1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * bioscalls.c - the lowlevel layer of the PnPBIOS driver
4  */
5 
6 #include <linux/types.h>
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/linkage.h>
10 #include <linux/kernel.h>
11 #include <linux/device.h>
12 #include <linux/pnp.h>
13 #include <linux/mm.h>
14 #include <linux/smp.h>
15 #include <linux/kmod.h>
16 #include <linux/completion.h>
17 #include <linux/spinlock.h>
18 
19 #include <asm/page.h>
20 #include <asm/desc.h>
21 #include <asm/byteorder.h>
22 
23 #include "pnpbios.h"
24 
25 __visible struct {
26 	u16 offset;
27 	u16 segment;
28 } pnp_bios_callpoint;
29 
30 /*
31  * These are some opcodes for a "static asmlinkage"
32  * As this code is *not* executed inside the linux kernel segment, but in a
33  * alias at offset 0, we need a far return that can not be compiled by
34  * default (please, prove me wrong! this is *really* ugly!)
35  * This is the only way to get the bios to return into the kernel code,
36  * because the bios code runs in 16 bit protected mode and therefore can only
37  * return to the caller if the call is within the first 64kB, and the linux
38  * kernel begins at offset 3GB...
39  */
40 
41 asmlinkage __visible void pnp_bios_callfunc(void);
42 
43 __asm__(".text			\n"
44 	__ALIGN_STR "\n"
45 	".globl pnp_bios_callfunc\n"
46 	"pnp_bios_callfunc:\n"
47 	"	pushl %edx	\n"
48 	"	pushl %ecx	\n"
49 	"	pushl %ebx	\n"
50 	"	pushl %eax	\n"
51 	"	lcallw *pnp_bios_callpoint\n"
52 	"	addl $16, %esp	\n"
53 	"	lret		\n"
54 	".previous		\n");
55 
56 #define Q2_SET_SEL(cpu, selname, address, size) \
57 do { \
58 	struct desc_struct *gdt = get_cpu_gdt_rw((cpu)); \
59 	set_desc_base(&gdt[(selname) >> 3], (u32)(address)); \
60 	set_desc_limit(&gdt[(selname) >> 3], (size) - 1); \
61 } while(0)
62 
63 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
64 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
65 
66 /*
67  * At some point we want to use this stack frame pointer to unwind
68  * after PnP BIOS oopses.
69  */
70 
71 __visible u32 pnp_bios_fault_esp;
72 __visible u32 pnp_bios_fault_eip;
73 __visible u32 pnp_bios_is_utter_crap = 0;
74 
75 static DEFINE_SPINLOCK(pnp_bios_lock);
76 
77 /*
78  * Support Functions
79  */
80 
call_pnp_bios(u16 func,u16 arg1,u16 arg2,u16 arg3,u16 arg4,u16 arg5,u16 arg6,u16 arg7,void * ts1_base,u32 ts1_size,void * ts2_base,u32 ts2_size)81 static inline u16 call_pnp_bios(u16 func, u16 arg1, u16 arg2, u16 arg3,
82 				u16 arg4, u16 arg5, u16 arg6, u16 arg7,
83 				void *ts1_base, u32 ts1_size,
84 				void *ts2_base, u32 ts2_size)
85 {
86 	unsigned long flags;
87 	u16 status;
88 	struct desc_struct save_desc_40;
89 	int cpu;
90 
91 	/*
92 	 * PnP BIOSes are generally not terribly re-entrant.
93 	 * Also, don't rely on them to save everything correctly.
