xref: /openbmc/linux/arch/powerpc/kernel/setup_64.c (revision 852a53a0)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  * Common boot and setup code.
5  *
6  * Copyright (C) 2001 PPC64 Team, IBM Corp
7  */
8 
9 #include <linux/export.h>
10 #include <linux/string.h>
11 #include <linux/sched.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/reboot.h>
15 #include <linux/delay.h>
16 #include <linux/initrd.h>
17 #include <linux/seq_file.h>
18 #include <linux/ioport.h>
19 #include <linux/console.h>
20 #include <linux/utsname.h>
21 #include <linux/tty.h>
22 #include <linux/root_dev.h>
23 #include <linux/notifier.h>
24 #include <linux/cpu.h>
25 #include <linux/unistd.h>
26 #include <linux/serial.h>
27 #include <linux/serial_8250.h>
28 #include <linux/memblock.h>
29 #include <linux/pci.h>
30 #include <linux/lockdep.h>
31 #include <linux/memory.h>
32 #include <linux/nmi.h>
33 #include <linux/pgtable.h>
34 
35 #include <asm/debugfs.h>
36 #include <asm/io.h>
37 #include <asm/kdump.h>
38 #include <asm/prom.h>
39 #include <asm/processor.h>
40 #include <asm/smp.h>
41 #include <asm/elf.h>
42 #include <asm/machdep.h>
43 #include <asm/paca.h>
44 #include <asm/time.h>
45 #include <asm/cputable.h>
46 #include <asm/dt_cpu_ftrs.h>
47 #include <asm/sections.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/firmware.h>
58 #include <asm/xmon.h>
59 #include <asm/udbg.h>
60 #include <asm/kexec.h>
61 #include <asm/code-patching.h>
62 #include <asm/livepatch.h>
63 #include <asm/opal.h>
64 #include <asm/cputhreads.h>
65 #include <asm/hw_irq.h>
66 #include <asm/feature-fixups.h>
67 #include <asm/kup.h>
68 #include <asm/early_ioremap.h>
69 
70 #include "setup.h"
71 
72 int spinning_secondaries;
73 u64 ppc64_pft_size;
74 
75 struct ppc64_caches ppc64_caches = {
76 	.l1d = {
77 		.block_size = 0x40,
78 		.log_block_size = 6,
79 	},
80 	.l1i = {
81 		.block_size = 0x40,
82 		.log_block_size = 6
83 	},
84 };
85 EXPORT_SYMBOL_GPL(ppc64_caches);
86 
87 #if defined(CONFIG_PPC_BOOK3E) && defined(CONFIG_SMP)
88 void __init setup_tlb_core_data(void)
89 {
90 	int cpu;
91 
92 	BUILD_BUG_ON(offsetof(struct tlb_core_data, lock) != 0);
93 
94 	for_each_possible_cpu(cpu) {
95 		int first = cpu_first_thread_sibling(cpu);
96 
97 		/*
98 		 * If we boot via kdump on a non-primary thread,
99 		 * make sure we point at the thread that actually
100 		 * set up this TLB.
101 		 */
102 		if (cpu_first_thread_sibling(boot_cpuid) == first)
103 			first = boot_cpuid;
104 
105 		paca_ptrs[cpu]->tcd_ptr = &paca_ptrs[first]->tcd;
106 
107 		/*
108 		 * If we have threads, we need either tlbsrx.
109 		 * or e6500 tablewalk mode, or else TLB handlers
110 		 * will be racy and could produce duplicate entries.
111 		 * Should we panic instead?
