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/panic_notifier.h>
23 #include <linux/ioctl.h>
24 #include <linux/acpi.h>
25 #include <linux/io.h>
26 #include <linux/uaccess.h>
27 #include <linux/dmi.h>
28 #include <linux/kdebug.h>
29 #include <linux/reboot.h>
30 #include <linux/efi.h>
31 #include <linux/module.h>
32 #include <linux/ucs2_string.h>
33 #include <linux/suspend.h>
34
35 #define GSMI_SHUTDOWN_CLEAN 0 /* Clean Shutdown */
36 /* TODO(mikew@google.com): Tie in HARDLOCKUP_DETECTOR with NMIWDT */
37 #define GSMI_SHUTDOWN_NMIWDT 1 /* NMI Watchdog */
38 #define GSMI_SHUTDOWN_PANIC 2 /* Panic */
39 #define GSMI_SHUTDOWN_OOPS 3 /* Oops */
40 #define GSMI_SHUTDOWN_DIE 4 /* Die -- No longer meaningful */
41 #define GSMI_SHUTDOWN_MCE 5 /* Machine Check */
42 #define GSMI_SHUTDOWN_SOFTWDT 6 /* Software Watchdog */
43 #define GSMI_SHUTDOWN_MBE 7 /* Uncorrected ECC */
44 #define GSMI_SHUTDOWN_TRIPLE 8 /* Triple Fault */
45
46 #define DRIVER_VERSION "1.0"
47 #define GSMI_GUID_SIZE 16
48 #define GSMI_BUF_SIZE 1024
49 #define GSMI_BUF_ALIGN sizeof(u64)
50 #define GSMI_CALLBACK 0xef
51
52 /* SMI return codes */
53 #define GSMI_SUCCESS 0x00
54 #define GSMI_UNSUPPORTED2 0x03
55 #define GSMI_LOG_FULL 0x0b
56 #define GSMI_VAR_NOT_FOUND 0x0e
57 #define GSMI_HANDSHAKE_SPIN 0x7d
58 #define GSMI_HANDSHAKE_CF 0x7e
59 #define GSMI_HANDSHAKE_NONE 0x7f
60 #define GSMI_INVALID_PARAMETER 0x82
61 #define GSMI_UNSUPPORTED 0x83
62 #define GSMI_BUFFER_TOO_SMALL 0x85
63 #define GSMI_NOT_READY 0x86
64 #define GSMI_DEVICE_ERROR 0x87
65 #define GSMI_NOT_FOUND 0x8e
66
67 #define QUIRKY_BOARD_HASH 0x78a30a50
68
69 /* Internally used commands passed to the firmware */
70 #define GSMI_CMD_GET_NVRAM_VAR 0x01
71 #define GSMI_CMD_GET_NEXT_VAR 0x02
72 #define GSMI_CMD_SET_NVRAM_VAR 0x03
73 #define GSMI_CMD_SET_EVENT_LOG 0x08
74 #define GSMI_CMD_CLEAR_EVENT_LOG 0x09
75 #define GSMI_CMD_LOG_S0IX_SUSPEND 0x0a
76 #define GSMI_CMD_LOG_S0IX_RESUME 0x0b
77 #define GSMI_CMD_CLEAR_CONFIG 0x20
78 #define GSMI_CMD_HANDSHAKE_TYPE 0xC1
79 #define GSMI_CMD_RESERVED 0xff
80
81 /* Magic entry type for kernel events */
82 #define GSMI_LOG_ENTRY_TYPE_KERNEL 0xDEAD
83
84 /* SMI buffers must be in 32bit physical address space */
85 struct gsmi_buf {
86 u8 *start; /* start of buffer */
87 size_t length; /* length of buffer */
88 u32 address; /* physical address of buffer */
89 };
90
91 static struct gsmi_device {
92 struct platform_device *pdev; /* platform device */
93 struct gsmi_buf *name_buf; /* variable name buffer */
94 struct gsmi_buf *data_buf; /* generic data buffer */
95 struct gsmi_buf *param_buf; /* parameter buffer */
96 spinlock_t lock; /* serialize access to SMIs */
97 u16 smi_cmd; /* SMI command port */
98 int handshake_type; /* firmware handler interlock type */
99 struct kmem_cache *mem_pool; /* kmem cache for gsmi_buf allocations */
100 } gsmi_dev;
101
102 /* Packed structures for communicating with the firmware */
103 struct gsmi_nvram_var_param {
104 efi_guid_t guid;
105 u32 name_ptr;
106 u32 attributes;
107 u32 data_len;
108 u32 data_ptr;
109 } __packed;
110
111 struct gsmi_get_next_var_param {
112 u8 guid[GSMI_GUID_SIZE];
113 u32 name_ptr;
114 u32 name_len;
115 } __packed;
116
117 struct gsmi_set_eventlog_param {
118 u32 data_ptr;
119 u32 data_len;
120 u32 type;
121 } __packed;
122
123 /* Event log formats */
124 struct gsmi_log_entry_type_1 {
125 u16 type;
126 u32 instance;
127 } __packed;
128
129 /*
130 * Some platforms don't have explicit SMI handshake
131 * and need to wait for SMI to complete.
