xref: /openbmc/linux/arch/x86/kernel/mpparse.c (revision 80483c3a)
1 /*
2  *	Intel Multiprocessor Specification 1.1 and 1.4
3  *	compliant MP-table parsing routines.
4  *
5  *	(c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
6  *	(c) 1998, 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com>
7  *      (c) 2008 Alexey Starikovskiy <astarikovskiy@suse.de>
8  */
9 
10 #include <linux/mm.h>
11 #include <linux/init.h>
12 #include <linux/delay.h>
13 #include <linux/bootmem.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/irqdomain.h>
23 #include <asm/mtrr.h>
24 #include <asm/mpspec.h>
25 #include <asm/pgalloc.h>
26 #include <asm/io_apic.h>
27 #include <asm/proto.h>
28 #include <asm/bios_ebda.h>
29 #include <asm/e820.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 int __init default_mpc_apic_id(struct mpc_cpu *m)
49 {
50 	return m->apicid;
51 }
52 
53 static void __init MP_processor_info(struct mpc_cpu *m)
54 {
55 	int apicid;
56 	char *bootup_cpu = "";
57 
58 	if (!(m->cpuflag & CPU_ENABLED)) {
59 		disabled_cpus++;
60 		return;
61 	}
62 
63 	apicid = x86_init.mpparse.mpc_apic_id(m);
64 
65 	if (m->cpuflag & CPU_BOOTPROCESSOR) {
66 		bootup_cpu = " (Bootup-CPU)";
67 		boot_cpu_physical_apicid = m->apicid;
68 	}
69 
70 	pr_info("Processor #%d%s\n", m->apicid, bootup_cpu);
71 	generic_processor_info(apicid, m->apicver);
72 }
73 
74 #ifdef CONFIG_X86_IO_APIC
75 void __init default_mpc_oem_bus_info(struct mpc_bus *m, char *str)
76 {
77 	memcpy(str, m->bustype, 6);
78 	str[6] = 0;
79 	apic_printk(APIC_VERBOSE, "Bus #%d is %s\n", m->busid, str);
80 }
81 
82 static void __init MP_bus_info(struct mpc_bus *m)
83 {
84 	char str[7];
85 
86 	x86_init.mpparse.mpc_oem_bus_info(m, str);
87 
88 #if MAX_MP_BUSSES < 256
89 	if (m->busid >= MAX_MP_BUSSES) {
90 		pr_warn("MP table busid value (%d) for bustype %s is too large, max. supported is %d\n",
91 			m->busid, str, MAX_MP_BUSSES - 1);
92 		return;
93 	}
94 #endif
95 
96 	set_bit(m->busid, mp_bus_not_pci);
97 	if (strncmp(str, BUSTYPE_ISA, sizeof(BUSTYPE_ISA) - 1) == 0) {
98 #ifdef CONFIG_EISA
99 		mp_bus_id_to_type[m->busid] = MP_BUS_ISA;
100 #endif
101 	} else if (strncmp(str, BUSTYPE_PCI, sizeof(BUSTYPE_PCI) - 1) == 0) {
102 		if (x86_init.mpparse.mpc_oem_pci_bus)
103 			x86_init.mpparse.mpc_oem_pci_bus(m);
104 
105 		clear_bit(m->busid, mp_bus_not_pci);
106 #ifdef CONFIG_EISA
107 		mp_bus_id_to_type[m->busid] = MP_BUS_PCI;
108 	} else if (strncmp(str, BUSTYPE_EISA, sizeof(BUSTYPE_EISA) - 1) == 0) {
109 		mp_bus_id_to_type[m->busid] = MP_BUS_EISA;
110 #endif
111 	} else
112 		pr_warn("Unknown bustype %s - ignoring\n", str);
113 }
114 
115 static void __init MP_ioapic_info(struct mpc_ioapic *m)
116 {
117 	struct ioapic_domain_cfg cfg = {
118 		.type = IOAPIC_DOMAIN_LEGACY,
119 		.ops = &mp_ioapic_irqdomain_ops,
120 	};
121 
122 	if (m->flags & MPC_APIC_USABLE)
123 		mp_register_ioapic(m->apicid, m->apicaddr, gsi_top, &cfg);
124 }
