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Linux/drivers/acpi/apei/ghes.c

  1 /*
  2  * APEI Generic Hardware Error Source support
  3  *
  4  * Generic Hardware Error Source provides a way to report platform
  5  * hardware errors (such as that from chipset). It works in so called
  6  * "Firmware First" mode, that is, hardware errors are reported to
  7  * firmware firstly, then reported to Linux by firmware. This way,
  8  * some non-standard hardware error registers or non-standard hardware
  9  * link can be checked by firmware to produce more hardware error
 10  * information for Linux.
 11  *
 12  * For more information about Generic Hardware Error Source, please
 13  * refer to ACPI Specification version 4.0, section 17.3.2.6
 14  *
 15  * Copyright 2010,2011 Intel Corp.
 16  *   Author: Huang Ying <ying.huang@intel.com>
 17  *
 18  * This program is free software; you can redistribute it and/or
 19  * modify it under the terms of the GNU General Public License version
 20  * 2 as published by the Free Software Foundation;
 21  *
 22  * This program is distributed in the hope that it will be useful,
 23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 25  * GNU General Public License for more details.
 26  */
 27 
 28 #include <linux/kernel.h>
 29 #include <linux/module.h>
 30 #include <linux/init.h>
 31 #include <linux/acpi.h>
 32 #include <linux/io.h>
 33 #include <linux/interrupt.h>
 34 #include <linux/timer.h>
 35 #include <linux/cper.h>
 36 #include <linux/kdebug.h>
 37 #include <linux/platform_device.h>
 38 #include <linux/mutex.h>
 39 #include <linux/ratelimit.h>
 40 #include <linux/vmalloc.h>
 41 #include <linux/irq_work.h>
 42 #include <linux/llist.h>
 43 #include <linux/genalloc.h>
 44 #include <linux/pci.h>
 45 #include <linux/aer.h>
 46 #include <linux/nmi.h>
 47 
 48 #include <acpi/ghes.h>
 49 #include <acpi/apei.h>
 50 #include <asm/tlbflush.h>
 51 
 52 #include "apei-internal.h"
 53 
 54 #define GHES_PFX        "GHES: "
 55 
 56 #define GHES_ESTATUS_MAX_SIZE           65536
 57 #define GHES_ESOURCE_PREALLOC_MAX_SIZE  65536
 58 
 59 #define GHES_ESTATUS_POOL_MIN_ALLOC_ORDER 3
 60 
 61 /* This is just an estimation for memory pool allocation */
 62 #define GHES_ESTATUS_CACHE_AVG_SIZE     512
 63 
 64 #define GHES_ESTATUS_CACHES_SIZE        4
 65 
 66 #define GHES_ESTATUS_IN_CACHE_MAX_NSEC  10000000000ULL
 67 /* Prevent too many caches are allocated because of RCU */
 68 #define GHES_ESTATUS_CACHE_ALLOCED_MAX  (GHES_ESTATUS_CACHES_SIZE * 3 / 2)
 69 
 70 #define GHES_ESTATUS_CACHE_LEN(estatus_len)                     \
 71         (sizeof(struct ghes_estatus_cache) + (estatus_len))
 72 #define GHES_ESTATUS_FROM_CACHE(estatus_cache)                  \
 73         ((struct acpi_hest_generic_status *)                            \
 74          ((struct ghes_estatus_cache *)(estatus_cache) + 1))
 75 
 76 #define GHES_ESTATUS_NODE_LEN(estatus_len)                      \
 77         (sizeof(struct ghes_estatus_node) + (estatus_len))
 78 #define GHES_ESTATUS_FROM_NODE(estatus_node)                    \
 79         ((struct acpi_hest_generic_status *)                            \
 80          ((struct ghes_estatus_node *)(estatus_node) + 1))
 81 
 82 bool ghes_disable;
 83 module_param_named(disable, ghes_disable, bool, 0);
 84 
 85 /*
 86  * All error sources notified with SCI shares one notifier function,
 87  * so they need to be linked and checked one by one.  This is applied
 88  * to NMI too.
 89  *
 90  * RCU is used for these lists, so ghes_list_mutex is only used for
 91  * list changing, not for traversing.
 92  */
 93 static LIST_HEAD(ghes_sci);
 94 static DEFINE_MUTEX(ghes_list_mutex);
 95 
 96 /*
 97  * Because the memory area used to transfer hardware error information
 98  * from BIOS to Linux can be determined only in NMI, IRQ or timer
 99  * handler, but general ioremap can not be used in atomic context, so
100  * a special version of atomic ioremap is implemented for that.
101  */
102 
103 /*
104  * Two virtual pages are used, one for IRQ/PROCESS context, the other for
105  * NMI context (optionally).
106  */
107 #ifdef CONFIG_HAVE_ACPI_APEI_NMI
108 #define GHES_IOREMAP_PAGES           2
109 #else
110 #define GHES_IOREMAP_PAGES           1
111 #endif
112 #define GHES_IOREMAP_IRQ_PAGE(base)     (base)
113 #define GHES_IOREMAP_NMI_PAGE(base)     ((base) + PAGE_SIZE)
114 
115 /* virtual memory area for atomic ioremap */
116 static struct vm_struct *ghes_ioremap_area;
117 /*
118  * These 2 spinlock is used to prevent atomic ioremap virtual memory
119  * area from being mapped simultaneously.
