xref: /linux/arch/x86/kernel/mpparse.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
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/module.h>
20 #include <linux/smp.h>
21 #include <linux/pci.h>
22 #include <linux/irqdomain.h>
23 
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.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 struct irq_domain_ops mp_ioapic_irqdomain_ops = {
117 	.map = mp_irqdomain_map,
118 	.unmap = mp_irqdomain_unmap,
119 };
120 
121 static void __init MP_ioapic_info(struct mpc_ioapic *m)
122 {
123 	struct ioapic_domain_cfg cfg = {
124 		.type = IOAPIC_DOMAIN_LEGACY,
125 		.ops = &mp_ioapic_irqdomain_ops,
126 	};
127 
128 	if (m->flags & MPC_APIC_USABLE)
129 		mp_register_ioapic(m->apicid, m->apicaddr, gsi_top, &cfg);
130 }
131 
132 static void __init print_mp_irq_info(struct mpc_intsrc *mp_irq)
133 {
134 	apic_printk(APIC_VERBOSE,
135 		"Int: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC INT %02x\n",
136 		mp_irq->irqtype, mp_irq->irqflag & 3,
137 		(mp_irq->irqflag >> 2) & 3, mp_irq->srcbus,
138 		mp_irq->srcbusirq, mp_irq->dstapic, mp_irq->dstirq);
139 }
140 
141 #else /* CONFIG_X86_IO_APIC */
142 static inline void __init MP_bus_info(struct mpc_bus *m) {}
143 static inline void __init MP_ioapic_info(struct mpc_ioapic *m) {}
144 #endif /* CONFIG_X86_IO_APIC */
145 
146 static void __init MP_lintsrc_info(struct mpc_lintsrc *m)
147 {
148 	apic_printk(APIC_VERBOSE,
149 		"Lint: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC LINT %02x\n",
150 		m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbusid,
151 		m->srcbusirq, m->destapic, m->destapiclint);
152 }
153 
154 /*
155  * Read/parse the MPC
156  */
157 static int __init smp_check_mpc(struct mpc_table *mpc, char *oem, char *str)
158 {
159 
160 	if (memcmp(mpc->signature, MPC_SIGNATURE, 4)) {
161 		pr_err("MPTABLE: bad signature [%c%c%c%c]!\n",
162 		       mpc->signature[0], mpc->signature[1],
163 		       mpc->signature[2], mpc->signature[3]);
164 		return 0;
165 	}
166 	if (mpf_checksum((unsigned char *)mpc, mpc->length)) {
167 		pr_err("MPTABLE: checksum error!\n");
168 		return 0;
169 	}
170 	if (mpc->spec != 0x01 && mpc->spec != 0x04) {
171 		pr_err("MPTABLE: bad table version (%d)!!\n", mpc->spec);
172 		return 0;
173 	}
174 	if (!mpc->lapic) {
175 		pr_err("MPTABLE: null local APIC address!\n");
176 		return 0;
177 	}
178 	memcpy(oem, mpc->oem, 8);
179 	oem[8] = 0;
180 	pr_info("MPTABLE: OEM ID: %s\n", oem);
181 
182 	memcpy(str, mpc->productid, 12);
183 	str[12] = 0;
184 
185 	pr_info("MPTABLE: Product ID: %s\n", str);
186 
187 	pr_info("MPTABLE: APIC at: 0x%X\n", mpc->lapic);
188 
189 	return 1;
190 }
191 
192 static void skip_entry(unsigned char **ptr, int *count, int size)
193 {
194 	*ptr += size;
195 	*count += size;
196 }
197 
198 static void __init smp_dump_mptable(struct mpc_table *mpc, unsigned char *mpt)
199 {
200 	pr_err("Your mptable is wrong, contact your HW vendor!\n");
201 	pr_cont("type %x\n", *mpt);
202 	print_hex_dump(KERN_ERR, "  ", DUMP_PREFIX_ADDRESS, 16,
203 			1, mpc, mpc->length, 1);
204 }
205 
206 void __init default_smp_read_mpc_oem(struct mpc_table *mpc) { }
207 
208 static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
209 {
210 	char str[16];
211 	char oem[10];
212 
213 	int count = sizeof(*mpc);
214 	unsigned char *mpt = ((unsigned char *)mpc) + count;
215 
216 	if (!smp_check_mpc(mpc, oem, str))
217 		return 0;
218 
219 	/* Initialize the lapic mapping */
220 	if (!acpi_lapic)
221 		register_lapic_address(mpc->lapic);
222 
223 	if (early)
224 		return 1;
225 
226 	if (mpc->oemptr)
227 		x86_init.mpparse.smp_read_mpc_oem(mpc);
228 
229 	/*
230 	 *      Now process the configuration blocks.
