1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PowerNV setup code.
4  *
5  * Copyright 2011 IBM Corp.
6  */
7 
8 #undef DEBUG
9 
10 #include <linux/cpu.h>
11 #include <linux/errno.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/tty.h>
15 #include <linux/reboot.h>
16 #include <linux/init.h>
17 #include <linux/console.h>
18 #include <linux/delay.h>
19 #include <linux/irq.h>
20 #include <linux/seq_file.h>
21 #include <linux/of.h>
22 #include <linux/of_fdt.h>
23 #include <linux/interrupt.h>
24 #include <linux/bug.h>
25 #include <linux/pci.h>
26 #include <linux/cpufreq.h>
27 #include <linux/memblock.h>
28 
29 #include <asm/machdep.h>
30 #include <asm/firmware.h>
31 #include <asm/xics.h>
32 #include <asm/xive.h>
33 #include <asm/opal.h>
34 #include <asm/kexec.h>
35 #include <asm/smp.h>
36 #include <asm/tm.h>
37 #include <asm/setup.h>
38 #include <asm/security_features.h>
39 
40 #include "powernv.h"
41 
42 
43 static bool fw_feature_is(const char *state, const char *name,
44 			  struct device_node *fw_features)
45 {
46 	struct device_node *np;
47 	bool rc = false;
48 
49 	np = of_get_child_by_name(fw_features, name);
50 	if (np) {
51 		rc = of_property_read_bool(np, state);
52 		of_node_put(np);
53 	}
54 
55 	return rc;
56 }
57 
58 static void init_fw_feat_flags(struct device_node *np)
59 {
60 	if (fw_feature_is("enabled", "inst-spec-barrier-ori31,31,0", np))
61 		security_ftr_set(SEC_FTR_SPEC_BAR_ORI31);
62 
63 	if (fw_feature_is("enabled", "fw-bcctrl-serialized", np))
64 		security_ftr_set(SEC_FTR_BCCTRL_SERIALISED);
65 
66 	if (fw_feature_is("enabled", "inst-l1d-flush-ori30,30,0", np))
67 		security_ftr_set(SEC_FTR_L1D_FLUSH_ORI30);
68 
69 	if (fw_feature_is("enabled", "inst-l1d-flush-trig2", np))
70 		security_ftr_set(SEC_FTR_L1D_FLUSH_TRIG2);
71 
72 	if (fw_feature_is("enabled", "fw-l1d-thread-split", np))
73 		security_ftr_set(SEC_FTR_L1D_THREAD_PRIV);
74 
75 	if (fw_feature_is("enabled", "fw-count-cache-disabled", np))
76 		security_ftr_set(SEC_FTR_COUNT_CACHE_DISABLED);
77 
78 	if (fw_feature_is("enabled", "fw-count-cache-flush-bcctr2,0,0", np))
79 		security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);
80 
81 	if (fw_feature_is("enabled", "needs-count-cache-flush-on-context-switch", np))
82 		security_ftr_set(SEC_FTR_FLUSH_COUNT_CACHE);
83 
84 	/*
85 	 * The features below are enabled by default, so we instead look to see
86 	 * if firmware has *disabled* them, and clear them if so.
87 	 */
88 	if (fw_feature_is("disabled", "speculation-policy-favor-security", np))
89 		security_ftr_clear(SEC_FTR_FAVOUR_SECURITY);
90 
91 	if (fw_feature_is("disabled", "needs-l1d-flush-msr-pr-0-to-1", np))
92 		security_ftr_clear(SEC_FTR_L1D_FLUSH_PR);
93 
94 	if (fw_feature_is("disabled", "needs-l1d-flush-msr-hv-1-to-0", np))
95 		security_ftr_clear(SEC_FTR_L1D_FLUSH_HV);
96 
97 	if (fw_feature_is("disabled", "needs-spec-barrier-for-bound-checks", np))
98 		security_ftr_clear(SEC_FTR_BNDS_CHK_SPEC_BAR);
99 }
100 
101 static void pnv_setup_security_mitigations(void)
102 {
103 	struct device_node *np, *fw_features;
104 	enum l1d_flush_type type;
105 	bool enable;
106 
107 	/* Default to fallback in case fw-features are not available */
108 	type = L1D_FLUSH_FALLBACK;
109 
110 	np = of_find_node_by_name(NULL, "ibm,opal");
111 	fw_features = of_get_child_by_name(np, "fw-features");
112 	of_node_put(np);
113 
114 	if (fw_features) {
115 		init_fw_feat_flags(fw_features);
116 		of_node_put(fw_features);
117 
118 		if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_TRIG2))
119 			type = L1D_FLUSH_MTTRIG;
120 
121 		if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_ORI30))
122 			type = L1D_FLUSH_ORI;
123 	}
124 
125 	/*
126 	 * If we are non-Power9 bare metal, we don't need to flush on kernel
127 	 * entry or after user access: they fix a P9 specific vulnerability.