120  */
121 static DEFINE_RAW_SPINLOCK(ghes_ioremap_lock_nmi);
122 static DEFINE_SPINLOCK(ghes_ioremap_lock_irq);
123 
124 static struct gen_pool *ghes_estatus_pool;
125 static unsigned long ghes_estatus_pool_size_request;
126 
127 static struct ghes_estatus_cache *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
128 static atomic_t ghes_estatus_cache_alloced;
129 
130 static int ghes_ioremap_init(void)
131 {
132         ghes_ioremap_area = __get_vm_area(PAGE_SIZE * GHES_IOREMAP_PAGES,
133                 VM_IOREMAP, VMALLOC_START, VMALLOC_END);
134         if (!ghes_ioremap_area) {
135                 pr_err(GHES_PFX "Failed to allocate virtual memory area for atomic ioremap.\n");
136                 return -ENOMEM;
137         }
138 
139         return 0;
140 }
141 
142 static void ghes_ioremap_exit(void)
143 {
144         free_vm_area(ghes_ioremap_area);
145 }
146 
147 static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn)
148 {
149         unsigned long vaddr;
150 
151         vaddr = (unsigned long)GHES_IOREMAP_NMI_PAGE(ghes_ioremap_area->addr);
152         ioremap_page_range(vaddr, vaddr + PAGE_SIZE,
153                            pfn << PAGE_SHIFT, PAGE_KERNEL);
154 
155         return (void __iomem *)vaddr;
156 }
157 
158 static void __iomem *ghes_ioremap_pfn_irq(u64 pfn)
159 {
160         unsigned long vaddr, paddr;
161         pgprot_t prot;
162 
163         vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr);
164 
165         paddr = pfn << PAGE_SHIFT;
166         prot = arch_apei_get_mem_attribute(paddr);
167 
168         ioremap_page_range(vaddr, vaddr + PAGE_SIZE, paddr, prot);
169 
170         return (void __iomem *)vaddr;
171 }
172 
173 static void ghes_iounmap_nmi(void __iomem *vaddr_ptr)
174 {
175         unsigned long vaddr = (unsigned long __force)vaddr_ptr;
176         void *base = ghes_ioremap_area->addr;
177 
178         BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_NMI_PAGE(base));
179         unmap_kernel_range_noflush(vaddr, PAGE_SIZE);
180         arch_apei_flush_tlb_one(vaddr);
181 }
182 
183 static void ghes_iounmap_irq(void __iomem *vaddr_ptr)
184 {
185         unsigned long vaddr = (unsigned long __force)vaddr_ptr;
186         void *base = ghes_ioremap_area->addr;
187 
188         BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_IRQ_PAGE(base));
189         unmap_kernel_range_noflush(vaddr, PAGE_SIZE);
190         arch_apei_flush_tlb_one(vaddr);
191 }
192 
193 static int ghes_estatus_pool_init(void)
194 {
195         ghes_estatus_pool = gen_pool_create(GHES_ESTATUS_POOL_MIN_ALLOC_ORDER, -1);
196         if (!ghes_estatus_pool)
197                 return -ENOMEM;
198         return 0;
199 }
200 
201 static void ghes_estatus_pool_free_chunk_page(struct gen_pool *pool,
202                                               struct gen_pool_chunk *chunk,
203                                               void *data)
204 {
205         free_page(chunk->start_addr);
206 }
207 
208 static void ghes_estatus_pool_exit(void)
209 {
210         gen_pool_for_each_chunk(ghes_estatus_pool,
211                                 ghes_estatus_pool_free_chunk_page, NULL);
212         gen_pool_destroy(ghes_estatus_pool);
213 }
214 
215 static int ghes_estatus_pool_expand(unsigned long len)
216 {
217         unsigned long i, pages, size, addr;
218         int ret;
219 
220         ghes_estatus_pool_size_request += PAGE_ALIGN(len);
221         size = gen_pool_size(ghes_estatus_pool);
222         if (size >= ghes_estatus_pool_size_request)
223                 return 0;
224         pages = (ghes_estatus_pool_size_request - size) / PAGE_SIZE;
225         for (i = 0; i < pages; i++) {
226                 addr = __get_free_page(GFP_KERNEL);
227                 if (!addr)
228                         return -ENOMEM;
229                 ret = gen_pool_add(ghes_estatus_pool, addr, PAGE_SIZE, -1);
230                 if (ret)
231                         return ret;
232         }
233 
234         return 0;
235 }
236 
237 static struct ghes *ghes_new(struct acpi_hest_generic *generic)
238 {
239         struct ghes *ghes;
240         unsigned int error_block_length;
241         int rc;
242 
243         ghes = kzalloc(sizeof(*ghes), GFP_KERNEL);
244         if (!ghes)
245                 return ERR_PTR(-ENOMEM);
246         ghes->generic = generic;
247         rc = apei_map_generic_address(&generic->error_status_address);
248         if (rc)
249                 goto err_free;
250         error_block_length = generic->error_block_length;
251         if (error_block_length > GHES_ESTATUS_MAX_SIZE) {
252                 pr_warning(FW_WARN GHES_PFX
253                            "Error status block length is too long: %u for "
254                            "generic hardware error source: %d.\n",
255                            error_block_length, generic->header.source_id);
256                 error_block_length = GHES_ESTATUS_MAX_SIZE;
257         }
258         ghes->estatus = kmalloc(error_block_length, GFP_KERNEL);
259         if (!ghes->estatus) {
260                 rc = -ENOMEM;
261                 goto err_unmap;
262         }
263 
264         return ghes;
265 
266 err_unmap:
267         apei_unmap_generic_address(&generic->error_status_address);
268 err_free:
269         kfree(ghes);
270         return ERR_PTR(rc);
271 }
272 
273 static void ghes_fini(struct ghes *ghes)
274 {
275         kfree(ghes->estatus);
276         apei_unmap_generic_address(&ghes->generic->error_status_address);
277 }
278 
279 static inline int ghes_severity(int severity)
280 {
281         switch (severity) {
282         case CPER_SEV_INFORMATIONAL:
283                 return GHES_SEV_NO;
284         case CPER_SEV_CORRECTED:
285                 return GHES_SEV_CORRECTED;
286         case CPER_SEV_RECOVERABLE:
287                 return GHES_SEV_RECOVERABLE;
288         case CPER_SEV_FATAL:
289                 return GHES_SEV_PANIC;
290         default:
291                 /* Unknown, go panic */
292                 return GHES_SEV_PANIC;
293         }
294 }
295 
296 static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
297                                   int from_phys)
298 {
299         void __iomem *vaddr;
300         unsigned long flags = 0;
301         int in_nmi = in_nmi();
302         u64 offset;
303         u32 trunk;
304 
305         while (len > 0) {
306                 offset = paddr - (paddr & PAGE_MASK);
307                 if (in_nmi) {
308                         raw_spin_lock(&ghes_ioremap_lock_nmi);
309                         vaddr = ghes_ioremap_pfn_nmi(paddr >> PAGE_SHIFT);
310                 } else {
311                         spin_lock_irqsave(&ghes_ioremap_lock_irq, flags);
312                         vaddr = ghes_ioremap_pfn_irq(paddr >> PAGE_SHIFT);
313                 }
314                 trunk = PAGE_SIZE - offset;
315                 trunk = min(trunk, len);
316                 if (from_phys)
317                         memcpy_fromio(buffer, vaddr + offset, trunk);
318                 else
319                         memcpy_toio(vaddr + offset, buffer, trunk);
320                 len -= trunk;
321                 paddr += trunk;
322                 buffer += trunk;
323                 if (in_nmi) {
324                         ghes_iounmap_nmi(vaddr);
325                         raw_spin_unlock(&ghes_ioremap_lock_nmi);
326                 } else {
327                         ghes_iounmap_irq(vaddr);
328                         spin_unlock_irqrestore(&ghes_ioremap_lock_irq, flags);
329                 }
330         }
331 }
332 
333 static int ghes_read_estatus(struct ghes *ghes, int silent)
334 {
335         struct acpi_hest_generic *g = ghes->generic;
336         u64 buf_paddr;
337         u32 len;
338         int rc;
339 
340         rc = apei_read(&buf_paddr, &g->error_status_address);
341         if (rc) {
342                 if (!silent && printk_ratelimit())
343                         pr_warning(FW_WARN GHES_PFX
344 "Failed to read error status block address for hardware error source: %d.\n",
345                                    g->header.source_id);
346                 return -EIO;
347         }
348         if (!buf_paddr)
349                 return -ENOENT;
350 
351         ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
352                               sizeof(*ghes->estatus), 1);
353         if (!ghes->estatus->block_status)
354                 return -ENOENT;
355 
356         ghes->buffer_paddr = buf_paddr;
357         ghes->flags |= GHES_TO_CLEAR;
358 
359         rc = -EIO;
360         len = cper_estatus_len(ghes->estatus);
361         if (len < sizeof(*ghes->estatus))
362                 goto err_read_block;
363         if (len > ghes->generic->error_block_length)
364                 goto err_read_block;
365         if (cper_estatus_check_header(ghes->estatus))
366                 goto err_read_block;
367         ghes_copy_tofrom_phys(ghes->estatus + 1,
368                               buf_paddr + sizeof(*ghes->estatus),
369                               len - sizeof(*ghes->estatus), 1);
370         if (cper_estatus_check(ghes->estatus))
371                 goto err_read_block;
372         rc = 0;
373 
374 err_read_block:
375         if (rc && !silent && printk_ratelimit())
376                 pr_warning(FW_WARN GHES_PFX
377                            "Failed to read error status block!\n");
378         return rc;
379 }
380 
381 static void ghes_clear_estatus(struct ghes *ghes)
382 {
383         ghes->estatus->block_status = 0;
384         if (!(ghes->flags & GHES_TO_CLEAR))
385                 return;
386         ghes_copy_tofrom_phys(ghes->estatus, ghes->buffer_paddr,
387                               sizeof(ghes->estatus->block_status), 0);
388         ghes->flags &= ~GHES_TO_CLEAR;
389 }
390 
391 static void ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata, int sev)
392 {
393 #ifdef CONFIG_ACPI_APEI_MEMORY_FAILURE
394         unsigned long pfn;
395         int flags = -1;
396         int sec_sev = ghes_severity(gdata->error_severity);
397         struct cper_sec_mem_err *mem_err;
398         mem_err = (struct cper_sec_mem_err *)(gdata + 1);
399 
400         if (!(mem_err->validation_bits & CPER_MEM_VALID_PA))
401                 return;
402 
403         pfn = mem_err->physical_addr >> PAGE_SHIFT;
404         if (!pfn_valid(pfn)) {
405                 pr_warn_ratelimited(FW_WARN GHES_PFX
406                 "Invalid address in generic error data: %#llx\n",
407                 mem_err->physical_addr);