112 		 */
113 		WARN_ONCE(smt_enabled_at_boot >= 2 &&
114 			  !mmu_has_feature(MMU_FTR_USE_TLBRSRV) &&
115 			  book3e_htw_mode != PPC_HTW_E6500,
116 			  "%s: unsupported MMU configuration\n", __func__);
117 	}
118 }
119 #endif
120 
121 #ifdef CONFIG_SMP
122 
123 static char *smt_enabled_cmdline;
124 
125 /* Look for ibm,smt-enabled OF option */
126 void __init check_smt_enabled(void)
127 {
128 	struct device_node *dn;
129 	const char *smt_option;
130 
131 	/* Default to enabling all threads */
132 	smt_enabled_at_boot = threads_per_core;
133 
134 	/* Allow the command line to overrule the OF option */
135 	if (smt_enabled_cmdline) {
136 		if (!strcmp(smt_enabled_cmdline, "on"))
137 			smt_enabled_at_boot = threads_per_core;
138 		else if (!strcmp(smt_enabled_cmdline, "off"))
139 			smt_enabled_at_boot = 0;
140 		else {
141 			int smt;
142 			int rc;
143 
144 			rc = kstrtoint(smt_enabled_cmdline, 10, &smt);
145 			if (!rc)
146 				smt_enabled_at_boot =
147 					min(threads_per_core, smt);
148 		}
149 	} else {
150 		dn = of_find_node_by_path("/options");
151 		if (dn) {
152 			smt_option = of_get_property(dn, "ibm,smt-enabled",
153 						     NULL);
154 
155 			if (smt_option) {
156 				if (!strcmp(smt_option, "on"))
157 					smt_enabled_at_boot = threads_per_core;
158 				else if (!strcmp(smt_option, "off"))
159 					smt_enabled_at_boot = 0;
160 			}
161 
162 			of_node_put(dn);
163 		}
164 	}
165 }
166 
167 /* Look for smt-enabled= cmdline option */
168 static int __init early_smt_enabled(char *p)
169 {
170 	smt_enabled_cmdline = p;
171 	return 0;
172 }
173 early_param("smt-enabled", early_smt_enabled);
174 
175 #endif /* CONFIG_SMP */
176 
177 /** Fix up paca fields required for the boot cpu */
178 static void __init fixup_boot_paca(void)
179 {
180 	/* The boot cpu is started */
181 	get_paca()->cpu_start = 1;
182 	/* Allow percpu accesses to work until we setup percpu data */
183 	get_paca()->data_offset = 0;
184 	/* Mark interrupts disabled in PACA */
185 	irq_soft_mask_set(IRQS_DISABLED);
186 }
187 
188 static void __init configure_exceptions(void)
189 {
190 	/*
191 	 * Setup the trampolines from the lowmem exception vectors
192 	 * to the kdump kernel when not using a relocatable kernel.
193 	 */
194 	setup_kdump_trampoline();
195 
196 	/* Under a PAPR hypervisor, we need hypercalls */
197 	if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
198 		/* Enable AIL if possible */
199 		if (!pseries_enable_reloc_on_exc()) {
200 			init_task.thread.fscr &= ~FSCR_SCV;
201 			cur_cpu_spec->cpu_user_features2 &= ~PPC_FEATURE2_SCV;
202 		}
203 
204 		/*
205 		 * Tell the hypervisor that we want our exceptions to
206 		 * be taken in little endian mode.
207 		 *
208 		 * We don't call this for big endian as our calling convention
209 		 * makes us always enter in BE, and the call may fail under
210 		 * some circumstances with kdump.
211 		 */
212 #ifdef __LITTLE_ENDIAN__
213 		pseries_little_endian_exceptions();
214 #endif
215 	} else {
216 		/* Set endian mode using OPAL */
217 		if (firmware_has_feature(FW_FEATURE_OPAL))
218 			opal_configure_cores();
219 
220 		/* AIL on native is done in cpu_ready_for_interrupts() */
221 	}
222 }
223 
224 static void cpu_ready_for_interrupts(void)
225 {
226 	/*
227 	 * Enable AIL if supported, and we are in hypervisor mode. This
228 	 * is called once for every processor.
229 	 *
230 	 * If we are not in hypervisor mode the job is done once for
231 	 * the whole partition in configure_exceptions().
232 	 */
233 	if (cpu_has_feature(CPU_FTR_HVMODE) &&
234 	    cpu_has_feature(CPU_FTR_ARCH_207S)) {
235 		unsigned long lpcr = mfspr(SPRN_LPCR);
236 		mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
237 	}
238 
239 	/*
240 	 * Set HFSCR:TM based on CPU features:
241 	 * In the special case of TM no suspend (P9N DD2.1), Linux is
242 	 * told TM is off via the dt-ftrs but told to (partially) use
243 	 * it via OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED. So HFSCR[TM]
244 	 * will be off from dt-ftrs but we need to turn it on for the
245 	 * no suspend case.
246 	 */
247 	if (cpu_has_feature(CPU_FTR_HVMODE)) {
248 		if (cpu_has_feature(CPU_FTR_TM_COMP))
249 			mtspr(SPRN_HFSCR, mfspr(SPRN_HFSCR) | HFSCR_TM);
250 		else
251 			mtspr(SPRN_HFSCR, mfspr(SPRN_HFSCR) & ~HFSCR_TM);
252 	}
253 
254 	/* Set IR and DR in PACA MSR */
255 	get_paca()->kernel_msr = MSR_KERNEL;
256 }
257 
258 unsigned long spr_default_dscr = 0;
259 
260 void __init record_spr_defaults(void)
261 {
262 	if (early_cpu_has_feature(CPU_FTR_DSCR))
263 		spr_default_dscr = mfspr(SPRN_DSCR);
264 }
265 
266 /*
267  * Early initialization entry point. This is called by head.S
268  * with MMU translation disabled. We rely on the "feature" of
269  * the CPU that ignores the top 2 bits of the address in real
270  * mode so we can access kernel globals normally provided we
271  * only toy with things in the RMO region. From here, we do
272  * some early parsing of the device-tree to setup out MEMBLOCK
273  * data structures, and allocate & initialize the hash table
274  * and segment tables so we can start running with translation
275  * enabled.
