1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2010 Google Inc. All Rights Reserved.
4 * Author: dlaurie@google.com (Duncan Laurie)
5 *
6 * Re-worked to expose sysfs APIs by mikew@google.com (Mike Waychison)
7 *
8 * EFI SMI interface for Google platforms
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/types.h>
14 #include <linux/device.h>
15 #include <linux/platform_device.h>
16 #include <linux/errno.h>
17 #include <linux/string.h>
18 #include <linux/spinlock.h>
19 #include <linux/dma-mapping.h>
20 #include <linux/fs.h>
21 #include <linux/slab.h>
22 #include <linux/ioctl.h>
23 #include <linux/acpi.h>
24 #include <linux/io.h>
25 #include <linux/uaccess.h>
26 #include <linux/dmi.h>
27 #include <linux/kdebug.h>
28 #include <linux/reboot.h>
29 #include <linux/efi.h>
30 #include <linux/module.h>
31 #include <linux/ucs2_string.h>
32 #include <linux/suspend.h>
33
34 #define GSMI_SHUTDOWN_CLEAN 0 /* Clean Shutdown */
35 /* TODO(mikew@google.com): Tie in HARDLOCKUP_DETECTOR with NMIWDT */
36 #define GSMI_SHUTDOWN_NMIWDT 1 /* NMI Watchdog */
37 #define GSMI_SHUTDOWN_PANIC 2 /* Panic */
38 #define GSMI_SHUTDOWN_OOPS 3 /* Oops */
39 #define GSMI_SHUTDOWN_DIE 4 /* Die -- No longer meaningful */
40 #define GSMI_SHUTDOWN_MCE 5 /* Machine Check */
41 #define GSMI_SHUTDOWN_SOFTWDT 6 /* Software Watchdog */
42 #define GSMI_SHUTDOWN_MBE 7 /* Uncorrected ECC */
43 #define GSMI_SHUTDOWN_TRIPLE 8 /* Triple Fault */
44
45 #define DRIVER_VERSION "1.0"
46 #define GSMI_GUID_SIZE 16
47 #define GSMI_BUF_SIZE 1024
48 #define GSMI_BUF_ALIGN sizeof(u64)
49 #define GSMI_CALLBACK 0xef
50
51 /* SMI return codes */
52 #define GSMI_SUCCESS 0x00
53 #define GSMI_UNSUPPORTED2 0x03
54 #define GSMI_LOG_FULL 0x0b
55 #define GSMI_VAR_NOT_FOUND 0x0e
56 #define GSMI_HANDSHAKE_SPIN 0x7d
57 #define GSMI_HANDSHAKE_CF 0x7e
58 #define GSMI_HANDSHAKE_NONE 0x7f
59 #define GSMI_INVALID_PARAMETER 0x82
60 #define GSMI_UNSUPPORTED 0x83
61 #define GSMI_BUFFER_TOO_SMALL 0x85
62 #define GSMI_NOT_READY 0x86
63 #define GSMI_DEVICE_ERROR 0x87
64 #define GSMI_NOT_FOUND 0x8e
65
66 #define QUIRKY_BOARD_HASH 0x78a30a50
67
68 /* Internally used commands passed to the firmware */
69 #define GSMI_CMD_GET_NVRAM_VAR 0x01
70 #define GSMI_CMD_GET_NEXT_VAR 0x02
71 #define GSMI_CMD_SET_NVRAM_VAR 0x03
72 #define GSMI_CMD_SET_EVENT_LOG 0x08
73 #define GSMI_CMD_CLEAR_EVENT_LOG 0x09
74 #define GSMI_CMD_LOG_S0IX_SUSPEND 0x0a
75 #define GSMI_CMD_LOG_S0IX_RESUME 0x0b
76 #define GSMI_CMD_CLEAR_CONFIG 0x20
77 #define GSMI_CMD_HANDSHAKE_TYPE 0xC1
78 #define GSMI_CMD_RESERVED 0xff
79
80 /* Magic entry type for kernel events */
81 #define GSMI_LOG_ENTRY_TYPE_KERNEL 0xDEAD
82
83 /* SMI buffers must be in 32bit physical address space */
84 struct gsmi_buf {
85 u8 *start; /* start of buffer */
86 size_t length; /* length of buffer */
87 u32 address; /* physical address of buffer */
88 };
89
90 static struct gsmi_device {
91 struct platform_device *pdev; /* platform device */
92 struct gsmi_buf *name_buf; /* variable name buffer */
93 struct gsmi_buf *data_buf; /* generic data buffer */
94 struct gsmi_buf *param_buf; /* parameter buffer */
95 spinlock_t lock; /* serialize access to SMIs */
96 u16 smi_cmd; /* SMI command port */
97 int handshake_type; /* firmware handler interlock type */
98 struct kmem_cache *mem_pool; /* kmem cache for gsmi_buf allocations */
99 } gsmi_dev;
100
101 /* Packed structures for communicating with the firmware */
102 struct gsmi_nvram_var_param {
103 efi_guid_t guid;
104 u32 name_ptr;
105 u32 attributes;
106 u32 data_len;
107 u32 data_ptr;
108 } __packed;
109
110 struct gsmi_get_next_var_param {
111 u8 guid[GSMI_GUID_SIZE];
112 u32 name_ptr;
113 u32 name_len;
114 } __packed;
115
116 struct gsmi_set_eventlog_param {
117 u32 data_ptr;
118 u32 data_len;
119 u32 type;
120 } __packed;
121
122 /* Event log formats */
123 struct gsmi_log_entry_type_1 {
124 u16 type;
125 u32 instance;
126 } __packed;
127
128 /*
129 * Some platforms don't have explicit SMI handshake
130 * and need to wait for SMI to complete.