408                 return;
409         }
410 
411         /* iff following two events can be handled properly by now */
412         if (sec_sev == GHES_SEV_CORRECTED &&
413             (gdata->flags & CPER_SEC_ERROR_THRESHOLD_EXCEEDED))
414                 flags = MF_SOFT_OFFLINE;
415         if (sev == GHES_SEV_RECOVERABLE && sec_sev == GHES_SEV_RECOVERABLE)
416                 flags = 0;
417 
418         if (flags != -1)
419                 memory_failure_queue(pfn, 0, flags);
420 #endif
421 }
422 
423 static void ghes_do_proc(struct ghes *ghes,
424                          const struct acpi_hest_generic_status *estatus)
425 {
426         int sev, sec_sev;
427         struct acpi_hest_generic_data *gdata;
428 
429         sev = ghes_severity(estatus->error_severity);
430         apei_estatus_for_each_section(estatus, gdata) {
431                 sec_sev = ghes_severity(gdata->error_severity);
432                 if (!uuid_le_cmp(*(uuid_le *)gdata->section_type,
433                                  CPER_SEC_PLATFORM_MEM)) {
434                         struct cper_sec_mem_err *mem_err;
435                         mem_err = (struct cper_sec_mem_err *)(gdata+1);
436                         ghes_edac_report_mem_error(ghes, sev, mem_err);
437 
438                         arch_apei_report_mem_error(sev, mem_err);
439                         ghes_handle_memory_failure(gdata, sev);
440                 }
441 #ifdef CONFIG_ACPI_APEI_PCIEAER
442                 else if (!uuid_le_cmp(*(uuid_le *)gdata->section_type,
443                                       CPER_SEC_PCIE)) {
444                         struct cper_sec_pcie *pcie_err;
445                         pcie_err = (struct cper_sec_pcie *)(gdata+1);
446                         if (sev == GHES_SEV_RECOVERABLE &&
447                             sec_sev == GHES_SEV_RECOVERABLE &&
448                             pcie_err->validation_bits & CPER_PCIE_VALID_DEVICE_ID &&
449                             pcie_err->validation_bits & CPER_PCIE_VALID_AER_INFO) {
450                                 unsigned int devfn;
451                                 int aer_severity;
452 
453                                 devfn = PCI_DEVFN(pcie_err->device_id.device,
454                                                   pcie_err->device_id.function);
455                                 aer_severity = cper_severity_to_aer(sev);
456 
457                                 /*
458                                  * If firmware reset the component to contain
459                                  * the error, we must reinitialize it before
460                                  * use, so treat it as a fatal AER error.
461                                  */
462                                 if (gdata->flags & CPER_SEC_RESET)
463                                         aer_severity = AER_FATAL;
464 
465                                 aer_recover_queue(pcie_err->device_id.segment,
466                                                   pcie_err->device_id.bus,
467                                                   devfn, aer_severity,
468                                                   (struct aer_capability_regs *)
469                                                   pcie_err->aer_info);
470                         }
471 
472                 }
473 #endif
474         }
475 }
476 
477 static void __ghes_print_estatus(const char *pfx,
478                                  const struct acpi_hest_generic *generic,
479                                  const struct acpi_hest_generic_status *estatus)
480 {
481         static atomic_t seqno;
482         unsigned int curr_seqno;
483         char pfx_seq[64];
484 
485         if (pfx == NULL) {
486                 if (ghes_severity(estatus->error_severity) <=
487                     GHES_SEV_CORRECTED)
488                         pfx = KERN_WARNING;
489                 else
490                         pfx = KERN_ERR;
491         }
492         curr_seqno = atomic_inc_return(&seqno);
493         snprintf(pfx_seq, sizeof(pfx_seq), "%s{%u}" HW_ERR, pfx, curr_seqno);
494         printk("%s""Hardware error from APEI Generic Hardware Error Source: %d\n",
495                pfx_seq, generic->header.source_id);
496         cper_estatus_print(pfx_seq, estatus);
497 }
498 
499 static int ghes_print_estatus(const char *pfx,
500                               const struct acpi_hest_generic *generic,
501                               const struct acpi_hest_generic_status *estatus)
502 {
503         /* Not more than 2 messages every 5 seconds */
504         static DEFINE_RATELIMIT_STATE(ratelimit_corrected, 5*HZ, 2);
505         static DEFINE_RATELIMIT_STATE(ratelimit_uncorrected, 5*HZ, 2);
506         struct ratelimit_state *ratelimit;
507 
508         if (ghes_severity(estatus->error_severity) <= GHES_SEV_CORRECTED)
509                 ratelimit = &ratelimit_corrected;
510         else
511                 ratelimit = &ratelimit_uncorrected;
512         if (__ratelimit(ratelimit)) {
513                 __ghes_print_estatus(pfx, generic, estatus);
514                 return 1;
515         }
516         return 0;
517 }
518 
519 /*
520  * GHES error status reporting throttle, to report more kinds of
521  * errors, instead of just most frequently occurred errors.
