xref: /openbmc/linux/arch/x86/kernel/mpparse.c (revision b24413180f5600bcb3bb70fbed5cf186b60864bd)
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/bootmem.h>
15 #include <linux/memblock.h>
16 #include <linux/kernel_stat.h>
17 #include <linux/mc146818rtc.h>
18 #include <linux/bitops.h>
19 #include <linux/acpi.h>
20 #include <linux/smp.h>
21 #include <linux/pci.h>
22 
23 #include <asm/irqdomain.h>
24 #include <asm/mtrr.h>
25 #include <asm/mpspec.h>
26 #include <asm/pgalloc.h>
27 #include <asm/io_apic.h>
28 #include <asm/proto.h>
29 #include <asm/bios_ebda.h>
30 #include <asm/e820/api.h>
31 #include <asm/setup.h>
32 #include <asm/smp.h>
33 
34 #include <asm/apic.h>
35 /*
36  * Checksum an MP configuration block.
37  */
38 
39 static int __init mpf_checksum(unsigned char *mp, int len)
40 {
41 	int sum = 0;
42 
43 	while (len--)
44 		sum += *mp++;
45 
46 	return sum & 0xFF;
47 }
48 
49 int __init default_mpc_apic_id(struct mpc_cpu *m)
50 {
51 	return m->apicid;
52 }
53 
54 static void __init MP_processor_info(struct mpc_cpu *m)
55 {
56 	int apicid;
57 	char *bootup_cpu = "";
58 
59 	if (!(m->cpuflag & CPU_ENABLED)) {
60 		disabled_cpus++;
61 		return;
62 	}
63 
64 	apicid = x86_init.mpparse.mpc_apic_id(m);
65 
66 	if (m->cpuflag & CPU_BOOTPROCESSOR) {
67 		bootup_cpu = " (Bootup-CPU)";
68 		boot_cpu_physical_apicid = m->apicid;
69 	}
70 
71 	pr_info("Processor #%d%s\n", m->apicid, bootup_cpu);
72 	generic_processor_info(apicid, m->apicver);
73 }
74 
75 #ifdef CONFIG_X86_IO_APIC
76 void __init default_mpc_oem_bus_info(struct mpc_bus *m, char *str)
77 {
78 	memcpy(str, m->bustype, 6);
79 	str[6] = 0;
80 	apic_printk(APIC_VERBOSE, "Bus #%d is %s\n", m->busid, str);
81 }
82 
83 static void __init MP_bus_info(struct mpc_bus *m)
84 {
85 	char str[7];
86 
87 	x86_init.mpparse.mpc_oem_bus_info(m, str);
88 
89 #if MAX_MP_BUSSES < 256
90 	if (m->busid >= MAX_MP_BUSSES) {
91 		pr_warn("MP table busid value (%d) for bustype %s is too large, max. supported is %d\n",
92 			m->busid, str, MAX_MP_BUSSES - 1);
93 		return;
94 	}
95 #endif
96 
97 	set_bit(m->busid, mp_bus_not_pci);
98 	if (strncmp(str, BUSTYPE_ISA, sizeof(BUSTYPE_ISA) - 1) == 0) {
99 #ifdef CONFIG_EISA
100 		mp_bus_id_to_type[m->busid] = MP_BUS_ISA;
101 #endif
102 	} else if (strncmp(str, BUSTYPE_PCI, sizeof(BUSTYPE_PCI) - 1) == 0) {
103 		if (x86_init.mpparse.mpc_oem_pci_bus)
104 			x86_init.mpparse.mpc_oem_pci_bus(m);
105 
106 		clear_bit(m->busid, mp_bus_not_pci);
107 #ifdef CONFIG_EISA
108 		mp_bus_id_to_type[m->busid] = MP_BUS_PCI;
109 	} else if (strncmp(str, BUSTYPE_EISA, sizeof(BUSTYPE_EISA) - 1) == 0) {
110 		mp_bus_id_to_type[m->busid] = MP_BUS_EISA;
111 #endif
112 	} else
113 		pr_warn("Unknown bustype %s - ignoring\n", str);
114 }
115 
116 static void __init MP_ioapic_info(struct mpc_ioapic *m)
117 {
118 	struct ioapic_domain_cfg cfg = {
119 		.type = IOAPIC_DOMAIN_LEGACY,
120 		.ops = &mp_ioapic_irqdomain_ops,
121 	};
122 
123 	if (m->flags & MPC_APIC_USABLE)