131 */
132 #define GSMI_DEFAULT_SPINCOUNT 0x10000
133 static unsigned int spincount = GSMI_DEFAULT_SPINCOUNT;
134 module_param(spincount, uint, 0600);
135 MODULE_PARM_DESC(spincount,
136 "The number of loop iterations to use when using the spin handshake.");
137
138 /*
139 * Some older platforms with Apollo Lake chipsets do not support S0ix logging
140 * in their GSMI handlers, and behaved poorly when resuming via power button
141 * press if the logging was attempted. Updated firmware with proper behavior
142 * has long since shipped, removing the need for this opt-in parameter. It
143 * now exists as an opt-out parameter for folks defiantly running old
144 * firmware, or unforeseen circumstances. After the change from opt-in to
145 * opt-out has baked sufficiently, this parameter should probably be removed
146 * entirely.
147 */
148 static bool s0ix_logging_enable = true;
149 module_param(s0ix_logging_enable, bool, 0600);
150
gsmi_buf_alloc(void)151 static struct gsmi_buf *gsmi_buf_alloc(void)
152 {
153 struct gsmi_buf *smibuf;
154
155 smibuf = kzalloc(sizeof(*smibuf), GFP_KERNEL);
156 if (!smibuf) {
157 printk(KERN_ERR "gsmi: out of memory\n");
158 return NULL;
159 }
160
161 /* allocate buffer in 32bit address space */
162 smibuf->start = kmem_cache_alloc(gsmi_dev.mem_pool, GFP_KERNEL);
163 if (!smibuf->start) {
164 printk(KERN_ERR "gsmi: failed to allocate name buffer\n");
165 kfree(smibuf);
166 return NULL;
167 }
168
169 /* fill in the buffer handle */
170 smibuf->length = GSMI_BUF_SIZE;
171 smibuf->address = (u32)virt_to_phys(smibuf->start);
172
173 return smibuf;
174 }
175
gsmi_buf_free(struct gsmi_buf * smibuf)176 static void gsmi_buf_free(struct gsmi_buf *smibuf)
177 {
178 if (smibuf) {
179 if (smibuf->start)
180 kmem_cache_free(gsmi_dev.mem_pool, smibuf->start);
181 kfree(smibuf);
182 }
183 }
184
185 /*
186 * Make a call to gsmi func(sub). GSMI error codes are translated to
187 * in-kernel errnos (0 on success, -ERRNO on error).
188 */
gsmi_exec(u8 func,u8 sub)189 static int gsmi_exec(u8 func, u8 sub)
190 {
191 u16 cmd = (sub << 8) | func;
192 u16 result = 0;
193 int rc = 0;
194
195 /*
196 * AH : Subfunction number
197 * AL : Function number
198 * EBX : Parameter block address
199 * DX : SMI command port
200 *
201 * Three protocols here. See also the comment in gsmi_init().
202 */
203 if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_CF) {
204 /*
205 * If handshake_type == HANDSHAKE_CF then set CF on the
206 * way in and wait for the handler to clear it; this avoids
207 * corrupting register state on those chipsets which have
208 * a delay between writing the SMI trigger register and
209 * entering SMM.
210 */
211 asm volatile (
212 "stc\n"
213 "outb %%al, %%dx\n"
214 "1: jc 1b\n"
215 : "=a" (result)
216 : "0" (cmd),
217 "d" (gsmi_dev.smi_cmd),
218 "b" (gsmi_dev.param_buf->address)
219 : "memory", "cc"
220 );
221 } else if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_SPIN) {
222 /*
223 * If handshake_type == HANDSHAKE_SPIN we spin a
224 * hundred-ish usecs to ensure the SMI has triggered.
225 */
226 asm volatile (
227 "outb %%al, %%dx\n"
228 "1: loop 1b\n"
229 : "=a" (result)
230 : "0" (cmd),
231 "d" (gsmi_dev.smi_cmd),
232 "b" (gsmi_dev.param_buf->address),
233 "c" (spincount)
234 : "memory", "cc"
235 );
236 } else {
237 /*
238 * If handshake_type == HANDSHAKE_NONE we do nothing;
239 * either we don't need to or it's legacy firmware that
240 * doesn't understand the CF protocol.