522  */
523 static int ghes_estatus_cached(struct acpi_hest_generic_status *estatus)
524 {
525         u32 len;
526         int i, cached = 0;
527         unsigned long long now;
528         struct ghes_estatus_cache *cache;
529         struct acpi_hest_generic_status *cache_estatus;
530 
531         len = cper_estatus_len(estatus);
532         rcu_read_lock();
533         for (i = 0; i < GHES_ESTATUS_CACHES_SIZE; i++) {
534                 cache = rcu_dereference(ghes_estatus_caches[i]);
535                 if (cache == NULL)
536                         continue;
537                 if (len != cache->estatus_len)
538                         continue;
539                 cache_estatus = GHES_ESTATUS_FROM_CACHE(cache);
540                 if (memcmp(estatus, cache_estatus, len))
541                         continue;
542                 atomic_inc(&cache->count);
543                 now = sched_clock();
544                 if (now - cache->time_in < GHES_ESTATUS_IN_CACHE_MAX_NSEC)
545                         cached = 1;
546                 break;
547         }
548         rcu_read_unlock();
549         return cached;
550 }
551 
552 static struct ghes_estatus_cache *ghes_estatus_cache_alloc(
553         struct acpi_hest_generic *generic,
554         struct acpi_hest_generic_status *estatus)
555 {
556         int alloced;
557         u32 len, cache_len;
558         struct ghes_estatus_cache *cache;
559         struct acpi_hest_generic_status *cache_estatus;
560 
561         alloced = atomic_add_return(1, &ghes_estatus_cache_alloced);
562         if (alloced > GHES_ESTATUS_CACHE_ALLOCED_MAX) {
563                 atomic_dec(&ghes_estatus_cache_alloced);
564                 return NULL;
565         }
566         len = cper_estatus_len(estatus);
567         cache_len = GHES_ESTATUS_CACHE_LEN(len);
568         cache = (void *)gen_pool_alloc(ghes_estatus_pool, cache_len);
569         if (!cache) {
570                 atomic_dec(&ghes_estatus_cache_alloced);
571                 return NULL;
572         }
573         cache_estatus = GHES_ESTATUS_FROM_CACHE(cache);
574         memcpy(cache_estatus, estatus, len);
575         cache->estatus_len = len;
576         atomic_set(&cache->count, 0);
577         cache->generic = generic;
578         cache->time_in = sched_clock();
579         return cache;
580 }
581 
582 static void ghes_estatus_cache_free(struct ghes_estatus_cache *cache)
583 {
584         u32 len;
585 
586         len = cper_estatus_len(GHES_ESTATUS_FROM_CACHE(cache));
587         len = GHES_ESTATUS_CACHE_LEN(len);
588         gen_pool_free(ghes_estatus_pool, (unsigned long)cache, len);
589         atomic_dec(&ghes_estatus_cache_alloced);
590 }
591 
592 static void ghes_estatus_cache_rcu_free(struct rcu_head *head)
593 {
594         struct ghes_estatus_cache *cache;
595 
596         cache = container_of(head, struct ghes_estatus_cache, rcu);
597         ghes_estatus_cache_free(cache);
598 }
599 
600 static void ghes_estatus_cache_add(
601         struct acpi_hest_generic *generic,
602         struct acpi_hest_generic_status *estatus)
603 {
604         int i, slot = -1, count;
605         unsigned long long now, duration, period, max_period = 0;
606         struct ghes_estatus_cache *cache, *slot_cache = NULL, *new_cache;
607 
608         new_cache = ghes_estatus_cache_alloc(generic, estatus);
609         if (new_cache == NULL)
610                 return;
611         rcu_read_lock();
612         now = sched_clock();
613         for (i = 0; i < GHES_ESTATUS_CACHES_SIZE; i++) {
614                 cache = rcu_dereference(ghes_estatus_caches[i]);
615                 if (cache == NULL) {
616                         slot = i;
617                         slot_cache = NULL;
618                         break;
619                 }
620                 duration = now - cache->time_in;
621                 if (duration >= GHES_ESTATUS_IN_CACHE_MAX_NSEC) {
622                         slot = i;
623                         slot_cache = cache;
624                         break;
625                 }
626                 count = atomic_read(&cache->count);
627                 period = duration;
628                 do_div(period, (count + 1));
629                 if (period > max_period) {
630                         max_period = period;
631                         slot = i;
632                         slot_cache = cache;
633                 }
634         }
635         /* new_cache must be put into array after its contents are written */
636         smp_wmb();
637         if (slot != -1 && cmpxchg(ghes_estatus_caches + slot,
638                                   slot_cache, new_cache) == slot_cache) {
639                 if (slot_cache)
640                         call_rcu(&slot_cache->rcu, ghes_estatus_cache_rcu_free);
641         } else
642                 ghes_estatus_cache_free(new_cache);
643         rcu_read_unlock();
644 }
645 
646 static int ghes_proc(struct ghes *ghes)
647 {
648         int rc;
649 
650         rc = ghes_read_estatus(ghes, 0);
651         if (rc)
652                 goto out;
653         if (!ghes_estatus_cached(ghes->estatus)) {
654                 if (ghes_print_estatus(NULL, ghes->generic, ghes->estatus))
655                         ghes_estatus_cache_add(ghes->generic, ghes->estatus);
656         }
657         ghes_do_proc(ghes, ghes->estatus);
658 out:
659         ghes_clear_estatus(ghes);
660         return 0;
661 }
662 
663 static void ghes_add_timer(struct ghes *ghes)
664 {
665         struct acpi_hest_generic *g = ghes->generic;
666         unsigned long expire;
667 
668         if (!g->notify.poll_interval) {
669                 pr_warning(FW_WARN GHES_PFX "Poll interval is 0 for generic hardware error source: %d, disabled.\n",
670                            g->header.source_id);
671                 return;
672         }
673         expire = jiffies + msecs_to_jiffies(g->notify.poll_interval);
674         ghes->timer.expires = round_jiffies_relative(expire);
675         add_timer(&ghes->timer);
676 }
677 
678 static void ghes_poll_func(unsigned long data)
679 {
680         struct ghes *ghes = (void *)data;
681 
682         ghes_proc(ghes);
683         if (!(ghes->flags & GHES_EXITING))
684                 ghes_add_timer(ghes);
685 }
686 
687 static irqreturn_t ghes_irq_func(int irq, void *data)
688 {
689         struct ghes *ghes = data;
690         int rc;
691 
692         rc = ghes_proc(ghes);
693         if (rc)
694                 return IRQ_NONE;
695 
696         return IRQ_HANDLED;
697 }
698 
699 static int ghes_notify_sci(struct notifier_block *this,
700                                   unsigned long event, void *data)
701 {
702         struct ghes *ghes;
703         int ret = NOTIFY_DONE;
704 
705         rcu_read_lock();
706         list_for_each_entry_rcu(ghes, &ghes_sci, list) {
707                 if (!ghes_proc(ghes))
708                         ret = NOTIFY_OK;
709         }
710         rcu_read_unlock();
711 
712         return ret;
713 }
714 
715 static struct notifier_block ghes_notifier_sci = {
716         .notifier_call = ghes_notify_sci,
717 };
718 
719 #ifdef CONFIG_HAVE_ACPI_APEI_NMI
720 /*
721  * printk is not safe in NMI context.  So in NMI handler, we allocate
722  * required memory from lock-less memory allocator
723  * (ghes_estatus_pool), save estatus into it, put them into lock-less
724  * list (ghes_estatus_llist), then delay printk into IRQ context via
725  * irq_work (ghes_proc_irq_work).  ghes_estatus_size_request record
726  * required pool size by all NMI error source.
