2 * Copyright (c) 1997 Michael Smith
3 * Copyright (c) 1998 Jonathan Lemon
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * $FreeBSD: src/sys/i386/i386/bios.c,v 1.29.2.3 2001/07/19 18:07:35 imp Exp $
28 * $DragonFly: src/sys/platform/pc32/i386/bios.c,v 1.11 2006/09/03 17:43:59 dillon Exp $
32 * Code for dealing with the BIOS in x86 PC systems.
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
40 #include <machine/md_var.h>
41 #include <machine/globaldata.h>
42 #include <machine/pc/bios.h>
44 #define BIOS_START 0xe0000
45 #define BIOS_SIZE 0x20000
47 /* exported lookup results */
48 struct bios32_SDentry PCIbios;
49 struct PnPBIOS_table *PnPBIOStable;
51 static u_int bios32_SDCI;
53 /* start fairly early */
54 static void bios32_init(void *junk);
55 SYSINIT(bios32, SI_SUB_CPU, SI_ORDER_ANY, bios32_init, NULL);
60 * Locate various bios32 entities.
63 bios32_init(void *junk)
66 struct bios32_SDheader *sdh;
67 struct PnPBIOS_table *pt;
73 * BIOS32 Service Directory, PCI BIOS
76 /* look for the signature */
77 if ((sigaddr = bios_sigsearch(0, "_32_", 4, 16, 0)) != 0) {
79 /* get a virtual pointer to the structure */
80 sdh = (struct bios32_SDheader *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
81 for (cv = (uint8_t *)sdh, ck = 0, i = 0; i < (sdh->len * 16); i++) {
84 /* If checksum is OK, enable use of the entrypoint */
85 if ((ck == 0) && BIOS_START <= sdh->entry &&
86 (sdh->entry < (BIOS_START + BIOS_SIZE))
88 bios32_SDCI = BIOS_PADDRTOVADDR(sdh->entry);
90 printf("bios32: Found BIOS32 Service Directory header at %p\n", sdh);
91 printf("bios32: Entry = 0x%x (%x) Rev = %d Len = %d\n",
92 sdh->entry, bios32_SDCI, sdh->revision, sdh->len);
95 /* Allow user override of PCI BIOS search */
96 if (((p = kgetenv("machdep.bios.pci")) == NULL) || strcmp(p, "disable")) {
97 /* See if there's a PCI BIOS entrypoint here */
98 PCIbios.ident.id = 0x49435024; /* PCI systems should have this */
99 if (!bios32_SDlookup(&PCIbios) && bootverbose)
100 printf("pcibios: PCI BIOS entry at 0x%x\n", PCIbios.entry);
105 printf("bios32: Bad BIOS32 Service Directory\n");
112 * Allow user override of PnP BIOS search
114 if (((p = kgetenv("machdep.bios.pnp")) == NULL || strcmp(p, "disable")) &&
115 (sigaddr = bios_sigsearch(0, "$PnP", 4, 16, 0)) != 0
117 /* get a virtual pointer to the structure */
118 pt = (struct PnPBIOS_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
119 for (cv = (uint8_t *)pt, ck = 0, i = 0; i < pt->len; i++) {
122 /* If checksum is OK, enable use of the entrypoint */
126 printf("pnpbios: Found PnP BIOS data at %p\n", pt);
127 printf("pnpbios: Entry = %x:%x Rev = %d.%d\n",
128 pt->pmentrybase, pt->pmentryoffset, pt->version >> 4, pt->version & 0xf);
129 if ((pt->control & 0x3) == 0x01)
130 printf("pnpbios: Event flag at %x\n", pt->evflagaddr);
131 if (pt->oemdevid != 0)
132 printf("pnpbios: OEM ID %x\n", pt->oemdevid);
136 printf("pnpbios: Bad PnP BIOS data checksum\n");
142 /* look for other know signatures */
143 printf("Other BIOS signatures found:\n");
150 * Query the BIOS32 Service Directory for the service named in (ent),
151 * returns nonzero if the lookup fails. The caller must fill in
152 * (ent->ident), the remainder are populated on a successful lookup.
