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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * misc.c
4 *
5 * This is a collection of several routines used to extract the kernel
6 * which includes KASLR relocation, decompression, ELF parsing, and
7 * relocation processing. Additionally included are the screen and serial
8 * output functions and related debugging support functions.
9 *
10 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
11 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
12 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
13 */
14
15#include "misc.h"
16#include "error.h"
17#include "pgtable.h"
18#include "../string.h"
19#include "../voffset.h"
20#include <asm/bootparam_utils.h>
21
22/*
23 * WARNING!!
24 * This code is compiled with -fPIC and it is relocated dynamically at
25 * run time, but no relocation processing is performed. This means that
26 * it is not safe to place pointers in static structures.
27 */
28
29/* Macros used by the included decompressor code below. */
30#define STATIC static
31/* Define an externally visible malloc()/free(). */
32#define MALLOC_VISIBLE
33#include <linux/decompress/mm.h>
34
35/*
36 * Provide definitions of memzero and memmove as some of the decompressors will
37 * try to define their own functions if these are not defined as macros.
38 */
39#define memzero(s, n) memset((s), 0, (n))
40#ifndef memmove
41#define memmove memmove
42/* Functions used by the included decompressor code below. */
43void *memmove(void *dest, const void *src, size_t n);
44#endif
45
46/*
47 * This is set up by the setup-routine at boot-time
48 */
49struct boot_params *boot_params_ptr;
50
51struct port_io_ops pio_ops;
52
53memptr free_mem_ptr;
54memptr free_mem_end_ptr;
55int spurious_nmi_count;
56
57static char *vidmem;
58static int vidport;
59
60/* These might be accessed before .bss is cleared, so use .data instead. */
61static int lines __section(".data");
62static int cols __section(".data");
63
64#ifdef CONFIG_KERNEL_GZIP
65#include "../../../../lib/decompress_inflate.c"
66#endif
67
68#ifdef CONFIG_KERNEL_BZIP2
69#include "../../../../lib/decompress_bunzip2.c"
70#endif
71
72#ifdef CONFIG_KERNEL_LZMA
73#include "../../../../lib/decompress_unlzma.c"
74#endif
75
76#ifdef CONFIG_KERNEL_XZ
77#include "../../../../lib/decompress_unxz.c"
78#endif
79
80#ifdef CONFIG_KERNEL_LZO
81#include "../../../../lib/decompress_unlzo.c"
82#endif
83
84#ifdef CONFIG_KERNEL_LZ4
85#include "../../../../lib/decompress_unlz4.c"
86#endif
87
88#ifdef CONFIG_KERNEL_ZSTD
89#include "../../../../lib/decompress_unzstd.c"
90#endif
91/*
92 * NOTE: When adding a new decompressor, please update the analysis in
93 * ../header.S.
94 */
95
96static void scroll(void)
97{
98 int i;
99
100 memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
101 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
102 vidmem[i] = ' ';
103}
104
105#define XMTRDY 0x20
106
107#define TXR 0 /* Transmit register (WRITE) */
108#define LSR 5 /* Line Status */
109static void serial_putchar(int ch)
110{
111 unsigned timeout = 0xffff;
112
113 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
114 cpu_relax();
115
116 outb(ch, early_serial_base + TXR);
117}
118
119void __putstr(const char *s)
120{
121 int x, y, pos;
122 char c;
123
124 if (early_serial_base) {
125 const char *str = s;
126 while (*str) {