132 */
133 #define GSMI_DEFAULT_SPINCOUNT 0x10000
134 static unsigned int spincount = GSMI_DEFAULT_SPINCOUNT;
135 module_param(spincount, uint, 0600);
136 MODULE_PARM_DESC(spincount,
137 "The number of loop iterations to use when using the spin handshake.");
138
139 /*
140 * Some older platforms with Apollo Lake chipsets do not support S0ix logging
141 * in their GSMI handlers, and behaved poorly when resuming via power button
142 * press if the logging was attempted. Updated firmware with proper behavior
143 * has long since shipped, removing the need for this opt-in parameter. It
144 * now exists as an opt-out parameter for folks defiantly running old
145 * firmware, or unforeseen circumstances. After the change from opt-in to
146 * opt-out has baked sufficiently, this parameter should probably be removed
147 * entirely.
148 */
149 static bool s0ix_logging_enable = true;
150 module_param(s0ix_logging_enable, bool, 0600);
151
gsmi_buf_alloc(void)152 static struct gsmi_buf *gsmi_buf_alloc(void)
153 {
154 struct gsmi_buf *smibuf;
155
156 smibuf = kzalloc(sizeof(*smibuf), GFP_KERNEL);
157 if (!smibuf) {
158 printk(KERN_ERR "gsmi: out of memory\n");
159 return NULL;
160 }
161
162 /* allocate buffer in 32bit address space */
163 smibuf->start = kmem_cache_alloc(gsmi_dev.mem_pool, GFP_KERNEL);
164 if (!smibuf->start) {
165 printk(KERN_ERR "gsmi: failed to allocate name buffer\n");
166 kfree(smibuf);
167 return NULL;
168 }
169
170 /* fill in the buffer handle */
171 smibuf->length = GSMI_BUF_SIZE;
172 smibuf->address = (u32)virt_to_phys(smibuf->start);
173
174 return smibuf;
175 }
176
gsmi_buf_free(struct gsmi_buf * smibuf)177 static void gsmi_buf_free(struct gsmi_buf *smibuf)
178 {
179 if (smibuf) {
180 if (smibuf->start)
181 kmem_cache_free(gsmi_dev.mem_pool, smibuf->start);
182 kfree(smibuf);
183 }
184 }
185
186 /*
187 * Make a call to gsmi func(sub). GSMI error codes are translated to
188 * in-kernel errnos (0 on success, -ERRNO on error).
189 */
gsmi_exec(u8 func,u8 sub)190 static int gsmi_exec(u8 func, u8 sub)
191 {
192 u16 cmd = (sub << 8) | func;
193 u16 result = 0;
194 int rc = 0;
195
196 /*
197 * AH : Subfunction number
198 * AL : Function number
199 * EBX : Parameter block address
200 * DX : SMI command port
201 *
202 * Three protocols here. See also the comment in gsmi_init().
203 */
204 if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_CF) {
205 /*
206 * If handshake_type == HANDSHAKE_CF then set CF on the
207 * way in and wait for the handler to clear it; this avoids
208 * corrupting register state on those chipsets which have
209 * a delay between writing the SMI trigger register and
210 * entering SMM.
211 */
212 asm volatile (
213 "stc\n"
214 "outb %%al, %%dx\n"
215 "1: jc 1b\n"
216 : "=a" (result)
217 : "0" (cmd),
218 "d" (gsmi_dev.smi_cmd),
219 "b" (gsmi_dev.param_buf->address)
220 : "memory", "cc"
221 );
222 } else if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_SPIN) {
223 /*
224 * If handshake_type == HANDSHAKE_SPIN we spin a
225 * hundred-ish usecs to ensure the SMI has triggered.
226 */
227 asm volatile (
228 "outb %%al, %%dx\n"
229 "1: loop 1b\n"
230 : "=a" (result)
231 : "0" (cmd),
232 "d" (gsmi_dev.smi_cmd),
233 "b" (gsmi_dev.param_buf->address),
234 "c" (spincount)
235 : "memory", "cc"
236 );
237 } else {
238 /*
239 * If handshake_type == HANDSHAKE_NONE we do nothing;
240 * either we don't need to or it's legacy firmware that
241 * doesn't understand the CF protocol.