155 bios32_SDlookup(struct bios32_SDentry *ent)
157 struct bios_regs args;
159 if (bios32_SDCI == 0)
162 args.eax = ent->ident.id; /* set up arguments */
163 args.ebx = args.ecx = args.edx = 0;
164 bios32(&args, bios32_SDCI, GSEL(GCODE_SEL, SEL_KPL));
165 if ((args.eax & 0xff) == 0) { /* success? */
166 ent->base = args.ebx;
168 ent->entry = args.edx;
169 ent->ventry = BIOS_PADDRTOVADDR(ent->base + ent->entry);
170 return (0); /* all OK */
172 return (1); /* failed */
179 * Search some or all of the BIOS region for a signature string.
181 * (start) Optional offset returned from this function
182 * (for searching for multiple matches), or NULL
183 * to start the search from the base of the BIOS.
184 * Note that this will be a _physical_ address in
185 * the range 0xe0000 - 0xfffff.
186 * (sig) is a pointer to the byte(s) of the signature.
187 * (siglen) number of bytes in the signature.
188 * (paralen) signature paragraph (alignment) size.
189 * (sigofs) offset of the signature within the paragraph.
191 * Returns the _physical_ address of the found signature, 0 if the
192 * signature was not found.
196 bios_sigsearch(uint32_t start, u_char *sig, int siglen, int paralen, int sigofs)
200 /* compute the starting address */
201 if ((start >= BIOS_START) && (start <= (BIOS_START + BIOS_SIZE))) {
202 sp = (char *)BIOS_PADDRTOVADDR(start);
203 } else if (start == 0) {
204 sp = (char *)BIOS_PADDRTOVADDR(BIOS_START);
206 return 0; /* bogus start address */
209 /* compute the end address */
210 end = (u_char *)BIOS_PADDRTOVADDR(BIOS_START + BIOS_SIZE);
213 while ((sp + sigofs + siglen) < end) {
216 if (!bcmp(sp + sigofs, sig, siglen)) {
217 /* convert back to physical address */
218 return((uint32_t)BIOS_VADDRTOPADDR(sp));
226 * do not staticize, used by bioscall.s
237 } bioscall_vector; /* bios jump vector */
240 set_bios_selectors(struct bios_segments *seg, int flags)
242 struct soft_segment_descriptor ssd = {
243 0, /* segment base address (overwritten) */
244 0, /* length (overwritten) */
245 SDT_MEMERA, /* segment type (overwritten) */
246 0, /* priority level */
247 1, /* descriptor present */
249 1, /* descriptor size (overwritten) */
250 0 /* granularity == byte units */
252 union descriptor *p_gdt;
254 p_gdt = &gdt[mycpu->gd_cpuid * NGDT];
256 ssd.ssd_base = seg->code32.base;
257 ssd.ssd_limit = seg->code32.limit;
258 ssdtosd(&ssd, &p_gdt[GBIOSCODE32_SEL].sd);
261 if (flags & BIOSCODE_FLAG) {
262 ssd.ssd_base = seg->code16.base;
263 ssd.ssd_limit = seg->code16.limit;
264 ssdtosd(&ssd, &p_gdt[GBIOSCODE16_SEL].sd);
267 ssd.ssd_type = SDT_MEMRWA;
268 if (flags & BIOSDATA_FLAG) {
269 ssd.ssd_base = seg->data.base;
270 ssd.ssd_limit = seg->data.limit;
271 ssdtosd(&ssd, &p_gdt[GBIOSDATA_SEL].sd);
274 if (flags & BIOSUTIL_FLAG) {
275 ssd.ssd_base = seg->util.base;
276 ssd.ssd_limit = seg->util.limit;
277 ssdtosd(&ssd, &p_gdt[GBIOSUTIL_SEL].sd);
280 if (flags & BIOSARGS_FLAG) {
281 ssd.ssd_base = seg->args.base;
282 ssd.ssd_limit = seg->args.limit;
283 ssdtosd(&ssd, &p_gdt[GBIOSARGS_SEL].sd);
288 extern void bios16_jmp(void);
291 * this routine is really greedy with selectors, and uses 5:
293 * 32-bit code selector: to return to kernel
294 * 16-bit code selector: for running code
295 * data selector: for 16-bit data
296 * util selector: extra utility selector
297 * args selector: to handle pointers
299 * the util selector is set from the util16 entry in bios16_args, if a
300 * "U" specifier is seen.
