ghes_edac.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * GHES/EDAC Linux driver
  4 *
  5 * Copyright (c) 2013 by Mauro Carvalho Chehab
  6 *
  7 * Red Hat Inc. https://www.redhat.com
  8 */
  9
 10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 11
 12#include <acpi/ghes.h>
 13#include <linux/edac.h>
 14#include <linux/dmi.h>
 15#include "edac_module.h"
 16#include <ras/ras_event.h>
 17#include <linux/notifier.h>
 18#include <linux/string.h>
 19
 20#define OTHER_DETAIL_LEN	400
 21
 22struct ghes_pvt {
 23	struct mem_ctl_info *mci;
 24
 25	/* Buffers for the error handling routine */
 26	char other_detail[OTHER_DETAIL_LEN];
 27	char msg[80];
 28};
 29
 30static refcount_t ghes_refcount = REFCOUNT_INIT(0);
 31
 32/*
 33 * Access to ghes_pvt must be protected by ghes_lock. The spinlock
 34 * also provides the necessary (implicit) memory barrier for the SMP
 35 * case to make the pointer visible on another CPU.
 36 */
 37static struct ghes_pvt *ghes_pvt;
 38
 39/*
 40 * This driver's representation of the system hardware, as collected
 41 * from DMI.
 42 */
 43static struct ghes_hw_desc {
 44	int num_dimms;
 45	struct dimm_info *dimms;
 46} ghes_hw;
 47
 48/* GHES registration mutex */
 49static DEFINE_MUTEX(ghes_reg_mutex);
 50
 51/*
 52 * Sync with other, potentially concurrent callers of
 53 * ghes_edac_report_mem_error(). We don't know what the
 54 * "inventive" firmware would do.
 55 */
 56static DEFINE_SPINLOCK(ghes_lock);
 57
 58static bool system_scanned;
 59
 60static struct list_head *ghes_devs;
 61
 62/* Memory Device - Type 17 of SMBIOS spec */
 63struct memdev_dmi_entry {
 64	u8 type;
 65	u8 length;
 66	u16 handle;
 67	u16 phys_mem_array_handle;
 68	u16 mem_err_info_handle;
 69	u16 total_width;
 70	u16 data_width;
 71	u16 size;
 72	u8 form_factor;
 73	u8 device_set;
 74	u8 device_locator;
 75	u8 bank_locator;
 76	u8 memory_type;
 77	u16 type_detail;
 78	u16 speed;
 79	u8 manufacturer;
 80	u8 serial_number;
 81	u8 asset_tag;
 82	u8 part_number;
 83	u8 attributes;
 84	u32 extended_size;
 85	u16 conf_mem_clk_speed;
 86} __attribute__((__packed__));
 87
 88static struct dimm_info *find_dimm_by_handle(struct mem_ctl_info *mci, u16 handle)
 89{
 90	struct dimm_info *dimm;
 91
 92	mci_for_each_dimm(mci, dimm) {
 93		if (dimm->smbios_handle == handle)
 94			return dimm;
 95	}
 96
 97	return NULL;
 98}
 99
100static void dimm_setup_label(struct dimm_info *dimm, u16 handle)
101{
102	const char *bank = NULL, *device = NULL;
103
104	dmi_memdev_name(handle, &bank, &device);
105
106	/*
107	 * Set to a NULL string when both bank and device are zero. In this case,
108	 * the label assigned by default will be preserved.
