1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Common boot and setup code for both 32-bit and 64-bit.
4  * Extracted from arch/powerpc/kernel/setup_64.c.
5  *
6  * Copyright (C) 2001 PPC64 Team, IBM Corp
7  */
8 
9 #undef DEBUG
10 
11 #include <linux/export.h>
12 #include <linux/panic_notifier.h>
13 #include <linux/string.h>
14 #include <linux/sched.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/reboot.h>
18 #include <linux/delay.h>
19 #include <linux/initrd.h>
20 #include <linux/platform_device.h>
21 #include <linux/seq_file.h>
22 #include <linux/ioport.h>
23 #include <linux/console.h>
24 #include <linux/screen_info.h>
25 #include <linux/root_dev.h>
26 #include <linux/cpu.h>
27 #include <linux/unistd.h>
28 #include <linux/serial.h>
29 #include <linux/serial_8250.h>
30 #include <linux/percpu.h>
31 #include <linux/memblock.h>
32 #include <linux/of_irq.h>
33 #include <linux/of_fdt.h>
34 #include <linux/of_platform.h>
35 #include <linux/hugetlb.h>
36 #include <linux/pgtable.h>
37 #include <asm/io.h>
38 #include <asm/paca.h>
39 #include <asm/processor.h>
40 #include <asm/vdso_datapage.h>
41 #include <asm/smp.h>
42 #include <asm/elf.h>
43 #include <asm/machdep.h>
44 #include <asm/time.h>
45 #include <asm/cputable.h>
46 #include <asm/sections.h>
47 #include <asm/firmware.h>
48 #include <asm/btext.h>
49 #include <asm/nvram.h>
50 #include <asm/setup.h>
51 #include <asm/rtas.h>
52 #include <asm/iommu.h>
53 #include <asm/serial.h>
54 #include <asm/cache.h>
55 #include <asm/page.h>
56 #include <asm/mmu.h>
57 #include <asm/xmon.h>
58 #include <asm/cputhreads.h>
59 #include <mm/mmu_decl.h>
60 #include <asm/fadump.h>
61 #include <asm/udbg.h>
62 #include <asm/hugetlb.h>
63 #include <asm/livepatch.h>
64 #include <asm/mmu_context.h>
65 #include <asm/cpu_has_feature.h>
66 #include <asm/kasan.h>
67 #include <asm/mce.h>
68 
69 #include "setup.h"
70 
71 #ifdef DEBUG
72 #define DBG(fmt...) udbg_printf(fmt)
73 #else
74 #define DBG(fmt...)
75 #endif
76 
77 /* The main machine-dep calls structure
78  */
79 struct machdep_calls ppc_md;
80 EXPORT_SYMBOL(ppc_md);
81 struct machdep_calls *machine_id;
82 EXPORT_SYMBOL(machine_id);
83 
84 int boot_cpuid = -1;
85 EXPORT_SYMBOL_GPL(boot_cpuid);
86 
87 /*
88  * These are used in binfmt_elf.c to put aux entries on the stack
89  * for each elf executable being started.
90  */
91 int dcache_bsize;
92 int icache_bsize;
93 
94 /*
95  * This still seems to be needed... -- paulus
96  */
97 struct screen_info screen_info = {
98 	.orig_x = 0,
99 	.orig_y = 25,
100 	.orig_video_cols = 80,
101 	.orig_video_lines = 25,
102 	.orig_video_isVGA = 1,
103 	.orig_video_points = 16
104 };
105 #if defined(CONFIG_FB_VGA16_MODULE)
106 EXPORT_SYMBOL(screen_info);
107 #endif
108 
109 /* Variables required to store legacy IO irq routing */
110 int of_i8042_kbd_irq;
111 EXPORT_SYMBOL_GPL(of_i8042_kbd_irq);
112 int of_i8042_aux_irq;
113 EXPORT_SYMBOL_GPL(of_i8042_aux_irq);
114 
115 #ifdef __DO_IRQ_CANON
116 /* XXX should go elsewhere eventually */
117 int ppc_do_canonicalize_irqs;
118 EXPORT_SYMBOL(ppc_do_canonicalize_irqs);
119 #endif
120 
121 #ifdef CONFIG_CRASH_CORE
122 /* This keeps a track of which one is the crashing cpu. */
123 int crashing_cpu = -1;
124 #endif
125 
126 /* also used by kexec */
127 void machine_shutdown(void)
128 {
129 	/*
130 	 * if fadump is active, cleanup the fadump registration before we
131 	 * shutdown.
