xref: /openbmc/qemu/hw/i386/multiboot.c (revision 954a6c4f)
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     g_autofree char *kcmdline = NULL;
167 
168     /* Ok, let's see if it is a multiboot image.
169        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
170     for (i = 0; i < (8192 - 48); i += 4) {
171         if (ldl_p(header+i) == 0x1BADB002) {
172             uint32_t checksum = ldl_p(header+i+8);
173             flags = ldl_p(header+i+4);
174             checksum += flags;
175             checksum += (uint32_t)0x1BADB002;
176             if (!checksum) {
177                 is_multiboot = 1;
178                 break;
179             }
180         }
181     }
182 
183     if (!is_multiboot)
184         return 0; /* no multiboot */
185 
186     mb_debug("I believe we found a multiboot image!");
187     memset(bootinfo, 0, sizeof(bootinfo));
188     memset(&mbs, 0, sizeof(mbs));
189 
190     if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
191         error_report("multiboot knows VBE. we don't");
192     }
193     if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
194         uint64_t elf_entry;
195         uint64_t elf_low, elf_high;
196         int kernel_size;
197         fclose(f);
198 
199         if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
200             error_report("Cannot load x86-64 image, give a 32bit one.");
201             exit(1);
202         }
203 
204         kernel_size = load_elf(kernel_filename, NULL, NULL, NULL, &elf_entry,
205                                &elf_low, &elf_high, NULL, 0, I386_ELF_MACHINE,
206                                0, 0);
207         if (kernel_size < 0) {
208             error_report("Error while loading elf kernel");
209             exit(1);
210         }
211         mh_load_addr = elf_low;
212         mb_kernel_size = elf_high - elf_low;
213         mh_entry_addr = elf_entry;
214 
215         mbs.mb_buf = g_malloc(mb_kernel_size);
216         if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
217             error_report("Error while fetching elf kernel from rom");
218             exit(1);
219         }
220 
221         mb_debug("loading multiboot-elf kernel "
222                  "(%#x bytes) with entry %#zx",
223                  mb_kernel_size, (size_t)mh_entry_addr);
224     } else {
225         /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
226         uint32_t mh_header_addr = ldl_p(header+i+12);
227         uint32_t mh_load_end_addr = ldl_p(header+i+20);
228         uint32_t mh_bss_end_addr = ldl_p(header+i+24);
229 
230         mh_load_addr = ldl_p(header+i+16);
231         if (mh_header_addr < mh_load_addr) {
232             error_report("invalid load_addr address");
233             exit(1);
234         }
235         if (mh_header_addr - mh_load_addr > i) {
236             error_report("invalid header_addr address");
237             exit(1);
238         }
239 
240         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
241         uint32_t mb_load_size = 0;
242         mh_entry_addr = ldl_p(header+i+28);
243 
244         if (mh_load_end_addr) {
245             if (mh_load_end_addr < mh_load_addr) {
246                 error_report("invalid load_end_addr address");
247                 exit(1);
248             }
249             mb_load_size = mh_load_end_addr - mh_load_addr;
250         } else {
251             if (kernel_file_size < mb_kernel_text_offset) {
252                 error_report("invalid kernel_file_size");
253                 exit(1);
254             }
255             mb_load_size = kernel_file_size - mb_kernel_text_offset;
256         }
257         if (mb_load_size > UINT32_MAX - mh_load_addr) {
258             error_report("kernel does not fit in address space");
259             exit(1);
260         }
261         if (mh_bss_end_addr) {
262             if (mh_bss_end_addr < (mh_load_addr + mb_load_size)) {
263                 error_report("invalid bss_end_addr address");
264                 exit(1);
265             }
266             mb_kernel_size = mh_bss_end_addr - mh_load_addr;
267         } else {
268             mb_kernel_size = mb_load_size;
269         }
270 
271         mb_debug("multiboot: header_addr = %#x", mh_header_addr);
272         mb_debug("multiboot: load_addr = %#x", mh_load_addr);
273         mb_debug("multiboot: load_end_addr = %#x", mh_load_end_addr);
274         mb_debug("multiboot: bss_end_addr = %#x", mh_bss_end_addr);
275         mb_debug("loading multiboot kernel (%#x bytes) at %#x",
276                  mb_load_size, mh_load_addr);
277 
278         mbs.mb_buf = g_malloc(mb_kernel_size);
279         fseek(f, mb_kernel_text_offset, SEEK_SET);
280         if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
281             error_report("fread() failed");
282             exit(1);
283         }
284         memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
285         fclose(f);
286     }
287 
288     mbs.mb_buf_phys = mh_load_addr;
289 
290     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
291     mbs.offset_mbinfo = mbs.mb_buf_size;
292 
293     /* Calculate space for cmdlines, bootloader name, and mb_mods */
294     cmdline_len = strlen(kernel_filename) + 1;
295     cmdline_len += strlen(kernel_cmdline) + 1;
296     if (initrd_filename) {
297         const char *r = initrd_filename;
298         cmdline_len += strlen(initrd_filename) + 1;
299         while (*r) {
300             char *value;
301             r = get_opt_value(r, &value);
302             mbs.mb_mods_avail++;
303             mods = g_list_append(mods, value);
304             if (*r) {
305                 r++;
306             }
307         }
308     }
309 
310     mbs.mb_buf_size += cmdline_len;
311     mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
312     mbs.mb_buf_size += strlen(bootloader_name) + 1;
313 
314     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
315 
316     /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
317     mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
318     mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
319     mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
320 
321     if (mods) {
322         GList *tmpl = mods;
323         mbs.offset_mods = mbs.mb_buf_size;
324 
325         while (tmpl) {
326             char *next_space;
327             int mb_mod_length;
328             uint32_t offs = mbs.mb_buf_size;
329             char *one_file = tmpl->data;
330 
331             /* if a space comes after the module filename, treat everything
332                after that as parameters */
333             hwaddr c = mb_add_cmdline(&mbs, one_file);
334             next_space = strchr(one_file, ' ');
335             if (next_space) {
336                 *next_space = '\0';
337             }
338             mb_debug("multiboot loading module: %s", one_file);
339             mb_mod_length = get_image_size(one_file);
340             if (mb_mod_length < 0) {
341                 error_report("Failed to open file '%s'", one_file);
342                 exit(1);
343             }
344 
345             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
346             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
347 
348             if (load_image_size(one_file, (unsigned char *)mbs.mb_buf + offs,
349                                 mbs.mb_buf_size - offs) < 0) {
350                 error_report("Error loading file '%s'", one_file);
351                 exit(1);
352             }
353             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
354                        mbs.mb_buf_phys + offs + mb_mod_length, c);
355 
356             mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx,
357                      (char *)mbs.mb_buf + offs,
358                      (char *)mbs.mb_buf + offs + mb_mod_length, c);
359             g_free(one_file);
360             tmpl = tmpl->next;
361         }
362         g_list_free(mods);
363     }
364 
365     /* Commandline support */
366     kcmdline = g_strdup_printf("%s %s", 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     if (multiboot_dma_enabled) {
406         option_rom[nb_option_roms].name = "multiboot_dma.bin";
407     } else {
408         option_rom[nb_option_roms].name = "multiboot.bin";
409     }
410     option_rom[nb_option_roms].bootindex = 0;
411     nb_option_roms++;
412 
413     return 1; /* yes, we are multiboot */
414 }
415