241 */
242 asm volatile (
243 "outb %%al, %%dx\n\t"
244 : "=a" (result)
245 : "0" (cmd),
246 "d" (gsmi_dev.smi_cmd),
247 "b" (gsmi_dev.param_buf->address)
248 : "memory", "cc"
249 );
250 }
251
252 /* check return code from SMI handler */
253 switch (result) {
254 case GSMI_SUCCESS:
255 break;
256 case GSMI_VAR_NOT_FOUND:
257 /* not really an error, but let the caller know */
258 rc = 1;
259 break;
260 case GSMI_INVALID_PARAMETER:
261 printk(KERN_ERR "gsmi: exec 0x%04x: Invalid parameter\n", cmd);
262 rc = -EINVAL;
263 break;
264 case GSMI_BUFFER_TOO_SMALL:
265 printk(KERN_ERR "gsmi: exec 0x%04x: Buffer too small\n", cmd);
266 rc = -ENOMEM;
267 break;
268 case GSMI_UNSUPPORTED:
269 case GSMI_UNSUPPORTED2:
270 if (sub != GSMI_CMD_HANDSHAKE_TYPE)
271 printk(KERN_ERR "gsmi: exec 0x%04x: Not supported\n",
272 cmd);
273 rc = -ENOSYS;
274 break;
275 case GSMI_NOT_READY:
276 printk(KERN_ERR "gsmi: exec 0x%04x: Not ready\n", cmd);
277 rc = -EBUSY;
278 break;
279 case GSMI_DEVICE_ERROR:
280 printk(KERN_ERR "gsmi: exec 0x%04x: Device error\n", cmd);
281 rc = -EFAULT;
282 break;
283 case GSMI_NOT_FOUND:
284 printk(KERN_ERR "gsmi: exec 0x%04x: Data not found\n", cmd);
285 rc = -ENOENT;
286 break;
287 case GSMI_LOG_FULL:
288 printk(KERN_ERR "gsmi: exec 0x%04x: Log full\n", cmd);
289 rc = -ENOSPC;
290 break;
291 case GSMI_HANDSHAKE_CF:
292 case GSMI_HANDSHAKE_SPIN:
293 case GSMI_HANDSHAKE_NONE:
294 rc = result;
295 break;
296 default:
297 printk(KERN_ERR "gsmi: exec 0x%04x: Unknown error 0x%04x\n",
298 cmd, result);
299 rc = -ENXIO;
300 }
301
302 return rc;
303 }
304
305 #ifdef CONFIG_EFI
306
307 static struct efivars efivars;
308
gsmi_get_variable(efi_char16_t * name,efi_guid_t * vendor,u32 * attr,unsigned long * data_size,void * data)309 static efi_status_t gsmi_get_variable(efi_char16_t *name,
310 efi_guid_t *vendor, u32 *attr,
311 unsigned long *data_size,
312 void *data)
313 {
314 struct gsmi_nvram_var_param param = {
315 .name_ptr = gsmi_dev.name_buf->address,
316 .data_ptr = gsmi_dev.data_buf->address,
317 .data_len = (u32)*data_size,
318 };
319 efi_status_t ret = EFI_SUCCESS;
320 unsigned long flags;
321 size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2);
322 int rc;
323
324 if (name_len >= GSMI_BUF_SIZE / 2)
325 return EFI_BAD_BUFFER_SIZE;
326
327 spin_lock_irqsave(&gsmi_dev.lock, flags);
328
329 /* Vendor guid */
330 memcpy(¶m.guid, vendor, sizeof(param.guid));
331
332 /* variable name, already in UTF-16 */
333 memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length);
334 memcpy(gsmi_dev.name_buf->start, name, name_len * 2);
335
336 /* data pointer */
337 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
338
339 /* parameter buffer */
340 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
341 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
342
343 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NVRAM_VAR);
344 if (rc < 0) {
345 printk(KERN_ERR "gsmi: Get Variable failed\n");
346 ret = EFI_LOAD_ERROR;
347 } else if (rc == 1) {
348 /* variable was not found */
349 ret = EFI_NOT_FOUND;
350 } else {
351 /* Get the arguments back */
352 memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param));
353
354 /* The size reported is the min of all of our buffers */
355 *data_size = min_t(unsigned long, *data_size,
356 gsmi_dev.data_buf->length);
357 *data_size = min_t(unsigned long, *data_size, param.data_len);
358
359 /* Copy data back to return buffer. */
360 memcpy(data, gsmi_dev.data_buf->start, *data_size);
361
362 /* All variables are have the following attributes */
363 *attr = EFI_VARIABLE_NON_VOLATILE |
364 EFI_VARIABLE_BOOTSERVICE_ACCESS |
365 EFI_VARIABLE_RUNTIME_ACCESS;
366 }
367
368 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
369
370 return ret;
371 }
372
gsmi_get_next_variable(unsigned long * name_size,efi_char16_t * name,efi_guid_t * vendor)373 static efi_status_t gsmi_get_next_variable(unsigned long *name_size,
374 efi_char16_t *name,
375 efi_guid_t *vendor)
376 {
377 struct gsmi_get_next_var_param param = {
378 .name_ptr = gsmi_dev.name_buf->address,
379 .name_len = gsmi_dev.name_buf->length,
380 };
381 efi_status_t ret = EFI_SUCCESS;
382 int rc;
383 unsigned long flags;
384
385 /* For the moment, only support buffers that exactly match in size */
386 if (*name_size != GSMI_BUF_SIZE)
387 return EFI_BAD_BUFFER_SIZE;
388
389 /* Let's make sure the thing is at least null-terminated */
390 if (ucs2_strnlen(name, GSMI_BUF_SIZE / 2) == GSMI_BUF_SIZE / 2)
391 return EFI_INVALID_PARAMETER;
392
393 spin_lock_irqsave(&gsmi_dev.lock, flags);
394
395 /* guid */
396 memcpy(¶m.guid, vendor, sizeof(param.guid));
397
398 /* variable name, already in UTF-16 */
