xref: /openbmc/qemu/hw/i386/multiboot.c (revision dfa9c2a0f4d0a0c8b2c1449ecdbb1297427e1560)
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 
160     /* Ok, let's see if it is a multiboot image.
161        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
162     for (i = 0; i < (8192 - 48); i += 4) {
163         if (ldl_p(header+i) == 0x1BADB002) {
164             uint32_t checksum = ldl_p(header+i+8);
165             flags = ldl_p(header+i+4);
166             checksum += flags;
167             checksum += (uint32_t)0x1BADB002;
168             if (!checksum) {
169                 is_multiboot = 1;
170                 break;
171             }
172         }
173     }
174 
175     if (!is_multiboot)
176         return 0; /* no multiboot */
177 
178     mb_debug("qemu: I believe we found a multiboot image!\n");
179     memset(bootinfo, 0, sizeof(bootinfo));
180     memset(&mbs, 0, sizeof(mbs));
181 
182     if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
183         fprintf(stderr, "qemu: multiboot knows VBE. we don't.\n");
184     }
185     if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
186         uint64_t elf_entry;
187         uint64_t elf_low, elf_high;
188         int kernel_size;
189         fclose(f);
190 
191         if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
192             fprintf(stderr, "Cannot load x86-64 image, give a 32bit one.\n");
193             exit(1);
194         }
195 
196         kernel_size = load_elf(kernel_filename, NULL, NULL, &elf_entry,
197                                &elf_low, &elf_high, 0, ELF_MACHINE, 0);
198         if (kernel_size < 0) {
199             fprintf(stderr, "Error while loading elf kernel\n");
200             exit(1);
201         }
202         mh_load_addr = elf_low;
203         mb_kernel_size = elf_high - elf_low;
204         mh_entry_addr = elf_entry;
205 
206         mbs.mb_buf = g_malloc(mb_kernel_size);
207         if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
208             fprintf(stderr, "Error while fetching elf kernel from rom\n");
209             exit(1);
210         }
211 
212         mb_debug("qemu: loading multiboot-elf kernel (%#x bytes) with entry %#zx\n",
213                   mb_kernel_size, (size_t)mh_entry_addr);
214     } else {
215         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
216         uint32_t mh_header_addr = ldl_p(header+i+12);
217         uint32_t mh_load_end_addr = ldl_p(header+i+20);
218         uint32_t mh_bss_end_addr = ldl_p(header+i+24);
219         mh_load_addr = ldl_p(header+i+16);
220         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
221         uint32_t mb_load_size = 0;
222         mh_entry_addr = ldl_p(header+i+28);
223 
224         if (mh_load_end_addr) {
225             mb_kernel_size = mh_bss_end_addr - mh_load_addr;
226             mb_load_size = mh_load_end_addr - mh_load_addr;
227         } else {
228             mb_kernel_size = kernel_file_size - mb_kernel_text_offset;
229             mb_load_size = mb_kernel_size;
230         }
231 
232         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.
233         uint32_t mh_mode_type = ldl_p(header+i+32);
234         uint32_t mh_width = ldl_p(header+i+36);
235         uint32_t mh_height = ldl_p(header+i+40);
236         uint32_t mh_depth = ldl_p(header+i+44); */
237 
238         mb_debug("multiboot: mh_header_addr = %#x\n", mh_header_addr);
239         mb_debug("multiboot: mh_load_addr = %#x\n", mh_load_addr);
240         mb_debug("multiboot: mh_load_end_addr = %#x\n", mh_load_end_addr);
241         mb_debug("multiboot: mh_bss_end_addr = %#x\n", mh_bss_end_addr);
242         mb_debug("qemu: loading multiboot kernel (%#x bytes) at %#x\n",
243                  mb_load_size, mh_load_addr);
244 
245         mbs.mb_buf = g_malloc(mb_kernel_size);
246         fseek(f, mb_kernel_text_offset, SEEK_SET);
247         if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
248             fprintf(stderr, "fread() failed\n");
249             exit(1);
250         }
251         memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
252         fclose(f);
253     }
254 
255     mbs.mb_buf_phys = mh_load_addr;
256 
257     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
258     mbs.offset_mbinfo = mbs.mb_buf_size;
259 
260     /* Calculate space for cmdlines, bootloader name, and mb_mods */
261     mbs.mb_buf_size += strlen(kernel_filename) + 1;
262     mbs.mb_buf_size += strlen(kernel_cmdline) + 1;
263     mbs.mb_buf_size += strlen(bootloader_name) + 1;
264     if (initrd_filename) {
265         const char *r = initrd_filename;