94 	 */
95 	if (pnp_bios_is_utter_crap)
96 		return PNP_FUNCTION_NOT_SUPPORTED;
97 
98 	cpu = get_cpu();
99 	save_desc_40 = get_cpu_gdt_rw(cpu)[0x40 / 8];
100 	get_cpu_gdt_rw(cpu)[0x40 / 8] = bad_bios_desc;
101 
102 	/* On some boxes IRQ's during PnP BIOS calls are deadly.  */
103 	spin_lock_irqsave(&pnp_bios_lock, flags);
104 
105 	/* The lock prevents us bouncing CPU here */
106 	if (ts1_size)
107 		Q2_SET_SEL(smp_processor_id(), PNP_TS1, ts1_base, ts1_size);
108 	if (ts2_size)
109 		Q2_SET_SEL(smp_processor_id(), PNP_TS2, ts2_base, ts2_size);
110 
111 	__asm__ __volatile__("pushl %%ebp\n\t"
112 			     "pushl %%edi\n\t"
113 			     "pushl %%esi\n\t"
114 			     "pushl %%ds\n\t"
115 			     "pushl %%es\n\t"
116 			     "pushl %%fs\n\t"
117 			     "pushl %%gs\n\t"
118 			     "pushfl\n\t"
119 			     "movl %%esp, pnp_bios_fault_esp\n\t"
120 			     "movl $1f, pnp_bios_fault_eip\n\t"
121 			     "lcall %5,%6\n\t"
122 			     "1:popfl\n\t"
123 			     "popl %%gs\n\t"
124 			     "popl %%fs\n\t"
125 			     "popl %%es\n\t"
126 			     "popl %%ds\n\t"
127 			     "popl %%esi\n\t"
128 			     "popl %%edi\n\t"
129 			     "popl %%ebp\n\t":"=a"(status)
130 			     :"0"((func) | (((u32) arg1) << 16)),
131 			     "b"((arg2) | (((u32) arg3) << 16)),
132 			     "c"((arg4) | (((u32) arg5) << 16)),
133 			     "d"((arg6) | (((u32) arg7) << 16)),
134 			     "i"(PNP_CS32), "i"(0)
135 			     :"memory");
136 	spin_unlock_irqrestore(&pnp_bios_lock, flags);
137 
138 	get_cpu_gdt_rw(cpu)[0x40 / 8] = save_desc_40;
139 	put_cpu();
140 
141 	/* If we get here and this is set then the PnP BIOS faulted on us. */
142 	if (pnp_bios_is_utter_crap) {
143 		printk(KERN_ERR
144 		       "PnPBIOS: Warning! Your PnP BIOS caused a fatal error. Attempting to continue\n");
145 		printk(KERN_ERR
146 		       "PnPBIOS: You may need to reboot with the \"pnpbios=off\" option to operate stably\n");
147 		printk(KERN_ERR
148 		       "PnPBIOS: Check with your vendor for an updated BIOS\n");
149 	}
150 
151 	return status;
152 }
153 
pnpbios_print_status(const char * module,u16 status)154 void pnpbios_print_status(const char *module, u16 status)
155 {
156 	switch (status) {
157 	case PNP_SUCCESS:
158 		printk(KERN_ERR "PnPBIOS: %s: function successful\n", module);
159 		break;
160 	case PNP_NOT_SET_STATICALLY:
161 		printk(KERN_ERR "PnPBIOS: %s: unable to set static resources\n",
162 		       module);
163 		break;
164 	case PNP_UNKNOWN_FUNCTION:
165 		printk(KERN_ERR "PnPBIOS: %s: invalid function number passed\n",
166 		       module);
167 		break;
168 	case PNP_FUNCTION_NOT_SUPPORTED:
169 		printk(KERN_ERR
170 		       "PnPBIOS: %s: function not supported on this system\n",
171 		       module);
172 		break;
173 	case PNP_INVALID_HANDLE:
174 		printk(KERN_ERR "PnPBIOS: %s: invalid handle\n", module);
175 		break;
176 	case PNP_BAD_PARAMETER:
177 		printk(KERN_ERR "PnPBIOS: %s: invalid parameters were passed\n",
178 		       module);
179 		break;
180 	case PNP_SET_FAILED:
181 		printk(KERN_ERR "PnPBIOS: %s: unable to set resources\n",
182 		       module);
183 		break;
184 	case PNP_EVENTS_NOT_PENDING:
185 		printk(KERN_ERR "PnPBIOS: %s: no events are pending\n", module);
186 		break;
187 	case PNP_SYSTEM_NOT_DOCKED:
188 		printk(KERN_ERR "PnPBIOS: %s: the system is not docked\n",
189 		       module);
190 		break;
191 	case PNP_NO_ISA_PNP_CARDS:
192 		printk(KERN_ERR
193 		       "PnPBIOS: %s: no isapnp cards are installed on this system\n",
194 		       module);
195 		break;
196 	case PNP_UNABLE_TO_DETERMINE_DOCK_CAPABILITIES:
197 		printk(KERN_ERR
198 		       "PnPBIOS: %s: cannot determine the capabilities of the docking station\n",
199 		       module);
200 		break;
201 	case PNP_CONFIG_CHANGE_FAILED_NO_BATTERY:
202 		printk(KERN_ERR
203 		       "PnPBIOS: %s: unable to undock, the system does not have a battery\n",
204 		       module);
205 		break;
206 	case PNP_CONFIG_CHANGE_FAILED_RESOURCE_CONFLICT:
207 		printk(KERN_ERR
208 		       "PnPBIOS: %s: could not dock due to resource conflicts\n",
209 		       module);
210 		break;
211 	case PNP_BUFFER_TOO_SMALL:
212 		printk(KERN_ERR "PnPBIOS: %s: the buffer passed is too small\n",
213 		       module);
214 		break;
215 	case PNP_USE_ESCD_SUPPORT:
216 		printk(KERN_ERR "PnPBIOS: %s: use ESCD instead\n", module);
217 		break;
218 	case PNP_MESSAGE_NOT_SUPPORTED:
219 		printk(KERN_ERR "PnPBIOS: %s: the message is unsupported\n",
220 		       module);
221 		break;
222 	case PNP_HARDWARE_ERROR:
223 		printk(KERN_ERR "PnPBIOS: %s: a hardware failure has occurred\n",
224 		       module);
225 		break;
226 	default:
227 		printk(KERN_ERR "PnPBIOS: %s: unexpected status 0x%x\n", module,
228 		       status);
229 		break;
230 	}
231 }
232 
233 /*
234  * PnP BIOS Low Level Calls
235  */
236 
237 #define PNP_GET_NUM_SYS_DEV_NODES		0x00
238 #define PNP_GET_SYS_DEV_NODE			0x01
239 #define PNP_SET_SYS_DEV_NODE			0x02
240 #define PNP_GET_EVENT				0x03
241 #define PNP_SEND_MESSAGE			0x04
242 #define PNP_GET_DOCKING_STATION_INFORMATION	0x05
243 #define PNP_SET_STATIC_ALLOCED_RES_INFO		0x09
244 #define PNP_GET_STATIC_ALLOCED_RES_INFO		0x0a
245 #define PNP_GET_APM_ID_TABLE			0x0b
246 #define PNP_GET_PNP_ISA_CONFIG_STRUC		0x40
247 #define PNP_GET_ESCD_INFO			0x41
248 #define PNP_READ_ESCD				0x42
249 #define PNP_WRITE_ESCD				0x43
250 
251 /*
252  * Call PnP BIOS with function 0x00, "get number of system device nodes"
253  */
__pnp_bios_dev_node_info(struct pnp_dev_node_info * data)254 static int __pnp_bios_dev_node_info(struct pnp_dev_node_info *data)
255 {
256 	u16 status;
257 
258 	if (!pnp_bios_present())
259 		return PNP_FUNCTION_NOT_SUPPORTED;
260 	status = call_pnp_bios(PNP_GET_NUM_SYS_DEV_NODES, 0, PNP_TS1, 2,
261 			       PNP_TS1, PNP_DS, 0, 0, data,
262 			       sizeof(struct pnp_dev_node_info), NULL, 0);
263 	data->no_nodes &= 0xff;
264 	return status;
265 }
266 
pnp_bios_dev_node_info(struct pnp_dev_node_info * data)267 int pnp_bios_dev_node_info(struct pnp_dev_node_info *data)
268 {
269 	int status = __pnp_bios_dev_node_info(data);
270 
271 	if (status)
272 		pnpbios_print_status("dev_node_info", status);
273 	return status;
274 }
275 
276 /*
277  * Note that some PnP BIOSes (e.g., on Sony Vaio laptops) die a horrible
278  * death if they are asked to access the "current" configuration.
279  * Therefore, if it's a matter of indifference, it's better to call
280  * get_dev_node() and set_dev_node() with boot=1 rather than with boot=0.