127 if (*str == '\n')
128 serial_putchar('\r');
129 serial_putchar(*str++);
130 }
131 }
132
133 if (lines == 0 || cols == 0)
134 return;
135
136 x = boot_params_ptr->screen_info.orig_x;
137 y = boot_params_ptr->screen_info.orig_y;
138
139 while ((c = *s++) != '\0') {
140 if (c == '\n') {
141 x = 0;
142 if (++y >= lines) {
143 scroll();
144 y--;
145 }
146 } else {
147 vidmem[(x + cols * y) * 2] = c;
148 if (++x >= cols) {
149 x = 0;
150 if (++y >= lines) {
151 scroll();
152 y--;
153 }
154 }
155 }
156 }
157
158 boot_params_ptr->screen_info.orig_x = x;
159 boot_params_ptr->screen_info.orig_y = y;
160
161 pos = (x + cols * y) * 2; /* Update cursor position */
162 outb(14, vidport);
163 outb(0xff & (pos >> 9), vidport+1);
164 outb(15, vidport);
165 outb(0xff & (pos >> 1), vidport+1);
166}
167
168static noinline void __putnum(unsigned long value, unsigned int base,
169 int mindig)
170{
171 char buf[8*sizeof(value)+1];
172 char *p;
173
174 p = buf + sizeof(buf);
175 *--p = '\0';
176
177 while (mindig-- > 0 || value) {
178 unsigned char digit = value % base;
179 digit += (digit >= 10) ? ('a'-10) : '0';
180 *--p = digit;
181
182 value /= base;
183 }
184
185 __putstr(p);
186}
187
188void __puthex(unsigned long value)
189{
190 __putnum(value, 16, sizeof(value)*2);
191}
192
193void __putdec(unsigned long value)
194{
195 __putnum(value, 10, 1);
196}
197
198#ifdef CONFIG_X86_NEED_RELOCS
199static void handle_relocations(void *output, unsigned long output_len,
200 unsigned long virt_addr)
201{
202 int *reloc;
203 unsigned long delta, map, ptr;
204 unsigned long min_addr = (unsigned long)output;
205 unsigned long max_addr = min_addr + (VO___bss_start - VO__text);
206
207 /*
208 * Calculate the delta between where vmlinux was linked to load
209 * and where it was actually loaded.
210 */
211 delta = min_addr - LOAD_PHYSICAL_ADDR;
212
213 /*
214 * The kernel contains a table of relocation addresses. Those
215 * addresses have the final load address of the kernel in virtual
216 * memory. We are currently working in the self map. So we need to
217 * create an adjustment for kernel memory addresses to the self map.
218 * This will involve subtracting out the base address of the kernel.
219 */
220 map = delta - __START_KERNEL_map;
221
222 /*
223 * 32-bit always performs relocations. 64-bit relocations are only
224 * needed if KASLR has chosen a different starting address offset
225 * from __START_KERNEL_map.
226 */
227 if (IS_ENABLED(CONFIG_X86_64))
228 delta = virt_addr - LOAD_PHYSICAL_ADDR;
229
230 if (!delta) {
231 debug_putstr("No relocation needed... ");
232 return;
233 }
234 debug_putstr("Performing relocations... ");
235
236 /*
237 * Process relocations: 32 bit relocations first then 64 bit after.
238 * Three sets of binary relocations are added to the end of the kernel
239 * before compression. Each relocation table entry is the kernel
240 * address of the location which needs to be updated stored as a
241 * 32-bit value which is sign extended to 64 bits.
242 *
243 * Format is:
244 *
245 * kernel bits...
246 * 0 - zero terminator for 64 bit relocations
247 * 64 bit relocation repeated
248 * 0 - zero terminator for inverse 32 bit relocations
249 * 32 bit inverse relocation repeated
250 * 0 - zero terminator for 32 bit relocations
251 * 32 bit relocation repeated
252 *
253 * So we work backwards from the end of the decompressed image.
