xref: /openbmc/linux/arch/x86/kernel/cpu/amd.c (revision 90099433)
1 #include <linux/export.h>
2 #include <linux/init.h>
3 #include <linux/bitops.h>
4 #include <linux/elf.h>
5 #include <linux/mm.h>
6 
7 #include <linux/io.h>
8 #include <linux/sched.h>
9 #include <asm/processor.h>
10 #include <asm/apic.h>
11 #include <asm/cpu.h>
12 #include <asm/pci-direct.h>
13 
14 #ifdef CONFIG_X86_64
15 # include <asm/numa_64.h>
16 # include <asm/mmconfig.h>
17 # include <asm/cacheflush.h>
18 #endif
19 
20 #include "cpu.h"
21 
22 #ifdef CONFIG_X86_32
23 /*
24  *	B step AMD K6 before B 9730xxxx have hardware bugs that can cause
25  *	misexecution of code under Linux. Owners of such processors should
26  *	contact AMD for precise details and a CPU swap.
27  *
28  *	See	http://www.multimania.com/poulot/k6bug.html
29  *	and	section 2.6.2 of "AMD-K6 Processor Revision Guide - Model 6"
30  *		(Publication # 21266  Issue Date: August 1998)
31  *
32  *	The following test is erm.. interesting. AMD neglected to up
33  *	the chip setting when fixing the bug but they also tweaked some
34  *	performance at the same time..
35  */
36 
37 extern void vide(void);
38 __asm__(".align 4\nvide: ret");
39 
40 static void __cpuinit init_amd_k5(struct cpuinfo_x86 *c)
41 {
42 /*
43  * General Systems BIOSen alias the cpu frequency registers
44  * of the Elan at 0x000df000. Unfortuantly, one of the Linux
45  * drivers subsequently pokes it, and changes the CPU speed.
46  * Workaround : Remove the unneeded alias.
47  */
48 #define CBAR		(0xfffc) /* Configuration Base Address  (32-bit) */
49 #define CBAR_ENB	(0x80000000)
50 #define CBAR_KEY	(0X000000CB)
51 	if (c->x86_model == 9 || c->x86_model == 10) {
52 		if (inl(CBAR) & CBAR_ENB)
53 			outl(0 | CBAR_KEY, CBAR);
54 	}
55 }
56 
57 
58 static void __cpuinit init_amd_k6(struct cpuinfo_x86 *c)
59 {
60 	u32 l, h;
61 	int mbytes = num_physpages >> (20-PAGE_SHIFT);
62 
63 	if (c->x86_model < 6) {
64 		/* Based on AMD doc 20734R - June 2000 */
65 		if (c->x86_model == 0) {
66 			clear_cpu_cap(c, X86_FEATURE_APIC);
67 			set_cpu_cap(c, X86_FEATURE_PGE);
68 		}
69 		return;
70 	}
71 
72 	if (c->x86_model == 6 && c->x86_mask == 1) {
73 		const int K6_BUG_LOOP = 1000000;
74 		int n;
75 		void (*f_vide)(void);
76 		unsigned long d, d2;
77 
78 		printk(KERN_INFO "AMD K6 stepping B detected - ");
79 
80 		/*
81 		 * It looks like AMD fixed the 2.6.2 bug and improved indirect
82 		 * calls at the same time.