132 	 */
133 	fadump_cleanup();
134 
135 	if (ppc_md.machine_shutdown)
136 		ppc_md.machine_shutdown();
137 }
138 
139 static void machine_hang(void)
140 {
141 	pr_emerg("System Halted, OK to turn off power\n");
142 	local_irq_disable();
143 	while (1)
144 		;
145 }
146 
147 void machine_restart(char *cmd)
148 {
149 	machine_shutdown();
150 	if (ppc_md.restart)
151 		ppc_md.restart(cmd);
152 
153 	smp_send_stop();
154 
155 	do_kernel_restart(cmd);
156 	mdelay(1000);
157 
158 	machine_hang();
159 }
160 
161 void machine_power_off(void)
162 {
163 	machine_shutdown();
164 	do_kernel_power_off();
165 	smp_send_stop();
166 	machine_hang();
167 }
168 /* Used by the G5 thermal driver */
169 EXPORT_SYMBOL_GPL(machine_power_off);
170 
171 void (*pm_power_off)(void);
172 EXPORT_SYMBOL_GPL(pm_power_off);
173 
174 void machine_halt(void)
175 {
176 	machine_shutdown();
177 	if (ppc_md.halt)
178 		ppc_md.halt();
179 
180 	smp_send_stop();
181 	machine_hang();
182 }
183 
184 #ifdef CONFIG_SMP
185 DEFINE_PER_CPU(unsigned int, cpu_pvr);
186 #endif
187 
188 static void show_cpuinfo_summary(struct seq_file *m)
189 {
190 	struct device_node *root;
191 	const char *model = NULL;
192 	unsigned long bogosum = 0;
193 	int i;
194 
195 	if (IS_ENABLED(CONFIG_SMP) && IS_ENABLED(CONFIG_PPC32)) {
196 		for_each_online_cpu(i)
197 			bogosum += loops_per_jiffy;
198 		seq_printf(m, "total bogomips\t: %lu.%02lu\n",
199 			   bogosum / (500000 / HZ), bogosum / (5000 / HZ) % 100);
200 	}
201 	seq_printf(m, "timebase\t: %lu\n", ppc_tb_freq);
202 	if (ppc_md.name)
203 		seq_printf(m, "platform\t: %s\n", ppc_md.name);
204 	root = of_find_node_by_path("/");
205 	if (root)
206 		model = of_get_property(root, "model", NULL);
207 	if (model)
208 		seq_printf(m, "model\t\t: %s\n", model);
209 	of_node_put(root);
210 
211 	if (ppc_md.show_cpuinfo != NULL)
212 		ppc_md.show_cpuinfo(m);
213 
214 	/* Display the amount of memory */
215 	if (IS_ENABLED(CONFIG_PPC32))
216 		seq_printf(m, "Memory\t\t: %d MB\n",
217 			   (unsigned int)(total_memory / (1024 * 1024)));
218 }
219 
220 static int show_cpuinfo(struct seq_file *m, void *v)
221 {
222 	unsigned long cpu_id = (unsigned long)v - 1;
223 	unsigned int pvr;
224 	unsigned long proc_freq;
225 	unsigned short maj;
226 	unsigned short min;
227 
228 #ifdef CONFIG_SMP
229 	pvr = per_cpu(cpu_pvr, cpu_id);
230 #else
231 	pvr = mfspr(SPRN_PVR);
232 #endif
233 	maj = (pvr >> 8) & 0xFF;
234 	min = pvr & 0xFF;
235 
236 	seq_printf(m, "processor\t: %lu\ncpu\t\t: ", cpu_id);
237 
238 	if (cur_cpu_spec->pvr_mask && cur_cpu_spec->cpu_name)
239 		seq_puts(m, cur_cpu_spec->cpu_name);
240 	else
241 		seq_printf(m, "unknown (%08x)", pvr);
242 
243 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
244 		seq_puts(m, ", altivec supported");
245 
246 	seq_putc(m, '\n');
247 
248 #ifdef CONFIG_TAU
249 	if (cpu_has_feature(CPU_FTR_TAU)) {
250 		if (IS_ENABLED(CONFIG_TAU_AVERAGE)) {
251 			/* more straightforward, but potentially misleading */
252 			seq_printf(m,  "temperature \t: %u C (uncalibrated)\n",
253 				   cpu_temp(cpu_id));
254 		} else {
255 			/* show the actual temp sensor range */
256 			u32 temp;
257 			temp = cpu_temp_both(cpu_id);
258 			seq_printf(m, "temperature \t: %u-%u C (uncalibrated)\n",
259 				   temp & 0xff, temp >> 16);
260 		}
261 	}
262 #endif /* CONFIG_TAU */
263 
264 	/*
265 	 * Platforms that have variable clock rates, should implement
266 	 * the method ppc_md.get_proc_freq() that reports the clock
267 	 * rate of a given cpu. The rest can use ppc_proc_freq to
268 	 * report the clock rate that is same across all cpus.