276  *
277  * It is this function which will call the probe() callback of
278  * the various platform types and copy the matching one to the
279  * global ppc_md structure. Your platform can eventually do
280  * some very early initializations from the probe() routine, but
281  * this is not recommended, be very careful as, for example, the
282  * device-tree is not accessible via normal means at this point.
283  */
284 
285 void __init __nostackprotector early_setup(unsigned long dt_ptr)
286 {
287 	static __initdata struct paca_struct boot_paca;
288 
289 	/* -------- printk is _NOT_ safe to use here ! ------- */
290 
291 	/*
292 	 * Assume we're on cpu 0 for now.
293 	 *
294 	 * We need to load a PACA very early for a few reasons.
295 	 *
296 	 * The stack protector canary is stored in the paca, so as soon as we
297 	 * call any stack protected code we need r13 pointing somewhere valid.
298 	 *
299 	 * If we are using kcov it will call in_task() in its instrumentation,
300 	 * which relies on the current task from the PACA.
301 	 *
302 	 * dt_cpu_ftrs_init() calls into generic OF/fdt code, as well as
303 	 * printk(), which can trigger both stack protector and kcov.
304 	 *
305 	 * percpu variables and spin locks also use the paca.
306 	 *
307 	 * So set up a temporary paca. It will be replaced below once we know
308 	 * what CPU we are on.
309 	 */
310 	initialise_paca(&boot_paca, 0);
311 	setup_paca(&boot_paca);
312 	fixup_boot_paca();
313 
314 	/* -------- printk is now safe to use ------- */
315 
316 	/* Try new device tree based feature discovery ... */
317 	if (!dt_cpu_ftrs_init(__va(dt_ptr)))
318 		/* Otherwise use the old style CPU table */
319 		identify_cpu(0, mfspr(SPRN_PVR));
320 
321 	/* Enable early debugging if any specified (see udbg.h) */
322 	udbg_early_init();
323 
324 	udbg_printf(" -> %s(), dt_ptr: 0x%lx\n", __func__, dt_ptr);
325 
326 	/*
327 	 * Do early initialization using the flattened device
328 	 * tree, such as retrieving the physical memory map or
329 	 * calculating/retrieving the hash table size.
330 	 */
331 	early_init_devtree(__va(dt_ptr));
332 
333 	/* Now we know the logical id of our boot cpu, setup the paca. */
334 	if (boot_cpuid != 0) {
335 		/* Poison paca_ptrs[0] again if it's not the boot cpu */
336 		memset(&paca_ptrs[0], 0x88, sizeof(paca_ptrs[0]));
337 	}
338 	setup_paca(paca_ptrs[boot_cpuid]);
339 	fixup_boot_paca();
340 
341 	/*
342 	 * Configure exception handlers. This include setting up trampolines
343 	 * if needed, setting exception endian mode, etc...
344 	 */
345 	configure_exceptions();
346 
347 	/*
348 	 * Configure Kernel Userspace Protection. This needs to happen before
349 	 * feature fixups for platforms that implement this using features.
350 	 */
351 	setup_kup();
352 
353 	/* Apply all the dynamic patching */
354 	apply_feature_fixups();
355 	setup_feature_keys();
356 
357 	early_ioremap_setup();
358 
359 	/* Initialize the hash table or TLB handling */
360 	early_init_mmu();
361 
362 	/*
363 	 * After firmware and early platform setup code has set things up,
364 	 * we note the SPR values for configurable control/performance
365 	 * registers, and use those as initial defaults.
366 	 */
367 	record_spr_defaults();
368 
369 	/*
370 	 * At this point, we can let interrupts switch to virtual mode
371 	 * (the MMU has been setup), so adjust the MSR in the PACA to
372 	 * have IR and DR set and enable AIL if it exists
373 	 */
374 	cpu_ready_for_interrupts();
375 
376 	/*
377 	 * We enable ftrace here, but since we only support DYNAMIC_FTRACE, it
378 	 * will only actually get enabled on the boot cpu much later once
379 	 * ftrace itself has been initialized.