124 		mp_register_ioapic(m->apicid, m->apicaddr, gsi_top, &cfg);
125 }
126 
127 static void __init print_mp_irq_info(struct mpc_intsrc *mp_irq)
128 {
129 	apic_printk(APIC_VERBOSE,
130 		"Int: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC INT %02x\n",
131 		mp_irq->irqtype, mp_irq->irqflag & 3,
132 		(mp_irq->irqflag >> 2) & 3, mp_irq->srcbus,
133 		mp_irq->srcbusirq, mp_irq->dstapic, mp_irq->dstirq);
134 }
135 
136 #else /* CONFIG_X86_IO_APIC */
137 static inline void __init MP_bus_info(struct mpc_bus *m) {}
138 static inline void __init MP_ioapic_info(struct mpc_ioapic *m) {}
139 #endif /* CONFIG_X86_IO_APIC */
140 
141 static void __init MP_lintsrc_info(struct mpc_lintsrc *m)
142 {
143 	apic_printk(APIC_VERBOSE,
144 		"Lint: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC LINT %02x\n",
145 		m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbusid,
146 		m->srcbusirq, m->destapic, m->destapiclint);
147 }
148 
149 /*
150  * Read/parse the MPC
151  */
152 static int __init smp_check_mpc(struct mpc_table *mpc, char *oem, char *str)
153 {
154 
155 	if (memcmp(mpc->signature, MPC_SIGNATURE, 4)) {
156 		pr_err("MPTABLE: bad signature [%c%c%c%c]!\n",
157 		       mpc->signature[0], mpc->signature[1],
158 		       mpc->signature[2], mpc->signature[3]);
159 		return 0;
160 	}
161 	if (mpf_checksum((unsigned char *)mpc, mpc->length)) {
162 		pr_err("MPTABLE: checksum error!\n");
163 		return 0;
164 	}
165 	if (mpc->spec != 0x01 && mpc->spec != 0x04) {
166 		pr_err("MPTABLE: bad table version (%d)!!\n", mpc->spec);
167 		return 0;
168 	}
169 	if (!mpc->lapic) {
170 		pr_err("MPTABLE: null local APIC address!\n");
171 		return 0;
172 	}
173 	memcpy(oem, mpc->oem, 8);
174 	oem[8] = 0;
175 	pr_info("MPTABLE: OEM ID: %s\n", oem);
176 
177 	memcpy(str, mpc->productid, 12);
178 	str[12] = 0;
179 
180 	pr_info("MPTABLE: Product ID: %s\n", str);
181 
182 	pr_info("MPTABLE: APIC at: 0x%X\n", mpc->lapic);
183 
184 	return 1;
185 }
186 
187 static void skip_entry(unsigned char **ptr, int *count, int size)
188 {
189 	*ptr += size;
190 	*count += size;
191 }
192 
193 static void __init smp_dump_mptable(struct mpc_table *mpc, unsigned char *mpt)
194 {
195 	pr_err("Your mptable is wrong, contact your HW vendor!\n");
196 	pr_cont("type %x\n", *mpt);
197 	print_hex_dump(KERN_ERR, "  ", DUMP_PREFIX_ADDRESS, 16,
198 			1, mpc, mpc->length, 1);
199 }
200 
201 void __init default_smp_read_mpc_oem(struct mpc_table *mpc) { }
202 
203 static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
204 {
205 	char str[16];
206 	char oem[10];
207 
208 	int count = sizeof(*mpc);
209 	unsigned char *mpt = ((unsigned char *)mpc) + count;
210 
211 	if (!smp_check_mpc(mpc, oem, str))
212 		return 0;
213 
214 	/* Initialize the lapic mapping */
215 	if (!acpi_lapic)
216 		register_lapic_address(mpc->lapic);
217 
218 	if (early)
219 		return 1;
220 
221 	if (mpc->oemptr)
222 		x86_init.mpparse.smp_read_mpc_oem(mpc);
223 
224 	/*
225 	 *      Now process the configuration blocks.