399 memcpy(gsmi_dev.name_buf->start, name, *name_size);
400
401 /* parameter buffer */
402 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
403 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
404
405 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NEXT_VAR);
406 if (rc < 0) {
407 printk(KERN_ERR "gsmi: Get Next Variable Name failed\n");
408 ret = EFI_LOAD_ERROR;
409 } else if (rc == 1) {
410 /* variable not found -- end of list */
411 ret = EFI_NOT_FOUND;
412 } else {
413 /* copy variable data back to return buffer */
414 memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param));
415
416 /* Copy the name back */
417 memcpy(name, gsmi_dev.name_buf->start, GSMI_BUF_SIZE);
418 *name_size = ucs2_strnlen(name, GSMI_BUF_SIZE / 2) * 2;
419
420 /* copy guid to return buffer */
421 memcpy(vendor, ¶m.guid, sizeof(param.guid));
422 ret = EFI_SUCCESS;
423 }
424
425 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
426
427 return ret;
428 }
429
gsmi_set_variable(efi_char16_t * name,efi_guid_t * vendor,u32 attr,unsigned long data_size,void * data)430 static efi_status_t gsmi_set_variable(efi_char16_t *name,
431 efi_guid_t *vendor,
432 u32 attr,
433 unsigned long data_size,
434 void *data)
435 {
436 struct gsmi_nvram_var_param param = {
437 .name_ptr = gsmi_dev.name_buf->address,
438 .data_ptr = gsmi_dev.data_buf->address,
439 .data_len = (u32)data_size,
440 .attributes = EFI_VARIABLE_NON_VOLATILE |
441 EFI_VARIABLE_BOOTSERVICE_ACCESS |
442 EFI_VARIABLE_RUNTIME_ACCESS,
443 };
444 size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2);
445 efi_status_t ret = EFI_SUCCESS;
446 int rc;
447 unsigned long flags;
448
449 if (name_len >= GSMI_BUF_SIZE / 2)
450 return EFI_BAD_BUFFER_SIZE;
451
452 spin_lock_irqsave(&gsmi_dev.lock, flags);
453
454 /* guid */
455 memcpy(¶m.guid, vendor, sizeof(param.guid));
456
457 /* variable name, already in UTF-16 */
458 memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length);
459 memcpy(gsmi_dev.name_buf->start, name, name_len * 2);
460
461 /* data pointer */
462 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
463 memcpy(gsmi_dev.data_buf->start, data, data_size);
464
465 /* parameter buffer */
466 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
467 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
468
469 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_NVRAM_VAR);
470 if (rc < 0) {
471 printk(KERN_ERR "gsmi: Set Variable failed\n");
472 ret = EFI_INVALID_PARAMETER;
473 }
474
475 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
476
477 return ret;
478 }
479
480 static const struct efivar_operations efivar_ops = {
481 .get_variable = gsmi_get_variable,
482 .set_variable = gsmi_set_variable,
483 .get_next_variable = gsmi_get_next_variable,
484 };
485
486 #endif /* CONFIG_EFI */
487
eventlog_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t count)488 static ssize_t eventlog_write(struct file *filp, struct kobject *kobj,
489 struct bin_attribute *bin_attr,
490 char *buf, loff_t pos, size_t count)
491 {
492 struct gsmi_set_eventlog_param param = {
493 .data_ptr = gsmi_dev.data_buf->address,
494 };
495 int rc = 0;
496 unsigned long flags;
497
498 /* Pull the type out */
499 if (count < sizeof(u32))
500 return -EINVAL;
501 param.type = *(u32 *)buf;
502 buf += sizeof(u32);
503
504 /* The remaining buffer is the data payload */
505 if ((count - sizeof(u32)) > gsmi_dev.data_buf->length)
506 return -EINVAL;
507 param.data_len = count - sizeof(u32);
508
509 spin_lock_irqsave(&gsmi_dev.lock, flags);
510
511 /* data pointer */
512 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
513 memcpy(gsmi_dev.data_buf->start, buf, param.data_len);
514
515 /* parameter buffer */
516 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
517 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
518
519 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG);
520 if (rc < 0)
521 printk(KERN_ERR "gsmi: Set Event Log failed\n");
522
523 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
524
525 return (rc == 0) ? count : rc;
526
527 }
528
529 static struct bin_attribute eventlog_bin_attr = {
530 .attr = {.name = "append_to_eventlog", .mode = 0200},
531 .write = eventlog_write,
532 };
533
gsmi_clear_eventlog_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)534 static ssize_t gsmi_clear_eventlog_store(struct kobject *kobj,
535 struct kobj_attribute *attr,
536 const char *buf, size_t count)
537 {
538 int rc;
539 unsigned long flags;
540 unsigned long val;
541 struct {
542 u32 percentage;
543 u32 data_type;
544 } param;
545
546 rc = kstrtoul(buf, 0, &val);
547 if (rc)
548 return rc;
549
550 /*
551 * Value entered is a percentage, 0 through 100, anything else
552 * is invalid.