125 
126 static void __init print_mp_irq_info(struct mpc_intsrc *mp_irq)
127 {
128 	apic_printk(APIC_VERBOSE,
129 		"Int: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC INT %02x\n",
130 		mp_irq->irqtype, mp_irq->irqflag & 3,
131 		(mp_irq->irqflag >> 2) & 3, mp_irq->srcbus,
132 		mp_irq->srcbusirq, mp_irq->dstapic, mp_irq->dstirq);
133 }
134 
135 #else /* CONFIG_X86_IO_APIC */
136 static inline void __init MP_bus_info(struct mpc_bus *m) {}
137 static inline void __init MP_ioapic_info(struct mpc_ioapic *m) {}
138 #endif /* CONFIG_X86_IO_APIC */
139 
140 static void __init MP_lintsrc_info(struct mpc_lintsrc *m)
141 {
142 	apic_printk(APIC_VERBOSE,
143 		"Lint: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC LINT %02x\n",
144 		m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbusid,
145 		m->srcbusirq, m->destapic, m->destapiclint);
146 }
147 
148 /*
149  * Read/parse the MPC
150  */
151 static int __init smp_check_mpc(struct mpc_table *mpc, char *oem, char *str)
152 {
153 
154 	if (memcmp(mpc->signature, MPC_SIGNATURE, 4)) {
155 		pr_err("MPTABLE: bad signature [%c%c%c%c]!\n",
156 		       mpc->signature[0], mpc->signature[1],
157 		       mpc->signature[2], mpc->signature[3]);
158 		return 0;
159 	}
160 	if (mpf_checksum((unsigned char *)mpc, mpc->length)) {
161 		pr_err("MPTABLE: checksum error!\n");
162 		return 0;
163 	}
164 	if (mpc->spec != 0x01 && mpc->spec != 0x04) {
165 		pr_err("MPTABLE: bad table version (%d)!!\n", mpc->spec);
166 		return 0;
167 	}
168 	if (!mpc->lapic) {
169 		pr_err("MPTABLE: null local APIC address!\n");
170 		return 0;
171 	}
172 	memcpy(oem, mpc->oem, 8);
173 	oem[8] = 0;
174 	pr_info("MPTABLE: OEM ID: %s\n", oem);
175 
176 	memcpy(str, mpc->productid, 12);
177 	str[12] = 0;
178 
179 	pr_info("MPTABLE: Product ID: %s\n", str);
180 
181 	pr_info("MPTABLE: APIC at: 0x%X\n", mpc->lapic);
182 
183 	return 1;
184 }
185 
186 static void skip_entry(unsigned char **ptr, int *count, int size)
187 {
188 	*ptr += size;
189 	*count += size;
190 }
191 
192 static void __init smp_dump_mptable(struct mpc_table *mpc, unsigned char *mpt)
193 {
194 	pr_err("Your mptable is wrong, contact your HW vendor!\n");
195 	pr_cont("type %x\n", *mpt);
196 	print_hex_dump(KERN_ERR, "  ", DUMP_PREFIX_ADDRESS, 16,
197 			1, mpc, mpc->length, 1);
198 }
199 
200 void __init default_smp_read_mpc_oem(struct mpc_table *mpc) { }
201 
202 static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
203 {
204 	char str[16];
205 	char oem[10];
206 
207 	int count = sizeof(*mpc);
208 	unsigned char *mpt = ((unsigned char *)mpc) + count;
209 
210 	if (!smp_check_mpc(mpc, oem, str))
211 		return 0;
212 
213 	/* Initialize the lapic mapping */
214 	if (!acpi_lapic)
215 		register_lapic_address(mpc->lapic);
216 
217 	if (early)
218 		return 1;
219 
220 	if (mpc->oemptr)
221 		x86_init.mpparse.smp_read_mpc_oem(mpc);
222 
223 	/*
224 	 *      Now process the configuration blocks.