231 	 */
232 	x86_init.mpparse.mpc_record(0);
233 
234 	while (count < mpc->length) {
235 		switch (*mpt) {
236 		case MP_PROCESSOR:
237 			/* ACPI may have already provided this data */
238 			if (!acpi_lapic)
239 				MP_processor_info((struct mpc_cpu *)mpt);
240 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
241 			break;
242 		case MP_BUS:
243 			MP_bus_info((struct mpc_bus *)mpt);
244 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
245 			break;
246 		case MP_IOAPIC:
247 			MP_ioapic_info((struct mpc_ioapic *)mpt);
248 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
249 			break;
250 		case MP_INTSRC:
251 			mp_save_irq((struct mpc_intsrc *)mpt);
252 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
253 			break;
254 		case MP_LINTSRC:
255 			MP_lintsrc_info((struct mpc_lintsrc *)mpt);
256 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
257 			break;
258 		default:
259 			/* wrong mptable */
260 			smp_dump_mptable(mpc, mpt);
261 			count = mpc->length;
262 			break;
263 		}
264 		x86_init.mpparse.mpc_record(1);
265 	}
266 
267 	if (!num_processors)
268 		pr_err("MPTABLE: no processors registered!\n");
269 	return num_processors;
270 }
271 
272 #ifdef CONFIG_X86_IO_APIC
273 
274 static int __init ELCR_trigger(unsigned int irq)
275 {
276 	unsigned int port;
277 
278 	port = 0x4d0 + (irq >> 3);
279 	return (inb(port) >> (irq & 7)) & 1;
280 }
281 
282 static void __init construct_default_ioirq_mptable(int mpc_default_type)
283 {
284 	struct mpc_intsrc intsrc;
285 	int i;
286 	int ELCR_fallback = 0;
287 
288 	intsrc.type = MP_INTSRC;
289 	intsrc.irqflag = 0;	/* conforming */
290 	intsrc.srcbus = 0;
291 	intsrc.dstapic = mpc_ioapic_id(0);
292 
293 	intsrc.irqtype = mp_INT;
294 
295 	/*
296 	 *  If true, we have an ISA/PCI system with no IRQ entries
297 	 *  in the MP table. To prevent the PCI interrupts from being set up
298 	 *  incorrectly, we try to use the ELCR. The sanity check to see if
299 	 *  there is good ELCR data is very simple - IRQ0, 1, 2 and 13 can
300 	 *  never be level sensitive, so we simply see if the ELCR agrees.
301 	 *  If it does, we assume it's valid.
302 	 */
303 	if (mpc_default_type == 5) {
304 		pr_info("ISA/PCI bus type with no IRQ information... falling back to ELCR\n");
305 
306 		if (ELCR_trigger(0) || ELCR_trigger(1) || ELCR_trigger(2) ||
307 		    ELCR_trigger(13))
308 			pr_err("ELCR contains invalid data... not using ELCR\n");
309 		else {
310 			pr_info("Using ELCR to identify PCI interrupts\n");
311 			ELCR_fallback = 1;
312 		}
313 	}
314 
315 	for (i = 0; i < 16; i++) {
316 		switch (mpc_default_type) {
317 		case 2:
318 			if (i == 0 || i == 13)
319 				continue;	/* IRQ0 & IRQ13 not connected */
320 			/* fall through */
321 		default:
322 			if (i == 2)
323 				continue;	/* IRQ2 is never connected */
324 		}
325 
326 		if (ELCR_fallback) {
327 			/*
328 			 *  If the ELCR indicates a level-sensitive interrupt, we
329 			 *  copy that information over to the MP table in the
330 			 *  irqflag field (level sensitive, active high polarity).
