xref: /openbmc/u-boot/arch/sandbox/cpu/os.c (revision d94604d5)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2011 The Chromium OS Authors.
4  */
5 
6 #include <dirent.h>
7 #include <errno.h>
8 #include <fcntl.h>
9 #include <getopt.h>
10 #include <setjmp.h>
11 #include <stdio.h>
12 #include <stdint.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <termios.h>
16 #include <time.h>
17 #include <unistd.h>
18 #include <sys/mman.h>
19 #include <sys/stat.h>
20 #include <sys/time.h>
21 #include <sys/types.h>
22 #include <linux/types.h>
23 
24 #include <asm/getopt.h>
25 #include <asm/sections.h>
26 #include <asm/state.h>
27 #include <os.h>
28 #include <rtc_def.h>
29 
30 /* Operating System Interface */
31 
32 struct os_mem_hdr {
33 	size_t length;		/* number of bytes in the block */
34 };
35 
os_read(int fd,void * buf,size_t count)36 ssize_t os_read(int fd, void *buf, size_t count)
37 {
38 	return read(fd, buf, count);
39 }
40 
os_write(int fd,const void * buf,size_t count)41 ssize_t os_write(int fd, const void *buf, size_t count)
42 {
43 	return write(fd, buf, count);
44 }
45 
os_lseek(int fd,off_t offset,int whence)46 off_t os_lseek(int fd, off_t offset, int whence)
47 {
48 	if (whence == OS_SEEK_SET)
49 		whence = SEEK_SET;
50 	else if (whence == OS_SEEK_CUR)
51 		whence = SEEK_CUR;
52 	else if (whence == OS_SEEK_END)
53 		whence = SEEK_END;
54 	else
55 		os_exit(1);
56 	return lseek(fd, offset, whence);
57 }
58 
os_open(const char * pathname,int os_flags)59 int os_open(const char *pathname, int os_flags)
60 {
61 	int flags;
62 
63 	switch (os_flags & OS_O_MASK) {
64 	case OS_O_RDONLY:
65 	default:
66 		flags = O_RDONLY;
67 		break;
68 
69 	case OS_O_WRONLY:
70 		flags = O_WRONLY;
71 		break;
72 
73 	case OS_O_RDWR:
74 		flags = O_RDWR;
75 		break;
76 	}
77 
78 	if (os_flags & OS_O_CREAT)
79 		flags |= O_CREAT;
80 	if (os_flags & OS_O_TRUNC)
81 		flags |= O_TRUNC;
82 
83 	return open(pathname, flags, 0777);
84 }
85 
os_close(int fd)86 int os_close(int fd)
87 {
88 	return close(fd);
89 }
90 
os_unlink(const char * pathname)91 int os_unlink(const char *pathname)
92 {
93 	return unlink(pathname);
94 }
95 
os_exit(int exit_code)96 void os_exit(int exit_code)
97 {
98 	exit(exit_code);
99 }
100 
os_write_file(const char * fname,const void * buf,int size)101 int os_write_file(const char *fname, const void *buf, int size)
102 {
103 	int fd;
104 
105 	fd = os_open(fname, OS_O_WRONLY | OS_O_CREAT | OS_O_TRUNC);
106 	if (fd < 0) {
107 		printf("Cannot open file '%s'\n", fname);
108 		return -EIO;
109 	}
110 	if (os_write(fd, buf, size) != size) {
111 		printf("Cannot write to file '%s'\n", fname);
112 		os_close(fd);
113 		return -EIO;
114 	}
115 	os_close(fd);
116 
117 	return 0;
118 }
119 
os_read_file(const char * fname,void ** bufp,int * sizep)120 int os_read_file(const char *fname, void **bufp, int *sizep)
121 {
122 	off_t size;
123 	int ret = -EIO;
124 	int fd;
125 
126 	fd = os_open(fname, OS_O_RDONLY);
127 	if (fd < 0) {
128 		printf("Cannot open file '%s'\n", fname);
129 		goto err;
130 	}
131 	size = os_lseek(fd, 0, OS_SEEK_END);
132 	if (size < 0) {
133 		printf("Cannot seek to end of file '%s'\n", fname);
134 		goto err;
135 	}
136 	if (os_lseek(fd, 0, OS_SEEK_SET) < 0) {
137 		printf("Cannot seek to start of file '%s'\n", fname);