553 */
554 if (val > 100)
555 return -EINVAL;
556
557 /* data_type here selects the smbios event log. */
558 param.percentage = val;
559 param.data_type = 0;
560
561 spin_lock_irqsave(&gsmi_dev.lock, flags);
562
563 /* parameter buffer */
564 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
565 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
566
567 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_EVENT_LOG);
568
569 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
570
571 if (rc)
572 return rc;
573 return count;
574 }
575
576 static struct kobj_attribute gsmi_clear_eventlog_attr = {
577 .attr = {.name = "clear_eventlog", .mode = 0200},
578 .store = gsmi_clear_eventlog_store,
579 };
580
gsmi_clear_config_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)581 static ssize_t gsmi_clear_config_store(struct kobject *kobj,
582 struct kobj_attribute *attr,
583 const char *buf, size_t count)
584 {
585 int rc;
586 unsigned long flags;
587
588 spin_lock_irqsave(&gsmi_dev.lock, flags);
589
590 /* clear parameter buffer */
591 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
592
593 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_CONFIG);
594
595 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
596
597 if (rc)
598 return rc;
599 return count;
600 }
601
602 static struct kobj_attribute gsmi_clear_config_attr = {
603 .attr = {.name = "clear_config", .mode = 0200},
604 .store = gsmi_clear_config_store,
605 };
606
607 static const struct attribute *gsmi_attrs[] = {
608 &gsmi_clear_config_attr.attr,
609 &gsmi_clear_eventlog_attr.attr,
610 NULL,
611 };
612
gsmi_shutdown_reason(int reason)613 static int gsmi_shutdown_reason(int reason)
614 {
615 struct gsmi_log_entry_type_1 entry = {
616 .type = GSMI_LOG_ENTRY_TYPE_KERNEL,
617 .instance = reason,
618 };
619 struct gsmi_set_eventlog_param param = {
620 .data_len = sizeof(entry),
621 .type = 1,
622 };
623 static int saved_reason;
624 int rc = 0;
625 unsigned long flags;
626
627 /* avoid duplicate entries in the log */
628 if (saved_reason & (1 << reason))
629 return 0;
630
631 spin_lock_irqsave(&gsmi_dev.lock, flags);
632
633 saved_reason |= (1 << reason);
634
635 /* data pointer */
636 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
637 memcpy(gsmi_dev.data_buf->start, &entry, sizeof(entry));
638
639 /* parameter buffer */
640 param.data_ptr = gsmi_dev.data_buf->address;
641 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
642 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
643
644 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG);
645
646 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
647
648 if (rc < 0)
649 printk(KERN_ERR "gsmi: Log Shutdown Reason failed\n");
650 else
651 printk(KERN_EMERG "gsmi: Log Shutdown Reason 0x%02x\n",
652 reason);
653
654 return rc;
655 }
656
gsmi_reboot_callback(struct notifier_block * nb,unsigned long reason,void * arg)657 static int gsmi_reboot_callback(struct notifier_block *nb,
658 unsigned long reason, void *arg)
659 {
660 gsmi_shutdown_reason(GSMI_SHUTDOWN_CLEAN);
661 return NOTIFY_DONE;
662 }
663
664 static struct notifier_block gsmi_reboot_notifier = {
665 .notifier_call = gsmi_reboot_callback
666 };
667
gsmi_die_callback(struct notifier_block * nb,unsigned long reason,void * arg)668 static int gsmi_die_callback(struct notifier_block *nb,
669 unsigned long reason, void *arg)
670 {
671 if (reason == DIE_OOPS)
672 gsmi_shutdown_reason(GSMI_SHUTDOWN_OOPS);
673 return NOTIFY_DONE;
674 }
675
676 static struct notifier_block gsmi_die_notifier = {
677 .notifier_call = gsmi_die_callback
678 };
679
gsmi_panic_callback(struct notifier_block * nb,unsigned long reason,void * arg)680 static int gsmi_panic_callback(struct notifier_block *nb,
681 unsigned long reason, void *arg)
682 {
683 gsmi_shutdown_reason(GSMI_SHUTDOWN_PANIC);
684 return NOTIFY_DONE;
685 }
686
687 static struct notifier_block gsmi_panic_notifier = {
688 .notifier_call = gsmi_panic_callback,
689 };
690
691 /*
692 * This hash function was blatantly copied from include/linux/hash.h.