226 	 */
227 	x86_init.mpparse.mpc_record(0);
228 
229 	while (count < mpc->length) {
230 		switch (*mpt) {
231 		case MP_PROCESSOR:
232 			/* ACPI may have already provided this data */
233 			if (!acpi_lapic)
234 				MP_processor_info((struct mpc_cpu *)mpt);
235 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
236 			break;
237 		case MP_BUS:
238 			MP_bus_info((struct mpc_bus *)mpt);
239 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
240 			break;
241 		case MP_IOAPIC:
242 			MP_ioapic_info((struct mpc_ioapic *)mpt);
243 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
244 			break;
245 		case MP_INTSRC:
246 			mp_save_irq((struct mpc_intsrc *)mpt);
247 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
248 			break;
249 		case MP_LINTSRC:
250 			MP_lintsrc_info((struct mpc_lintsrc *)mpt);
251 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
252 			break;
253 		default:
254 			/* wrong mptable */
255 			smp_dump_mptable(mpc, mpt);
256 			count = mpc->length;
257 			break;
258 		}
259 		x86_init.mpparse.mpc_record(1);
260 	}
261 
262 	if (!num_processors)
263 		pr_err("MPTABLE: no processors registered!\n");
264 	return num_processors;
265 }
266 
267 #ifdef CONFIG_X86_IO_APIC
268 
269 static int __init ELCR_trigger(unsigned int irq)
270 {
271 	unsigned int port;
272 
273 	port = 0x4d0 + (irq >> 3);
274 	return (inb(port) >> (irq & 7)) & 1;
275 }
276 
277 static void __init construct_default_ioirq_mptable(int mpc_default_type)
278 {
279 	struct mpc_intsrc intsrc;
280 	int i;
281 	int ELCR_fallback = 0;
282 
283 	intsrc.type = MP_INTSRC;
284 	intsrc.irqflag = 0;	/* conforming */
285 	intsrc.srcbus = 0;
286 	intsrc.dstapic = mpc_ioapic_id(0);
287 
288 	intsrc.irqtype = mp_INT;
289 
290 	/*
291 	 *  If true, we have an ISA/PCI system with no IRQ entries
292 	 *  in the MP table. To prevent the PCI interrupts from being set up
293 	 *  incorrectly, we try to use the ELCR. The sanity check to see if
294 	 *  there is good ELCR data is very simple - IRQ0, 1, 2 and 13 can
295 	 *  never be level sensitive, so we simply see if the ELCR agrees.
296 	 *  If it does, we assume it's valid.
297 	 */
298 	if (mpc_default_type == 5) {
299 		pr_info("ISA/PCI bus type with no IRQ information... falling back to ELCR\n");
300 
301 		if (ELCR_trigger(0) || ELCR_trigger(1) || ELCR_trigger(2) ||
302 		    ELCR_trigger(13))
303 			pr_err("ELCR contains invalid data... not using ELCR\n");
304 		else {
305 			pr_info("Using ELCR to identify PCI interrupts\n");
306 			ELCR_fallback = 1;
307 		}
308 	}
309 
310 	for (i = 0; i < 16; i++) {
311 		switch (mpc_default_type) {
312 		case 2:
313 			if (i == 0 || i == 13)
314 				continue;	/* IRQ0 & IRQ13 not connected */
315 			/* fall through */
316 		default:
317 			if (i == 2)
318 				continue;	/* IRQ2 is never connected */
319 		}
320 
321 		if (ELCR_fallback) {
322 			/*
323 			 *  If the ELCR indicates a level-sensitive interrupt, we
324 			 *  copy that information over to the MP table in the
325 			 *  irqflag field (level sensitive, active high polarity).
