123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450 |
- /*
- * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * 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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
- /**
- * @file
- *
- * Multiboot image format
- *
- */
-
- #include <stdio.h>
- #include <errno.h>
- #include <assert.h>
- #include <realmode.h>
- #include <multiboot.h>
- #include <gpxe/uaccess.h>
- #include <gpxe/image.h>
- #include <gpxe/segment.h>
- #include <gpxe/memmap.h>
- #include <gpxe/elf.h>
- #include <gpxe/init.h>
- #include <gpxe/features.h>
-
- FEATURE ( FEATURE_IMAGE, "Multiboot", DHCP_EB_FEATURE_MULTIBOOT, 1 );
-
- struct image_type multiboot_image_type __image_type ( PROBE_MULTIBOOT );
-
- /**
- * Maximum number of modules we will allow for
- *
- * If this has bitten you: sorry. I did have a perfect scheme with a
- * dynamically allocated list of modules on the protected-mode stack,
- * but it was incompatible with some broken OSes that can only access
- * low memory at boot time (even though we kindly set up 4GB flat
- * physical addressing as per the multiboot specification.
- *
- */
- #define MAX_MODULES 8
-
- /**
- * Maximum combined length of command lines
- *
- * Again; sorry. Some broken OSes zero out any non-base memory that
- * isn't part of the loaded module set, so we can't just use
- * virt_to_phys(cmdline) to point to the command lines, even though
- * this would comply with the Multiboot spec.
- */
- #define MB_MAX_CMDLINE 512
-
- /** Multiboot flags that we support */
- #define MB_SUPPORTED_FLAGS ( MB_FLAG_PGALIGN | MB_FLAG_MEMMAP | \
- MB_FLAG_VIDMODE | MB_FLAG_RAW )
-
- /** Compulsory feature multiboot flags */
- #define MB_COMPULSORY_FLAGS 0x0000ffff
-
- /** Optional feature multiboot flags */
- #define MB_OPTIONAL_FLAGS 0xffff0000
-
- /**
- * Multiboot flags that we don't support
- *
- * We only care about the compulsory feature flags (bits 0-15); we are
- * allowed to ignore the optional feature flags.
- */
- #define MB_UNSUPPORTED_FLAGS ( MB_COMPULSORY_FLAGS & ~MB_SUPPORTED_FLAGS )
-
- /** A multiboot header descriptor */
- struct multiboot_header_info {
- /** The actual multiboot header */
- struct multiboot_header mb;
- /** Offset of header within the multiboot image */
- size_t offset;
- };
-
- /** Multiboot module command lines */
- static char __bss16_array ( mb_cmdlines, [MB_MAX_CMDLINE] );
- #define mb_cmdlines __use_data16 ( mb_cmdlines )
-
- /** Offset within module command lines */
- static unsigned int mb_cmdline_offset;
-
- /**
- * Build multiboot memory map
- *
- * @v image Multiboot image
- * @v mbinfo Multiboot information structure
- * @v mbmemmap Multiboot memory map
- * @v limit Maxmimum number of memory map entries
- */
- static void multiboot_build_memmap ( struct image *image,
- struct multiboot_info *mbinfo,
- struct multiboot_memory_map *mbmemmap,
- unsigned int limit ) {
- struct memory_map memmap;
- unsigned int i;
-
- /* Get memory map */
- get_memmap ( &memmap );
-
- /* Translate into multiboot format */
- memset ( mbmemmap, 0, sizeof ( *mbmemmap ) );
- for ( i = 0 ; i < memmap.count ; i++ ) {
- if ( i >= limit ) {