380 	 */
381 	this_cpu_enable_ftrace();
382 
383 	udbg_printf(" <- %s()\n", __func__);
384 
385 #ifdef CONFIG_PPC_EARLY_DEBUG_BOOTX
386 	/*
387 	 * This needs to be done *last* (after the above udbg_printf() even)
388 	 *
389 	 * Right after we return from this function, we turn on the MMU
390 	 * which means the real-mode access trick that btext does will
391 	 * no longer work, it needs to switch to using a real MMU
392 	 * mapping. This call will ensure that it does
393 	 */
394 	btext_map();
395 #endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */
396 }
397 
398 #ifdef CONFIG_SMP
399 void early_setup_secondary(void)
400 {
401 	/* Mark interrupts disabled in PACA */
402 	irq_soft_mask_set(IRQS_DISABLED);
403 
404 	/* Initialize the hash table or TLB handling */
405 	early_init_mmu_secondary();
406 
407 	/* Perform any KUP setup that is per-cpu */
408 	setup_kup();
409 
410 	/*
411 	 * At this point, we can let interrupts switch to virtual mode
412 	 * (the MMU has been setup), so adjust the MSR in the PACA to
413 	 * have IR and DR set.
414 	 */
415 	cpu_ready_for_interrupts();
416 }
417 
418 #endif /* CONFIG_SMP */
419 
420 void panic_smp_self_stop(void)
421 {
422 	hard_irq_disable();
423 	spin_begin();
424 	while (1)
425 		spin_cpu_relax();
426 }
427 
428 #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC_CORE)
429 static bool use_spinloop(void)
430 {
431 	if (IS_ENABLED(CONFIG_PPC_BOOK3S)) {
432 		/*
433 		 * See comments in head_64.S -- not all platforms insert
434 		 * secondaries at __secondary_hold and wait at the spin
435 		 * loop.
436 		 */
437 		if (firmware_has_feature(FW_FEATURE_OPAL))
438 			return false;
439 		return true;
440 	}
441 
442 	/*
443 	 * When book3e boots from kexec, the ePAPR spin table does
444 	 * not get used.
445 	 */
446 	return of_property_read_bool(of_chosen, "linux,booted-from-kexec");
447 }
448 
449 void smp_release_cpus(void)
450 {
451 	unsigned long *ptr;
452 	int i;
453 
454 	if (!use_spinloop())
455 		return;
456 
457 	/* All secondary cpus are spinning on a common spinloop, release them
458 	 * all now so they can start to spin on their individual paca
459 	 * spinloops. For non SMP kernels, the secondary cpus never get out
460 	 * of the common spinloop.
461 	 */
462 
463 	ptr  = (unsigned long *)((unsigned long)&__secondary_hold_spinloop
464 			- PHYSICAL_START);
465 	*ptr = ppc_function_entry(generic_secondary_smp_init);
466 
467 	/* And wait a bit for them to catch up */
468 	for (i = 0; i < 100000; i++) {
469 		mb();
470 		HMT_low();
471 		if (spinning_secondaries == 0)
472 			break;
473 		udelay(1);
474 	}
475 	pr_debug("spinning_secondaries = %d\n", spinning_secondaries);
476 }
477 #endif /* CONFIG_SMP || CONFIG_KEXEC_CORE */
478 
479 /*
480  * Initialize some remaining members of the ppc64_caches and systemcfg
481  * structures
482  * (at least until we get rid of them completely). This is mostly some
483  * cache informations about the CPU that will be used by cache flush
484  * routines and/or provided to userland
485  */
486 
487 static void init_cache_info(struct ppc_cache_info *info, u32 size, u32 lsize,
488 			    u32 bsize, u32 sets)
489 {
490 	info->size = size;
491 	info->sets = sets;
492 	info->line_size = lsize;
493 	info->block_size = bsize;
494 	info->log_block_size = __ilog2(bsize);
495 	if (bsize)
496 		info->blocks_per_page = PAGE_SIZE / bsize;
497 	else
498 		info->blocks_per_page = 0;
499 
500 	if (sets == 0)
501 		info->assoc = 0xffff;
502 	else
503 		info->assoc = size / (sets * lsize);
504 }
505 
506 static bool __init parse_cache_info(struct device_node *np,
507 				    bool icache,
508 				    struct ppc_cache_info *info)
509 {
510 	static const char *ipropnames[] __initdata = {
