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[bzimage] Remove userptr_t from bzImage parsing

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Simplify bzImage parsing by assuming that the various headers are
directly accessible via pointer dereferences.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2025-04-28 16:30:35 +01:00
parent 412ad56012
commit 6ccb6bcfc8
1 changed files with 72 additions and 92 deletions
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164
src/arch/x86/image/bzimage.c
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@@ -32,6 +32,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h> #include <stdint.h>
#include <stdlib.h> #include <stdlib.h>
#include <stdio.h>
#include <string.h> #include <string.h>
#include <errno.h> #include <errno.h>
#include <assert.h> #include <assert.h>
@@ -56,7 +57,7 @@ struct bzimage_context {
/** Real-mode kernel portion load segment address */ /** Real-mode kernel portion load segment address */
unsigned int rm_kernel_seg; unsigned int rm_kernel_seg;
/** Real-mode kernel portion load address */ /** Real-mode kernel portion load address */
userptr_t rm_kernel; void *rm_kernel;
/** Real-mode kernel portion file size */ /** Real-mode kernel portion file size */
size_t rm_filesz; size_t rm_filesz;
/** Real-mode heap top (offset from rm_kernel) */ /** Real-mode heap top (offset from rm_kernel) */
@@ -68,7 +69,7 @@ struct bzimage_context {
/** Real-mode kernel portion total memory size */ /** Real-mode kernel portion total memory size */
size_t rm_memsz; size_t rm_memsz;
/** Non-real-mode kernel portion load address */ /** Non-real-mode kernel portion load address */
userptr_t pm_kernel; void *pm_kernel;
/** Non-real-mode kernel portion file and memory size */ /** Non-real-mode kernel portion file and memory size */
size_t pm_sz; size_t pm_sz;
/** Video mode */ /** Video mode */
@@ -79,11 +80,6 @@ struct bzimage_context {
physaddr_t ramdisk_image; physaddr_t ramdisk_image;
/** Initrd size */ /** Initrd size */
physaddr_t ramdisk_size; physaddr_t ramdisk_size;
/** Command line magic block */
struct bzimage_cmdline cmdline_magic;
/** bzImage header */
struct bzimage_header bzhdr;
}; };
/** /**
@@ -91,32 +87,28 @@ struct bzimage_context {
* *
* @v image bzImage file * @v image bzImage file
* @v bzimg bzImage context * @v bzimg bzImage context
* @v src bzImage to parse
* @ret rc Return status code * @ret rc Return status code
*/ */
static int bzimage_parse_header ( struct image *image, static int bzimage_parse_header ( struct image *image,
struct bzimage_context *bzimg, struct bzimage_context *bzimg ) {
userptr_t src ) { const struct bzimage_header *bzhdr;
unsigned int syssize; unsigned int syssize;
int is_bzimage; int is_bzimage;
/* Initialise context */
memset ( bzimg, 0, sizeof ( *bzimg ) );
/* Sanity check */ /* Sanity check */
if ( image->len < ( BZI_HDR_OFFSET + sizeof ( bzimg->bzhdr ) ) ) { if ( image->len < ( BZI_HDR_OFFSET + sizeof ( *bzhdr ) ) ) {
DBGC ( image, "bzImage %s too short for kernel header\n", DBGC ( image, "bzImage %s too short for kernel header\n",
image->name ); image->name );
return -ENOEXEC; return -ENOEXEC;
} }
bzhdr = ( image->data + BZI_HDR_OFFSET );
/* Read in header structures */
memset ( bzimg, 0, sizeof ( *bzimg ) );
copy_from_user ( &bzimg->cmdline_magic, src, BZI_CMDLINE_OFFSET,
sizeof ( bzimg->cmdline_magic ) );
copy_from_user ( &bzimg->bzhdr, src, BZI_HDR_OFFSET,
sizeof ( bzimg->bzhdr ) );
/* Calculate size of real-mode portion */ /* Calculate size of real-mode portion */
bzimg->rm_filesz = ( ( ( bzimg->bzhdr.setup_sects ? bzimg->rm_filesz = ( ( ( bzhdr->setup_sects ?