128 	 */
129 	if (!pvr_version_is(PVR_POWER9)) {
130 		security_ftr_clear(SEC_FTR_L1D_FLUSH_ENTRY);
131 		security_ftr_clear(SEC_FTR_L1D_FLUSH_UACCESS);
132 	}
133 
134 	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && \
135 		 (security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR)   || \
136 		  security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV));
137 
138 	setup_rfi_flush(type, enable);
139 	setup_count_cache_flush();
140 
141 	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
142 		 security_ftr_enabled(SEC_FTR_L1D_FLUSH_ENTRY);
143 	setup_entry_flush(enable);
144 
145 	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
146 		 security_ftr_enabled(SEC_FTR_L1D_FLUSH_UACCESS);
147 	setup_uaccess_flush(enable);
148 
149 	setup_stf_barrier();
150 }
151 
152 static void __init pnv_check_guarded_cores(void)
153 {
154 	struct device_node *dn;
155 	int bad_count = 0;
156 
157 	for_each_node_by_type(dn, "cpu") {
158 		if (of_property_match_string(dn, "status", "bad") >= 0)
159 			bad_count++;
160 	}
161 
162 	if (bad_count) {
163 		printk("  _     _______________\n");
164 		pr_cont(" | |   /               \\\n");
165 		pr_cont(" | |   |    WARNING!   |\n");
166 		pr_cont(" | |   |               |\n");
167 		pr_cont(" | |   | It looks like |\n");
168 		pr_cont(" |_|   |  you have %*d |\n", 3, bad_count);
169 		pr_cont("  _    | guarded cores |\n");
170 		pr_cont(" (_)   \\_______________/\n");
171 	}
172 }
173 
174 static void __init pnv_setup_arch(void)
175 {
176 	set_arch_panic_timeout(10, ARCH_PANIC_TIMEOUT);
177 
178 	pnv_setup_security_mitigations();
179 
180 	/* Initialize SMP */
181 	pnv_smp_init();
182 
183 	/* Setup RTC and NVRAM callbacks */
184 	if (firmware_has_feature(FW_FEATURE_OPAL))
185 		opal_nvram_init();
186 
187 	/* Enable NAP mode */
188 	powersave_nap = 1;
189 
190 	pnv_check_guarded_cores();
191 
192 	/* XXX PMCS */
193 }
194 
195 static void __init pnv_init(void)
196 {
197 	/*
198 	 * Initialize the LPC bus now so that legacy serial
199 	 * ports can be found on it
200 	 */
201 	opal_lpc_init();
202 
203 #ifdef CONFIG_HVC_OPAL
204 	if (firmware_has_feature(FW_FEATURE_OPAL))
205 		hvc_opal_init_early();
206 	else
207 #endif
208 		add_preferred_console("hvc", 0, NULL);
209 
210 	if (!radix_enabled()) {
211 		size_t size = sizeof(struct slb_entry) * mmu_slb_size;
212 		int i;
213 
214 		/* Allocate per cpu area to save old slb contents during MCE */
215 		for_each_possible_cpu(i) {
216 			paca_ptrs[i]->mce_faulty_slbs =
217 					memblock_alloc_node(size,
218 						__alignof__(struct slb_entry),
219 						cpu_to_node(i));
220 		}
221 	}
222 }
223 
224 static void __init pnv_init_IRQ(void)
225 {
226 	/* Try using a XIVE if available, otherwise use a XICS */
227 	if (!xive_native_init())
228 		xics_init();
229 
230 	WARN_ON(!ppc_md.get_irq);
231 }
232 
233 static void pnv_show_cpuinfo(struct seq_file *m)
234 {
235 	struct device_node *root;
236 	const char *model = "";
237 
238 	root = of_find_node_by_path("/");
239 	if (root)
