xref: /openbmc/qemu/hw/i386/multiboot.c (revision da054c64)
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 #include "qemu/error-report.h"
35 
36 /* Show multiboot debug output */
37 //#define DEBUG_MULTIBOOT
38 
39 #ifdef DEBUG_MULTIBOOT
40 #define mb_debug(a...) error_report(a)
41 #else
42 #define mb_debug(a...)
43 #endif
44 
45 #define MULTIBOOT_STRUCT_ADDR 0x9000
46 
47 #if MULTIBOOT_STRUCT_ADDR > 0xf0000
48 #error multiboot struct needs to fit in 16 bit real mode
49 #endif
50 
51 enum {
52     /* Multiboot info */
53     MBI_FLAGS       = 0,
54     MBI_MEM_LOWER   = 4,
55     MBI_MEM_UPPER   = 8,
56     MBI_BOOT_DEVICE = 12,
57     MBI_CMDLINE     = 16,
58     MBI_MODS_COUNT  = 20,
59     MBI_MODS_ADDR   = 24,
60     MBI_MMAP_ADDR   = 48,
61     MBI_BOOTLOADER  = 64,
62 
63     MBI_SIZE        = 88,
64 
65     /* Multiboot modules */
66     MB_MOD_START    = 0,
67     MB_MOD_END      = 4,
68     MB_MOD_CMDLINE  = 8,
69 
70     MB_MOD_SIZE     = 16,
71 
72     /* Region offsets */
73     ADDR_E820_MAP = MULTIBOOT_STRUCT_ADDR + 0,
74     ADDR_MBI      = ADDR_E820_MAP + 0x500,
75 
76     /* Multiboot flags */
77     MULTIBOOT_FLAGS_MEMORY      = 1 << 0,
78     MULTIBOOT_FLAGS_BOOT_DEVICE = 1 << 1,
79     MULTIBOOT_FLAGS_CMDLINE     = 1 << 2,
80     MULTIBOOT_FLAGS_MODULES     = 1 << 3,
81     MULTIBOOT_FLAGS_MMAP        = 1 << 6,
82     MULTIBOOT_FLAGS_BOOTLOADER  = 1 << 9,
83 };
84 
85 typedef struct {
86     /* buffer holding kernel, cmdlines and mb_infos */
87     void *mb_buf;
88     /* address in target */
89     hwaddr mb_buf_phys;
90     /* size of mb_buf in bytes */
91     unsigned mb_buf_size;
92     /* offset of mb-info's in bytes */
93     hwaddr offset_mbinfo;
94     /* offset in buffer for cmdlines in bytes */
95     hwaddr offset_cmdlines;
96     /* offset in buffer for bootloader name in bytes */
97     hwaddr offset_bootloader;
98     /* offset of modules in bytes */
99     hwaddr offset_mods;
100     /* available slots for mb modules infos */
101     int mb_mods_avail;
102     /* currently used slots of mb modules */
103     int mb_mods_count;
104 } MultibootState;
105 
106 const char *bootloader_name = "qemu";
107 
108 static uint32_t mb_add_cmdline(MultibootState *s, const char *cmdline)
109 {
110     hwaddr p = s->offset_cmdlines;
111     char *b = (char *)s->mb_buf + p;
112 
113     memcpy(b, cmdline, strlen(cmdline) + 1);
114     s->offset_cmdlines += strlen(b) + 1;
115     return s->mb_buf_phys + p;
116 }
117 
118 static uint32_t mb_add_bootloader(MultibootState *s, const char *bootloader)
119 {
120     hwaddr p = s->offset_bootloader;
121     char *b = (char *)s->mb_buf + p;
122 
123     memcpy(b, bootloader, strlen(bootloader) + 1);
124     s->offset_bootloader += strlen(b) + 1;
125     return s->mb_buf_phys + p;
126 }
127 
128 static void mb_add_mod(MultibootState *s,
129                        hwaddr start, hwaddr end,
130                        hwaddr cmdline_phys)
131 {
132     char *p;
133     assert(s->mb_mods_count < s->mb_mods_avail);
134 
135     p = (char *)s->mb_buf + s->offset_mbinfo + MB_MOD_SIZE * s->mb_mods_count;
136 
137     stl_p(p + MB_MOD_START,   start);
138     stl_p(p + MB_MOD_END,     end);
139     stl_p(p + MB_MOD_CMDLINE, cmdline_phys);
140 
141     mb_debug("mod%02d: "TARGET_FMT_plx" - "TARGET_FMT_plx,
142              s->mb_mods_count, start, end);
143 
144     s->mb_mods_count++;
145 }
146 
147 int load_multiboot(FWCfgState *fw_cfg,
148                    FILE *f,
149                    const char *kernel_filename,
150                    const char *initrd_filename,
151                    const char *kernel_cmdline,
152                    int kernel_file_size,
153                    uint8_t *header)
154 {
155     int i, is_multiboot = 0;
156     uint32_t flags = 0;
157     uint32_t mh_entry_addr;
158     uint32_t mh_load_addr;
159     uint32_t mb_kernel_size;
160     MultibootState mbs;
161     uint8_t bootinfo[MBI_SIZE];
162     uint8_t *mb_bootinfo_data;
163     uint32_t cmdline_len;
164     GList *mods = NULL;
165 
166     /* Ok, let's see if it is a multiboot image.