331 			 */
332 			if (ELCR_trigger(i))
333 				intsrc.irqflag = 13;
334 			else
335 				intsrc.irqflag = 0;
336 		}
337 
338 		intsrc.srcbusirq = i;
339 		intsrc.dstirq = i ? i : 2;	/* IRQ0 to INTIN2 */
340 		mp_save_irq(&intsrc);
341 	}
342 
343 	intsrc.irqtype = mp_ExtINT;
344 	intsrc.srcbusirq = 0;
345 	intsrc.dstirq = 0;	/* 8259A to INTIN0 */
346 	mp_save_irq(&intsrc);
347 }
348 
349 
350 static void __init construct_ioapic_table(int mpc_default_type)
351 {
352 	struct mpc_ioapic ioapic;
353 	struct mpc_bus bus;
354 
355 	bus.type = MP_BUS;
356 	bus.busid = 0;
357 	switch (mpc_default_type) {
358 	default:
359 		pr_err("???\nUnknown standard configuration %d\n",
360 		       mpc_default_type);
361 		/* fall through */
362 	case 1:
363 	case 5:
364 		memcpy(bus.bustype, "ISA   ", 6);
365 		break;
366 	case 2:
367 	case 6:
368 	case 3:
369 		memcpy(bus.bustype, "EISA  ", 6);
370 		break;
371 	}
372 	MP_bus_info(&bus);
373 	if (mpc_default_type > 4) {
374 		bus.busid = 1;
375 		memcpy(bus.bustype, "PCI   ", 6);
376 		MP_bus_info(&bus);
377 	}
378 
379 	ioapic.type	= MP_IOAPIC;
380 	ioapic.apicid	= 2;
381 	ioapic.apicver	= mpc_default_type > 4 ? 0x10 : 0x01;
382 	ioapic.flags	= MPC_APIC_USABLE;
383 	ioapic.apicaddr	= IO_APIC_DEFAULT_PHYS_BASE;
384 	MP_ioapic_info(&ioapic);
385 
386 	/*
387 	 * We set up most of the low 16 IO-APIC pins according to MPS rules.
388 	 */
389 	construct_default_ioirq_mptable(mpc_default_type);
390 }
391 #else
392 static inline void __init construct_ioapic_table(int mpc_default_type) { }
393 #endif
394 
395 static inline void __init construct_default_ISA_mptable(int mpc_default_type)
396 {
397 	struct mpc_cpu processor;
398 	struct mpc_lintsrc lintsrc;
399 	int linttypes[2] = { mp_ExtINT, mp_NMI };
400 	int i;
401 
402 	/*
403 	 * local APIC has default address
404 	 */
405 	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
406 
407 	/*
408 	 * 2 CPUs, numbered 0 & 1.
409 	 */
410 	processor.type = MP_PROCESSOR;
411 	/* Either an integrated APIC or a discrete 82489DX. */
412 	processor.apicver = mpc_default_type > 4 ? 0x10 : 0x01;
413 	processor.cpuflag = CPU_ENABLED;
414 	processor.cpufeature = (boot_cpu_data.x86 << 8) |
415 	    (boot_cpu_data.x86_model << 4) | boot_cpu_data.x86_mask;
416 	processor.featureflag = boot_cpu_data.x86_capability[0];
417 	processor.reserved[0] = 0;
418 	processor.reserved[1] = 0;
419 	for (i = 0; i < 2; i++) {
420 		processor.apicid = i;
421 		MP_processor_info(&processor);
422 	}
423 
424 	construct_ioapic_table(mpc_default_type);
425 
426 	lintsrc.type = MP_LINTSRC;
427 	lintsrc.irqflag = 0;		/* conforming */
428 	lintsrc.srcbusid = 0;
429 	lintsrc.srcbusirq = 0;
430 	lintsrc.destapic = MP_APIC_ALL;
431 	for (i = 0; i < 2; i++) {
432 		lintsrc.irqtype = linttypes[i];
433 		lintsrc.destapiclint = i;
434 		MP_lintsrc_info(&lintsrc);
435 	}
436 }
437 
438 static struct mpf_intel *mpf_found;
439 
440 static unsigned long __init get_mpc_size(unsigned long physptr)
441 {
442 	struct mpc_table *mpc;
443 	unsigned long size;
444 
445 	mpc = early_ioremap(physptr, PAGE_SIZE);
446 	size = mpc->length;
447 	early_iounmap(mpc, PAGE_SIZE);
448 	apic_printk(APIC_VERBOSE, "  mpc: %lx-%lx\n", physptr, physptr + size);
449 
450 	return size;
451 }
452 
453 static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
454 {
455 	struct mpc_table *mpc;
456 	unsigned long size;
457 
458 	size = get_mpc_size(mpf->physptr);
459 	mpc = early_ioremap(mpf->physptr, size);
460 	/*
461 	 * Read the physical hardware table.  Anything here will
462 	 * override the defaults.