511 		"i-cache-size",
512 		"i-cache-sets",
513 		"i-cache-block-size",
514 		"i-cache-line-size",
515 	};
516 	static const char *dpropnames[] __initdata = {
517 		"d-cache-size",
518 		"d-cache-sets",
519 		"d-cache-block-size",
520 		"d-cache-line-size",
521 	};
522 	const char **propnames = icache ? ipropnames : dpropnames;
523 	const __be32 *sizep, *lsizep, *bsizep, *setsp;
524 	u32 size, lsize, bsize, sets;
525 	bool success = true;
526 
527 	size = 0;
528 	sets = -1u;
529 	lsize = bsize = cur_cpu_spec->dcache_bsize;
530 	sizep = of_get_property(np, propnames[0], NULL);
531 	if (sizep != NULL)
532 		size = be32_to_cpu(*sizep);
533 	setsp = of_get_property(np, propnames[1], NULL);
534 	if (setsp != NULL)
535 		sets = be32_to_cpu(*setsp);
536 	bsizep = of_get_property(np, propnames[2], NULL);
537 	lsizep = of_get_property(np, propnames[3], NULL);
538 	if (bsizep == NULL)
539 		bsizep = lsizep;
540 	if (lsizep == NULL)
541 		lsizep = bsizep;
542 	if (lsizep != NULL)
543 		lsize = be32_to_cpu(*lsizep);
544 	if (bsizep != NULL)
545 		bsize = be32_to_cpu(*bsizep);
546 	if (sizep == NULL || bsizep == NULL || lsizep == NULL)
547 		success = false;
548 
549 	/*
550 	 * OF is weird .. it represents fully associative caches
551 	 * as "1 way" which doesn't make much sense and doesn't
552 	 * leave room for direct mapped. We'll assume that 0
553 	 * in OF means direct mapped for that reason.
554 	 */
555 	if (sets == 1)
556 		sets = 0;
557 	else if (sets == 0)
558 		sets = 1;
559 
560 	init_cache_info(info, size, lsize, bsize, sets);
561 
562 	return success;
563 }
564 
565 void __init initialize_cache_info(void)
566 {
567 	struct device_node *cpu = NULL, *l2, *l3 = NULL;
568 	u32 pvr;
569 
570 	/*
571 	 * All shipping POWER8 machines have a firmware bug that
572 	 * puts incorrect information in the device-tree. This will
573 	 * be (hopefully) fixed for future chips but for now hard
574 	 * code the values if we are running on one of these
575 	 */
576 	pvr = PVR_VER(mfspr(SPRN_PVR));
577 	if (pvr == PVR_POWER8 || pvr == PVR_POWER8E ||
578 	    pvr == PVR_POWER8NVL) {
579 						/* size    lsize   blk  sets */
580 		init_cache_info(&ppc64_caches.l1i, 0x8000,   128,  128, 32);
581 		init_cache_info(&ppc64_caches.l1d, 0x10000,  128,  128, 64);
582 		init_cache_info(&ppc64_caches.l2,  0x80000,  128,  0,   512);
583 		init_cache_info(&ppc64_caches.l3,  0x800000, 128,  0,   8192);
584 	} else
585 		cpu = of_find_node_by_type(NULL, "cpu");
586 
587 	/*
588 	 * We're assuming *all* of the CPUs have the same
589 	 * d-cache and i-cache sizes... -Peter
590 	 */
591 	if (cpu) {
592 		if (!parse_cache_info(cpu, false, &ppc64_caches.l1d))
593 			pr_warn("Argh, can't find dcache properties !\n");
594 
595 		if (!parse_cache_info(cpu, true, &ppc64_caches.l1i))
596 			pr_warn("Argh, can't find icache properties !\n");
597 
598 		/*
599 		 * Try to find the L2 and L3 if any. Assume they are
600 		 * unified and use the D-side properties.
601 		 */
602 		l2 = of_find_next_cache_node(cpu);
603 		of_node_put(cpu);
604 		if (l2) {
605 			parse_cache_info(l2, false, &ppc64_caches.l2);
606 			l3 = of_find_next_cache_node(l2);
607 			of_node_put(l2);
608 		}
609 		if (l3) {
610 			parse_cache_info(l3, false, &ppc64_caches.l3);
611 			of_node_put(l3);
612 		}
613 	}
614 
615 	/* For use by binfmt_elf */
616 	dcache_bsize = ppc64_caches.l1d.block_size;
617 	icache_bsize = ppc64_caches.l1i.block_size;
618 
619 	cur_cpu_spec->dcache_bsize = dcache_bsize;
620 	cur_cpu_spec->icache_bsize = icache_bsize;
621 }
622 
623 /*
624  * This returns the limit below which memory accesses to the linear
625  * mapping are guarnateed not to cause an architectural exception (e.g.,
626  * TLB or SLB miss fault).