83 		 */
84 
85 		n = K6_BUG_LOOP;
86 		f_vide = vide;
87 		rdtscl(d);
88 		while (n--)
89 			f_vide();
90 		rdtscl(d2);
91 		d = d2-d;
92 
93 		if (d > 20*K6_BUG_LOOP)
94 			printk(KERN_CONT
95 				"system stability may be impaired when more than 32 MB are used.\n");
96 		else
97 			printk(KERN_CONT "probably OK (after B9730xxxx).\n");
98 	}
99 
100 	/* K6 with old style WHCR */
101 	if (c->x86_model < 8 ||
102 	   (c->x86_model == 8 && c->x86_mask < 8)) {
103 		/* We can only write allocate on the low 508Mb */
104 		if (mbytes > 508)
105 			mbytes = 508;
106 
107 		rdmsr(MSR_K6_WHCR, l, h);
108 		if ((l&0x0000FFFF) == 0) {
109 			unsigned long flags;
110 			l = (1<<0)|((mbytes/4)<<1);
111 			local_irq_save(flags);
112 			wbinvd();
113 			wrmsr(MSR_K6_WHCR, l, h);
114 			local_irq_restore(flags);
115 			printk(KERN_INFO "Enabling old style K6 write allocation for %d Mb\n",
116 				mbytes);
117 		}
118 		return;
119 	}
120 
121 	if ((c->x86_model == 8 && c->x86_mask > 7) ||
122 	     c->x86_model == 9 || c->x86_model == 13) {
123 		/* The more serious chips .. */
124 
125 		if (mbytes > 4092)
126 			mbytes = 4092;
127 
128 		rdmsr(MSR_K6_WHCR, l, h);
129 		if ((l&0xFFFF0000) == 0) {
130 			unsigned long flags;
131 			l = ((mbytes>>2)<<22)|(1<<16);
132 			local_irq_save(flags);
133 			wbinvd();
134 			wrmsr(MSR_K6_WHCR, l, h);
135 			local_irq_restore(flags);
136 			printk(KERN_INFO "Enabling new style K6 write allocation for %d Mb\n",
137 				mbytes);
138 		}
139 
140 		return;
141 	}
142 
143 	if (c->x86_model == 10) {
144 		/* AMD Geode LX is model 10 */
145 		/* placeholder for any needed mods */
146 		return;
147 	}
148 }
149 
150 static void __cpuinit amd_k7_smp_check(struct cpuinfo_x86 *c)
151 {
152 	/* calling is from identify_secondary_cpu() ? */
153 	if (!c->cpu_index)
154 		return;
155 
156 	/*
157 	 * Certain Athlons might work (for various values of 'work') in SMP
158 	 * but they are not certified as MP capable.
159 	 */
160 	/* Athlon 660/661 is valid. */
161 	if ((c->x86_model == 6) && ((c->x86_mask == 0) ||
162 	    (c->x86_mask == 1)))
163 		goto valid_k7;
164 
165 	/* Duron 670 is valid */
166 	if ((c->x86_model == 7) && (c->x86_mask == 0))
167 		goto valid_k7;
168 
169 	/*
170 	 * Athlon 662, Duron 671, and Athlon >model 7 have capability
171 	 * bit. It's worth noting that the A5 stepping (662) of some
172 	 * Athlon XP's have the MP bit set.
173 	 * See http://www.heise.de/newsticker/data/jow-18.10.01-000 for
174 	 * more.
175 	 */
176 	if (((c->x86_model == 6) && (c->x86_mask >= 2)) ||
177 	    ((c->x86_model == 7) && (c->x86_mask >= 1)) ||
178 	     (c->x86_model > 7))
179 		if (cpu_has_mp)
180 			goto valid_k7;
181 
182 	/* If we get here, not a certified SMP capable AMD system. */
183 
184 	/*
185 	 * Don't taint if we are running SMP kernel on a single non-MP
186 	 * approved Athlon
187 	 */
188 	WARN_ONCE(1, "WARNING: This combination of AMD"
189 		" processors is not suitable for SMP.\n");
190 	if (!test_taint(TAINT_UNSAFE_SMP))
191 		add_taint(TAINT_UNSAFE_SMP);
192 
193 valid_k7:
194 	;
195 }
196 
197 static void __cpuinit init_amd_k7(struct cpuinfo_x86 *c)
198 {
199 	u32 l, h;
200 
201 	/*
202 	 * Bit 15 of Athlon specific MSR 15, needs to be 0
203 	 * to enable SSE on Palomino/Morgan/Barton CPU's.
204 	 * If the BIOS didn't enable it already, enable it here.
205 	 */
206 	if (c->x86_model >= 6 && c->x86_model <= 10) {
207 		if (!cpu_has(c, X86_FEATURE_XMM)) {
208 			printk(KERN_INFO "Enabling disabled K7/SSE Support.\n");
209 			rdmsr(MSR_K7_HWCR, l, h);
210 			l &= ~0x00008000;
211 			wrmsr(MSR_K7_HWCR, l, h);
212 			set_cpu_cap(c, X86_FEATURE_XMM);
213 		}
214 	}
215 
216 	/*
217 	 * It's been determined by AMD that Athlons since model 8 stepping 1
218 	 * are more robust with CLK_CTL set to 200xxxxx instead of 600xxxxx
219 	 * As per AMD technical note 27212 0.2
220 	 */
221 	if ((c->x86_model == 8 && c->x86_mask >= 1) || (c->x86_model > 8)) {
222 		rdmsr(MSR_K7_CLK_CTL, l, h);
223 		if ((l & 0xfff00000) != 0x20000000) {
224 			printk(KERN_INFO
225 			    "CPU: CLK_CTL MSR was %x. Reprogramming to %x\n",
226 					l, ((l & 0x000fffff)|0x20000000));
227 			wrmsr(MSR_K7_CLK_CTL, (l & 0x000fffff)|0x20000000, h);
228 		}
229 	}
230 
231 	set_cpu_cap(c, X86_FEATURE_K7);
232 
233 	amd_k7_smp_check(c);
234 }
235 #endif
236 
237 #ifdef CONFIG_NUMA
238 /*
239  * To workaround broken NUMA config.  Read the comment in
240  * srat_detect_node().