463 	 */
464 	if (!smp_read_mpc(mpc, early)) {
465 #ifdef CONFIG_X86_LOCAL_APIC
466 		smp_found_config = 0;
467 #endif
468 		pr_err("BIOS bug, MP table errors detected!...\n");
469 		pr_cont("... disabling SMP support. (tell your hw vendor)\n");
470 		early_iounmap(mpc, size);
471 		return -1;
472 	}
473 	early_iounmap(mpc, size);
474 
475 	if (early)
476 		return -1;
477 
478 #ifdef CONFIG_X86_IO_APIC
479 	/*
480 	 * If there are no explicit MP IRQ entries, then we are
481 	 * broken.  We set up most of the low 16 IO-APIC pins to
482 	 * ISA defaults and hope it will work.
483 	 */
484 	if (!mp_irq_entries) {
485 		struct mpc_bus bus;
486 
487 		pr_err("BIOS bug, no explicit IRQ entries, using default mptable. (tell your hw vendor)\n");
488 
489 		bus.type = MP_BUS;
490 		bus.busid = 0;
491 		memcpy(bus.bustype, "ISA   ", 6);
492 		MP_bus_info(&bus);
493 
494 		construct_default_ioirq_mptable(0);
495 	}
496 #endif
497 
498 	return 0;
499 }
500 
501 /*
502  * Scan the memory blocks for an SMP configuration block.
503  */
504 void __init default_get_smp_config(unsigned int early)
505 {
506 	struct mpf_intel *mpf = mpf_found;
507 
508 	if (!mpf)
509 		return;
510 
511 	if (acpi_lapic && early)
512 		return;
513 
514 	/*
515 	 * MPS doesn't support hyperthreading, aka only have
516 	 * thread 0 apic id in MPS table
517 	 */
518 	if (acpi_lapic && acpi_ioapic)
519 		return;
520 
521 	pr_info("Intel MultiProcessor Specification v1.%d\n",
522 		mpf->specification);
523 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
524 	if (mpf->feature2 & (1 << 7)) {
525 		pr_info("    IMCR and PIC compatibility mode.\n");
526 		pic_mode = 1;
527 	} else {
528 		pr_info("    Virtual Wire compatibility mode.\n");
529 		pic_mode = 0;
530 	}
531 #endif
532 	/*
533 	 * Now see if we need to read further.
534 	 */
535 	if (mpf->feature1 != 0) {
536 		if (early) {
537 			/*
538 			 * local APIC has default address
539 			 */
540 			mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
541 			return;
542 		}
543 
544 		pr_info("Default MP configuration #%d\n", mpf->feature1);
545 		construct_default_ISA_mptable(mpf->feature1);
546 
547 	} else if (mpf->physptr) {
548 		if (check_physptr(mpf, early))
549 			return;
550 	} else
551 		BUG();
552 
553 	if (!early)
554 		pr_info("Processors: %d\n", num_processors);
555 	/*
556 	 * Only use the first configuration found.
