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/*
* 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
*
* Linux bzImage image format
*
*/
#include <errno.h>
#include <assert.h>
#include <realmode.h>
#include <bzimage.h>
#include <gpxe/uaccess.h>
#include <gpxe/image.h>
#include <gpxe/segment.h>
#include <gpxe/memmap.h>
#include <gpxe/shutdown.h>
struct image_type bzimage_image_type __image_type ( PROBE_NORMAL );
/**
* bzImage execution context
*/
union bzimage_exec_context {
/** Real-mode parameters */
struct {
/** Kernel real-mode data segment */
uint16_t kernel_seg;
/** Kernel real-mode stack pointer */
uint16_t stack;
} rm;
unsigned long ul;
};
/**
* Execute bzImage image
*
* @v image bzImage image
* @ret rc Return status code
*/
static int bzimage_exec ( struct image *image ) {
union bzimage_exec_context context;
/* Retrieve stored execution context */
context.ul = image->priv.ul;
/* Prepare for exiting */
shutdown();
/* Jump to the kernel */
__asm__ __volatile__ ( REAL_CODE ( "movw %w0, %%ds\n\t"
"movw %w0, %%es\n\t"
"movw %w0, %%fs\n\t"
"movw %w0, %%gs\n\t"
"movw %w0, %%ss\n\t"
"movw %w1, %%sp\n\t"
"pushw %w2\n\t"
"pushw $0\n\t"
"lret\n\t" )
: : "r" ( context.rm.kernel_seg ),
"r" ( context.rm.stack ),
"r" ( context.rm.kernel_seg + 0x20 ) );
/* There is no way for the image to return, since we provide
* no return address.
*/
assert ( 0 );
return -ECANCELED; /* -EIMPOSSIBLE */
}
/**
* Load bzImage image into memory
*
* @v image bzImage file
* @ret rc Return status code
*/
int bzimage_load ( struct image *image ) {
struct bzimage_header bzhdr;
union bzimage_exec_context context;
unsigned int rm_kernel_seg = 0x1000; /* place RM kernel at 1000:0000 */
userptr_t rm_kernel = real_to_user ( rm_kernel_seg, 0 );
userptr_t pm_kernel;
size_t rm_filesz;
size_t rm_memsz;
size_t pm_filesz;
size_t pm_memsz;
size_t rm_heap_end;
size_t rm_cmdline;
int rc;
/* Sanity check */
if ( image->len < ( BZI_HDR_OFFSET + sizeof ( bzhdr ) ) ) {
DBGC ( image, "bzImage %p too short for kernel header\n",
image );
return -ENOEXEC;
}
/* Read and verify header */
copy_from_user ( &bzhdr, image->data, BZI_HDR_OFFSET,
sizeof ( bzhdr ) );
if ( bzhdr.header != BZI_SIGNATURE ) {
DBGC ( image, "bzImage %p not a bzImage\n", image );
return -ENOEXEC;
}
/* This is a bzImage image, valid or otherwise */
if ( ! image->type )
image->type = &bzimage_image_type;
/* We don't support ancient kernels */
if ( bzhdr.version < 0x0200 ) {
DBGC ( image, "bzImage %p version %04x not supported\n",
image, bzhdr.version );
return -ENOTSUP;
}
DBGC ( image, "bzImage %p version %04x\n", image, bzhdr.version );
/* Check size of base memory portions */
rm_filesz = ( ( bzhdr.setup_sects ? bzhdr.setup_sects : 4 ) + 1 ) << 9;
if ( rm_filesz > image->len ) {
DBGC ( image, "bzImage %p too short for %zd byte of setup\n",
image, rm_filesz );
return -ENOEXEC;
}
rm_memsz = rm_filesz;
/* Allow space for the stack and heap */
rm_memsz += BZI_STACK_SIZE;
rm_heap_end = rm_memsz;
/* Allow space for the command line, if one exists */
rm_cmdline = rm_memsz;
if ( image->cmdline )
rm_memsz += ( strlen ( image->cmdline ) + 1 );
/* Prepare, verify, and load the real-mode segment */
if ( ( rc = prep_segment ( rm_kernel, rm_filesz, rm_memsz ) ) != 0 ) {
DBGC ( image, "bzImage %p could not prepare RM segment: %s\n",
image, strerror ( rc ) );
return rc;
}
memcpy_user ( rm_kernel, 0, image->data, 0, rm_filesz );
/* Prepare, verify and load the rest of the kernel */
pm_kernel = ( ( bzhdr.loadflags & BZI_LOAD_HIGH ) ?
phys_to_user ( 0x100000 ) : phys_to_user ( 0x10000 ) );
pm_filesz = pm_memsz = ( image->len - rm_filesz );
if ( ( rc = prep_segment ( pm_kernel, pm_filesz, pm_memsz ) ) != 0 ) {
DBGC ( image, "bzImage %p could not prepare PM segment: %s\n",
image, strerror ( rc ) );
return rc;
}
memcpy_user ( pm_kernel, 0, image->data, rm_filesz, pm_filesz );
/* Copy down the command line, if it exists */
if ( image->cmdline ) {
copy_to_user ( rm_kernel, rm_cmdline, image->cmdline,
strlen ( image->cmdline ) + 1 );
}
/* Update the header and copy it into the loaded kernel */
bzhdr.type_of_loader = BZI_LOADER_TYPE_ETHERBOOT;
if ( bzhdr.version >= 0x0201 ) {
bzhdr.heap_end_ptr = ( rm_heap_end - 0x200 );
bzhdr.loadflags |= BZI_CAN_USE_HEAP;
}
if ( bzhdr.version >= 0x0202 ) {
bzhdr.cmd_line_ptr = user_to_phys ( rm_kernel, rm_cmdline );
} else {
uint16_t cmd_line_magic = BZI_CMD_LINE_MAGIC;
uint16_t cmd_line_offset = rm_cmdline;
put_real ( cmd_line_magic, rm_kernel_seg,
BZI_CMD_LINE_MAGIC_OFFSET );
put_real ( cmd_line_offset, rm_kernel_seg,
BZI_CMD_LINE_OFFSET_OFFSET );
bzhdr.setup_move_size = rm_memsz;
}
copy_to_user ( rm_kernel, BZI_HDR_OFFSET, &bzhdr, sizeof ( bzhdr ) );
/* Record execution context in image private data field */
context.rm.kernel_seg = rm_kernel_seg;
context.rm.stack = rm_heap_end;
image->priv.ul = context.ul;
return 0;
}
/** Linux bzImage image type */
struct image_type bzimage_image_type __image_type ( PROBE_NORMAL ) = {
.name = "bzImage",
.load = bzimage_load,
.exec = bzimage_exec,
};
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