OvmfPkg/OvmfXenElfHeaderGenerator.c

   1 /** @file
   2   This program generates a hex array to be manually coppied into
   3   OvmfXen.fdf.
   4
   5   The purpose is for the flash device image to be recognize as an ELF.
   6
   7   Copyright (c) 2019, Citrix Systems, Inc.
   8
   9   SPDX-License-Identifier: BSD-2-Clause-Patent
  10 **/
  11
  12 #include "elf.h"
  13 #include "fcntl.h"
  14 #include "stdbool.h"
  15 #include "stddef.h"
  16 #include "stdio.h"
  17 #include "stdlib.h"
  18
  19 void
  20 print_hdr (
  21   FILE    *file,
  22   void    *s,
  23   size_t  size,
  24   bool    end_delimiter
  25   )
  26 {
  27   char  *c = s;
  28
  29   fprintf (file, "  ");
  30   while (size-- > 1) {
  31     fprintf (file, "0x%02hhx, ", *(c++));
  32   }
  33
  34   if (end_delimiter) {
  35     fprintf (file, "0x%02hhx,", *c);
  36   } else {
  37     fprintf (file, "0x%02hhx", *c);
  38   }
  39 }
  40
  41 /* Format for the XEN_ELFNOTE_PHYS32_ENTRY program segment */
  42 #define XEN_ELFNOTE_PHYS32_ENTRY  18
  43 typedef struct {
  44   uint32_t    name_size;
  45   uint32_t    desc_size;
  46   uint32_t    type;
  47   char        name[4];
  48   uint32_t    desc;
  49 } xen_elfnote_phys32_entry;
  50
  51 #define LICENSE_HDR  "\
  52 ## @file\r\n\
  53 #  FDF include file that defines a PVH ELF header.\r\n\
  54 #\r\n\
  55 #  Copyright (c) 2022, Intel Corporation. All rights reserved.\r\n\
  56 #\r\n\
  57 #  SPDX-License-Identifier: BSD-2-Clause-Patent\r\n\
  58 #\r\n\
  59 ##\r\n\
  60 \r\n\
  61 "
  62
  63 int
  64 main (
  65   int   argc,
  66   char  *argv[]
  67   )
  68 {
  69   /* FW_SIZE */
  70   size_t  ovmf_blob_size = 0x00200000;
  71   /* Load OVMF at 1MB when running as PVH guest */
  72   uint32_t  ovmf_base_address = 0x00100000;
  73   uint32_t  ovmfxen_pvh_entry_point;
  74   size_t    offset_into_file = 0;
  75   char      *endptr, *str;
  76   long      param;
  77   FILE      *file = stdout;
  78
  79   /* Parse the size parameter */
  80   if (argc > 1) {
  81     str   = argv[1];
  82     param = strtol (str, &endptr, 10);
  83     if (endptr != str) {
  84       ovmf_blob_size = (size_t)param;
  85     }
  86   }
  87
  88   /* Parse the filepath parameter */
  89   if (argc > 2) {
  90     file = fopen (argv[2], "w");
  91     fprintf (file, LICENSE_HDR);
  92   }
  93
  94   /* Xen PVH entry point */
  95   ovmfxen_pvh_entry_point = ovmf_base_address + ovmf_blob_size - 0x30;
  96
  97   /* ELF file header */
  98  #ifdef PVH64
  99   Elf64_Ehdr  hdr = {
 100  #else
 101   Elf32_Ehdr  hdr = {
 102  #endif
 103     .e_ident   = ELFMAG,
 104     .e_type    = ET_EXEC,
 105     .e_machine = EM_386,
 106     .e_version = EV_CURRENT,
 107     .e_entry   = ovmfxen_pvh_entry_point,
 108     .e_flags   = R_386_NONE,
 109     .e_ehsize  = sizeof (hdr),
 110  #ifdef PVH64
 111     .e_phentsize = sizeof (Elf64_Phdr),
 112  #else
 113     .e_phentsize = sizeof (Elf32_Phdr),
 114  #endif
 115   };
 116
 117   offset_into_file += sizeof (hdr);
 118
 119  #ifdef PVH64
 120   hdr.e_ident[EI_CLASS] = ELFCLASS64;
 121  #else
 122   hdr.e_ident[EI_CLASS] = ELFCLASS32;
 123  #endif
 124   hdr.e_ident[EI_DATA]    = ELFDATA2LSB;
