cregit-Linux how code gets into the kernel

Release 4.14 drivers/mtd/redboot.c

Directory: drivers/mtd
/*
 * Parse RedBoot-style Flash Image System (FIS) tables and
 * produce a Linux partition array to match.
 *
 * Copyright © 2001      Red Hat UK Limited
 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/vmalloc.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/module.h>


struct fis_image_desc {
    
unsigned char name[16];      // Null terminated name
    
uint32_t	  flash_base;    // Address within FLASH of image
    
uint32_t	  mem_base;      // Address in memory where it executes
    
uint32_t	  size;          // Length of image
    
uint32_t	  entry_point;   // Execution entry point
    
uint32_t	  data_length;   // Length of actual data
    
unsigned char _pad[256-(16+7*sizeof(uint32_t))];
    
uint32_t	  desc_cksum;    // Checksum over image descriptor
    
uint32_t	  file_cksum;    // Checksum over image data
};


struct fis_list {
	
struct fis_image_desc *img;
	
struct fis_list *next;
};


static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
module_param(directory, int, 0);


static inline int redboot_checksum(struct fis_image_desc *img) { /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */ return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds16100.00%1100.00%
Total16100.00%1100.00%


static int parse_redboot_partitions(struct mtd_info *master, const struct mtd_partition **pparts, struct mtd_part_parser_data *data) { int nrparts = 0; struct fis_image_desc *buf; struct mtd_partition *parts; struct fis_list *fl = NULL, *tmp_fl; int ret, i; size_t retlen; char *names; char *nullname; int namelen = 0; int nulllen = 0; int numslots; unsigned long offset; #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED static char nullstring[] = "unallocated"; #endif if ( directory < 0 ) { offset = master->size + directory * master->erasesize; while (mtd_block_isbad(master, offset)) { if (!offset) { nogood: printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n"); return -EIO; } offset -= master->erasesize; } } else { offset = directory * master->erasesize; while (mtd_block_isbad(master, offset)) { offset += master->erasesize; if (offset == master->size) goto nogood; } } buf = vmalloc(master->erasesize); if (!buf) return -ENOMEM; printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n", master->name, offset); ret = mtd_read(master, offset, master->erasesize, &retlen, (void *)buf); if (ret) goto out; if (retlen != master->erasesize) { ret = -EIO; goto out; } numslots = (master->erasesize / sizeof(struct fis_image_desc)); for (i = 0; i < numslots; i++) { if (!memcmp(buf[i].name, "FIS directory", 14)) { /* This is apparently the FIS directory entry for the * FIS directory itself. The FIS directory size is * one erase block; if the buf[i].size field is * swab32(erasesize) then we know we are looking at * a byte swapped FIS directory - swap all the entries! * (NOTE: this is 'size' not 'data_length'; size is * the full size of the entry.) */ /* RedBoot can combine the FIS directory and config partitions into a single eraseblock; we assume wrong-endian if either the swapped 'size' matches the eraseblock size precisely, or if the swapped size actually fits in an eraseblock while the unswapped size doesn't. */ if (swab32(buf[i].size) == master->erasesize || (buf[i].size > master->erasesize && swab32(buf[i].size) < master->erasesize)) { int j; /* Update numslots based on actual FIS directory size */ numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc); for (j = 0; j < numslots; ++j) { /* A single 0xff denotes a deleted entry. * Two of them in a row is the end of the table. */ if (buf[j].name[0] == 0xff) { if (buf[j].name[1] == 0xff) { break; } else { continue; } } /* The unsigned long fields were written with the * wrong byte sex, name and pad have no byte sex. */ swab32s(&buf[j].flash_base); swab32s(&buf[j].mem_base); swab32s(&buf[j].size); swab32s(&buf[j].entry_point); swab32s(&buf[j].data_length); swab32s(&buf[j].desc_cksum); swab32s(&buf[j].file_cksum); } } else if (buf[i].size < master->erasesize) { /* Update numslots based on actual FIS directory size */ numslots = buf[i].size / sizeof(struct fis_image_desc); } break; } } if (i == numslots) { /* Didn't find it */ printk(KERN_NOTICE "No RedBoot partition table detected in %s\n", master->name); ret = 0; goto out; } for (i = 0; i < numslots; i++) { struct fis_list *new_fl, **prev; if (buf[i].name[0] == 0xff) { if (buf[i].name[1] == 0xff) { break; } else { continue; } } if (!redboot_checksum(&buf[i])) break; new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL); namelen += strlen(buf[i].name)+1; if (!new_fl) { ret = -ENOMEM; goto out; } new_fl->img = &buf[i]; if (data && data->origin) buf[i].flash_base -= data->origin; else buf[i].flash_base &= master->size-1; /* I'm sure the JFFS2 code has done me permanent damage. * I now think the following is _normal_ */ prev = &fl; while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base) prev = &(*prev)->next; new_fl->next = *prev; *prev = new_fl; nrparts++; } #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED if (fl->img->flash_base) { nrparts++; nulllen = sizeof(nullstring); } for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) { if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) { nrparts++; nulllen = sizeof(nullstring); } } #endif parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL); if (!parts) { ret = -ENOMEM; goto out; } nullname = (char *)&parts[nrparts]; #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED if (nulllen > 0) { strcpy(nullname, nullstring); } #endif names = nullname + nulllen; i=0; #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED if (fl->img->flash_base) { parts[0].name = nullname; parts[0].size = fl->img->flash_base; parts[0].offset = 0; i++; } #endif for ( ; i<nrparts; i++) { parts[i].size = fl->img->size; parts[i].offset = fl->img->flash_base; parts[i].name = names; strcpy(names, fl->img->name); #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY if (!memcmp(names, "RedBoot", 8) || !memcmp(names, "RedBoot config", 15) || !memcmp(names, "FIS directory", 14)) { parts[i].mask_flags = MTD_WRITEABLE; } #endif names += strlen(names)+1; #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) { i++; parts[i].offset = parts[i-1].size + parts[i-1].offset; parts[i].size = fl->next->img->flash_base - parts[i].offset; parts[i].name = nullname; } #endif tmp_fl = fl; fl = fl->next; kfree(tmp_fl); } ret = nrparts; *pparts = parts; out: while (fl) { struct fis_list *old = fl; fl = fl->next; kfree(old); } vfree(buf); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds66352.74%210.53%
David Woodhouse36028.64%631.58%
John Bowler1249.86%210.53%
Rod Whitby755.97%210.53%
Yoshinori Sato171.35%15.26%
Dmitry Baryshkov120.95%15.26%
Artem B. Bityutskiy30.24%210.53%
Peter Korsgaard10.08%15.26%
Brian Norris10.08%15.26%
Burman Yan10.08%15.26%
Total1257100.00%19100.00%

static struct mtd_part_parser redboot_parser = { .parse_fn = parse_redboot_partitions, .name = "RedBoot", }; module_mtd_part_parser(redboot_parser); /* mtd parsers will request the module by parser name */ MODULE_ALIAS("RedBoot"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");

Overall Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds76653.68%312.00%
David Woodhouse40528.38%832.00%
John Bowler1248.69%28.00%
Rod Whitby755.26%28.00%
Yoshinori Sato171.19%14.00%
Ben Dooks151.05%14.00%
Dmitry Baryshkov120.84%14.00%
Brian Norris50.35%28.00%
Paul Gortmaker30.21%14.00%
Artem B. Bityutskiy30.21%28.00%
Burman Yan10.07%14.00%
Peter Korsgaard10.07%14.00%
Total1427100.00%25100.00%
Directory: drivers/mtd
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