302 * See <machine/pc/bios.h> for description of format specifiers
305 bios16(struct bios_args *args, char *fmt, ...)
307 char *p, *stack, *stack_top;
309 int flags = BIOSCODE_FLAG | BIOSDATA_FLAG;
310 u_int i, arg_start, arg_end;
314 arg_start = 0xffffffff;
318 * Some BIOS entrypoints attempt to copy the largest-case
319 * argument frame (in order to generalise handling for
320 * different entry types). If our argument frame is
321 * smaller than this, the BIOS will reach off the top of
322 * our constructed stack segment. Pad the top of the stack
323 * with some garbage to avoid this.
325 stack = (caddr_t)PAGE_SIZE - 32;
328 for (p = fmt; p && *p; p++) {
330 case 'p': /* 32-bit pointer */
331 i = __va_arg(ap, u_int);
332 arg_start = min(arg_start, i);
333 arg_end = max(arg_end, i);
334 flags |= BIOSARGS_FLAG;
338 case 'i': /* 32-bit integer */
339 i = __va_arg(ap, u_int);
343 case 'U': /* 16-bit selector */
344 flags |= BIOSUTIL_FLAG;
346 case 'D': /* 16-bit selector */
347 case 'C': /* 16-bit selector */
351 case 's': /* 16-bit integer passed as an int */
352 i = __va_arg(ap, int);
361 if (flags & BIOSARGS_FLAG) {
362 if (arg_end - arg_start > ctob(16))
364 args->seg.args.base = arg_start;
365 args->seg.args.limit = 0xffff;
368 args->seg.code32.base = (u_int)&bios16_jmp & PG_FRAME;
369 args->seg.code32.limit = 0xffff;
371 ptd = (pd_entry_t *)rcr3();
372 if ((pd_entry_t)ptd == IdlePTD) {
374 * no page table, so create one and install it.
376 pte = malloc(PAGE_SIZE, M_TEMP, M_WAITOK|M_ZERO);
377 ptd = (pd_entry_t *)((vm_offset_t)ptd + KERNBASE);
378 *ptd = vtophys(pte) | PG_RW | PG_V;
381 * this is a user-level page table
386 * install pointer to page 0. Flush the tlb for safety. We don't
387 * migrate between cpus so a local flush is sufficient.
389 *pte = (vm86pa - PAGE_SIZE) | PG_RW | PG_V;
394 for (p = fmt; p && *p; p++) {
396 case 'p': /* 32-bit pointer */
397 i = __va_arg(ap, u_int);
398 *(u_int *)stack = (i - arg_start) |
399 (GSEL(GBIOSARGS_SEL, SEL_KPL) << 16);
403 case 'i': /* 32-bit integer */
404 i = __va_arg(ap, u_int);
409 case 'U': /* 16-bit selector */
410 *(u_short *)stack = GSEL(GBIOSUTIL_SEL, SEL_KPL);
414 case 'D': /* 16-bit selector */
415 *(u_short *)stack = GSEL(GBIOSDATA_SEL, SEL_KPL);
419 case 'C': /* 16-bit selector */
420 *(u_short *)stack = GSEL(GBIOSCODE16_SEL, SEL_KPL);
424 case 's': /* 16-bit integer passed as an int */
425 i = __va_arg(ap, int);
426 *(u_short *)stack = i;
435 set_bios_selectors(&args->seg, flags);
436 bioscall_vector.vec16.offset = (u_short)args->entry;
437 bioscall_vector.vec16.segment = GSEL(GBIOSCODE16_SEL, SEL_KPL);
439 i = bios16_call(&args->r, stack_top);
442 *pte = 0; /* remove entry */
444 *ptd = 0; /* remove page table */
445 free(pte, M_TEMP); /* ... and free it */
448 * XXX only needs to be invlpg(0) but that doesn't work on the 386