281  */
282 
283 /*
284  * Call PnP BIOS with function 0x01, "get system device node"
285  * Input: *nodenum = desired node,
286  *        boot = whether to get nonvolatile boot (!=0)
287  *               or volatile current (0) config
288  * Output: *nodenum=next node or 0xff if no more nodes
289  */
__pnp_bios_get_dev_node(u8 * nodenum,char boot,struct pnp_bios_node * data)290 static int __pnp_bios_get_dev_node(u8 *nodenum, char boot,
291 				   struct pnp_bios_node *data)
292 {
293 	u16 status;
294 	u16 tmp_nodenum;
295 
296 	if (!pnp_bios_present())
297 		return PNP_FUNCTION_NOT_SUPPORTED;
298 	if (!boot && pnpbios_dont_use_current_config)
299 		return PNP_FUNCTION_NOT_SUPPORTED;
300 	tmp_nodenum = *nodenum;
301 	status = call_pnp_bios(PNP_GET_SYS_DEV_NODE, 0, PNP_TS1, 0, PNP_TS2,
302 			       boot ? 2 : 1, PNP_DS, 0, &tmp_nodenum,
303 			       sizeof(tmp_nodenum), data, 65536);
304 	*nodenum = tmp_nodenum;
305 	return status;
306 }
307 
pnp_bios_get_dev_node(u8 * nodenum,char boot,struct pnp_bios_node * data)308 int pnp_bios_get_dev_node(u8 *nodenum, char boot, struct pnp_bios_node *data)
309 {
310 	int status;
311 
312 	status = __pnp_bios_get_dev_node(nodenum, boot, data);
313 	if (status)
314 		pnpbios_print_status("get_dev_node", status);
315 	return status;
316 }
317 
318 /*
319  * Call PnP BIOS with function 0x02, "set system device node"
320  * Input: *nodenum = desired node,
321  *        boot = whether to set nonvolatile boot (!=0)
322  *               or volatile current (0) config
323  */
__pnp_bios_set_dev_node(u8 nodenum,char boot,struct pnp_bios_node * data)324 static int __pnp_bios_set_dev_node(u8 nodenum, char boot,
325 				   struct pnp_bios_node *data)
326 {
327 	u16 status;
328 
329 	if (!pnp_bios_present())
330 		return PNP_FUNCTION_NOT_SUPPORTED;
331 	if (!boot && pnpbios_dont_use_current_config)
332 		return PNP_FUNCTION_NOT_SUPPORTED;
333 	status = call_pnp_bios(PNP_SET_SYS_DEV_NODE, nodenum, 0, PNP_TS1,
334 			       boot ? 2 : 1, PNP_DS, 0, 0, data, 65536, NULL,
335 			       0);
336 	return status;
337 }
338 
pnp_bios_set_dev_node(u8 nodenum,char boot,struct pnp_bios_node * data)339 int pnp_bios_set_dev_node(u8 nodenum, char boot, struct pnp_bios_node *data)
340 {
341 	int status;
342 
343 	status = __pnp_bios_set_dev_node(nodenum, boot, data);
344 	if (status) {
345 		pnpbios_print_status("set_dev_node", status);
346 		return status;
347 	}
348 	if (!boot) {		/* Update devlist */
349 		status = pnp_bios_get_dev_node(&nodenum, boot, data);
350 		if (status)
351 			return status;
352 	}
353 	return status;
354 }
355 
356 /*
357  * Call PnP BIOS with function 0x05, "get docking station information"
358  */
pnp_bios_dock_station_info(struct pnp_docking_station_info * data)359 int pnp_bios_dock_station_info(struct pnp_docking_station_info *data)
360 {
361 	u16 status;
362 
363 	if (!pnp_bios_present())
364 		return PNP_FUNCTION_NOT_SUPPORTED;
365 	status = call_pnp_bios(PNP_GET_DOCKING_STATION_INFORMATION, 0, PNP_TS1,
366 			       PNP_DS, 0, 0, 0, 0, data,
367 			       sizeof(struct pnp_docking_station_info), NULL,
368 			       0);
369 	return status;
370 }
371 
372 /*
373  * Call PnP BIOS with function 0x0a, "get statically allocated resource
374  * information"
375  */
__pnp_bios_get_stat_res(char * info)376 static int __pnp_bios_get_stat_res(char *info)
377 {
378 	u16 status;
379 
380 	if (!pnp_bios_present())
381 		return PNP_FUNCTION_NOT_SUPPORTED;
