/* x86 specific support for ELF
- Copyright (C) 2017 Free Software Foundation, Inc.
+ Copyright (C) 2017-2020 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
#include "bfdlink.h"
#include "libbfd.h"
#include "elf-bfd.h"
-#include "bfd_stdint.h"
#include "hashtab.h"
+#include "elf-linker-x86.h"
#define PLT_CIE_LENGTH 20
#define PLT_FDE_LENGTH 36
into the shared library. However, if we are linking with -Bsymbolic,
we do not need to copy a reloc against a global symbol which is
defined in an object we are including in the link (i.e., DEF_REGULAR
- is set). At this point we have not seen all the input files, so it
- is possible that DEF_REGULAR is not set now but will be set later (it
- is never cleared). In case of a weak definition, DEF_REGULAR may be
- cleared later by a strong definition in a shared library. We account
- for that possibility below by storing information in the relocs_copied
- field of the hash table entry. A similar situation occurs when
- creating shared libraries and symbol visibility changes render the
- symbol local.
+ is set).
+
+ If PCREL_PLT is true, don't generate dynamic relocation in PIE for
+ PC-relative relocation against a dynamic function definition in data
+ section when PLT address can be used.
If on the other hand, we are creating an executable, we may need to
keep relocations for symbols satisfied by a dynamic library if we
We also need to generate dynamic pointer relocation against
STT_GNU_IFUNC symbol in the non-code section. */
-#define NEED_DYNAMIC_RELOCATION_P(INFO, H, SEC, R_TYPE, POINTER_TYPE) \
+#define NEED_DYNAMIC_RELOCATION_P(INFO, PCREL_PLT, H, SEC, R_TYPE, \
+ POINTER_TYPE) \
((bfd_link_pic (INFO) \
&& (! X86_PCREL_TYPE_P (R_TYPE) \
|| ((H) != NULL \
&& (! (bfd_link_pie (INFO) \
|| SYMBOLIC_BIND ((INFO), (H))) \
|| (H)->root.type == bfd_link_hash_defweak \
- || !(H)->def_regular)))) \
- || ((H) != NULL \
- && (H)->type == STT_GNU_IFUNC \
- && (R_TYPE) == POINTER_TYPE \
- && ((SEC)->flags & SEC_CODE) == 0) \
- || (ELIMINATE_COPY_RELOCS \
- && !bfd_link_pic (INFO) \
- && (H) != NULL \
- && ((H)->root.type == bfd_link_hash_defweak \
- || !(H)->def_regular)))
+ || (!(bfd_link_pie (INFO) \
+ && (PCREL_PLT) \
+ && (H)->plt.refcount > 0 \
+ && ((SEC)->flags & SEC_CODE) == 0 \
+ && (H)->type == STT_FUNC \
+ && (H)->def_dynamic) \
+ && !(H)->def_regular))))) \
+ || ((H) != NULL \
+ && (H)->type == STT_GNU_IFUNC \
+ && (R_TYPE) == POINTER_TYPE \
+ && ((SEC)->flags & SEC_CODE) == 0) \
+ || (ELIMINATE_COPY_RELOCS \
+ && !bfd_link_pic (INFO) \
+ && (H) != NULL \
+ && ((H)->root.type == bfd_link_hash_defweak \
+ || !(H)->def_regular)))
/* TRUE if dynamic relocation should be generated. Don't copy a
pc-relative relocation into the output file if the symbol needs
Copy dynamic function pointer relocations. Don't generate dynamic
relocations against resolved undefined weak symbols in PIE, except