241  */
242 static int __cpuinit nearby_node(int apicid)
243 {
244 	int i, node;
245 
246 	for (i = apicid - 1; i >= 0; i--) {
247 		node = __apicid_to_node[i];
248 		if (node != NUMA_NO_NODE && node_online(node))
249 			return node;
250 	}
251 	for (i = apicid + 1; i < MAX_LOCAL_APIC; i++) {
252 		node = __apicid_to_node[i];
253 		if (node != NUMA_NO_NODE && node_online(node))
254 			return node;
255 	}
256 	return first_node(node_online_map); /* Shouldn't happen */
257 }
258 #endif
259 
260 /*
261  * Fixup core topology information for
262  * (1) AMD multi-node processors
263  *     Assumption: Number of cores in each internal node is the same.
264  * (2) AMD processors supporting compute units
265  */
266 #ifdef CONFIG_X86_HT
267 static void __cpuinit amd_get_topology(struct cpuinfo_x86 *c)
268 {
269 	u32 nodes, cores_per_cu = 1;
270 	u8 node_id;
271 	int cpu = smp_processor_id();
272 
273 	/* get information required for multi-node processors */
274 	if (cpu_has(c, X86_FEATURE_TOPOEXT)) {
275 		u32 eax, ebx, ecx, edx;
276 
277 		cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
278 		nodes = ((ecx >> 8) & 7) + 1;
279 		node_id = ecx & 7;
280 
281 		/* get compute unit information */
282 		smp_num_siblings = ((ebx >> 8) & 3) + 1;
283 		c->compute_unit_id = ebx & 0xff;
284 		cores_per_cu += ((ebx >> 8) & 3);
285 	} else if (cpu_has(c, X86_FEATURE_NODEID_MSR)) {
286 		u64 value;
287 
288 		rdmsrl(MSR_FAM10H_NODE_ID, value);
289 		nodes = ((value >> 3) & 7) + 1;
290 		node_id = value & 7;
291 	} else
292 		return;
293 
294 	/* fixup multi-node processor information */
295 	if (nodes > 1) {
296 		u32 cores_per_node;
297 		u32 cus_per_node;
298 
299 		set_cpu_cap(c, X86_FEATURE_AMD_DCM);
300 		cores_per_node = c->x86_max_cores / nodes;
301 		cus_per_node = cores_per_node / cores_per_cu;
302 
303 		/* store NodeID, use llc_shared_map to store sibling info */
304 		per_cpu(cpu_llc_id, cpu) = node_id;
305 
306 		/* core id has to be in the [0 .. cores_per_node - 1] range */
307 		c->cpu_core_id %= cores_per_node;
308 		c->compute_unit_id %= cus_per_node;
309 	}
310 }
311 #endif
312 
313 /*
314  * On a AMD dual core setup the lower bits of the APIC id distingush the cores.
315  * Assumes number of cores is a power of two.