225 	 */
226 	x86_init.mpparse.mpc_record(0);
227 
228 	while (count < mpc->length) {
229 		switch (*mpt) {
230 		case MP_PROCESSOR:
231 			/* ACPI may have already provided this data */
232 			if (!acpi_lapic)
233 				MP_processor_info((struct mpc_cpu *)mpt);
234 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
235 			break;
236 		case MP_BUS:
237 			MP_bus_info((struct mpc_bus *)mpt);
238 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
239 			break;
240 		case MP_IOAPIC:
241 			MP_ioapic_info((struct mpc_ioapic *)mpt);
242 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
243 			break;
244 		case MP_INTSRC:
245 			mp_save_irq((struct mpc_intsrc *)mpt);
246 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
247 			break;
248 		case MP_LINTSRC:
249 			MP_lintsrc_info((struct mpc_lintsrc *)mpt);
250 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
251 			break;
252 		default:
253 			/* wrong mptable */
254 			smp_dump_mptable(mpc, mpt);
255 			count = mpc->length;
256 			break;
257 		}
258 		x86_init.mpparse.mpc_record(1);
259 	}
260 
261 	if (!num_processors)
262 		pr_err("MPTABLE: no processors registered!\n");
263 	return num_processors;
264 }
265 
266 #ifdef CONFIG_X86_IO_APIC
267 
268 static int __init ELCR_trigger(unsigned int irq)
269 {
270 	unsigned int port;
271 
272 	port = 0x4d0 + (irq >> 3);
273 	return (inb(port) >> (irq & 7)) & 1;
274 }
275 
276 static void __init construct_default_ioirq_mptable(int mpc_default_type)
277 {
278 	struct mpc_intsrc intsrc;
279 	int i;
280 	int ELCR_fallback = 0;
281 
282 	intsrc.type = MP_INTSRC;
283 	intsrc.irqflag = 0;	/* conforming */
284 	intsrc.srcbus = 0;
285 	intsrc.dstapic = mpc_ioapic_id(0);
286 
287 	intsrc.irqtype = mp_INT;
288 
289 	/*
290 	 *  If true, we have an ISA/PCI system with no IRQ entries
291 	 *  in the MP table. To prevent the PCI interrupts from being set up
292 	 *  incorrectly, we try to use the ELCR. The sanity check to see if
293 	 *  there is good ELCR data is very simple - IRQ0, 1, 2 and 13 can
294 	 *  never be level sensitive, so we simply see if the ELCR agrees.
295 	 *  If it does, we assume it's valid.
296 	 */
297 	if (mpc_default_type == 5) {
298 		pr_info("ISA/PCI bus type with no IRQ information... falling back to ELCR\n");
299 
300 		if (ELCR_trigger(0) || ELCR_trigger(1) || ELCR_trigger(2) ||
301 		    ELCR_trigger(13))
302 			pr_err("ELCR contains invalid data... not using ELCR\n");
303 		else {
304 			pr_info("Using ELCR to identify PCI interrupts\n");
305 			ELCR_fallback = 1;
306 		}
307 	}
308 
309 	for (i = 0; i < 16; i++) {
310 		switch (mpc_default_type) {
311 		case 2:
312 			if (i == 0 || i == 13)
313 				continue;	/* IRQ0 & IRQ13 not connected */
314 			/* fall through */
315 		default:
316 			if (i == 2)
317 				continue;	/* IRQ2 is never connected */
318 		}
319 
320 		if (ELCR_fallback) {
321 			/*
322 			 *  If the ELCR indicates a level-sensitive interrupt, we
323 			 *  copy that information over to the MP table in the
324 			 *  irqflag field (level sensitive, active high polarity).