326 			 */
327 			if (ELCR_trigger(i))
328 				intsrc.irqflag = 13;
329 			else
330 				intsrc.irqflag = 0;
331 		}
332 
333 		intsrc.srcbusirq = i;
334 		intsrc.dstirq = i ? i : 2;	/* IRQ0 to INTIN2 */
335 		mp_save_irq(&intsrc);
336 	}
337 
338 	intsrc.irqtype = mp_ExtINT;
339 	intsrc.srcbusirq = 0;
340 	intsrc.dstirq = 0;	/* 8259A to INTIN0 */
341 	mp_save_irq(&intsrc);
342 }
343 
344 
345 static void __init construct_ioapic_table(int mpc_default_type)
346 {
347 	struct mpc_ioapic ioapic;
348 	struct mpc_bus bus;
349 
350 	bus.type = MP_BUS;
351 	bus.busid = 0;
352 	switch (mpc_default_type) {
353 	default:
354 		pr_err("???\nUnknown standard configuration %d\n",
355 		       mpc_default_type);
356 		/* fall through */
357 	case 1:
358 	case 5:
359 		memcpy(bus.bustype, "ISA   ", 6);
360 		break;
361 	case 2:
362 	case 6:
363 	case 3:
364 		memcpy(bus.bustype, "EISA  ", 6);
365 		break;
366 	}
367 	MP_bus_info(&bus);
368 	if (mpc_default_type > 4) {
369 		bus.busid = 1;
370 		memcpy(bus.bustype, "PCI   ", 6);
371 		MP_bus_info(&bus);
372 	}
373 
374 	ioapic.type	= MP_IOAPIC;
375 	ioapic.apicid	= 2;
376 	ioapic.apicver	= mpc_default_type > 4 ? 0x10 : 0x01;
377 	ioapic.flags	= MPC_APIC_USABLE;
378 	ioapic.apicaddr	= IO_APIC_DEFAULT_PHYS_BASE;
379 	MP_ioapic_info(&ioapic);
380 
381 	/*
382 	 * We set up most of the low 16 IO-APIC pins according to MPS rules.
383 	 */
384 	construct_default_ioirq_mptable(mpc_default_type);
385 }
386 #else
387 static inline void __init construct_ioapic_table(int mpc_default_type) { }
388 #endif
389 
390 static inline void __init construct_default_ISA_mptable(int mpc_default_type)
391 {
392 	struct mpc_cpu processor;
393 	struct mpc_lintsrc lintsrc;
394 	int linttypes[2] = { mp_ExtINT, mp_NMI };
395 	int i;
396 
397 	/*
398 	 * local APIC has default address
399 	 */
400 	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
401 
402 	/*
403 	 * 2 CPUs, numbered 0 & 1.
404 	 */
405 	processor.type = MP_PROCESSOR;
406 	/* Either an integrated APIC or a discrete 82489DX. */
407 	processor.apicver = mpc_default_type > 4 ? 0x10 : 0x01;
408 	processor.cpuflag = CPU_ENABLED;
409 	processor.cpufeature = (boot_cpu_data.x86 << 8) |
410 	    (boot_cpu_data.x86_model << 4) | boot_cpu_data.x86_mask;
411 	processor.featureflag = boot_cpu_data.x86_capability[CPUID_1_EDX];
412 	processor.reserved[0] = 0;
413 	processor.reserved[1] = 0;
414 	for (i = 0; i < 2; i++) {
415 		processor.apicid = i;
416 		MP_processor_info(&processor);
417 	}
418 
419 	construct_ioapic_table(mpc_default_type);
420 
421 	lintsrc.type = MP_LINTSRC;
422 	lintsrc.irqflag = 0;		/* conforming */
423 	lintsrc.srcbusid = 0;
424 	lintsrc.srcbusirq = 0;
425 	lintsrc.destapic = MP_APIC_ALL;
426 	for (i = 0; i < 2; i++) {
427 		lintsrc.irqtype = linttypes[i];
428 		lintsrc.destapiclint = i;
429 		MP_lintsrc_info(&lintsrc);
430 	}
431 }
432 
433 static unsigned long mpf_base;
434 
435 static unsigned long __init get_mpc_size(unsigned long physptr)
436 {
437 	struct mpc_table *mpc;
438 	unsigned long size;
439 
440 	mpc = early_memremap(physptr, PAGE_SIZE);
441 	size = mpc->length;
442 	early_memunmap(mpc, PAGE_SIZE);
443 	apic_printk(APIC_VERBOSE, "  mpc: %lx-%lx\n", physptr, physptr + size);
444 
445 	return size;
446 }
447 
448 static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
449 {
450 	struct mpc_table *mpc;
451 	unsigned long size;
452 
453 	size = get_mpc_size(mpf->physptr);
454 	mpc = early_memremap(mpf->physptr, size);
455 
456 	/*
457 	 * Read the physical hardware table.  Anything here will
458 	 * override the defaults.