266         mbs.mb_buf_size += 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         mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
273     }
274 
275     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
276 
277     /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
278     mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
279     mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
280     mbs.offset_bootloader = mbs.offset_cmdlines + strlen(kernel_filename) + 1
281                             + strlen(kernel_cmdline) + 1;
282 
283     if (initrd_filename) {
284         char *next_initrd, not_last;
285 
286         mbs.offset_mods = mbs.mb_buf_size;
287 
288         do {
289             char *next_space;
290             int mb_mod_length;
291             uint32_t offs = mbs.mb_buf_size;
292 
293             next_initrd = (char *)get_opt_value(NULL, 0, initrd_filename);
294             not_last = *next_initrd;
295             *next_initrd = '\0';
296             /* if a space comes after the module filename, treat everything
297                after that as parameters */
298             hwaddr c = mb_add_cmdline(&mbs, initrd_filename);
299             if ((next_space = strchr(initrd_filename, ' ')))
300                 *next_space = '\0';
301             mb_debug("multiboot loading module: %s\n", initrd_filename);
302             mb_mod_length = get_image_size(initrd_filename);
303             if (mb_mod_length < 0) {
304                 fprintf(stderr, "Failed to open file '%s'\n", initrd_filename);
305                 exit(1);
306             }
307 
308             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
309             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
310 
311             load_image(initrd_filename, (unsigned char *)mbs.mb_buf + offs);
312             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
313                        mbs.mb_buf_phys + offs + mb_mod_length, c);
314 
315             mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx"\n",
316                      (char *)mbs.mb_buf + offs,
317                      (char *)mbs.mb_buf + offs + mb_mod_length, c);
318             initrd_filename = next_initrd+1;
319         } while (not_last);
320     }
321 
322     /* Commandline support */
323     char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
324     snprintf(kcmdline, sizeof(kcmdline), "%s %s",
325              kernel_filename, kernel_cmdline);
326     stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
327 
328     stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));
329 
330     stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys + mbs.offset_mbinfo);
331     stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /* mods_count */
332 
333     /* the kernel is where we want it to be now */
334     stl_p(bootinfo + MBI_FLAGS, MULTIBOOT_FLAGS_MEMORY
335                                 | MULTIBOOT_FLAGS_BOOT_DEVICE
336                                 | MULTIBOOT_FLAGS_CMDLINE
337                                 | MULTIBOOT_FLAGS_MODULES
338                                 | MULTIBOOT_FLAGS_MMAP
339                                 | MULTIBOOT_FLAGS_BOOTLOADER);
340     stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the -boot switch? */
341     stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
342 
343     mb_debug("multiboot: mh_entry_addr = %#x\n", mh_entry_addr);
344     mb_debug("           mb_buf_phys   = "TARGET_FMT_plx"\n", mbs.mb_buf_phys);
345     mb_debug("           mod_start     = "TARGET_FMT_plx"\n", mbs.mb_buf_phys + mbs.offset_mods);
346     mb_debug("           mb_mods_count = %d\n", mbs.mb_mods_count);
347 
348     /* save bootinfo off the stack */
349     mb_bootinfo_data = g_malloc(sizeof(bootinfo));
350     memcpy(mb_bootinfo_data, bootinfo, sizeof(bootinfo));
351 
352     /* Pass variables to option rom */
353     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ENTRY, mh_entry_addr);
354     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_load_addr);
355     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, mbs.mb_buf_size);
356     fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA,
357                      mbs.mb_buf, mbs.mb_buf_size);
358 
359     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, ADDR_MBI);
360     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, sizeof(bootinfo));
361     fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, mb_bootinfo_data,
362                      sizeof(bootinfo));
363 
364     option_rom[nb_option_roms].name = "multiboot.bin";
365     option_rom[nb_option_roms].bootindex = 0;
366     nb_option_roms++;
367 
368     return 1; /* yes, we are multiboot */
369 }
370