef CONFIG_X86_IO_APIC
70 static void __init mpc_oem_bus_info(struct mpc_bus *m, char *str)
71 {
72 	memcpy(str, m->bustype, 6);
73 	str[6] = 0;
74 	apic_printk(APIC_VERBOSE, "Bus #%d is %s\n", m->busid, str);
75 }
76 
77 static void __init MP_bus_info(struct mpc_bus *m)
78 {
79 	char str[7];
80 
81 	mpc_oem_bus_info(m, str);
82 
83 #if MAX_MP_BUSSES < 256
84 	if (m->busid >= MAX_MP_BUSSES) {
85 		pr_warn("MP table busid value (%d) for bustype %s is too large, max. supported is %d\n",
86 			m->busid, str, MAX_MP_BUSSES - 1);
87 		return;
88 	}
89 #endif
90 
91 	set_bit(m->busid, mp_bus_not_pci);
92 	if (strncmp(str, BUSTYPE_ISA, sizeof(BUSTYPE_ISA) - 1) == 0) {
93 #ifdef CONFIG_EISA
94 		mp_bus_id_to_type[m->busid] = MP_BUS_ISA;
95 #endif
96 	} else if (strncmp(str, BUSTYPE_PCI, sizeof(BUSTYPE_PCI) - 1) == 0) {
97 		clear_bit(m->busid, mp_bus_not_pci);
98 #ifdef CONFIG_EISA
99 		mp_bus_id_to_type[m->busid] = MP_BUS_PCI;
100 	} else if (strncmp(str, BUSTYPE_EISA, sizeof(BUSTYPE_EISA) - 1) == 0) {
101 		mp_bus_id_to_type[m->busid] = MP_BUS_EISA;
102 #endif
103 	} else
104 		pr_warn("Unknown bustype %s - ignoring\n", str);
105 }
106 
107 static void __init MP_ioapic_info(struct mpc_ioapic *m)
108 {
109 	struct ioapic_domain_cfg cfg = {
110 		.type = IOAPIC_DOMAIN_LEGACY,
111 		.ops = &mp_ioapic_irqdomain_ops,
112 	};
113 
114 	if (m->flags & MPC_APIC_USABLE)
115 		mp_register_ioapic(m->apicid, m->apicaddr, gsi_top, &cfg);
116 }
117 
118 static void __init print_mp_irq_info(struct mpc_intsrc *mp_irq)
119 {
120 	apic_printk(APIC_VERBOSE,
121 		"Int: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC INT %02x\n",
122 		mp_irq->irqtype, mp_irq->irqflag & 3,
123 		(mp_irq->irqflag >> 2) & 3, mp_irq->srcbus,
124 		mp_irq->srcbusirq, mp_irq->dstapic, mp_irq->dstirq);
125 }
126 
127 #else /* CONFIG_X86_IO_APIC */
128 static inline void __init MP_bus_info(struct mpc_bus *m) {}
129 static inline void __init MP_ioapic_info(struct mpc_ioapic *m) {}
130 #endif /* CONFIG_X86_IO_APIC */
131 
132 static void __init MP_lintsrc_info(struct mpc_lintsrc *m)
133 {
134 	apic_printk(APIC_VERBOSE,
135 		"Lint: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC LINT %02x\n",
136 		m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbusid,
137 		m->srcbusirq, m->destapic, m->destapiclint);
138 }
139 
140 /*
141  * Read/parse the MPC
142  */
143 static int __init smp_check_mpc(struct mpc_table *mpc, char *oem, char *str)
144 {
145 
146 	if (memcmp(mpc->signature, MPC_SIGNATURE, 4)) {
147 		pr_err("MPTABLE: bad signature [%c%c%c%c]!\n",
148 		       mpc->signature[0], mpc->signature[1],
149 		       mpc->signature[2], mpc->signature[3]);
150 		return 0;
151 	}
152 	if (mpf_checksum((unsigned char *)mpc, mpc->length)) {
153 		pr_err("MPTABLE: checksum error!\n");
154 		return 0;
155 	}
156 	if (mpc->spec != 0x01 && mpc->spec != 0x04) {
157 		pr_err("MPTABLE: bad table version (%d)!!\n", mpc->spec);
158 		return 0;
159 	}
160 	if (!mpc->lapic) {
161 		pr_err("MPTABLE: null local APIC address!\n");
162 		return 0;
163 	}
164 	memcpy(oem, mpc->oem, 8);
165 	oem[8] = 0;
166 	pr_info("MPTABLE: OEM ID: %s\n", oem);