459 	 */
460 	if (!smp_read_mpc(mpc, early)) {
461 #ifdef CONFIG_X86_LOCAL_APIC
462 		smp_found_config = 0;
463 #endif
464 		pr_err("BIOS bug, MP table errors detected!...\n");
465 		pr_cont("... disabling SMP support. (tell your hw vendor)\n");
466 		early_memunmap(mpc, size);
467 		return -1;
468 	}
469 	early_memunmap(mpc, size);
470 
471 	if (early)
472 		return -1;
473 
474 #ifdef CONFIG_X86_IO_APIC
475 	/*
476 	 * If there are no explicit MP IRQ entries, then we are
477 	 * broken.  We set up most of the low 16 IO-APIC pins to
478 	 * ISA defaults and hope it will work.
479 	 */
480 	if (!mp_irq_entries) {
481 		struct mpc_bus bus;
482 
483 		pr_err("BIOS bug, no explicit IRQ entries, using default mptable. (tell your hw vendor)\n");
484 
485 		bus.type = MP_BUS;
486 		bus.busid = 0;
487 		memcpy(bus.bustype, "ISA   ", 6);
488 		MP_bus_info(&bus);
489 
490 		construct_default_ioirq_mptable(0);
491 	}
492 #endif
493 
494 	return 0;
495 }
496 
497 /*
498  * Scan the memory blocks for an SMP configuration block.
499  */
500 void __init default_get_smp_config(unsigned int early)
501 {
502 	struct mpf_intel *mpf;
503 
504 	if (!smp_found_config)
505 		return;
506 
507 	if (!mpf_base)
508 		return;
509 
510 	if (acpi_lapic && early)
511 		return;
512 
513 	/*
514 	 * MPS doesn't support hyperthreading, aka only have
515 	 * thread 0 apic id in MPS table
516 	 */
517 	if (acpi_lapic && acpi_ioapic)
518 		return;
519 
520 	mpf = early_memremap(mpf_base, sizeof(*mpf));
521 	if (!mpf) {
522 		pr_err("MPTABLE: error mapping MP table\n");
523 		return;
524 	}
525 
526 	pr_info("Intel MultiProcessor Specification v1.%d\n",
527 		mpf->specification);
528 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
529 	if (mpf->feature2 & (1 << 7)) {
530 		pr_info("    IMCR and PIC compatibility mode.\n");
531 		pic_mode = 1;
532 	} else {
533 		pr_info("    Virtual Wire compatibility mode.\n");
534 		pic_mode = 0;
535 	}
536 #endif
537 	/*
538 	 * Now see if we need to read further.
539 	 */
540 	if (mpf->feature1) {
541 		if (early) {
542 			/*
543 			 * local APIC has default address
544 			 */
545 			mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
546 			return;
547 		}
548 
549 		pr_info("Default MP configuration #%d\n", mpf->feature1);
550 		construct_default_ISA_mptable(mpf->feature1);
551 
552 	} else if (mpf->physptr) {
553 		if (check_physptr(mpf, early)) {
554 			early_memunmap(mpf, sizeof(*mpf));
555 			return;
556 		}
557 	} else
558 		BUG();
559 
560 	if (!early)
561 		pr_info("Processors: %d\n", num_processors);
562 	/*
563 	 * Only use the first configuration found.
564 	 */
565 
566 	early_memunmap(mpf, sizeof(*mpf));
567 }
568 
569 static void __init smp_reserve_memory(struct mpf_intel *mpf)
570 {
571 	memblock_reserve(mpf->physptr, get_mpc_size(mpf->physptr));
572 }
573 
574 static int __init smp_scan_config(unsigned long base, unsigned long length)
575 {
576 	unsigned int *bp;
577 	struct mpf_intel *mpf;
578 	int ret = 0;
579 
580 	apic_printk(APIC_VERBOSE, "Scan for SMP in [mem %#010lx-%#010lx]\n",
581 		    base, base + length - 1);
582 	BUILD_BUG_ON(sizeof(*mpf) != 16);
583 
584 	while (length > 0) {
585 		bp = early_memremap(base, length);
586 		mpf = (struct mpf_intel *)bp;
587 		if ((*bp == SMP_MAGIC_IDENT) &&
588 		    (mpf->length == 1) &&
589 		    !mpf_checksum((unsigned char *)bp, 16) &&
590 		    ((mpf->specification == 1)
591 		     || (mpf->specification == 4))) {
592 #ifdef CONFIG_X86_LOCAL_APIC
593 			smp_found_config = 1;
594 #endif
595 			mpf_base = base;
596 
597 			pr_info("found SMP MP-table at [mem %#010lx-%#010lx] mapped at [%p]\n",
598 				base, base + sizeof(*mpf) - 1, mpf);
599 
600 			memblock_reserve(base, sizeof(*mpf));
601 			if (mpf->physptr)
602 				smp_reserve_memory(mpf);
603 
604 			ret = 1;
605 		}
606 		early_memunmap(bp, length);
607 
608 		if (ret)
609 			break;
610 
611 		base += 16;
612 		length -= 16;
613 	}
614 	return ret;
615 }
616 
617 void __init default_find_smp_config(void)
618 {
619 	unsigned int address;
620 
621 	/*
622 	 * FIXME: Linux assumes you have 640K of base ram..