316  */
317 static void __cpuinit amd_detect_cmp(struct cpuinfo_x86 *c)
318 {
319 #ifdef CONFIG_X86_HT
320 	unsigned bits;
321 	int cpu = smp_processor_id();
322 
323 	bits = c->x86_coreid_bits;
324 	/* Low order bits define the core id (index of core in socket) */
325 	c->cpu_core_id = c->initial_apicid & ((1 << bits)-1);
326 	/* Convert the initial APIC ID into the socket ID */
327 	c->phys_proc_id = c->initial_apicid >> bits;
328 	/* use socket ID also for last level cache */
329 	per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
330 	amd_get_topology(c);
331 #endif
332 }
333 
334 int amd_get_nb_id(int cpu)
335 {
336 	int id = 0;
337 #ifdef CONFIG_SMP
338 	id = per_cpu(cpu_llc_id, cpu);
339 #endif
340 	return id;
341 }
342 EXPORT_SYMBOL_GPL(amd_get_nb_id);
343 
344 static void __cpuinit srat_detect_node(struct cpuinfo_x86 *c)
345 {
346 #ifdef CONFIG_NUMA
347 	int cpu = smp_processor_id();
348 	int node;
349 	unsigned apicid = c->apicid;
350 
351 	node = numa_cpu_node(cpu);
352 	if (node == NUMA_NO_NODE)
353 		node = per_cpu(cpu_llc_id, cpu);
354 
355 	/*
356 	 * On multi-fabric platform (e.g. Numascale NumaChip) a
357 	 * platform-specific handler needs to be called to fixup some
358 	 * IDs of the CPU.
359 	 */
360 	if (x86_cpuinit.fixup_cpu_id)
361 		x86_cpuinit.fixup_cpu_id(c, node);
362 
363 	if (!node_online(node)) {
364 		/*
365 		 * Two possibilities here:
366 		 *
367 		 * - The CPU is missing memory and no node was created.  In
368 		 *   that case try picking one from a nearby CPU.
369 		 *
370 		 * - The APIC IDs differ from the HyperTransport node IDs
371 		 *   which the K8 northbridge parsing fills in.  Assume
372 		 *   they are all increased by a constant offset, but in
373 		 *   the same order as the HT nodeids.  If that doesn't
374 		 *   result in a usable node fall back to the path for the
375 		 *   previous case.
376 		 *
377 		 * This workaround operates directly on the mapping between
378 		 * APIC ID and NUMA node, assuming certain relationship
379 		 * between APIC ID, HT node ID and NUMA topology.  As going
380 		 * through CPU mapping may alter the outcome, directly
381 		 * access __apicid_to_node[].
382 		 */
383 		int ht_nodeid = c->initial_apicid;
384 
385 		if (ht_nodeid >= 0 &&
386 		    __apicid_to_node[ht_nodeid] != NUMA_NO_NODE)
387 			node = __apicid_to_node[ht_nodeid];
388 		/* Pick a nearby node */
389 		if (!node_online(node))
390 			node = nearby_node(apicid);
391 	}
392 	numa_set_node(cpu, node);
393 #endif
394 }
395 
396 static void __cpuinit early_init_amd_mc(struct cpuinfo_x86 *c)
397 {
398 #ifdef CONFIG_X86_HT
399 	unsigned bits, ecx;
400 
401 	/* Multi core CPU? */
402 	if (c->extended_cpuid_level < 0x80000008)
403 		return;
404 
405 	ecx = cpuid_ecx(0x80000008);
406 
407 	c->x86_max_cores = (ecx & 0xff) + 1;
408 
409 	/* CPU telling us the core id bits shift? */
410 	bits = (ecx >> 12) & 0xF;
411 
412 	/* Otherwise recompute */
413 	if (bits == 0) {
414 		while ((1 << bits) < c->x86_max_cores)
415 			bits++;
416 	}
417 
418 	c->x86_coreid_bits = bits;
419 #endif
420 }
421 
422 static void __cpuinit bsp_init_amd(struct cpuinfo_x86 *c)
423 {
424 	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
