xref: /openbmc/linux/arch/powerpc/kernel/setup_64.c (revision ca55b2fe)
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 
73 #ifdef DEBUG
74 #define DBG(fmt...) udbg_printf(fmt)
75 #else
76 #define DBG(fmt...)
77 #endif
78 
79 int spinning_secondaries;
80 u64 ppc64_pft_size;
81 
82 /* Pick defaults since we might want to patch instructions
83  * before we've read this from the device tree.
84  */
85 struct ppc64_caches ppc64_caches = {
86 	.dline_size = 0x40,
87 	.log_dline_size = 6,
88 	.iline_size = 0x40,
89 	.log_iline_size = 6
90 };
91 EXPORT_SYMBOL_GPL(ppc64_caches);
92 
93 /*
94  * These are used in binfmt_elf.c to put aux entries on the stack
95  * for each elf executable being started.
96  */
97 int dcache_bsize;
98 int icache_bsize;
99 int ucache_bsize;
100 
101 #if defined(CONFIG_PPC_BOOK3E) && defined(CONFIG_SMP)
102 static void setup_tlb_core_data(void)
103 {
104 	int cpu;
105 
106 	BUILD_BUG_ON(offsetof(struct tlb_core_data, lock) != 0);
107 
108 	for_each_possible_cpu(cpu) {
109 		int first = cpu_first_thread_sibling(cpu);
110 
111 		paca[cpu].tcd_ptr = &paca[first].tcd;
112 
113 		/*
114 		 * If we have threads, we need either tlbsrx.
115 		 * or e6500 tablewalk mode, or else TLB handlers
116 		 * will be racy and could produce duplicate entries.
117 		 */
118 		if (smt_enabled_at_boot >= 2 &&
119 		    !mmu_has_feature(MMU_FTR_USE_TLBRSRV) &&
120 		    book3e_htw_mode != PPC_HTW_E6500) {
121 			/* Should we panic instead? */
122 			WARN_ONCE("%s: unsupported MMU configuration -- expect problems\n",
123 				  __func__);
124 		}
125 	}
126 }
127 #else
128 static void setup_tlb_core_data(void)
129 {
130 }
131 #endif
132 
133 #ifdef CONFIG_SMP
134 
135 static char *smt_enabled_cmdline;
136 
137 /* Look for ibm,smt-enabled OF option */
138 static void check_smt_enabled(void)
139 {
140 	struct device_node *dn;
141 	const char *smt_option;
142 
143 	/* Default to enabling all threads */
144 	smt_enabled_at_boot = threads_per_core;
145 
146 	/* Allow the command line to overrule the OF option */
147 	if (smt_enabled_cmdline) {
148 		if (!strcmp(smt_enabled_cmdline, "on"))
149 			smt_enabled_at_boot = threads_per_core;
150 		else if (!strcmp(smt_enabled_cmdline, "off"))
151 			smt_enabled_at_boot = 0;
152 		else {
153 			int smt;
154 			int rc;
155 
156 			rc = kstrtoint(smt_enabled_cmdline, 10, &smt);
157 			if (!rc)
158 				smt_enabled_at_boot =
159 					min(threads_per_core, smt);
160 		}
161 	} else {
162 		dn = of_find_node_by_path("/options");
163 		if (dn) {
164 			smt_option = of_get_property(dn, "ibm,smt-enabled",
165 						     NULL);
166 
167 			if (smt_option) {
168 				if (!strcmp(smt_option, "on"))
169 					smt_enabled_at_boot = threads_per_core;
170 				else if (!strcmp(smt_option, "off"))
171 					smt_enabled_at_boot = 0;
172 			}
173 
174 			of_node_put(dn);
175 		}
176 	}
177 }
178 
179 /* Look for smt-enabled= cmdline option */
180 static int __init early_smt_enabled(char *p)
181 {
182 	smt_enabled_cmdline = p;
183 	return 0;
184 }
185 early_param("smt-enabled", early_smt_enabled);
186 
187 #else
188 #define check_smt_enabled()
189 #endif /* CONFIG_SMP */
190 
191 /** Fix up paca fields required for the boot cpu */
192 static void fixup_boot_paca(void)
193 {
194 	/* The boot cpu is started */
195 	get_paca()->cpu_start = 1;
196 	/* Allow percpu accesses to work until we setup percpu data */
197 	get_paca()->data_offset = 0;
198 }
199 
200 static void cpu_ready_for_interrupts(void)
201 {
202 	/* Set IR and DR in PACA MSR */
203 	get_paca()->kernel_msr = MSR_KERNEL;
204 
205 	/*
206 	 * Enable AIL if supported, and we are in hypervisor mode. If we are
207 	 * not in hypervisor mode, we enable relocation-on interrupts later
208 	 * in pSeries_setup_arch() using the H_SET_MODE hcall.