623 	 * this continues the error...
624 	 *
625 	 * 1) Scan the bottom 1K for a signature
626 	 * 2) Scan the top 1K of base RAM
627 	 * 3) Scan the 64K of bios
628 	 */
629 	if (smp_scan_config(0x0, 0x400) ||
630 	    smp_scan_config(639 * 0x400, 0x400) ||
631 	    smp_scan_config(0xF0000, 0x10000))
632 		return;
633 	/*
634 	 * If it is an SMP machine we should know now, unless the
635 	 * configuration is in an EISA bus machine with an
636 	 * extended bios data area.
637 	 *
638 	 * there is a real-mode segmented pointer pointing to the
639 	 * 4K EBDA area at 0x40E, calculate and scan it here.
640 	 *
641 	 * NOTE! There are Linux loaders that will corrupt the EBDA
642 	 * area, and as such this kind of SMP config may be less
643 	 * trustworthy, simply because the SMP table may have been
644 	 * stomped on during early boot. These loaders are buggy and
645 	 * should be fixed.
646 	 *
647 	 * MP1.4 SPEC states to only scan first 1K of 4K EBDA.
648 	 */
649 
650 	address = get_bios_ebda();
651 	if (address)
652 		smp_scan_config(address, 0x400);
653 }
654 
655 #ifdef CONFIG_X86_IO_APIC
656 static u8 __initdata irq_used[MAX_IRQ_SOURCES];
657 
658 static int  __init get_MP_intsrc_index(struct mpc_intsrc *m)
659 {
660 	int i;
661 
662 	if (m->irqtype != mp_INT)
663 		return 0;
664 
665 	if (m->irqflag != 0x0f)
666 		return 0;
667 
668 	/* not legacy */
669 
670 	for (i = 0; i < mp_irq_entries; i++) {
671 		if (mp_irqs[i].irqtype != mp_INT)
672 			continue;
673 
674 		if (mp_irqs[i].irqflag != 0x0f)
675 			continue;
676 
677 		if (mp_irqs[i].srcbus != m->srcbus)
678 			continue;
679 		if (mp_irqs[i].srcbusirq != m->srcbusirq)
680 			continue;
681 		if (irq_used[i]) {
682 			/* already claimed */
683 			return -2;
684 		}
685 		irq_used[i] = 1;
686 		return i;
687 	}
688 
689 	/* not found */
690 	return -1;
691 }
692 
693 #define SPARE_SLOT_NUM 20
694 
695 static struct mpc_intsrc __initdata *m_spare[SPARE_SLOT_NUM];
696 
697 static void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare)
698 {
699 	int i;
700 
701 	apic_printk(APIC_VERBOSE, "OLD ");
702 	print_mp_irq_info(m);
703 
704 	i = get_MP_intsrc_index(m);
705 	if (i > 0) {
706 		memcpy(m, &mp_irqs[i], sizeof(*m));
707 		apic_printk(APIC_VERBOSE, "NEW ");
708 		print_mp_irq_info(&mp_irqs[i]);
709 		return;
710 	}
711 	if (!i) {
712 		/* legacy, do nothing */
713 		return;
714 	}
715 	if (*nr_m_spare < SPARE_SLOT_NUM) {
716 		/*
717 		 * not found (-1), or duplicated (-2) are invalid entries,
718 		 * we need to use the slot later
719 		 */
720 		m_spare[*nr_m_spare] = m;
721 		*nr_m_spare += 1;
722 	}
723 }
724 
725 static int __init
726 check_slot(unsigned long mpc_new_phys, unsigned long mpc_new_length, int count)
727 {
728 	if (!mpc_new_phys || count <= mpc_new_length) {
729 		WARN(1, "update_mptable: No spare slots (length: %x)\n", count);
730 		return -1;
731 	}
732 
733 	return 0;
734 }
735 #else /* CONFIG_X86_IO_APIC */
736 static
737 inline void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare) {}
738 #endif /* CONFIG_X86_IO_APIC */
739 
740 static int  __init replace_intsrc_all(struct mpc_table *mpc,
741 					unsigned long mpc_new_phys,
742 					unsigned long mpc_new_length)
743 {
744 #ifdef CONFIG_X86_IO_APIC
745 	int i;
746 #endif
747 	int count = sizeof(*mpc);