425 
426 		if (c->x86 > 0x10 ||
427 		    (c->x86 == 0x10 && c->x86_model >= 0x2)) {
428 			u64 val;
429 
430 			rdmsrl(MSR_K7_HWCR, val);
431 			if (!(val & BIT(24)))
432 				printk(KERN_WARNING FW_BUG "TSC doesn't count "
433 					"with P0 frequency!\n");
434 		}
435 	}
436 
437 	if (c->x86 == 0x15) {
438 		unsigned long upperbit;
439 		u32 cpuid, assoc;
440 
441 		cpuid	 = cpuid_edx(0x80000005);
442 		assoc	 = cpuid >> 16 & 0xff;
443 		upperbit = ((cpuid >> 24) << 10) / assoc;
444 
445 		va_align.mask	  = (upperbit - 1) & PAGE_MASK;
446 		va_align.flags    = ALIGN_VA_32 | ALIGN_VA_64;
447 	}
448 }
449 
450 static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
451 {
452 	early_init_amd_mc(c);
453 
454 	/*
455 	 * c->x86_power is 8000_0007 edx. Bit 8 is TSC runs at constant rate
456 	 * with P/T states and does not stop in deep C-states
457 	 */
458 	if (c->x86_power & (1 << 8)) {
459 		set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
460 		set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
461 		if (!check_tsc_unstable())
462 			sched_clock_stable = 1;
463 	}
464 
465 #ifdef CONFIG_X86_64
466 	set_cpu_cap(c, X86_FEATURE_SYSCALL32);
467 #else
468 	/*  Set MTRR capability flag if appropriate */
469 	if (c->x86 == 5)
470 		if (c->x86_model == 13 || c->x86_model == 9 ||
471 		    (c->x86_model == 8 && c->x86_mask >= 8))
472 			set_cpu_cap(c, X86_FEATURE_K6_MTRR);
473 #endif
474 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PCI)
475 	/* check CPU config space for extended APIC ID */
476 	if (cpu_has_apic && c->x86 >= 0xf) {
477 		unsigned int val;
478 		val = read_pci_config(0, 24, 0, 0x68);
479 		if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18)))
480 			set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
481 	}
482 #endif
483 }
484 
485 static void __cpuinit init_amd(struct cpuinfo_x86 *c)
486 {
487 	u32 dummy;
488 
489 #ifdef CONFIG_SMP
490 	unsigned long long value;
491 
492 	/*
493 	 * Disable TLB flush filter by setting HWCR.FFDIS on K8
494 	 * bit 6 of msr C001_0015
495 	 *
496 	 * Errata 63 for SH-B3 steppings
497 	 * Errata 122 for all steppings (F+ have it disabled by default)
498 	 */
499 	if (c->x86 == 0xf) {
500 		rdmsrl(MSR_K7_HWCR, value);
501 		value |= 1 << 6;
502 		wrmsrl(MSR_K7_HWCR, value);
503 	}
504 #endif
505 
506 	early_init_amd(c);
507 
508 	/*
509 	 * Bit 31 in normal CPUID used for nonstandard 3DNow ID;
510 	 * 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway
511 	 */
512 	clear_cpu_cap(c, 0*32+31);
513 
514 #ifdef CONFIG_X86_64
515 	/* On C+ stepping K8 rep microcode works well for copy/memset */
516 	if (c->x86 == 0xf) {
517 		u32 level;
518 
519 		level = cpuid_eax(1);
520 		if ((level >= 0x0f48 && level < 0x0f50) || level >= 0x0f58)
521 			set_cpu_cap(c, X86_FEATURE_REP_GOOD);
522 
523 		/*
524 		 * Some BIOSes incorrectly force this feature, but only K8
525 		 * revision D (model = 0x14) and later actually support it.
526 		 * (AMD Erratum #110, docId: 25759).
527 		 */
528 		if (c->x86_model < 0x14 && cpu_has(c, X86_FEATURE_LAHF_LM)) {
529 			u64 val;
530 
531 			clear_cpu_cap(c, X86_FEATURE_LAHF_LM);
532 			if (!rdmsrl_amd_safe(0xc001100d, &val)) {