627  *
628  * This is used to allocate PACAs and various interrupt stacks that
629  * that are accessed early in interrupt handlers that must not cause
630  * re-entrant interrupts.
631  */
632 __init u64 ppc64_bolted_size(void)
633 {
634 #ifdef CONFIG_PPC_BOOK3E
635 	/* Freescale BookE bolts the entire linear mapping */
636 	/* XXX: BookE ppc64_rma_limit setup seems to disagree? */
637 	if (early_mmu_has_feature(MMU_FTR_TYPE_FSL_E))
638 		return linear_map_top;
639 	/* Other BookE, we assume the first GB is bolted */
640 	return 1ul << 30;
641 #else
642 	/* BookS radix, does not take faults on linear mapping */
643 	if (early_radix_enabled())
644 		return ULONG_MAX;
645 
646 	/* BookS hash, the first segment is bolted */
647 	if (early_mmu_has_feature(MMU_FTR_1T_SEGMENT))
648 		return 1UL << SID_SHIFT_1T;
649 	return 1UL << SID_SHIFT;
650 #endif
651 }
652 
653 static void *__init alloc_stack(unsigned long limit, int cpu)
654 {
655 	void *ptr;
656 
657 	BUILD_BUG_ON(STACK_INT_FRAME_SIZE % 16);
658 
659 	ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_ALIGN,
660 				     MEMBLOCK_LOW_LIMIT, limit,
661 				     early_cpu_to_node(cpu));
662 	if (!ptr)
663 		panic("cannot allocate stacks");
664 
665 	return ptr;
666 }
667 
668 void __init irqstack_early_init(void)
669 {
670 	u64 limit = ppc64_bolted_size();
671 	unsigned int i;
672 
673 	/*
674 	 * Interrupt stacks must be in the first segment since we
675 	 * cannot afford to take SLB misses on them. They are not
676 	 * accessed in realmode.
677 	 */
678 	for_each_possible_cpu(i) {
679 		softirq_ctx[i] = alloc_stack(limit, i);
680 		hardirq_ctx[i] = alloc_stack(limit, i);
681 	}
682 }
683 
684 #ifdef CONFIG_PPC_BOOK3E
685 void __init exc_lvl_early_init(void)
686 {
687 	unsigned int i;
688 
689 	for_each_possible_cpu(i) {
690 		void *sp;
691 
692 		sp = alloc_stack(ULONG_MAX, i);
693 		critirq_ctx[i] = sp;
694 		paca_ptrs[i]->crit_kstack = sp + THREAD_SIZE;
695 
696 		sp = alloc_stack(ULONG_MAX, i);
697 		dbgirq_ctx[i] = sp;
698 		paca_ptrs[i]->dbg_kstack = sp + THREAD_SIZE;
699 
700 		sp = alloc_stack(ULONG_MAX, i);
701 		mcheckirq_ctx[i] = sp;
702 		paca_ptrs[i]->mc_kstack = sp + THREAD_SIZE;
703 	}
704 
705 	if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
706 		patch_exception(0x040, exc_debug_debug_book3e);
707 }
708 #endif
709 
710 /*
711  * Stack space used when we detect a bad kernel stack pointer, and
712  * early in SMP boots before relocation is enabled. Exclusive emergency
713  * stack for machine checks.
714  */
715 void __init emergency_stack_init(void)
716 {
717 	u64 limit, mce_limit;
718 	unsigned int i;
719 
720 	/*
721 	 * Emergency stacks must be under 256MB, we cannot afford to take
722 	 * SLB misses on them. The ABI also requires them to be 128-byte
723 	 * aligned.
724 	 *
725 	 * Since we use these as temporary stacks during secondary CPU
726 	 * bringup, machine check, system reset, and HMI, we need to get
727 	 * at them in real mode. This means they must also be within the RMO
728 	 * region.
729 	 *
730 	 * The IRQ stacks allocated elsewhere in this file are zeroed and
731 	 * initialized in kernel/irq.c. These are initialized here in order
732 	 * to have emergency stacks available as early as possible.
733 	 */
734 	limit = mce_limit = min(ppc64_bolted_size(), ppc64_rma_size);
735 
736 	/*
737 	 * Machine check on pseries calls rtas, but can't use the static
738 	 * rtas_args due to a machine check hitting while the lock is held.
739 	 * rtas args have to be under 4GB, so the machine check stack is
740 	 * limited to 4GB so args can be put on stack.