167 
168 	memcpy(str, mpc->productid, 12);
169 	str[12] = 0;
170 
171 	pr_info("MPTABLE: Product ID: %s\n", str);
172 
173 	pr_info("MPTABLE: APIC at: 0x%X\n", mpc->lapic);
174 
175 	return 1;
176 }
177 
178 static void skip_entry(unsigned char **ptr, int *count, int size)
179 {
180 	*ptr += size;
181 	*count += size;
182 }
183 
184 static void __init smp_dump_mptable(struct mpc_table *mpc, unsigned char *mpt)
185 {
186 	pr_err("Your mptable is wrong, contact your HW vendor!\n");
187 	pr_cont("type %x\n", *mpt);
188 	print_hex_dump(KERN_ERR, "  ", DUMP_PREFIX_ADDRESS, 16,
189 			1, mpc, mpc->length, 1);
190 }
191 
192 static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
193 {
194 	char str[16];
195 	char oem[10];
196 
197 	int count = sizeof(*mpc);
198 	unsigned char *mpt = ((unsigned char *)mpc) + count;
199 
200 	if (!smp_check_mpc(mpc, oem, str))
201 		return 0;
202 
203 	/* Initialize the lapic mapping */
204 	if (!acpi_lapic)
205 		register_lapic_address(mpc->lapic);
206 
207 	if (early)
208 		return 1;
209 
210 	/* Now process the configuration blocks. */
211 	while (count < mpc->length) {
212 		switch (*mpt) {
213 		case MP_PROCESSOR:
214 			/* ACPI may have already provided this data */
215 			if (!acpi_lapic)
216 				MP_processor_info((struct mpc_cpu *)mpt);
217 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
218 			break;
219 		case MP_BUS:
220 			MP_bus_info((struct mpc_bus *)mpt);
221 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
222 			break;
223 		case MP_IOAPIC:
224 			MP_ioapic_info((struct mpc_ioapic *)mpt);
225 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
226 			break;
227 		case MP_INTSRC:
228 			mp_save_irq((struct mpc_intsrc *)mpt);
229 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
230 			break;
231 		case MP_LINTSRC:
232 			MP_lintsrc_info((struct mpc_lintsrc *)mpt);
233 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
234 			break;
235 		default:
236 			/* wrong mptable */
237 			smp_dump_mptable(mpc, mpt);
238 			count = mpc->length;
239 			break;
240 		}
241 	}
242 
243 	if (!num_processors)
244 		pr_err("MPTABLE: no processors registered!\n");
245 	return num_processors;
246 }
247 
248 #ifdef CONFIG_X86_IO_APIC
249 
250 static int __init ELCR_trigger(unsigned int irq)
251 {
252 	unsigned int port;
253 
254 	port = 0x4d0 + (irq >> 3);
255 	return (inb(port) >> (irq & 7)) & 1;
256 }
257 
258 static void __init construct_default_ioirq_mptable(int mpc_default_type)
259 {
260 	struct mpc_intsrc intsrc;
261 	int i;
262 	int ELCR_fallback = 0;
263 
264 	intsrc.type = MP_INTSRC;
265 	intsrc.irqflag = MP_IRQTRIG_DEFAULT | MP_IRQPOL_DEFAULT;
266 	intsrc.srcbus = 0;
267 	intsrc.dstapic = mpc_ioapic_id(0);
268 
269 	intsrc.irqtype = mp_INT;
270 
271 	/*
272 	 *  If true, we have an ISA/PCI system with no IRQ entries
273 	 *  in the MP table. To prevent the PCI interrupts from being set up
274 	 *  incorrectly, we try to use the ELCR. The sanity check to see if
275 	 *  there is good ELCR data is very simple - IRQ0, 1, 2 and 13 can
276 	 *  never be level sensitive, so we simply see if the ELCR agrees.