254 */
255 for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
256 long extended = *reloc;
257 extended += map;
258
259 ptr = (unsigned long)extended;
260 if (ptr < min_addr || ptr > max_addr)
261 error("32-bit relocation outside of kernel!\n");
262
263 *(uint32_t *)ptr += delta;
264 }
265#ifdef CONFIG_X86_64
266 while (*--reloc) {
267 long extended = *reloc;
268 extended += map;
269
270 ptr = (unsigned long)extended;
271 if (ptr < min_addr || ptr > max_addr)
272 error("inverse 32-bit relocation outside of kernel!\n");
273
274 *(int32_t *)ptr -= delta;
275 }
276 for (reloc--; *reloc; reloc--) {
277 long extended = *reloc;
278 extended += map;
279
280 ptr = (unsigned long)extended;
281 if (ptr < min_addr || ptr > max_addr)
282 error("64-bit relocation outside of kernel!\n");
283
284 *(uint64_t *)ptr += delta;
285 }
286#endif
287}
288#else
289static inline void handle_relocations(void *output, unsigned long output_len,
290 unsigned long virt_addr)
291{ }
292#endif
293
294static size_t parse_elf(void *output)
295{
296#ifdef CONFIG_X86_64
297 Elf64_Ehdr ehdr;
298 Elf64_Phdr *phdrs, *phdr;
299#else
300 Elf32_Ehdr ehdr;
301 Elf32_Phdr *phdrs, *phdr;
302#endif
303 void *dest;
304 int i;
305
306 memcpy(&ehdr, output, sizeof(ehdr));
307 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
308 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
309 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
310 ehdr.e_ident[EI_MAG3] != ELFMAG3)
311 error("Kernel is not a valid ELF file");
312
313 debug_putstr("Parsing ELF... ");
314
315 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
316 if (!phdrs)
317 error("Failed to allocate space for phdrs");
318
319 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
320
321 for (i = 0; i < ehdr.e_phnum; i++) {
322 phdr = &phdrs[i];
323
324 switch (phdr->p_type) {
325 case PT_LOAD:
326#ifdef CONFIG_X86_64
327 if ((phdr->p_align % 0x200000) != 0)
328 error("Alignment of LOAD segment isn't multiple of 2MB");
329#endif
330#ifdef CONFIG_RELOCATABLE
331 dest = output;
332 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
333#else
334 dest = (void *)(phdr->p_paddr);
335#endif
336 memmove(dest, output + phdr->p_offset, phdr->p_filesz);
337 break;
338 default: /* Ignore other PT_* */ break;
339 }
340 }
341
342 free(phdrs);
343
344 return ehdr.e_entry - LOAD_PHYSICAL_ADDR;
345}
346
347const unsigned long kernel_text_size = VO___start_rodata - VO__text;
348const unsigned long kernel_total_size = VO__end - VO__text;
349
350static u8 boot_heap[BOOT_HEAP_SIZE] __aligned(4);
351
352extern unsigned char input_data[];
353extern unsigned int input_len, output_len;
354
355unsigned long decompress_kernel(unsigned char *outbuf, unsigned long virt_addr,
356 void (*error)(char *x))
357{
358 unsigned long entry;
359
360 if (!free_mem_ptr) {
361 free_mem_ptr = (unsigned long)boot_heap;
362 free_mem_end_ptr = (unsigned long)boot_heap + sizeof(boot_heap);
363 }
364
365 if (__decompress(input_data, input_len, NULL, NULL, outbuf, output_len,
366 NULL, error) < 0)
367 return ULONG_MAX;
368
369 entry = parse_elf(outbuf);
370 handle_relocations(outbuf, output_len, virt_addr);
371
372 return entry;
373}
374
375/*
376 * Set the memory encryption xloadflag based on the mem_encrypt= command line
377 * parameter, if provided.
378 */
379static void parse_mem_encrypt(struct setup_header *hdr)
380{
381 int on = cmdline_find_option_bool("mem_encrypt=on");
382 int off = cmdline_find_option_bool("mem_encrypt=off");
383
384 if (on > off)
385 hdr->xloadflags |= XLF_MEM_ENCRYPTION;
386}
387
388static void early_sev_detect(void)
389{
390 /*
391 * Accessing video memory causes guest termination because
392 * the boot stage2 #VC handler of SEV-ES/SNP guests does not
393 * support MMIO handling and kexec -c adds screen_info to the
394 * boot parameters passed to the kexec kernel, which causes
395 * console output to be dumped to both video and serial.
396 */
397 if (sev_status & MSR_AMD64_SEV_ES_ENABLED)
398 lines = cols = 0;
399}
400
401/*
402 * The compressed kernel image (ZO), has been moved so that its position
403 * is against the end of the buffer used to hold the uncompressed kernel
404 * image (VO) and the execution environment (.bss, .brk), which makes sure
405 * there is room to do the in-place decompression. (See header.S for the
406 * calculations.)
