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Ensure multiboot modules are in ascending order of memory start 

address, to work around OS bugs.
This commit is contained in:
Michael Brown 2007-01-12 12:03:19 +00:00
parent 53e948bba8
commit 0f29e0e46e
1 changed files with 39 additions and 14 deletions
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53
src/arch/i386/image/multiboot.c
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@ -106,28 +106,53 @@ multiboot_build_module_list ( struct image *image,
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 ) {
/* Do not include kernel image itself as a module */
if ( module_image == image )
continue;
module = &modules[count++];
/* Populate module data structure, if applicable */
if ( ! modules )
continue;
module->mod_start = user_to_phys ( module_image->data, 0 );
module->mod_end = user_to_phys ( module_image->data,
module_image->len );
module->string = virt_to_phys ( module_image->cmdline );
module->reserved = 0;
DBG ( "Multiboot module %lx is [%lx,%lx)\n",
virt_to_phys ( module ),
module->mod_start, module->mod_end );
/* If we don't have a data structure to populate, just count */
if ( modules ) {
/* 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 = virt_to_phys ( module_image->cmdline);
module->reserved = 0;
/* We promise to page-align modules */
assert ( ( module->mod_start & 0xfff ) == 0 );
}
/* We promise to page-align modules, so at least check */
assert ( ( module->mod_start & 0xfff ) == 0 );
count++;
}
/* Dump module configuration */
if ( modules ) {
for ( i = 0 ; i < count ; i++ ) {
DBG ( "Multiboot module %d is [%lx,%lx)\n", i,
modules[i].mod_start, modules[i].mod_end );
}
}
return count;