xref: /openbmc/qemu/hw/i386/multiboot.c (revision c71c3e99)
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 "hw/hw.h"
26 #include "hw/fw_cfg.h"
27 #include "hw/multiboot.h"
28 #include "hw/loader.h"
29 #include "elf.h"
30 #include "sysemu/sysemu.h"
31 
32 /* Show multiboot debug output */
33 //#define DEBUG_MULTIBOOT
34 
35 #ifdef DEBUG_MULTIBOOT
36 #define mb_debug(a...) fprintf(stderr, ## a)
37 #else
38 #define mb_debug(a...)
39 #endif
40 
41 #define MULTIBOOT_STRUCT_ADDR 0x9000
42 
43 #if MULTIBOOT_STRUCT_ADDR > 0xf0000
44 #error multiboot struct needs to fit in 16 bit real mode
45 #endif
46 
47 enum {
48     /* Multiboot info */
49     MBI_FLAGS       = 0,
50     MBI_MEM_LOWER   = 4,
51     MBI_MEM_UPPER   = 8,
52     MBI_BOOT_DEVICE = 12,
53     MBI_CMDLINE     = 16,
54     MBI_MODS_COUNT  = 20,
55     MBI_MODS_ADDR   = 24,
56     MBI_MMAP_ADDR   = 48,
57 
58     MBI_SIZE        = 88,
59 
60     /* Multiboot modules */
61     MB_MOD_START    = 0,
62     MB_MOD_END      = 4,
63     MB_MOD_CMDLINE  = 8,
64 
65     MB_MOD_SIZE     = 16,
66 
67     /* Region offsets */
68     ADDR_E820_MAP = MULTIBOOT_STRUCT_ADDR + 0,
69     ADDR_MBI      = ADDR_E820_MAP + 0x500,
70 
71     /* Multiboot flags */
72     MULTIBOOT_FLAGS_MEMORY      = 1 << 0,
73     MULTIBOOT_FLAGS_BOOT_DEVICE = 1 << 1,
74     MULTIBOOT_FLAGS_CMDLINE     = 1 << 2,
75     MULTIBOOT_FLAGS_MODULES     = 1 << 3,
76     MULTIBOOT_FLAGS_MMAP        = 1 << 6,
77 };
78 
79 typedef struct {
80     /* buffer holding kernel, cmdlines and mb_infos */
81     void *mb_buf;
82     /* address in target */
83     hwaddr mb_buf_phys;
84     /* size of mb_buf in bytes */
85     unsigned mb_buf_size;
86     /* offset of mb-info's in bytes */
87     hwaddr offset_mbinfo;
88     /* offset in buffer for cmdlines in bytes */
89     hwaddr offset_cmdlines;
90     /* offset of modules in bytes */
91     hwaddr offset_mods;
92     /* available slots for mb modules infos */
93     int mb_mods_avail;
94     /* currently used slots of mb modules */
95     int mb_mods_count;
96 } MultibootState;
97 
98 static uint32_t mb_add_cmdline(MultibootState *s, const char *cmdline)
99 {
100     hwaddr p = s->offset_cmdlines;
101     char *b = (char *)s->mb_buf + p;
102 
103     get_opt_value(b, strlen(cmdline) + 1, cmdline);
104     s->offset_cmdlines += strlen(b) + 1;
105     return s->mb_buf_phys + p;
106 }
107 
108 static void mb_add_mod(MultibootState *s,
109                        hwaddr start, hwaddr end,
110                        hwaddr cmdline_phys)
111 {
112     char *p;
113     assert(s->mb_mods_count < s->mb_mods_avail);
114 
115     p = (char *)s->mb_buf + s->offset_mbinfo + MB_MOD_SIZE * s->mb_mods_count;
116 
117     stl_p(p + MB_MOD_START,   start);
118     stl_p(p + MB_MOD_END,     end);
119     stl_p(p + MB_MOD_CMDLINE, cmdline_phys);
120 
121     mb_debug("mod%02d: "TARGET_FMT_plx" - "TARGET_FMT_plx"\n",
122              s->mb_mods_count, start, end);
123 
124     s->mb_mods_count++;
125 }
126 
127 int load_multiboot(void *fw_cfg,
128                    FILE *f,
129                    const char *kernel_filename,
130                    const char *initrd_filename,
131                    const char *kernel_cmdline,
132                    int kernel_file_size,
133                    uint8_t *header)
134 {
135     int i, is_multiboot = 0;
136     uint32_t flags = 0;
137     uint32_t mh_entry_addr;
138     uint32_t mh_load_addr;
139     uint32_t mb_kernel_size;
140     MultibootState mbs;
141     uint8_t bootinfo[MBI_SIZE];
142     uint8_t *mb_bootinfo_data;
143 
144     /* Ok, let's see if it is a multiboot image.
