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Split bzimage_load into separate functions

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This commit is contained in:
Michael Brown 2007-01-14 13:36:33 +00:00
parent 97a3037f76
commit 3ccd7335f0
2 changed files with 228 additions and 113 deletions
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316
src/arch/i386/image/bzimage.c
View File

@ -35,18 +35,36 @@
struct image_type bzimage_image_type __image_type ( PROBE_NORMAL );
/**
* bzImage load context
*/
struct bzimage_load_context {
/** Real-mode kernel portion load segment address */
unsigned int rm_kernel_seg;
/** Real-mode kernel portion load address */
userptr_t rm_kernel;
/** Real-mode kernel portion file size */
size_t rm_filesz;
/** Real-mode heap top (offset from rm_kernel) */
size_t rm_heap;
/** Command line (offset from rm_kernel) */
size_t rm_cmdline;
/** Real-mode kernel portion total memory size */
size_t rm_memsz;
/** Non-real-mode kernel portion load address */
userptr_t pm_kernel;
/** Non-real-mode kernel portion file and memory size */
size_t pm_sz;
};
/**
* 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;
struct bzimage_exec_context {
/** Kernel real-mode data segment */
uint16_t kernel_seg;
/** Kernel real-mode stack pointer */
uint16_t stack;
};
/**
@ -56,10 +74,13 @@ union bzimage_exec_context {
* @ret rc Return status code
*/
static int bzimage_exec ( struct image *image ) {
union bzimage_exec_context context;
union {
struct bzimage_exec_context bz;
unsigned long ul;
} exec_ctx;
/* Retrieve stored execution context */
context.ul = image->priv.ul;
exec_ctx.ul = image->priv.ul;
/* Prepare for exiting */
shutdown();
@ -74,9 +95,9 @@ static int bzimage_exec ( struct image *image ) {
"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 ) );
: : "r" ( exec_ctx.bz.kernel_seg ),
"r" ( exec_ctx.bz.stack ),
"r" ( exec_ctx.bz.kernel_seg + 0x20 ) );
/* There is no way for the image to return, since we provide
* no return address.
@ -86,6 +107,161 @@ static int bzimage_exec ( struct image *image ) {
return -ECANCELED; /* -EIMPOSSIBLE */
}
/**
* Load and parse bzImage header
*
* @v image bzImage file
* @v load_ctx Load context
* @v bzhdr Buffer for bzImage header
* @ret rc Return status code
*/
static int bzimage_load_header ( struct image *image,
struct bzimage_load_context *load_ctx,
struct bzimage_header *bzhdr ) {
/* 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 bad signature\n", image );
return -ENOEXEC;
}
/* We don't support ancient kernels */
if ( bzhdr->version < 0x0200 ) {
DBGC ( image, "bzImage %p version %04x not supported\n",
image, bzhdr->version );
return -ENOTSUP;
}
/* Calculate load address and size of real-mode portion */
load_ctx->rm_kernel_seg = 0x1000; /* place RM kernel at 1000:0000 */
load_ctx->rm_kernel = real_to_user ( load_ctx->rm_kernel_seg, 0 );
load_ctx->rm_filesz = load_ctx->rm_memsz =
( ( bzhdr->setup_sects ? bzhdr->setup_sects : 4 ) + 1 ) << 9;
if ( load_ctx->rm_filesz > image->len ) {
DBGC ( image, "bzImage %p too short for %zd byte of setup\n",
image, load_ctx->rm_filesz );
return -ENOEXEC;
}
/* Calculate load address and size of non-real-mode portion */
load_ctx->pm_kernel = ( ( bzhdr->loadflags & BZI_LOAD_HIGH ) ?
phys_to_user ( BZI_LOAD_HIGH_ADDR ) :
phys_to_user ( BZI_LOAD_LOW_ADDR ) );
load_ctx->pm_sz = ( image->len - load_ctx->rm_filesz );
DBGC ( image, "bzImage %p version %04x RM %#zx bytes PM %#zx bytes\n",
image, bzhdr->version, load_ctx->rm_filesz, load_ctx->pm_sz );
return 0;
}
/**
* Load real-mode portion of bzImage
*
* @v image bzImage file
* @v load_ctx Load context
* @v cmdline Kernel command line
* @ret rc Return status code
*/
static int bzimage_load_real ( struct image *image,
struct bzimage_load_context *load_ctx,
const char *cmdline ) {
size_t cmdline_len = ( strlen ( cmdline ) + 1 );
int rc;
/* Allow space for the stack and heap */
load_ctx->rm_memsz += BZI_STACK_SIZE;
load_ctx->rm_heap = load_ctx->rm_memsz;
/* Allow space for the command line, if one exists */
load_ctx->rm_cmdline = load_ctx->rm_memsz;
load_ctx->rm_memsz += cmdline_len;
/* Prepare, verify, and load the real-mode segment */
if ( ( rc = prep_segment ( load_ctx->rm_kernel, load_ctx->rm_filesz,
load_ctx->rm_memsz ) ) != 0 ) {
DBGC ( image, "bzImage %p could not prepare RM segment: %s\n",
image, strerror ( rc ) );
return rc;
}
memcpy_user ( load_ctx->rm_kernel, 0, image->data, 0,
load_ctx->rm_filesz );
/* Copy command line */
copy_to_user ( load_ctx->rm_kernel, load_ctx->rm_cmdline,
cmdline, cmdline_len );
return 0;
}
/**
* Load non-real-mode portion of bzImage
*
* @v image bzImage file
* @v load_ctx Load context
* @ret rc Return status code
*/
static int bzimage_load_non_real ( struct image *image,
struct bzimage_load_context *load_ctx ) {
int rc;
/* Prepare, verify and load the non-real-mode segment */
if ( ( rc = prep_segment ( load_ctx->pm_kernel, load_ctx->pm_sz,
load_ctx->pm_sz ) ) != 0 ) {
DBGC ( image, "bzImage %p could not prepare PM segment: %s\n",
image, strerror ( rc ) );
return rc;
}
memcpy_user ( load_ctx->pm_kernel, 0, image->data, load_ctx->rm_filesz,
load_ctx->pm_sz );
return 0;
}
/**
* Update and store bzImage header
*
* @v image bzImage file
* @v load_ctx Load context
* @v bzhdr Original bzImage header
* @ret rc Return status code
*/
static int bzimage_write_header ( struct image *image __unused,
struct bzimage_load_context *load_ctx,
struct bzimage_header *bzhdr ) {
struct bzimage_cmdline cmdline;
/* 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 = ( load_ctx->rm_heap - 0x200 );
bzhdr->loadflags |= BZI_CAN_USE_HEAP;
}
if ( bzhdr->version >= 0x0202 ) {
bzhdr->cmd_line_ptr = user_to_phys ( load_ctx->rm_kernel,
load_ctx->rm_cmdline );
} else {
cmdline.magic = BZI_CMDLINE_MAGIC;
cmdline.offset = load_ctx->rm_cmdline;
copy_to_user ( load_ctx->rm_kernel, BZI_CMDLINE_OFFSET,
&cmdline, sizeof ( cmdline ) );
bzhdr->setup_move_size = load_ctx->rm_memsz;
}
copy_to_user ( load_ctx->rm_kernel, BZI_HDR_OFFSET,
bzhdr, sizeof ( *bzhdr ) );
return 0;
}
/**
* Load bzImage image into memory
*
@ -94,112 +270,38 @@ static int bzimage_exec ( struct image *image ) {
*/
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;
struct bzimage_load_context load_ctx;
union {
struct bzimage_exec_context bz;
unsigned long ul;
} exec_ctx;
const char *cmdline = ( image->cmdline ? image->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;
}
/* Load and verify header */
if ( ( rc = bzimage_load_header ( image, &load_ctx, &bzhdr ) ) != 0 )
return rc;
/* 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 ) );
/* Load real-mode portion */
if ( ( rc = bzimage_load_real ( image, &load_ctx, cmdline ) ) != 0 )
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 ) );
/* Load non-real-mode portion */
if ( ( rc = bzimage_load_non_real ( image, &load_ctx ) ) != 0 )
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 ) );
/* Update and write out header */
if ( ( rc = bzimage_write_header ( image, &load_ctx, &bzhdr ) ) != 0 )
return rc;
/* 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;
exec_ctx.bz.kernel_seg = load_ctx.rm_kernel_seg;
exec_ctx.bz.stack = load_ctx.rm_heap;
image->priv.ul = exec_ctx.ul;
return 0;
}