242 */
243 asm volatile (
244 "outb %%al, %%dx\n\t"
245 : "=a" (result)
246 : "0" (cmd),
247 "d" (gsmi_dev.smi_cmd),
248 "b" (gsmi_dev.param_buf->address)
249 : "memory", "cc"
250 );
251 }
252
253 /* check return code from SMI handler */
254 switch (result) {
255 case GSMI_SUCCESS:
256 break;
257 case GSMI_VAR_NOT_FOUND:
258 /* not really an error, but let the caller know */
259 rc = 1;
260 break;
261 case GSMI_INVALID_PARAMETER:
262 printk(KERN_ERR "gsmi: exec 0x%04x: Invalid parameter\n", cmd);
263 rc = -EINVAL;
264 break;
265 case GSMI_BUFFER_TOO_SMALL:
266 printk(KERN_ERR "gsmi: exec 0x%04x: Buffer too small\n", cmd);
267 rc = -ENOMEM;
268 break;
269 case GSMI_UNSUPPORTED:
270 case GSMI_UNSUPPORTED2:
271 if (sub != GSMI_CMD_HANDSHAKE_TYPE)
272 printk(KERN_ERR "gsmi: exec 0x%04x: Not supported\n",
273 cmd);
274 rc = -ENOSYS;
275 break;
276 case GSMI_NOT_READY:
277 printk(KERN_ERR "gsmi: exec 0x%04x: Not ready\n", cmd);
278 rc = -EBUSY;
279 break;
280 case GSMI_DEVICE_ERROR:
281 printk(KERN_ERR "gsmi: exec 0x%04x: Device error\n", cmd);
282 rc = -EFAULT;
283 break;
284 case GSMI_NOT_FOUND:
285 printk(KERN_ERR "gsmi: exec 0x%04x: Data not found\n", cmd);
286 rc = -ENOENT;
287 break;
288 case GSMI_LOG_FULL:
289 printk(KERN_ERR "gsmi: exec 0x%04x: Log full\n", cmd);
290 rc = -ENOSPC;
291 break;
292 case GSMI_HANDSHAKE_CF:
293 case GSMI_HANDSHAKE_SPIN:
294 case GSMI_HANDSHAKE_NONE:
295 rc = result;
296 break;
297 default:
298 printk(KERN_ERR "gsmi: exec 0x%04x: Unknown error 0x%04x\n",
299 cmd, result);
300 rc = -ENXIO;
301 }
302
303 return rc;
304 }
305
306 #ifdef CONFIG_EFI
307
308 static struct efivars efivars;
309
gsmi_get_variable(efi_char16_t * name,efi_guid_t * vendor,u32 * attr,unsigned long * data_size,void * data)310 static efi_status_t gsmi_get_variable(efi_char16_t *name,
311 efi_guid_t *vendor, u32 *attr,
312 unsigned long *data_size,
313 void *data)
314 {
315 struct gsmi_nvram_var_param param = {
316 .name_ptr = gsmi_dev.name_buf->address,
317 .data_ptr = gsmi_dev.data_buf->address,
318 .data_len = (u32)*data_size,
319 };
320 efi_status_t ret = EFI_SUCCESS;
321 unsigned long flags;
322 size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2);
323 int rc;
324
325 if (name_len >= GSMI_BUF_SIZE / 2)
326 return EFI_BAD_BUFFER_SIZE;
327
328 spin_lock_irqsave(&gsmi_dev.lock, flags);
329
330 /* Vendor guid */
331 memcpy(¶m.guid, vendor, sizeof(param.guid));
332
333 /* variable name, already in UTF-16 */
334 memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length);
335 memcpy(gsmi_dev.name_buf->start, name, name_len * 2);
336
337 /* data pointer */
338 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
339
340 /* parameter buffer */
341 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
342 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
343
344 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NVRAM_VAR);
345 if (rc < 0) {
346 printk(KERN_ERR "gsmi: Get Variable failed\n");
347 ret = EFI_LOAD_ERROR;
348 } else if (rc == 1) {
349 /* variable was not found */
350 ret = EFI_NOT_FOUND;
351 } else {
352 /* Get the arguments back */
353 memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param));
354
355 /* The size reported is the min of all of our buffers */
356 *data_size = min_t(unsigned long, *data_size,
357 gsmi_dev.data_buf->length);
358 *data_size = min_t(unsigned long, *data_size, param.data_len);
359
360 /* Copy data back to return buffer. */
361 memcpy(data, gsmi_dev.data_buf->start, *data_size);
362
363 /* All variables are have the following attributes */
364 *attr = EFI_VARIABLE_NON_VOLATILE |
365 EFI_VARIABLE_BOOTSERVICE_ACCESS |
366 EFI_VARIABLE_RUNTIME_ACCESS;
367 }
368
369 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
370
371 return ret;
372 }
373
gsmi_get_next_variable(unsigned long * name_size,efi_char16_t * name,efi_guid_t * vendor)374 static efi_status_t gsmi_get_next_variable(unsigned long *name_size,
375 efi_char16_t *name,
376 efi_guid_t *vendor)
377 {
378 struct gsmi_get_next_var_param param = {
379 .name_ptr = gsmi_dev.name_buf->address,
380 .name_len = gsmi_dev.name_buf->length,
381 };
382 efi_status_t ret = EFI_SUCCESS;
383 int rc;
384 unsigned long flags;
385
386 /* For the moment, only support buffers that exactly match in size */
387 if (*name_size != GSMI_BUF_SIZE)
388 return EFI_BAD_BUFFER_SIZE;
389
390 /* Let's make sure the thing is at least null-terminated */
391 if (ucs2_strnlen(name, GSMI_BUF_SIZE / 2) == GSMI_BUF_SIZE / 2)
392 return EFI_INVALID_PARAMETER;
393
394 spin_lock_irqsave(&gsmi_dev.lock, flags);
395
396 /* guid */
397 memcpy(¶m.guid, vendor, sizeof(param.guid));
398
399 /* variable name, already in UTF-16 */