741 	 */
742 	if (firmware_has_feature(FW_FEATURE_LPAR) && mce_limit > SZ_4G)
743 		mce_limit = SZ_4G;
744 
745 	for_each_possible_cpu(i) {
746 		paca_ptrs[i]->emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
747 
748 #ifdef CONFIG_PPC_BOOK3S_64
749 		/* emergency stack for NMI exception handling. */
750 		paca_ptrs[i]->nmi_emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
751 
752 		/* emergency stack for machine check exception handling. */
753 		paca_ptrs[i]->mc_emergency_sp = alloc_stack(mce_limit, i) + THREAD_SIZE;
754 #endif
755 	}
756 }
757 
758 #ifdef CONFIG_SMP
759 #define PCPU_DYN_SIZE		()
760 
761 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
762 {
763 	return memblock_alloc_try_nid(size, align, __pa(MAX_DMA_ADDRESS),
764 				      MEMBLOCK_ALLOC_ACCESSIBLE,
765 				      early_cpu_to_node(cpu));
766 
767 }
768 
769 static void __init pcpu_fc_free(void *ptr, size_t size)
770 {
771 	memblock_free(__pa(ptr), size);
772 }
773 
774 static int pcpu_cpu_distance(unsigned int from, unsigned int to)
775 {
776 	if (early_cpu_to_node(from) == early_cpu_to_node(to))
777 		return LOCAL_DISTANCE;
778 	else
779 		return REMOTE_DISTANCE;
780 }
781 
782 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
783 EXPORT_SYMBOL(__per_cpu_offset);
784 
785 void __init setup_per_cpu_areas(void)
786 {
787 	const size_t dyn_size = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
788 	size_t atom_size;
789 	unsigned long delta;
790 	unsigned int cpu;
791 	int rc;
792 
793 	/*
794 	 * Linear mapping is one of 4K, 1M and 16M.  For 4K, no need
795 	 * to group units.  For larger mappings, use 1M atom which
796 	 * should be large enough to contain a number of units.
797 	 */
798 	if (mmu_linear_psize == MMU_PAGE_4K)
799 		atom_size = PAGE_SIZE;
800 	else
801 		atom_size = 1 << 20;
802 
803 	rc = pcpu_embed_first_chunk(0, dyn_size, atom_size, pcpu_cpu_distance,
804 				    pcpu_fc_alloc, pcpu_fc_free);
805 	if (rc < 0)
806 		panic("cannot initialize percpu area (err=%d)", rc);
807 
808 	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
809 	for_each_possible_cpu(cpu) {
810                 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
811 		paca_ptrs[cpu]->data_offset = __per_cpu_offset[cpu];
812 	}
813 }
814 #endif
815 
816 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
817 unsigned long memory_block_size_bytes(void)
818 {
819 	if (ppc_md.memory_block_size)
820 		return ppc_md.memory_block_size();
821 
822 	return MIN_MEMORY_BLOCK_SIZE;
823 }
824 #endif
825 
826 #if defined(CONFIG_PPC_INDIRECT_PIO) || defined(CONFIG_PPC_INDIRECT_MMIO)
827 struct ppc_pci_io ppc_pci_io;
828 EXPORT_SYMBOL(ppc_pci_io);
829 #endif
830 
831 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
832 u64 hw_nmi_get_sample_period(int watchdog_thresh)
833 {
834 	return ppc_proc_freq * watchdog_thresh;
835 }
836 #endif
837 
838 /*
839  * The perf based hardlockup detector breaks PMU event based branches, so
840  * disable it by default. Book3S has a soft-nmi hardlockup detector based
841  * on the decrementer interrupt, so it does not suffer from this problem.
842  *
843  * It is likely to get false positives in VM guests, so disable it there
844  * by default too.
845  */
846 static int __init disable_hardlockup_detector(void)
847 {
848 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
849 	hardlockup_detector_disable();
850 #else
851 	if (firmware_has_feature(FW_FEATURE_LPAR))
852 		hardlockup_detector_disable();
853 #endif
854 
855 	return 0;
856 }
857 early_initcall(disable_hardlockup_detector);
858 
859 #ifdef CONFIG_PPC_BOOK3S_64
860 static enum l1d_flush_type enabled_flush_types;
861 static void *l1d_flush_fallback_area;
862 static bool no_rfi_flush;
863 bool rfi_flush;
864 
865 static int __init handle_no_rfi_flush(char *p)
866 {
867 	pr_info("rfi-flush: disabled on command line.");
868 	no_rfi_flush = true;
869 	return 0;
870 }
871 early_param("no_rfi_flush", handle_no_rfi_flush);
872 
873 /*
874  * The RFI flush is not KPTI, but because users will see doco that says to use
875  * nopti we hijack that option here to also disable the RFI flush.