269 	 */
270 	if (ppc_md.get_proc_freq)
271 		proc_freq = ppc_md.get_proc_freq(cpu_id);
272 	else
273 		proc_freq = ppc_proc_freq;
274 
275 	if (proc_freq)
276 		seq_printf(m, "clock\t\t: %lu.%06luMHz\n",
277 			   proc_freq / 1000000, proc_freq % 1000000);
278 
279 	/* If we are a Freescale core do a simple check so
280 	 * we don't have to keep adding cases in the future */
281 	if (PVR_VER(pvr) & 0x8000) {
282 		switch (PVR_VER(pvr)) {
283 		case 0x8000:	/* 7441/7450/7451, Voyager */
284 		case 0x8001:	/* 7445/7455, Apollo 6 */
285 		case 0x8002:	/* 7447/7457, Apollo 7 */
286 		case 0x8003:	/* 7447A, Apollo 7 PM */
287 		case 0x8004:	/* 7448, Apollo 8 */
288 		case 0x800c:	/* 7410, Nitro */
289 			maj = ((pvr >> 8) & 0xF);
290 			min = PVR_MIN(pvr);
291 			break;
292 		default:	/* e500/book-e */
293 			maj = PVR_MAJ(pvr);
294 			min = PVR_MIN(pvr);
295 			break;
296 		}
297 	} else {
298 		switch (PVR_VER(pvr)) {
299 			case 0x1008:	/* 740P/750P ?? */
300 				maj = ((pvr >> 8) & 0xFF) - 1;
301 				min = pvr & 0xFF;
302 				break;
303 			case 0x004e: /* POWER9 bits 12-15 give chip type */
304 			case 0x0080: /* POWER10 bit 12 gives SMT8/4 */
305 				maj = (pvr >> 8) & 0x0F;
306 				min = pvr & 0xFF;
307 				break;
308 			default:
309 				maj = (pvr >> 8) & 0xFF;
310 				min = pvr & 0xFF;
311 				break;
312 		}
313 	}
314 
315 	seq_printf(m, "revision\t: %hd.%hd (pvr %04x %04x)\n",
316 		   maj, min, PVR_VER(pvr), PVR_REV(pvr));
317 
318 	if (IS_ENABLED(CONFIG_PPC32))
319 		seq_printf(m, "bogomips\t: %lu.%02lu\n", loops_per_jiffy / (500000 / HZ),
320 			   (loops_per_jiffy / (5000 / HZ)) % 100);
321 
322 	seq_putc(m, '\n');
323 
324 	/* If this is the last cpu, print the summary */
325 	if (cpumask_next(cpu_id, cpu_online_mask) >= nr_cpu_ids)
326 		show_cpuinfo_summary(m);
327 
328 	return 0;
329 }
330 
331 static void *c_start(struct seq_file *m, loff_t *pos)
332 {
333 	if (*pos == 0)	/* just in case, cpu 0 is not the first */
334 		*pos = cpumask_first(cpu_online_mask);
335 	else
336 		*pos = cpumask_next(*pos - 1, cpu_online_mask);
337 	if ((*pos) < nr_cpu_ids)
338 		return (void *)(unsigned long)(*pos + 1);
339 	return NULL;
340 }
341 
342 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
343 {
344 	(*pos)++;
345 	return c_start(m, pos);
346 }
347 
348 static void c_stop(struct seq_file *m, void *v)
349 {
350 }
351 
352 const struct seq_operations cpuinfo_op = {
353 	.start	= c_start,
354 	.next	= c_next,
355 	.stop	= c_stop,
356 	.show	= show_cpuinfo,
357 };
358 
359 void __init check_for_initrd(void)
360 {
361 #ifdef CONFIG_BLK_DEV_INITRD
362 	DBG(" -> check_for_initrd()  initrd_start=0x%lx  initrd_end=0x%lx\n",
363 	    initrd_start, initrd_end);
364 
365 	/* If we were passed an initrd, set the ROOT_DEV properly if the values
366 	 * look sensible. If not, clear initrd reference.
