xref: /openbmc/qemu/hw/i386/multiboot.c (revision 2822c1b6)
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/nvram/fw_cfg.h"
27 #include "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     MBI_BOOTLOADER  = 64,
58 
59     MBI_SIZE        = 88,
60 
61     /* Multiboot modules */
62     MB_MOD_START    = 0,
63     MB_MOD_END      = 4,
64     MB_MOD_CMDLINE  = 8,
65 
66     MB_MOD_SIZE     = 16,
67 
68     /* Region offsets */
69     ADDR_E820_MAP = MULTIBOOT_STRUCT_ADDR + 0,
70     ADDR_MBI      = ADDR_E820_MAP + 0x500,
71 
72     /* Multiboot flags */
73     MULTIBOOT_FLAGS_MEMORY      = 1 << 0,
74     MULTIBOOT_FLAGS_BOOT_DEVICE = 1 << 1,
75     MULTIBOOT_FLAGS_CMDLINE     = 1 << 2,
76     MULTIBOOT_FLAGS_MODULES     = 1 << 3,
77     MULTIBOOT_FLAGS_MMAP        = 1 << 6,
78     MULTIBOOT_FLAGS_BOOTLOADER  = 1 << 9,
79 };
80 
81 typedef struct {
82     /* buffer holding kernel, cmdlines and mb_infos */
83     void *mb_buf;
84     /* address in target */
85     hwaddr mb_buf_phys;
86     /* size of mb_buf in bytes */
87     unsigned mb_buf_size;
88     /* offset of mb-info's in bytes */
89     hwaddr offset_mbinfo;
90     /* offset in buffer for cmdlines in bytes */
91     hwaddr offset_cmdlines;
92     /* offset in buffer for bootloader name in bytes */
93     hwaddr offset_bootloader;
94     /* offset of modules in bytes */
95     hwaddr offset_mods;
96     /* available slots for mb modules infos */
97     int mb_mods_avail;
98     /* currently used slots of mb modules */
99     int mb_mods_count;
100 } MultibootState;
101 
102 const char *bootloader_name = "qemu";
103 
104 static uint32_t mb_add_cmdline(MultibootState *s, const char *cmdline)
105 {
106     hwaddr p = s->offset_cmdlines;
107     char *b = (char *)s->mb_buf + p;
108 
109     get_opt_value(b, strlen(cmdline) + 1, cmdline);
110     s->offset_cmdlines += strlen(b) + 1;
111     return s->mb_buf_phys + p;
112 }
113 
114 static uint32_t mb_add_bootloader(MultibootState *s, const char *bootloader)
115 {
116     hwaddr p = s->offset_bootloader;
117     char *b = (char *)s->mb_buf + p;
118 
119     memcpy(b, bootloader, strlen(bootloader) + 1);
120     s->offset_bootloader += strlen(b) + 1;
121     return s->mb_buf_phys + p;
122 }
123 
124 static void mb_add_mod(MultibootState *s,
125                        hwaddr start, hwaddr end,
126                        hwaddr cmdline_phys)
127 {
128     char *p;
129     assert(s->mb_mods_count < s->mb_mods_avail);
130 
131     p = (char *)s->mb_buf + s->offset_mbinfo + MB_MOD_SIZE * s->mb_mods_count;
132 
133     stl_p(p + MB_MOD_START,   start);
134     stl_p(p + MB_MOD_END,     end);
135     stl_p(p + MB_MOD_CMDLINE, cmdline_phys);
136 
137     mb_debug("mod%02d: "TARGET_FMT_plx" - "TARGET_FMT_plx"\n",
138              s->mb_mods_count, start, end);
139 
140     s->mb_mods_count++;
141 }
142 
143 int load_multiboot(FWCfgState *fw_cfg,
144                    FILE *f,
145                    const char *kernel_filename,
146                    const char *initrd_filename,
147                    const char *kernel_cmdline,
148                    int kernel_file_size,
149                    uint8_t *header)
150 {
151     int i, is_multiboot = 0;
152     uint32_t flags = 0;
153     uint32_t mh_entry_addr;
154     uint32_t mh_load_addr;
155     uint32_t mb_kernel_size;
156     MultibootState mbs;
157     uint8_t bootinfo[MBI_SIZE];
158     uint8_t *mb_bootinfo_data;
159     uint32_t cmdline_len;
160 
161     /* Ok, let's see if it is a multiboot image.
