xref: /openbmc/qemu/hw/i386/multiboot.c (revision a443c3e2)
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/nvram/fw_cfg.h"
29 #include "multiboot.h"
30 #include "hw/loader.h"
31 #include "elf.h"
32 #include "sysemu/sysemu.h"
33 #include "qemu/error-report.h"
34 
35 /* Show multiboot debug output */
36 //#define DEBUG_MULTIBOOT
37 
38 #ifdef DEBUG_MULTIBOOT
39 #define mb_debug(a...) error_report(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,
141              s->mb_mods_count, start, end);
142 
143     s->mb_mods_count++;
144 }
145 
146 int load_multiboot(X86MachineState *x86ms,
147                    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     bool multiboot_dma_enabled = X86_MACHINE_GET_CLASS(x86ms)->fwcfg_dma_enabled;
156     int i, is_multiboot = 0;
157     uint32_t flags = 0;
158     uint32_t mh_entry_addr;
159     uint32_t mh_load_addr;
160     uint32_t mb_kernel_size;
161     MultibootState mbs;
162     uint8_t bootinfo[MBI_SIZE];
163     uint8_t *mb_bootinfo_data;
164     uint32_t cmdline_len;
165     GList *mods = NULL;
166 
167     /* Ok, let's see if it is a multiboot image.
168        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
169     for (i = 0; i < (8192 - 48); i += 4) {
170         if (ldl_p(header+i) == 0x1BADB002) {
171             uint32_t checksum = ldl_p(header+i+8);
172             flags = ldl_p(header+i+4);
173             checksum += flags;
174             checksum += (uint32_t)0x1BADB002;
175             if (!checksum) {
176                 is_multiboot = 1;
177                 break;
178             }
179         }
180     }
181 
182     if (!is_multiboot)
183         return 0; /* no multiboot */
184 
185     mb_debug("I believe we found a multiboot image!");
186     memset(bootinfo, 0, sizeof(bootinfo));
187     memset(&mbs, 0, sizeof(mbs));
188 
189     if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
190         error_report("multiboot knows VBE. we don't");
191     }
192     if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
193         uint64_t elf_entry;
194         uint64_t elf_low, elf_high;
195         int kernel_size;
196         fclose(f);
197 
198         if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
199             error_report("Cannot load x86-64 image, give a 32bit one.");
200             exit(1);
201         }
202 
203         kernel_size = load_elf(kernel_filename, NULL, NULL, NULL, &elf_entry,
204                                &elf_low, &elf_high, NULL, 0, I386_ELF_MACHINE,
205                                0, 0);
206         if (kernel_size < 0) {
207             error_report("Error while loading elf kernel");
208             exit(1);
209         }
210         mh_load_addr = elf_low;
211         mb_kernel_size = elf_high - elf_low;
212         mh_entry_addr = elf_entry;
213 
214         mbs.mb_buf = g_malloc(mb_kernel_size);
215         if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
216             error_report("Error while fetching elf kernel from rom");
217             exit(1);
218         }
219 
220         mb_debug("loading multiboot-elf kernel "
221                  "(%#x bytes) with entry %#zx",
222                  mb_kernel_size, (size_t)mh_entry_addr);
223     } else {
224         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
225         uint32_t mh_header_addr = ldl_p(header+i+12);
226         uint32_t mh_load_end_addr = ldl_p(header+i+20);
227         uint32_t mh_bss_end_addr = ldl_p(header+i+24);
228 
229         mh_load_addr = ldl_p(header+i+16);
230         if (mh_header_addr < mh_load_addr) {
231             error_report("invalid load_addr address");
232             exit(1);
233         }
234         if (mh_header_addr - mh_load_addr > i) {
235             error_report("invalid header_addr address");
236             exit(1);
237         }
238 
239         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
240         uint32_t mb_load_size = 0;
241         mh_entry_addr = ldl_p(header+i+28);
242 
243         if (mh_load_end_addr) {
244             if (mh_load_end_addr < mh_load_addr) {
245                 error_report("invalid load_end_addr address");
246                 exit(1);
247             }
248             mb_load_size = mh_load_end_addr - mh_load_addr;
249         } else {
250             if (kernel_file_size < mb_kernel_text_offset) {
251                 error_report("invalid kernel_file_size");
252                 exit(1);
253             }
254             mb_load_size = kernel_file_size - mb_kernel_text_offset;
255         }
256         if (mb_load_size > UINT32_MAX - mh_load_addr) {
257             error_report("kernel does not fit in address space");
258             exit(1);
259         }
260         if (mh_bss_end_addr) {
261             if (mh_bss_end_addr < (mh_load_addr + mb_load_size)) {
262                 error_report("invalid bss_end_addr address");
263                 exit(1);
264             }
265             mb_kernel_size = mh_bss_end_addr - mh_load_addr;
266         } else {
267             mb_kernel_size = mb_load_size;
268         }
269 
270         mb_debug("multiboot: header_addr = %#x", mh_header_addr);
271         mb_debug("multiboot: load_addr = %#x", mh_load_addr);
272         mb_debug("multiboot: load_end_addr = %#x", mh_load_end_addr);
273         mb_debug("multiboot: bss_end_addr = %#x", mh_bss_end_addr);
274         mb_debug("loading multiboot kernel (%#x bytes) at %#x",
275                  mb_load_size, mh_load_addr);
276 
277         mbs.mb_buf = g_malloc(mb_kernel_size);
278         fseek(f, mb_kernel_text_offset, SEEK_SET);
279         if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
280             error_report("fread() failed");
281             exit(1);