167        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
168     for (i = 0; i < (8192 - 48); i += 4) {
169         if (ldl_p(header+i) == 0x1BADB002) {
170             uint32_t checksum = ldl_p(header+i+8);
171             flags = ldl_p(header+i+4);
172             checksum += flags;
173             checksum += (uint32_t)0x1BADB002;
174             if (!checksum) {
175                 is_multiboot = 1;
176                 break;
177             }
178         }
179     }
180 
181     if (!is_multiboot)
182         return 0; /* no multiboot */
183 
184     mb_debug("I believe we found a multiboot image!");
185     memset(bootinfo, 0, sizeof(bootinfo));
186     memset(&mbs, 0, sizeof(mbs));
187 
188     if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
189         error_report("multiboot knows VBE. we don't");
190     }
191     if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
192         uint64_t elf_entry;
193         uint64_t elf_low, elf_high;
194         int kernel_size;
195         fclose(f);
196 
197         if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
198             error_report("Cannot load x86-64 image, give a 32bit one.");
199             exit(1);
200         }
201 
202         kernel_size = load_elf(kernel_filename, NULL, NULL, &elf_entry,
203                                &elf_low, &elf_high, 0, I386_ELF_MACHINE,
204                                0, 0);
205         if (kernel_size < 0) {
206             error_report("Error while loading elf kernel");
207             exit(1);
208         }
209         mh_load_addr = elf_low;
210         mb_kernel_size = elf_high - elf_low;
211         mh_entry_addr = elf_entry;
212 
213         mbs.mb_buf = g_malloc(mb_kernel_size);
214         if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
215             error_report("Error while fetching elf kernel from rom");
216             exit(1);
217         }
218 
219         mb_debug("loading multiboot-elf kernel "
220                  "(%#x bytes) with entry %#zx",
221                  mb_kernel_size, (size_t)mh_entry_addr);
222     } else {
223         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
224         uint32_t mh_header_addr = ldl_p(header+i+12);
225         uint32_t mh_load_end_addr = ldl_p(header+i+20);
226         uint32_t mh_bss_end_addr = ldl_p(header+i+24);
227 
228         mh_load_addr = ldl_p(header+i+16);
229         if (mh_header_addr < mh_load_addr) {
230             error_report("invalid load_addr address");
231             exit(1);
232         }
233         if (mh_header_addr - mh_load_addr > i) {
234             error_report("invalid header_addr address");
235             exit(1);
236         }
237 
238         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
239         uint32_t mb_load_size = 0;
240         mh_entry_addr = ldl_p(header+i+28);
241 
242         if (mh_load_end_addr) {
243             if (mh_load_end_addr < mh_load_addr) {
244                 error_report("invalid load_end_addr address");
245                 exit(1);
246             }
247             mb_load_size = mh_load_end_addr - mh_load_addr;
248         } else {
249             if (kernel_file_size < mb_kernel_text_offset) {
250                 error_report("invalid kernel_file_size");
251                 exit(1);
252             }
253             mb_load_size = kernel_file_size - mb_kernel_text_offset;
254         }
255         if (mb_load_size > UINT32_MAX - mh_load_addr) {
256             error_report("kernel does not fit in address space");
257             exit(1);
258         }
259         if (mh_bss_end_addr) {
260             if (mh_bss_end_addr < (mh_load_addr + mb_load_size)) {
261                 error_report("invalid bss_end_addr address");
262                 exit(1);
263             }
264             mb_kernel_size = mh_bss_end_addr - mh_load_addr;
265         } else {
266             mb_kernel_size = mb_load_size;
267         }
268 
269         mb_debug("multiboot: header_addr = %#x", mh_header_addr);
270         mb_debug("multiboot: load_addr = %#x", mh_load_addr);
271         mb_debug("multiboot: load_end_addr = %#x", mh_load_end_addr);
272         mb_debug("multiboot: bss_end_addr = %#x", mh_bss_end_addr);
273         mb_debug("loading multiboot kernel (%#x bytes) at %#x",
274                  mb_load_size, mh_load_addr);
275 
276         mbs.mb_buf = g_malloc(mb_kernel_size);
277         fseek(f, mb_kernel_text_offset, SEEK_SET);
278         if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
279             error_report("fread() failed");
280             exit(1);
281         }
282         memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
283         fclose(f);
284     }
285 
286     mbs.mb_buf_phys = mh_load_addr;
287 
288     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
289     mbs.offset_mbinfo = mbs.mb_buf_size;
290 
291     /* Calculate space for cmdlines, bootloader name, and mb_mods */
292     cmdline_len = strlen(kernel_filename) + 1;
293     cmdline_len += strlen(kernel_cmdline) + 1;
294     if (initrd_filename) {