209 	 */
210 	if (cpu_has_feature(CPU_FTR_HVMODE) &&
211 	    cpu_has_feature(CPU_FTR_ARCH_207S)) {
212 		unsigned long lpcr = mfspr(SPRN_LPCR);
213 		mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
214 	}
215 }
216 
217 /*
218  * Early initialization entry point. This is called by head.S
219  * with MMU translation disabled. We rely on the "feature" of
220  * the CPU that ignores the top 2 bits of the address in real
221  * mode so we can access kernel globals normally provided we
222  * only toy with things in the RMO region. From here, we do
223  * some early parsing of the device-tree to setup out MEMBLOCK
224  * data structures, and allocate & initialize the hash table
225  * and segment tables so we can start running with translation
226  * enabled.
227  *
228  * It is this function which will call the probe() callback of
229  * the various platform types and copy the matching one to the
230  * global ppc_md structure. Your platform can eventually do
231  * some very early initializations from the probe() routine, but
232  * this is not recommended, be very careful as, for example, the
233  * device-tree is not accessible via normal means at this point.
234  */
235 
236 void __init early_setup(unsigned long dt_ptr)
237 {
238 	static __initdata struct paca_struct boot_paca;
239 
240 	/* -------- printk is _NOT_ safe to use here ! ------- */
241 
242 	/* Identify CPU type */
243 	identify_cpu(0, mfspr(SPRN_PVR));
244 
245 	/* Assume we're on cpu 0 for now. Don't write to the paca yet! */
246 	initialise_paca(&boot_paca, 0);
247 	setup_paca(&boot_paca);
248 	fixup_boot_paca();
249 
250 	/* Initialize lockdep early or else spinlocks will blow */
251 	lockdep_init();
252 
253 	/* -------- printk is now safe to use ------- */
254 
255 	/* Enable early debugging if any specified (see udbg.h) */
256 	udbg_early_init();
257 
258  	DBG(" -> early_setup(), dt_ptr: 0x%lx\n", dt_ptr);
259 
260 	/*
261 	 * Do early initialization using the flattened device
262 	 * tree, such as retrieving the physical memory map or
263 	 * calculating/retrieving the hash table size.
264 	 */
265 	early_init_devtree(__va(dt_ptr));
266 
267 	epapr_paravirt_early_init();
268 
269 	/* Now we know the logical id of our boot cpu, setup the paca. */
270 	setup_paca(&paca[boot_cpuid]);
271 	fixup_boot_paca();
272 
273 	/* Probe the machine type */
274 	probe_machine();
275 
276 	setup_kdump_trampoline();
277 
278 	DBG("Found, Initializing memory management...\n");
279 
280 	/* Initialize the hash table or TLB handling */
281 	early_init_mmu();
282 
283 	/*
284 	 * At this point, we can let interrupts switch to virtual mode
285 	 * (the MMU has been setup), so adjust the MSR in the PACA to
286 	 * have IR and DR set and enable AIL if it exists
287 	 */
288 	cpu_ready_for_interrupts();
289 
290 	/* Reserve large chunks of memory for use by CMA for KVM */
291 	kvm_cma_reserve();
292 
293 	/*
294 	 * Reserve any gigantic pages requested on the command line.