277 	 *  If it does, we assume it's valid.
278 	 */
279 	if (mpc_default_type == 5) {
280 		pr_info("ISA/PCI bus type with no IRQ information... falling back to ELCR\n");
281 
282 		if (ELCR_trigger(0) || ELCR_trigger(1) || ELCR_trigger(2) ||
283 		    ELCR_trigger(13))
284 			pr_err("ELCR contains invalid data... not using ELCR\n");
285 		else {
286 			pr_info("Using ELCR to identify PCI interrupts\n");
287 			ELCR_fallback = 1;
288 		}
289 	}
290 
291 	for (i = 0; i < 16; i++) {
292 		switch (mpc_default_type) {
293 		case 2:
294 			if (i == 0 || i == 13)
295 				continue;	/* IRQ0 & IRQ13 not connected */
296 			fallthrough;
297 		default:
298 			if (i == 2)
299 				continue;	/* IRQ2 is never connected */
300 		}
301 
302 		if (ELCR_fallback) {
303 			/*
304 			 *  If the ELCR indicates a level-sensitive interrupt, we
305 			 *  copy that information over to the MP table in the
306 			 *  irqflag field (level sensitive, active high polarity).
307 			 */
308 			if (ELCR_trigger(i)) {
309 				intsrc.irqflag = MP_IRQTRIG_LEVEL |
310 						 MP_IRQPOL_ACTIVE_HIGH;
311 			} else {
312 				intsrc.irqflag = MP_IRQTRIG_DEFAULT |
313 						 MP_IRQPOL_DEFAULT;
314 			}
315 		}
316 
317 		intsrc.srcbusirq = i;
318 		intsrc.dstirq = i ? i : 2;	/* IRQ0 to INTIN2 */
319 		mp_save_irq(&intsrc);
320 	}
321 
322 	intsrc.irqtype = mp_ExtINT;
323 	intsrc.srcbusirq = 0;
324 	intsrc.dstirq = 0;	/* 8259A to INTIN0 */
325 	mp_save_irq(&intsrc);
326 }
327 
328 
329 static void __init construct_ioapic_table(int mpc_default_type)
330 {
331 	struct mpc_ioapic ioapic;
332 	struct mpc_bus bus;
333 
334 	bus.type = MP_BUS;
335 	bus.busid = 0;
336 	switch (mpc_default_type) {
337 	default:
338 		pr_err("???\nUnknown standard configuration %d\n",
339 		       mpc_default_type);
340 		fallthrough;
341 	case 1:
342 	case 5:
343 		memcpy(bus.bustype, "ISA   ", 6);
344 		break;
345 	case 2:
346 	case 6:
347 	case 3:
348 		memcpy(bus.bustype, "EISA  ", 6);
349 		break;
350 	}
351 	MP_bus_info(&bus);
352 	if (mpc_default_type > 4) {
353 		bus.busid = 1;
354 		memcpy(bus.bustype, "PCI   ", 6);
355 		MP_bus_info(&bus);
356 	}
357 
358 	ioapic.type	= MP_IOAPIC;
359 	ioapic.apicid	= 2;
360 	ioapic.apicver	= mpc_default_type > 4 ? 0x10 : 0x01;
361 	ioapic.flags	= MPC_APIC_USABLE;
362 	ioapic.apicaddr	= IO_APIC_DEFAULT_PHYS_BASE;
363 	MP_ioapic_info(&ioapic);
364 
365 	/*
366 	 * We set up most of the low 16 IO-APIC pins according to MPS rules.