727  */
728 static struct llist_head ghes_estatus_llist;
729 static struct irq_work ghes_proc_irq_work;
730 
731 /*
732  * NMI may be triggered on any CPU, so ghes_in_nmi is used for
733  * having only one concurrent reader.
734  */
735 static atomic_t ghes_in_nmi = ATOMIC_INIT(0);
736 
737 static LIST_HEAD(ghes_nmi);
738 
739 static int ghes_panic_timeout   __read_mostly = 30;
740 
741 static void ghes_proc_in_irq(struct irq_work *irq_work)
742 {
743         struct llist_node *llnode, *next;
744         struct ghes_estatus_node *estatus_node;
745         struct acpi_hest_generic *generic;
746         struct acpi_hest_generic_status *estatus;
747         u32 len, node_len;
748 
749         llnode = llist_del_all(&ghes_estatus_llist);
750         /*
751          * Because the time order of estatus in list is reversed,
752          * revert it back to proper order.
753          */
754         llnode = llist_reverse_order(llnode);
755         while (llnode) {
756                 next = llnode->next;
757                 estatus_node = llist_entry(llnode, struct ghes_estatus_node,
758                                            llnode);
759                 estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
760                 len = cper_estatus_len(estatus);
761                 node_len = GHES_ESTATUS_NODE_LEN(len);
762                 ghes_do_proc(estatus_node->ghes, estatus);
763                 if (!ghes_estatus_cached(estatus)) {
764                         generic = estatus_node->generic;
765                         if (ghes_print_estatus(NULL, generic, estatus))
766                                 ghes_estatus_cache_add(generic, estatus);
767                 }
768                 gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node,
769                               node_len);
770                 llnode = next;
771         }
772 }
773 
774 static void ghes_print_queued_estatus(void)
775 {
776         struct llist_node *llnode;
777         struct ghes_estatus_node *estatus_node;
778         struct acpi_hest_generic *generic;
779         struct acpi_hest_generic_status *estatus;
780         u32 len, node_len;
781 
782         llnode = llist_del_all(&ghes_estatus_llist);
783         /*
784          * Because the time order of estatus in list is reversed,
785          * revert it back to proper order.
786          */
787         llnode = llist_reverse_order(llnode);
788         while (llnode) {
789                 estatus_node = llist_entry(llnode, struct ghes_estatus_node,
790                                            llnode);
791                 estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
792                 len = cper_estatus_len(estatus);
793                 node_len = GHES_ESTATUS_NODE_LEN(len);
794                 generic = estatus_node->generic;
795                 ghes_print_estatus(NULL, generic, estatus);
796                 llnode = llnode->next;
797         }
798 }
799 
800 /* Save estatus for further processing in IRQ context */
801 static void __process_error(struct ghes *ghes)
802 {
803 #ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
804         u32 len, node_len;
805         struct ghes_estatus_node *estatus_node;
806         struct acpi_hest_generic_status *estatus;
807 
808         if (ghes_estatus_cached(ghes->estatus))
809                 return;
810 
811         len = cper_estatus_len(ghes->estatus);
812         node_len = GHES_ESTATUS_NODE_LEN(len);
813 
814         estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len);
815         if (!estatus_node)
816                 return;
817 
818         estatus_node->ghes = ghes;
819         estatus_node->generic = ghes->generic;
820         estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
821         memcpy(estatus, ghes->estatus, len);
822         llist_add(&estatus_node->llnode, &ghes_estatus_llist);
823 #endif
824 }
825 
826 static void __ghes_panic(struct ghes *ghes)
827 {
828         oops_begin();
829         ghes_print_queued_estatus();
830         __ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
831 
832         /* reboot to log the error! */
833         if (panic_timeout == 0)
834                 panic_timeout = ghes_panic_timeout;
835         panic("Fatal hardware error!");
836 }
837 
838 static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
839 {
840         struct ghes *ghes;
841         int sev, ret = NMI_DONE;
842 
843         if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
844                 return ret;
845 
846         list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
847                 if (ghes_read_estatus(ghes, 1)) {
848                         ghes_clear_estatus(ghes);
849                         continue;
850                 }
851 
852                 sev = ghes_severity(ghes->estatus->error_severity);
853                 if (sev >= GHES_SEV_PANIC)
854                         __ghes_panic(ghes);
855 
856                 if (!(ghes->flags & GHES_TO_CLEAR))
857                         continue;
858 
859                 __process_error(ghes);
860                 ghes_clear_estatus(ghes);
861 
862                 ret = NMI_HANDLED;
863         }
864 
865 #ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
866         irq_work_queue(&ghes_proc_irq_work);
867 #endif
868         atomic_dec(&ghes_in_nmi);
869         return ret;