367 	 */
368 	if (is_kernel_addr(initrd_start) && is_kernel_addr(initrd_end) &&
369 	    initrd_end > initrd_start)
370 		ROOT_DEV = Root_RAM0;
371 	else
372 		initrd_start = initrd_end = 0;
373 
374 	if (initrd_start)
375 		pr_info("Found initrd at 0x%lx:0x%lx\n", initrd_start, initrd_end);
376 
377 	DBG(" <- check_for_initrd()\n");
378 #endif /* CONFIG_BLK_DEV_INITRD */
379 }
380 
381 #ifdef CONFIG_SMP
382 
383 int threads_per_core, threads_per_subcore, threads_shift __read_mostly;
384 cpumask_t threads_core_mask __read_mostly;
385 EXPORT_SYMBOL_GPL(threads_per_core);
386 EXPORT_SYMBOL_GPL(threads_per_subcore);
387 EXPORT_SYMBOL_GPL(threads_shift);
388 EXPORT_SYMBOL_GPL(threads_core_mask);
389 
390 static void __init cpu_init_thread_core_maps(int tpc)
391 {
392 	int i;
393 
394 	threads_per_core = tpc;
395 	threads_per_subcore = tpc;
396 	cpumask_clear(&threads_core_mask);
397 
398 	/* This implementation only supports power of 2 number of threads
399 	 * for simplicity and performance
400 	 */
401 	threads_shift = ilog2(tpc);
402 	BUG_ON(tpc != (1 << threads_shift));
403 
404 	for (i = 0; i < tpc; i++)
405 		cpumask_set_cpu(i, &threads_core_mask);
406 
407 	printk(KERN_INFO "CPU maps initialized for %d thread%s per core\n",
408 	       tpc, tpc > 1 ? "s" : "");
409 	printk(KERN_DEBUG " (thread shift is %d)\n", threads_shift);
410 }
411 
412 
413 u32 *cpu_to_phys_id = NULL;
414 
415 /**
416  * setup_cpu_maps - initialize the following cpu maps:
417  *                  cpu_possible_mask
418  *                  cpu_present_mask
419  *
420  * Having the possible map set up early allows us to restrict allocations
421  * of things like irqstacks to nr_cpu_ids rather than NR_CPUS.
422  *
423  * We do not initialize the online map here; cpus set their own bits in
424  * cpu_online_mask as they come up.
425  *
426  * This function is valid only for Open Firmware systems.  finish_device_tree
427  * must be called before using this.
428  *
429  * While we're here, we may as well set the "physical" cpu ids in the paca.
430  *
431  * NOTE: This must match the parsing done in early_init_dt_scan_cpus.
432  */
433 void __init smp_setup_cpu_maps(void)
434 {
435 	struct device_node *dn;
436 	int cpu = 0;
437 	int nthreads = 1;
438 
439 	DBG("smp_setup_cpu_maps()\n");
440 
441 	cpu_to_phys_id = memblock_alloc(nr_cpu_ids * sizeof(u32),
442 					__alignof__(u32));
443 	if (!cpu_to_phys_id)
444 		panic("%s: Failed to allocate %zu bytes align=0x%zx\n",
445 		      __func__, nr_cpu_ids * sizeof(u32), __alignof__(u32));
446 
447 	for_each_node_by_type(dn, "cpu") {
448 		const __be32 *intserv;
449 		__be32 cpu_be;
450 		int j, len;
451 
452 		DBG("  * %pOF...\n", dn);
453 
454 		intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s",
455 				&len);
456 		if (intserv) {
457 			DBG("    ibm,ppc-interrupt-server#s -> %lu threads\n",
458 			    (len / sizeof(int)));
459 		} else {
460 			DBG("    no ibm,ppc-interrupt-server#s -> 1 thread\n");
461 			intserv = of_get_property(dn, "reg", &len);
462 			if (!intserv) {
463 				cpu_be = cpu_to_be32(cpu);
464 				/* XXX: what is this? uninitialized?? */
465 				intserv = &cpu_be;	/* assume logical == phys */
466 				len = 4;
467 			}
468 		}
469 
470 		nthreads = len / sizeof(int);
471 
472 		for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
473 			bool avail;
474 
475 			DBG("    thread %d -> cpu %d (hard id %d)\n",
476 			    j, cpu, be32_to_cpu(intserv[j]));
477 
478 			avail = of_device_is_available(dn);
479 			if (!avail)
480 				avail = !of_property_match_string(dn,
481 						"enable-method", "spin-table");
482 
483 			set_cpu_present(cpu, avail);
484 			set_cpu_possible(cpu, true);
485 			cpu_to_phys_id[cpu] = be32_to_cpu(intserv[j]);
486 			cpu++;
487 		}
488 
489 		if (cpu >= nr_cpu_ids) {
490 			of_node_put(dn);
491 			break;
492 		}
493 	}
494 
495 	/* If no SMT supported, nthreads is forced to 1 */
496 	if (!cpu_has_feature(CPU_FTR_SMT)) {
497 		DBG("  SMT disabled ! nthreads forced to 1\n");
498 		nthreads = 1;
499 	}
500 
501 #ifdef CONFIG_PPC64
502 	/*
503 	 * On pSeries LPAR, we need to know how many cpus
504 	 * could possibly be added to this partition.