145        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
146     for (i = 0; i < (8192 - 48); i += 4) {
147         if (ldl_p(header+i) == 0x1BADB002) {
148             uint32_t checksum = ldl_p(header+i+8);
149             flags = ldl_p(header+i+4);
150             checksum += flags;
151             checksum += (uint32_t)0x1BADB002;
152             if (!checksum) {
153                 is_multiboot = 1;
154                 break;
155             }
156         }
157     }
158 
159     if (!is_multiboot)
160         return 0; /* no multiboot */
161 
162     mb_debug("qemu: I believe we found a multiboot image!\n");
163     memset(bootinfo, 0, sizeof(bootinfo));
164     memset(&mbs, 0, sizeof(mbs));
165 
166     if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
167         fprintf(stderr, "qemu: multiboot knows VBE. we don't.\n");
168     }
169     if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
170         uint64_t elf_entry;
171         uint64_t elf_low, elf_high;
172         int kernel_size;
173         fclose(f);
174 
175         if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
176             fprintf(stderr, "Cannot load x86-64 image, give a 32bit one.\n");
177             exit(1);
178         }
179 
180         kernel_size = load_elf(kernel_filename, NULL, NULL, &elf_entry,
181                                &elf_low, &elf_high, 0, ELF_MACHINE, 0);
182         if (kernel_size < 0) {
183             fprintf(stderr, "Error while loading elf kernel\n");
184             exit(1);
185         }
186         mh_load_addr = elf_low;
187         mb_kernel_size = elf_high - elf_low;
188         mh_entry_addr = elf_entry;
189 
190         mbs.mb_buf = g_malloc(mb_kernel_size);
191         if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
192             fprintf(stderr, "Error while fetching elf kernel from rom\n");
193             exit(1);
194         }
195 
196         mb_debug("qemu: loading multiboot-elf kernel (%#x bytes) with entry %#zx\n",
197                   mb_kernel_size, (size_t)mh_entry_addr);
198     } else {
199         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
200         uint32_t mh_header_addr = ldl_p(header+i+12);
201         uint32_t mh_load_end_addr = ldl_p(header+i+20);
202         uint32_t mh_bss_end_addr = ldl_p(header+i+24);
203         mh_load_addr = ldl_p(header+i+16);
204         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
205         uint32_t mb_load_size = 0;
206         mh_entry_addr = ldl_p(header+i+28);
207 
208         if (mh_load_end_addr) {
209             mb_kernel_size = mh_bss_end_addr - mh_load_addr;
210             mb_load_size = mh_load_end_addr - mh_load_addr;
211         } else {
212             mb_kernel_size = kernel_file_size - mb_kernel_text_offset;
213             mb_load_size = mb_kernel_size;
214         }
215 
216         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.