693 * It is used by this driver to obfuscate a board name that requires a
694 * quirk within this driver.
695 *
696 * Please do not remove this copy of the function as any changes to the
697 * global utility hash_64() function would break this driver's ability
698 * to identify a board and provide the appropriate quirk -- mikew@google.com
699 */
local_hash_64(u64 val,unsigned bits)700 static u64 __init local_hash_64(u64 val, unsigned bits)
701 {
702 u64 hash = val;
703
704 /* Sigh, gcc can't optimise this alone like it does for 32 bits. */
705 u64 n = hash;
706 n <<= 18;
707 hash -= n;
708 n <<= 33;
709 hash -= n;
710 n <<= 3;
711 hash += n;
712 n <<= 3;
713 hash -= n;
714 n <<= 4;
715 hash += n;
716 n <<= 2;
717 hash += n;
718
719 /* High bits are more random, so use them. */
720 return hash >> (64 - bits);
721 }
722
hash_oem_table_id(char s[8])723 static u32 __init hash_oem_table_id(char s[8])
724 {
725 u64 input;
726 memcpy(&input, s, 8);
727 return local_hash_64(input, 32);
728 }
729
730 static const struct dmi_system_id gsmi_dmi_table[] __initconst = {
731 {
732 .ident = "Google Board",
733 .matches = {
734 DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."),
735 },
736 },
737 {
738 .ident = "Coreboot Firmware",
739 .matches = {
740 DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
741 },
742 },
743 {}
744 };
745 MODULE_DEVICE_TABLE(dmi, gsmi_dmi_table);
746
gsmi_system_valid(void)747 static __init int gsmi_system_valid(void)
748 {
749 u32 hash;
750 u16 cmd, result;
751
752 if (!dmi_check_system(gsmi_dmi_table))
753 return -ENODEV;
754
755 /*
756 * Only newer firmware supports the gsmi interface. All older
757 * firmware that didn't support this interface used to plug the
758 * table name in the first four bytes of the oem_table_id field.
759 * Newer firmware doesn't do that though, so use that as the
760 * discriminant factor. We have to do this in order to
761 * whitewash our board names out of the public driver.
762 */
763 if (!strncmp(acpi_gbl_FADT.header.oem_table_id, "FACP", 4)) {
764 printk(KERN_INFO "gsmi: Board is too old\n");
765 return -ENODEV;
766 }
767
768 /* Disable on board with 1.0 BIOS due to Google bug 2602657 */
769 hash = hash_oem_table_id(acpi_gbl_FADT.header.oem_table_id);
770 if (hash == QUIRKY_BOARD_HASH) {
771 const char *bios_ver = dmi_get_system_info(DMI_BIOS_VERSION);
772 if (strncmp(bios_ver, "1.0", 3) == 0) {
773 pr_info("gsmi: disabled on this board's BIOS %s\n",
774 bios_ver);
775 return -ENODEV;
776 }
777 }
778
779 /* check for valid SMI command port in ACPI FADT */
780 if (acpi_gbl_FADT.smi_command == 0) {
781 pr_info("gsmi: missing smi_command\n");
782 return -ENODEV;
783 }
784
785 /* Test the smihandler with a bogus command. If it leaves the
786 * calling argument in %ax untouched, there is no handler for
787 * GSMI commands.
788 */
789 cmd = GSMI_CALLBACK | GSMI_CMD_RESERVED << 8;
790 asm volatile (
791 "outb %%al, %%dx\n\t"
792 : "=a" (result)
793 : "0" (cmd),
794 "d" (acpi_gbl_FADT.smi_command)
795 : "memory", "cc"
796 );
797 if (cmd == result) {
798 pr_info("gsmi: no gsmi handler in firmware\n");
799 return -ENODEV;
800 }
801
802 /* Found */
803 return 0;
804 }
805
806 static struct kobject *gsmi_kobj;
807
808 static const struct platform_device_info gsmi_dev_info = {
809 .name = "gsmi",
810 .id = -1,
811 /* SMI callbacks require 32bit addresses */
812 .dma_mask = DMA_BIT_MASK(32),
813 };
814
815 #ifdef CONFIG_PM
gsmi_log_s0ix_info(u8 cmd)816 static void gsmi_log_s0ix_info(u8 cmd)
817 {
818 unsigned long flags;
819
820 /*
821 * If platform has not enabled S0ix logging, then no action is
822 * necessary.
823 */
824 if (!s0ix_logging_enable)
825 return;
826
827 spin_lock_irqsave(&gsmi_dev.lock, flags);
828
829 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
830
831 gsmi_exec(GSMI_CALLBACK, cmd);
832
833 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
834 }
835
gsmi_log_s0ix_suspend(struct device * dev)836 static int gsmi_log_s0ix_suspend(struct device *dev)
837 {
838 /*
839 * If system is not suspending via firmware using the standard ACPI Sx
840 * types, then make a GSMI call to log the suspend info.