295 	 * memblock needs to have been initialized by the time this is
296 	 * called since this will reserve memory.
297 	 */
298 	reserve_hugetlb_gpages();
299 
300 	DBG(" <- early_setup()\n");
301 
302 #ifdef CONFIG_PPC_EARLY_DEBUG_BOOTX
303 	/*
304 	 * This needs to be done *last* (after the above DBG() even)
305 	 *
306 	 * Right after we return from this function, we turn on the MMU
307 	 * which means the real-mode access trick that btext does will
308 	 * no longer work, it needs to switch to using a real MMU
309 	 * mapping. This call will ensure that it does
310 	 */
311 	btext_map();
312 #endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */
313 }
314 
315 #ifdef CONFIG_SMP
316 void early_setup_secondary(void)
317 {
318 	/* Mark interrupts enabled in PACA */
319 	get_paca()->soft_enabled = 0;
320 
321 	/* Initialize the hash table or TLB handling */
322 	early_init_mmu_secondary();
323 
324 	/*
325 	 * At this point, we can let interrupts switch to virtual mode
326 	 * (the MMU has been setup), so adjust the MSR in the PACA to
327 	 * have IR and DR set.
328 	 */
329 	cpu_ready_for_interrupts();
330 }
331 
332 #endif /* CONFIG_SMP */
333 
334 #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
335 void smp_release_cpus(void)
336 {
337 	unsigned long *ptr;
338 	int i;
339 
340 	DBG(" -> smp_release_cpus()\n");
341 
342 	/* All secondary cpus are spinning on a common spinloop, release them
343 	 * all now so they can start to spin on their individual paca
344 	 * spinloops. For non SMP kernels, the secondary cpus never get out
345 	 * of the common spinloop.
346 	 */
347 
348 	ptr  = (unsigned long *)((unsigned long)&__secondary_hold_spinloop
349 			- PHYSICAL_START);
350 	*ptr = ppc_function_entry(generic_secondary_smp_init);
351 
352 	/* And wait a bit for them to catch up */
353 	for (i = 0; i < 100000; i++) {
354 		mb();
355 		HMT_low();
356 		if (spinning_secondaries == 0)
357 			break;
358 		udelay(1);
359 	}
360 	DBG("spinning_secondaries = %d\n", spinning_secondaries);
361 
362 	DBG(" <- smp_release_cpus()\n");
363 }
364 #endif /* CONFIG_SMP || CONFIG_KEXEC */
365 
366 /*
367  * Initialize some remaining members of the ppc64_caches and systemcfg
368  * structures
369  * (at least until we get rid of them completely). This is mostly some
370  * cache informations about the CPU that will be used by cache flush
371  * routines and/or provided to userland
372  */
373 static void __init initialize_cache_info(void)
374 {
375 	struct device_node *np;
376 	unsigned long num_cpus = 0;
377 
378 	DBG(" -> initialize_cache_info()\n");
379 
380 	for_each_node_by_type(np, "cpu") {
381 		num_cpus += 1;
382 
383 		/*
384 		 * We're assuming *all* of the CPUs have the same
385 		 * d-cache and i-cache sizes... -Peter
386 		 */
387 		if (num_cpus == 1) {