138 		goto err;
139 	}
140 	*bufp = os_malloc(size);
141 	if (!*bufp) {
142 		printf("Not enough memory to read file '%s'\n", fname);
143 		ret = -ENOMEM;
144 		goto err;
145 	}
146 	if (os_read(fd, *bufp, size) != size) {
147 		printf("Cannot read from file '%s'\n", fname);
148 		goto err;
149 	}
150 	os_close(fd);
151 	*sizep = size;
152 
153 	return 0;
154 err:
155 	os_close(fd);
156 	return ret;
157 }
158 
159 /* Restore tty state when we exit */
160 static struct termios orig_term;
161 static bool term_setup;
162 static bool term_nonblock;
163 
os_fd_restore(void)164 void os_fd_restore(void)
165 {
166 	if (term_setup) {
167 		int flags;
168 
169 		tcsetattr(0, TCSANOW, &orig_term);
170 		if (term_nonblock) {
171 			flags = fcntl(0, F_GETFL, 0);
172 			fcntl(0, F_SETFL, flags & ~O_NONBLOCK);
173 		}
174 		term_setup = false;
175 	}
176 }
177 
178 /* Put tty into raw mode so <tab> and <ctrl+c> work */
os_tty_raw(int fd,bool allow_sigs)179 void os_tty_raw(int fd, bool allow_sigs)
180 {
181 	struct termios term;
182 	int flags;
183 
184 	if (term_setup)
185 		return;
186 
187 	/* If not a tty, don't complain */
188 	if (tcgetattr(fd, &orig_term))
189 		return;
190 
191 	term = orig_term;
192 	term.c_iflag = IGNBRK | IGNPAR;
193 	term.c_oflag = OPOST | ONLCR;
194 	term.c_cflag = CS8 | CREAD | CLOCAL;
195 	term.c_lflag = allow_sigs ? ISIG : 0;
196 	if (tcsetattr(fd, TCSANOW, &term))
197 		return;
198 
199 	flags = fcntl(fd, F_GETFL, 0);
200 	if (!(flags & O_NONBLOCK)) {
201 		if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
202 			return;
203 		term_nonblock = true;
204 	}
205 
206 	term_setup = true;
207 	atexit(os_fd_restore);
208 }
209 
os_malloc(size_t length)210 void *os_malloc(size_t length)
211 {
212 	struct os_mem_hdr *hdr;
213 	int page_size = getpagesize();
214 
215 	/*
216 	 * Use an address that is hopefully available to us so that pointers
217 	 * to this memory are fairly obvious. If we end up with a different
218 	 * address, that's fine too.
219 	 */
220 	hdr = mmap((void *)0x10000000, length + page_size,
221 		   PROT_READ | PROT_WRITE | PROT_EXEC,
222 		   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
223 	if (hdr == MAP_FAILED)
224 		return NULL;
225 	hdr->length = length;
226 
227 	return (void *)hdr + page_size;
228 }
229 
os_free(void * ptr)230 void os_free(void *ptr)
231 {
232 	struct os_mem_hdr *hdr = ptr;
233 
234 	hdr--;
235 	if (ptr)
236 		munmap(hdr, hdr->length + sizeof(*hdr));
237 }
238 
os_realloc(void * ptr,size_t length)239 void *os_realloc(void *ptr, size_t length)
240 {
241 	struct os_mem_hdr *hdr = ptr;
242 	void *buf = NULL;
243 
244 	hdr--;
245 	if (length != 0) {
246 		buf = os_malloc(length);
247 		if (!buf)
248 			return buf;
249 		if (ptr) {
250 			if (length > hdr->length)
251 				length = hdr->length;
252 			memcpy(buf, ptr, length);
253 		}
254 	}
255 	os_free(ptr);
256 
257 	return buf;
258 }
259 
os_usleep(unsigned long usec)260 void os_usleep(unsigned long usec)
261 {
262 	usleep(usec);
263 }
264 
os_get_nsec(void)265 uint64_t __attribute__((no_instrument_function)) os_get_nsec(void)
266 {
267 #if defined(CLOCK_MONOTONIC) && defined(_POSIX_MONOTONIC_CLOCK)
268 	struct timespec tp;
269 	if (EINVAL == clock_gettime(CLOCK_MONOTONIC, &tp)) {
270 		struct timeval tv;