- DBGC ( image, "MULTIBOOT %p limit of %d memmap "
- "entries reached\n", image, limit );
- break;
- }
- mbmemmap[i].size = ( sizeof ( mbmemmap[i] ) -
- sizeof ( mbmemmap[i].size ) );
- mbmemmap[i].base_addr = memmap.regions[i].start;
- mbmemmap[i].length = ( memmap.regions[i].end -
- memmap.regions[i].start );
- mbmemmap[i].type = MBMEM_RAM;
- mbinfo->mmap_length += sizeof ( mbmemmap[i] );
- if ( memmap.regions[i].start == 0 )
- mbinfo->mem_lower = ( memmap.regions[i].end / 1024 );
- if ( memmap.regions[i].start == 0x100000 )
- mbinfo->mem_upper = ( ( memmap.regions[i].end -
- 0x100000 ) / 1024 );
- }
- }
-
- /**
- * Add command line in base memory
- *
- * @v cmdline Command line
- * @ret physaddr Physical address of command line
- */
- physaddr_t multiboot_add_cmdline ( const char *cmdline ) {
- char *mb_cmdline;
-
- if ( ! cmdline )
- cmdline = "";
-
- /* Copy command line to base memory buffer */
- mb_cmdline = ( mb_cmdlines + mb_cmdline_offset );
- mb_cmdline_offset +=
- ( snprintf ( mb_cmdline,
- ( sizeof ( mb_cmdlines ) - mb_cmdline_offset ),
- "%s", cmdline ) + 1 );
-
- /* Truncate to terminating NUL in buffer if necessary */
- if ( mb_cmdline_offset > sizeof ( mb_cmdlines ) )
- mb_cmdline_offset = ( sizeof ( mb_cmdlines ) - 1 );
-
- return virt_to_phys ( mb_cmdline );
- }
-
- /**
- * Build multiboot module list
- *
- * @v image Multiboot image
- * @v modules Module list to fill, or NULL
- * @ret count Number of modules
- */
- static unsigned int
- multiboot_build_module_list ( struct image *image,
- struct multiboot_module *modules,
- unsigned int limit ) {
- struct image *module_image;
- struct multiboot_module *module;
- unsigned int count = 0;
- unsigned int insert;
- physaddr_t start;
- physaddr_t end;
- unsigned int i;
-
- /* Add each image as a multiboot module */
- for_each_image ( module_image ) {
-
- if ( count >= limit ) {
- DBGC ( image, "MULTIBOOT %p limit of %d modules "
- "reached\n", image, limit );
- break;
- }
-
- /* Do not include kernel image itself as a module */
- if ( module_image == image )
- continue;
-
- /* At least some OSes expect the multiboot modules to
- * be in ascending order, so we have to support it.
- */
- start = user_to_phys ( module_image->data, 0 );
- end = user_to_phys ( module_image->data, module_image->len );
- for ( insert = 0 ; insert < count ; insert++ ) {
- if ( start < modules[insert].mod_start )
- break;
- }
- module = &modules[insert];
- memmove ( ( module + 1 ), module,
- ( ( count - insert ) * sizeof ( *module ) ) );
- module->mod_start = start;
- module->mod_end = end;
- module->string =
- multiboot_add_cmdline ( module_image->cmdline );
- module->reserved = 0;
-
- /* We promise to page-align modules */
- assert ( ( module->mod_start & 0xfff ) == 0 );
-
- count++;
- }
-
- /* Dump module configuration */
- for ( i = 0 ; i < count ; i++ ) {
- DBGC ( image, "MULTIBOOT %p module %d is [%lx,%lx)\n",
- image, i, modules[i].mod_start,
- modules[i].mod_end );
- }
-
- return count;
- }
-
- /**
- * The multiboot information structure
- *
- * Kept in base memory because some OSes won't find it elsewhere,
- * along with the other structures belonging to the Multiboot
- * information table.