325 			 */
326 			if (ELCR_trigger(i))
327 				intsrc.irqflag = 13;
328 			else
329 				intsrc.irqflag = 0;
330 		}
331 
332 		intsrc.srcbusirq = i;
333 		intsrc.dstirq = i ? i : 2;	/* IRQ0 to INTIN2 */
334 		mp_save_irq(&intsrc);
335 	}
336 
337 	intsrc.irqtype = mp_ExtINT;
338 	intsrc.srcbusirq = 0;
339 	intsrc.dstirq = 0;	/* 8259A to INTIN0 */
340 	mp_save_irq(&intsrc);
341 }
342 
343 
344 static void __init construct_ioapic_table(int mpc_default_type)
345 {
346 	struct mpc_ioapic ioapic;
347 	struct mpc_bus bus;
348 
349 	bus.type = MP_BUS;
350 	bus.busid = 0;
351 	switch (mpc_default_type) {
352 	default:
353 		pr_err("???\nUnknown standard configuration %d\n",
354 		       mpc_default_type);
355 		/* fall through */
356 	case 1:
357 	case 5:
358 		memcpy(bus.bustype, "ISA   ", 6);
359 		break;
360 	case 2:
361 	case 6:
362 	case 3:
363 		memcpy(bus.bustype, "EISA  ", 6);
364 		break;
365 	}
366 	MP_bus_info(&bus);
367 	if (mpc_default_type > 4) {
368 		bus.busid = 1;
369 		memcpy(bus.bustype, "PCI   ", 6);
370 		MP_bus_info(&bus);
371 	}
372 
373 	ioapic.type	= MP_IOAPIC;
374 	ioapic.apicid	= 2;
375 	ioapic.apicver	= mpc_default_type > 4 ? 0x10 : 0x01;
376 	ioapic.flags	= MPC_APIC_USABLE;
377 	ioapic.apicaddr	= IO_APIC_DEFAULT_PHYS_BASE;
378 	MP_ioapic_info(&ioapic);
379 
380 	/*
381 	 * We set up most of the low 16 IO-APIC pins according to MPS rules.
382 	 */
383 	construct_default_ioirq_mptable(mpc_default_type);
384 }
385 #else
386 static inline void __init construct_ioapic_table(int mpc_default_type) { }
387 #endif
388 
389 static inline void __init construct_default_ISA_mptable(int mpc_default_type)
390 {
391 	struct mpc_cpu processor;
392 	struct mpc_lintsrc lintsrc;
393 	int linttypes[2] = { mp_ExtINT, mp_NMI };
394 	int i;
395 
396 	/*
397 	 * local APIC has default address
398 	 */
399 	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
400 
401 	/*
402 	 * 2 CPUs, numbered 0 & 1.
403 	 */
404 	processor.type = MP_PROCESSOR;
405 	/* Either an integrated APIC or a discrete 82489DX. */
406 	processor.apicver = mpc_default_type > 4 ? 0x10 : 0x01;
407 	processor.cpuflag = CPU_ENABLED;
408 	processor.cpufeature = (boot_cpu_data.x86 << 8) |
409 	    (boot_cpu_data.x86_model << 4) | boot_cpu_data.x86_mask;
410 	processor.featureflag = boot_cpu_data.x86_capability[CPUID_1_EDX];
411 	processor.reserved[0] = 0;
412 	processor.reserved[1] = 0;
413 	for (i = 0; i < 2; i++) {
414 		processor.apicid = i;
415 		MP_processor_info(&processor);
416 	}
417 
418 	construct_ioapic_table(mpc_default_type);
419 
420 	lintsrc.type = MP_LINTSRC;
421 	lintsrc.irqflag = 0;		/* conforming */
422 	lintsrc.srcbusid = 0;
423 	lintsrc.srcbusirq = 0;
424 	lintsrc.destapic = MP_APIC_ALL;
425 	for (i = 0; i < 2; i++) {
426 		lintsrc.irqtype = linttypes[i];
427 		lintsrc.destapiclint = i;
428 		MP_lintsrc_info(&lintsrc);
429 	}
430 }
431 
432 static struct mpf_intel *mpf_found;
433 
434 static unsigned long __init get_mpc_size(unsigned long physptr)
435 {
436 	struct mpc_table *mpc;
437 	unsigned long size;
438 
439 	mpc = early_ioremap(physptr, PAGE_SIZE);
440 	size = mpc->length;
441 	early_iounmap(mpc, PAGE_SIZE);
442 	apic_printk(APIC_VERBOSE, "  mpc: %lx-%lx\n", physptr, physptr + size);
443 
444 	return size;
445 }
446 
447 static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
448 {
449 	struct mpc_table *mpc;
450 	unsigned long size;
451 
452 	size = get_mpc_size(mpf->physptr);
453 	mpc = early_ioremap(mpf->physptr, size);
454 	/*
455 	 * Read the physical hardware table.  Anything here will
456 	 * override the defaults.