when PC32_RELOC is TRUE. Undefined weak symbol is bound locally
- when PIC is false. */
-#define GENERATE_DYNAMIC_RELOCATION_P(INFO, EH, R_TYPE, \
+ when PIC is false. Don't generate dynamic relocations against
+ non-preemptible absolute symbol. */
+#define GENERATE_DYNAMIC_RELOCATION_P(INFO, EH, R_TYPE, SEC, \
NEED_COPY_RELOC_IN_PIE, \
RESOLVED_TO_ZERO, PC32_RELOC) \
((bfd_link_pic (INFO) \
+ && !(bfd_is_abs_section (SEC) \
+ && ((EH) == NULL \
+ || SYMBOL_REFERENCES_LOCAL (INFO, &(EH)->elf))) \
&& !(NEED_COPY_RELOC_IN_PIE) \
&& ((EH) == NULL \
|| ((ELF_ST_VISIBILITY ((EH)->elf.other) == STV_DEFAULT \
&& (!(RESOLVED_TO_ZERO) || PC32_RELOC)) \
|| (EH)->elf.root.type != bfd_link_hash_undefweak)) \
- && ((!X86_PCREL_TYPE_P (R_TYPE) \
- && !X86_SIZE_TYPE_P (R_TYPE)) \
- || ! SYMBOL_CALLS_LOCAL ((INFO), &(EH)->elf))) \
+ && ((!X86_PCREL_TYPE_P (R_TYPE) && !X86_SIZE_TYPE_P (R_TYPE)) \
+ || ! SYMBOL_CALLS_LOCAL ((INFO), \
+ (struct elf_link_hash_entry *) (EH)))) \
|| (ELIMINATE_COPY_RELOCS \
&& !bfd_link_pic (INFO) \
&& (EH) != NULL \
&& (EH)->elf.dynindx != -1 \
&& (!(EH)->elf.non_got_ref \
- || (EH)->func_pointer_refcount > 0 \
|| ((EH)->elf.root.type == bfd_link_hash_undefweak \
&& !(RESOLVED_TO_ZERO))) \
&& (((EH)->elf.def_dynamic && !(EH)->elf.def_regular) \
|| (ELF_ST_VISIBILITY ((H)->other) \
&& (H)->root.type == bfd_link_hash_undefweak))
+/* TRUE if this symbol isn't defined by a shared object. */
+#define SYMBOL_DEFINED_NON_SHARED_P(H) \
+ ((H)->def_regular \
+ || (H)->root.linker_def \
+ || (H)->root.ldscript_def \
+ || ((struct elf_x86_link_hash_entry *) (H))->linker_def \
+ || ELF_COMMON_DEF_P (H))
+
+/* Return TRUE if the symbol described by a linker hash entry H is
+ going to be absolute. Similar to bfd_is_abs_symbol, but excluding
+ all linker-script defined symbols. */
+#define ABS_SYMBOL_P(H) \
+ (bfd_is_abs_symbol (&(H)->root) && !(H)->root.ldscript_def)
+
/* TRUE if relative relocation should be generated. GOT reference to
global symbol in PIC will lead to dynamic symbol. It becomes a
problem when "time" or "times" is defined as a variable in an
executable, clashing with functions of the same name in libc. If a
symbol isn't undefined weak symbol, don't make it dynamic in PIC and
- generate relative relocation. */
+ generate relative relocation. Don't generate relative relocation
+ against non-preemptible absolute symbol. */
#define GENERATE_RELATIVE_RELOC_P(INFO, H) \
((H)->dynindx == -1 \
&& !(H)->forced_local \
&& (H)->root.type != bfd_link_hash_undefweak \
- && bfd_link_pic (INFO))
+ && bfd_link_pic (INFO) \
+ && !ABS_SYMBOL_P (H))
/* TRUE if this is a pointer reference to a local IFUNC. */
#define POINTER_LOCAL_IFUNC_P(INFO, H) \
{
struct elf_link_hash_entry elf;
- /* Track dynamic relocs copied for this symbol. */
- struct elf_dyn_relocs *dyn_relocs;
-
unsigned char tls_type;
/* Bit 0: Symbol has no GOT nor PLT relocations.