271 
272 		gettimeofday(&tv, NULL);
273 		tp.tv_sec = tv.tv_sec;
274 		tp.tv_nsec = tv.tv_usec * 1000;
275 	}
276 	return tp.tv_sec * 1000000000ULL + tp.tv_nsec;
277 #else
278 	struct timeval tv;
279 	gettimeofday(&tv, NULL);
280 	return tv.tv_sec * 1000000000ULL + tv.tv_usec * 1000;
281 #endif
282 }
283 
284 static char *short_opts;
285 static struct option *long_opts;
286 
os_parse_args(struct sandbox_state * state,int argc,char * argv[])287 int os_parse_args(struct sandbox_state *state, int argc, char *argv[])
288 {
289 	struct sandbox_cmdline_option **sb_opt = __u_boot_sandbox_option_start;
290 	size_t num_options = __u_boot_sandbox_option_count();
291 	size_t i;
292 
293 	int hidden_short_opt;
294 	size_t si;
295 
296 	int c;
297 
298 	if (short_opts || long_opts)
299 		return 1;
300 
301 	state->argc = argc;
302 	state->argv = argv;
303 
304 	/* dynamically construct the arguments to the system getopt_long */
305 	short_opts = os_malloc(sizeof(*short_opts) * num_options * 2 + 1);
306 	long_opts = os_malloc(sizeof(*long_opts) * num_options);
307 	if (!short_opts || !long_opts)
308 		return 1;
309 
310 	/*
311 	 * getopt_long requires "val" to be unique (since that is what the
312 	 * func returns), so generate unique values automatically for flags
313 	 * that don't have a short option.  pick 0x100 as that is above the
314 	 * single byte range (where ASCII/ISO-XXXX-X charsets live).
315 	 */
316 	hidden_short_opt = 0x100;
317 	si = 0;
318 	for (i = 0; i < num_options; ++i) {
319 		long_opts[i].name = sb_opt[i]->flag;
320 		long_opts[i].has_arg = sb_opt[i]->has_arg ?
321 			required_argument : no_argument;
322 		long_opts[i].flag = NULL;
323 
324 		if (sb_opt[i]->flag_short) {
325 			short_opts[si++] = long_opts[i].val = sb_opt[i]->flag_short;
326 			if (long_opts[i].has_arg == required_argument)
327 				short_opts[si++] = ':';
328 		} else
329 			long_opts[i].val = sb_opt[i]->flag_short = hidden_short_opt++;
330 	}
331 	short_opts[si] = '\0';
332 
333 	/* we need to handle output ourselves since u-boot provides printf */
334 	opterr = 0;
335 
336 	/*
337 	 * walk all of the options the user gave us on the command line,
338 	 * figure out what u-boot option structure they belong to (via
339 	 * the unique short val key), and call the appropriate callback.
340 	 */
341 	while ((c = getopt_long(argc, argv, short_opts, long_opts, NULL)) != -1) {
342 		for (i = 0; i < num_options; ++i) {
343 			if (sb_opt[i]->flag_short == c) {
344 				if (sb_opt[i]->callback(state, optarg)) {
345 					state->parse_err = sb_opt[i]->flag;
346 					return 0;
347 				}
348 				break;
349 			}
350 		}
351 		if (i == num_options) {
352 			/*
353 			 * store the faulting flag for later display.  we have to
354 			 * store the flag itself as the getopt parsing itself is
355 			 * tricky: need to handle the following flags (assume all
356 			 * of the below are unknown):
357 			 *   -a        optopt='a' optind=<next>
358 			 *   -abbbb    optopt='a' optind=<this>
359 			 *   -aaaaa    optopt='a' optind=<this>
360 			 *   --a       optopt=0   optind=<this>
361 			 * as you can see, it is impossible to determine the exact
362 			 * faulting flag without doing the parsing ourselves, so
363 			 * we just report the specific flag that failed.