388 			const __be32 *sizep, *lsizep;
389 			u32 size, lsize;
390 
391 			size = 0;
392 			lsize = cur_cpu_spec->dcache_bsize;
393 			sizep = of_get_property(np, "d-cache-size", NULL);
394 			if (sizep != NULL)
395 				size = be32_to_cpu(*sizep);
396 			lsizep = of_get_property(np, "d-cache-block-size",
397 						 NULL);
398 			/* fallback if block size missing */
399 			if (lsizep == NULL)
400 				lsizep = of_get_property(np,
401 							 "d-cache-line-size",
402 							 NULL);
403 			if (lsizep != NULL)
404 				lsize = be32_to_cpu(*lsizep);
405 			if (sizep == NULL || lsizep == NULL)
406 				DBG("Argh, can't find dcache properties ! "
407 				    "sizep: %p, lsizep: %p\n", sizep, lsizep);
408 
409 			ppc64_caches.dsize = size;
410 			ppc64_caches.dline_size = lsize;
411 			ppc64_caches.log_dline_size = __ilog2(lsize);
412 			ppc64_caches.dlines_per_page = PAGE_SIZE / lsize;
413 
414 			size = 0;
415 			lsize = cur_cpu_spec->icache_bsize;
416 			sizep = of_get_property(np, "i-cache-size", NULL);
417 			if (sizep != NULL)
418 				size = be32_to_cpu(*sizep);
419 			lsizep = of_get_property(np, "i-cache-block-size",
420 						 NULL);
421 			if (lsizep == NULL)
422 				lsizep = of_get_property(np,
423 							 "i-cache-line-size",
424 							 NULL);
425 			if (lsizep != NULL)
426 				lsize = be32_to_cpu(*lsizep);
427 			if (sizep == NULL || lsizep == NULL)
428 				DBG("Argh, can't find icache properties ! "
429 				    "sizep: %p, lsizep: %p\n", sizep, lsizep);
430 
431 			ppc64_caches.isize = size;
432 			ppc64_caches.iline_size = lsize;
433 			ppc64_caches.log_iline_size = __ilog2(lsize);
434 			ppc64_caches.ilines_per_page = PAGE_SIZE / lsize;
435 		}
436 	}
437 
438 	DBG(" <- initialize_cache_info()\n");
439 }
440 
441 
442 /*
443  * Do some initial setup of the system.  The parameters are those which
444  * were passed in from the bootloader.
445  */
446 void __init setup_system(void)
447 {
448 	DBG(" -> setup_system()\n");
449 
450 	/* Apply the CPUs-specific and firmware specific fixups to kernel
451 	 * text (nop out sections not relevant to this CPU or this firmware)
452 	 */
453 	do_feature_fixups(cur_cpu_spec->cpu_features,
454 			  &__start___ftr_fixup, &__stop___ftr_fixup);
455 	do_feature_fixups(cur_cpu_spec->mmu_features,
456 			  &__start___mmu_ftr_fixup, &__stop___mmu_ftr_fixup);
457 	do_feature_fixups(powerpc_firmware_features,
458 			  &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
459 	do_lwsync_fixups(cur_cpu_spec->cpu_features,
460 			 &__start___lwsync_fixup, &__stop___lwsync_fixup);
461 	do_final_fixups();
462 
463 	/*
464 	 * Unflatten the device-tree passed by prom_init or kexec
465 	 */
466 	unflatten_device_tree();
467 
468 	/*
469 	 * Fill the ppc64_caches & systemcfg structures with informations
470  	 * retrieved from the device-tree.