is only used by x86-64. */
unsigned int needs_copy : 1;
- /* Reference count of C/C++ function pointer relocations in read-write
- section which can be resolved at run-time. */
- bfd_signed_vma func_pointer_refcount;
-
/* Information about the GOT PLT entry. Filled when there are both
GOT and PLT relocations against the same function. */
union gotplt_union plt_got;
struct elf_x86_lazy_plt_layout
{
- /* The first entry in an absolute lazy procedure linkage table looks
- like this. */
+ /* The first entry in a lazy procedure linkage table looks like this. */
const bfd_byte *plt0_entry;
- unsigned int plt0_entry_size; /* Size of PLT0 entry. */
+ unsigned int plt0_entry_size; /* Size of PLT0 entry. */
- /* Later entries in an absolute lazy procedure linkage table look
- like this. */
+ /* Later entries in a lazy procedure linkage table look like this. */
const bfd_byte *plt_entry;
- unsigned int plt_entry_size; /* Size of each PLT entry. */
+ unsigned int plt_entry_size; /* Size of each PLT entry. */
+
+ /* The TLSDESC entry in a lazy procedure linkage table looks like
+ this. This is for x86-64 only. */
+ const bfd_byte *plt_tlsdesc_entry;
+ unsigned int plt_tlsdesc_entry_size; /* Size of TLSDESC entry. */
+
+ /* Offsets into the TLSDESC entry that are to be replaced with
+ GOT+8 and GOT+TDG. These are for x86-64 only. */
+ unsigned int plt_tlsdesc_got1_offset;
+ unsigned int plt_tlsdesc_got2_offset;
+
+ /* Offset of the end of the PC-relative instructions containing
+ plt_tlsdesc_got1_offset and plt_tlsdesc_got2_offset. These
+ are for x86-64 only. */
+ unsigned int plt_tlsdesc_got1_insn_end;
+ unsigned int plt_tlsdesc_got2_insn_end;
/* Offsets into plt0_entry that are to be replaced with GOT[1] and
GOT[2]. */
struct elf_x86_non_lazy_plt_layout
{
- /* Entries in an absolute non-lazy procedure linkage table look like
- this. */
+ /* Entries in a non-lazy procedure linkage table look like this. */
const bfd_byte *plt_entry;
- /* Entries in a PIC non-lazy procedure linkage table look like this. */
+ /* Entries in a PIC non-lazy procedure linkage table look like this.
+ This is only used for i386 where absolute PLT and PIC PLT are
+ different. */
const bfd_byte *pic_plt_entry;
- unsigned int plt_entry_size; /* Size of each PLT entry. */
+ unsigned int plt_entry_size; /* Size of each PLT entry. */
/* Offsets into plt_entry that are to be replaced with... */
unsigned int plt_got_offset; /* ... address of this symbol in .got. */
struct elf_x86_plt_layout
{
- /* The first entry in a lazy procedure linkage table looks like this.
- This is only used for i386 where absolute PLT0 and PIC PLT0 are
- different. */
+ /* The first entry in a lazy procedure linkage table looks like this. */
const bfd_byte *plt0_entry;
/* Entries in a procedure linkage table look like this. */
const bfd_byte *plt_entry;
- unsigned int plt_entry_size; /* Size of each PLT entry. */
+ unsigned int plt_entry_size; /* Size of each PLT entry. */
/* 1 has PLT0. */
unsigned int has_plt0;
This is only used for x86-64. */
unsigned int plt_got_insn_size;
+ /* Alignment of the .iplt section. */
+ unsigned int iplt_alignment;
+
/* .eh_frame covering the .plt section. */
const bfd_byte *eh_frame_plt;
unsigned int eh_frame_plt_size;
#define GOT_TLS_IE_NEG 6
#define GOT_TLS_IE_BOTH 7
#define GOT_TLS_GDESC 8
+#define GOT_ABS 9
#define GOT_TLS_GD_BOTH_P(type) \
((type) == (GOT_TLS_GD | GOT_TLS_GDESC))
#define GOT_TLS_GD_P(type) \
#define elf_x86_hash_entry(ent) \
((struct elf_x86_link_hash_entry *)(ent))
+enum elf_x86_target_os
+{
+ is_normal,
+ is_solaris,
+ is_vxworks,
+ is_nacl
+};
+
/* x86 ELF linker hash table. */
struct elf_x86_link_hash_table
to read-only sections. */
bfd_boolean readonly_dynrelocs_against_ifunc;
- /* TRUE if this is a VxWorks x86 target. This is only used for
- i386. */
- bfd_boolean is_vxworks;
-
/* The (unloaded but important) .rel.plt.unloaded section on VxWorks.
This is used for i386 only. */
asection *srelplt2;
yet. This is only used for x86-64. */
bfd_vma tlsdesc_plt;
+ /* Value used to fill the unused bytes of the first PLT entry. This
+ is only used for i386. */
+ bfd_byte plt0_pad_byte;
+
+ /* TRUE if GOT is referenced. */
+ unsigned int got_referenced : 1;
+
+ /* TRUE if PLT is PC-relative. PLT in PDE and PC-relative PLT in PIE
+ can be used as function address.
