xref: /openbmc/qemu/hw/i386/multiboot.c (revision dc5bd18f)
1 /*
2  * QEMU PC System Emulator
3  *
4  * Copyright (c) 2003-2004 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include "qemu/osdep.h"
26 #include "qemu/option.h"
27 #include "cpu.h"
28 #include "hw/hw.h"
29 #include "hw/nvram/fw_cfg.h"
30 #include "multiboot.h"
31 #include "hw/loader.h"
32 #include "elf.h"
33 #include "sysemu/sysemu.h"
34 
35 /* Show multiboot debug output */
36 //#define DEBUG_MULTIBOOT
37 
38 #ifdef DEBUG_MULTIBOOT
39 #define mb_debug(a...) fprintf(stderr, ## a)
40 #else
41 #define mb_debug(a...)
42 #endif
43 
44 #define MULTIBOOT_STRUCT_ADDR 0x9000
45 
46 #if MULTIBOOT_STRUCT_ADDR > 0xf0000
47 #error multiboot struct needs to fit in 16 bit real mode
48 #endif
49 
50 enum {
51     /* Multiboot info */
52     MBI_FLAGS       = 0,
53     MBI_MEM_LOWER   = 4,
54     MBI_MEM_UPPER   = 8,
55     MBI_BOOT_DEVICE = 12,
56     MBI_CMDLINE     = 16,
57     MBI_MODS_COUNT  = 20,
58     MBI_MODS_ADDR   = 24,
59     MBI_MMAP_ADDR   = 48,
60     MBI_BOOTLOADER  = 64,
61 
62     MBI_SIZE        = 88,
63 
64     /* Multiboot modules */
65     MB_MOD_START    = 0,
66     MB_MOD_END      = 4,
67     MB_MOD_CMDLINE  = 8,
68 
69     MB_MOD_SIZE     = 16,
70 
71     /* Region offsets */
72     ADDR_E820_MAP = MULTIBOOT_STRUCT_ADDR + 0,
73     ADDR_MBI      = ADDR_E820_MAP + 0x500,
74 
75     /* Multiboot flags */
76     MULTIBOOT_FLAGS_MEMORY      = 1 << 0,
77     MULTIBOOT_FLAGS_BOOT_DEVICE = 1 << 1,
78     MULTIBOOT_FLAGS_CMDLINE     = 1 << 2,
79     MULTIBOOT_FLAGS_MODULES     = 1 << 3,
80     MULTIBOOT_FLAGS_MMAP        = 1 << 6,
81     MULTIBOOT_FLAGS_BOOTLOADER  = 1 << 9,
82 };
83 
84 typedef struct {
85     /* buffer holding kernel, cmdlines and mb_infos */
86     void *mb_buf;
87     /* address in target */
88     hwaddr mb_buf_phys;
89     /* size of mb_buf in bytes */
90     unsigned mb_buf_size;
91     /* offset of mb-info's in bytes */
92     hwaddr offset_mbinfo;
93     /* offset in buffer for cmdlines in bytes */
94     hwaddr offset_cmdlines;
95     /* offset in buffer for bootloader name in bytes */
96     hwaddr offset_bootloader;
97     /* offset of modules in bytes */
98     hwaddr offset_mods;
99     /* available slots for mb modules infos */
100     int mb_mods_avail;
101     /* currently used slots of mb modules */
102     int mb_mods_count;
103 } MultibootState;
104 
105 const char *bootloader_name = "qemu";
106 
107 static uint32_t mb_add_cmdline(MultibootState *s, const char *cmdline)
108 {
109     hwaddr p = s->offset_cmdlines;
110     char *b = (char *)s->mb_buf + p;
111 
112     memcpy(b, cmdline, strlen(cmdline) + 1);
113     s->offset_cmdlines += strlen(b) + 1;
114     return s->mb_buf_phys + p;
115 }
116 
117 static uint32_t mb_add_bootloader(MultibootState *s, const char *bootloader)
118 {
119     hwaddr p = s->offset_bootloader;
120     char *b = (char *)s->mb_buf + p;
121 
122     memcpy(b, bootloader, strlen(bootloader) + 1);
123     s->offset_bootloader += strlen(b) + 1;
124     return s->mb_buf_phys + p;
125 }
126 
127 static void mb_add_mod(MultibootState *s,
128                        hwaddr start, hwaddr end,
129                        hwaddr cmdline_phys)
130 {
131     char *p;
132     assert(s->mb_mods_count < s->mb_mods_avail);
133 
134     p = (char *)s->mb_buf + s->offset_mbinfo + MB_MOD_SIZE * s->mb_mods_count;
135 
136     stl_p(p + MB_MOD_START,   start);
137     stl_p(p + MB_MOD_END,     end);
138     stl_p(p + MB_MOD_CMDLINE, cmdline_phys);
139 
140     mb_debug("mod%02d: "TARGET_FMT_plx" - "TARGET_FMT_plx"\n",
141              s->mb_mods_count, start, end);
142 
143     s->mb_mods_count++;
144 }
145 
146 int load_multiboot(FWCfgState *fw_cfg,
147                    FILE *f,
148                    const char *kernel_filename,
149                    const char *initrd_filename,
150                    const char *kernel_cmdline,
151                    int kernel_file_size,
152                    uint8_t *header)
153 {
154     int i, is_multiboot = 0;
155     uint32_t flags = 0;
156     uint32_t mh_entry_addr;
157     uint32_t mh_load_addr;
158     uint32_t mb_kernel_size;
159     MultibootState mbs;
160     uint8_t bootinfo[MBI_SIZE];
161     uint8_t *mb_bootinfo_data;
162     uint32_t cmdline_len;
163 
164     /* Ok, let's see if it is a multiboot image.