841 */
842 if (!pm_suspend_via_firmware())
843 gsmi_log_s0ix_info(GSMI_CMD_LOG_S0IX_SUSPEND);
844
845 /*
846 * Always return success, since we do not want suspend
847 * to fail just because of logging failure.
848 */
849 return 0;
850 }
851
gsmi_log_s0ix_resume(struct device * dev)852 static int gsmi_log_s0ix_resume(struct device *dev)
853 {
854 /*
855 * If system did not resume via firmware, then make a GSMI call to log
856 * the resume info and wake source.
857 */
858 if (!pm_resume_via_firmware())
859 gsmi_log_s0ix_info(GSMI_CMD_LOG_S0IX_RESUME);
860
861 /*
862 * Always return success, since we do not want resume
863 * to fail just because of logging failure.
864 */
865 return 0;
866 }
867
868 static const struct dev_pm_ops gsmi_pm_ops = {
869 .suspend_noirq = gsmi_log_s0ix_suspend,
870 .resume_noirq = gsmi_log_s0ix_resume,
871 };
872
gsmi_platform_driver_probe(struct platform_device * dev)873 static int gsmi_platform_driver_probe(struct platform_device *dev)
874 {
875 return 0;
876 }
877
878 static struct platform_driver gsmi_driver_info = {
879 .driver = {
880 .name = "gsmi",
881 .pm = &gsmi_pm_ops,
882 },
883 .probe = gsmi_platform_driver_probe,
884 };
885 #endif
886
gsmi_init(void)887 static __init int gsmi_init(void)
888 {
889 unsigned long flags;
890 int ret;
891
892 ret = gsmi_system_valid();
893 if (ret)
894 return ret;
895
896 gsmi_dev.smi_cmd = acpi_gbl_FADT.smi_command;
897
898 #ifdef CONFIG_PM
899 ret = platform_driver_register(&gsmi_driver_info);
900 if (unlikely(ret)) {
901 printk(KERN_ERR "gsmi: unable to register platform driver\n");
902 return ret;
903 }
904 #endif
905
906 /* register device */
907 gsmi_dev.pdev = platform_device_register_full(&gsmi_dev_info);
908 if (IS_ERR(gsmi_dev.pdev)) {
909 printk(KERN_ERR "gsmi: unable to register platform device\n");
910 return PTR_ERR(gsmi_dev.pdev);
911 }
912
913 /* SMI access needs to be serialized */
914 spin_lock_init(&gsmi_dev.lock);
915
916 ret = -ENOMEM;
917
918 /*
919 * SLAB cache is created using SLAB_CACHE_DMA32 to ensure that the
920 * allocations for gsmi_buf come from the DMA32 memory zone. These
921 * buffers have nothing to do with DMA. They are required for
922 * communication with firmware executing in SMI mode which can only
923 * access the bottom 4GiB of physical memory. Since DMA32 memory zone
924 * guarantees allocation under the 4GiB boundary, this driver creates
925 * a SLAB cache with SLAB_CACHE_DMA32 flag.
926 */
927 gsmi_dev.mem_pool = kmem_cache_create("gsmi", GSMI_BUF_SIZE,
928 GSMI_BUF_ALIGN,
929 SLAB_CACHE_DMA32, NULL);
930 if (!gsmi_dev.mem_pool)
931 goto out_err;
932
933 /*
934 * pre-allocate buffers because sometimes we are called when
935 * this is not feasible: oops, panic, die, mce, etc
936 */
937 gsmi_dev.name_buf = gsmi_buf_alloc();
938 if (!gsmi_dev.name_buf) {
939 printk(KERN_ERR "gsmi: failed to allocate name buffer\n");
940 goto out_err;
941 }
942
943 gsmi_dev.data_buf = gsmi_buf_alloc();
944 if (!gsmi_dev.data_buf) {
945 printk(KERN_ERR "gsmi: failed to allocate data buffer\n");
946 goto out_err;
947 }
948
949 gsmi_dev.param_buf = gsmi_buf_alloc();
950 if (!gsmi_dev.param_buf) {
951 printk(KERN_ERR "gsmi: failed to allocate param buffer\n");
952 goto out_err;
953 }
954
955 /*
956 * Determine type of handshake used to serialize the SMI
957 * entry. See also gsmi_exec().
958 *
959 * There's a "behavior" present on some chipsets where writing the
960 * SMI trigger register in the southbridge doesn't result in an
961 * immediate SMI. Rather, the processor can execute "a few" more
962 * instructions before the SMI takes effect. To ensure synchronous
963 * behavior, implement a handshake between the kernel driver and the
964 * firmware handler to spin until released. This ioctl determines
965 * the type of handshake.
966 *
967 * NONE: The firmware handler does not implement any
968 * handshake. Either it doesn't need to, or it's legacy firmware
969 * that doesn't know it needs to and never will.