109	 */
110	snprintf(dimm->label, sizeof(dimm->label), "%s%s%s",
111		 (bank && *bank) ? bank : "",
112		 (bank && *bank && device && *device) ? " " : "",
113		 (device && *device) ? device : "");
114}
115
116static void assign_dmi_dimm_info(struct dimm_info *dimm, struct memdev_dmi_entry *entry)
117{
118	u16 rdr_mask = BIT(7) | BIT(13);
119
120	if (entry->size == 0xffff) {
121		pr_info("Can't get DIMM%i size\n", dimm->idx);
122		dimm->nr_pages = MiB_TO_PAGES(32);/* Unknown */
123	} else if (entry->size == 0x7fff) {
124		dimm->nr_pages = MiB_TO_PAGES(entry->extended_size);
125	} else {
126		if (entry->size & BIT(15))
127			dimm->nr_pages = MiB_TO_PAGES((entry->size & 0x7fff) << 10);
128		else
129			dimm->nr_pages = MiB_TO_PAGES(entry->size);
130	}
131
132	switch (entry->memory_type) {
133	case 0x12:
134		if (entry->type_detail & BIT(13))
135			dimm->mtype = MEM_RDDR;
136		else
137			dimm->mtype = MEM_DDR;
138		break;
139	case 0x13:
140		if (entry->type_detail & BIT(13))
141			dimm->mtype = MEM_RDDR2;
142		else
143			dimm->mtype = MEM_DDR2;
144		break;
145	case 0x14:
146		dimm->mtype = MEM_FB_DDR2;
147		break;
148	case 0x18:
149		if (entry->type_detail & BIT(12))
150			dimm->mtype = MEM_NVDIMM;
151		else if (entry->type_detail & BIT(13))
152			dimm->mtype = MEM_RDDR3;
153		else
154			dimm->mtype = MEM_DDR3;
155		break;
156	case 0x1a:
157		if (entry->type_detail & BIT(12))
158			dimm->mtype = MEM_NVDIMM;
159		else if (entry->type_detail & BIT(13))
160			dimm->mtype = MEM_RDDR4;
161		else
162			dimm->mtype = MEM_DDR4;
163		break;
164	default:
165		if (entry->type_detail & BIT(6))
166			dimm->mtype = MEM_RMBS;
167		else if ((entry->type_detail & rdr_mask) == rdr_mask)
168			dimm->mtype = MEM_RDR;
169		else if (entry->type_detail & BIT(7))
170			dimm->mtype = MEM_SDR;
171		else if (entry->type_detail & BIT(9))
172			dimm->mtype = MEM_EDO;
173		else
174			dimm->mtype = MEM_UNKNOWN;
175	}
176
177	/*
178	 * Actually, we can only detect if the memory has bits for
179	 * checksum or not
180	 */
181	if (entry->total_width == entry->data_width)
182		dimm->edac_mode = EDAC_NONE;
183	else
184		dimm->edac_mode = EDAC_SECDED;
185
186	dimm->dtype = DEV_UNKNOWN;
187	dimm->grain = 128;		/* Likely, worse case */
188
189	dimm_setup_label(dimm, entry->handle);
190
191	if (dimm->nr_pages) {
192		edac_dbg(1, "DIMM%i: %s size = %d MB%s\n",
193			dimm->idx, edac_mem_types[dimm->mtype],
194			PAGES_TO_MiB(dimm->nr_pages),
195			(dimm->edac_mode != EDAC_NONE) ? "(ECC)" : "");
196		edac_dbg(2, "\ttype %d, detail 0x%02x, width %d(total %d)\n",
197			entry->memory_type, entry->type_detail,
198			entry->total_width, entry->data_width);
199	}
200
201	dimm->smbios_handle = entry->handle;
202}
203
204static void enumerate_dimms(const struct dmi_header *dh, void *arg)
205{
206	struct memdev_dmi_entry *entry = (struct memdev_dmi_entry *)dh;
207	struct ghes_hw_desc *hw = (struct ghes_hw_desc *)arg;
208	struct dimm_info *d;
209
210	if (dh->type != DMI_ENTRY_MEM_DEVICE)
211		return;
212
213	/* Enlarge the array with additional 16 */
214	if (!hw->num_dimms || !(hw->num_dimms % 16)) {
215		struct dimm_info *new;
216
217		new = krealloc_array(hw->dimms, hw->num_dimms + 16,