457 	 */
458 	if (!smp_read_mpc(mpc, early)) {
459 #ifdef CONFIG_X86_LOCAL_APIC
460 		smp_found_config = 0;
461 #endif
462 		pr_err("BIOS bug, MP table errors detected!...\n");
463 		pr_cont("... disabling SMP support. (tell your hw vendor)\n");
464 		early_iounmap(mpc, size);
465 		return -1;
466 	}
467 	early_iounmap(mpc, size);
468 
469 	if (early)
470 		return -1;
471 
472 #ifdef CONFIG_X86_IO_APIC
473 	/*
474 	 * If there are no explicit MP IRQ entries, then we are
475 	 * broken.  We set up most of the low 16 IO-APIC pins to
476 	 * ISA defaults and hope it will work.
477 	 */
478 	if (!mp_irq_entries) {
479 		struct mpc_bus bus;
480 
481 		pr_err("BIOS bug, no explicit IRQ entries, using default mptable. (tell your hw vendor)\n");
482 
483 		bus.type = MP_BUS;
484 		bus.busid = 0;
485 		memcpy(bus.bustype, "ISA   ", 6);
486 		MP_bus_info(&bus);
487 
488 		construct_default_ioirq_mptable(0);
489 	}
490 #endif
491 
492 	return 0;
493 }
494 
495 /*
496  * Scan the memory blocks for an SMP configuration block.
497  */
498 void __init default_get_smp_config(unsigned int early)
499 {
500 	struct mpf_intel *mpf = mpf_found;
501 
502 	if (!mpf)
503 		return;
504 
505 	if (acpi_lapic && early)
506 		return;
507 
508 	/*
509 	 * MPS doesn't support hyperthreading, aka only have
510 	 * thread 0 apic id in MPS table
511 	 */
512 	if (acpi_lapic && acpi_ioapic)
513 		return;
514 
515 	pr_info("Intel MultiProcessor Specification v1.%d\n",
516 		mpf->specification);
517 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
518 	if (mpf->feature2 & (1 << 7)) {
519 		pr_info("    IMCR and PIC compatibility mode.\n");
520 		pic_mode = 1;
521 	} else {
522 		pr_info("    Virtual Wire compatibility mode.\n");
523 		pic_mode = 0;
524 	}
525 #endif
526 	/*
527 	 * Now see if we need to read further.
528 	 */
529 	if (mpf->feature1 != 0) {
530 		if (early) {
531 			/*
532 			 * local APIC has default address
533 			 */
534 			mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
535 			return;
536 		}
537 
538 		pr_info("Default MP configuration #%d\n", mpf->feature1);
539 		construct_default_ISA_mptable(mpf->feature1);
540 
541 	} else if (mpf->physptr) {
542 		if (check_physptr(mpf, early))
543 			return;
544 	} else
545 		BUG();
546 
547 	if (!early)
548 		pr_info("Processors: %d\n", num_processors);
549 	/*
550 	 * Only use the first configuration found.