282         }
283         memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
284         fclose(f);
285     }
286 
287     mbs.mb_buf_phys = mh_load_addr;
288 
289     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
290     mbs.offset_mbinfo = mbs.mb_buf_size;
291 
292     /* Calculate space for cmdlines, bootloader name, and mb_mods */
293     cmdline_len = strlen(kernel_filename) + 1;
294     cmdline_len += strlen(kernel_cmdline) + 1;
295     if (initrd_filename) {
296         const char *r = initrd_filename;
297         cmdline_len += strlen(initrd_filename) + 1;
298         while (*r) {
299             char *value;
300             r = get_opt_value(r, &value);
301             mbs.mb_mods_avail++;
302             mods = g_list_append(mods, value);
303             if (*r) {
304                 r++;
305             }
306         }
307     }
308 
309     mbs.mb_buf_size += cmdline_len;
310     mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
311     mbs.mb_buf_size += strlen(bootloader_name) + 1;
312 
313     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
314 
315     /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
316     mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
317     mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
318     mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
319 
320     if (mods) {
321         GList *tmpl = mods;
322         mbs.offset_mods = mbs.mb_buf_size;
323 
324         while (tmpl) {
325             char *next_space;
326             int mb_mod_length;
327             uint32_t offs = mbs.mb_buf_size;
328             char *one_file = tmpl->data;
329 
330             /* if a space comes after the module filename, treat everything
331                after that as parameters */
332             hwaddr c = mb_add_cmdline(&mbs, one_file);
333             next_space = strchr(one_file, ' ');
334             if (next_space) {
335                 *next_space = '\0';
336             }
337             mb_debug("multiboot loading module: %s", one_file);
338             mb_mod_length = get_image_size(one_file);
339             if (mb_mod_length < 0) {
340                 error_report("Failed to open file '%s'", one_file);
341                 exit(1);
342             }
343 
344             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
345             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
346 
347             if (load_image_size(one_file, (unsigned char *)mbs.mb_buf + offs,
348                                 mbs.mb_buf_size - offs) < 0) {
349                 error_report("Error loading file '%s'", one_file);
350                 exit(1);
351             }
352             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
353                        mbs.mb_buf_phys + offs + mb_mod_length, c);
354 
355             mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx,
356                      (char *)mbs.mb_buf + offs,
357                      (char *)mbs.mb_buf + offs + mb_mod_length, c);
358             g_free(one_file);
359             tmpl = tmpl->next;
360         }
361         g_list_free(mods);
362     }
363 
364     /* Commandline support */
365     char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
366     snprintf(kcmdline, sizeof(kcmdline), "%s %s",
367              kernel_filename, kernel_cmdline);
368     stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
369 
370     stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));
371 
372     stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys + mbs.offset_mbinfo);
373     stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /* mods_count */
374 
375     /* the kernel is where we want it to be now */
376     stl_p(bootinfo + MBI_FLAGS, MULTIBOOT_FLAGS_MEMORY
377                                 | MULTIBOOT_FLAGS_BOOT_DEVICE
378                                 | MULTIBOOT_FLAGS_CMDLINE
379                                 | MULTIBOOT_FLAGS_MODULES
380                                 | MULTIBOOT_FLAGS_MMAP
381                                 | MULTIBOOT_FLAGS_BOOTLOADER);
382     stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the -boot switch? */
383     stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
384 
385     mb_debug("multiboot: entry_addr = %#x", mh_entry_addr);
386     mb_debug("           mb_buf_phys   = "TARGET_FMT_plx, mbs.mb_buf_phys);
387     mb_debug("           mod_start     = "TARGET_FMT_plx,
388              mbs.mb_buf_phys + mbs.offset_mods);
389     mb_debug("           mb_mods_count = %d", mbs.mb_mods_count);
390 
391     /* save bootinfo off the stack */
392     mb_bootinfo_data = g_memdup(bootinfo, sizeof(bootinfo));
393 
394     /* Pass variables to option rom */
395     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ENTRY, mh_entry_addr);
396     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_load_addr);
397     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, mbs.mb_buf_size);
398     fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA,
399                      mbs.mb_buf, mbs.mb_buf_size);
400 
401     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, ADDR_MBI);
402     fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, sizeof(bootinfo));
403     fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, mb_bootinfo_data,
404                      sizeof(bootinfo));
405 
406     if (multiboot_dma_enabled) {
407         option_rom[nb_option_roms].name = "multiboot_dma.bin";
408     } else {
409         option_rom[nb_option_roms].name = "multiboot.bin";
410     }
411     option_rom[nb_option_roms].bootindex = 0;
412     nb_option_roms++;
413 
414     return 1; /* yes, we are multiboot */
415 }
416