505 	 */
506 	if (firmware_has_feature(FW_FEATURE_LPAR) &&
507 	    (dn = of_find_node_by_path("/rtas"))) {
508 		int num_addr_cell, num_size_cell, maxcpus;
509 		const __be32 *ireg;
510 
511 		num_addr_cell = of_n_addr_cells(dn);
512 		num_size_cell = of_n_size_cells(dn);
513 
514 		ireg = of_get_property(dn, "ibm,lrdr-capacity", NULL);
515 
516 		if (!ireg)
517 			goto out;
518 
519 		maxcpus = be32_to_cpup(ireg + num_addr_cell + num_size_cell);
520 
521 		/* Double maxcpus for processors which have SMT capability */
522 		if (cpu_has_feature(CPU_FTR_SMT))
523 			maxcpus *= nthreads;
524 
525 		if (maxcpus > nr_cpu_ids) {
526 			printk(KERN_WARNING
527 			       "Partition configured for %d cpus, "
528 			       "operating system maximum is %u.\n",
529 			       maxcpus, nr_cpu_ids);
530 			maxcpus = nr_cpu_ids;
531 		} else
532 			printk(KERN_INFO "Partition configured for %d cpus.\n",
533 			       maxcpus);
534 
535 		for (cpu = 0; cpu < maxcpus; cpu++)
536 			set_cpu_possible(cpu, true);
537 	out:
538 		of_node_put(dn);
539 	}
540 	vdso_data->processorCount = num_present_cpus();
541 #endif /* CONFIG_PPC64 */
542 
543         /* Initialize CPU <=> thread mapping/
544 	 *
545 	 * WARNING: We assume that the number of threads is the same for
546 	 * every CPU in the system. If that is not the case, then some code
547 	 * here will have to be reworked
548 	 */
549 	cpu_init_thread_core_maps(nthreads);
550 
551 	/* Now that possible cpus are set, set nr_cpu_ids for later use */
552 	setup_nr_cpu_ids();
553 
554 	free_unused_pacas();
555 }
556 #endif /* CONFIG_SMP */
557 
558 #ifdef CONFIG_PCSPKR_PLATFORM
559 static __init int add_pcspkr(void)
560 {
561 	struct device_node *np;
562 	struct platform_device *pd;
563 	int ret;
564 
565 	np = of_find_compatible_node(NULL, NULL, "pnpPNP,100");
566 	of_node_put(np);
567 	if (!np)
568 		return -ENODEV;
569 
570 	pd = platform_device_alloc("pcspkr", -1);
571 	if (!pd)
572 		return -ENOMEM;
573 
574 	ret = platform_device_add(pd);
575 	if (ret)
576 		platform_device_put(pd);
577 
578 	return ret;
579 }
580 device_initcall(add_pcspkr);
581 #endif	/* CONFIG_PCSPKR_PLATFORM */
582 
583 static __init void probe_machine(void)
584 {
585 	extern struct machdep_calls __machine_desc_start;
586 	extern struct machdep_calls __machine_desc_end;
587 	unsigned int i;
588 
589 	/*
590 	 * Iterate all ppc_md structures until we find the proper
591 	 * one for the current machine type
592 	 */
593 	DBG("Probing machine type ...\n");
594 
595 	/*
596 	 * Check ppc_md is empty, if not we have a bug, ie, we setup an
597 	 * entry before probe_machine() which will be overwritten
598 	 */
599 	for (i = 0; i < (sizeof(ppc_md) / sizeof(void *)); i++) {
600 		if (((void **)&ppc_md)[i]) {
601 			printk(KERN_ERR "Entry %d in ppc_md non empty before"
602 			       " machine probe !\n", i);
603 		}
604 	}
605 
606 	for (machine_id = &__machine_desc_start;
607 	     machine_id < &__machine_desc_end;
608 	     machine_id++) {
609 		DBG("  %s ...", machine_id->name);
610 		memcpy(&ppc_md, machine_id, sizeof(struct machdep_calls));
611 		if (ppc_md.probe()) {
612 			DBG(" match !\n");
613 			break;
614 		}
615 		DBG("\n");
616 	}
617 	/* What can we do if we didn't find ? */
618 	if (machine_id >= &__machine_desc_end) {
619 		pr_err("No suitable machine description found !\n");
620 		for (;;);
621 	}
622 