400 memcpy(gsmi_dev.name_buf->start, name, *name_size);
401
402 /* parameter buffer */
403 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
404 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
405
406 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NEXT_VAR);
407 if (rc < 0) {
408 printk(KERN_ERR "gsmi: Get Next Variable Name failed\n");
409 ret = EFI_LOAD_ERROR;
410 } else if (rc == 1) {
411 /* variable not found -- end of list */
412 ret = EFI_NOT_FOUND;
413 } else {
414 /* copy variable data back to return buffer */
415 memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param));
416
417 /* Copy the name back */
418 memcpy(name, gsmi_dev.name_buf->start, GSMI_BUF_SIZE);
419 *name_size = ucs2_strnlen(name, GSMI_BUF_SIZE / 2) * 2;
420
421 /* copy guid to return buffer */
422 memcpy(vendor, ¶m.guid, sizeof(param.guid));
423 ret = EFI_SUCCESS;
424 }
425
426 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
427
428 return ret;
429 }
430
gsmi_set_variable(efi_char16_t * name,efi_guid_t * vendor,u32 attr,unsigned long data_size,void * data)431 static efi_status_t gsmi_set_variable(efi_char16_t *name,
432 efi_guid_t *vendor,
433 u32 attr,
434 unsigned long data_size,
435 void *data)
436 {
437 struct gsmi_nvram_var_param param = {
438 .name_ptr = gsmi_dev.name_buf->address,
439 .data_ptr = gsmi_dev.data_buf->address,
440 .data_len = (u32)data_size,
441 .attributes = EFI_VARIABLE_NON_VOLATILE |
442 EFI_VARIABLE_BOOTSERVICE_ACCESS |
443 EFI_VARIABLE_RUNTIME_ACCESS,
444 };
445 size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2);
446 efi_status_t ret = EFI_SUCCESS;
447 int rc;
448 unsigned long flags;
449
450 if (name_len >= GSMI_BUF_SIZE / 2)
451 return EFI_BAD_BUFFER_SIZE;
452
453 spin_lock_irqsave(&gsmi_dev.lock, flags);
454
455 /* guid */
456 memcpy(¶m.guid, vendor, sizeof(param.guid));
457
458 /* variable name, already in UTF-16 */
459 memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length);
460 memcpy(gsmi_dev.name_buf->start, name, name_len * 2);
461
462 /* data pointer */
463 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
464 memcpy(gsmi_dev.data_buf->start, data, data_size);
465
466 /* parameter buffer */
467 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
468 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
469
470 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_NVRAM_VAR);
471 if (rc < 0) {
472 printk(KERN_ERR "gsmi: Set Variable failed\n");
473 ret = EFI_INVALID_PARAMETER;
474 }
475
476 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
477
478 return ret;
479 }
480
481 static const struct efivar_operations efivar_ops = {
482 .get_variable = gsmi_get_variable,
483 .set_variable = gsmi_set_variable,
484 .get_next_variable = gsmi_get_next_variable,
485 };
486
487 #endif /* CONFIG_EFI */
488
eventlog_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t count)489 static ssize_t eventlog_write(struct file *filp, struct kobject *kobj,
490 struct bin_attribute *bin_attr,
491 char *buf, loff_t pos, size_t count)
492 {
493 struct gsmi_set_eventlog_param param = {
494 .data_ptr = gsmi_dev.data_buf->address,
495 };
496 int rc = 0;
497 unsigned long flags;
498
499 /* Pull the type out */
500 if (count < sizeof(u32))
501 return -EINVAL;
502 param.type = *(u32 *)buf;
503 buf += sizeof(u32);
504
505 /* The remaining buffer is the data payload */
506 if ((count - sizeof(u32)) > gsmi_dev.data_buf->length)
507 return -EINVAL;
508 param.data_len = count - sizeof(u32);
509
510 spin_lock_irqsave(&gsmi_dev.lock, flags);
511
512 /* data pointer */
513 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
514 memcpy(gsmi_dev.data_buf->start, buf, param.data_len);
515
516 /* parameter buffer */
517 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
518 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
519
520 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG);
521 if (rc < 0)
522 printk(KERN_ERR "gsmi: Set Event Log failed\n");
523
524 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
525
526 return (rc == 0) ? count : rc;
527
528 }
529
530 static struct bin_attribute eventlog_bin_attr = {
531 .attr = {.name = "append_to_eventlog", .mode = 0200},
532 .write = eventlog_write,
533 };
534
gsmi_clear_eventlog_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)535 static ssize_t gsmi_clear_eventlog_store(struct kobject *kobj,
536 struct kobj_attribute *attr,
537 const char *buf, size_t count)
538 {
539 int rc;
540 unsigned long flags;
541 unsigned long val;
542 struct {
543 u32 percentage;
544 u32 data_type;
545 } param;
546
547 rc = kstrtoul(buf, 0, &val);
548 if (rc)
549 return rc;
550
551 /*
552 * Value entered is a percentage, 0 through 100, anything else
553 * is invalid.