557 	 */
558 }
559 
560 static void __init smp_reserve_memory(struct mpf_intel *mpf)
561 {
562 	memblock_reserve(mpf->physptr, get_mpc_size(mpf->physptr));
563 }
564 
565 static int __init smp_scan_config(unsigned long base, unsigned long length)
566 {
567 	unsigned int *bp = phys_to_virt(base);
568 	struct mpf_intel *mpf;
569 	unsigned long mem;
570 
571 	apic_printk(APIC_VERBOSE, "Scan for SMP in [mem %#010lx-%#010lx]\n",
572 		    base, base + length - 1);
573 	BUILD_BUG_ON(sizeof(*mpf) != 16);
574 
575 	while (length > 0) {
576 		mpf = (struct mpf_intel *)bp;
577 		if ((*bp == SMP_MAGIC_IDENT) &&
578 		    (mpf->length == 1) &&
579 		    !mpf_checksum((unsigned char *)bp, 16) &&
580 		    ((mpf->specification == 1)
581 		     || (mpf->specification == 4))) {
582 #ifdef CONFIG_X86_LOCAL_APIC
583 			smp_found_config = 1;
584 #endif
585 			mpf_found = mpf;
586 
587 			pr_info("found SMP MP-table at [mem %#010llx-%#010llx] mapped at [%p]\n",
588 				(unsigned long long) virt_to_phys(mpf),
589 				(unsigned long long) virt_to_phys(mpf) +
590 				sizeof(*mpf) - 1, mpf);
591 
592 			mem = virt_to_phys(mpf);
593 			memblock_reserve(mem, sizeof(*mpf));
594 			if (mpf->physptr)
595 				smp_reserve_memory(mpf);
596 
597 			return 1;
598 		}
599 		bp += 4;
600 		length -= 16;
601 	}
602 	return 0;
603 }
604 
605 void __init default_find_smp_config(void)
606 {
607 	unsigned int address;
608 
609 	/*
610 	 * FIXME: Linux assumes you have 640K of base ram..
611 	 * this continues the error...
612 	 *
613 	 * 1) Scan the bottom 1K for a signature
614 	 * 2) Scan the top 1K of base RAM
615 	 * 3) Scan the 64K of bios
616 	 */
617 	if (smp_scan_config(0x0, 0x400) ||
618 	    smp_scan_config(639 * 0x400, 0x400) ||
619 	    smp_scan_config(0xF0000, 0x10000))
620 		return;
621 	/*
622 	 * If it is an SMP machine we should know now, unless the
623 	 * configuration is in an EISA bus machine with an
624 	 * extended bios data area.
625 	 *
626 	 * there is a real-mode segmented pointer pointing to the
627 	 * 4K EBDA area at 0x40E, calculate and scan it here.
628 	 *
629 	 * NOTE! There are Linux loaders that will corrupt the EBDA
630 	 * area, and as such this kind of SMP config may be less
631 	 * trustworthy, simply because the SMP table may have been
632 	 * stomped on during early boot. These loaders are buggy and
633 	 * should be fixed.
634 	 *
635 	 * MP1.4 SPEC states to only scan first 1K of 4K EBDA.
636 	 */
637 
638 	address = get_bios_ebda();
639 	if (address)
640 		smp_scan_config(address, 0x400);
641 }
642 
643 #ifdef CONFIG_X86_IO_APIC
644 static u8 __initdata irq_used[MAX_IRQ_SOURCES];
645 
646 static int  __init get_MP_intsrc_index(struct mpc_intsrc *m)
647 {
648 	int i;
649 
650 	if (m->irqtype != mp_INT)
651 		return 0;
652 
653 	if (m->irqflag != 0x0f)
654 		return 0;
655 
656 	/* not legacy */
657 
658 	for (i = 0; i < mp_irq_entries; i++) {
659 		if (mp_irqs[i].irqtype != mp_INT)
660 			continue;
661 
662 		if (mp_irqs[i].irqflag != 0x0f)
663 			continue;
664 
665 		if (mp_irqs[i].srcbus != m->srcbus)
666 			continue;
667 		if (mp_irqs[i].srcbusirq != m->srcbusirq)
668 			continue;
669 		if (irq_used[i]) {
670 			/* already claimed */
671 			return -2;
672 		}
673 		irq_used[i] = 1;
674 		return i;
675 	}
676 
677 	/* not found */