623 	printk(KERN_INFO "Using %s machine description\n", ppc_md.name);
624 }
625 
626 /* Match a class of boards, not a specific device configuration. */
627 int check_legacy_ioport(unsigned long base_port)
628 {
629 	struct device_node *parent, *np = NULL;
630 	int ret = -ENODEV;
631 
632 	switch(base_port) {
633 	case I8042_DATA_REG:
634 		if (!(np = of_find_compatible_node(NULL, NULL, "pnpPNP,303")))
635 			np = of_find_compatible_node(NULL, NULL, "pnpPNP,f03");
636 		if (np) {
637 			parent = of_get_parent(np);
638 
639 			of_i8042_kbd_irq = irq_of_parse_and_map(parent, 0);
640 			if (!of_i8042_kbd_irq)
641 				of_i8042_kbd_irq = 1;
642 
643 			of_i8042_aux_irq = irq_of_parse_and_map(parent, 1);
644 			if (!of_i8042_aux_irq)
645 				of_i8042_aux_irq = 12;
646 
647 			of_node_put(np);
648 			np = parent;
649 			break;
650 		}
651 		np = of_find_node_by_type(NULL, "8042");
652 		/* Pegasos has no device_type on its 8042 node, look for the
653 		 * name instead */
654 		if (!np)
655 			np = of_find_node_by_name(NULL, "8042");
656 		if (np) {
657 			of_i8042_kbd_irq = 1;
658 			of_i8042_aux_irq = 12;
659 		}
660 		break;
661 	case FDC_BASE: /* FDC1 */
662 		np = of_find_node_by_type(NULL, "fdc");
663 		break;
664 	default:
665 		/* ipmi is supposed to fail here */
666 		break;
667 	}
668 	if (!np)
669 		return ret;
670 	parent = of_get_parent(np);
671 	if (parent) {
672 		if (of_node_is_type(parent, "isa"))
673 			ret = 0;
674 		of_node_put(parent);
675 	}
676 	of_node_put(np);
677 	return ret;
678 }
679 EXPORT_SYMBOL(check_legacy_ioport);
680 
681 /*
682  * Panic notifiers setup
683  *
684  * We have 3 notifiers for powerpc, each one from a different "nature":
685  *
686  * - ppc_panic_fadump_handler() is a hypervisor notifier, which hard-disables
687  *   IRQs and deal with the Firmware-Assisted dump, when it is configured;
688  *   should run early in the panic path.
689  *
690  * - dump_kernel_offset() is an informative notifier, just showing the KASLR
691  *   offset if we have RANDOMIZE_BASE set.
692  *
693  * - ppc_panic_platform_handler() is a low-level handler that's registered
694  *   only if the platform wishes to perform final actions in the panic path,
695  *   hence it should run late and might not even return. Currently, only
696  *   pseries and ps3 platforms register callbacks.
697  */
698 static int ppc_panic_fadump_handler(struct notifier_block *this,
699 				    unsigned long event, void *ptr)
700 {
701 	/*
702 	 * panic does a local_irq_disable, but we really
703 	 * want interrupts to be hard disabled.
704 	 */
705 	hard_irq_disable();
706 
707 	/*
708 	 * If firmware-assisted dump has been registered then trigger
709 	 * its callback and let the firmware handles everything else.
710 	 */
711 	crash_fadump(NULL, ptr);
712 
713 	return NOTIFY_DONE;
714 }
715 
716 static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
717 			      void *p)
718 {
719 	pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
720 		 kaslr_offset(), KERNELBASE);
721 
722 	return NOTIFY_DONE;
723 }
724 
725 static int ppc_panic_platform_handler(struct notifier_block *this,
726 				      unsigned long event, void *ptr)
727 {
728 	/*
729 	 * This handler is only registered if we have a panic callback
730 	 * on ppc_md, hence NULL check is not needed.
731 	 * Also, it may not return, so it runs really late on panic path.