970 *
971 * CF: The firmware handler will clear the CF in the saved
972 * state before returning. The driver may set the CF and test for
973 * it to clear before proceeding.
974 *
975 * SPIN: The firmware handler does not implement any handshake
976 * but the driver should spin for a hundred or so microseconds
977 * to ensure the SMI has triggered.
978 *
979 * Finally, the handler will return -ENOSYS if
980 * GSMI_CMD_HANDSHAKE_TYPE is unimplemented, which implies
981 * HANDSHAKE_NONE.
982 */
983 spin_lock_irqsave(&gsmi_dev.lock, flags);
984 gsmi_dev.handshake_type = GSMI_HANDSHAKE_SPIN;
985 gsmi_dev.handshake_type =
986 gsmi_exec(GSMI_CALLBACK, GSMI_CMD_HANDSHAKE_TYPE);
987 if (gsmi_dev.handshake_type == -ENOSYS)
988 gsmi_dev.handshake_type = GSMI_HANDSHAKE_NONE;
989 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
990
991 /* Remove and clean up gsmi if the handshake could not complete. */
992 if (gsmi_dev.handshake_type == -ENXIO) {
993 printk(KERN_INFO "gsmi version " DRIVER_VERSION
994 " failed to load\n");
995 ret = -ENODEV;
996 goto out_err;
997 }
998
999 /* Register in the firmware directory */
1000 ret = -ENOMEM;
1001 gsmi_kobj = kobject_create_and_add("gsmi", firmware_kobj);
1002 if (!gsmi_kobj) {
1003 printk(KERN_INFO "gsmi: Failed to create firmware kobj\n");
1004 goto out_err;
1005 }
1006
1007 /* Setup eventlog access */
1008 ret = sysfs_create_bin_file(gsmi_kobj, &eventlog_bin_attr);
1009 if (ret) {
1010 printk(KERN_INFO "gsmi: Failed to setup eventlog");
1011 goto out_err;
1012 }
1013
1014 /* Other attributes */
1015 ret = sysfs_create_files(gsmi_kobj, gsmi_attrs);
1016 if (ret) {
1017 printk(KERN_INFO "gsmi: Failed to add attrs");
1018 goto out_remove_bin_file;
1019 }
1020
1021 #ifdef CONFIG_EFI
1022 ret = efivars_register(&efivars, &efivar_ops, gsmi_kobj);
1023 if (ret) {
1024 printk(KERN_INFO "gsmi: Failed to register efivars\n");
1025 sysfs_remove_files(gsmi_kobj, gsmi_attrs);
1026 goto out_remove_bin_file;
1027 }
1028 #endif
1029
1030 register_reboot_notifier(&gsmi_reboot_notifier);
1031 register_die_notifier(&gsmi_die_notifier);
1032 atomic_notifier_chain_register(&panic_notifier_list,
1033 &gsmi_panic_notifier);
1034
1035 printk(KERN_INFO "gsmi version " DRIVER_VERSION " loaded\n");
1036
1037 return 0;
1038
1039 out_remove_bin_file:
1040 sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr);
1041 out_err:
1042 kobject_put(gsmi_kobj);
1043 gsmi_buf_free(gsmi_dev.param_buf);
1044 gsmi_buf_free(gsmi_dev.data_buf);
1045 gsmi_buf_free(gsmi_dev.name_buf);
1046 kmem_cache_destroy(gsmi_dev.mem_pool);
1047 platform_device_unregister(gsmi_dev.pdev);
1048 pr_info("gsmi: failed to load: %d\n", ret);
1049 #ifdef CONFIG_PM
1050 platform_driver_unregister(&gsmi_driver_info);
1051 #endif
1052 return ret;
1053 }
1054
gsmi_exit(void)1055 static void __exit gsmi_exit(void)
1056 {
1057 unregister_reboot_notifier(&gsmi_reboot_notifier);
1058 unregister_die_notifier(&gsmi_die_notifier);
1059 atomic_notifier_chain_unregister(&panic_notifier_list,
1060 &gsmi_panic_notifier);
1061 #ifdef CONFIG_EFI
1062 efivars_unregister(&efivars);
1063 #endif
1064
1065 sysfs_remove_files(gsmi_kobj, gsmi_attrs);
1066 sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr);
1067 kobject_put(gsmi_kobj);
1068 gsmi_buf_free(gsmi_dev.param_buf);
1069 gsmi_buf_free(gsmi_dev.data_buf);
1070 gsmi_buf_free(gsmi_dev.name_buf);
1071 kmem_cache_destroy(gsmi_dev.mem_pool);
1072 platform_device_unregister(gsmi_dev.pdev);
1073 #ifdef CONFIG_PM
1074 platform_driver_unregister(&gsmi_driver_info);
1075 #endif
1076 }
1077
1078 module_init(gsmi_init);
1079 module_exit(gsmi_exit);
1080
1081 MODULE_AUTHOR("Google, Inc.");
1082 MODULE_LICENSE("GPL");
1083