367 	 */
368 	construct_default_ioirq_mptable(mpc_default_type);
369 }
370 #else
371 static inline void __init construct_ioapic_table(int mpc_default_type) { }
372 #endif
373 
374 static inline void __init construct_default_ISA_mptable(int mpc_default_type)
375 {
376 	struct mpc_cpu processor;
377 	struct mpc_lintsrc lintsrc;
378 	int linttypes[2] = { mp_ExtINT, mp_NMI };
379 	int i;
380 
381 	/*
382 	 * local APIC has default address
383 	 */
384 	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
385 
386 	/*
387 	 * 2 CPUs, numbered 0 & 1.
388 	 */
389 	processor.type = MP_PROCESSOR;
390 	/* Either an integrated APIC or a discrete 82489DX. */
391 	processor.apicver = mpc_default_type > 4 ? 0x10 : 0x01;
392 	processor.cpuflag = CPU_ENABLED;
393 	processor.cpufeature = (boot_cpu_data.x86 << 8) |
394 	    (boot_cpu_data.x86_model << 4) | boot_cpu_data.x86_stepping;
395 	processor.featureflag = boot_cpu_data.x86_capability[CPUID_1_EDX];
396 	processor.reserved[0] = 0;
397 	processor.reserved[1] = 0;
398 	for (i = 0; i < 2; i++) {
399 		processor.apicid = i;
400 		MP_processor_info(&processor);
401 	}
402 
403 	construct_ioapic_table(mpc_default_type);
404 
405 	lintsrc.type = MP_LINTSRC;
406 	lintsrc.irqflag = MP_IRQTRIG_DEFAULT | MP_IRQPOL_DEFAULT;
407 	lintsrc.srcbusid = 0;
408 	lintsrc.srcbusirq = 0;
409 	lintsrc.destapic = MP_APIC_ALL;
410 	for (i = 0; i < 2; i++) {
411 		lintsrc.irqtype = linttypes[i];
412 		lintsrc.destapiclint = i;
413 		MP_lintsrc_info(&lintsrc);
414 	}
415 }
416 
417 static unsigned long mpf_base;
418 static bool mpf_found;
419 
420 static unsigned long __init get_mpc_size(unsigned long physptr)
421 {
422 	struct mpc_table *mpc;
423 	unsigned long size;
424 
425 	mpc = early_memremap(physptr, PAGE_SIZE);
426 	size = mpc->length;
427 	early_memunmap(mpc, PAGE_SIZE);
428 	apic_printk(APIC_VERBOSE, "  mpc: %lx-%lx\n", physptr, physptr + size);
429 
430 	return size;
431 }
432 
433 static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
434 {
435 	struct mpc_table *mpc;
436 	unsigned long size;
437 
438 	size = get_mpc_size(mpf->physptr);
439 	mpc = early_memremap(mpf->physptr, size);
440 
441 	/*
442 	 * Read the physical hardware table.  Anything here will
443 	 * override the defaults.
444 	 */
445 	if (!smp_read_mpc(mpc, early)) {
446 #ifdef CONFIG_X86_LOCAL_APIC
447 		smp_found_config = 0;
448 #endif
449 		pr_err("BIOS bug, MP table errors detected!...\n");
450 		pr_cont("... disabling SMP support. (tell your hw vendor)\n");
451 		early_memunmap(mpc, size);
452 		return -1;
453 	}
454 	early_memunmap(mpc, size);
455 
456 	if (early)
457 		return -1;
458 
459 #ifdef CONFIG_X86_IO_APIC
460 	/*
461 	 * If there are no explicit MP IRQ entries, then we are
462 	 * broken.  We set up most of the low 16 IO-APIC pins to
463 	 * ISA defaults and hope it will work.
464 	 */
465 	if (!mp_irq_entries) {
466 		struct mpc_bus bus;
467 
468 		pr_err("BIOS bug, no explicit IRQ entries, using default mptable. (tell your hw vendor)\n");
469 
470 		bus.type = MP_BUS;
471 		bus.busid = 0;
472 		memcpy(bus.bustype, "ISA   ", 6);
473 		MP_bus_info(&bus);
474 
475 		construct_default_ioirq_mptable(0);
476 	}
477 #endif
478 
479 	return 0;
480 }
481 
482 /*
483  * Scan the memory blocks for an SMP configuration block.