407 *
408 * |-----compressed kernel image------|
409 * V V
410 * 0 extract_offset +INIT_SIZE
411 * |-----------|---------------|-------------------------|--------|
412 * | | | |
413 * VO__text startup_32 of ZO VO__end ZO__end
414 * ^ ^
415 * |-------uncompressed kernel image---------|
416 *
417 */
418asmlinkage __visible void *extract_kernel(void *rmode, unsigned char *output)
419{
420 unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
421 memptr heap = (memptr)boot_heap;
422 unsigned long needed_size;
423 size_t entry_offset;
424
425 /* Retain x86 boot parameters pointer passed from startup_32/64. */
426 boot_params_ptr = rmode;
427
428 /* Clear flags intended for solely in-kernel use. */
429 boot_params_ptr->hdr.loadflags &= ~KASLR_FLAG;
430
431 parse_mem_encrypt(&boot_params_ptr->hdr);
432
433 sanitize_boot_params(boot_params_ptr);
434
435 if (boot_params_ptr->screen_info.orig_video_mode == 7) {
436 vidmem = (char *) 0xb0000;
437 vidport = 0x3b4;
438 } else {
439 vidmem = (char *) 0xb8000;
440 vidport = 0x3d4;
441 }
442
443 lines = boot_params_ptr->screen_info.orig_video_lines;
444 cols = boot_params_ptr->screen_info.orig_video_cols;
445
446 init_default_io_ops();
447
448 /*
449 * Detect TDX guest environment.
450 *
451 * It has to be done before console_init() in order to use
452 * paravirtualized port I/O operations if needed.
453 */
454 early_tdx_detect();
455
456 early_sev_detect();
457
458 console_init();
459
460 /*
461 * Save RSDP address for later use. Have this after console_init()
462 * so that early debugging output from the RSDP parsing code can be
463 * collected.
464 */
465 boot_params_ptr->acpi_rsdp_addr = get_rsdp_addr();
466
467 debug_putstr("early console in extract_kernel\n");
468
469 free_mem_ptr = heap; /* Heap */
470 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
471
472 /*
473 * The memory hole needed for the kernel is the larger of either
474 * the entire decompressed kernel plus relocation table, or the
475 * entire decompressed kernel plus .bss and .brk sections.
476 *
477 * On X86_64, the memory is mapped with PMD pages. Round the
478 * size up so that the full extent of PMD pages mapped is
479 * included in the check against the valid memory table
480 * entries. This ensures the full mapped area is usable RAM
481 * and doesn't include any reserved areas.
482 */
483 needed_size = max_t(unsigned long, output_len, kernel_total_size);
484#ifdef CONFIG_X86_64
485 needed_size = ALIGN(needed_size, MIN_KERNEL_ALIGN);
486#endif
487
488 /* Report initial kernel position details. */
489 debug_putaddr(input_data);
490 debug_putaddr(input_len);
491 debug_putaddr(output);
492 debug_putaddr(output_len);
493 debug_putaddr(kernel_total_size);
494 debug_putaddr(needed_size);
495
496#ifdef CONFIG_X86_64
497 /* Report address of 32-bit trampoline */
498 debug_putaddr(trampoline_32bit);
499#endif
500
501 choose_random_location((unsigned long)input_data, input_len,
502 (unsigned long *)&output,
503 needed_size,
504 &virt_addr);
505
506 /* Validate memory location choices. */
507 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
508 error("Destination physical address inappropriately aligned");
509 if (virt_addr & (MIN_KERNEL_ALIGN - 1))
510 error("Destination virtual address inappropriately aligned");
511#ifdef CONFIG_X86_64
512 if (heap > 0x3fffffffffffUL)
513 error("Destination address too large");
514 if (virt_addr + needed_size > KERNEL_IMAGE_SIZE)
515 error("Destination virtual address is beyond the kernel mapping area");
516#else
517 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
518 error("Destination address too large");
519#endif
520#ifndef CONFIG_RELOCATABLE
521 if (virt_addr != LOAD_PHYSICAL_ADDR)
522 error("Destination virtual address changed when not relocatable");
523#endif
524
525 debug_putstr("\nDecompressing Linux... ");
526
527 if (init_unaccepted_memory()) {
528 debug_putstr("Accepting memory... ");
529 accept_memory(__pa(output), needed_size);
530 }
531
532 entry_offset = decompress_kernel(output, virt_addr, error);
533
534 debug_putstr("done.\nBooting the kernel (entry_offset: 0x");
535 debug_puthex(entry_offset);
536 debug_putstr(").\n");
537
538 /* Disable exception handling before booting the kernel */
539 cleanup_exception_handling();
540
541 if (spurious_nmi_count) {
542 error_putstr("Spurious early NMIs ignored: ");
543 error_putdec(spurious_nmi_count);
544 error_putstr("\n");
545 }
546
547 return output + entry_offset;
548}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * misc.c
4 *
5 * This is a collection of several routines used to extract the kernel
6 * which includes KASLR relocation, decompression, ELF parsing, and
7 * relocation processing. Additionally included are the screen and serial
8 * output functions and related debugging support functions.
