xref: /openbmc/linux/arch/powerpc/kernel/setup_64.c (revision 0883c2c0)
1 /*
2  *
3  * Common boot and setup code.
4  *
5  * Copyright (C) 2001 PPC64 Team, IBM Corp
6  *
7  *      This program is free software; you can redistribute it and/or
8  *      modify it under the terms of the GNU General Public License
9  *      as published by the Free Software Foundation; either version
10  *      2 of the License, or (at your option) any later version.
11  */
12 
13 #define DEBUG
14 
15 #include <linux/export.h>
16 #include <linux/string.h>
17 #include <linux/sched.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/reboot.h>
21 #include <linux/delay.h>
22 #include <linux/initrd.h>
23 #include <linux/seq_file.h>
24 #include <linux/ioport.h>
25 #include <linux/console.h>
26 #include <linux/utsname.h>
27 #include <linux/tty.h>
28 #include <linux/root_dev.h>
29 #include <linux/notifier.h>
30 #include <linux/cpu.h>
31 #include <linux/unistd.h>
32 #include <linux/serial.h>
33 #include <linux/serial_8250.h>
34 #include <linux/bootmem.h>
35 #include <linux/pci.h>
36 #include <linux/lockdep.h>
37 #include <linux/memblock.h>
38 #include <linux/hugetlb.h>
39 #include <linux/memory.h>
40 #include <linux/nmi.h>
41 
42 #include <asm/io.h>
43 #include <asm/kdump.h>
44 #include <asm/prom.h>
45 #include <asm/processor.h>
46 #include <asm/pgtable.h>
47 #include <asm/smp.h>
48 #include <asm/elf.h>
49 #include <asm/machdep.h>
50 #include <asm/paca.h>
51 #include <asm/time.h>
52 #include <asm/cputable.h>
53 #include <asm/sections.h>
54 #include <asm/btext.h>
55 #include <asm/nvram.h>
56 #include <asm/setup.h>
57 #include <asm/rtas.h>
58 #include <asm/iommu.h>
59 #include <asm/serial.h>
60 #include <asm/cache.h>
61 #include <asm/page.h>
62 #include <asm/mmu.h>
63 #include <asm/firmware.h>
64 #include <asm/xmon.h>
65 #include <asm/udbg.h>
66 #include <asm/kexec.h>
67 #include <asm/mmu_context.h>
68 #include <asm/code-patching.h>
69 #include <asm/kvm_ppc.h>
70 #include <asm/hugetlb.h>
71 #include <asm/epapr_hcalls.h>
72 #include <asm/livepatch.h>
73 
74 #ifdef DEBUG
75 #define DBG(fmt...) udbg_printf(fmt)
76 #else
77 #define DBG(fmt...)
78 #endif
79 
80 int spinning_secondaries;
81 u64 ppc64_pft_size;
82 
83 /* Pick defaults since we might want to patch instructions
84  * before we've read this from the device tree.
85  */
86 struct ppc64_caches ppc64_caches = {
87 	.dline_size = 0x40,
88 	.log_dline_size = 6,
89 	.iline_size = 0x40,
90 	.log_iline_size = 6
91 };
92 EXPORT_SYMBOL_GPL(ppc64_caches);
93 
94 /*
95  * These are used in binfmt_elf.c to put aux entries on the stack
96  * for each elf executable being started.
97  */
98 int dcache_bsize;
99 int icache_bsize;
100 int ucache_bsize;
101 
102 #if defined(CONFIG_PPC_BOOK3E) && defined(CONFIG_SMP)
103 static void setup_tlb_core_data(void)
104 {
105 	int cpu;
106 
107 	BUILD_BUG_ON(offsetof(struct tlb_core_data, lock) != 0);
108 
109 	for_each_possible_cpu(cpu) {
110 		int first = cpu_first_thread_sibling(cpu);
111 
112 		/*
113 		 * If we boot via kdump on a non-primary thread,
114 		 * make sure we point at the thread that actually
115 		 * set up this TLB.
116 		 */
117 		if (cpu_first_thread_sibling(boot_cpuid) == first)
118 			first = boot_cpuid;
119 
120 		paca[cpu].tcd_ptr = &paca[first].tcd;
121 
122 		/*
123 		 * If we have threads, we need either tlbsrx.
