util/cbfstool/rmodule.h

   1 /*
   2  * Copyright (C) 2014 Google, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #ifndef TOOL_RMODULE_H
  15 #define TOOL_RMODULE_H
  16
  17 #include "elfparsing.h"
  18 #include "common.h"
  19
  20 struct arch_ops {
  21         int arch;
  22         /* Determine if relocation is a valid type for the architecture. */
  23         int (*valid_type)(Elf64_Rela *rel);
  24         /* Determine if relocation should be emitted. */
  25         int (*should_emit)(Elf64_Rela *rel);
  26 };
  27
  28 /*
  29  * The fields in rmod_context are read-only to the user. These are
  30  * exposed for easy shareability.
  31  */
  32 struct rmod_context {
  33         /* Ops to process relocations. */
  34         const struct arch_ops *ops;
  35
  36         /* endian conversion ops */
  37         struct xdr *xdr;
  38
  39         /* Parsed ELF sturcture. */
  40         struct parsed_elf pelf;
  41         /* Program segment. */
  42         Elf64_Phdr *phdr;
  43
  44         /* Collection of relocation addresses fixup in the module. */
  45         Elf64_Xword nrelocs;
  46         Elf64_Addr *emitted_relocs;
  47
  48         /* The following fields are addresses within the linked program.  */
  49         Elf64_Addr parameters_begin;
  50         Elf64_Addr parameters_end;
  51         Elf64_Addr bss_begin;
  52         Elf64_Addr bss_end;
  53 };
  54
  55 struct reloc_filter {
  56         /* Return < 0 on error. 0 to ignore relocation and 1 to include
  57          * relocation. */
  58         int (*filter)(struct reloc_filter *f, const Elf64_Rela *r);
  59         /* Pointer for filter provides */
  60         void *context;
  61 };
  62
  63 /*
  64  * Parse an ELF file within the elfin buffer and fill in the elfout buffer
  65  * with a created rmodule in ELF format. Return 0 on success, < 0 on error.
  66  */
  67 int rmodule_create(const struct buffer *elfin, struct buffer *elfout);
  68
  69 /*
  70  * Initialize an rmodule context from an ELF buffer. Returns 0 on scucess, < 0
  71  * on error.
  72  */
  73 int rmodule_init(struct rmod_context *ctx, const struct buffer *elfin);
  74
  75 /*
  76  * Collect all the relocations that apply to the program in
  77  * nrelocs/emitted_relocs. One can optionally provide a reloc_filter object
  78  * to help in relocation filtering. The filter function will be called twice:
  79  * once for counting and once for emitting. The same response should be
  80  * provided for each call. Returns 0 on success, < 0 on error.
  81  */
  82 int rmodule_collect_relocations(struct rmod_context *c, struct reloc_filter *f);
  83
  84 /* Clean up the memory consumed by the rmdoule context. */
  85 void rmodule_cleanup(struct rmod_context *ctx);
  86
  87 /*
  88  * Create an ELF file from the passed in rmodule in the buffer. The buffer
  89  * contents will be replaced with an ELF file. Returns 1 if buff doesn't
  90  * contain an rmodule and < 0 on failure, 0 on success.
  91  */
  92 int rmodule_stage_to_elf(Elf64_Ehdr *ehdr, struct buffer *buff);
  93
  94 #endif /* TOOL_RMODULE_H */