364 			 */
365 			if (optopt) {
366 				static char parse_err[3] = { '-', 0, '\0', };
367 				parse_err[1] = optopt;
368 				state->parse_err = parse_err;
369 			} else
370 				state->parse_err = argv[optind - 1];
371 			break;
372 		}
373 	}
374 
375 	return 0;
376 }
377 
os_dirent_free(struct os_dirent_node * node)378 void os_dirent_free(struct os_dirent_node *node)
379 {
380 	struct os_dirent_node *next;
381 
382 	while (node) {
383 		next = node->next;
384 		os_free(node);
385 		node = next;
386 	}
387 }
388 
os_dirent_ls(const char * dirname,struct os_dirent_node ** headp)389 int os_dirent_ls(const char *dirname, struct os_dirent_node **headp)
390 {
391 	struct dirent *entry;
392 	struct os_dirent_node *head, *node, *next;
393 	struct stat buf;
394 	DIR *dir;
395 	int ret;
396 	char *fname;
397 	char *old_fname;
398 	int len;
399 	int dirlen;
400 
401 	*headp = NULL;
402 	dir = opendir(dirname);
403 	if (!dir)
404 		return -1;
405 
406 	/* Create a buffer upfront, with typically sufficient size */
407 	dirlen = strlen(dirname) + 2;
408 	len = dirlen + 256;
409 	fname = os_malloc(len);
410 	if (!fname) {
411 		ret = -ENOMEM;
412 		goto done;
413 	}
414 
415 	for (node = head = NULL;; node = next) {
416 		errno = 0;
417 		entry = readdir(dir);
418 		if (!entry) {
419 			ret = errno;
420 			break;
421 		}
422 		next = os_malloc(sizeof(*node) + strlen(entry->d_name) + 1);
423 		if (!next) {
424 			os_dirent_free(head);
425 			ret = -ENOMEM;
426 			goto done;
427 		}
428 		if (dirlen + strlen(entry->d_name) > len) {
429 			len = dirlen + strlen(entry->d_name);
430 			old_fname = fname;
431 			fname = os_realloc(fname, len);
432 			if (!fname) {
433 				os_free(old_fname);
434 				os_free(next);
435 				os_dirent_free(head);
436 				ret = -ENOMEM;
437 				goto done;
438 			}
439 		}
440 		next->next = NULL;
441 		strcpy(next->name, entry->d_name);
442 		switch (entry->d_type) {
443 		case DT_REG:
444 			next->type = OS_FILET_REG;
445 			break;
446 		case DT_DIR:
447 			next->type = OS_FILET_DIR;
448 			break;
449 		case DT_LNK:
450 			next->type = OS_FILET_LNK;
451 			break;
452 		default:
453 			next->type = OS_FILET_UNKNOWN;
454 		}
455 		next->size = 0;
456 		snprintf(fname, len, "%s/%s", dirname, next->name);
457 		if (!stat(fname, &buf))
458 			next->size = buf.st_size;
459 		if (node)
460 			node->next = next;
461 		else
462 			head = next;
463 	}
464 	*headp = head;
465 
466 done:
467 	closedir(dir);
468 	os_free(fname);
469 	return ret;
470 }
471 
472 const char *os_dirent_typename[OS_FILET_COUNT] = {
473 	"   ",
474 	"SYM",
475 	"DIR",
476 	"???",
477 };
478 
os_dirent_get_typename(enum os_dirent_t type)479 const char *os_dirent_get_typename(enum os_dirent_t type)
480 {
481 	if (type >= OS_FILET_REG && type < OS_FILET_COUNT)
482 		return os_dirent_typename[type];
483 
484 	return os_dirent_typename[OS_FILET_UNKNOWN];
485 }
486 
os_get_filesize(const char * fname,loff_t * size)487 int os_get_filesize(const char *fname, loff_t *size)
488 {
489 	struct stat buf;
490 	int ret;
491 
492 	ret = stat(fname, &buf);
493 	if (ret)
494 		return ret;