554 */
555 if (val > 100)
556 return -EINVAL;
557
558 /* data_type here selects the smbios event log. */
559 param.percentage = val;
560 param.data_type = 0;
561
562 spin_lock_irqsave(&gsmi_dev.lock, flags);
563
564 /* parameter buffer */
565 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
566 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
567
568 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_EVENT_LOG);
569
570 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
571
572 if (rc)
573 return rc;
574 return count;
575 }
576
577 static struct kobj_attribute gsmi_clear_eventlog_attr = {
578 .attr = {.name = "clear_eventlog", .mode = 0200},
579 .store = gsmi_clear_eventlog_store,
580 };
581
gsmi_clear_config_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)582 static ssize_t gsmi_clear_config_store(struct kobject *kobj,
583 struct kobj_attribute *attr,
584 const char *buf, size_t count)
585 {
586 int rc;
587 unsigned long flags;
588
589 spin_lock_irqsave(&gsmi_dev.lock, flags);
590
591 /* clear parameter buffer */
592 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
593
594 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_CONFIG);
595
596 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
597
598 if (rc)
599 return rc;
600 return count;
601 }
602
603 static struct kobj_attribute gsmi_clear_config_attr = {
604 .attr = {.name = "clear_config", .mode = 0200},
605 .store = gsmi_clear_config_store,
606 };
607
608 static const struct attribute *gsmi_attrs[] = {
609 &gsmi_clear_config_attr.attr,
610 &gsmi_clear_eventlog_attr.attr,
611 NULL,
612 };
613
gsmi_shutdown_reason(int reason)614 static int gsmi_shutdown_reason(int reason)
615 {
616 struct gsmi_log_entry_type_1 entry = {
617 .type = GSMI_LOG_ENTRY_TYPE_KERNEL,
618 .instance = reason,
619 };
620 struct gsmi_set_eventlog_param param = {
621 .data_len = sizeof(entry),
622 .type = 1,
623 };
624 static int saved_reason;
625 int rc = 0;
626 unsigned long flags;
627
628 /* avoid duplicate entries in the log */
629 if (saved_reason & (1 << reason))
630 return 0;
631
632 spin_lock_irqsave(&gsmi_dev.lock, flags);
633
634 saved_reason |= (1 << reason);
635
636 /* data pointer */
637 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
638 memcpy(gsmi_dev.data_buf->start, &entry, sizeof(entry));
639
640 /* parameter buffer */
641 param.data_ptr = gsmi_dev.data_buf->address;
642 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
643 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
644
645 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG);
646
647 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
648
649 if (rc < 0)
650 printk(KERN_ERR "gsmi: Log Shutdown Reason failed\n");
651 else
652 printk(KERN_EMERG "gsmi: Log Shutdown Reason 0x%02x\n",
653 reason);
654
655 return rc;
656 }
657
gsmi_reboot_callback(struct notifier_block * nb,unsigned long reason,void * arg)658 static int gsmi_reboot_callback(struct notifier_block *nb,
659 unsigned long reason, void *arg)
660 {
661 gsmi_shutdown_reason(GSMI_SHUTDOWN_CLEAN);
662 return NOTIFY_DONE;
663 }
664
665 static struct notifier_block gsmi_reboot_notifier = {
666 .notifier_call = gsmi_reboot_callback
667 };
668
gsmi_die_callback(struct notifier_block * nb,unsigned long reason,void * arg)669 static int gsmi_die_callback(struct notifier_block *nb,
670 unsigned long reason, void *arg)
671 {
672 if (reason == DIE_OOPS)
673 gsmi_shutdown_reason(GSMI_SHUTDOWN_OOPS);
674 return NOTIFY_DONE;
675 }
676
677 static struct notifier_block gsmi_die_notifier = {
678 .notifier_call = gsmi_die_callback
679 };
680
gsmi_panic_callback(struct notifier_block * nb,unsigned long reason,void * arg)681 static int gsmi_panic_callback(struct notifier_block *nb,
682 unsigned long reason, void *arg)
683 {
684
685 /*
686 * Panic callbacks are executed with all other CPUs stopped,
687 * so we must not attempt to spin waiting for gsmi_dev.lock
688 * to be released.
689 */
690 if (spin_is_locked(&gsmi_dev.lock))
691 return NOTIFY_DONE;
692
693 gsmi_shutdown_reason(GSMI_SHUTDOWN_PANIC);
694 return NOTIFY_DONE;
695 }
696
697 static struct notifier_block gsmi_panic_notifier = {
698 .notifier_call = gsmi_panic_callback,
699 };
700
701 /*
702 * This hash function was blatantly copied from include/linux/hash.h.