240 		model = of_get_property(root, "model", NULL);
241 	seq_printf(m, "machine\t\t: PowerNV %s\n", model);
242 	if (firmware_has_feature(FW_FEATURE_OPAL))
243 		seq_printf(m, "firmware\t: OPAL\n");
244 	else
245 		seq_printf(m, "firmware\t: BML\n");
246 	of_node_put(root);
247 	if (radix_enabled())
248 		seq_printf(m, "MMU\t\t: Radix\n");
249 	else
250 		seq_printf(m, "MMU\t\t: Hash\n");
251 }
252 
253 static void pnv_prepare_going_down(void)
254 {
255 	/*
256 	 * Disable all notifiers from OPAL, we can't
257 	 * service interrupts anymore anyway
258 	 */
259 	opal_event_shutdown();
260 
261 	/* Print flash update message if one is scheduled. */
262 	opal_flash_update_print_message();
263 
264 	smp_send_stop();
265 
266 	hard_irq_disable();
267 }
268 
269 static void  __noreturn pnv_restart(char *cmd)
270 {
271 	long rc;
272 
273 	pnv_prepare_going_down();
274 
275 	do {
276 		if (!cmd || !strlen(cmd))
277 			rc = opal_cec_reboot();
278 		else if (strcmp(cmd, "full") == 0)
279 			rc = opal_cec_reboot2(OPAL_REBOOT_FULL_IPL, NULL);
280 		else if (strcmp(cmd, "mpipl") == 0)
281 			rc = opal_cec_reboot2(OPAL_REBOOT_MPIPL, NULL);
282 		else if (strcmp(cmd, "error") == 0)
283 			rc = opal_cec_reboot2(OPAL_REBOOT_PLATFORM_ERROR, NULL);
284 		else if (strcmp(cmd, "fast") == 0)
285 			rc = opal_cec_reboot2(OPAL_REBOOT_FAST, NULL);
286 		else
287 			rc = OPAL_UNSUPPORTED;
288 
289 		if (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
290 			/* Opal is busy wait for some time and retry */
291 			opal_poll_events(NULL);
292 			mdelay(10);
293 
294 		} else	if (cmd && rc) {
295 			/* Unknown error while issuing reboot */
296 			if (rc == OPAL_UNSUPPORTED)
297 				pr_err("Unsupported '%s' reboot.\n", cmd);
298 			else
299 				pr_err("Unable to issue '%s' reboot. Err=%ld\n",
300 				       cmd, rc);
301 			pr_info("Forcing a cec-reboot\n");
302 			cmd = NULL;
303 			rc = OPAL_BUSY;
304 
305 		} else if (rc != OPAL_SUCCESS) {
306 			/* Unknown error while issuing cec-reboot */
307 			pr_err("Unable to reboot. Err=%ld\n", rc);
308 		}
309 
310 	} while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT);
311 
312 	for (;;)
313 		opal_poll_events(NULL);
314 }
315 
316 static void __noreturn pnv_power_off(void)
317 {
318 	long rc = OPAL_BUSY;
319 
320 	pnv_prepare_going_down();
321 
322 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
323 		rc = opal_cec_power_down(0);
324 		if (rc == OPAL_BUSY_EVENT)
325 			opal_poll_events(NULL);
326 		else
327 			mdelay(10);
328 	}
329 	for (;;)
330 		opal_poll_events(NULL);
331 }
332 
333 static void __noreturn pnv_halt(void)
334 {
335 	pnv_power_off();
336 }
337 
338 static void pnv_progress(char *s, unsigned short hex)
339 {
340 }
341 
342 static void pnv_shutdown(void)
343 {
344 	/* Let the PCI code clear up IODA tables */
345 	pnv_pci_shutdown();
346 
347 	/*
348 	 * Stop OPAL activity: Unregister all OPAL interrupts so they
349 	 * don't fire up while we kexec and make sure all potentially
350 	 * DMA'ing ops are complete (such as dump retrieval).