533 				val &= ~(1ULL << 32);
534 				wrmsrl_amd_safe(0xc001100d, val);
535 			}
536 		}
537 
538 	}
539 	if (c->x86 >= 0x10)
540 		set_cpu_cap(c, X86_FEATURE_REP_GOOD);
541 
542 	/* get apicid instead of initial apic id from cpuid */
543 	c->apicid = hard_smp_processor_id();
544 #else
545 
546 	/*
547 	 *	FIXME: We should handle the K5 here. Set up the write
548 	 *	range and also turn on MSR 83 bits 4 and 31 (write alloc,
549 	 *	no bus pipeline)
550 	 */
551 
552 	switch (c->x86) {
553 	case 4:
554 		init_amd_k5(c);
555 		break;
556 	case 5:
557 		init_amd_k6(c);
558 		break;
559 	case 6: /* An Athlon/Duron */
560 		init_amd_k7(c);
561 		break;
562 	}
563 
564 	/* K6s reports MCEs but don't actually have all the MSRs */
565 	if (c->x86 < 6)
566 		clear_cpu_cap(c, X86_FEATURE_MCE);
567 #endif
568 
569 	/* Enable workaround for FXSAVE leak */
570 	if (c->x86 >= 6)
571 		set_cpu_cap(c, X86_FEATURE_FXSAVE_LEAK);
572 
573 	if (!c->x86_model_id[0]) {
574 		switch (c->x86) {
575 		case 0xf:
576 			/* Should distinguish Models here, but this is only
577 			   a fallback anyways. */
578 			strcpy(c->x86_model_id, "Hammer");
579 			break;
580 		}
581 	}
582 
583 	cpu_detect_cache_sizes(c);
584 
585 	/* Multi core CPU? */
586 	if (c->extended_cpuid_level >= 0x80000008) {
587 		amd_detect_cmp(c);
588 		srat_detect_node(c);
589 	}
590 
591 #ifdef CONFIG_X86_32
592 	detect_ht(c);
593 #endif
594 
595 	if (c->extended_cpuid_level >= 0x80000006) {
596 		if (cpuid_edx(0x80000006) & 0xf000)
597 			num_cache_leaves = 4;
598 		else
599 			num_cache_leaves = 3;
600 	}
601 
602 	if (c->x86 >= 0xf)
603 		set_cpu_cap(c, X86_FEATURE_K8);
604 
605 	if (cpu_has_xmm2) {
606 		/* MFENCE stops RDTSC speculation */
607 		set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
608 	}
609 
610 #ifdef CONFIG_X86_64
611 	if (c->x86 == 0x10) {
612 		/* do this for boot cpu */
613 		if (c == &boot_cpu_data)
614 			check_enable_amd_mmconf_dmi();
615 
616 		fam10h_check_enable_mmcfg();
617 	}
618 
619 	if (c == &boot_cpu_data && c->x86 >= 0xf) {
620 		unsigned long long tseg;
621 
622 		/*
623 		 * Split up direct mapping around the TSEG SMM area.
624 		 * Don't do it for gbpages because there seems very little
625 		 * benefit in doing so.
626 		 */
627 		if (!rdmsrl_safe(MSR_K8_TSEG_ADDR, &tseg)) {
628 			printk(KERN_DEBUG "tseg: %010llx\n", tseg);
629 			if ((tseg>>PMD_SHIFT) <
630 				(max_low_pfn_mapped>>(PMD_SHIFT-PAGE_SHIFT)) ||
631 				((tseg>>PMD_SHIFT) <
632 				(max_pfn_mapped>>(PMD_SHIFT-PAGE_SHIFT)) &&
633 				(tseg>>PMD_SHIFT) >= (1ULL<<(32 - PMD_SHIFT))))
634 				set_memory_4k((unsigned long)__va(tseg), 1);
635 		}
636 	}
637 #endif
638 
639 	/*
640 	 * Family 0x12 and above processors have APIC timer
641 	 * running in deep C states.
642 	 */
643 	if (c->x86 > 0x11)
644 		set_cpu_cap(c, X86_FEATURE_ARAT);
645 
646 	/*
647 	 * Disable GART TLB Walk Errors on Fam10h. We do this here
648 	 * because this is always needed when GART is enabled, even in a
649 	 * kernel which has no MCE support built in.
650 	 */
651 	if (c->x86 == 0x10) {
652 		/*
653 		 * BIOS should disable GartTlbWlk Errors themself. If
654 		 * it doesn't do it here as suggested by the BKDG.