124 		 * or e6500 tablewalk mode, or else TLB handlers
125 		 * will be racy and could produce duplicate entries.
126 		 */
127 		if (smt_enabled_at_boot >= 2 &&
128 		    !mmu_has_feature(MMU_FTR_USE_TLBRSRV) &&
129 		    book3e_htw_mode != PPC_HTW_E6500) {
130 			/* Should we panic instead? */
131 			WARN_ONCE("%s: unsupported MMU configuration -- expect problems\n",
132 				  __func__);
133 		}
134 	}
135 }
136 #else
137 static void setup_tlb_core_data(void)
138 {
139 }
140 #endif
141 
142 #ifdef CONFIG_SMP
143 
144 static char *smt_enabled_cmdline;
145 
146 /* Look for ibm,smt-enabled OF option */
147 static void check_smt_enabled(void)
148 {
149 	struct device_node *dn;
150 	const char *smt_option;
151 
152 	/* Default to enabling all threads */
153 	smt_enabled_at_boot = threads_per_core;
154 
155 	/* Allow the command line to overrule the OF option */
156 	if (smt_enabled_cmdline) {
157 		if (!strcmp(smt_enabled_cmdline, "on"))
158 			smt_enabled_at_boot = threads_per_core;
159 		else if (!strcmp(smt_enabled_cmdline, "off"))
160 			smt_enabled_at_boot = 0;
161 		else {
162 			int smt;
163 			int rc;
164 
165 			rc = kstrtoint(smt_enabled_cmdline, 10, &smt);
166 			if (!rc)
167 				smt_enabled_at_boot =
168 					min(threads_per_core, smt);
169 		}
170 	} else {
171 		dn = of_find_node_by_path("/options");
172 		if (dn) {
173 			smt_option = of_get_property(dn, "ibm,smt-enabled",
174 						     NULL);
175 
176 			if (smt_option) {
177 				if (!strcmp(smt_option, "on"))
178 					smt_enabled_at_boot = threads_per_core;
179 				else if (!strcmp(smt_option, "off"))
180 					smt_enabled_at_boot = 0;
181 			}
182 
183 			of_node_put(dn);
184 		}
185 	}
186 }
187 
188 /* Look for smt-enabled= cmdline option */
189 static int __init early_smt_enabled(char *p)
190 {
191 	smt_enabled_cmdline = p;
192 	return 0;
193 }
194 early_param("smt-enabled", early_smt_enabled);
195 
196 #else
197 #define check_smt_enabled()
198 #endif /* CONFIG_SMP */
199 
200 /** Fix up paca fields required for the boot cpu */
201 static void fixup_boot_paca(void)
202 {
203 	/* The boot cpu is started */
204 	get_paca()->cpu_start = 1;
205 	/* Allow percpu accesses to work until we setup percpu data */
206 	get_paca()->data_offset = 0;
207 }
208 
209 static void cpu_ready_for_interrupts(void)
210 {
211 	/* Set IR and DR in PACA MSR */
212 	get_paca()->kernel_msr = MSR_KERNEL;
213 
214 	/*
215 	 * Enable AIL if supported, and we are in hypervisor mode. If we are
216 	 * not in hypervisor mode, we enable relocation-on interrupts later
217 	 * in pSeries_setup_arch() using the H_SET_MODE hcall.
218 	 */
219 	if (cpu_has_feature(CPU_FTR_HVMODE) &&
220 	    cpu_has_feature(CPU_FTR_ARCH_207S)) {
221 		unsigned long lpcr = mfspr(SPRN_LPCR);
222 		mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
223 	}
224 }
225 
226 /*
227  * Early initialization entry point. This is called by head.S
228  * with MMU translation disabled. We rely on the "feature" of
229  * the CPU that ignores the top 2 bits of the address in real
230  * mode so we can access kernel globals normally provided we
231  * only toy with things in the RMO region. From here, we do
232  * some early parsing of the device-tree to setup out MEMBLOCK
233  * data structures, and allocate & initialize the hash table
234  * and segment tables so we can start running with translation
235  * enabled.
236  *
237  * It is this function which will call the probe() callback of
238  * the various platform types and copy the matching one to the
239  * global ppc_md structure. Your platform can eventually do
240  * some very early initializations from the probe() routine, but
241  * this is not recommended, be very careful as, for example, the
242  * device-tree is not accessible via normal means at this point.