484  */
485 void __init default_get_smp_config(unsigned int early)
486 {
487 	struct mpf_intel *mpf;
488 
489 	if (!smp_found_config)
490 		return;
491 
492 	if (!mpf_found)
493 		return;
494 
495 	if (acpi_lapic && early)
496 		return;
497 
498 	/*
499 	 * MPS doesn't support hyperthreading, aka only have
500 	 * thread 0 apic id in MPS table
501 	 */
502 	if (acpi_lapic && acpi_ioapic)
503 		return;
504 
505 	mpf = early_memremap(mpf_base, sizeof(*mpf));
506 	if (!mpf) {
507 		pr_err("MPTABLE: error mapping MP table\n");
508 		return;
509 	}
510 
511 	pr_info("Intel MultiProcessor Specification v1.%d\n",
512 		mpf->specification);
513 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
514 	if (mpf->feature2 & (1 << 7)) {
515 		pr_info("    IMCR and PIC compatibility mode.\n");
516 		pic_mode = 1;
517 	} else {
518 		pr_info("    Virtual Wire compatibility mode.\n");
519 		pic_mode = 0;
520 	}
521 #endif
522 	/*
523 	 * Now see if we need to read further.
524 	 */
525 	if (mpf->feature1) {
526 		if (early) {
527 			/*
528 			 * local APIC has default address
529 			 */
530 			mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
531 			goto out;
532 		}
533 
534 		pr_info("Default MP configuration #%d\n", mpf->feature1);
535 		construct_default_ISA_mptable(mpf->feature1);
536 
537 	} else if (mpf->physptr) {
538 		if (check_physptr(mpf, early))
539 			goto out;
540 	} else
541 		BUG();
542 
543 	if (!early)
544 		pr_info("Processors: %d\n", num_processors);
545 	/*
546 	 * Only use the first configuration found.
547 	 */
548 out:
549 	early_memunmap(mpf, sizeof(*mpf));
550 }
551 
552 static void __init smp_reserve_memory(struct mpf_intel *mpf)
553 {
554 	memblock_reserve(mpf->physptr, get_mpc_size(mpf->physptr));
555 }
556 
557 static int __init smp_scan_config(unsigned long base, unsigned long length)
558 {
559 	unsigned int *bp;
560 	struct mpf_intel *mpf;
561 	int ret = 0;
562 
563 	apic_printk(APIC_VERBOSE, "Scan for SMP in [mem %#010lx-%#010lx]\n",
564 		    base, base + length - 1);
565 	BUILD_BUG_ON(sizeof(*mpf) != 16);
566 
567 	while (length > 0) {
568 		bp = early_memremap(base, length);
569 		mpf = (struct mpf_intel *)bp;
570 		if ((*bp == SMP_MAGIC_IDENT) &&
571 		    (mpf->length == 1) &&
572 		    !mpf_checksum((unsigned char *)bp, 16) &&
573 		    ((mpf->specification == 1)
574 		     || (mpf->specification == 4))) {
575 #ifdef CONFIG_X86_LOCAL_APIC
576 			smp_found_config = 1;
577 #endif
578 			mpf_base = base;
579 			mpf_found = true;
580 
581 			pr_info("found SMP MP-table at [mem %#010lx-%#010lx]\n",
582 				base, base + sizeof(*mpf) - 1);
583 
584 			memblock_reserve(base, sizeof(*mpf));
585 			if (mpf->physptr)
586 				smp_reserve_memory(mpf);
587 
588 			ret = 1;
589 		}
590 		early_memunmap(bp, length);
591 
592 		if (ret)
593 			break;
594 
595 		base += 16;
596 		length -= 16;
597 	}
598 	return ret;
599 }
600 
601 void __init default_find_smp_config(void)
602 {
603 	unsigned int address;
604 
605 	/*
606 	 * FIXME: Linux assumes you have 640K of base ram..
607 	 * this continues the error...