218				     sizeof(struct dimm_info), GFP_KERNEL);
219		if (!new) {
220			WARN_ON_ONCE(1);
221			return;
222		}
223
224		hw->dimms = new;
225	}
226
227	d = &hw->dimms[hw->num_dimms];
228	d->idx = hw->num_dimms;
229
230	assign_dmi_dimm_info(d, entry);
231
232	hw->num_dimms++;
233}
234
235static void ghes_scan_system(void)
236{
237	if (system_scanned)
238		return;
239
240	dmi_walk(enumerate_dimms, &ghes_hw);
241
242	system_scanned = true;
243}
244
245static int print_mem_error_other_detail(const struct cper_sec_mem_err *mem, char *msg,
246					const char *location, unsigned int len)
247{
248	u32 n;
249
250	if (!msg)
251		return 0;
252
253	n = 0;
254	len -= 1;
255
256	n += scnprintf(msg + n, len - n, "APEI location: %s ", location);
257
258	if (!(mem->validation_bits & CPER_MEM_VALID_ERROR_STATUS))
259		goto out;
260
261	n += scnprintf(msg + n, len - n, "status(0x%016llx): ", mem->error_status);
262	n += scnprintf(msg + n, len - n, "%s ", cper_mem_err_status_str(mem->error_status));
263
264out:
265	msg[n] = '\0';
266
267	return n;
268}
269
270static int ghes_edac_report_mem_error(struct notifier_block *nb,
271				      unsigned long val, void *data)
272{
273	struct cper_sec_mem_err *mem_err = (struct cper_sec_mem_err *)data;
274	struct cper_mem_err_compact cmem;
275	struct edac_raw_error_desc *e;
276	struct mem_ctl_info *mci;
277	unsigned long sev = val;
278	struct ghes_pvt *pvt;
279	unsigned long flags;
280	char *p;
281
282	/*
283	 * We can do the locking below because GHES defers error processing
284	 * from NMI to IRQ context. Whenever that changes, we'd at least
285	 * know.
286	 */
287	if (WARN_ON_ONCE(in_nmi()))
288		return NOTIFY_OK;
289
290	spin_lock_irqsave(&ghes_lock, flags);
291
292	pvt = ghes_pvt;
293	if (!pvt)
294		goto unlock;
295
296	mci = pvt->mci;
297	e = &mci->error_desc;
298
299	/* Cleans the error report buffer */
300	memset(e, 0, sizeof (*e));
301	e->error_count = 1;
302	e->grain = 1;
303	e->msg = pvt->msg;
304	e->other_detail = pvt->other_detail;
305	e->top_layer = -1;
306	e->mid_layer = -1;
307	e->low_layer = -1;
308	*pvt->other_detail = '\0';
309	*pvt->msg = '\0';
310
311	switch (sev) {
312	case GHES_SEV_CORRECTED:
313		e->type = HW_EVENT_ERR_CORRECTED;
314		break;
315	case GHES_SEV_RECOVERABLE:
316		e->type = HW_EVENT_ERR_UNCORRECTED;
317		break;
318	case GHES_SEV_PANIC:
319		e->type = HW_EVENT_ERR_FATAL;
320		break;
321	default:
322	case GHES_SEV_NO:
323		e->type = HW_EVENT_ERR_INFO;
324	}
325
326	edac_dbg(1, "error validation_bits: 0x%08llx\n",
327		 (long long)mem_err->validation_bits);
328
329	/* Error type, mapped on e->msg */
330	if (mem_err->validation_bits & CPER_MEM_VALID_ERROR_TYPE) {
331		u8 etype = mem_err->error_type;
332
333		p = pvt->msg;
334		p += snprintf(p, sizeof(pvt->msg), "%s", cper_mem_err_type_str(etype));
335	} else {
336		strscpy(pvt->msg, "unknown error");
337	}
338
339	/* Error address */
340	if (mem_err->validation_bits & CPER_MEM_VALID_PA) {
341		e->page_frame_number = PHYS_PFN(mem_err->physical_addr);
342		e->offset_in_page = offset_in_page(mem_err->physical_addr);
343	}
344
345	/* Error grain */
346	if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK)
347		e->grain = ~mem_err->physical_addr_mask + 1;