bzimg->bzhdr.setup_sects : 4 ) + 1 ) << 9 ); bzhdr->setup_sects : 4 ) + 1 ) << 9 );
if ( bzimg->rm_filesz > image->len ) { if ( bzimg->rm_filesz > image->len ) {
DBGC ( image, "bzImage %s too short for %zd byte of setup\n", DBGC ( image, "bzImage %s too short for %zd byte of setup\n",
image->name, bzimg->rm_filesz ); image->name, bzimg->rm_filesz );
@@ -129,14 +121,14 @@ static int bzimage_parse_header ( struct image *image,
syssize = ( ( bzimg->pm_sz + 15 ) / 16 ); syssize = ( ( bzimg->pm_sz + 15 ) / 16 );
/* Check for signatures and determine version */ /* Check for signatures and determine version */
if ( bzimg->bzhdr.boot_flag != BZI_BOOT_FLAG ) { if ( bzhdr->boot_flag != BZI_BOOT_FLAG ) {
DBGC ( image, "bzImage %s missing 55AA signature\n", DBGC ( image, "bzImage %s missing 55AA signature\n",
image->name ); image->name );
return -ENOEXEC; return -ENOEXEC;
} }
if ( bzimg->bzhdr.header == BZI_SIGNATURE ) { if ( bzhdr->header == BZI_SIGNATURE ) {
/* 2.00+ */ /* 2.00+ */
bzimg->version = bzimg->bzhdr.version; bzimg->version = bzhdr->version;
} else { } else {
/* Pre-2.00. Check that the syssize field is correct, /* Pre-2.00. Check that the syssize field is correct,
* as a guard against accepting arbitrary binary data, * as a guard against accepting arbitrary binary data,
@@ -146,9 +138,9 @@ static int bzimage_parse_header ( struct image *image,
* check this field. * check this field.
*/ */
bzimg->version = 0x0100; bzimg->version = 0x0100;
if ( bzimg->bzhdr.syssize != syssize ) { if ( bzhdr->syssize != syssize ) {
DBGC ( image, "bzImage %s bad syssize %x (expected " DBGC ( image, "bzImage %s bad syssize %x (expected "
"%x)\n", image->name, bzimg->bzhdr.syssize, "%x)\n", image->name, bzhdr->syssize,
syssize ); syssize );
return -ENOEXEC; return -ENOEXEC;
} }
@@ -156,7 +148,7 @@ static int bzimage_parse_header ( struct image *image,
/* Determine image type */ /* Determine image type */
is_bzimage = ( ( bzimg->version >= 0x0200 ) ? is_bzimage = ( ( bzimg->version >= 0x0200 ) ?
( bzimg->bzhdr.loadflags & BZI_LOAD_HIGH ) : 0 ); ( bzhdr->loadflags & BZI_LOAD_HIGH ) : 0 );
/* Calculate load address of real-mode portion */ /* Calculate load address of real-mode portion */
bzimg->rm_kernel_seg = ( is_bzimage ? 0x1000 : 0x9000 ); bzimg->rm_kernel_seg = ( is_bzimage ? 0x1000 : 0x9000 );
@@ -175,15 +167,15 @@ static int bzimage_parse_header ( struct image *image,
: BZI_LOAD_LOW_ADDR ); : BZI_LOAD_LOW_ADDR );
/* Extract video mode */ /* Extract video mode */
bzimg->vid_mode = bzimg->bzhdr.vid_mode; bzimg->vid_mode = bzhdr->vid_mode;
/* Extract memory limit */ /* Extract memory limit */
bzimg->mem_limit = ( ( bzimg->version >= 0x0203 ) ? bzimg->mem_limit = ( ( bzimg->version >= 0x0203 ) ?
bzimg->bzhdr.initrd_addr_max : BZI_INITRD_MAX ); bzhdr->initrd_addr_max : BZI_INITRD_MAX );
/* Extract command line size */ /* Extract command line size */
bzimg->cmdline_size = ( ( bzimg->version >= 0x0206 ) ? bzimg->cmdline_size = ( ( bzimg->version >= 0x0206 ) ?