- */
- static struct multiboot_info __bss16 ( mbinfo );
- #define mbinfo __use_data16 ( mbinfo )
-
- /** The multiboot bootloader name */
- static char __data16_array ( mb_bootloader_name, [] ) = "gPXE " VERSION;
- #define mb_bootloader_name __use_data16 ( mb_bootloader_name )
-
- /** The multiboot memory map */
- static struct multiboot_memory_map
- __bss16_array ( mbmemmap, [MAX_MEMORY_REGIONS] );
- #define mbmemmap __use_data16 ( mbmemmap )
-
- /** The multiboot module list */
- static struct multiboot_module __bss16_array ( mbmodules, [MAX_MODULES] );
- #define mbmodules __use_data16 ( mbmodules )
-
- /**
- * Execute multiboot image
- *
- * @v image Multiboot image
- * @ret rc Return status code
- */
- static int multiboot_exec ( struct image *image ) {
- physaddr_t entry = image->priv.phys;
-
- /* Populate multiboot information structure */
- memset ( &mbinfo, 0, sizeof ( mbinfo ) );
- mbinfo.flags = ( MBI_FLAG_LOADER | MBI_FLAG_MEM | MBI_FLAG_MMAP |
- MBI_FLAG_CMDLINE | MBI_FLAG_MODS );
- multiboot_build_memmap ( image, &mbinfo, mbmemmap,
- ( sizeof(mbmemmap) / sizeof(mbmemmap[0]) ) );
- mb_cmdline_offset = 0;
- mbinfo.cmdline = multiboot_add_cmdline ( image->cmdline );
- mbinfo.mods_count = multiboot_build_module_list ( image, mbmodules,
- ( sizeof(mbmodules) / sizeof(mbmodules[0]) ) );
- mbinfo.mods_addr = virt_to_phys ( mbmodules );
- mbinfo.mmap_addr = virt_to_phys ( mbmemmap );
- mbinfo.boot_loader_name = virt_to_phys ( mb_bootloader_name );
-
- /* Multiboot images may not return and have no callback
- * interface, so shut everything down prior to booting the OS.
- */
- shutdown ( SHUTDOWN_BOOT );
-
- /* Jump to OS with flat physical addressing */
- DBGC ( image, "MULTIBOOT %p starting execution at %lx\n",
- image, entry );
- __asm__ __volatile__ ( PHYS_CODE ( "call *%%edi\n\t" )
- : : "a" ( MULTIBOOT_BOOTLOADER_MAGIC ),
- "b" ( virt_to_phys ( &mbinfo ) ),
- "D" ( entry )
- : "ecx", "edx", "esi", "ebp", "memory" );
-
- DBGC ( image, "MULTIBOOT %p returned\n", image );
-
- /* It isn't safe to continue after calling shutdown() */
- while ( 1 ) {}
-
- return -ECANCELED; /* -EIMPOSSIBLE, anyone? */
- }
-
- /**
- * Find multiboot header
- *
- * @v image Multiboot file
- * @v hdr Multiboot header descriptor to fill in
- * @ret rc Return status code
- */
- static int multiboot_find_header ( struct image *image,
- struct multiboot_header_info *hdr ) {
- uint32_t buf[64];
- size_t offset;
- unsigned int buf_idx;
- uint32_t checksum;
-
- /* Scan through first 8kB of image file 256 bytes at a time.
- * (Use the buffering to avoid the overhead of a
- * copy_from_user() for every dword.)