9 *
10 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
11 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
12 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
13 */
14
15#include "misc.h"
16#include "error.h"
17#include "pgtable.h"
18#include "../string.h"
19#include "../voffset.h"
20#include <asm/bootparam_utils.h>
21
22/*
23 * WARNING!!
24 * This code is compiled with -fPIC and it is relocated dynamically at
25 * run time, but no relocation processing is performed. This means that
26 * it is not safe to place pointers in static structures.
27 */
28
29/* Macros used by the included decompressor code below. */
30#define STATIC static
31/* Define an externally visible malloc()/free(). */
32#define MALLOC_VISIBLE
33#include <linux/decompress/mm.h>
34
35/*
36 * Provide definitions of memzero and memmove as some of the decompressors will
37 * try to define their own functions if these are not defined as macros.
38 */
39#define memzero(s, n) memset((s), 0, (n))
40#ifndef memmove
41#define memmove memmove
42/* Functions used by the included decompressor code below. */
43void *memmove(void *dest, const void *src, size_t n);
44#endif
45
46/*
47 * This is set up by the setup-routine at boot-time
48 */
49struct boot_params *boot_params_ptr;
50
51struct port_io_ops pio_ops;
52
53memptr free_mem_ptr;
54memptr free_mem_end_ptr;
55
56static char *vidmem;
57static int vidport;
58
59/* These might be accessed before .bss is cleared, so use .data instead. */
60static int lines __section(".data");
61static int cols __section(".data");
62
63#ifdef CONFIG_KERNEL_GZIP
64#include "../../../../lib/decompress_inflate.c"
65#endif
66
67#ifdef CONFIG_KERNEL_BZIP2
68#include "../../../../lib/decompress_bunzip2.c"
69#endif
70
71#ifdef CONFIG_KERNEL_LZMA
72#include "../../../../lib/decompress_unlzma.c"
73#endif
74
75#ifdef CONFIG_KERNEL_XZ
76#include "../../../../lib/decompress_unxz.c"
77#endif
78
79#ifdef CONFIG_KERNEL_LZO
80#include "../../../../lib/decompress_unlzo.c"
81#endif
82
83#ifdef CONFIG_KERNEL_LZ4
84#include "../../../../lib/decompress_unlz4.c"
85#endif
86
87#ifdef CONFIG_KERNEL_ZSTD
88#include "../../../../lib/decompress_unzstd.c"
89#endif
90/*
91 * NOTE: When adding a new decompressor, please update the analysis in
92 * ../header.S.