382 	status = call_pnp_bios(PNP_GET_STATIC_ALLOCED_RES_INFO, 0, PNP_TS1,
383 			       PNP_DS, 0, 0, 0, 0, info, 65536, NULL, 0);
384 	return status;
385 }
386 
pnp_bios_get_stat_res(char * info)387 int pnp_bios_get_stat_res(char *info)
388 {
389 	int status;
390 
391 	status = __pnp_bios_get_stat_res(info);
392 	if (status)
393 		pnpbios_print_status("get_stat_res", status);
394 	return status;
395 }
396 
397 /*
398  * Call PnP BIOS with function 0x40, "get isa pnp configuration structure"
399  */
__pnp_bios_isapnp_config(struct pnp_isa_config_struc * data)400 static int __pnp_bios_isapnp_config(struct pnp_isa_config_struc *data)
401 {
402 	u16 status;
403 
404 	if (!pnp_bios_present())
405 		return PNP_FUNCTION_NOT_SUPPORTED;
406 	status = call_pnp_bios(PNP_GET_PNP_ISA_CONFIG_STRUC, 0, PNP_TS1, PNP_DS,
407 			       0, 0, 0, 0, data,
408 			       sizeof(struct pnp_isa_config_struc), NULL, 0);
409 	return status;
410 }
411 
pnp_bios_isapnp_config(struct pnp_isa_config_struc * data)412 int pnp_bios_isapnp_config(struct pnp_isa_config_struc *data)
413 {
414 	int status;
415 
416 	status = __pnp_bios_isapnp_config(data);
417 	if (status)
418 		pnpbios_print_status("isapnp_config", status);
419 	return status;
420 }
421 
422 /*
423  * Call PnP BIOS with function 0x41, "get ESCD info"
424  */
__pnp_bios_escd_info(struct escd_info_struc * data)425 static int __pnp_bios_escd_info(struct escd_info_struc *data)
426 {
427 	u16 status;
428 
429 	if (!pnp_bios_present())
430 		return ESCD_FUNCTION_NOT_SUPPORTED;
431 	status = call_pnp_bios(PNP_GET_ESCD_INFO, 0, PNP_TS1, 2, PNP_TS1, 4,
432 			       PNP_TS1, PNP_DS, data,
433 			       sizeof(struct escd_info_struc), NULL, 0);
434 	return status;
435 }
436 
pnp_bios_escd_info(struct escd_info_struc * data)437 int pnp_bios_escd_info(struct escd_info_struc *data)
438 {
439 	int status;
440 
441 	status = __pnp_bios_escd_info(data);
442 	if (status)
443 		pnpbios_print_status("escd_info", status);
444 	return status;
445 }
446 
447 /*
448  * Call PnP BIOS function 0x42, "read ESCD"
449  * nvram_base is determined by calling escd_info
450  */
__pnp_bios_read_escd(char * data,u32 nvram_base)451 static int __pnp_bios_read_escd(char *data, u32 nvram_base)
452 {
453 	u16 status;
454 
455 	if (!pnp_bios_present())
456 		return ESCD_FUNCTION_NOT_SUPPORTED;
457 	status = call_pnp_bios(PNP_READ_ESCD, 0, PNP_TS1, PNP_TS2, PNP_DS, 0, 0,
458 			       0, data, 65536, __va(nvram_base), 65536);
459 	return status;
460 }
461 
pnp_bios_read_escd(char * data,u32 nvram_base)462 int pnp_bios_read_escd(char *data, u32 nvram_base)
463 {
464 	int status;
465 
466 	status = __pnp_bios_read_escd(data, nvram_base);
467 	if (status)
468 		pnpbios_print_status("read_escd", status);
469 	return status;
470 }
471 
pnpbios_calls_init(union pnp_bios_install_struct * header)472 void pnpbios_calls_init(union pnp_bios_install_struct *header)
473 {
474 	int i;
475 
476 	pnp_bios_callpoint.offset = header->fields.pm16offset;
477 	pnp_bios_callpoint.segment = PNP_CS16;
478 
479 	for_each_possible_cpu(i) {
480 		struct desc_struct *gdt = get_cpu_gdt_rw(i);
481 		if (!gdt)
482 			continue;
483 		set_desc_base(&gdt[GDT_ENTRY_PNPBIOS_CS32],
484 			 (unsigned long)&pnp_bios_callfunc);
485 		set_desc_base(&gdt[GDT_ENTRY_PNPBIOS_CS16],
486 			 (unsigned long)__va(header->fields.pm16cseg));
487 		set_desc_base(&gdt[GDT_ENTRY_PNPBIOS_DS],
488 			 (unsigned long)__va(header->fields.pm16dseg));
489 	}
490 }
491