243  */
244 
245 void __init early_setup(unsigned long dt_ptr)
246 {
247 	static __initdata struct paca_struct boot_paca;
248 
249 	/* -------- printk is _NOT_ safe to use here ! ------- */
250 
251 	/* Identify CPU type */
252 	identify_cpu(0, mfspr(SPRN_PVR));
253 
254 	/* Assume we're on cpu 0 for now. Don't write to the paca yet! */
255 	initialise_paca(&boot_paca, 0);
256 	setup_paca(&boot_paca);
257 	fixup_boot_paca();
258 
259 	/* -------- printk is now safe to use ------- */
260 
261 	/* Enable early debugging if any specified (see udbg.h) */
262 	udbg_early_init();
263 
264  	DBG(" -> early_setup(), dt_ptr: 0x%lx\n", dt_ptr);
265 
266 	/*
267 	 * Do early initialization using the flattened device
268 	 * tree, such as retrieving the physical memory map or
269 	 * calculating/retrieving the hash table size.
270 	 */
271 	early_init_devtree(__va(dt_ptr));
272 
273 	epapr_paravirt_early_init();
274 
275 	/* Now we know the logical id of our boot cpu, setup the paca. */
276 	setup_paca(&paca[boot_cpuid]);
277 	fixup_boot_paca();
278 
279 	/* Probe the machine type */
280 	probe_machine();
281 
282 	setup_kdump_trampoline();
283 
284 	DBG("Found, Initializing memory management...\n");
285 
286 	/* Initialize the hash table or TLB handling */
287 	early_init_mmu();
288 
289 	/*
290 	 * At this point, we can let interrupts switch to virtual mode
291 	 * (the MMU has been setup), so adjust the MSR in the PACA to
292 	 * have IR and DR set and enable AIL if it exists
293 	 */
294 	cpu_ready_for_interrupts();
295 
296 	/* Reserve large chunks of memory for use by CMA for KVM */
297 	kvm_cma_reserve();
298 
299 	/*
300 	 * Reserve any gigantic pages requested on the command line.
301 	 * memblock needs to have been initialized by the time this is
302 	 * called since this will reserve memory.
303 	 */
304 	reserve_hugetlb_gpages();
305 
306 	DBG(" <- early_setup()\n");
307 
308 #ifdef CONFIG_PPC_EARLY_DEBUG_BOOTX
309 	/*
310 	 * This needs to be done *last* (after the above DBG() even)
311 	 *
312 	 * Right after we return from this function, we turn on the MMU
313 	 * which means the real-mode access trick that btext does will
314 	 * no longer work, it needs to switch to using a real MMU
315 	 * mapping. This call will ensure that it does
316 	 */
317 	btext_map();
318 #endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */
319 }
320 
321 #ifdef CONFIG_SMP
322 void early_setup_secondary(void)
323 {
324 	/* Mark interrupts disabled in PACA */
325 	get_paca()->soft_enabled = 0;
326 
327 	/* Initialize the hash table or TLB handling */
328 	early_init_mmu_secondary();
329 
330 	/*
331 	 * At this point, we can let interrupts switch to virtual mode
332 	 * (the MMU has been setup), so adjust the MSR in the PACA to
333 	 * have IR and DR set.
334 	 */
335 	cpu_ready_for_interrupts();
336 }
337 
338 #endif /* CONFIG_SMP */
339 
340 #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
341 static bool use_spinloop(void)
342 {
343 	if (!IS_ENABLED(CONFIG_PPC_BOOK3E))
344 		return true;
345 
346 	/*
347 	 * When book3e boots from kexec, the ePAPR spin table does
348 	 * not get used.
349 	 */
350 	return of_property_read_bool(of_chosen, "linux,booted-from-kexec");
351 }
352 
353 void smp_release_cpus(void)
354 {
355 	unsigned long *ptr;
356 	int i;
357 
358 	if (!use_spinloop())
359 		return;
360 
361 	DBG(" -> smp_release_cpus()\n");
362 
363 	/* All secondary cpus are spinning on a common spinloop, release them
364 	 * all now so they can start to spin on their individual paca
365 	 * spinloops. For non SMP kernels, the secondary cpus never get out
366 	 * of the common spinloop.