+
+ NB: i386 has non-PIC PLT and PIC PLT. Only non-PIC PLT in PDE can
+ be used as function address. PIC PLT in PIE can't be used as
+ function address. */
+ unsigned int pcrel_plt : 1;
+
bfd_vma (*r_info) (bfd_vma, bfd_vma);
bfd_vma (*r_sym) (bfd_vma);
bfd_boolean (*is_reloc_section) (const char *);
enum elf_target_id target_id;
+ enum elf_x86_target_os target_os;
unsigned int sizeof_reloc;
unsigned int dt_reloc;
unsigned int dt_reloc_sz;
int dynamic_interpreter_size;
const char *dynamic_interpreter;
const char *tls_get_addr;
+
+ /* Options passed from the linker. */
+ struct elf_linker_x86_params *params;
};
+/* Architecture-specific backend data for x86. */
+
+struct elf_x86_backend_data
+{
+ /* Target system. */
+ enum elf_x86_target_os target_os;
+};
+
+#define get_elf_x86_backend_data(abfd) \
+ ((const struct elf_x86_backend_data *) \
+ get_elf_backend_data (abfd)->arch_data)
+
struct elf_x86_init_table
{
/* The lazy PLT layout. */
/* The non-lazy PLT layout for IBT. */
const struct elf_x86_non_lazy_plt_layout *non_lazy_ibt_plt;
- /* TRUE if this is a normal x86 target. */
- bfd_boolean normal_target;
-
- /* TRUE if this is a VxWorks x86 target. */
- bfd_boolean is_vxworks;
+ bfd_byte plt0_pad_byte;
bfd_vma (*r_info) (bfd_vma, bfd_vma);
bfd_vma (*r_sym) (bfd_vma);
long count;
};
+/* Set if a relocation is converted from a GOTPCREL relocation. */
+#define R_X86_64_converted_reloc_bit (1 << 7)
+
#define elf_x86_tdata(abfd) \
((struct elf_x86_obj_tdata *) (abfd)->tdata.any)
extern bfd_boolean _bfd_x86_elf_link_check_relocs
(bfd *, struct bfd_link_info *);
+extern bfd_boolean _bfd_elf_x86_valid_reloc_p
+ (asection *, struct bfd_link_info *, struct elf_x86_link_hash_table *,
+ const Elf_Internal_Rela *, struct elf_link_hash_entry *,
+ Elf_Internal_Sym *, Elf_Internal_Shdr *, bfd_boolean *);
+
extern bfd_boolean _bfd_x86_elf_size_dynamic_sections
(bfd *, struct bfd_link_info *);
(bfd *, unsigned int, bfd_byte *, unsigned int);
extern bfd_boolean _bfd_x86_elf_merge_gnu_properties
- (struct bfd_link_info *, bfd *, elf_property *, elf_property *);
+ (struct bfd_link_info *, bfd *, bfd *, elf_property *, elf_property *);
+
+extern void _bfd_x86_elf_link_fixup_gnu_properties
+ (struct bfd_link_info *, elf_property_list **);
extern bfd * _bfd_x86_elf_link_setup_gnu_properties
(struct bfd_link_info *, struct elf_x86_init_table *);
+extern void _bfd_x86_elf_link_fixup_ifunc_symbol
+ (struct bfd_link_info *, struct elf_x86_link_hash_table *,
+ struct elf_link_hash_entry *, Elf_Internal_Sym *sym);
+
#define bfd_elf64_mkobject \
_bfd_x86_elf_mkobject
#define bfd_elf32_mkobject \
#define elf_backend_gc_mark_hook \
_bfd_x86_elf_gc_mark_hook
#define elf_backend_omit_section_dynsym \
- ((bfd_boolean (*) (bfd *, struct bfd_link_info *, asection *)) bfd_true)
+ _bfd_elf_omit_section_dynsym_all
#define elf_backend_parse_gnu_properties \
_bfd_x86_elf_parse_gnu_properties
#define elf_backend_merge_gnu_properties \
_bfd_x86_elf_merge_gnu_properties
+#define elf_backend_fixup_gnu_properties \
+ _bfd_x86_elf_link_fixup_gnu_properties
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