348
349	/* Memory error location, mapped on e->location */
350	p = e->location;
351	cper_mem_err_pack(mem_err, &cmem);
352	p += cper_mem_err_location(&cmem, p);
353
354	if (mem_err->validation_bits & CPER_MEM_VALID_MODULE_HANDLE) {
355		struct dimm_info *dimm;
356
357		p += cper_dimm_err_location(&cmem, p);
358		dimm = find_dimm_by_handle(mci, mem_err->mem_dev_handle);
359		if (dimm) {
360			e->top_layer = dimm->idx;
361			strscpy(e->label, dimm->label);
362		}
363	}
364	if (p > e->location)
365		*(p - 1) = '\0';
366
367	if (!*e->label)
368		strscpy(e->label, "unknown memory");
369
370	/* All other fields are mapped on e->other_detail */
371	p = pvt->other_detail;
372	p += print_mem_error_other_detail(mem_err, p, e->location, OTHER_DETAIL_LEN);
373	if (p > pvt->other_detail)
374		*(p - 1) = '\0';
375
376	edac_raw_mc_handle_error(e);
377
378unlock:
379	spin_unlock_irqrestore(&ghes_lock, flags);
380
381	return NOTIFY_OK;
382}
383
384static struct notifier_block ghes_edac_mem_err_nb = {
385	.notifier_call	= ghes_edac_report_mem_error,
386	.priority	= 0,
387};
388
389static int ghes_edac_register(struct device *dev)
390{
391	bool fake = false;
392	struct mem_ctl_info *mci;
393	struct ghes_pvt *pvt;
394	struct edac_mc_layer layers[1];
395	unsigned long flags;
396	int rc = 0;
397
398	/* finish another registration/unregistration instance first */
399	mutex_lock(&ghes_reg_mutex);
400
401	/*
402	 * We have only one logical memory controller to which all DIMMs belong.
403	 */
404	if (refcount_inc_not_zero(&ghes_refcount))
405		goto unlock;
406
407	ghes_scan_system();
408
409	/* Check if we've got a bogus BIOS */
410	if (!ghes_hw.num_dimms) {
411		fake = true;
412		ghes_hw.num_dimms = 1;
413	}
414
415	layers[0].type = EDAC_MC_LAYER_ALL_MEM;
416	layers[0].size = ghes_hw.num_dimms;
417	layers[0].is_virt_csrow = true;
418
419	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers, sizeof(struct ghes_pvt));
420	if (!mci) {
421		pr_info("Can't allocate memory for EDAC data\n");
422		rc = -ENOMEM;
423		goto unlock;
424	}
425
426	pvt		= mci->pvt_info;
427	pvt->mci	= mci;
428
429	mci->pdev = dev;
430	mci->mtype_cap = MEM_FLAG_EMPTY;
431	mci->edac_ctl_cap = EDAC_FLAG_NONE;
432	mci->edac_cap = EDAC_FLAG_NONE;
433	mci->mod_name = "ghes_edac.c";
434	mci->ctl_name = "ghes_edac";
435	mci->dev_name = "ghes";
436
437	if (fake) {
438		pr_info("This system has a very crappy BIOS: It doesn't even list the DIMMS.\n");
439		pr_info("Its SMBIOS info is wrong. It is doubtful that the error report would\n");
440		pr_info("work on such system. Use this driver with caution\n");
441	}
442
443	pr_info("This system has %d DIMM sockets.\n", ghes_hw.num_dimms);
444
445	if (!fake) {
446		struct dimm_info *src, *dst;
447		int i = 0;
448
449		mci_for_each_dimm(mci, dst) {
450			src = &ghes_hw.dimms[i];
451
452			dst->idx	   = src->idx;
453			dst->smbios_handle = src->smbios_handle;
454			dst->nr_pages	   = src->nr_pages;
455			dst->mtype	   = src->mtype;
456			dst->edac_mode	   = src->edac_mode;
457			dst->dtype	   = src->dtype;
458			dst->grain	   = src->grain;
459
460			/*
461			 * If no src->label, preserve default label assigned
462			 * from EDAC core.