- */
- for ( offset = 0 ; offset < 8192 ; offset += sizeof ( buf[0] ) ) {
- /* Check for end of image */
- if ( offset > image->len )
- break;
- /* Refill buffer if applicable */
- buf_idx = ( ( offset % sizeof ( buf ) ) / sizeof ( buf[0] ) );
- if ( buf_idx == 0 ) {
- copy_from_user ( buf, image->data, offset,
- sizeof ( buf ) );
- }
- /* Check signature */
- if ( buf[buf_idx] != MULTIBOOT_HEADER_MAGIC )
- continue;
- /* Copy header and verify checksum */
- copy_from_user ( &hdr->mb, image->data, offset,
- sizeof ( hdr->mb ) );
- checksum = ( hdr->mb.magic + hdr->mb.flags +
- hdr->mb.checksum );
- if ( checksum != 0 )
- continue;
- /* Record offset of multiboot header and return */
- hdr->offset = offset;
- return 0;
- }
-
- /* No multiboot header found */
- return -ENOEXEC;
- }
-
- /**
- * Load raw multiboot image into memory
- *
- * @v image Multiboot file
- * @v hdr Multiboot header descriptor
- * @ret rc Return status code
- */
- static int multiboot_load_raw ( struct image *image,
- struct multiboot_header_info *hdr ) {
- size_t offset;
- size_t filesz;
- size_t memsz;
- userptr_t buffer;
- int rc;
-
- /* Verify and prepare segment */
- offset = ( hdr->offset - hdr->mb.header_addr + hdr->mb.load_addr );
- filesz = ( hdr->mb.load_end_addr ?
- ( hdr->mb.load_end_addr - hdr->mb.load_addr ) :
- ( image->len - offset ) );
- memsz = ( hdr->mb.bss_end_addr ?
- ( hdr->mb.bss_end_addr - hdr->mb.load_addr ) : filesz );
- buffer = phys_to_user ( hdr->mb.load_addr );
- if ( ( rc = prep_segment ( buffer, filesz, memsz ) ) != 0 ) {
- DBGC ( image, "MULTIBOOT %p could not prepare segment: %s\n",
- image, strerror ( rc ) );
- return rc;
- }
-
- /* Copy image to segment */
- memcpy_user ( buffer, 0, image->data, offset, filesz );
-
- /* Record execution entry point in image private data field */
- image->priv.phys = hdr->mb.entry_addr;
-
- return 0;
- }
-
- /**
- * Load ELF multiboot image into memory
- *
- * @v image Multiboot file
- * @ret rc Return status code
- */
- static int multiboot_load_elf ( struct image *image ) {
- int rc;
-
- /* Load ELF image*/
- if ( ( rc = elf_load ( image ) ) != 0 ) {
- DBGC ( image, "MULTIBOOT %p ELF image failed to load: %s\n",
- image, strerror ( rc ) );
- return rc;
- }
-
- return 0;
- }
-
- /**
- * Load multiboot image into memory
- *
- * @v image Multiboot file
- * @ret rc Return status code
- */
- static int multiboot_load ( struct image *image ) {
- struct multiboot_header_info hdr;
- int rc;
-
- /* Locate multiboot header, if present */
- if ( ( rc = multiboot_find_header ( image, &hdr ) ) != 0 ) {
- DBGC ( image, "MULTIBOOT %p has no multiboot header\n",
- image );
- return rc;
- }
- DBGC ( image, "MULTIBOOT %p found header with flags %08lx\n",
- image, hdr.mb.flags );
-
- /* This is a multiboot image, valid or otherwise */
- if ( ! image->type )
- image->type = &multiboot_image_type;
-
- /* Abort if we detect flags that we cannot support */
- if ( hdr.mb.flags & MB_UNSUPPORTED_FLAGS ) {
- DBGC ( image, "MULTIBOOT %p flags %08lx not supported\n",
- image, ( hdr.mb.flags & MB_UNSUPPORTED_FLAGS ) );
- return -ENOTSUP;
- }
-
- /* Load the actual image */
- if ( hdr.mb.flags & MB_FLAG_RAW ) {
- if ( ( rc = multiboot_load_raw ( image, &hdr ) ) != 0 )
- return rc;
- } else {
- if ( ( rc = multiboot_load_elf ( image ) ) != 0 )
- return rc;
- }
-
- return 0;
- }
-
- /** Multiboot image type */
- struct image_type multiboot_image_type __image_type ( PROBE_MULTIBOOT ) = {
- .name = "Multiboot",
- .load = multiboot_load,
- .exec = multiboot_exec,
- };
|