 125   hdr.e_ident[EI_VERSION] = EV_CURRENT;
 126   hdr.e_ident[EI_OSABI]   = ELFOSABI_LINUX;
 127   /* Placing program headers just after hdr */
 128   hdr.e_phoff = sizeof (hdr);
 129
 130   /* program header */
 131  #ifdef PVH64
 132   Elf64_Phdr  phdr_load = {
 133  #else
 134   Elf32_Phdr  phdr_load = {
 135  #endif
 136     .p_type   = PT_LOAD,
 137     .p_offset = 0, /* load everything */
 138     .p_paddr  = ovmf_base_address,
 139     .p_filesz = ovmf_blob_size,
 140     .p_memsz  = ovmf_blob_size,
 141     .p_flags  = PF_X | PF_W | PF_R,
 142  #ifdef PVH64
 143     .p_align  = 4,
 144  #else
 145     .p_align  = 0,
 146  #endif
 147   };
 148
 149   phdr_load.p_vaddr = phdr_load.p_paddr;
 150   hdr.e_phnum      += 1;
 151   offset_into_file += sizeof (phdr_load);
 152
 153   /* Xen ELF Note. */
 154
 155   xen_elfnote_phys32_entry  xen_elf_note = {
 156     .type      = XEN_ELFNOTE_PHYS32_ENTRY,
 157     .name      = "Xen",
 158     .desc      = ovmfxen_pvh_entry_point,
 159     .name_size =
 160       offsetof (xen_elfnote_phys32_entry, desc) -
 161       offsetof (xen_elfnote_phys32_entry, name),
 162     .desc_size =
 163       sizeof (xen_elfnote_phys32_entry) -
 164       offsetof (xen_elfnote_phys32_entry, desc),
 165   };
 166  #ifdef PVH64
 167   Elf64_Phdr  phdr_note = {
 168  #else
 169   Elf32_Phdr  phdr_note = {
 170  #endif
 171     .p_type   = PT_NOTE,
 172     .p_filesz = sizeof (xen_elf_note),
 173     .p_memsz  = sizeof (xen_elf_note),
 174     .p_flags  = PF_R,
 175  #ifdef PVH64
 176     .p_align  = 4,
 177  #else
 178     .p_align  = 0,
 179  #endif
 180   };
 181
 182   hdr.e_phnum       += 1;
 183   offset_into_file  += sizeof (phdr_note);
 184   phdr_note.p_offset = offset_into_file;
 185   phdr_note.p_paddr  = ovmf_base_address + phdr_note.p_offset;
 186   phdr_note.p_vaddr  = phdr_note.p_paddr;
 187
 188   /*
 189    * print elf header
 190    */
 191
 192   size_t  i;
 193   size_t  hdr_size  = sizeof (hdr);
 194   size_t  entry_off = offsetof (typeof(hdr), e_entry);
 195
 196   fprintf (file, "DATA = {\r\n");
 197
 198   fprintf (file, "  # ELF file header\r\n");
 199   print_hdr (file, &hdr, entry_off, true);
 200   fprintf (file, "\r\n");
 201   print_hdr (file, &hdr.e_entry, sizeof (hdr.e_entry), true);
 202   fprintf (file, " # hdr.e_entry\r\n");
 203   print_hdr (file, &hdr.e_entry + 1, hdr_size - entry_off - sizeof (hdr.e_entry), true);
 204
 205   fprintf (file, "\r\n\r\n  # ELF Program segment headers\r\n");
 206   fprintf (file, "  # - Load segment\r\n");
 207   for (i = 0; i < sizeof (phdr_load); i += 4) {
 208     print_hdr (file, ((char *)&phdr_load) + i, 4, true);
 209     fprintf (file, "\r\n");
 210   }
 211
 212   fprintf (file, "  # - ELFNOTE segment\r\n");
 213   for (i = 0; i < sizeof (phdr_note); i += 4) {
 214     print_hdr (file, ((char *)&phdr_note) + i, 4, true);
 215     fprintf (file, "\r\n");
 216   }
 217
 218   fprintf (file, "\r\n  # XEN_ELFNOTE_PHYS32_ENTRY\r\n");
 219   for (i = 0; i < sizeof (xen_elf_note); i += 4) {
 220     print_hdr (file, ((char *)&xen_elf_note) + i, 4, (sizeof (xen_elf_note) - i) > 4);
 221     fprintf (file, "\r\n");
 222   }
 223
 224   fprintf (file, "}\r\n");
 225
 226   return 0;
 227 }