463			 */
464			if (strlen(src->label))
465				memcpy(dst->label, src->label, sizeof(src->label));
466
467			i++;
468		}
469
470	} else {
471		struct dimm_info *dimm = edac_get_dimm(mci, 0, 0, 0);
472
473		dimm->nr_pages = 1;
474		dimm->grain = 128;
475		dimm->mtype = MEM_UNKNOWN;
476		dimm->dtype = DEV_UNKNOWN;
477		dimm->edac_mode = EDAC_SECDED;
478	}
479
480	rc = edac_mc_add_mc(mci);
481	if (rc < 0) {
482		pr_info("Can't register with the EDAC core\n");
483		edac_mc_free(mci);
484		rc = -ENODEV;
485		goto unlock;
486	}
487
488	spin_lock_irqsave(&ghes_lock, flags);
489	ghes_pvt = pvt;
490	spin_unlock_irqrestore(&ghes_lock, flags);
491
492	ghes_register_report_chain(&ghes_edac_mem_err_nb);
493
494	/* only set on success */
495	refcount_set(&ghes_refcount, 1);
496
497unlock:
498
499	/* Not needed anymore */
500	kfree(ghes_hw.dimms);
501	ghes_hw.dimms = NULL;
502
503	mutex_unlock(&ghes_reg_mutex);
504
505	return rc;
506}
507
508static void ghes_edac_unregister(struct ghes *ghes)
509{
510	struct mem_ctl_info *mci;
511	unsigned long flags;
512
513	mutex_lock(&ghes_reg_mutex);
514
515	system_scanned = false;
516	memset(&ghes_hw, 0, sizeof(struct ghes_hw_desc));
517
518	if (!refcount_dec_and_test(&ghes_refcount))
519		goto unlock;
520
521	/*
522	 * Wait for the irq handler being finished.
523	 */
524	spin_lock_irqsave(&ghes_lock, flags);
525	mci = ghes_pvt ? ghes_pvt->mci : NULL;
526	ghes_pvt = NULL;
527	spin_unlock_irqrestore(&ghes_lock, flags);
528
529	if (!mci)
530		goto unlock;
531
532	mci = edac_mc_del_mc(mci->pdev);
533	if (mci)
534		edac_mc_free(mci);
535
536	ghes_unregister_report_chain(&ghes_edac_mem_err_nb);
537
538unlock:
539	mutex_unlock(&ghes_reg_mutex);
540}
541
542static int __init ghes_edac_init(void)
543{
544	struct ghes *g, *g_tmp;
545
546	ghes_devs = ghes_get_devices();
547	if (!ghes_devs)
548		return -ENODEV;
549
550	if (list_empty(ghes_devs)) {
551		pr_info("GHES probing device list is empty\n");
552		return -ENODEV;
553	}
554
555	list_for_each_entry_safe(g, g_tmp, ghes_devs, elist) {
556		ghes_edac_register(g->dev);
557	}
558
559	return 0;
560}
561module_init(ghes_edac_init);
562
563static void __exit ghes_edac_exit(void)
564{
565	struct ghes *g, *g_tmp;
566
567	list_for_each_entry_safe(g, g_tmp, ghes_devs, elist) {
568		ghes_edac_unregister(g);
569	}
570}
571module_exit(ghes_edac_exit);
572
573MODULE_LICENSE("GPL");
574MODULE_DESCRIPTION("Output ACPI APEI/GHES BIOS detected errors via EDAC");