93 */
94
95static void scroll(void)
96{
97 int i;
98
99 memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
100 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
101 vidmem[i] = ' ';
102}
103
104#define XMTRDY 0x20
105
106#define TXR 0 /* Transmit register (WRITE) */
107#define LSR 5 /* Line Status */
108static void serial_putchar(int ch)
109{
110 unsigned timeout = 0xffff;
111
112 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
113 cpu_relax();
114
115 outb(ch, early_serial_base + TXR);
116}
117
118void __putstr(const char *s)
119{
120 int x, y, pos;
121 char c;
122
123 if (early_serial_base) {
124 const char *str = s;
125 while (*str) {
126 if (*str == '\n')
127 serial_putchar('\r');
128 serial_putchar(*str++);
129 }
130 }
131
132 if (lines == 0 || cols == 0)
133 return;
134
135 x = boot_params_ptr->screen_info.orig_x;
136 y = boot_params_ptr->screen_info.orig_y;
137
138 while ((c = *s++) != '\0') {
139 if (c == '\n') {
140 x = 0;
141 if (++y >= lines) {
142 scroll();
143 y--;
144 }
145 } else {
146 vidmem[(x + cols * y) * 2] = c;
147 if (++x >= cols) {
148 x = 0;
149 if (++y >= lines) {
150 scroll();
151 y--;
152 }
153 }
154 }
155 }
156
157 boot_params_ptr->screen_info.orig_x = x;
158 boot_params_ptr->screen_info.orig_y = y;
159
160 pos = (x + cols * y) * 2; /* Update cursor position */
161 outb(14, vidport);
162 outb(0xff & (pos >> 9), vidport+1);
163 outb(15, vidport);
164 outb(0xff & (pos >> 1), vidport+1);
165}
166
167void __puthex(unsigned long value)
168{
169 char alpha[2] = "0";
170 int bits;
171
172 for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
173 unsigned long digit = (value >> bits) & 0xf;
174
175 if (digit < 0xA)
176 alpha[0] = '0' + digit;
177 else
178 alpha[0] = 'a' + (digit - 0xA);
179
180 __putstr(alpha);
181 }
182}
183
184#ifdef CONFIG_X86_NEED_RELOCS
185static void handle_relocations(void *output, unsigned long output_len,
186 unsigned long virt_addr)
187{
188 int *reloc;
189 unsigned long delta, map, ptr;
190 unsigned long min_addr = (unsigned long)output;
191 unsigned long max_addr = min_addr + (VO___bss_start - VO__text);
192
193 /*
194 * Calculate the delta between where vmlinux was linked to load
195 * and where it was actually loaded.
196 */
197 delta = min_addr - LOAD_PHYSICAL_ADDR;
198
199 /*
200 * The kernel contains a table of relocation addresses. Those
201 * addresses have the final load address of the kernel in virtual
202 * memory. We are currently working in the self map. So we need to
203 * create an adjustment for kernel memory addresses to the self map.
204 * This will involve subtracting out the base address of the kernel.
205 */
206 map = delta - __START_KERNEL_map;
207
208 /*
209 * 32-bit always performs relocations. 64-bit relocations are only
210 * needed if KASLR has chosen a different starting address offset
211 * from __START_KERNEL_map.
212 */
213 if (IS_ENABLED(CONFIG_X86_64))
214 delta = virt_addr - LOAD_PHYSICAL_ADDR;
215
216 if (!delta) {
217 debug_putstr("No relocation needed... ");
218 return;
219 }
220 debug_putstr("Performing relocations... ");
221
222 /*
223 * Process relocations: 32 bit relocations first then 64 bit after.
224 * Three sets of binary relocations are added to the end of the kernel
225 * before compression. Each relocation table entry is the kernel
226 * address of the location which needs to be updated stored as a
227 * 32-bit value which is sign extended to 64 bits.
228 *
229 * Format is:
230 *
231 * kernel bits...
232 * 0 - zero terminator for 64 bit relocations
233 * 64 bit relocation repeated
234 * 0 - zero terminator for inverse 32 bit relocations
235 * 32 bit inverse relocation repeated
236 * 0 - zero terminator for 32 bit relocations
237 * 32 bit relocation repeated
238 *
239 * So we work backwards from the end of the decompressed image.