608 	 *
609 	 * 1) Scan the bottom 1K for a signature
610 	 * 2) Scan the top 1K of base RAM
611 	 * 3) Scan the 64K of bios
612 	 */
613 	if (smp_scan_config(0x0, 0x400) ||
614 	    smp_scan_config(639 * 0x400, 0x400) ||
615 	    smp_scan_config(0xF0000, 0x10000))
616 		return;
617 	/*
618 	 * If it is an SMP machine we should know now, unless the
619 	 * configuration is in an EISA bus machine with an
620 	 * extended bios data area.
621 	 *
622 	 * there is a real-mode segmented pointer pointing to the
623 	 * 4K EBDA area at 0x40E, calculate and scan it here.
624 	 *
625 	 * NOTE! There are Linux loaders that will corrupt the EBDA
626 	 * area, and as such this kind of SMP config may be less
627 	 * trustworthy, simply because the SMP table may have been
628 	 * stomped on during early boot. These loaders are buggy and
629 	 * should be fixed.
630 	 *
631 	 * MP1.4 SPEC states to only scan first 1K of 4K EBDA.
632 	 */
633 
634 	address = get_bios_ebda();
635 	if (address)
636 		smp_scan_config(address, 0x400);
637 }
638 
639 #ifdef CONFIG_X86_IO_APIC
640 static u8 __initdata irq_used[MAX_IRQ_SOURCES];
641 
642 static int  __init get_MP_intsrc_index(struct mpc_intsrc *m)
643 {
644 	int i;
645 
646 	if (m->irqtype != mp_INT)
647 		return 0;
648 
649 	if (m->irqflag != (MP_IRQTRIG_LEVEL | MP_IRQPOL_ACTIVE_LOW))
650 		return 0;
651 
652 	/* not legacy */
653 
654 	for (i = 0; i < mp_irq_entries; i++) {
655 		if (mp_irqs[i].irqtype != mp_INT)
656 			continue;
657 
658 		if (mp_irqs[i].irqflag != (MP_IRQTRIG_LEVEL |
659 					   MP_IRQPOL_ACTIVE_LOW))
660 			continue;
661 
662 		if (mp_irqs[i].srcbus != m->srcbus)
663 			continue;
664 		if (mp_irqs[i].srcbusirq != m->srcbusirq)
665 			continue;
666 		if (irq_used[i]) {
667 			/* already claimed */
668 			return -2;
669 		}
670 		irq_used[i] = 1;
671 		return i;
672 	}
673 
674 	/* not found */
675 	return -1;
676 }
677 
678 #define SPARE_SLOT_NUM 20
679 
680 static struct mpc_intsrc __initdata *m_spare[SPARE_SLOT_NUM];
681 
682 static void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare)
683 {
684 	int i;
685 
686 	apic_printk(APIC_VERBOSE, "OLD ");
687 	print_mp_irq_info(m);
688 
689 	i = get_MP_intsrc_index(m);
690 	if (i > 0) {
691 		memcpy(m, &mp_irqs[i], sizeof(*m));
692 		apic_printk(APIC_VERBOSE, "NEW ");
693 		print_mp_irq_info(&mp_irqs[i]);
694 		return;
695 	}
696 	if (!i) {
697 		/* legacy, do nothing */
698 		return;
699 	}
700 	if (*nr_m_spare < SPARE_SLOT_NUM) {
701 		/*
702 		 * not found (-1), or duplicated (-2) are invalid entries,
703 		 * we need to use the slot later
704 		 */
705 		m_spare[*nr_m_spare] = m;
706 		*nr_m_spare += 1;
707 	}
708 }
709 
710 static int __init
711 check_slot(unsigned long mpc_new_phys, unsigned long mpc_new_length, int count)
712 {
713 	if (!mpc_new_phys || count <= mpc_new_length) {
714 		WARN(1, "update_mptable: No spare slots (length: %x)\n", count);
715 		return -1;
716 	}
717 
718 	return 0;
719 }
720 #else /* CONFIG_X86_IO_APIC */
721 static
722 inline void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare) {}
723 #endif /* CONFIG_X86_IO_APIC */
724 
725 static int  __init replace_intsrc_all(struct mpc_table *mpc,
726 					unsigned long mpc_new_phys,
727 					unsigned long mpc_new_length)
728 {
729 #ifdef CONFIG_X86_IO_APIC
730 	int i;
731 #endif
732 	int count = sizeof(*mpc);