bzimg->bzhdr.cmdline_size : BZI_CMDLINE_SIZE ); bzhdr->cmdline_size : BZI_CMDLINE_SIZE );
DBGC ( image, "bzImage %s version %04x RM %#lx+%#zx PM %#lx+%#zx " DBGC ( image, "bzImage %s version %04x RM %#lx+%#zx PM %#lx+%#zx "
"cmdlen %zd\n", image->name, bzimg->version, "cmdlen %zd\n", image->name, bzimg->version,
@@ -199,50 +191,44 @@ static int bzimage_parse_header ( struct image *image,
* *
* @v image bzImage file * @v image bzImage file
* @v bzimg bzImage context * @v bzimg bzImage context
* @v dst bzImage to update
*/ */
static void bzimage_update_header ( struct image *image, static void bzimage_update_header ( struct image *image,
struct bzimage_context *bzimg, struct bzimage_context *bzimg ) {
userptr_t dst ) { struct bzimage_header *bzhdr = ( bzimg->rm_kernel + BZI_HDR_OFFSET );
struct bzimage_cmdline *cmdline;
/* Set loader type */ /* Set loader type */
if ( bzimg->version >= 0x0200 ) if ( bzimg->version >= 0x0200 )
bzimg->bzhdr.type_of_loader = BZI_LOADER_TYPE_IPXE; bzhdr->type_of_loader = BZI_LOADER_TYPE_IPXE;
/* Set heap end pointer */ /* Set heap end pointer */
if ( bzimg->version >= 0x0201 ) { if ( bzimg->version >= 0x0201 ) {
bzimg->bzhdr.heap_end_ptr = ( bzimg->rm_heap - 0x200 ); bzhdr->heap_end_ptr = ( bzimg->rm_heap - 0x200 );
bzimg->bzhdr.loadflags |= BZI_CAN_USE_HEAP; bzhdr->loadflags |= BZI_CAN_USE_HEAP;
} }
/* Set command line */ /* Set command line */
if ( bzimg->version >= 0x0202 ) { if ( bzimg->version >= 0x0202 ) {
bzimg->bzhdr.cmd_line_ptr = ( virt_to_phys ( bzimg->rm_kernel ) bzhdr->cmd_line_ptr = ( virt_to_phys ( bzimg->rm_kernel )
+ bzimg->rm_cmdline ); + bzimg->rm_cmdline );
} else { } else {
bzimg->cmdline_magic.magic = BZI_CMDLINE_MAGIC; cmdline = ( bzimg->rm_kernel + BZI_CMDLINE_OFFSET );
bzimg->cmdline_magic.offset = bzimg->rm_cmdline; cmdline->magic = BZI_CMDLINE_MAGIC;
cmdline->offset = bzimg->rm_cmdline;
if ( bzimg->version >= 0x0200 ) if ( bzimg->version >= 0x0200 )
bzimg->bzhdr.setup_move_size = bzimg->rm_memsz; bzhdr->setup_move_size = bzimg->rm_memsz;
} }
/* Set video mode */ /* Set video mode */
bzimg->bzhdr.vid_mode = bzimg->vid_mode; bzhdr->vid_mode = bzimg->vid_mode;
DBGC ( image, "bzImage %s vidmode %d\n",
image->name, bzhdr->vid_mode );
/* Set initrd address */ /* Set initrd address */
if ( bzimg->version >= 0x0200 ) { if ( bzimg->version >= 0x0200 ) {
bzimg->bzhdr.ramdisk_image = bzimg->ramdisk_image; bzhdr->ramdisk_image = bzimg->ramdisk_image;
bzimg->bzhdr.ramdisk_size = bzimg->ramdisk_size; bzhdr->ramdisk_size = bzimg->ramdisk_size;
} }
/* Write out header structures */
copy_to_user ( dst, BZI_CMDLINE_OFFSET, &bzimg->cmdline_magic,
sizeof ( bzimg->cmdline_magic ) );
copy_to_user ( dst, BZI_HDR_OFFSET, &bzimg->bzhdr,
sizeof ( bzimg->bzhdr ) );
DBGC ( image, "bzImage %s vidmode %d\n",
image->name, bzimg->vid_mode );
} }
/** /**
@@ -321,16 +307,13 @@ static int bzimage_parse_cmdline ( struct image *image,
static void bzimage_set_cmdline ( struct image *image, static void bzimage_set_cmdline ( struct image *image,
struct bzimage_context *bzimg ) { struct bzimage_context *bzimg ) {
const char *cmdline = ( image->cmdline ? image->cmdline : "" ); const char *cmdline = ( image->cmdline ? image->cmdline : "" );
size_t cmdline_len; char *rm_cmdline;
/* Copy command line down to real-mode portion */ /* Copy command line down to real-mode portion */