165        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
166     for (i = 0; i < (8192 - 48); i += 4) {
167         if (ldl_p(header+i) == 0x1BADB002) {
168             uint32_t checksum = ldl_p(header+i+8);
169             flags = ldl_p(header+i+4);
170             checksum += flags;
171             checksum += (uint32_t)0x1BADB002;
172             if (!checksum) {
173                 is_multiboot = 1;
174                 break;
175             }
176         }
177     }
178 
179     if (!is_multiboot)
180         return 0; /* no multiboot */
181 
182     mb_debug("qemu: I believe we found a multiboot image!\n");
183     memset(bootinfo, 0, sizeof(bootinfo));
184     memset(&mbs, 0, sizeof(mbs));
185 
186     if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
187         fprintf(stderr, "qemu: multiboot knows VBE. we don't.\n");
188     }
189     if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
190         uint64_t elf_entry;
191         uint64_t elf_low, elf_high;
192         int kernel_size;
193         fclose(f);
194 
195         if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
196             fprintf(stderr, "Cannot load x86-64 image, give a 32bit one.\n");
197             exit(1);
198         }
199 
200         kernel_size = load_elf(kernel_filename, NULL, NULL, &elf_entry,
201                                &elf_low, &elf_high, 0, I386_ELF_MACHINE,
202                                0, 0);
203         if (kernel_size < 0) {
204             fprintf(stderr, "Error while loading elf kernel\n");
205             exit(1);
206         }
207         mh_load_addr = elf_low;
208         mb_kernel_size = elf_high - elf_low;
209         mh_entry_addr = elf_entry;
210 
211         mbs.mb_buf = g_malloc(mb_kernel_size);
212         if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
213             fprintf(stderr, "Error while fetching elf kernel from rom\n");
214             exit(1);
215         }
216 
217         mb_debug("qemu: loading multiboot-elf kernel (%#x bytes) with entry %#zx\n",
218                   mb_kernel_size, (size_t)mh_entry_addr);
219     } else {
220         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
221         uint32_t mh_header_addr = ldl_p(header+i+12);
222         uint32_t mh_load_end_addr = ldl_p(header+i+20);
223         uint32_t mh_bss_end_addr = ldl_p(header+i+24);
224 
225         mh_load_addr = ldl_p(header+i+16);
226         if (mh_header_addr < mh_load_addr) {
227             fprintf(stderr, "invalid mh_load_addr address\n");
228             exit(1);
229         }
230 
231         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
232         uint32_t mb_load_size = 0;
233         mh_entry_addr = ldl_p(header+i+28);
234 
235         if (mh_load_end_addr) {
236             if (mh_bss_end_addr < mh_load_addr) {
237                 fprintf(stderr, "invalid mh_bss_end_addr address\n");
238                 exit(1);
239             }
240             mb_kernel_size = mh_bss_end_addr - mh_load_addr;
241 
242             if (mh_load_end_addr < mh_load_addr) {
243                 fprintf(stderr, "invalid mh_load_end_addr address\n");
244                 exit(1);
245             }
246             mb_load_size = mh_load_end_addr - mh_load_addr;
247         } else {
248             if (kernel_file_size < mb_kernel_text_offset) {
249                 fprintf(stderr, "invalid kernel_file_size\n");
250                 exit(1);
251             }
252             mb_kernel_size = kernel_file_size - mb_kernel_text_offset;
253             mb_load_size = mb_kernel_size;
254         }
255 
256         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.
