elfboot.c File Reference

ELF bootable image. More...

#include <string.h>
#include <errno.h>
#include <elf.h>
#include <librm.h>
#include <ipxe/image.h>
#include <ipxe/elf.h>
#include <ipxe/features.h>
#include <ipxe/init.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FEATURE (FEATURE_IMAGE, "ELF", DHCP_EB_FEATURE_ELF, 1)
static int	elfboot_exec (struct image *image)
	Execute ELF image.
static int	elfboot_check_segment (struct image *image, const Elf_Phdr *phdr, physaddr_t dest)
	Check that ELF segment uses flat physical addressing.
static int	elfboot_probe (struct image *image)
	Probe ELF image.
struct image_type elfboot_image_type	__image_type (PROBE_NORMAL)
	ELF image type.

Detailed Description

ELF bootable image.

Definition in file elfboot.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FEATURE()

FEATURE	(	FEATURE_IMAGE	,
		"ELF"	,
		DHCP_EB_FEATURE_ELF	,
		1	)

References DHCP_EB_FEATURE_ELF, and FEATURE_IMAGE.

elfboot_exec()

int elfboot_exec ( struct image * image )

static

Execute ELF image.

Parameters

image

ELF image

Return values

rc	Return status code

Definition at line 50 of file elfboot.c.

                                                {
        physaddr_t entry;
        physaddr_t max;
        int rc;
 
        /* Load the image using core ELF support */
        if ( ( rc = elf_load ( image, &entry, &max ) ) != 0 ) {
                DBGC ( image, "ELF %s could not load: %s\n",
                       image->name, strerror ( rc ) );
                return rc;
        }
 
        /* An ELF image has no callback interface, so we need to shut
         * down before invoking it.
         */
        shutdown_boot();
 
        /* Jump to OS with flat physical addressing */
        DBGC ( image, "ELF %s starting execution at %lx\n",
               image->name, entry );
        __asm__ __volatile__ ( PHYS_CODE ( "pushl %%ebp\n\t" /* gcc bug */
                                           "call *%%edi\n\t"
                                           "popl %%ebp\n\t" /* gcc bug */ )
                               : : "D" ( entry )
                               : "eax", "ebx", "ecx", "edx", "esi", "memory" );
 
        DBGC ( image, "ELF %s returned\n", image->name );
 
        /* It isn't safe to continue after calling shutdown() */
        while ( 1 ) {}
 
        return -ECANCELED;  /* -EIMPOSSIBLE, anyone? */
}

References __asm__(), __volatile__(), DBGC, ECANCELED, elf_load(), max, image::name, PHYS_CODE, rc, shutdown_boot(), and strerror().

Referenced by __image_type().

elfboot_check_segment()

int elfboot_check_segment ( struct image * image, const Elf_Phdr * phdr, physaddr_t dest )

static

Check that ELF segment uses flat physical addressing.

Parameters

image	ELF file
phdr	ELF program header
dest	Destination address

Return values

rc	Return status code

Definition at line 92 of file elfboot.c.

                                                     {
 
        /* Check that ELF segment uses flat physical addressing */
        if ( phdr->p_vaddr != dest ) {
                DBGC ( image, "ELF %s uses virtual addressing (phys %x, virt "
                       "%x)\n", image->name, phdr->p_paddr, phdr->p_vaddr );
                return -ENOEXEC;
        }
 
        return 0;
}

References DBGC, dest, ENOEXEC, image::name, Elf32_Phdr::p_paddr, and Elf32_Phdr::p_vaddr.

Referenced by elfboot_probe().

elfboot_probe()

int elfboot_probe ( struct image * image )

static

Probe ELF image.

Parameters

image

ELF file

Return values

rc	Return status code

Definition at line 111 of file elfboot.c.

                                                 {
        const Elf32_Ehdr *ehdr;
        static const uint8_t e_ident[] = {
                [EI_MAG0]        = ELFMAG0,
                [EI_MAG1]        = ELFMAG1,
                [EI_MAG2]        = ELFMAG2,
                [EI_MAG3]        = ELFMAG3,
                [EI_CLASS]      = ELFCLASS32,
                [EI_DATA]        = ELFDATA2LSB,
                [EI_VERSION]  = EV_CURRENT,
        };
        physaddr_t entry;
        physaddr_t max;
        int rc;
 
        /* Read ELF header */
        if ( image->len < sizeof ( *ehdr ) ) {
                DBGC ( image, "ELF %s too short for ELF header\n",
                       image->name );
                return -ENOEXEC;
        }
        ehdr = image->data;
        if ( memcmp ( ehdr->e_ident, e_ident, sizeof ( e_ident ) ) != 0 ) {
                DBGC ( image, "ELF %s invalid identifier\n", image->name );
                return -ENOEXEC;
        }
 
        /* Check that this image uses flat physical addressing */
        if ( ( rc = elf_segments ( image, ehdr, elfboot_check_segment,
                                   &entry, &max ) ) != 0 ) {
                DBGC ( image, "ELF %s is not loadable: %s\n",
                       image->name, strerror ( rc ) );
                return rc;
        }
 
        return 0;
}

References image::data, DBGC, Elf32_Ehdr::e_ident, EI_CLASS, EI_DATA, EI_MAG0, EI_MAG1, EI_MAG2, EI_MAG3, EI_VERSION, elf_segments(), elfboot_check_segment(), ELFCLASS32, ELFDATA2LSB, ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3, ENOEXEC, EV_CURRENT, image::len, max, memcmp(), image::name, rc, and strerror().

Referenced by __image_type().

__image_type()

struct image_type elfboot_image_type __image_type

(

PROBE_NORMAL

)

ELF image type.

References __image_type, elfboot_exec(), elfboot_probe(), and PROBE_NORMAL.