240 */
241 for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
242 long extended = *reloc;
243 extended += map;
244
245 ptr = (unsigned long)extended;
246 if (ptr < min_addr || ptr > max_addr)
247 error("32-bit relocation outside of kernel!\n");
248
249 *(uint32_t *)ptr += delta;
250 }
251#ifdef CONFIG_X86_64
252 while (*--reloc) {
253 long extended = *reloc;
254 extended += map;
255
256 ptr = (unsigned long)extended;
257 if (ptr < min_addr || ptr > max_addr)
258 error("inverse 32-bit relocation outside of kernel!\n");
259
260 *(int32_t *)ptr -= delta;
261 }
262 for (reloc--; *reloc; reloc--) {
263 long extended = *reloc;
264 extended += map;
265
266 ptr = (unsigned long)extended;
267 if (ptr < min_addr || ptr > max_addr)
268 error("64-bit relocation outside of kernel!\n");
269
270 *(uint64_t *)ptr += delta;
271 }
272#endif
273}
274#else
275static inline void handle_relocations(void *output, unsigned long output_len,
276 unsigned long virt_addr)
277{ }
278#endif
279
280static size_t parse_elf(void *output)
281{
282#ifdef CONFIG_X86_64
283 Elf64_Ehdr ehdr;
284 Elf64_Phdr *phdrs, *phdr;
285#else
286 Elf32_Ehdr ehdr;
287 Elf32_Phdr *phdrs, *phdr;
288#endif
289 void *dest;
290 int i;
291
292 memcpy(&ehdr, output, sizeof(ehdr));
293 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
294 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
295 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
296 ehdr.e_ident[EI_MAG3] != ELFMAG3)
297 error("Kernel is not a valid ELF file");
298
299 debug_putstr("Parsing ELF... ");
300
301 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
302 if (!phdrs)
303 error("Failed to allocate space for phdrs");
304
305 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
306
307 for (i = 0; i < ehdr.e_phnum; i++) {
308 phdr = &phdrs[i];
309
310 switch (phdr->p_type) {
311 case PT_LOAD:
312#ifdef CONFIG_X86_64
313 if ((phdr->p_align % 0x200000) != 0)
314 error("Alignment of LOAD segment isn't multiple of 2MB");
315#endif
316#ifdef CONFIG_RELOCATABLE
317 dest = output;
318 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
319#else
320 dest = (void *)(phdr->p_paddr);
321#endif
322 memmove(dest, output + phdr->p_offset, phdr->p_filesz);
323 break;
324 default: /* Ignore other PT_* */ break;
325 }
326 }
327
328 free(phdrs);
329
330 return ehdr.e_entry - LOAD_PHYSICAL_ADDR;
331}
332
333const unsigned long kernel_total_size = VO__end - VO__text;
334
335static u8 boot_heap[BOOT_HEAP_SIZE] __aligned(4);
336
337extern unsigned char input_data[];
338extern unsigned int input_len, output_len;
339
340unsigned long decompress_kernel(unsigned char *outbuf, unsigned long virt_addr,
341 void (*error)(char *x))
342{
343 unsigned long entry;
344
345 if (!free_mem_ptr) {
346 free_mem_ptr = (unsigned long)boot_heap;
347 free_mem_end_ptr = (unsigned long)boot_heap + sizeof(boot_heap);
348 }
349
350 if (__decompress(input_data, input_len, NULL, NULL, outbuf, output_len,
351 NULL, error) < 0)
352 return ULONG_MAX;
353
354 entry = parse_elf(outbuf);
355 handle_relocations(outbuf, output_len, virt_addr);
356
357 return entry;
358}
359
360/*
361 * The compressed kernel image (ZO), has been moved so that its position
362 * is against the end of the buffer used to hold the uncompressed kernel
363 * image (VO) and the execution environment (.bss, .brk), which makes sure
364 * there is room to do the in-place decompression. (See header.S for the
365 * calculations.)