367 	 */
368 
369 	ptr  = (unsigned long *)((unsigned long)&__secondary_hold_spinloop
370 			- PHYSICAL_START);
371 	*ptr = ppc_function_entry(generic_secondary_smp_init);
372 
373 	/* And wait a bit for them to catch up */
374 	for (i = 0; i < 100000; i++) {
375 		mb();
376 		HMT_low();
377 		if (spinning_secondaries == 0)
378 			break;
379 		udelay(1);
380 	}
381 	DBG("spinning_secondaries = %d\n", spinning_secondaries);
382 
383 	DBG(" <- smp_release_cpus()\n");
384 }
385 #endif /* CONFIG_SMP || CONFIG_KEXEC */
386 
387 /*
388  * Initialize some remaining members of the ppc64_caches and systemcfg
389  * structures
390  * (at least until we get rid of them completely). This is mostly some
391  * cache informations about the CPU that will be used by cache flush
392  * routines and/or provided to userland
393  */
394 static void __init initialize_cache_info(void)
395 {
396 	struct device_node *np;
397 	unsigned long num_cpus = 0;
398 
399 	DBG(" -> initialize_cache_info()\n");
400 
401 	for_each_node_by_type(np, "cpu") {
402 		num_cpus += 1;
403 
404 		/*
405 		 * We're assuming *all* of the CPUs have the same
406 		 * d-cache and i-cache sizes... -Peter
407 		 */
408 		if (num_cpus == 1) {
409 			const __be32 *sizep, *lsizep;
410 			u32 size, lsize;
411 
412 			size = 0;
413 			lsize = cur_cpu_spec->dcache_bsize;
414 			sizep = of_get_property(np, "d-cache-size", NULL);
415 			if (sizep != NULL)
416 				size = be32_to_cpu(*sizep);
417 			lsizep = of_get_property(np, "d-cache-block-size",
418 						 NULL);
419 			/* fallback if block size missing */
420 			if (lsizep == NULL)
421 				lsizep = of_get_property(np,
422 							 "d-cache-line-size",
423 							 NULL);
424 			if (lsizep != NULL)
425 				lsize = be32_to_cpu(*lsizep);
426 			if (sizep == NULL || lsizep == NULL)
427 				DBG("Argh, can't find dcache properties ! "
428 				    "sizep: %p, lsizep: %p\n", sizep, lsizep);
429 
430 			ppc64_caches.dsize = size;
431 			ppc64_caches.dline_size = lsize;
432 			ppc64_caches.log_dline_size = __ilog2(lsize);
433 			ppc64_caches.dlines_per_page = PAGE_SIZE / lsize;
434 
435 			size = 0;
436 			lsize = cur_cpu_spec->icache_bsize;
437 			sizep = of_get_property(np, "i-cache-size", NULL);
438 			if (sizep != NULL)
439 				size = be32_to_cpu(*sizep);
440 			lsizep = of_get_property(np, "i-cache-block-size",
441 						 NULL);
442 			if (lsizep == NULL)
443 				lsizep = of_get_property(np,
444 							 "i-cache-line-size",
445 							 NULL);
446 			if (lsizep != NULL)
447 				lsize = be32_to_cpu(*lsizep);
448 			if (sizep == NULL || lsizep == NULL)
449 				DBG("Argh, can't find icache properties ! "
450 				    "sizep: %p, lsizep: %p\n", sizep, lsizep);
451 
452 			ppc64_caches.isize = size;
453 			ppc64_caches.iline_size = lsize;
454 			ppc64_caches.log_iline_size = __ilog2(lsize);
455 			ppc64_caches.ilines_per_page = PAGE_SIZE / lsize;
456 		}
457 	}
458 
459 	DBG(" <- initialize_cache_info()\n");
460 }
461 
462 
463 /*
464  * Do some initial setup of the system.  The parameters are those which
465  * were passed in from the bootloader.