162        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
163     for (i = 0; i < (8192 - 48); i += 4) {
164         if (ldl_p(header+i) == 0x1BADB002) {
165             uint32_t checksum = ldl_p(header+i+8);
166             flags = ldl_p(header+i+4);
167             checksum += flags;
168             checksum += (uint32_t)0x1BADB002;
169             if (!checksum) {
170                 is_multiboot = 1;
171                 break;
172             }
173         }
174     }
175 
176     if (!is_multiboot)
177         return 0; /* no multiboot */
178 
179     mb_debug("qemu: I believe we found a multiboot image!\n");
180     memset(bootinfo, 0, sizeof(bootinfo));
181     memset(&mbs, 0, sizeof(mbs));
182 
183     if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
184         fprintf(stderr, "qemu: multiboot knows VBE. we don't.\n");
185     }
186     if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
187         uint64_t elf_entry;
188         uint64_t elf_low, elf_high;
189         int kernel_size;
190         fclose(f);
191 
192         if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
193             fprintf(stderr, "Cannot load x86-64 image, give a 32bit one.\n");
194             exit(1);
195         }
196 
197         kernel_size = load_elf(kernel_filename, NULL, NULL, &elf_entry,
198                                &elf_low, &elf_high, 0, ELF_MACHINE, 0);
199         if (kernel_size < 0) {
200             fprintf(stderr, "Error while loading elf kernel\n");
201             exit(1);
202         }
203         mh_load_addr = elf_low;
204         mb_kernel_size = elf_high - elf_low;
205         mh_entry_addr = elf_entry;
206 
207         mbs.mb_buf = g_malloc(mb_kernel_size);
208         if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
209             fprintf(stderr, "Error while fetching elf kernel from rom\n");
210             exit(1);
211         }
212 
213         mb_debug("qemu: loading multiboot-elf kernel (%#x bytes) with entry %#zx\n",
214                   mb_kernel_size, (size_t)mh_entry_addr);
215     } else {
216         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
217         uint32_t mh_header_addr = ldl_p(header+i+12);
218         uint32_t mh_load_end_addr = ldl_p(header+i+20);
219         uint32_t mh_bss_end_addr = ldl_p(header+i+24);
220         mh_load_addr = ldl_p(header+i+16);
221         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
222         uint32_t mb_load_size = 0;
223         mh_entry_addr = ldl_p(header+i+28);
224 
225         if (mh_load_end_addr) {
226             mb_kernel_size = mh_bss_end_addr - mh_load_addr;
227             mb_load_size = mh_load_end_addr - mh_load_addr;
228         } else {
229             mb_kernel_size = kernel_file_size - mb_kernel_text_offset;
230             mb_load_size = mb_kernel_size;
231         }
232 
233         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.
234         uint32_t mh_mode_type = ldl_p(header+i+32);
235         uint32_t mh_width = ldl_p(header+i+36);
236         uint32_t mh_height = ldl_p(header+i+40);
237         uint32_t mh_depth = ldl_p(header+i+44); */
238 
239         mb_debug("multiboot: mh_header_addr = %#x\n", mh_header_addr);
240         mb_debug("multiboot: mh_load_addr = %#x\n", mh_load_addr);
241         mb_debug("multiboot: mh_load_end_addr = %#x\n", mh_load_end_addr);
242         mb_debug("multiboot: mh_bss_end_addr = %#x\n", mh_bss_end_addr);
243         mb_debug("qemu: loading multiboot kernel (%#x bytes) at %#x\n",
244                  mb_load_size, mh_load_addr);
245 
246         mbs.mb_buf = g_malloc(mb_kernel_size);
247         fseek(f, mb_kernel_text_offset, SEEK_SET);
248         if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
249             fprintf(stderr, "fread() failed\n");
250             exit(1);
251         }
252         memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
253         fclose(f);
254     }
255 
256     mbs.mb_buf_phys = mh_load_addr;
257 
258     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
259     mbs.offset_mbinfo = mbs.mb_buf_size;
260 
261     /* Calculate space for cmdlines, bootloader name, and mb_mods */
262     cmdline_len = strlen(kernel_filename) + 1;
263     cmdline_len += strlen(kernel_cmdline) + 1;
264     if (initrd_filename) {
265         const char *r = initrd_filename;
266         cmdline_len += strlen(r) + 1;
267         mbs.mb_mods_avail = 1;
268         while (*(r = get_opt_value(NULL, 0, r))) {
269            mbs.mb_mods_avail++;
270            r++;
271         }
272     }
273 
274     mbs.mb_buf_size += cmdline_len;