551 	 */
552 }
553 
554 static void __init smp_reserve_memory(struct mpf_intel *mpf)
555 {
556 	memblock_reserve(mpf->physptr, get_mpc_size(mpf->physptr));
557 }
558 
559 static int __init smp_scan_config(unsigned long base, unsigned long length)
560 {
561 	unsigned int *bp = phys_to_virt(base);
562 	struct mpf_intel *mpf;
563 	unsigned long mem;
564 
565 	apic_printk(APIC_VERBOSE, "Scan for SMP in [mem %#010lx-%#010lx]\n",
566 		    base, base + length - 1);
567 	BUILD_BUG_ON(sizeof(*mpf) != 16);
568 
569 	while (length > 0) {
570 		mpf = (struct mpf_intel *)bp;
571 		if ((*bp == SMP_MAGIC_IDENT) &&
572 		    (mpf->length == 1) &&
573 		    !mpf_checksum((unsigned char *)bp, 16) &&
574 		    ((mpf->specification == 1)
575 		     || (mpf->specification == 4))) {
576 #ifdef CONFIG_X86_LOCAL_APIC
577 			smp_found_config = 1;
578 #endif
579 			mpf_found = mpf;
580 
581 			pr_info("found SMP MP-table at [mem %#010llx-%#010llx] mapped at [%p]\n",
582 				(unsigned long long) virt_to_phys(mpf),
583 				(unsigned long long) virt_to_phys(mpf) +
584 				sizeof(*mpf) - 1, mpf);
585 
586 			mem = virt_to_phys(mpf);
587 			memblock_reserve(mem, sizeof(*mpf));
588 			if (mpf->physptr)
589 				smp_reserve_memory(mpf);
590 
591 			return 1;
592 		}
593 		bp += 4;
594 		length -= 16;
595 	}
596 	return 0;
597 }
598 
599 void __init default_find_smp_config(void)
600 {
601 	unsigned int address;
602 
603 	/*
604 	 * FIXME: Linux assumes you have 640K of base ram..
605 	 * this continues the error...
606 	 *
607 	 * 1) Scan the bottom 1K for a signature
608 	 * 2) Scan the top 1K of base RAM
609 	 * 3) Scan the 64K of bios
610 	 */
611 	if (smp_scan_config(0x0, 0x400) ||
612 	    smp_scan_config(639 * 0x400, 0x400) ||
613 	    smp_scan_config(0xF0000, 0x10000))
614 		return;
615 	/*
616 	 * If it is an SMP machine we should know now, unless the
617 	 * configuration is in an EISA bus machine with an
618 	 * extended bios data area.
619 	 *
620 	 * there is a real-mode segmented pointer pointing to the
621 	 * 4K EBDA area at 0x40E, calculate and scan it here.
622 	 *
623 	 * NOTE! There are Linux loaders that will corrupt the EBDA
624 	 * area, and as such this kind of SMP config may be less
625 	 * trustworthy, simply because the SMP table may have been
626 	 * stomped on during early boot. These loaders are buggy and
627 	 * should be fixed.
628 	 *
629 	 * MP1.4 SPEC states to only scan first 1K of 4K EBDA.
630 	 */
631 
632 	address = get_bios_ebda();
633 	if (address)
634 		smp_scan_config(address, 0x400);
635 }
636 
637 #ifdef CONFIG_X86_IO_APIC
638 static u8 __initdata irq_used[MAX_IRQ_SOURCES];
639 
640 static int  __init get_MP_intsrc_index(struct mpc_intsrc *m)
641 {
642 	int i;
643 
644 	if (m->irqtype != mp_INT)
645 		return 0;
646 
647 	if (m->irqflag != 0x0f)
648 		return 0;
649 
650 	/* not legacy */
651 
652 	for (i = 0; i < mp_irq_entries; i++) {
653 		if (mp_irqs[i].irqtype != mp_INT)
654 			continue;
655 
656 		if (mp_irqs[i].irqflag != 0x0f)
657 			continue;
658 
659 		if (mp_irqs[i].srcbus != m->srcbus)
660 			continue;
661 		if (mp_irqs[i].srcbusirq != m->srcbusirq)
662 			continue;
663 		if (irq_used[i]) {
664 			/* already claimed */
665 			return -2;
666 		}
667 		irq_used[i] = 1;
668 		return i;
669 	}
670 