748 	int nr_m_spare = 0;
749 	unsigned char *mpt = ((unsigned char *)mpc) + count;
750 
751 	pr_info("mpc_length %x\n", mpc->length);
752 	while (count < mpc->length) {
753 		switch (*mpt) {
754 		case MP_PROCESSOR:
755 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
756 			break;
757 		case MP_BUS:
758 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
759 			break;
760 		case MP_IOAPIC:
761 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
762 			break;
763 		case MP_INTSRC:
764 			check_irq_src((struct mpc_intsrc *)mpt, &nr_m_spare);
765 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
766 			break;
767 		case MP_LINTSRC:
768 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
769 			break;
770 		default:
771 			/* wrong mptable */
772 			smp_dump_mptable(mpc, mpt);
773 			goto out;
774 		}
775 	}
776 
777 #ifdef CONFIG_X86_IO_APIC
778 	for (i = 0; i < mp_irq_entries; i++) {
779 		if (irq_used[i])
780 			continue;
781 
782 		if (mp_irqs[i].irqtype != mp_INT)
783 			continue;
784 
785 		if (mp_irqs[i].irqflag != 0x0f)
786 			continue;
787 
788 		if (nr_m_spare > 0) {
789 			apic_printk(APIC_VERBOSE, "*NEW* found\n");
790 			nr_m_spare--;
791 			memcpy(m_spare[nr_m_spare], &mp_irqs[i], sizeof(mp_irqs[i]));
792 			m_spare[nr_m_spare] = NULL;
793 		} else {
794 			struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
795 			count += sizeof(struct mpc_intsrc);
796 			if (check_slot(mpc_new_phys, mpc_new_length, count) < 0)
797 				goto out;
798 			memcpy(m, &mp_irqs[i], sizeof(*m));
799 			mpc->length = count;
800 			mpt += sizeof(struct mpc_intsrc);
801 		}
802 		print_mp_irq_info(&mp_irqs[i]);
803 	}
804 #endif
805 out:
806 	/* update checksum */
807 	mpc->checksum = 0;
808 	mpc->checksum -= mpf_checksum((unsigned char *)mpc, mpc->length);
809 
810 	return 0;
811 }
812 
813 int enable_update_mptable;
814 
815 static int __init update_mptable_setup(char *str)
816 {
817 	enable_update_mptable = 1;
818 #ifdef CONFIG_PCI
819 	pci_routeirq = 1;
820 #endif
821 	return 0;
822 }
823 early_param("update_mptable", update_mptable_setup);
824 
825 static unsigned long __initdata mpc_new_phys;
826 static unsigned long mpc_new_length __initdata = 4096;
827 
828 /* alloc_mptable or alloc_mptable=4k */
829 static int __initdata alloc_mptable;
830 static int __init parse_alloc_mptable_opt(char *p)
831 {
832 	enable_update_mptable = 1;
833 #ifdef CONFIG_PCI
834 	pci_routeirq = 1;
835 #endif
836 	alloc_mptable = 1;
837 	if (!p)
838 		return 0;
839 	mpc_new_length = memparse(p, &p);
840 	return 0;
841 }
842 early_param("alloc_mptable", parse_alloc_mptable_opt);
843 
844 void __init e820__memblock_alloc_reserved_mpc_new(void)
845 {
846 	if (enable_update_mptable && alloc_mptable)
847 		mpc_new_phys = e820__memblock_alloc_reserved(mpc_new_length, 4);
848 }
849 
850 static int __init update_mp_table(void)
851 {
852 	char str[16];
853 	char oem[10];
854 	struct mpf_intel *mpf;
855 	struct mpc_table *mpc, *mpc_new;
856 	unsigned long size;
857 
858 	if (!enable_update_mptable)
859 		return 0;
860 
861 	if (!mpf_base)
862 		return 0;
863 
864 	mpf = early_memremap(mpf_base, sizeof(*mpf));
865 	if (!mpf) {
866 		pr_err("MPTABLE: mpf early_memremap() failed\n");
867 		return 0;
868 	}
869 
870 	/*
871 	 * Now see if we need to go further.