733 	int nr_m_spare = 0;
734 	unsigned char *mpt = ((unsigned char *)mpc) + count;
735 
736 	pr_info("mpc_length %x\n", mpc->length);
737 	while (count < mpc->length) {
738 		switch (*mpt) {
739 		case MP_PROCESSOR:
740 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
741 			break;
742 		case MP_BUS:
743 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
744 			break;
745 		case MP_IOAPIC:
746 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
747 			break;
748 		case MP_INTSRC:
749 			check_irq_src((struct mpc_intsrc *)mpt, &nr_m_spare);
750 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
751 			break;
752 		case MP_LINTSRC:
753 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
754 			break;
755 		default:
756 			/* wrong mptable */
757 			smp_dump_mptable(mpc, mpt);
758 			goto out;
759 		}
760 	}
761 
762 #ifdef CONFIG_X86_IO_APIC
763 	for (i = 0; i < mp_irq_entries; i++) {
764 		if (irq_used[i])
765 			continue;
766 
767 		if (mp_irqs[i].irqtype != mp_INT)
768 			continue;
769 
770 		if (mp_irqs[i].irqflag != (MP_IRQTRIG_LEVEL |
771 					   MP_IRQPOL_ACTIVE_LOW))
772 			continue;
773 
774 		if (nr_m_spare > 0) {
775 			apic_printk(APIC_VERBOSE, "*NEW* found\n");
776 			nr_m_spare--;
777 			memcpy(m_spare[nr_m_spare], &mp_irqs[i], sizeof(mp_irqs[i]));
778 			m_spare[nr_m_spare] = NULL;
779 		} else {
780 			struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
781 			count += sizeof(struct mpc_intsrc);
782 			if (check_slot(mpc_new_phys, mpc_new_length, count) < 0)
783 				goto out;
784 			memcpy(m, &mp_irqs[i], sizeof(*m));
785 			mpc->length = count;
786 			mpt += sizeof(struct mpc_intsrc);
787 		}
788 		print_mp_irq_info(&mp_irqs[i]);
789 	}
790 #endif
791 out:
792 	/* update checksum */
793 	mpc->checksum = 0;
794 	mpc->checksum -= mpf_checksum((unsigned char *)mpc, mpc->length);
795 
796 	return 0;
797 }
798 
799 int enable_update_mptable;
800 
801 static int __init update_mptable_setup(char *str)
802 {
803 	enable_update_mptable = 1;
804 #ifdef CONFIG_PCI
805 	pci_routeirq = 1;
806 #endif
807 	return 0;
808 }
809 early_param("update_mptable", update_mptable_setup);
810 
811 static unsigned long __initdata mpc_new_phys;
812 static unsigned long mpc_new_length __initdata = 4096;
813 
814 /* alloc_mptable or alloc_mptable=4k */
815 static int __initdata alloc_mptable;
816 static int __init parse_alloc_mptable_opt(char *p)
817 {
818 	enable_update_mptable = 1;
819 #ifdef CONFIG_PCI
820 	pci_routeirq = 1;
821 #endif
822 	alloc_mptable = 1;
823 	if (!p)
824 		return 0;
825 	mpc_new_length = memparse(p, &p);
826 	return 0;
827 }
828 early_param("alloc_mptable", parse_alloc_mptable_opt);
829 
830 void __init e820__memblock_alloc_reserved_mpc_new(void)
831 {
832 	if (enable_update_mptable && alloc_mptable)
833 		mpc_new_phys = e820__memblock_alloc_reserved(mpc_new_length, 4);
834 }
835 
836 static int __init update_mp_table(void)
837 {
838 	char str[16];
839 	char oem[10];
840 	struct mpf_intel *mpf;
841 	struct mpc_table *mpc, *mpc_new;
842 	unsigned long size;
843 
844 	if (!enable_update_mptable)
845 		return 0;
846 
847 	if (!mpf_found)
848 		return 0;
849 
850 	mpf = early_memremap(mpf_base, sizeof(*mpf));
851 	if (!mpf) {
852 		pr_err("MPTABLE: mpf early_memremap() failed\n");
853 		return 0;
854 	}
855 
856 	/*
857 	 * Now see if we need to go further.