466  */
467 void __init setup_system(void)
468 {
469 	DBG(" -> setup_system()\n");
470 
471 	/* Apply the CPUs-specific and firmware specific fixups to kernel
472 	 * text (nop out sections not relevant to this CPU or this firmware)
473 	 */
474 	do_feature_fixups(cur_cpu_spec->cpu_features,
475 			  &__start___ftr_fixup, &__stop___ftr_fixup);
476 	do_feature_fixups(cur_cpu_spec->mmu_features,
477 			  &__start___mmu_ftr_fixup, &__stop___mmu_ftr_fixup);
478 	do_feature_fixups(powerpc_firmware_features,
479 			  &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
480 	do_lwsync_fixups(cur_cpu_spec->cpu_features,
481 			 &__start___lwsync_fixup, &__stop___lwsync_fixup);
482 	do_final_fixups();
483 
484 	/*
485 	 * Unflatten the device-tree passed by prom_init or kexec
486 	 */
487 	unflatten_device_tree();
488 
489 	/*
490 	 * Fill the ppc64_caches & systemcfg structures with informations
491  	 * retrieved from the device-tree.
492 	 */
493 	initialize_cache_info();
494 
495 #ifdef CONFIG_PPC_RTAS
496 	/*
497 	 * Initialize RTAS if available
498 	 */
499 	rtas_initialize();
500 #endif /* CONFIG_PPC_RTAS */
501 
502 	/*
503 	 * Check if we have an initrd provided via the device-tree
504 	 */
505 	check_for_initrd();
506 
507 	/*
508 	 * Do some platform specific early initializations, that includes
509 	 * setting up the hash table pointers. It also sets up some interrupt-mapping
510 	 * related options that will be used by finish_device_tree()
511 	 */
512 	if (ppc_md.init_early)
513 		ppc_md.init_early();
514 
515  	/*
516 	 * We can discover serial ports now since the above did setup the
517 	 * hash table management for us, thus ioremap works. We do that early
518 	 * so that further code can be debugged
519 	 */
520 	find_legacy_serial_ports();
521 
522 	/*
523 	 * Register early console
524 	 */
525 	register_early_udbg_console();
526 
527 	/*
528 	 * Initialize xmon
529 	 */
530 	xmon_setup();
531 
532 	smp_setup_cpu_maps();
533 	check_smt_enabled();
534 	setup_tlb_core_data();
535 
536 	/*
537 	 * Freescale Book3e parts spin in a loop provided by firmware,
538 	 * so smp_release_cpus() does nothing for them
539 	 */
540 #if defined(CONFIG_SMP)
541 	/* Release secondary cpus out of their spinloops at 0x60 now that
542 	 * we can map physical -> logical CPU ids
543 	 */
544 	smp_release_cpus();
545 #endif
546 
547 	pr_info("Starting Linux %s %s\n", init_utsname()->machine,
548 		 init_utsname()->version);
549 
550 	pr_info("-----------------------------------------------------\n");
551 	pr_info("ppc64_pft_size    = 0x%llx\n", ppc64_pft_size);
552 	pr_info("phys_mem_size     = 0x%llx\n", memblock_phys_mem_size());
553 
554 	if (ppc64_caches.dline_size != 0x80)
555 		pr_info("dcache_line_size  = 0x%x\n", ppc64_caches.dline_size);
556 	if (ppc64_caches.iline_size != 0x80)
557 		pr_info("icache_line_size  = 0x%x\n", ppc64_caches.iline_size);
558 
559 	pr_info("cpu_features      = 0x%016lx\n", cur_cpu_spec->cpu_features);
560 	pr_info("  possible        = 0x%016lx\n", CPU_FTRS_POSSIBLE);
561 	pr_info("  always          = 0x%016lx\n", CPU_FTRS_ALWAYS);
562 	pr_info("cpu_user_features = 0x%08x 0x%08x\n", cur_cpu_spec->cpu_user_features,
563 		cur_cpu_spec->cpu_user_features2);
564 	pr_info("mmu_features      = 0x%08x\n", cur_cpu_spec->mmu_features);
565 	pr_info("firmware_features = 0x%016lx\n", powerpc_firmware_features);
566 
567 #ifdef CONFIG_PPC_STD_MMU_64
568 	if (htab_address)
569 		pr_info("htab_address      = 0x%p\n", htab_address);
570 
571 	pr_info("htab_hash_mask    = 0x%lx\n", htab_hash_mask);
572 #endif
573 
574 	if (PHYSICAL_START > 0)
575 		pr_info("physical_start    = 0x%llx\n",
576 		       (unsigned long long)PHYSICAL_START);
577 	pr_info("-----------------------------------------------------\n");
578 
579 	DBG(" <- setup_system()\n");
580 }
581 
582 /* This returns the limit below which memory accesses to the linear
583  * mapping are guarnateed not to cause a TLB or SLB miss. This is
584  * used to allocate interrupt or emergency stacks for which our
585  * exception entry path doesn't deal with being interrupted.