872 	 */
873 	if (mpf->feature1)
874 		goto do_unmap_mpf;
875 
876 	if (!mpf->physptr)
877 		goto do_unmap_mpf;
878 
879 	size = get_mpc_size(mpf->physptr);
880 	mpc = early_memremap(mpf->physptr, size);
881 	if (!mpc) {
882 		pr_err("MPTABLE: mpc early_memremap() failed\n");
883 		goto do_unmap_mpf;
884 	}
885 
886 	if (!smp_check_mpc(mpc, oem, str))
887 		goto do_unmap_mpc;
888 
889 	pr_info("mpf: %llx\n", (u64)mpf_base);
890 	pr_info("physptr: %x\n", mpf->physptr);
891 
892 	if (mpc_new_phys && mpc->length > mpc_new_length) {
893 		mpc_new_phys = 0;
894 		pr_info("mpc_new_length is %ld, please use alloc_mptable=8k\n",
895 			mpc_new_length);
896 	}
897 
898 	if (!mpc_new_phys) {
899 		unsigned char old, new;
900 		/* check if we can change the position */
901 		mpc->checksum = 0;
902 		old = mpf_checksum((unsigned char *)mpc, mpc->length);
903 		mpc->checksum = 0xff;
904 		new = mpf_checksum((unsigned char *)mpc, mpc->length);
905 		if (old == new) {
906 			pr_info("mpc is readonly, please try alloc_mptable instead\n");
907 			goto do_unmap_mpc;
908 		}
909 		pr_info("use in-position replacing\n");
910 	} else {
911 		mpc_new = early_memremap(mpc_new_phys, mpc_new_length);
912 		if (!mpc_new) {
913 			pr_err("MPTABLE: new mpc early_memremap() failed\n");
914 			goto do_unmap_mpc;
915 		}
916 		mpf->physptr = mpc_new_phys;
917 		memcpy(mpc_new, mpc, mpc->length);
918 		early_memunmap(mpc, size);
919 		mpc = mpc_new;
920 		size = mpc_new_length;
921 		/* check if we can modify that */
922 		if (mpc_new_phys - mpf->physptr) {
923 			struct mpf_intel *mpf_new;
924 			/* steal 16 bytes from [0, 1k) */
925 			mpf_new = early_memremap(0x400 - 16, sizeof(*mpf_new));
926 			if (!mpf_new) {
927 				pr_err("MPTABLE: new mpf early_memremap() failed\n");
928 				goto do_unmap_mpc;
929 			}
930 			pr_info("mpf new: %x\n", 0x400 - 16);
931 			memcpy(mpf_new, mpf, 16);
932 			early_memunmap(mpf, sizeof(*mpf));
933 			mpf = mpf_new;
934 			mpf->physptr = mpc_new_phys;
935 		}
936 		mpf->checksum = 0;
937 		mpf->checksum -= mpf_checksum((unsigned char *)mpf, 16);
938 		pr_info("physptr new: %x\n", mpf->physptr);
939 	}
940 
941 	/*
942 	 * only replace the one with mp_INT and
943 	 *	 MP_IRQ_TRIGGER_LEVEL|MP_IRQ_POLARITY_LOW,
944 	 * already in mp_irqs , stored by ... and mp_config_acpi_gsi,
945 	 * may need pci=routeirq for all coverage
946 	 */
947 	replace_intsrc_all(mpc, mpc_new_phys, mpc_new_length);
948 
949 do_unmap_mpc:
950 	early_memunmap(mpc, size);
951 
952 do_unmap_mpf:
953 	early_memunmap(mpf, sizeof(*mpf));
954 
955 	return 0;
956 }
957 
958 late_initcall(update_mp_table);
959