cmdline_len = ( strlen ( cmdline ) + 1 ); rm_cmdline = ( bzimg->rm_kernel + bzimg->rm_cmdline );
if ( cmdline_len > bzimg->cmdline_size ) snprintf ( rm_cmdline, bzimg->cmdline_size, "%s", cmdline );
cmdline_len = bzimg->cmdline_size;
copy_to_user ( bzimg->rm_kernel, bzimg->rm_cmdline,
cmdline, cmdline_len );
DBGC ( image, "bzImage %s command line \"%s\"\n", DBGC ( image, "bzImage %s command line \"%s\"\n",
image->name, cmdline ); image->name, rm_cmdline );
} }
/** /**
@@ -349,12 +332,12 @@ static inline size_t bzimage_align ( size_t len ) {
* *
* @v image bzImage image * @v image bzImage image
* @v initrd initrd image * @v initrd initrd image
* @v address Address at which to load, or UNULL * @v address Address at which to load, or NULL
* @ret len Length of loaded image, excluding zero-padding * @ret len Length of loaded image, excluding zero-padding
*/ */
static size_t bzimage_load_initrd ( struct image *image, static size_t bzimage_load_initrd ( struct image *image,
struct image *initrd, struct image *initrd,
userptr_t address ) { void *address ) {
const char *filename = cpio_name ( initrd ); const char *filename = cpio_name ( initrd );
struct cpio_header cpio; struct cpio_header cpio;
size_t offset; size_t offset;
@@ -379,11 +362,10 @@ static size_t bzimage_load_initrd ( struct image *image,
offset = 0; offset = 0;
for ( i = 0 ; ( cpio_len = cpio_header ( initrd, i, &cpio ) ) ; for ( i = 0 ; ( cpio_len = cpio_header ( initrd, i, &cpio ) ) ;
i++ ) { i++ ) {
copy_to_user ( address, offset, &cpio, memcpy ( ( address + offset ), &cpio,
sizeof ( cpio ) ); sizeof ( cpio ) );
copy_to_user ( address, ( offset + sizeof ( cpio ) ), memcpy ( ( address + offset + sizeof ( cpio ) ),
filename, filename, ( cpio_len - sizeof ( cpio ) ) );
( cpio_len - sizeof ( cpio ) ) );
offset += ( cpio_len + cpio_pad_len ( cpio_len ) ); offset += ( cpio_len + cpio_pad_len ( cpio_len ) );
} }
assert ( offset == len ); assert ( offset == len );
@@ -424,7 +406,7 @@ static int bzimage_check_initrds ( struct image *image,
for_each_image ( initrd ) { for_each_image ( initrd ) {
/* Calculate length */ /* Calculate length */
len += bzimage_load_initrd ( image, initrd, UNULL ); len += bzimage_load_initrd ( image, initrd, NULL );
len = bzimage_align ( len ); len = bzimage_align ( len );
DBGC ( image, "bzImage %s initrd %s from [%#08lx,%#08lx)%s%s\n", DBGC ( image, "bzImage %s initrd %s from [%#08lx,%#08lx)%s%s\n",
@@ -469,34 +451,34 @@ static int bzimage_check_initrds ( struct image *image,
static void bzimage_load_initrds ( struct image *image, static void bzimage_load_initrds ( struct image *image,
struct bzimage_context *bzimg ) { struct bzimage_context *bzimg ) {
struct image *initrd; struct image *initrd;
struct image *highest = NULL;
struct image *other; struct image *other;
userptr_t top; physaddr_t bottom;
userptr_t dest; physaddr_t top;
physaddr_t dest;
size_t offset; size_t offset;
size_t len; size_t len;
/* Reshuffle initrds into desired order */ /* Reshuffle initrds into desired order */
initrd_reshuffle ( virt_to_phys ( bzimg->pm_kernel + bzimg->pm_sz ) ); bottom = virt_to_phys ( bzimg->pm_kernel + bzimg->pm_sz );
initrd_reshuffle ( bottom );
/* Find highest initrd */ /* Find highest usable address */
top = 0;
for_each_image ( initrd ) { for_each_image ( initrd ) {