586  */
587 static u64 safe_stack_limit(void)
588 {
589 #ifdef CONFIG_PPC_BOOK3E
590 	/* Freescale BookE bolts the entire linear mapping */
591 	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E))
592 		return linear_map_top;
593 	/* Other BookE, we assume the first GB is bolted */
594 	return 1ul << 30;
595 #else
596 	/* BookS, the first segment is bolted */
597 	if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
598 		return 1UL << SID_SHIFT_1T;
599 	return 1UL << SID_SHIFT;
600 #endif
601 }
602 
603 static void __init irqstack_early_init(void)
604 {
605 	u64 limit = safe_stack_limit();
606 	unsigned int i;
607 
608 	/*
609 	 * Interrupt stacks must be in the first segment since we
610 	 * cannot afford to take SLB misses on them.
611 	 */
612 	for_each_possible_cpu(i) {
613 		softirq_ctx[i] = (struct thread_info *)
614 			__va(memblock_alloc_base(THREAD_SIZE,
615 					    THREAD_SIZE, limit));
616 		hardirq_ctx[i] = (struct thread_info *)
617 			__va(memblock_alloc_base(THREAD_SIZE,
618 					    THREAD_SIZE, limit));
619 	}
620 }
621 
622 #ifdef CONFIG_PPC_BOOK3E
623 static void __init exc_lvl_early_init(void)
624 {
625 	unsigned int i;
626 	unsigned long sp;
627 
628 	for_each_possible_cpu(i) {
629 		sp = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
630 		critirq_ctx[i] = (struct thread_info *)__va(sp);
631 		paca[i].crit_kstack = __va(sp + THREAD_SIZE);
632 
633 		sp = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
634 		dbgirq_ctx[i] = (struct thread_info *)__va(sp);
635 		paca[i].dbg_kstack = __va(sp + THREAD_SIZE);
636 
637 		sp = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
638 		mcheckirq_ctx[i] = (struct thread_info *)__va(sp);
639 		paca[i].mc_kstack = __va(sp + THREAD_SIZE);
640 	}
641 
642 	if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
643 		patch_exception(0x040, exc_debug_debug_book3e);
644 }
645 #else
646 #define exc_lvl_early_init()
647 #endif
648 
649 /*
650  * Stack space used when we detect a bad kernel stack pointer, and
651  * early in SMP boots before relocation is enabled. Exclusive emergency
652  * stack for machine checks.
653  */
654 static void __init emergency_stack_init(void)
655 {
656 	u64 limit;
657 	unsigned int i;
658 
659 	/*
660 	 * Emergency stacks must be under 256MB, we cannot afford to take
661 	 * SLB misses on them. The ABI also requires them to be 128-byte
662 	 * aligned.
663 	 *
664 	 * Since we use these as temporary stacks during secondary CPU
665 	 * bringup, we need to get at them in real mode. This means they
666 	 * must also be within the RMO region.
667 	 */
668 	limit = min(safe_stack_limit(), ppc64_rma_size);
669 
670 	for_each_possible_cpu(i) {
671 		struct thread_info *ti;
672 		ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
673 		klp_init_thread_info(ti);
674 		paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
675 
676 #ifdef CONFIG_PPC_BOOK3S_64
677 		/* emergency stack for machine check exception handling. */
678 		ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
679 		klp_init_thread_info(ti);
680 		paca[i].mc_emergency_sp = (void *)ti + THREAD_SIZE;
681 #endif
682 	}
683 }
684 
685 /*
686  * Called into from start_kernel this initializes memblock, which is used
687  * to manage page allocation until mem_init is called.
688  */
689 void __init setup_arch(char **cmdline_p)
690 {
691 	*cmdline_p = boot_command_line;
692 
693 	/*
694 	 * Set cache line size based on type of cpu as a default.
695 	 * Systems with OF can look in the properties on the cpu node(s)
696 	 * for a possibly more accurate value.
