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a71d876801
The logic to decide if an input relocation for a symbol becomes a particular kind of output relocation is one of the hard to maintain parts of the bfd ld backend, since it is partially repeated across elfNN_aarch64_check_relocs (where dynamic relocations are counted per symbol and input section), elfNN_aarch64_late_size_sections (where relocation sections are sized and GOT offsets assigned), elfNN_aarch64_relocate_section (where most relocations are applied and output to a relocation section), elfNN_aarch64_finish_dynamic_symbol (where some of the GOT relocations are applied and output). The DT_RELR support adds another layer to this complexity: after the output relocation sections are sized, so all dynamic relocations are accounted (in elfNN_aarch64_late_size_sections), we scan the symbols and input relocations again to decide which ones become relative relocations that can be packed. The sizes of the relocation sections are updated accordingly. This logic must be consistent with the code that applies the relocs later so each relative relocation is emitted exactly once: either in .rela.* or packed in .relr.dyn. Sizing of .relr.dyn is done via elfNN_aarch64_size_relative_relocs that may be called repeatedly whenever the layout changes since an address change can affect the size of the packed format. Then the final content is emitted in elfNN_aarch64_finish_relative_relocs, that is called after the layout is final and before relocations are applied and emitted. These hooks are only called if DT_RELR is enabled. We only pack relative relocs that are known to be aligned in the output during .relr.dyn sizing, the potentially unaligned relative relocs are emitted normally (in .rela.*, not packed), because the format requires aligned addresses.
170 lines
5.8 KiB
C
170 lines
5.8 KiB
C
/* AArch64-specific backend routines.
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Copyright (C) 2009-2024 Free Software Foundation, Inc.
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Contributed by ARM Ltd.
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This file is part of BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING3. If not,
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see <http://www.gnu.org/licenses/>. */
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extern void bfd_elf64_aarch64_init_maps
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(bfd *);
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extern void bfd_elf32_aarch64_init_maps
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(bfd *);
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/* Types of PLTs based on the level of security. This would be a
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bit-mask to denote which of the combinations of security features
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are enabled:
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- No security feature PLTs
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- PLTs with BTI instruction
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- PLTs with PAC instruction
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*/
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typedef enum
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{
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PLT_NORMAL = 0x0, /* Normal plts. */
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PLT_BTI = 0x1, /* plts with bti. */
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PLT_PAC = 0x2, /* plts with pointer authentication. */
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PLT_BTI_PAC = PLT_BTI | PLT_PAC
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} aarch64_plt_type;
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/* To indicate if BTI is enabled with/without warning. */
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typedef enum
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{
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BTI_NONE = 0, /* BTI is not enabled. */
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BTI_WARN = 1, /* BTI is enabled with -z force-bti. */
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} aarch64_enable_bti_type;
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/* A structure to encompass all information coming from BTI or PAC
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related command line options. This involves the "PLT_TYPE" to determine
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which version of PLTs to pick and "BTI_TYPE" to determine if
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BTI should be turned on with any warnings. */
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typedef struct
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{
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aarch64_plt_type plt_type;
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aarch64_enable_bti_type bti_type;
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} aarch64_bti_pac_info;
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/* An enum to define what kind of erratum fixes we should apply. This gives the
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user a bit more control over the sequences we generate. */
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typedef enum
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{
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ERRAT_NONE = (1 << 0), /* No erratum workarounds allowed. */
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ERRAT_ADR = (1 << 1), /* Erratum workarounds using ADR allowed. */
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ERRAT_ADRP = (1 << 2), /* Erratum workarounds using ADRP are allowed. */
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} erratum_84319_opts;
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extern void bfd_elf64_aarch64_set_options
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(bfd *, struct bfd_link_info *, int, int, int, int, erratum_84319_opts, int,
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aarch64_bti_pac_info);
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extern void bfd_elf32_aarch64_set_options
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(bfd *, struct bfd_link_info *, int, int, int, int, erratum_84319_opts, int,
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aarch64_bti_pac_info);
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/* AArch64 stub generation support for ELF64. Called from the linker. */
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extern int elf64_aarch64_setup_section_lists
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(bfd *, struct bfd_link_info *);