471 	 */
472 	initialize_cache_info();
473 
474 #ifdef CONFIG_PPC_RTAS
475 	/*
476 	 * Initialize RTAS if available
477 	 */
478 	rtas_initialize();
479 #endif /* CONFIG_PPC_RTAS */
480 
481 	/*
482 	 * Check if we have an initrd provided via the device-tree
483 	 */
484 	check_for_initrd();
485 
486 	/*
487 	 * Do some platform specific early initializations, that includes
488 	 * setting up the hash table pointers. It also sets up some interrupt-mapping
489 	 * related options that will be used by finish_device_tree()
490 	 */
491 	if (ppc_md.init_early)
492 		ppc_md.init_early();
493 
494  	/*
495 	 * We can discover serial ports now since the above did setup the
496 	 * hash table management for us, thus ioremap works. We do that early
497 	 * so that further code can be debugged
498 	 */
499 	find_legacy_serial_ports();
500 
501 	/*
502 	 * Register early console
503 	 */
504 	register_early_udbg_console();
505 
506 	/*
507 	 * Initialize xmon
508 	 */
509 	xmon_setup();
510 
511 	smp_setup_cpu_maps();
512 	check_smt_enabled();
513 	setup_tlb_core_data();
514 
515 	/*
516 	 * Freescale Book3e parts spin in a loop provided by firmware,
517 	 * so smp_release_cpus() does nothing for them
518 	 */
519 #if defined(CONFIG_SMP) && !defined(CONFIG_PPC_FSL_BOOK3E)
520 	/* Release secondary cpus out of their spinloops at 0x60 now that
521 	 * we can map physical -> logical CPU ids
522 	 */
523 	smp_release_cpus();
524 #endif
525 
526 	pr_info("Starting Linux %s %s\n", init_utsname()->machine,
527 		 init_utsname()->version);
528 
529 	pr_info("-----------------------------------------------------\n");
530 	pr_info("ppc64_pft_size    = 0x%llx\n", ppc64_pft_size);
531 	pr_info("phys_mem_size     = 0x%llx\n", memblock_phys_mem_size());
532 
533 	if (ppc64_caches.dline_size != 0x80)
534 		pr_info("dcache_line_size  = 0x%x\n", ppc64_caches.dline_size);
535 	if (ppc64_caches.iline_size != 0x80)
536 		pr_info("icache_line_size  = 0x%x\n", ppc64_caches.iline_size);
537 
538 	pr_info("cpu_features      = 0x%016lx\n", cur_cpu_spec->cpu_features);
539 	pr_info("  possible        = 0x%016lx\n", CPU_FTRS_POSSIBLE);
540 	pr_info("  always          = 0x%016lx\n", CPU_FTRS_ALWAYS);
541 	pr_info("cpu_user_features = 0x%08x 0x%08x\n", cur_cpu_spec->cpu_user_features,
542 		cur_cpu_spec->cpu_user_features2);
543 	pr_info("mmu_features      = 0x%08x\n", cur_cpu_spec->mmu_features);
544 	pr_info("firmware_features = 0x%016lx\n", powerpc_firmware_features);
545 
546 #ifdef CONFIG_PPC_STD_MMU_64
547 	if (htab_address)
548 		pr_info("htab_address      = 0x%p\n", htab_address);
549 
550 	pr_info("htab_hash_mask    = 0x%lx\n", htab_hash_mask);
551 #endif
552 
553 	if (PHYSICAL_START > 0)
554 		pr_info("physical_start    = 0x%llx\n",
555 		       (unsigned long long)PHYSICAL_START);
556 	pr_info("-----------------------------------------------------\n");
557 
558 	DBG(" <- setup_system()\n");
559 }
560 
561 /* This returns the limit below which memory accesses to the linear
562  * mapping are guarnateed not to cause a TLB or SLB miss. This is
563  * used to allocate interrupt or emergency stacks for which our
564  * exception entry path doesn't deal with being interrupted.
565  */
566 static u64 safe_stack_limit(void)
567 {
568 #ifdef CONFIG_PPC_BOOK3E
569 	/* Freescale BookE bolts the entire linear mapping */
570 	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E))
571 		return linear_map_top;
572 	/* Other BookE, we assume the first GB is bolted */
573 	return 1ul << 30;
574 #else
575 	/* BookS, the first segment is bolted */
576 	if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
577 		return 1UL << SID_SHIFT_1T;
578 	return 1UL << SID_SHIFT;
579 #endif
580 }
581 
582 static void __init irqstack_early_init(void)
583 {
584 	u64 limit = safe_stack_limit();
585 	unsigned int i;
586 
587 	/*
588 	 * Interrupt stacks must be in the first segment since we
589 	 * cannot afford to take SLB misses on them.