671 	/* not found */
672 	return -1;
673 }
674 
675 #define SPARE_SLOT_NUM 20
676 
677 static struct mpc_intsrc __initdata *m_spare[SPARE_SLOT_NUM];
678 
679 static void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare)
680 {
681 	int i;
682 
683 	apic_printk(APIC_VERBOSE, "OLD ");
684 	print_mp_irq_info(m);
685 
686 	i = get_MP_intsrc_index(m);
687 	if (i > 0) {
688 		memcpy(m, &mp_irqs[i], sizeof(*m));
689 		apic_printk(APIC_VERBOSE, "NEW ");
690 		print_mp_irq_info(&mp_irqs[i]);
691 		return;
692 	}
693 	if (!i) {
694 		/* legacy, do nothing */
695 		return;
696 	}
697 	if (*nr_m_spare < SPARE_SLOT_NUM) {
698 		/*
699 		 * not found (-1), or duplicated (-2) are invalid entries,
700 		 * we need to use the slot later
701 		 */
702 		m_spare[*nr_m_spare] = m;
703 		*nr_m_spare += 1;
704 	}
705 }
706 
707 static int __init
708 check_slot(unsigned long mpc_new_phys, unsigned long mpc_new_length, int count)
709 {
710 	if (!mpc_new_phys || count <= mpc_new_length) {
711 		WARN(1, "update_mptable: No spare slots (length: %x)\n", count);
712 		return -1;
713 	}
714 
715 	return 0;
716 }
717 #else /* CONFIG_X86_IO_APIC */
718 static
719 inline void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare) {}
720 #endif /* CONFIG_X86_IO_APIC */
721 
722 static int  __init replace_intsrc_all(struct mpc_table *mpc,
723 					unsigned long mpc_new_phys,
724 					unsigned long mpc_new_length)
725 {
726 #ifdef CONFIG_X86_IO_APIC
727 	int i;
728 #endif
729 	int count = sizeof(*mpc);
730 	int nr_m_spare = 0;
731 	unsigned char *mpt = ((unsigned char *)mpc) + count;
732 
733 	pr_info("mpc_length %x\n", mpc->length);
734 	while (count < mpc->length) {
735 		switch (*mpt) {
736 		case MP_PROCESSOR:
737 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
738 			break;
739 		case MP_BUS:
740 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
741 			break;
742 		case MP_IOAPIC:
743 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
744 			break;
745 		case MP_INTSRC:
746 			check_irq_src((struct mpc_intsrc *)mpt, &nr_m_spare);
747 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
748 			break;
749 		case MP_LINTSRC:
750 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
751 			break;
752 		default:
753 			/* wrong mptable */
754 			smp_dump_mptable(mpc, mpt);
755 			goto out;
756 		}
757 	}
758 
759 #ifdef CONFIG_X86_IO_APIC
760 	for (i = 0; i < mp_irq_entries; i++) {
761 		if (irq_used[i])
762 			continue;
763 
764 		if (mp_irqs[i].irqtype != mp_INT)
765 			continue;
766 
767 		if (mp_irqs[i].irqflag != 0x0f)
768 			continue;
769 
770 		if (nr_m_spare > 0) {
771 			apic_printk(APIC_VERBOSE, "*NEW* found\n");
772 			nr_m_spare--;
773 			memcpy(m_spare[nr_m_spare], &mp_irqs[i], sizeof(mp_irqs[i]));
774 			m_spare[nr_m_spare] = NULL;
775 		} else {
776 			struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
777 			count += sizeof(struct mpc_intsrc);
778 			if (check_slot(mpc_new_phys, mpc_new_length, count) < 0)
779 				goto out;
780 			memcpy(m, &mp_irqs[i], sizeof(*m));
781 			mpc->length = count;
782 			mpt += sizeof(struct mpc_intsrc);
783 		}
784 		print_mp_irq_info(&mp_irqs[i]);
785 	}
786 #endif
787 out:
788 	/* update checksum */
789 	mpc->checksum = 0;
790 	mpc->checksum -= mpf_checksum((unsigned char *)mpc, mpc->length);