351 	 */
352 	opal_shutdown();
353 }
354 
355 #ifdef CONFIG_KEXEC_CORE
356 static void pnv_kexec_wait_secondaries_down(void)
357 {
358 	int my_cpu, i, notified = -1;
359 
360 	my_cpu = get_cpu();
361 
362 	for_each_online_cpu(i) {
363 		uint8_t status;
364 		int64_t rc, timeout = 1000;
365 
366 		if (i == my_cpu)
367 			continue;
368 
369 		for (;;) {
370 			rc = opal_query_cpu_status(get_hard_smp_processor_id(i),
371 						   &status);
372 			if (rc != OPAL_SUCCESS || status != OPAL_THREAD_STARTED)
373 				break;
374 			barrier();
375 			if (i != notified) {
376 				printk(KERN_INFO "kexec: waiting for cpu %d "
377 				       "(physical %d) to enter OPAL\n",
378 				       i, paca_ptrs[i]->hw_cpu_id);
379 				notified = i;
380 			}
381 
382 			/*
383 			 * On crash secondaries might be unreachable or hung,
384 			 * so timeout if we've waited too long
385 			 * */
386 			mdelay(1);
387 			if (timeout-- == 0) {
388 				printk(KERN_ERR "kexec: timed out waiting for "
389 				       "cpu %d (physical %d) to enter OPAL\n",
390 				       i, paca_ptrs[i]->hw_cpu_id);
391 				break;
392 			}
393 		}
394 	}
395 }
396 
397 static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)
398 {
399 	u64 reinit_flags;
400 
401 	if (xive_enabled())
402 		xive_teardown_cpu();
403 	else
404 		xics_kexec_teardown_cpu(secondary);
405 
406 	/* On OPAL, we return all CPUs to firmware */
407 	if (!firmware_has_feature(FW_FEATURE_OPAL))
408 		return;
409 
410 	if (secondary) {
411 		/* Return secondary CPUs to firmware on OPAL v3 */
412 		mb();
413 		get_paca()->kexec_state = KEXEC_STATE_REAL_MODE;
414 		mb();
415 
416 		/* Return the CPU to OPAL */
417 		opal_return_cpu();
418 	} else {
419 		/* Primary waits for the secondaries to have reached OPAL */
420 		pnv_kexec_wait_secondaries_down();
421 
422 		/* Switch XIVE back to emulation mode */
423 		if (xive_enabled())
424 			xive_shutdown();
425 
426 		/*
427 		 * We might be running as little-endian - now that interrupts
428 		 * are disabled, reset the HILE bit to big-endian so we don't
429 		 * take interrupts in the wrong endian later
430 		 *
431 		 * We reinit to enable both radix and hash on P9 to ensure
432 		 * the mode used by the next kernel is always supported.
433 		 */
434 		reinit_flags = OPAL_REINIT_CPUS_HILE_BE;
435 		if (cpu_has_feature(CPU_FTR_ARCH_300))
436 			reinit_flags |= OPAL_REINIT_CPUS_MMU_RADIX |
437 				OPAL_REINIT_CPUS_MMU_HASH;
438 		opal_reinit_cpus(reinit_flags);
439 	}
440 }
441 #endif /* CONFIG_KEXEC_CORE */
442 
443 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
444 static unsigned long pnv_memory_block_size(void)
445 {
446 	/*
447 	 * We map the kernel linear region with 1GB large pages on radix. For
448 	 * memory hot unplug to work our memory block size must be at least
449 	 * this size.