590 	 */
591 	for_each_possible_cpu(i) {
592 		softirq_ctx[i] = (struct thread_info *)
593 			__va(memblock_alloc_base(THREAD_SIZE,
594 					    THREAD_SIZE, limit));
595 		hardirq_ctx[i] = (struct thread_info *)
596 			__va(memblock_alloc_base(THREAD_SIZE,
597 					    THREAD_SIZE, limit));
598 	}
599 }
600 
601 #ifdef CONFIG_PPC_BOOK3E
602 static void __init exc_lvl_early_init(void)
603 {
604 	unsigned int i;
605 	unsigned long sp;
606 
607 	for_each_possible_cpu(i) {
608 		sp = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
609 		critirq_ctx[i] = (struct thread_info *)__va(sp);
610 		paca[i].crit_kstack = __va(sp + THREAD_SIZE);
611 
612 		sp = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
613 		dbgirq_ctx[i] = (struct thread_info *)__va(sp);
614 		paca[i].dbg_kstack = __va(sp + THREAD_SIZE);
615 
616 		sp = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
617 		mcheckirq_ctx[i] = (struct thread_info *)__va(sp);
618 		paca[i].mc_kstack = __va(sp + THREAD_SIZE);
619 	}
620 
621 	if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
622 		patch_exception(0x040, exc_debug_debug_book3e);
623 }
624 #else
625 #define exc_lvl_early_init()
626 #endif
627 
628 /*
629  * Stack space used when we detect a bad kernel stack pointer, and
630  * early in SMP boots before relocation is enabled. Exclusive emergency
631  * stack for machine checks.
632  */
633 static void __init emergency_stack_init(void)
634 {
635 	u64 limit;
636 	unsigned int i;
637 
638 	/*
639 	 * Emergency stacks must be under 256MB, we cannot afford to take
640 	 * SLB misses on them. The ABI also requires them to be 128-byte
641 	 * aligned.
642 	 *
643 	 * Since we use these as temporary stacks during secondary CPU
644 	 * bringup, we need to get at them in real mode. This means they
645 	 * must also be within the RMO region.
646 	 */
647 	limit = min(safe_stack_limit(), ppc64_rma_size);
648 
649 	for_each_possible_cpu(i) {
650 		unsigned long sp;
651 		sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
652 		sp += THREAD_SIZE;
653 		paca[i].emergency_sp = __va(sp);
654 
655 #ifdef CONFIG_PPC_BOOK3S_64
656 		/* emergency stack for machine check exception handling. */
657 		sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
658 		sp += THREAD_SIZE;
659 		paca[i].mc_emergency_sp = __va(sp);
660 #endif
661 	}
662 }
663 
664 /*
665  * Called into from start_kernel this initializes memblock, which is used
666  * to manage page allocation until mem_init is called.
667  */
668 void __init setup_arch(char **cmdline_p)
669 {
670 	*cmdline_p = boot_command_line;
671 
672 	/*
673 	 * Set cache line size based on type of cpu as a default.
674 	 * Systems with OF can look in the properties on the cpu node(s)
675 	 * for a possibly more accurate value.