732 	 */
733 	ppc_md.panic(ptr);
734 
735 	return NOTIFY_DONE;
736 }
737 
738 static struct notifier_block ppc_fadump_block = {
739 	.notifier_call = ppc_panic_fadump_handler,
740 	.priority = INT_MAX, /* run early, to notify the firmware ASAP */
741 };
742 
743 static struct notifier_block kernel_offset_notifier = {
744 	.notifier_call = dump_kernel_offset,
745 };
746 
747 static struct notifier_block ppc_panic_block = {
748 	.notifier_call = ppc_panic_platform_handler,
749 	.priority = INT_MIN, /* may not return; must be done last */
750 };
751 
752 void __init setup_panic(void)
753 {
754 	/* Hard-disables IRQs + deal with FW-assisted dump (fadump) */
755 	atomic_notifier_chain_register(&panic_notifier_list,
756 				       &ppc_fadump_block);
757 
758 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0)
759 		atomic_notifier_chain_register(&panic_notifier_list,
760 					       &kernel_offset_notifier);
761 
762 	/* Low-level platform-specific routines that should run on panic */
763 	if (ppc_md.panic)
764 		atomic_notifier_chain_register(&panic_notifier_list,
765 					       &ppc_panic_block);
766 }
767 
768 #ifdef CONFIG_CHECK_CACHE_COHERENCY
769 /*
770  * For platforms that have configurable cache-coherency.  This function
771  * checks that the cache coherency setting of the kernel matches the setting
772  * left by the firmware, as indicated in the device tree.  Since a mismatch
773  * will eventually result in DMA failures, we print * and error and call
774  * BUG() in that case.
775  */
776 
777 #define KERNEL_COHERENCY	(!IS_ENABLED(CONFIG_NOT_COHERENT_CACHE))
778 
779 static int __init check_cache_coherency(void)
780 {
781 	struct device_node *np;
782 	const void *prop;
783 	bool devtree_coherency;
784 
785 	np = of_find_node_by_path("/");
786 	prop = of_get_property(np, "coherency-off", NULL);
787 	of_node_put(np);
788 
789 	devtree_coherency = prop ? false : true;
790 
791 	if (devtree_coherency != KERNEL_COHERENCY) {
792 		printk(KERN_ERR
793 			"kernel coherency:%s != device tree_coherency:%s\n",
794 			KERNEL_COHERENCY ? "on" : "off",
795 			devtree_coherency ? "on" : "off");
796 		BUG();
797 	}
798 
799 	return 0;
800 }
801 
802 late_initcall(check_cache_coherency);
803 #endif /* CONFIG_CHECK_CACHE_COHERENCY */
804 
805 void ppc_printk_progress(char *s, unsigned short hex)
806 {
807 	pr_info("%s\n", s);
808 }
809 
810 static __init void print_system_info(void)
811 {
812 	pr_info("-----------------------------------------------------\n");
813 	pr_info("phys_mem_size     = 0x%llx\n",
814 		(unsigned long long)memblock_phys_mem_size());
815 
816 	pr_info("dcache_bsize      = 0x%x\n", dcache_bsize);
817 	pr_info("icache_bsize      = 0x%x\n", icache_bsize);
818 
819 	pr_info("cpu_features      = 0x%016lx\n", cur_cpu_spec->cpu_features);
820 	pr_info("  possible        = 0x%016lx\n",
821 		(unsigned long)CPU_FTRS_POSSIBLE);
822 	pr_info("  always          = 0x%016lx\n",
823 		(unsigned long)CPU_FTRS_ALWAYS);
824 	pr_info("cpu_user_features = 0x%08x 0x%08x\n",
825 		cur_cpu_spec->cpu_user_features,
826 		cur_cpu_spec->cpu_user_features2);
827 	pr_info("mmu_features      = 0x%08x\n", cur_cpu_spec->mmu_features);
828 #ifdef CONFIG_PPC64
829 	pr_info("firmware_features = 0x%016lx\n", powerpc_firmware_features);
830 #ifdef CONFIG_PPC_BOOK3S
831 	pr_info("vmalloc start     = 0x%lx\n", KERN_VIRT_START);
832 	pr_info("IO start          = 0x%lx\n", KERN_IO_START);
833 	pr_info("vmemmap start     = 0x%lx\n", (unsigned long)vmemmap);
834 #endif
835 #endif
836 
837 	if (!early_radix_enabled())
838 		print_system_hash_info();
839 
840 	if (PHYSICAL_START > 0)
841 		pr_info("physical_start    = 0x%llx\n",
842 		       (unsigned long long)PHYSICAL_START);
843 	pr_info("-----------------------------------------------------\n");
844 }
845 
846 #ifdef CONFIG_SMP
847 static void __init smp_setup_pacas(void)
848 {
849 	int cpu;
850 
851 	for_each_possible_cpu(cpu) {
852 		if (cpu == smp_processor_id())
853 			continue;
854 		allocate_paca(cpu);
855 		set_hard_smp_processor_id(cpu, cpu_to_phys_id[cpu]);
856 	}
857 
858 	memblock_free(cpu_to_phys_id, nr_cpu_ids * sizeof(u32));
859 	cpu_to_phys_id = NULL;
860 }
861 #endif
862 
863 /*
864  * Called into from start_kernel this initializes memblock, which is used
865  * to manage page allocation until mem_init is called.