791 
792 	return 0;
793 }
794 
795 int enable_update_mptable;
796 
797 static int __init update_mptable_setup(char *str)
798 {
799 	enable_update_mptable = 1;
800 #ifdef CONFIG_PCI
801 	pci_routeirq = 1;
802 #endif
803 	return 0;
804 }
805 early_param("update_mptable", update_mptable_setup);
806 
807 static unsigned long __initdata mpc_new_phys;
808 static unsigned long mpc_new_length __initdata = 4096;
809 
810 /* alloc_mptable or alloc_mptable=4k */
811 static int __initdata alloc_mptable;
812 static int __init parse_alloc_mptable_opt(char *p)
813 {
814 	enable_update_mptable = 1;
815 #ifdef CONFIG_PCI
816 	pci_routeirq = 1;
817 #endif
818 	alloc_mptable = 1;
819 	if (!p)
820 		return 0;
821 	mpc_new_length = memparse(p, &p);
822 	return 0;
823 }
824 early_param("alloc_mptable", parse_alloc_mptable_opt);
825 
826 void __init early_reserve_e820_mpc_new(void)
827 {
828 	if (enable_update_mptable && alloc_mptable)
829 		mpc_new_phys = early_reserve_e820(mpc_new_length, 4);
830 }
831 
832 static int __init update_mp_table(void)
833 {
834 	char str[16];
835 	char oem[10];
836 	struct mpf_intel *mpf;
837 	struct mpc_table *mpc, *mpc_new;
838 
839 	if (!enable_update_mptable)
840 		return 0;
841 
842 	mpf = mpf_found;
843 	if (!mpf)
844 		return 0;
845 
846 	/*
847 	 * Now see if we need to go further.
848 	 */
849 	if (mpf->feature1 != 0)
850 		return 0;
851 
852 	if (!mpf->physptr)
853 		return 0;
854 
855 	mpc = phys_to_virt(mpf->physptr);
856 
857 	if (!smp_check_mpc(mpc, oem, str))
858 		return 0;
859 
860 	pr_info("mpf: %llx\n", (u64)virt_to_phys(mpf));
861 	pr_info("physptr: %x\n", mpf->physptr);
862 
863 	if (mpc_new_phys && mpc->length > mpc_new_length) {
864 		mpc_new_phys = 0;
865 		pr_info("mpc_new_length is %ld, please use alloc_mptable=8k\n",
866 			mpc_new_length);
867 	}
868 
869 	if (!mpc_new_phys) {
870 		unsigned char old, new;
871 		/* check if we can change the position */
872 		mpc->checksum = 0;
873 		old = mpf_checksum((unsigned char *)mpc, mpc->length);
874 		mpc->checksum = 0xff;
875 		new = mpf_checksum((unsigned char *)mpc, mpc->length);
876 		if (old == new) {
877 			pr_info("mpc is readonly, please try alloc_mptable instead\n");
878 			return 0;
879 		}
880 		pr_info("use in-position replacing\n");
881 	} else {
882 		mpf->physptr = mpc_new_phys;
883 		mpc_new = phys_to_virt(mpc_new_phys);
884 		memcpy(mpc_new, mpc, mpc->length);
885 		mpc = mpc_new;
886 		/* check if we can modify that */
887 		if (mpc_new_phys - mpf->physptr) {
888 			struct mpf_intel *mpf_new;
889 			/* steal 16 bytes from [0, 1k) */
890 			pr_info("mpf new: %x\n", 0x400 - 16);
891 			mpf_new = phys_to_virt(0x400 - 16);
892 			memcpy(mpf_new, mpf, 16);
893 			mpf = mpf_new;
894 			mpf->physptr = mpc_new_phys;
895 		}
896 		mpf->checksum = 0;
897 		mpf->checksum -= mpf_checksum((unsigned char *)mpf, 16);
898 		pr_info("physptr new: %x\n", mpf->physptr);
899 	}
900 
901 	/*
902 	 * only replace the one with mp_INT and
903 	 *	 MP_IRQ_TRIGGER_LEVEL|MP_IRQ_POLARITY_LOW,
904 	 * already in mp_irqs , stored by ... and mp_config_acpi_gsi,
905 	 * may need pci=routeirq for all coverage
906 	 */
907 	replace_intsrc_all(mpc, mpc_new_phys, mpc_new_length);
908 
909 	return 0;
910 }
911 
912 late_initcall(update_mp_table);
913