450 	 */
451 	if (radix_enabled())
452 		return radix_mem_block_size;
453 	else
454 		return 256UL * 1024 * 1024;
455 }
456 #endif
457 
458 static void __init pnv_setup_machdep_opal(void)
459 {
460 	ppc_md.get_boot_time = opal_get_boot_time;
461 	ppc_md.restart = pnv_restart;
462 	pm_power_off = pnv_power_off;
463 	ppc_md.halt = pnv_halt;
464 	/* ppc_md.system_reset_exception gets filled in by pnv_smp_init() */
465 	ppc_md.machine_check_exception = opal_machine_check;
466 	ppc_md.mce_check_early_recovery = opal_mce_check_early_recovery;
467 	if (opal_check_token(OPAL_HANDLE_HMI2))
468 		ppc_md.hmi_exception_early = opal_hmi_exception_early2;
469 	else
470 		ppc_md.hmi_exception_early = opal_hmi_exception_early;
471 	ppc_md.handle_hmi_exception = opal_handle_hmi_exception;
472 }
473 
474 static int __init pnv_probe(void)
475 {
476 	if (!of_machine_is_compatible("ibm,powernv"))
477 		return 0;
478 
479 	if (firmware_has_feature(FW_FEATURE_OPAL))
480 		pnv_setup_machdep_opal();
481 
482 	pr_debug("PowerNV detected !\n");
483 
484 	pnv_init();
485 
486 	return 1;
487 }
488 
489 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
490 void __init pnv_tm_init(void)
491 {
492 	if (!firmware_has_feature(FW_FEATURE_OPAL) ||
493 	    !pvr_version_is(PVR_POWER9) ||
494 	    early_cpu_has_feature(CPU_FTR_TM))
495 		return;
496 
497 	if (opal_reinit_cpus(OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED) != OPAL_SUCCESS)
498 		return;
499 
500 	pr_info("Enabling TM (Transactional Memory) with Suspend Disabled\n");
501 	cur_cpu_spec->cpu_features |= CPU_FTR_TM;
502 	/* Make sure "normal" HTM is off (it should be) */
503 	cur_cpu_spec->cpu_user_features2 &= ~PPC_FEATURE2_HTM;
504 	/* Turn on no suspend mode, and HTM no SC */
505 	cur_cpu_spec->cpu_user_features2 |= PPC_FEATURE2_HTM_NO_SUSPEND | \
506 					    PPC_FEATURE2_HTM_NOSC;
507 	tm_suspend_disabled = true;
508 }
509 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
510 
511 /*
512  * Returns the cpu frequency for 'cpu' in Hz. This is used by
513  * /proc/cpuinfo
514  */
515 static unsigned long pnv_get_proc_freq(unsigned int cpu)
516 {
517 	unsigned long ret_freq;
518 
519 	ret_freq = cpufreq_get(cpu) * 1000ul;
520 
521 	/*
522 	 * If the backend cpufreq driver does not exist,
523          * then fallback to old way of reporting the clockrate.
524 	 */
525 	if (!ret_freq)
526 		ret_freq = ppc_proc_freq;
527 	return ret_freq;
528 }
529 
530 static long pnv_machine_check_early(struct pt_regs *regs)
531 {
532 	long handled = 0;
533 
534 	if (cur_cpu_spec && cur_cpu_spec->machine_check_early)
535 		handled = cur_cpu_spec->machine_check_early(regs);
536 
537 	return handled;
538 }
539 
540 define_machine(powernv) {
541 	.name			= "PowerNV",
542 	.probe			= pnv_probe,
543 	.setup_arch		= pnv_setup_arch,
544 	.init_IRQ		= pnv_init_IRQ,
545 	.show_cpuinfo		= pnv_show_cpuinfo,
546 	.get_proc_freq          = pnv_get_proc_freq,
547 	.discover_phbs		= pnv_pci_init,
548 	.progress		= pnv_progress,
549 	.machine_shutdown	= pnv_shutdown,
550 	.power_save             = NULL,
551 	.calibrate_decr		= generic_calibrate_decr,
552 	.machine_check_early	= pnv_machine_check_early,
553 #ifdef CONFIG_KEXEC_CORE
554 	.kexec_cpu_down		= pnv_kexec_cpu_down,
555 #endif
556 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
557 	.memory_block_size	= pnv_memory_block_size,
558 #endif
559 };
560