if ( ( highest == NULL ) || ( initrd->data > highest->data ) ) if ( virt_to_phys ( initrd->data ) >= top ) {
highest = initrd; top = ( virt_to_phys ( initrd->data ) +
bzimage_align ( initrd->len ) );
}
} }
/* Do nothing if there are no initrds */ /* Do nothing if there are no initrds */
if ( ! highest ) if ( ! top )
return; return;
if ( ( top - 1UL ) > bzimg->mem_limit ) {
/* Find highest usable address */ top = ( ( bzimg->mem_limit + 1 ) & ~( INITRD_ALIGN - 1 ) );
top = ( highest->data + bzimage_align ( highest->len ) );
if ( ( virt_to_phys ( top ) - 1UL ) > bzimg->mem_limit ) {
top = phys_to_virt ( ( bzimg->mem_limit + 1 ) &
~( INITRD_ALIGN - 1 ) );
} }
DBGC ( image, "bzImage %s loading initrds from %#08lx downwards\n", DBGC ( image, "bzImage %s loading initrds from %#08lx downwards\n",
image->name, ( virt_to_phys ( top ) - 1UL ) ); image->name, ( top - 1UL ) );
/* Load initrds in order */ /* Load initrds in order */
for_each_image ( initrd ) { for_each_image ( initrd ) {
@@ -508,19 +490,19 @@ static void bzimage_load_initrds ( struct image *image,
for_each_image ( other ) { for_each_image ( other ) {
if ( other == initrd ) if ( other == initrd )
offset = 0; offset = 0;
offset += bzimage_load_initrd ( image, other, UNULL ); offset += bzimage_load_initrd ( image, other, NULL );
offset = bzimage_align ( offset ); offset = bzimage_align ( offset );
} }
/* Load initrd at this address */ /* Load initrd at this address */
dest = ( top - offset ); dest = ( top - offset );
len = bzimage_load_initrd ( image, initrd, dest ); len = bzimage_load_initrd ( image, initrd,
phys_to_virt ( dest ) );
/* Record initrd location */ /* Record initrd location */
if ( ! bzimg->ramdisk_image ) if ( ! bzimg->ramdisk_image )
bzimg->ramdisk_image = virt_to_phys ( dest ); bzimg->ramdisk_image = dest;
bzimg->ramdisk_size = ( virt_to_phys ( dest ) + len - bzimg->ramdisk_size = ( dest + len - bzimg->ramdisk_image );
bzimg->ramdisk_image );
} }
DBGC ( image, "bzImage %s initrds at [%#08lx,%#08lx)\n", DBGC ( image, "bzImage %s initrds at [%#08lx,%#08lx)\n",
image->name, bzimg->ramdisk_image, image->name, bzimg->ramdisk_image,
@@ -538,8 +520,7 @@ static int bzimage_exec ( struct image *image ) {
int rc; int rc;
/* Read and parse header from image */ /* Read and parse header from image */
if ( ( rc = bzimage_parse_header ( image, &bzimg, if ( ( rc = bzimage_parse_header ( image, &bzimg ) ) != 0 )
image->data ) ) != 0 )
return rc; return rc;
/* Prepare segments */ /* Prepare segments */
@@ -584,7 +565,7 @@ static int bzimage_exec ( struct image *image ) {
bzimage_load_initrds ( image, &bzimg ); bzimage_load_initrds ( image, &bzimg );
/* Update kernel header */ /* Update kernel header */
bzimage_update_header ( image, &bzimg, bzimg.rm_kernel ); bzimage_update_header ( image, &bzimg );
DBGC ( image, "bzImage %s jumping to RM kernel at %04x:0000 (stack " DBGC ( image, "bzImage %s jumping to RM kernel at %04x:0000 (stack "
"%04x:%04zx)\n", image->name, ( bzimg.rm_kernel_seg + 0x20 ), "%04x:%04zx)\n", image->name, ( bzimg.rm_kernel_seg + 0x20 ),
@@ -623,8 +604,7 @@ int bzimage_probe ( struct image *image ) {
int rc; int rc;
/* Read and parse header from image */ /* Read and parse header from image */
if ( ( rc = bzimage_parse_header ( image, &bzimg, if ( ( rc = bzimage_parse_header ( image, &bzimg ) ) != 0 )
image->data ) ) != 0 )
return rc; return rc;
return 0; return 0;