366 *
367 * |-----compressed kernel image------|
368 * V V
369 * 0 extract_offset +INIT_SIZE
370 * |-----------|---------------|-------------------------|--------|
371 * | | | |
372 * VO__text startup_32 of ZO VO__end ZO__end
373 * ^ ^
374 * |-------uncompressed kernel image---------|
375 *
376 */
377asmlinkage __visible void *extract_kernel(void *rmode, unsigned char *output)
378{
379 unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
380 memptr heap = (memptr)boot_heap;
381 unsigned long needed_size;
382 size_t entry_offset;
383
384 /* Retain x86 boot parameters pointer passed from startup_32/64. */
385 boot_params_ptr = rmode;
386
387 /* Clear flags intended for solely in-kernel use. */
388 boot_params_ptr->hdr.loadflags &= ~KASLR_FLAG;
389
390 sanitize_boot_params(boot_params_ptr);
391
392 if (boot_params_ptr->screen_info.orig_video_mode == 7) {
393 vidmem = (char *) 0xb0000;
394 vidport = 0x3b4;
395 } else {
396 vidmem = (char *) 0xb8000;
397 vidport = 0x3d4;
398 }
399
400 lines = boot_params_ptr->screen_info.orig_video_lines;
401 cols = boot_params_ptr->screen_info.orig_video_cols;
402
403 init_default_io_ops();
404
405 /*
406 * Detect TDX guest environment.
407 *
408 * It has to be done before console_init() in order to use
409 * paravirtualized port I/O operations if needed.
410 */
411 early_tdx_detect();
412
413 console_init();
414
415 /*
416 * Save RSDP address for later use. Have this after console_init()
417 * so that early debugging output from the RSDP parsing code can be
418 * collected.
419 */
420 boot_params_ptr->acpi_rsdp_addr = get_rsdp_addr();
421
422 debug_putstr("early console in extract_kernel\n");
423
424 free_mem_ptr = heap; /* Heap */
425 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
426
427 /*
428 * The memory hole needed for the kernel is the larger of either
429 * the entire decompressed kernel plus relocation table, or the
430 * entire decompressed kernel plus .bss and .brk sections.
431 *
432 * On X86_64, the memory is mapped with PMD pages. Round the
433 * size up so that the full extent of PMD pages mapped is
434 * included in the check against the valid memory table
435 * entries. This ensures the full mapped area is usable RAM
436 * and doesn't include any reserved areas.
437 */
438 needed_size = max_t(unsigned long, output_len, kernel_total_size);
439#ifdef CONFIG_X86_64
440 needed_size = ALIGN(needed_size, MIN_KERNEL_ALIGN);
441#endif
442
443 /* Report initial kernel position details. */
444 debug_putaddr(input_data);
445 debug_putaddr(input_len);
446 debug_putaddr(output);
447 debug_putaddr(output_len);
448 debug_putaddr(kernel_total_size);
449 debug_putaddr(needed_size);
450
451#ifdef CONFIG_X86_64
452 /* Report address of 32-bit trampoline */
453 debug_putaddr(trampoline_32bit);
454#endif
455
456 choose_random_location((unsigned long)input_data, input_len,
457 (unsigned long *)&output,
458 needed_size,
459 &virt_addr);
460
461 /* Validate memory location choices. */
462 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
463 error("Destination physical address inappropriately aligned");
464 if (virt_addr & (MIN_KERNEL_ALIGN - 1))
465 error("Destination virtual address inappropriately aligned");
466#ifdef CONFIG_X86_64
467 if (heap > 0x3fffffffffffUL)
468 error("Destination address too large");
469 if (virt_addr + needed_size > KERNEL_IMAGE_SIZE)
470 error("Destination virtual address is beyond the kernel mapping area");
471#else
472 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
473 error("Destination address too large");
474#endif
475#ifndef CONFIG_RELOCATABLE
476 if (virt_addr != LOAD_PHYSICAL_ADDR)
477 error("Destination virtual address changed when not relocatable");
478#endif
479
480 debug_putstr("\nDecompressing Linux... ");
481
482 if (init_unaccepted_memory()) {
483 debug_putstr("Accepting memory... ");
484 accept_memory(__pa(output), __pa(output) + needed_size);
485 }
486
487 entry_offset = decompress_kernel(output, virt_addr, error);
488
489 debug_putstr("done.\nBooting the kernel (entry_offset: 0x");
490 debug_puthex(entry_offset);
491 debug_putstr(").\n");
492
493 /* Disable exception handling before booting the kernel */
494 cleanup_exception_handling();
495
496 return output + entry_offset;
497}
498
499void fortify_panic(const char *name)
500{
501 error("detected buffer overflow");
502}