257         uint32_t mh_mode_type = ldl_p(header+i+32);
258         uint32_t mh_width = ldl_p(header+i+36);
259         uint32_t mh_height = ldl_p(header+i+40);
260         uint32_t mh_depth = ldl_p(header+i+44); */
261 
262         mb_debug("multiboot: mh_header_addr = %#x\n", mh_header_addr);
263         mb_debug("multiboot: mh_load_addr = %#x\n", mh_load_addr);
264         mb_debug("multiboot: mh_load_end_addr = %#x\n", mh_load_end_addr);
265         mb_debug("multiboot: mh_bss_end_addr = %#x\n", mh_bss_end_addr);
266         mb_debug("qemu: loading multiboot kernel (%#x bytes) at %#x\n",
267                  mb_load_size, mh_load_addr);
268 
269         mbs.mb_buf = g_malloc(mb_kernel_size);
270         fseek(f, mb_kernel_text_offset, SEEK_SET);
271         if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
272             fprintf(stderr, "fread() failed\n");
273             exit(1);
274         }
275         memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
276         fclose(f);
277     }
278 
279     mbs.mb_buf_phys = mh_load_addr;
280 
281     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
282     mbs.offset_mbinfo = mbs.mb_buf_size;
283 
284     /* Calculate space for cmdlines, bootloader name, and mb_mods */
285     cmdline_len = strlen(kernel_filename) + 1;
286     cmdline_len += strlen(kernel_cmdline) + 1;
287     if (initrd_filename) {
288         const char *r = initrd_filename;
289         cmdline_len += strlen(r) + 1;
290         mbs.mb_mods_avail = 1;
291         while (*(r = get_opt_value(NULL, 0, r))) {
292            mbs.mb_mods_avail++;
293            r++;
294         }
295     }
296 
297     mbs.mb_buf_size += cmdline_len;
298     mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
299     mbs.mb_buf_size += strlen(bootloader_name) + 1;
300 
301     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
302 
303     /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
304     mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
305     mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
306     mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
307 
308     if (initrd_filename) {
309         const char *next_initrd;
310         char not_last, tmpbuf[strlen(initrd_filename) + 1];
311 
312         mbs.offset_mods = mbs.mb_buf_size;
313 
314         do {
315             char *next_space;
316             int mb_mod_length;
317             uint32_t offs = mbs.mb_buf_size;
318 
319             next_initrd = get_opt_value(tmpbuf, sizeof(tmpbuf), initrd_filename);
320             not_last = *next_initrd;
321             /* if a space comes after the module filename, treat everything
322                after that as parameters */
323             hwaddr c = mb_add_cmdline(&mbs, tmpbuf);
324             if ((next_space = strchr(tmpbuf, ' ')))
325                 *next_space = '\0';
326             mb_debug("multiboot loading module: %s\n", tmpbuf);
327             mb_mod_length = get_image_size(tmpbuf);
328             if (mb_mod_length < 0) {
329                 fprintf(stderr, "Failed to open file '%s'\n", tmpbuf);
330                 exit(1);
331             }
332 
333             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
334             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
335 
336             load_image(tmpbuf, (unsigned char *)mbs.mb_buf + offs);
337             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
338                        mbs.mb_buf_phys + offs + mb_mod_length, c);
339 
340             mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx"\n",
341                      (char *)mbs.mb_buf + offs,
342                      (char *)mbs.mb_buf + offs + mb_mod_length, c);
343             initrd_filename = next_initrd+1;
344         } while (not_last);
345     }
346 
347     /* Commandline support */
348     char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
349     snprintf(kcmdline, sizeof(kcmdline), "%s %s",
350              kernel_filename, kernel_cmdline);
351     stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
352 
353     stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));
354 
355     stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys + mbs.offset_mbinfo);
356     stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /* mods_count */
357 
358     /* the kernel is where we want it to be now */
359     stl_p(bootinfo + MBI_FLAGS, MULTIBOOT_FLAGS_MEMORY
360                                 | MULTIBOOT_FLAGS_BOOT_DEVICE
361                                 | MULTIBOOT_FLAGS_CMDLINE
362                                 | MULTIBOOT_FLAGS_MODULES
363                                 | MULTIBOOT_FLAGS_MMAP
364                                 | MULTIBOOT_FLAGS_BOOTLOADER);
365     stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the -boot switch? */
366     stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
367 
368     mb_debug("multiboot: mh_entry_addr = %#x\n", mh_entry_addr);
369     mb_debug("           mb_buf_phys   = "TARGET_FMT_plx"\n", mbs.mb_buf_phys);
370     mb_debug("           mod_start     = "TARGET_FMT_plx"\n", mbs.mb_buf_phys + mbs.offset_mods);
371     mb_debug("           mb_mods_count = %d\n", mbs.mb_mods_count);
372 
373     /* save bootinfo off the stack */
374     mb_bootinfo_data = g_memdup(bootinfo, sizeof(bootinfo));
375 
376     /* Pass variables to option rom */
377     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ENTRY, mh_entry_addr);
378     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_load_addr);
379     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, mbs.mb_buf_size);
380     fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA,
381                      mbs.mb_buf, mbs.mb_buf_size);
382 
383     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, ADDR_MBI);
384     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, sizeof(bootinfo));
385     fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, mb_bootinfo_data,
386                      sizeof(bootinfo));
387 
388     option_rom[nb_option_roms].name = "multiboot.bin";
389     option_rom[nb_option_roms].bootindex = 0;
390     nb_option_roms++;
391 
392     return 1; /* yes, we are multiboot */
393 }
394