870 }
871 
872 static unsigned long ghes_esource_prealloc_size(
873         const struct acpi_hest_generic *generic)
874 {
875         unsigned long block_length, prealloc_records, prealloc_size;
876 
877         block_length = min_t(unsigned long, generic->error_block_length,
878                              GHES_ESTATUS_MAX_SIZE);
879         prealloc_records = max_t(unsigned long,
880                                  generic->records_to_preallocate, 1);
881         prealloc_size = min_t(unsigned long, block_length * prealloc_records,
882                               GHES_ESOURCE_PREALLOC_MAX_SIZE);
883 
884         return prealloc_size;
885 }
886 
887 static void ghes_estatus_pool_shrink(unsigned long len)
888 {
889         ghes_estatus_pool_size_request -= PAGE_ALIGN(len);
890 }
891 
892 static void ghes_nmi_add(struct ghes *ghes)
893 {
894         unsigned long len;
895 
896         len = ghes_esource_prealloc_size(ghes->generic);
897         ghes_estatus_pool_expand(len);
898         mutex_lock(&ghes_list_mutex);
899         if (list_empty(&ghes_nmi))
900                 register_nmi_handler(NMI_LOCAL, ghes_notify_nmi, 0, "ghes");
901         list_add_rcu(&ghes->list, &ghes_nmi);
902         mutex_unlock(&ghes_list_mutex);
903 }
904 
905 static void ghes_nmi_remove(struct ghes *ghes)
906 {
907         unsigned long len;
908 
909         mutex_lock(&ghes_list_mutex);
910         list_del_rcu(&ghes->list);
911         if (list_empty(&ghes_nmi))
912                 unregister_nmi_handler(NMI_LOCAL, "ghes");
913         mutex_unlock(&ghes_list_mutex);
914         /*
915          * To synchronize with NMI handler, ghes can only be
916          * freed after NMI handler finishes.
917          */
918         synchronize_rcu();
919         len = ghes_esource_prealloc_size(ghes->generic);
920         ghes_estatus_pool_shrink(len);
921 }
922 
923 static void ghes_nmi_init_cxt(void)
924 {
925         init_irq_work(&ghes_proc_irq_work, ghes_proc_in_irq);
926 }
927 #else /* CONFIG_HAVE_ACPI_APEI_NMI */
928 static inline void ghes_nmi_add(struct ghes *ghes)
929 {
930         pr_err(GHES_PFX "ID: %d, trying to add NMI notification which is not supported!\n",
931                ghes->generic->header.source_id);
932         BUG();
933 }
934 
935 static inline void ghes_nmi_remove(struct ghes *ghes)
936 {
937         pr_err(GHES_PFX "ID: %d, trying to remove NMI notification which is not supported!\n",
938                ghes->generic->header.source_id);
939         BUG();
940 }
941 
942 static inline void ghes_nmi_init_cxt(void)
943 {
944 }
945 #endif /* CONFIG_HAVE_ACPI_APEI_NMI */
946 
947 static int ghes_probe(struct platform_device *ghes_dev)
948 {
949         struct acpi_hest_generic *generic;
950         struct ghes *ghes = NULL;
951 
952         int rc = -EINVAL;
953 
954         generic = *(struct acpi_hest_generic **)ghes_dev->dev.platform_data;
955         if (!generic->enabled)
956                 return -ENODEV;
957 
958         switch (generic->notify.type) {
959         case ACPI_HEST_NOTIFY_POLLED:
960         case ACPI_HEST_NOTIFY_EXTERNAL:
961         case ACPI_HEST_NOTIFY_SCI:
962                 break;
963         case ACPI_HEST_NOTIFY_NMI:
964                 if (!IS_ENABLED(CONFIG_HAVE_ACPI_APEI_NMI)) {
965                         pr_warn(GHES_PFX "Generic hardware error source: %d notified via NMI interrupt is not supported!\n",
966                                 generic->header.source_id);
967                         goto err;
968                 }
969                 break;
970         case ACPI_HEST_NOTIFY_LOCAL:
971                 pr_warning(GHES_PFX "Generic hardware error source: %d notified via local interrupt is not supported!\n",
972                            generic->header.source_id);
973                 goto err;
974         default:
975                 pr_warning(FW_WARN GHES_PFX "Unknown notification type: %u for generic hardware error source: %d\n",
976                            generic->notify.type, generic->header.source_id);
977                 goto err;
978         }
979 
980         rc = -EIO;
981         if (generic->error_block_length <
982             sizeof(struct acpi_hest_generic_status)) {
983                 pr_warning(FW_BUG GHES_PFX "Invalid error block length: %u for generic hardware error source: %d\n",
984                            generic->error_block_length,
985                            generic->header.source_id);
986                 goto err;
987         }
988         ghes = ghes_new(generic);
989         if (IS_ERR(ghes)) {
990                 rc = PTR_ERR(ghes);
991                 ghes = NULL;
992                 goto err;
993         }
994 
995         rc = ghes_edac_register(ghes, &ghes_dev->dev);
996         if (rc < 0)
997                 goto err;
998 
999         switch (generic->notify.type) {
1000         case ACPI_HEST_NOTIFY_POLLED:
1001                 ghes->timer.function = ghes_poll_func;
1002                 ghes->timer.data = (unsigned long)ghes;
1003                 init_timer_deferrable(&ghes->timer);
1004                 ghes_add_timer(ghes);
1005                 break;
1006         case ACPI_HEST_NOTIFY_EXTERNAL:
1007                 /* External interrupt vector is GSI */
1008                 rc = acpi_gsi_to_irq(generic->notify.vector, &ghes->irq);
1009                 if (rc) {