275     mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
276     mbs.mb_buf_size += strlen(bootloader_name) + 1;
277 
278     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
279 
280     /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
281     mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
282     mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
283     mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
284 
285     if (initrd_filename) {
286         char *next_initrd, not_last;
287 
288         mbs.offset_mods = mbs.mb_buf_size;
289 
290         do {
291             char *next_space;
292             int mb_mod_length;
293             uint32_t offs = mbs.mb_buf_size;
294 
295             next_initrd = (char *)get_opt_value(NULL, 0, initrd_filename);
296             not_last = *next_initrd;
297             *next_initrd = '\0';
298             /* if a space comes after the module filename, treat everything
299                after that as parameters */
300             hwaddr c = mb_add_cmdline(&mbs, initrd_filename);
301             if ((next_space = strchr(initrd_filename, ' ')))
302                 *next_space = '\0';
303             mb_debug("multiboot loading module: %s\n", initrd_filename);
304             mb_mod_length = get_image_size(initrd_filename);
305             if (mb_mod_length < 0) {
306                 fprintf(stderr, "Failed to open file '%s'\n", initrd_filename);
307                 exit(1);
308             }
309 
310             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
311             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
312 
313             load_image(initrd_filename, (unsigned char *)mbs.mb_buf + offs);
314             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
315                        mbs.mb_buf_phys + offs + mb_mod_length, c);
316 
317             mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx"\n",
318                      (char *)mbs.mb_buf + offs,
319                      (char *)mbs.mb_buf + offs + mb_mod_length, c);
320             initrd_filename = next_initrd+1;
321         } while (not_last);
322     }
323 
324     /* Commandline support */
325     char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
326     snprintf(kcmdline, sizeof(kcmdline), "%s %s",
327              kernel_filename, kernel_cmdline);
328     stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
329 
330     stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));
331 
332     stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys + mbs.offset_mbinfo);
333     stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /* mods_count */
334 
335     /* the kernel is where we want it to be now */
336     stl_p(bootinfo + MBI_FLAGS, MULTIBOOT_FLAGS_MEMORY
337                                 | MULTIBOOT_FLAGS_BOOT_DEVICE
338                                 | MULTIBOOT_FLAGS_CMDLINE
339                                 | MULTIBOOT_FLAGS_MODULES
340                                 | MULTIBOOT_FLAGS_MMAP
341                                 | MULTIBOOT_FLAGS_BOOTLOADER);
342     stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the -boot switch? */
343     stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
344 
345     mb_debug("multiboot: mh_entry_addr = %#x\n", mh_entry_addr);
346     mb_debug("           mb_buf_phys   = "TARGET_FMT_plx"\n", mbs.mb_buf_phys);
347     mb_debug("           mod_start     = "TARGET_FMT_plx"\n", mbs.mb_buf_phys + mbs.offset_mods);
348     mb_debug("           mb_mods_count = %d\n", mbs.mb_mods_count);
349 
350     /* save bootinfo off the stack */
351     mb_bootinfo_data = g_malloc(sizeof(bootinfo));
352     memcpy(mb_bootinfo_data, bootinfo, sizeof(bootinfo));
353 
354     /* Pass variables to option rom */
355     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ENTRY, mh_entry_addr);
356     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_load_addr);
357     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, mbs.mb_buf_size);
358     fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA,
359                      mbs.mb_buf, mbs.mb_buf_size);
360 
361     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, ADDR_MBI);
362     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, sizeof(bootinfo));
363     fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, mb_bootinfo_data,
364                      sizeof(bootinfo));
365 
366     option_rom[nb_option_roms].name = "multiboot.bin";
367     option_rom[nb_option_roms].bootindex = 0;
368     nb_option_roms++;
369 
370     return 1; /* yes, we are multiboot */
371 }
372