495 	*size = buf.st_size;
496 	return 0;
497 }
498 
os_putc(int ch)499 void os_putc(int ch)
500 {
501 	putchar(ch);
502 }
503 
os_puts(const char * str)504 void os_puts(const char *str)
505 {
506 	while (*str)
507 		os_putc(*str++);
508 }
509 
os_write_ram_buf(const char * fname)510 int os_write_ram_buf(const char *fname)
511 {
512 	struct sandbox_state *state = state_get_current();
513 	int fd, ret;
514 
515 	fd = open(fname, O_CREAT | O_WRONLY, 0777);
516 	if (fd < 0)
517 		return -ENOENT;
518 	ret = write(fd, state->ram_buf, state->ram_size);
519 	close(fd);
520 	if (ret != state->ram_size)
521 		return -EIO;
522 
523 	return 0;
524 }
525 
os_read_ram_buf(const char * fname)526 int os_read_ram_buf(const char *fname)
527 {
528 	struct sandbox_state *state = state_get_current();
529 	int fd, ret;
530 	loff_t size;
531 
532 	ret = os_get_filesize(fname, &size);
533 	if (ret < 0)
534 		return ret;
535 	if (size != state->ram_size)
536 		return -ENOSPC;
537 	fd = open(fname, O_RDONLY);
538 	if (fd < 0)
539 		return -ENOENT;
540 
541 	ret = read(fd, state->ram_buf, state->ram_size);
542 	close(fd);
543 	if (ret != state->ram_size)
544 		return -EIO;
545 
546 	return 0;
547 }
548 
make_exec(char * fname,const void * data,int size)549 static int make_exec(char *fname, const void *data, int size)
550 {
551 	int fd;
552 
553 	strcpy(fname, "/tmp/u-boot.jump.XXXXXX");
554 	fd = mkstemp(fname);
555 	if (fd < 0)
556 		return -ENOENT;
557 	if (write(fd, data, size) < 0)
558 		return -EIO;
559 	close(fd);
560 	if (chmod(fname, 0777))
561 		return -ENOEXEC;
562 
563 	return 0;
564 }
565 
566 /**
567  * add_args() - Allocate a new argv with the given args
568  *
569  * This is used to create a new argv array with all the old arguments and some
570  * new ones that are passed in
571  *
572  * @argvp:  Returns newly allocated args list
573  * @add_args: Arguments to add, each a string
574  * @count: Number of arguments in @add_args
575  * @return 0 if OK, -ENOMEM if out of memory
576  */
add_args(char *** argvp,char * add_args[],int count)577 static int add_args(char ***argvp, char *add_args[], int count)
578 {
579 	char **argv, **ap;
580 	int argc;
581 
582 	for (argc = 0; (*argvp)[argc]; argc++)
583 		;
584 
585 	argv = os_malloc((argc + count + 1) * sizeof(char *));
586 	if (!argv) {
587 		printf("Out of memory for %d argv\n", count);
588 		return -ENOMEM;
589 	}
590 	for (ap = *argvp, argc = 0; *ap; ap++) {
591 		char *arg = *ap;
592 
593 		/* Drop args that we don't want to propagate */
594 		if (*arg == '-' && strlen(arg) == 2) {
595 			switch (arg[1]) {
596 			case 'j':
597 			case 'm':
598 				ap++;
599 				continue;
600 			}
601 		} else if (!strcmp(arg, "--rm_memory")) {
602 			ap++;
603 			continue;
604 		}
605 		argv[argc++] = arg;
606 	}
607 
608 	memcpy(argv + argc, add_args, count * sizeof(char *));
609 	argv[argc + count] = NULL;
610 
611 	*argvp = argv;
612 	return 0;
613 }
614 
615 /**
616  * os_jump_to_file() - Jump to a new program
617  *
618  * This saves the memory buffer, sets up arguments to the new process, then
619  * execs it.