858 	 */
859 	if (mpf->feature1)
860 		goto do_unmap_mpf;
861 
862 	if (!mpf->physptr)
863 		goto do_unmap_mpf;
864 
865 	size = get_mpc_size(mpf->physptr);
866 	mpc = early_memremap(mpf->physptr, size);
867 	if (!mpc) {
868 		pr_err("MPTABLE: mpc early_memremap() failed\n");
869 		goto do_unmap_mpf;
870 	}
871 
872 	if (!smp_check_mpc(mpc, oem, str))
873 		goto do_unmap_mpc;
874 
875 	pr_info("mpf: %llx\n", (u64)mpf_base);
876 	pr_info("physptr: %x\n", mpf->physptr);
877 
878 	if (mpc_new_phys && mpc->length > mpc_new_length) {
879 		mpc_new_phys = 0;
880 		pr_info("mpc_new_length is %ld, please use alloc_mptable=8k\n",
881 			mpc_new_length);
882 	}
883 
884 	if (!mpc_new_phys) {
885 		unsigned char old, new;
886 		/* check if we can change the position */
887 		mpc->checksum = 0;
888 		old = mpf_checksum((unsigned char *)mpc, mpc->length);
889 		mpc->checksum = 0xff;
890 		new = mpf_checksum((unsigned char *)mpc, mpc->length);
891 		if (old == new) {
892 			pr_info("mpc is readonly, please try alloc_mptable instead\n");
893 			goto do_unmap_mpc;
894 		}
895 		pr_info("use in-position replacing\n");
896 	} else {
897 		mpc_new = early_memremap(mpc_new_phys, mpc_new_length);
898 		if (!mpc_new) {
899 			pr_err("MPTABLE: new mpc early_memremap() failed\n");
900 			goto do_unmap_mpc;
901 		}
902 		mpf->physptr = mpc_new_phys;
903 		memcpy(mpc_new, mpc, mpc->length);
904 		early_memunmap(mpc, size);
905 		mpc = mpc_new;
906 		size = mpc_new_length;
907 		/* check if we can modify that */
908 		if (mpc_new_phys - mpf->physptr) {
909 			struct mpf_intel *mpf_new;
910 			/* steal 16 bytes from [0, 1k) */
911 			mpf_new = early_memremap(0x400 - 16, sizeof(*mpf_new));
912 			if (!mpf_new) {
913 				pr_err("MPTABLE: new mpf early_memremap() failed\n");
914 				goto do_unmap_mpc;
915 			}
916 			pr_info("mpf new: %x\n", 0x400 - 16);
917 			memcpy(mpf_new, mpf, 16);
918 			early_memunmap(mpf, sizeof(*mpf));
919 			mpf = mpf_new;
920 			mpf->physptr = mpc_new_phys;
921 		}
922 		mpf->checksum = 0;
923 		mpf->checksum -= mpf_checksum((unsigned char *)mpf, 16);
924 		pr_info("physptr new: %x\n", mpf->physptr);
925 	}
926 
927 	/*
928 	 * only replace the one with mp_INT and
929 	 *	 MP_IRQ_TRIGGER_LEVEL|MP_IRQ_POLARITY_LOW,
930 	 * already in mp_irqs , stored by ... and mp_config_acpi_gsi,
931 	 * may need pci=routeirq for all coverage
932 	 */
933 	replace_intsrc_all(mpc, mpc_new_phys, mpc_new_length);
934 
935 do_unmap_mpc:
936 	early_memunmap(mpc, size);
937 
938 do_unmap_mpf:
939 	early_memunmap(mpf, sizeof(*mpf));
940 
941 	return 0;
942 }
943 
944 late_initcall(update_mp_table);
945