217         uint32_t mh_mode_type = ldl_p(header+i+32);
218         uint32_t mh_width = ldl_p(header+i+36);
219         uint32_t mh_height = ldl_p(header+i+40);
220         uint32_t mh_depth = ldl_p(header+i+44); */
221 
222         mb_debug("multiboot: mh_header_addr = %#x\n", mh_header_addr);
223         mb_debug("multiboot: mh_load_addr = %#x\n", mh_load_addr);
224         mb_debug("multiboot: mh_load_end_addr = %#x\n", mh_load_end_addr);
225         mb_debug("multiboot: mh_bss_end_addr = %#x\n", mh_bss_end_addr);
226         mb_debug("qemu: loading multiboot kernel (%#x bytes) at %#x\n",
227                  mb_load_size, mh_load_addr);
228 
229         mbs.mb_buf = g_malloc(mb_kernel_size);
230         fseek(f, mb_kernel_text_offset, SEEK_SET);
231         if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
232             fprintf(stderr, "fread() failed\n");
233             exit(1);
234         }
235         memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
236         fclose(f);
237     }
238 
239     mbs.mb_buf_phys = mh_load_addr;
240 
241     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
242     mbs.offset_mbinfo = mbs.mb_buf_size;
243 
244     /* Calculate space for cmdlines and mb_mods */
245     mbs.mb_buf_size += strlen(kernel_filename) + 1;
246     mbs.mb_buf_size += strlen(kernel_cmdline) + 1;
247     if (initrd_filename) {
248         const char *r = initrd_filename;
249         mbs.mb_buf_size += strlen(r) + 1;
250         mbs.mb_mods_avail = 1;
251         while (*(r = get_opt_value(NULL, 0, r))) {
252            mbs.mb_mods_avail++;
253            r++;
254         }
255         mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
256     }
257 
258     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
259 
260     /* enlarge mb_buf to hold cmdlines and mb-info structs */
261     mbs.mb_buf          = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
262     mbs.offset_cmdlines = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
263 
264     if (initrd_filename) {
265         char *next_initrd, not_last;
266 
267         mbs.offset_mods = mbs.mb_buf_size;
268 
269         do {
270             char *next_space;
271             int mb_mod_length;
272             uint32_t offs = mbs.mb_buf_size;
273 
274             next_initrd = (char *)get_opt_value(NULL, 0, initrd_filename);
275             not_last = *next_initrd;
276             *next_initrd = '\0';
277             /* if a space comes after the module filename, treat everything
278                after that as parameters */
279             hwaddr c = mb_add_cmdline(&mbs, initrd_filename);
280             if ((next_space = strchr(initrd_filename, ' ')))
281                 *next_space = '\0';
282             mb_debug("multiboot loading module: %s\n", initrd_filename);
283             mb_mod_length = get_image_size(initrd_filename);
284             if (mb_mod_length < 0) {
285                 fprintf(stderr, "Failed to open file '%s'\n", initrd_filename);
286                 exit(1);
287             }
288 
289             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
290             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
291 
292             load_image(initrd_filename, (unsigned char *)mbs.mb_buf + offs);
293             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
294                        mbs.mb_buf_phys + offs + mb_mod_length, c);
295 
296             mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx"\n",
297                      (char *)mbs.mb_buf + offs,
298                      (char *)mbs.mb_buf + offs + mb_mod_length, c);
299             initrd_filename = next_initrd+1;
300         } while (not_last);
301     }
302 
303     /* Commandline support */
304     char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
305     snprintf(kcmdline, sizeof(kcmdline), "%s %s",
306              kernel_filename, kernel_cmdline);
307     stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
308 
309     stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys + mbs.offset_mbinfo);
310     stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /* mods_count */
311 
312     /* the kernel is where we want it to be now */
313     stl_p(bootinfo + MBI_FLAGS, MULTIBOOT_FLAGS_MEMORY
314                                 | MULTIBOOT_FLAGS_BOOT_DEVICE
315                                 | MULTIBOOT_FLAGS_CMDLINE
316                                 | MULTIBOOT_FLAGS_MODULES
317                                 | MULTIBOOT_FLAGS_MMAP);
318     stl_p(bootinfo + MBI_MEM_LOWER,   640);
319     stl_p(bootinfo + MBI_MEM_UPPER,   (ram_size / 1024) - 1024);
320     stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the -boot switch? */
321     stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
322 
323     mb_debug("multiboot: mh_entry_addr = %#x\n", mh_entry_addr);
324     mb_debug("           mb_buf_phys   = "TARGET_FMT_plx"\n", mbs.mb_buf_phys);
325     mb_debug("           mod_start     = "TARGET_FMT_plx"\n", mbs.mb_buf_phys + mbs.offset_mods);
326     mb_debug("           mb_mods_count = %d\n", mbs.mb_mods_count);
327 
328     /* save bootinfo off the stack */
329     mb_bootinfo_data = g_malloc(sizeof(bootinfo));
330     memcpy(mb_bootinfo_data, bootinfo, sizeof(bootinfo));
331 
332     /* Pass variables to option rom */
333     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ENTRY, mh_entry_addr);
334     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_load_addr);
335     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, mbs.mb_buf_size);
336     fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA,
337                      mbs.mb_buf, mbs.mb_buf_size);
338 
339     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, ADDR_MBI);
340     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, sizeof(bootinfo));
341     fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, mb_bootinfo_data,
342                      sizeof(bootinfo));
343 
344     option_rom[nb_option_roms].name = "multiboot.bin";
345     option_rom[nb_option_roms].bootindex = 0;
346     nb_option_roms++;
347 
348     return 1; /* yes, we are multiboot */
349 }
350