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/** @file
This program generates a hex array to be manually coppied into
OvmfXen.fdf.
The purpose is for the flash device image to be recognize as an ELF.
Copyright (c) 2019, Citrix Systems, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "elf.h"
#include "stdio.h"
#include "stddef.h"
void print_hdr(void *s, size_t size)
{
char *c = s;
while (size--) {
printf("0x%02hhx, ", *(c++));
}
}
/* Format for the XEN_ELFNOTE_PHYS32_ENTRY program segment */
#define XEN_ELFNOTE_PHYS32_ENTRY 18
typedef struct {
uint32_t name_size;
uint32_t desc_size;
uint32_t type;
char name[4];
uint32_t desc;
} xen_elfnote_phys32_entry;
int main(void)
{
/* FW_SIZE */
size_t ovmf_blob_size = 0x00200000;
/* Load OVMF at 1MB when running as PVH guest */
uint32_t ovmf_base_address = 0x00100000;
/* Xen PVH entry point */
uint32_t ovmfxen_pvh_entry_point = ovmf_base_address + ovmf_blob_size - 0x30;
size_t offset_into_file = 0;
/* ELF file header */
Elf32_Ehdr hdr = {
.e_ident = ELFMAG,
.e_type = ET_EXEC,
.e_machine = EM_386,
.e_version = EV_CURRENT,
.e_entry = ovmfxen_pvh_entry_point,
.e_flags = R_386_NONE,
.e_ehsize = sizeof (hdr),
.e_phentsize = sizeof (Elf32_Phdr),
};
offset_into_file += sizeof (hdr);
hdr.e_ident[EI_CLASS] = ELFCLASS32;
hdr.e_ident[EI_DATA] = ELFDATA2LSB;
hdr.e_ident[EI_VERSION] = EV_CURRENT;
hdr.e_ident[EI_OSABI] = ELFOSABI_LINUX;
/* Placing program headers just after hdr */
hdr.e_phoff = sizeof (hdr);
/* program header */
Elf32_Phdr phdr_load = {
.p_type = PT_LOAD,
.p_offset = 0, /* load everything */
.p_paddr = ovmf_base_address,
.p_filesz = ovmf_blob_size,
.p_memsz = ovmf_blob_size,
.p_flags = PF_X | PF_W | PF_R,
.p_align = 0,
};
phdr_load.p_vaddr = phdr_load.p_paddr;
hdr.e_phnum += 1;
offset_into_file += sizeof (phdr_load);
/* Xen ELF Note. */
xen_elfnote_phys32_entry xen_elf_note = {
.type = XEN_ELFNOTE_PHYS32_ENTRY,
.name = "Xen",
.desc = ovmfxen_pvh_entry_point,
.name_size =
offsetof (xen_elfnote_phys32_entry, desc) -
offsetof (xen_elfnote_phys32_entry, name),
.desc_size =
sizeof (xen_elfnote_phys32_entry) -
offsetof (xen_elfnote_phys32_entry, desc),
};
Elf32_Phdr phdr_note = {
.p_type = PT_NOTE,
.p_filesz = sizeof (xen_elf_note),
.p_memsz = sizeof (xen_elf_note),
.p_flags = PF_R,
.p_align = 0,
};
hdr.e_phnum += 1;
offset_into_file += sizeof (phdr_note);
phdr_note.p_offset = offset_into_file;
phdr_note.p_paddr = ovmf_base_address + phdr_note.p_offset;
phdr_note.p_vaddr = phdr_note.p_paddr;
/*
* print elf header
*/
size_t i;
size_t hdr_size = sizeof (hdr);
size_t entry_off = offsetof(typeof(hdr), e_entry);
printf("# ELF file header\n");
print_hdr(&hdr, entry_off);
printf("\n");
print_hdr(&hdr.e_entry, sizeof (hdr.e_entry));
printf(" # hdr.e_entry\n");
print_hdr(&hdr.e_entry + 1, hdr_size - entry_off - sizeof (hdr.e_entry));
printf("\n\n# ELF Program segment headers\n");
printf("# - Load segment\n");
for (i = 0; i < sizeof (phdr_load); i += 4) {
print_hdr(((char*)&phdr_load) + i, 4);
printf("\n");
}
printf("# - ELFNOTE segment\n");
for (i = 0; i < sizeof (phdr_note); i += 4) {
print_hdr(((char*)&phdr_note) + i, 4);
printf("\n");
}
printf("\n# XEN_ELFNOTE_PHYS32_ENTRY\n");
for (i = 0; i < sizeof (xen_elf_note); i += 4) {
print_hdr(((char*)&xen_elf_note) + i, 4);
printf("\n");
}
return 0;
}
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