25
src/arch/i386/include/bzimage.h
View File

@ -76,17 +76,30 @@ struct bzimage_header {
/** bzImage "load high" flag */
#define BZI_LOAD_HIGH 0x01
/** Load address for high-loaded kernels */
#define BZI_LOAD_HIGH_ADDR 0x100000
/** Load address for low-loaded kernels */
#define BZI_LOAD_LOW_ADDR 0x10000
/** bzImage "kernel can use heap" flag */
#define BZI_CAN_USE_HEAP 0x80
/** bzImage command-line structure used by older kernels */
struct bzimage_cmdline {
/** Magic signature */
uint16_t magic;
/** Offset to command line */
uint16_t offset;
} __attribute__ (( packed ));
/** Offset of bzImage command-line structure within kernel image */
#define BZI_CMDLINE_OFFSET 0x20
/** bzImage command line present magic marker value */
#define BZI_CMD_LINE_MAGIC 0xa33f
#define BZI_CMDLINE_MAGIC 0xa33f
/** bzImage command line present magic marker offset */
#define BZI_CMD_LINE_MAGIC_OFFSET 0x20
/** bzImage command line offset offset */
#define BZI_CMD_LINE_OFFSET_OFFSET 0x22
/** Amount of stack space to provide */
#define BZI_STACK_SIZE 0x1000