866  */
867 void __init setup_arch(char **cmdline_p)
868 {
869 	kasan_init();
870 
871 	*cmdline_p = boot_command_line;
872 
873 	/* Set a half-reasonable default so udelay does something sensible */
874 	loops_per_jiffy = 500000000 / HZ;
875 
876 	/* Unflatten the device-tree passed by prom_init or kexec */
877 	unflatten_device_tree();
878 
879 	/*
880 	 * Initialize cache line/block info from device-tree (on ppc64) or
881 	 * just cputable (on ppc32).
882 	 */
883 	initialize_cache_info();
884 
885 	/* Initialize RTAS if available. */
886 	rtas_initialize();
887 
888 	/* Check if we have an initrd provided via the device-tree. */
889 	check_for_initrd();
890 
891 	/* Probe the machine type, establish ppc_md. */
892 	probe_machine();
893 
894 	/* Setup panic notifier if requested by the platform. */
895 	setup_panic();
896 
897 	/*
898 	 * Configure ppc_md.power_save (ppc32 only, 64-bit machines do
899 	 * it from their respective probe() function.
900 	 */
901 	setup_power_save();
902 
903 	/* Discover standard serial ports. */
904 	find_legacy_serial_ports();
905 
906 	/* Register early console with the printk subsystem. */
907 	register_early_udbg_console();
908 
909 	/* Setup the various CPU maps based on the device-tree. */
910 	smp_setup_cpu_maps();
911 
912 	/* Initialize xmon. */
913 	xmon_setup();
914 
915 	/* Check the SMT related command line arguments (ppc64). */
916 	check_smt_enabled();
917 
918 	/* Parse memory topology */
919 	mem_topology_setup();
920 
921 	/*
922 	 * Release secondary cpus out of their spinloops at 0x60 now that
923 	 * we can map physical -> logical CPU ids.
924 	 *
925 	 * Freescale Book3e parts spin in a loop provided by firmware,
926 	 * so smp_release_cpus() does nothing for them.
927 	 */
928 #ifdef CONFIG_SMP
929 	smp_setup_pacas();
930 
931 	/* On BookE, setup per-core TLB data structures. */
932 	setup_tlb_core_data();
933 #endif
934 
935 	/* Print various info about the machine that has been gathered so far. */
936 	print_system_info();
937 
938 	klp_init_thread_info(&init_task);
939 
940 	setup_initial_init_mm(_stext, _etext, _edata, _end);
941 
942 	mm_iommu_init(&init_mm);
943 	irqstack_early_init();
944 	exc_lvl_early_init();
945 	emergency_stack_init();
946 
947 	mce_init();
948 	smp_release_cpus();
949 
950 	initmem_init();
951 
952 	/*
953 	 * Reserve large chunks of memory for use by CMA for KVM and hugetlb. These must
954 	 * be called after initmem_init(), so that pageblock_order is initialised.
955 	 */
956 	kvm_cma_reserve();
957 	gigantic_hugetlb_cma_reserve();
958 
959 	early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT);
960 
961 	if (ppc_md.setup_arch)
962 		ppc_md.setup_arch();
963 
964 	setup_barrier_nospec();
965 	setup_spectre_v2();
966 
967 	paging_init();
968 
969 	/* Initialize the MMU context management stuff. */
970 	mmu_context_init();
971 
972 	/* Interrupt code needs to be 64K-aligned. */
973 	if (IS_ENABLED(CONFIG_PPC64) && (unsigned long)_stext & 0xffff)
974 		panic("Kernelbase not 64K-aligned (0x%lx)!\n",
975 		      (unsigned long)_stext);
976 }
977