1010                         pr_err(GHES_PFX "Failed to map GSI to IRQ for generic hardware error source: %d\n",
1011                                generic->header.source_id);
1012                         goto err_edac_unreg;
1013                 }
1014                 rc = request_irq(ghes->irq, ghes_irq_func, 0, "GHES IRQ", ghes);
1015                 if (rc) {
1016                         pr_err(GHES_PFX "Failed to register IRQ for generic hardware error source: %d\n",
1017                                generic->header.source_id);
1018                         goto err_edac_unreg;
1019                 }
1020                 break;
1021         case ACPI_HEST_NOTIFY_SCI:
1022                 mutex_lock(&ghes_list_mutex);
1023                 if (list_empty(&ghes_sci))
1024                         register_acpi_hed_notifier(&ghes_notifier_sci);
1025                 list_add_rcu(&ghes->list, &ghes_sci);
1026                 mutex_unlock(&ghes_list_mutex);
1027                 break;
1028         case ACPI_HEST_NOTIFY_NMI:
1029                 ghes_nmi_add(ghes);
1030                 break;
1031         default:
1032                 BUG();
1033         }
1034         platform_set_drvdata(ghes_dev, ghes);
1035 
1036         return 0;
1037 err_edac_unreg:
1038         ghes_edac_unregister(ghes);
1039 err:
1040         if (ghes) {
1041                 ghes_fini(ghes);
1042                 kfree(ghes);
1043         }
1044         return rc;
1045 }
1046 
1047 static int ghes_remove(struct platform_device *ghes_dev)
1048 {
1049         struct ghes *ghes;
1050         struct acpi_hest_generic *generic;
1051 
1052         ghes = platform_get_drvdata(ghes_dev);
1053         generic = ghes->generic;
1054 
1055         ghes->flags |= GHES_EXITING;
1056         switch (generic->notify.type) {
1057         case ACPI_HEST_NOTIFY_POLLED:
1058                 del_timer_sync(&ghes->timer);
1059                 break;
1060         case ACPI_HEST_NOTIFY_EXTERNAL:
1061                 free_irq(ghes->irq, ghes);
1062                 break;
1063         case ACPI_HEST_NOTIFY_SCI:
1064                 mutex_lock(&ghes_list_mutex);
1065                 list_del_rcu(&ghes->list);
1066                 if (list_empty(&ghes_sci))
1067                         unregister_acpi_hed_notifier(&ghes_notifier_sci);
1068                 mutex_unlock(&ghes_list_mutex);
1069                 break;
1070         case ACPI_HEST_NOTIFY_NMI:
1071                 ghes_nmi_remove(ghes);
1072                 break;
1073         default:
1074                 BUG();
1075                 break;
1076         }
1077 
1078         ghes_fini(ghes);
1079 
1080         ghes_edac_unregister(ghes);
1081 
1082         kfree(ghes);
1083 
1084         platform_set_drvdata(ghes_dev, NULL);
1085 
1086         return 0;
1087 }
1088 
1089 static struct platform_driver ghes_platform_driver = {
1090         .driver         = {
1091                 .name   = "GHES",
1092         },
1093         .probe          = ghes_probe,
1094         .remove         = ghes_remove,
1095 };
1096 
1097 static int __init ghes_init(void)
1098 {
1099         int rc;
1100 
1101         if (acpi_disabled)
1102                 return -ENODEV;
1103 
1104         if (hest_disable) {
1105                 pr_info(GHES_PFX "HEST is not enabled!\n");
1106                 return -EINVAL;
1107         }
1108 
1109         if (ghes_disable) {
1110                 pr_info(GHES_PFX "GHES is not enabled!\n");
1111                 return -EINVAL;
1112         }
1113 
1114         ghes_nmi_init_cxt();
1115 
1116         rc = ghes_ioremap_init();
1117         if (rc)
1118                 goto err;
1119 
1120         rc = ghes_estatus_pool_init();
1121         if (rc)
1122                 goto err_ioremap_exit;
1123 
1124         rc = ghes_estatus_pool_expand(GHES_ESTATUS_CACHE_AVG_SIZE *
1125                                       GHES_ESTATUS_CACHE_ALLOCED_MAX);
1126         if (rc)
1127                 goto err_pool_exit;
1128 
1129         rc = platform_driver_register(&ghes_platform_driver);
1130         if (rc)
1131                 goto err_pool_exit;
1132 
1133         rc = apei_osc_setup();
1134         if (rc == 0 && osc_sb_apei_support_acked)
1135                 pr_info(GHES_PFX "APEI firmware first mode is enabled by APEI bit and WHEA _OSC.\n");
1136         else if (rc == 0 && !osc_sb_apei_support_acked)
1137                 pr_info(GHES_PFX "APEI firmware first mode is enabled by WHEA _OSC.\n");
1138         else if (rc && osc_sb_apei_support_acked)
1139                 pr_info(GHES_PFX "APEI firmware first mode is enabled by APEI bit.\n");
1140         else
1141                 pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");
1142 
1143         return 0;
1144 err_pool_exit:
1145         ghes_estatus_pool_exit();
1146 err_ioremap_exit:
1147         ghes_ioremap_exit();
1148 err:
1149         return rc;
1150 }
1151 
1152 static void __exit ghes_exit(void)
1153 {
1154         platform_driver_unregister(&ghes_platform_driver);
1155         ghes_estatus_pool_exit();
1156         ghes_ioremap_exit();
1157 }
1158 
1159 module_init(ghes_init);
1160 module_exit(ghes_exit);
1161 
1162 MODULE_AUTHOR("Huang Ying");
1163 MODULE_DESCRIPTION("APEI Generic Hardware Error Source support");
1164 MODULE_LICENSE("GPL");
1165 MODULE_ALIAS("platform:GHES");
1166 

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