678 	return -1;
679 }
680 
681 #define SPARE_SLOT_NUM 20
682 
683 static struct mpc_intsrc __initdata *m_spare[SPARE_SLOT_NUM];
684 
685 static void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare)
686 {
687 	int i;
688 
689 	apic_printk(APIC_VERBOSE, "OLD ");
690 	print_mp_irq_info(m);
691 
692 	i = get_MP_intsrc_index(m);
693 	if (i > 0) {
694 		memcpy(m, &mp_irqs[i], sizeof(*m));
695 		apic_printk(APIC_VERBOSE, "NEW ");
696 		print_mp_irq_info(&mp_irqs[i]);
697 		return;
698 	}
699 	if (!i) {
700 		/* legacy, do nothing */
701 		return;
702 	}
703 	if (*nr_m_spare < SPARE_SLOT_NUM) {
704 		/*
705 		 * not found (-1), or duplicated (-2) are invalid entries,
706 		 * we need to use the slot later
707 		 */
708 		m_spare[*nr_m_spare] = m;
709 		*nr_m_spare += 1;
710 	}
711 }
712 
713 static int __init
714 check_slot(unsigned long mpc_new_phys, unsigned long mpc_new_length, int count)
715 {
716 	if (!mpc_new_phys || count <= mpc_new_length) {
717 		WARN(1, "update_mptable: No spare slots (length: %x)\n", count);
718 		return -1;
719 	}
720 
721 	return 0;
722 }
723 #else /* CONFIG_X86_IO_APIC */
724 static
725 inline void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare) {}
726 #endif /* CONFIG_X86_IO_APIC */
727 
728 static int  __init replace_intsrc_all(struct mpc_table *mpc,
729 					unsigned long mpc_new_phys,
730 					unsigned long mpc_new_length)
731 {
732 #ifdef CONFIG_X86_IO_APIC
733 	int i;
734 #endif
735 	int count = sizeof(*mpc);
736 	int nr_m_spare = 0;
737 	unsigned char *mpt = ((unsigned char *)mpc) + count;
738 
739 	pr_info("mpc_length %x\n", mpc->length);
740 	while (count < mpc->length) {
741 		switch (*mpt) {
742 		case MP_PROCESSOR:
743 			skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
744 			break;
745 		case MP_BUS:
746 			skip_entry(&mpt, &count, sizeof(struct mpc_bus));
747 			break;
748 		case MP_IOAPIC:
749 			skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
750 			break;
751 		case MP_INTSRC:
752 			check_irq_src((struct mpc_intsrc *)mpt, &nr_m_spare);
753 			skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
754 			break;
755 		case MP_LINTSRC:
756 			skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
757 			break;
758 		default:
759 			/* wrong mptable */
760 			smp_dump_mptable(mpc, mpt);
761 			goto out;
762 		}
763 	}
764 
765 #ifdef CONFIG_X86_IO_APIC
766 	for (i = 0; i < mp_irq_entries; i++) {
767 		if (irq_used[i])
768 			continue;
769 
770 		if (mp_irqs[i].irqtype != mp_INT)
771 			continue;
772 
773 		if (mp_irqs[i].irqflag != 0x0f)
774 			continue;
775 
776 		if (nr_m_spare > 0) {
777 			apic_printk(APIC_VERBOSE, "*NEW* found\n");
778 			nr_m_spare--;
779 			memcpy(m_spare[nr_m_spare], &mp_irqs[i], sizeof(mp_irqs[i]));
780 			m_spare[nr_m_spare] = NULL;
781 		} else {
782 			struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
783 			count += sizeof(struct mpc_intsrc);
784 			if (check_slot(mpc_new_phys, mpc_new_length, count) < 0)
785 				goto out;
786 			memcpy(m, &mp_irqs[i], sizeof(*m));
787 			mpc->length = count;
788 			mpt += sizeof(struct mpc_intsrc);
789 		}
790 		print_mp_irq_info(&mp_irqs[i]);
791 	}
792 #endif
793 out:
794 	/* update checksum */
795 	mpc->checksum = 0;
796 	mpc->checksum -= mpf_checksum((unsigned char *)mpc, mpc->length);