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extern void elf64_aarch64_next_input_section
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(struct bfd_link_info *, struct bfd_section *);
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extern bool elf64_aarch64_size_stubs
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(bfd *, bfd *, struct bfd_link_info *, bfd_signed_vma,
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struct bfd_section * (*) (const char *, struct bfd_section *),
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void (*) (void));
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extern bool elf64_aarch64_build_stubs
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(struct bfd_link_info *);
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/* AArch64 stub generation support for ELF32. Called from the linker. */
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extern int elf32_aarch64_setup_section_lists
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(bfd *, struct bfd_link_info *);
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extern void elf32_aarch64_next_input_section
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(struct bfd_link_info *, struct bfd_section *);
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extern bool elf32_aarch64_size_stubs
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(bfd *, bfd *, struct bfd_link_info *, bfd_signed_vma,
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struct bfd_section * (*) (const char *, struct bfd_section *),
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void (*) (void));
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extern bool elf32_aarch64_build_stubs
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(struct bfd_link_info *);
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/* AArch64 relative relocation packing support for ELF64. */
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extern bool elf64_aarch64_size_relative_relocs
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(struct bfd_link_info *, bool *);
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extern bool elf64_aarch64_finish_relative_relocs
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(struct bfd_link_info *);
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/* AArch64 relative relocation packing support for ELF32. */
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extern bool elf32_aarch64_size_relative_relocs
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(struct bfd_link_info *, bool *);
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extern bool elf32_aarch64_finish_relative_relocs
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(struct bfd_link_info *);
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/* Take the PAGE component of an address or offset. */
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#define PG(x) ((x) & ~ (bfd_vma) 0xfff)
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#define PG_OFFSET(x) ((x) & (bfd_vma) 0xfff)
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#define AARCH64_ADR_OP 0x10000000
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#define AARCH64_ADRP_OP 0x90000000
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#define AARCH64_ADRP_OP_MASK 0x9F000000
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extern bfd_signed_vma
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_bfd_aarch64_sign_extend (bfd_vma, int);
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extern uint32_t
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_bfd_aarch64_decode_adrp_imm (uint32_t);
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extern uint32_t
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_bfd_aarch64_reencode_adr_imm (uint32_t, uint32_t);
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extern bfd_reloc_status_type
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_bfd_aarch64_elf_put_addend (bfd *, bfd_byte *, bfd_reloc_code_real_type,
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reloc_howto_type *, bfd_signed_vma);
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extern bfd_vma
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_bfd_aarch64_elf_resolve_relocation (bfd *, bfd_reloc_code_real_type, bfd_vma,
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bfd_vma, bfd_vma, bool);
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extern bool
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_bfd_aarch64_elf_grok_prstatus (bfd *, Elf_Internal_Note *);
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extern bool
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_bfd_aarch64_elf_grok_psinfo (bfd *, Elf_Internal_Note *);
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extern char *
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_bfd_aarch64_elf_write_core_note (bfd *, char *, int *, int, ...);
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#define elf_backend_grok_prstatus _bfd_aarch64_elf_grok_prstatus
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#define elf_backend_grok_psinfo _bfd_aarch64_elf_grok_psinfo
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#define elf_backend_write_core_note _bfd_aarch64_elf_write_core_note
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extern bfd *
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_bfd_aarch64_elf_link_setup_gnu_properties (struct bfd_link_info *,
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uint32_t *);
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extern enum elf_property_kind
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_bfd_aarch64_elf_parse_gnu_properties (bfd *, unsigned int,
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bfd_byte *, unsigned int);
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extern bool
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_bfd_aarch64_elf_merge_gnu_properties (struct bfd_link_info *, bfd *,
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elf_property *, elf_property *,
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uint32_t);
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extern void
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_bfd_aarch64_elf_link_fixup_gnu_properties (struct bfd_link_info *,
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elf_property_list **);
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#define elf_backend_parse_gnu_properties \
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_bfd_aarch64_elf_parse_gnu_properties
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#define elf_backend_fixup_gnu_properties \
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_bfd_aarch64_elf_link_fixup_gnu_properties
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