703 * It is used by this driver to obfuscate a board name that requires a
704 * quirk within this driver.
705 *
706 * Please do not remove this copy of the function as any changes to the
707 * global utility hash_64() function would break this driver's ability
708 * to identify a board and provide the appropriate quirk -- mikew@google.com
709 */
local_hash_64(u64 val,unsigned bits)710 static u64 __init local_hash_64(u64 val, unsigned bits)
711 {
712 u64 hash = val;
713
714 /* Sigh, gcc can't optimise this alone like it does for 32 bits. */
715 u64 n = hash;
716 n <<= 18;
717 hash -= n;
718 n <<= 33;
719 hash -= n;
720 n <<= 3;
721 hash += n;
722 n <<= 3;
723 hash -= n;
724 n <<= 4;
725 hash += n;
726 n <<= 2;
727 hash += n;
728
729 /* High bits are more random, so use them. */
730 return hash >> (64 - bits);
731 }
732
hash_oem_table_id(char s[8])733 static u32 __init hash_oem_table_id(char s[8])
734 {
735 u64 input;
736 memcpy(&input, s, 8);
737 return local_hash_64(input, 32);
738 }
739
740 static const struct dmi_system_id gsmi_dmi_table[] __initconst = {
741 {
742 .ident = "Google Board",
743 .matches = {
744 DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."),
745 },
746 },
747 {
748 .ident = "Coreboot Firmware",
749 .matches = {
750 DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
751 },
752 },
753 {}
754 };
755 MODULE_DEVICE_TABLE(dmi, gsmi_dmi_table);
756
gsmi_system_valid(void)757 static __init int gsmi_system_valid(void)
758 {
759 u32 hash;
760 u16 cmd, result;
761
762 if (!dmi_check_system(gsmi_dmi_table))
763 return -ENODEV;
764
765 /*
766 * Only newer firmware supports the gsmi interface. All older
767 * firmware that didn't support this interface used to plug the
768 * table name in the first four bytes of the oem_table_id field.
769 * Newer firmware doesn't do that though, so use that as the
770 * discriminant factor. We have to do this in order to
771 * whitewash our board names out of the public driver.
772 */
773 if (!strncmp(acpi_gbl_FADT.header.oem_table_id, "FACP", 4)) {
774 printk(KERN_INFO "gsmi: Board is too old\n");
775 return -ENODEV;
776 }
777
778 /* Disable on board with 1.0 BIOS due to Google bug 2602657 */
779 hash = hash_oem_table_id(acpi_gbl_FADT.header.oem_table_id);
780 if (hash == QUIRKY_BOARD_HASH) {
781 const char *bios_ver = dmi_get_system_info(DMI_BIOS_VERSION);
782 if (strncmp(bios_ver, "1.0", 3) == 0) {
783 pr_info("gsmi: disabled on this board's BIOS %s\n",
784 bios_ver);
785 return -ENODEV;
786 }
787 }
788
789 /* check for valid SMI command port in ACPI FADT */
790 if (acpi_gbl_FADT.smi_command == 0) {
791 pr_info("gsmi: missing smi_command\n");
792 return -ENODEV;
793 }
794
795 /* Test the smihandler with a bogus command. If it leaves the
796 * calling argument in %ax untouched, there is no handler for
797 * GSMI commands.
798 */
799 cmd = GSMI_CALLBACK | GSMI_CMD_RESERVED << 8;
800 asm volatile (
801 "outb %%al, %%dx\n\t"
802 : "=a" (result)
803 : "0" (cmd),
804 "d" (acpi_gbl_FADT.smi_command)
805 : "memory", "cc"
806 );
807 if (cmd == result) {
808 pr_info("gsmi: no gsmi handler in firmware\n");
809 return -ENODEV;
810 }
811
812 /* Found */
813 return 0;
814 }
815
816 static struct kobject *gsmi_kobj;
817
818 static const struct platform_device_info gsmi_dev_info = {
819 .name = "gsmi",
820 .id = -1,
821 /* SMI callbacks require 32bit addresses */
822 .dma_mask = DMA_BIT_MASK(32),
823 };
824
825 #ifdef CONFIG_PM
gsmi_log_s0ix_info(u8 cmd)826 static void gsmi_log_s0ix_info(u8 cmd)
827 {
828 unsigned long flags;
829
830 /*
831 * If platform has not enabled S0ix logging, then no action is
832 * necessary.
833 */
834 if (!s0ix_logging_enable)
835 return;
836
837 spin_lock_irqsave(&gsmi_dev.lock, flags);
838
839 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
840
841 gsmi_exec(GSMI_CALLBACK, cmd);
842
843 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
844 }
845
gsmi_log_s0ix_suspend(struct device * dev)846 static int gsmi_log_s0ix_suspend(struct device *dev)
847 {
848 /*
849 * If system is not suspending via firmware using the standard ACPI Sx
850 * types, then make a GSMI call to log the suspend info.