797 
798 	return 0;
799 }
800 
801 int enable_update_mptable;
802 
803 static int __init update_mptable_setup(char *str)
804 {
805 	enable_update_mptable = 1;
806 #ifdef CONFIG_PCI
807 	pci_routeirq = 1;
808 #endif
809 	return 0;
810 }
811 early_param("update_mptable", update_mptable_setup);
812 
813 static unsigned long __initdata mpc_new_phys;
814 static unsigned long mpc_new_length __initdata = 4096;
815 
816 /* alloc_mptable or alloc_mptable=4k */
817 static int __initdata alloc_mptable;
818 static int __init parse_alloc_mptable_opt(char *p)
819 {
820 	enable_update_mptable = 1;
821 #ifdef CONFIG_PCI
822 	pci_routeirq = 1;
823 #endif
824 	alloc_mptable = 1;
825 	if (!p)
826 		return 0;
827 	mpc_new_length = memparse(p, &p);
828 	return 0;
829 }
830 early_param("alloc_mptable", parse_alloc_mptable_opt);
831 
832 void __init early_reserve_e820_mpc_new(void)
833 {
834 	if (enable_update_mptable && alloc_mptable)
835 		mpc_new_phys = early_reserve_e820(mpc_new_length, 4);
836 }
837 
838 static int __init update_mp_table(void)
839 {
840 	char str[16];
841 	char oem[10];
842 	struct mpf_intel *mpf;
843 	struct mpc_table *mpc, *mpc_new;
844 
845 	if (!enable_update_mptable)
846 		return 0;
847 
848 	mpf = mpf_found;
849 	if (!mpf)
850 		return 0;
851 
852 	/*
853 	 * Now see if we need to go further.
854 	 */
855 	if (mpf->feature1 != 0)
856 		return 0;
857 
858 	if (!mpf->physptr)
859 		return 0;
860 
861 	mpc = phys_to_virt(mpf->physptr);
862 
863 	if (!smp_check_mpc(mpc, oem, str))
864 		return 0;
865 
866 	pr_info("mpf: %llx\n", (u64)virt_to_phys(mpf));
867 	pr_info("physptr: %x\n", mpf->physptr);
868 
869 	if (mpc_new_phys && mpc->length > mpc_new_length) {
870 		mpc_new_phys = 0;
871 		pr_info("mpc_new_length is %ld, please use alloc_mptable=8k\n",
872 			mpc_new_length);
873 	}
874 
875 	if (!mpc_new_phys) {
876 		unsigned char old, new;
877 		/* check if we can change the position */
878 		mpc->checksum = 0;
879 		old = mpf_checksum((unsigned char *)mpc, mpc->length);
880 		mpc->checksum = 0xff;
881 		new = mpf_checksum((unsigned char *)mpc, mpc->length);
882 		if (old == new) {
883 			pr_info("mpc is readonly, please try alloc_mptable instead\n");
884 			return 0;
885 		}
886 		pr_info("use in-position replacing\n");
887 	} else {
888 		mpf->physptr = mpc_new_phys;
889 		mpc_new = phys_to_virt(mpc_new_phys);
890 		memcpy(mpc_new, mpc, mpc->length);
891 		mpc = mpc_new;
892 		/* check if we can modify that */
893 		if (mpc_new_phys - mpf->physptr) {
894 			struct mpf_intel *mpf_new;
895 			/* steal 16 bytes from [0, 1k) */
896 			pr_info("mpf new: %x\n", 0x400 - 16);
897 			mpf_new = phys_to_virt(0x400 - 16);
898 			memcpy(mpf_new, mpf, 16);
899 			mpf = mpf_new;
900 			mpf->physptr = mpc_new_phys;
901 		}
902 		mpf->checksum = 0;
903 		mpf->checksum -= mpf_checksum((unsigned char *)mpf, 16);
904 		pr_info("physptr new: %x\n", mpf->physptr);
905 	}
906 
907 	/*
908 	 * only replace the one with mp_INT and
909 	 *	 MP_IRQ_TRIGGER_LEVEL|MP_IRQ_POLARITY_LOW,
910 	 * already in mp_irqs , stored by ... and mp_config_acpi_gsi,
911 	 * may need pci=routeirq for all coverage
912 	 */
913 	replace_intsrc_all(mpc, mpc_new_phys, mpc_new_length);
914 
915 	return 0;
916 }
917 
918 late_initcall(update_mp_table);
919