295         const char *r = initrd_filename;
296         cmdline_len += strlen(initrd_filename) + 1;
297         while (*r) {
298             char *value;
299             r = get_opt_value(r, &value);
300             mbs.mb_mods_avail++;
301             mods = g_list_append(mods, value);
302             if (*r) {
303                 r++;
304             }
305         }
306     }
307 
308     mbs.mb_buf_size += cmdline_len;
309     mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
310     mbs.mb_buf_size += strlen(bootloader_name) + 1;
311 
312     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
313 
314     /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
315     mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
316     mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
317     mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
318 
319     if (mods) {
320         GList *tmpl = mods;
321         mbs.offset_mods = mbs.mb_buf_size;
322 
323         while (tmpl) {
324             char *next_space;
325             int mb_mod_length;
326             uint32_t offs = mbs.mb_buf_size;
327             char *one_file = tmpl->data;
328 
329             /* if a space comes after the module filename, treat everything
330                after that as parameters */
331             hwaddr c = mb_add_cmdline(&mbs, one_file);
332             next_space = strchr(one_file, ' ');
333             if (next_space) {
334                 *next_space = '\0';
335             }
336             mb_debug("multiboot loading module: %s", one_file);
337             mb_mod_length = get_image_size(one_file);
338             if (mb_mod_length < 0) {
339                 error_report("Failed to open file '%s'", one_file);
340                 exit(1);
341             }
342 
343             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
344             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
345 
346             if (load_image_size(one_file, (unsigned char *)mbs.mb_buf + offs,
347                                 mbs.mb_buf_size - offs) < 0) {
348                 error_report("Error loading file '%s'", one_file);
349                 exit(1);
350             }
351             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
352                        mbs.mb_buf_phys + offs + mb_mod_length, c);
353 
354             mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx,
355                      (char *)mbs.mb_buf + offs,
356                      (char *)mbs.mb_buf + offs + mb_mod_length, c);
357             g_free(one_file);
358             tmpl = tmpl->next;
359         }
360         g_list_free(mods);
361     }
362 
363     /* Commandline support */
364     char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
365     snprintf(kcmdline, sizeof(kcmdline), "%s %s",
366              kernel_filename, kernel_cmdline);
367     stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
368 
369     stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));
370 
371     stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys + mbs.offset_mbinfo);
372     stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /* mods_count */
373 
374     /* the kernel is where we want it to be now */
375     stl_p(bootinfo + MBI_FLAGS, MULTIBOOT_FLAGS_MEMORY
376                                 | MULTIBOOT_FLAGS_BOOT_DEVICE
377                                 | MULTIBOOT_FLAGS_CMDLINE
378                                 | MULTIBOOT_FLAGS_MODULES
379                                 | MULTIBOOT_FLAGS_MMAP
380                                 | MULTIBOOT_FLAGS_BOOTLOADER);
381     stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the -boot switch? */
382     stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
383 
384     mb_debug("multiboot: entry_addr = %#x", mh_entry_addr);
385     mb_debug("           mb_buf_phys   = "TARGET_FMT_plx, mbs.mb_buf_phys);
386     mb_debug("           mod_start     = "TARGET_FMT_plx,
387              mbs.mb_buf_phys + mbs.offset_mods);
388     mb_debug("           mb_mods_count = %d", mbs.mb_mods_count);
389 
390     /* save bootinfo off the stack */
391     mb_bootinfo_data = g_memdup(bootinfo, sizeof(bootinfo));
392 
393     /* Pass variables to option rom */
394     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ENTRY, mh_entry_addr);
395     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_load_addr);
396     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, mbs.mb_buf_size);
397     fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA,
398                      mbs.mb_buf, mbs.mb_buf_size);
399 
400     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, ADDR_MBI);
401     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, sizeof(bootinfo));
402     fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, mb_bootinfo_data,
403                      sizeof(bootinfo));
404 
405     option_rom[nb_option_roms].name = "multiboot.bin";
406     option_rom[nb_option_roms].bootindex = 0;
407     nb_option_roms++;
408 
409     return 1; /* yes, we are multiboot */
410 }
411