876  */
877 static int __init handle_no_pti(char *p)
878 {
879 	pr_info("rfi-flush: disabling due to 'nopti' on command line.\n");
880 	handle_no_rfi_flush(NULL);
881 	return 0;
882 }
883 early_param("nopti", handle_no_pti);
884 
885 static void do_nothing(void *unused)
886 {
887 	/*
888 	 * We don't need to do the flush explicitly, just enter+exit kernel is
889 	 * sufficient, the RFI exit handlers will do the right thing.
890 	 */
891 }
892 
893 void rfi_flush_enable(bool enable)
894 {
895 	if (enable) {
896 		do_rfi_flush_fixups(enabled_flush_types);
897 		on_each_cpu(do_nothing, NULL, 1);
898 	} else
899 		do_rfi_flush_fixups(L1D_FLUSH_NONE);
900 
901 	rfi_flush = enable;
902 }
903 
904 static void __ref init_fallback_flush(void)
905 {
906 	u64 l1d_size, limit;
907 	int cpu;
908 
909 	/* Only allocate the fallback flush area once (at boot time). */
910 	if (l1d_flush_fallback_area)
911 		return;
912 
913 	l1d_size = ppc64_caches.l1d.size;
914 
915 	/*
916 	 * If there is no d-cache-size property in the device tree, l1d_size
917 	 * could be zero. That leads to the loop in the asm wrapping around to
918 	 * 2^64-1, and then walking off the end of the fallback area and
919 	 * eventually causing a page fault which is fatal. Just default to
920 	 * something vaguely sane.
921 	 */
922 	if (!l1d_size)
923 		l1d_size = (64 * 1024);
924 
925 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
926 
927 	/*
928 	 * Align to L1d size, and size it at 2x L1d size, to catch possible
929 	 * hardware prefetch runoff. We don't have a recipe for load patterns to
930 	 * reliably avoid the prefetcher.
931 	 */
932 	l1d_flush_fallback_area = memblock_alloc_try_nid(l1d_size * 2,
933 						l1d_size, MEMBLOCK_LOW_LIMIT,
934 						limit, NUMA_NO_NODE);
935 	if (!l1d_flush_fallback_area)
936 		panic("%s: Failed to allocate %llu bytes align=0x%llx max_addr=%pa\n",
937 		      __func__, l1d_size * 2, l1d_size, &limit);
938 
939 
940 	for_each_possible_cpu(cpu) {
941 		struct paca_struct *paca = paca_ptrs[cpu];
942 		paca->rfi_flush_fallback_area = l1d_flush_fallback_area;
943 		paca->l1d_flush_size = l1d_size;
944 	}
945 }
946 
947 void setup_rfi_flush(enum l1d_flush_type types, bool enable)
948 {
949 	if (types & L1D_FLUSH_FALLBACK) {
950 		pr_info("rfi-flush: fallback displacement flush available\n");
951 		init_fallback_flush();
952 	}
953 
954 	if (types & L1D_FLUSH_ORI)
955 		pr_info("rfi-flush: ori type flush available\n");
956 
957 	if (types & L1D_FLUSH_MTTRIG)
958 		pr_info("rfi-flush: mttrig type flush available\n");
959 
960 	enabled_flush_types = types;
961 
962 	if (!no_rfi_flush && !cpu_mitigations_off())
963 		rfi_flush_enable(enable);
964 }
965 
966 #ifdef CONFIG_DEBUG_FS
967 static int rfi_flush_set(void *data, u64 val)
968 {
969 	bool enable;
970 
971 	if (val == 1)
972 		enable = true;
973 	else if (val == 0)
974 		enable = false;
975 	else
976 		return -EINVAL;
977 
978 	/* Only do anything if we're changing state */
979 	if (enable != rfi_flush)
980 		rfi_flush_enable(enable);
981 
982 	return 0;
983 }
984 
985 static int rfi_flush_get(void *data, u64 *val)
986 {
987 	*val = rfi_flush ? 1 : 0;
988 	return 0;
989 }
990 
991 DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n");
992 
993 static __init int rfi_flush_debugfs_init(void)
994 {
995 	debugfs_create_file("rfi_flush", 0600, powerpc_debugfs_root, NULL, &fops_rfi_flush);
996 	return 0;
997 }
998 device_initcall(rfi_flush_debugfs_init);
999 #endif
1000 #endif /* CONFIG_PPC_BOOK3S_64 */
1001