620  *
621  * @fname: Filename to exec
622  * @return does not return on success, any return value is an error
623  */
os_jump_to_file(const char * fname)624 static int os_jump_to_file(const char *fname)
625 {
626 	struct sandbox_state *state = state_get_current();
627 	char mem_fname[30];
628 	int fd, err;
629 	char *extra_args[5];
630 	char **argv = state->argv;
631 	int argc;
632 #ifdef DEBUG
633 	int i;
634 #endif
635 
636 	strcpy(mem_fname, "/tmp/u-boot.mem.XXXXXX");
637 	fd = mkstemp(mem_fname);
638 	if (fd < 0)
639 		return -ENOENT;
640 	close(fd);
641 	err = os_write_ram_buf(mem_fname);
642 	if (err)
643 		return err;
644 
645 	os_fd_restore();
646 
647 	extra_args[0] = "-j";
648 	extra_args[1] = (char *)fname;
649 	extra_args[2] = "-m";
650 	extra_args[3] = mem_fname;
651 	argc = 4;
652 	if (state->ram_buf_rm)
653 		extra_args[argc++] = "--rm_memory";
654 	err = add_args(&argv, extra_args, argc);
655 	if (err)
656 		return err;
657 	argv[0] = (char *)fname;
658 
659 #ifdef DEBUG
660 	for (i = 0; argv[i]; i++)
661 		printf("%d %s\n", i, argv[i]);
662 #endif
663 
664 	if (state_uninit())
665 		os_exit(2);
666 
667 	err = execv(fname, argv);
668 	os_free(argv);
669 	if (err) {
670 		perror("Unable to run image");
671 		printf("Image filename '%s'\n", fname);
672 		return err;
673 	}
674 
675 	return unlink(fname);
676 }
677 
os_jump_to_image(const void * dest,int size)678 int os_jump_to_image(const void *dest, int size)
679 {
680 	char fname[30];
681 	int err;
682 
683 	err = make_exec(fname, dest, size);
684 	if (err)
685 		return err;
686 
687 	return os_jump_to_file(fname);
688 }
689 
os_find_u_boot(char * fname,int maxlen)690 int os_find_u_boot(char *fname, int maxlen)
691 {
692 	struct sandbox_state *state = state_get_current();
693 	const char *progname = state->argv[0];
694 	int len = strlen(progname);
695 	const char *suffix;
696 	char *p;
697 	int fd;
698 
699 	if (len >= maxlen || len < 4)
700 		return -ENOSPC;
701 
702 	strcpy(fname, progname);
703 	suffix = fname + len - 4;
704 
705 	/* If we are TPL, boot to SPL */
706 	if (!strcmp(suffix, "-tpl")) {
707 		fname[len - 3] = 's';
708 		fd = os_open(fname, O_RDONLY);
709 		if (fd >= 0) {
710 			close(fd);
711 			return 0;
712 		}
713 
714 		/* Look for 'u-boot-tpl' in the tpl/ directory */
715 		p = strstr(fname, "/tpl/");
716 		if (p) {
717 			p[1] = 's';
718 			fd = os_open(fname, O_RDONLY);
719 			if (fd >= 0) {
720 				close(fd);
721 				return 0;
722 			}
723 		}
724 		return -ENOENT;
725 	}
726 
727 	/* Look for 'u-boot' in the same directory as 'u-boot-spl' */
728 	if (!strcmp(suffix, "-spl")) {
729 		fname[len - 4] = '\0';
730 		fd = os_open(fname, O_RDONLY);
731 		if (fd >= 0) {
732 			close(fd);
733 			return 0;
734 		}
735 	}
736 
737 	/* Look for 'u-boot' in the parent directory of spl/ */
738 	p = strstr(fname, "spl/");
739 	if (p) {
740 		/* Remove the "spl" characters */
741 		memmove(p, p + 4, strlen(p + 4) + 1);
742 		fd = os_open(fname, O_RDONLY);
743 		if (fd >= 0) {
744 			close(fd);
745 			return 0;
746 		}
747 	}
748 
749 	return -ENOENT;
750 }
751 
os_spl_to_uboot(const char * fname)752 int os_spl_to_uboot(const char *fname)
753 {
754 	return os_jump_to_file(fname);
755 }
756 
os_localtime(struct rtc_time * rt)757 void os_localtime(struct rtc_time *rt)
758 {
759 	time_t t = time(NULL);
760 	struct tm *tm;
761 
762 	tm = localtime(&t);
763 	rt->tm_sec = tm->tm_sec;
764 	rt->tm_min = tm->tm_min;
765 	rt->tm_hour = tm->tm_hour;
766 	rt->tm_mday = tm->tm_mday;
767 	rt->tm_mon = tm->tm_mon + 1;
768 	rt->tm_year = tm->tm_year + 1900;
769 	rt->tm_wday = tm->tm_wday;
770 	rt->tm_yday = tm->tm_yday;
771 	rt->tm_isdst = tm->tm_isdst;
772 }
773 
os_abort(void)774 void os_abort(void)
775 {
776 	abort();
777 }
778 
os_mprotect_allow(void * start,size_t len)779 int os_mprotect_allow(void *start, size_t len)
780 {
781 	int page_size = getpagesize();
782 
783 	/* Move start to the start of a page, len to the end */
784 	start = (void *)(((ulong)start) & ~(page_size - 1));
785 	len = (len + page_size * 2) & ~(page_size - 1);
786 
787 	return mprotect(start, len, PROT_READ | PROT_WRITE);
788 }
789