697 	 */
698 	dcache_bsize = ppc64_caches.dline_size;
699 	icache_bsize = ppc64_caches.iline_size;
700 
701 	if (ppc_md.panic)
702 		setup_panic();
703 
704 	klp_init_thread_info(&init_thread_info);
705 
706 	init_mm.start_code = (unsigned long)_stext;
707 	init_mm.end_code = (unsigned long) _etext;
708 	init_mm.end_data = (unsigned long) _edata;
709 	init_mm.brk = klimit;
710 #ifdef CONFIG_PPC_64K_PAGES
711 	init_mm.context.pte_frag = NULL;
712 #endif
713 #ifdef CONFIG_SPAPR_TCE_IOMMU
714 	mm_iommu_init(&init_mm.context);
715 #endif
716 	irqstack_early_init();
717 	exc_lvl_early_init();
718 	emergency_stack_init();
719 
720 	initmem_init();
721 
722 #ifdef CONFIG_DUMMY_CONSOLE
723 	conswitchp = &dummy_con;
724 #endif
725 
726 	if (ppc_md.setup_arch)
727 		ppc_md.setup_arch();
728 
729 	paging_init();
730 
731 	/* Initialize the MMU context management stuff */
732 	mmu_context_init();
733 
734 	/* Interrupt code needs to be 64K-aligned */
735 	if ((unsigned long)_stext & 0xffff)
736 		panic("Kernelbase not 64K-aligned (0x%lx)!\n",
737 		      (unsigned long)_stext);
738 }
739 
740 #ifdef CONFIG_SMP
741 #define PCPU_DYN_SIZE		()
742 
743 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
744 {
745 	return __alloc_bootmem_node(NODE_DATA(cpu_to_node(cpu)), size, align,
746 				    __pa(MAX_DMA_ADDRESS));
747 }
748 
749 static void __init pcpu_fc_free(void *ptr, size_t size)
750 {
751 	free_bootmem(__pa(ptr), size);
752 }
753 
754 static int pcpu_cpu_distance(unsigned int from, unsigned int to)
755 {
756 	if (cpu_to_node(from) == cpu_to_node(to))
757 		return LOCAL_DISTANCE;
758 	else
759 		return REMOTE_DISTANCE;
760 }
761 
762 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
763 EXPORT_SYMBOL(__per_cpu_offset);
764 
765 void __init setup_per_cpu_areas(void)
766 {
767 	const size_t dyn_size = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
768 	size_t atom_size;
769 	unsigned long delta;
770 	unsigned int cpu;
771 	int rc;
772 
773 	/*
774 	 * Linear mapping is one of 4K, 1M and 16M.  For 4K, no need
775 	 * to group units.  For larger mappings, use 1M atom which
776 	 * should be large enough to contain a number of units.
777 	 */
778 	if (mmu_linear_psize == MMU_PAGE_4K)
779 		atom_size = PAGE_SIZE;
780 	else
781 		atom_size = 1 << 20;
782 
783 	rc = pcpu_embed_first_chunk(0, dyn_size, atom_size, pcpu_cpu_distance,
784 				    pcpu_fc_alloc, pcpu_fc_free);
785 	if (rc < 0)
786 		panic("cannot initialize percpu area (err=%d)", rc);
787 
788 	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
789 	for_each_possible_cpu(cpu) {
790                 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
791 		paca[cpu].data_offset = __per_cpu_offset[cpu];
792 	}
793 }
794 #endif
795 
796 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
797 unsigned long memory_block_size_bytes(void)
798 {
799 	if (ppc_md.memory_block_size)
800 		return ppc_md.memory_block_size();
801 
802 	return MIN_MEMORY_BLOCK_SIZE;
803 }
804 #endif
805 
806 #if defined(CONFIG_PPC_INDIRECT_PIO) || defined(CONFIG_PPC_INDIRECT_MMIO)
807 struct ppc_pci_io ppc_pci_io;
808 EXPORT_SYMBOL(ppc_pci_io);
809 #endif
810 
811 #ifdef CONFIG_HARDLOCKUP_DETECTOR
812 u64 hw_nmi_get_sample_period(int watchdog_thresh)
813 {
814 	return ppc_proc_freq * watchdog_thresh;
815 }
816 
817 /*
818  * The hardlockup detector breaks PMU event based branches and is likely
819  * to get false positives in KVM guests, so disable it by default.
820  */
821 static int __init disable_hardlockup_detector(void)
822 {
823 	hardlockup_detector_disable();
824 
825 	return 0;
826 }
827 early_initcall(disable_hardlockup_detector);
828 #endif
829