676 	 */
677 	dcache_bsize = ppc64_caches.dline_size;
678 	icache_bsize = ppc64_caches.iline_size;
679 
680 	if (ppc_md.panic)
681 		setup_panic();
682 
683 	init_mm.start_code = (unsigned long)_stext;
684 	init_mm.end_code = (unsigned long) _etext;
685 	init_mm.end_data = (unsigned long) _edata;
686 	init_mm.brk = klimit;
687 #ifdef CONFIG_PPC_64K_PAGES
688 	init_mm.context.pte_frag = NULL;
689 #endif
690 #ifdef CONFIG_SPAPR_TCE_IOMMU
691 	mm_iommu_init(&init_mm.context);
692 #endif
693 	irqstack_early_init();
694 	exc_lvl_early_init();
695 	emergency_stack_init();
696 
697 	initmem_init();
698 
699 #ifdef CONFIG_DUMMY_CONSOLE
700 	conswitchp = &dummy_con;
701 #endif
702 
703 	if (ppc_md.setup_arch)
704 		ppc_md.setup_arch();
705 
706 	paging_init();
707 
708 	/* Initialize the MMU context management stuff */
709 	mmu_context_init();
710 
711 	/* Interrupt code needs to be 64K-aligned */
712 	if ((unsigned long)_stext & 0xffff)
713 		panic("Kernelbase not 64K-aligned (0x%lx)!\n",
714 		      (unsigned long)_stext);
715 }
716 
717 #ifdef CONFIG_SMP
718 #define PCPU_DYN_SIZE		()
719 
720 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
721 {
722 	return __alloc_bootmem_node(NODE_DATA(cpu_to_node(cpu)), size, align,
723 				    __pa(MAX_DMA_ADDRESS));
724 }
725 
726 static void __init pcpu_fc_free(void *ptr, size_t size)
727 {
728 	free_bootmem(__pa(ptr), size);
729 }
730 
731 static int pcpu_cpu_distance(unsigned int from, unsigned int to)
732 {
733 	if (cpu_to_node(from) == cpu_to_node(to))
734 		return LOCAL_DISTANCE;
735 	else
736 		return REMOTE_DISTANCE;
737 }
738 
739 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
740 EXPORT_SYMBOL(__per_cpu_offset);
741 
742 void __init setup_per_cpu_areas(void)
743 {
744 	const size_t dyn_size = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
745 	size_t atom_size;
746 	unsigned long delta;
747 	unsigned int cpu;
748 	int rc;
749 
750 	/*
751 	 * Linear mapping is one of 4K, 1M and 16M.  For 4K, no need
752 	 * to group units.  For larger mappings, use 1M atom which
753 	 * should be large enough to contain a number of units.
754 	 */
755 	if (mmu_linear_psize == MMU_PAGE_4K)
756 		atom_size = PAGE_SIZE;
757 	else
758 		atom_size = 1 << 20;
759 
760 	rc = pcpu_embed_first_chunk(0, dyn_size, atom_size, pcpu_cpu_distance,
761 				    pcpu_fc_alloc, pcpu_fc_free);
762 	if (rc < 0)
763 		panic("cannot initialize percpu area (err=%d)", rc);
764 
765 	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
766 	for_each_possible_cpu(cpu) {
767                 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
768 		paca[cpu].data_offset = __per_cpu_offset[cpu];
769 	}
770 }
771 #endif
772 
773 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
774 unsigned long memory_block_size_bytes(void)
775 {
776 	if (ppc_md.memory_block_size)
777 		return ppc_md.memory_block_size();
778 
779 	return MIN_MEMORY_BLOCK_SIZE;
780 }
781 #endif
782 
783 #if defined(CONFIG_PPC_INDIRECT_PIO) || defined(CONFIG_PPC_INDIRECT_MMIO)
784 struct ppc_pci_io ppc_pci_io;
785 EXPORT_SYMBOL(ppc_pci_io);
786 #endif
787 
788 #ifdef CONFIG_HARDLOCKUP_DETECTOR
789 u64 hw_nmi_get_sample_period(int watchdog_thresh)
790 {
791 	return ppc_proc_freq * watchdog_thresh;
792 }
793 
794 /*
795  * The hardlockup detector breaks PMU event based branches and is likely
796  * to get false positives in KVM guests, so disable it by default.
797  */
798 static int __init disable_hardlockup_detector(void)
799 {
800 	hardlockup_detector_disable();
801 
802 	return 0;
803 }
804 early_initcall(disable_hardlockup_detector);
805 #endif
806