851 */
852 if (!pm_suspend_via_firmware())
853 gsmi_log_s0ix_info(GSMI_CMD_LOG_S0IX_SUSPEND);
854
855 /*
856 * Always return success, since we do not want suspend
857 * to fail just because of logging failure.
858 */
859 return 0;
860 }
861
gsmi_log_s0ix_resume(struct device * dev)862 static int gsmi_log_s0ix_resume(struct device *dev)
863 {
864 /*
865 * If system did not resume via firmware, then make a GSMI call to log
866 * the resume info and wake source.
867 */
868 if (!pm_resume_via_firmware())
869 gsmi_log_s0ix_info(GSMI_CMD_LOG_S0IX_RESUME);
870
871 /*
872 * Always return success, since we do not want resume
873 * to fail just because of logging failure.
874 */
875 return 0;
876 }
877
878 static const struct dev_pm_ops gsmi_pm_ops = {
879 .suspend_noirq = gsmi_log_s0ix_suspend,
880 .resume_noirq = gsmi_log_s0ix_resume,
881 };
882
gsmi_platform_driver_probe(struct platform_device * dev)883 static int gsmi_platform_driver_probe(struct platform_device *dev)
884 {
885 return 0;
886 }
887
888 static struct platform_driver gsmi_driver_info = {
889 .driver = {
890 .name = "gsmi",
891 .pm = &gsmi_pm_ops,
892 },
893 .probe = gsmi_platform_driver_probe,
894 };
895 #endif
896
gsmi_init(void)897 static __init int gsmi_init(void)
898 {
899 unsigned long flags;
900 int ret;
901
902 ret = gsmi_system_valid();
903 if (ret)
904 return ret;
905
906 gsmi_dev.smi_cmd = acpi_gbl_FADT.smi_command;
907
908 #ifdef CONFIG_PM
909 ret = platform_driver_register(&gsmi_driver_info);
910 if (unlikely(ret)) {
911 printk(KERN_ERR "gsmi: unable to register platform driver\n");
912 return ret;
913 }
914 #endif
915
916 /* register device */
917 gsmi_dev.pdev = platform_device_register_full(&gsmi_dev_info);
918 if (IS_ERR(gsmi_dev.pdev)) {
919 printk(KERN_ERR "gsmi: unable to register platform device\n");
920 return PTR_ERR(gsmi_dev.pdev);
921 }
922
923 /* SMI access needs to be serialized */
924 spin_lock_init(&gsmi_dev.lock);
925
926 ret = -ENOMEM;
927
928 /*
929 * SLAB cache is created using SLAB_CACHE_DMA32 to ensure that the
930 * allocations for gsmi_buf come from the DMA32 memory zone. These
931 * buffers have nothing to do with DMA. They are required for
932 * communication with firmware executing in SMI mode which can only
933 * access the bottom 4GiB of physical memory. Since DMA32 memory zone
934 * guarantees allocation under the 4GiB boundary, this driver creates
935 * a SLAB cache with SLAB_CACHE_DMA32 flag.
936 */
937 gsmi_dev.mem_pool = kmem_cache_create("gsmi", GSMI_BUF_SIZE,
938 GSMI_BUF_ALIGN,
939 SLAB_CACHE_DMA32, NULL);
940 if (!gsmi_dev.mem_pool)
941 goto out_err;
942
943 /*
944 * pre-allocate buffers because sometimes we are called when
945 * this is not feasible: oops, panic, die, mce, etc
946 */
947 gsmi_dev.name_buf = gsmi_buf_alloc();
948 if (!gsmi_dev.name_buf) {
949 printk(KERN_ERR "gsmi: failed to allocate name buffer\n");
950 goto out_err;
951 }
952
953 gsmi_dev.data_buf = gsmi_buf_alloc();
954 if (!gsmi_dev.data_buf) {
955 printk(KERN_ERR "gsmi: failed to allocate data buffer\n");
956 goto out_err;
957 }
958
959 gsmi_dev.param_buf = gsmi_buf_alloc();
960 if (!gsmi_dev.param_buf) {
961 printk(KERN_ERR "gsmi: failed to allocate param buffer\n");
962 goto out_err;
963 }
964
965 /*
966 * Determine type of handshake used to serialize the SMI
967 * entry. See also gsmi_exec().
968 *
969 * There's a "behavior" present on some chipsets where writing the
970 * SMI trigger register in the southbridge doesn't result in an
971 * immediate SMI. Rather, the processor can execute "a few" more
972 * instructions before the SMI takes effect. To ensure synchronous
973 * behavior, implement a handshake between the kernel driver and the
974 * firmware handler to spin until released. This ioctl determines
975 * the type of handshake.
976 *
977 * NONE: The firmware handler does not implement any
978 * handshake. Either it doesn't need to, or it's legacy firmware
979 * that doesn't know it needs to and never will.
980 *
981 * CF: The firmware handler will clear the CF in the saved
982 * state before returning. The driver may set the CF and test for
983 * it to clear before proceeding.