655 		 *
656 		 * Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=33012
657 		 */
658 		u64 mask;
659 		int err;
660 
661 		err = rdmsrl_safe(MSR_AMD64_MCx_MASK(4), &mask);
662 		if (err == 0) {
663 			mask |= (1 << 10);
664 			checking_wrmsrl(MSR_AMD64_MCx_MASK(4), mask);
665 		}
666 	}
667 
668 	rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);
669 }
670 
671 #ifdef CONFIG_X86_32
672 static unsigned int __cpuinit amd_size_cache(struct cpuinfo_x86 *c,
673 							unsigned int size)
674 {
675 	/* AMD errata T13 (order #21922) */
676 	if ((c->x86 == 6)) {
677 		/* Duron Rev A0 */
678 		if (c->x86_model == 3 && c->x86_mask == 0)
679 			size = 64;
680 		/* Tbird rev A1/A2 */
681 		if (c->x86_model == 4 &&
682 			(c->x86_mask == 0 || c->x86_mask == 1))
683 			size = 256;
684 	}
685 	return size;
686 }
687 #endif
688 
689 static const struct cpu_dev __cpuinitconst amd_cpu_dev = {
690 	.c_vendor	= "AMD",
691 	.c_ident	= { "AuthenticAMD" },
692 #ifdef CONFIG_X86_32
693 	.c_models = {
694 		{ .vendor = X86_VENDOR_AMD, .family = 4, .model_names =
695 		  {
696 			  [3] = "486 DX/2",
697 			  [7] = "486 DX/2-WB",
698 			  [8] = "486 DX/4",
699 			  [9] = "486 DX/4-WB",
700 			  [14] = "Am5x86-WT",
701 			  [15] = "Am5x86-WB"
702 		  }
703 		},
704 	},
705 	.c_size_cache	= amd_size_cache,
706 #endif
707 	.c_early_init   = early_init_amd,
708 	.c_bsp_init	= bsp_init_amd,
709 	.c_init		= init_amd,
710 	.c_x86_vendor	= X86_VENDOR_AMD,
711 };
712 
713 cpu_dev_register(amd_cpu_dev);
714 
715 /*
716  * AMD errata checking
717  *
718  * Errata are defined as arrays of ints using the AMD_LEGACY_ERRATUM() or
719  * AMD_OSVW_ERRATUM() macros. The latter is intended for newer errata that
720  * have an OSVW id assigned, which it takes as first argument. Both take a
721  * variable number of family-specific model-stepping ranges created by
722  * AMD_MODEL_RANGE(). Each erratum also has to be declared as extern const
723  * int[] in arch/x86/include/asm/processor.h.
724  *
725  * Example:
726  *
727  * const int amd_erratum_319[] =
728  *	AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x10, 0x2, 0x1, 0x4, 0x2),
729  *			   AMD_MODEL_RANGE(0x10, 0x8, 0x0, 0x8, 0x0),
730  *			   AMD_MODEL_RANGE(0x10, 0x9, 0x0, 0x9, 0x0));
731  */
732 
733 const int amd_erratum_400[] =
734 	AMD_OSVW_ERRATUM(1, AMD_MODEL_RANGE(0xf, 0x41, 0x2, 0xff, 0xf),
735 			    AMD_MODEL_RANGE(0x10, 0x2, 0x1, 0xff, 0xf));
736 EXPORT_SYMBOL_GPL(amd_erratum_400);
737 
738 const int amd_erratum_383[] =
739 	AMD_OSVW_ERRATUM(3, AMD_MODEL_RANGE(0x10, 0, 0, 0xff, 0xf));
740 EXPORT_SYMBOL_GPL(amd_erratum_383);
741 
742 bool cpu_has_amd_erratum(const int *erratum)
743 {
744 	struct cpuinfo_x86 *cpu = __this_cpu_ptr(&cpu_info);
745 	int osvw_id = *erratum++;
746 	u32 range;
747 	u32 ms;
748 
749 	/*
750 	 * If called early enough that current_cpu_data hasn't been initialized
751 	 * yet, fall back to boot_cpu_data.
752 	 */
753 	if (cpu->x86 == 0)
754 		cpu = &boot_cpu_data;
755 
756 	if (cpu->x86_vendor != X86_VENDOR_AMD)
757 		return false;
758 
759 	if (osvw_id >= 0 && osvw_id < 65536 &&
760 	    cpu_has(cpu, X86_FEATURE_OSVW)) {
761 		u64 osvw_len;
762 
763 		rdmsrl(MSR_AMD64_OSVW_ID_LENGTH, osvw_len);
764 		if (osvw_id < osvw_len) {
765 			u64 osvw_bits;
766 
767 			rdmsrl(MSR_AMD64_OSVW_STATUS + (osvw_id >> 6),
768 			    osvw_bits);
769 			return osvw_bits & (1ULL << (osvw_id & 0x3f));
770 		}
771 	}
772 
773 	/* OSVW unavailable or ID unknown, match family-model-stepping range */
774 	ms = (cpu->x86_model << 4) | cpu->x86_mask;
775 	while ((range = *erratum++))
776 		if ((cpu->x86 == AMD_MODEL_RANGE_FAMILY(range)) &&
777 		    (ms >= AMD_MODEL_RANGE_START(range)) &&
778 		    (ms <= AMD_MODEL_RANGE_END(range)))
779 			return true;
780 
781 	return false;
782 }
783 
784 EXPORT_SYMBOL_GPL(cpu_has_amd_erratum);
785