984 *
985 * SPIN: The firmware handler does not implement any handshake
986 * but the driver should spin for a hundred or so microseconds
987 * to ensure the SMI has triggered.
988 *
989 * Finally, the handler will return -ENOSYS if
990 * GSMI_CMD_HANDSHAKE_TYPE is unimplemented, which implies
991 * HANDSHAKE_NONE.
992 */
993 spin_lock_irqsave(&gsmi_dev.lock, flags);
994 gsmi_dev.handshake_type = GSMI_HANDSHAKE_SPIN;
995 gsmi_dev.handshake_type =
996 gsmi_exec(GSMI_CALLBACK, GSMI_CMD_HANDSHAKE_TYPE);
997 if (gsmi_dev.handshake_type == -ENOSYS)
998 gsmi_dev.handshake_type = GSMI_HANDSHAKE_NONE;
999 spin_unlock_irqrestore(&gsmi_dev.lock, flags);
1000
1001 /* Remove and clean up gsmi if the handshake could not complete. */
1002 if (gsmi_dev.handshake_type == -ENXIO) {
1003 printk(KERN_INFO "gsmi version " DRIVER_VERSION
1004 " failed to load\n");
1005 ret = -ENODEV;
1006 goto out_err;
1007 }
1008
1009 /* Register in the firmware directory */
1010 ret = -ENOMEM;
1011 gsmi_kobj = kobject_create_and_add("gsmi", firmware_kobj);
1012 if (!gsmi_kobj) {
1013 printk(KERN_INFO "gsmi: Failed to create firmware kobj\n");
1014 goto out_err;
1015 }
1016
1017 /* Setup eventlog access */
1018 ret = sysfs_create_bin_file(gsmi_kobj, &eventlog_bin_attr);
1019 if (ret) {
1020 printk(KERN_INFO "gsmi: Failed to setup eventlog");
1021 goto out_err;
1022 }
1023
1024 /* Other attributes */
1025 ret = sysfs_create_files(gsmi_kobj, gsmi_attrs);
1026 if (ret) {
1027 printk(KERN_INFO "gsmi: Failed to add attrs");
1028 goto out_remove_bin_file;
1029 }
1030
1031 #ifdef CONFIG_EFI
1032 ret = efivars_register(&efivars, &efivar_ops, gsmi_kobj);
1033 if (ret) {
1034 printk(KERN_INFO "gsmi: Failed to register efivars\n");
1035 sysfs_remove_files(gsmi_kobj, gsmi_attrs);
1036 goto out_remove_bin_file;
1037 }
1038 #endif
1039
1040 register_reboot_notifier(&gsmi_reboot_notifier);
1041 register_die_notifier(&gsmi_die_notifier);
1042 atomic_notifier_chain_register(&panic_notifier_list,
1043 &gsmi_panic_notifier);
1044
1045 printk(KERN_INFO "gsmi version " DRIVER_VERSION " loaded\n");
1046
1047 return 0;
1048
1049 out_remove_bin_file:
1050 sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr);
1051 out_err:
1052 kobject_put(gsmi_kobj);
1053 gsmi_buf_free(gsmi_dev.param_buf);
1054 gsmi_buf_free(gsmi_dev.data_buf);
1055 gsmi_buf_free(gsmi_dev.name_buf);
1056 kmem_cache_destroy(gsmi_dev.mem_pool);
1057 platform_device_unregister(gsmi_dev.pdev);
1058 pr_info("gsmi: failed to load: %d\n", ret);
1059 #ifdef CONFIG_PM
1060 platform_driver_unregister(&gsmi_driver_info);
1061 #endif
1062 return ret;
1063 }
1064
gsmi_exit(void)1065 static void __exit gsmi_exit(void)
1066 {
1067 unregister_reboot_notifier(&gsmi_reboot_notifier);
1068 unregister_die_notifier(&gsmi_die_notifier);
1069 atomic_notifier_chain_unregister(&panic_notifier_list,
1070 &gsmi_panic_notifier);
1071 #ifdef CONFIG_EFI
1072 efivars_unregister(&efivars);
1073 #endif
1074
1075 sysfs_remove_files(gsmi_kobj, gsmi_attrs);
1076 sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr);
1077 kobject_put(gsmi_kobj);
1078 gsmi_buf_free(gsmi_dev.param_buf);
1079 gsmi_buf_free(gsmi_dev.data_buf);
1080 gsmi_buf_free(gsmi_dev.name_buf);
1081 kmem_cache_destroy(gsmi_dev.mem_pool);
1082 platform_device_unregister(gsmi_dev.pdev);
1083 #ifdef CONFIG_PM
1084 platform_driver_unregister(&gsmi_driver_info);
1085 #endif
1086 }
1087
1088 module_init(gsmi_init);
1089 module_exit(gsmi_exit);
1090
1091 MODULE_AUTHOR("Google, Inc.");
1092 MODULE_LICENSE("GPL");
1093
