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fd0de36e27
This patch adds support to BFD for elf64-bpf, in both little-endian and big-endian variants. bfd/ChangeLog: 2019-05-23 Jose E. Marchesi <jose.marchesi@oracle.com> * configure.ac: Add bpf_elf64_le_vec and bpf_elf64_be_vec. * configure: Regenerated. * Makefile.am (ALL_MACHINES): Add cpu-bpf.lo. (ALL_MACHINES_CFILES): Add cpu-bpf.c. (BFD64_BACKENDS): Add elf64-bpf.lo. (BFD64_BACKENDS_CFILES): Add elf64-bpf.c. * Makefile.in (SOURCE_HFILES): Regenerate. * config.bfd (targ_cpu): Handle bpf-*-* targets. * cpu-bpf.c: New file. * elf64-bpf.c: Likewise. * targets.c (_bfd_target_vector): Add bpf_elf64_be_vec and bpf_elf64_le_vec. * archures.c: Define architecture bfd_arch_bpf and machine bfd_arch_bpf. * reloc.c: Define BFD relocations used by the BPF target. * bfd-in2.h: Regenerated. * libbfd.h: Likewise.
464 lines
14 KiB
C
464 lines
14 KiB
C
/* Linux bpf specific support for 64-bit ELF
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Copyright (C) 2019 Free Software Foundation, Inc.
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Contributed by Oracle Inc.
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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; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "sysdep.h"
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#include "bfd.h"
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#include "libbfd.h"
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#include "elf-bfd.h"
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#include "elf/bpf.h"
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#include "libiberty.h"
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/* In case we're on a 32-bit machine, construct a 64-bit "-1" value. */
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#define MINUS_ONE (~ (bfd_vma) 0)
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#define BASEADDR(SEC) ((SEC)->output_section->vma + (SEC)->output_offset)
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/* Handler for PC-relative relocations, which must be handled in
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64-bit words. */
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static bfd_reloc_status_type
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bpf_elf_insn_disp_reloc (bfd *abfd,
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arelent *reloc_entry,
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asymbol *symbol,
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void *data,
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asection *input_section,
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bfd *output_bfd,
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char **error_message ATTRIBUTE_UNUSED)
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{
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bfd_signed_vma relocation;
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bfd_signed_vma addend;
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reloc_howto_type *howto = reloc_entry->howto;
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/* This part is from bfd_elf_generic_reloc. */
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if (output_bfd != NULL
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&& (symbol->flags & BSF_SECTION_SYM) == 0
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&& (! reloc_entry->howto->partial_inplace
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|| reloc_entry->addend == 0))
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{
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reloc_entry->address += input_section->output_offset;
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return bfd_reloc_ok;
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}
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/* This works because partial_inplace is FALSE. */
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if (output_bfd != NULL)
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return bfd_reloc_continue;
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if (reloc_entry->address > bfd_get_section_limit (abfd, input_section))
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return bfd_reloc_outofrange;
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relocation = (symbol->value
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+ symbol->section->output_section->vma
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+ symbol->section->output_offset);
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/* Make it PC relative. */
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relocation -= (input_section->output_section->vma
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+ input_section->output_offset);
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relocation -= reloc_entry->address;
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/* Make it 64-bit words. */
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relocation = relocation / 8;
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/* Get the addend from the instruction and apply it. */
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switch (howto->bitsize)
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{
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default:
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abort ();
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break;
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case 16:
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addend = bfd_get_16 (abfd, (bfd_byte *) data + reloc_entry->address + 2);
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break;
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case 32:
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addend = bfd_get_32 (abfd, (bfd_byte *) data + reloc_entry->address + 4);
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break;
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}
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if ((addend & (((~howto->src_mask) >> 1) & howto->src_mask)) != 0)
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addend -= (((~howto->src_mask) >> 1) & howto->src_mask) << 1;
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relocation += addend;
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/* Write out the relocated value. */
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switch (howto->bitsize)
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{
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default:
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abort ();
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break;
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case 16:
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bfd_put_16 (abfd, relocation, (bfd_byte *) data + reloc_entry->address + 2);
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break;
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case 32:
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bfd_put_32 (abfd, relocation, (bfd_byte *) data + reloc_entry->address + 4);
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break;
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}
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/* Check for overflow. */
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if (howto->complain_on_overflow == complain_overflow_signed)
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{
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bfd_signed_vma reloc_signed_max = (1 << (howto->bitsize - 1)) - 1;
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bfd_signed_vma reloc_signed_min = ~reloc_signed_max;
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if (relocation > reloc_signed_max || relocation < reloc_signed_min)
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return bfd_reloc_overflow;
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}
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else
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abort();
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return bfd_reloc_ok;
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}
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/* Relocation tables. */
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static reloc_howto_type bpf_elf_howto_table [] =
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{
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/* This reloc does nothing. */
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HOWTO (R_BPF_NONE, /* type */
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0, /* rightshift */
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3, /* size (0 = byte, 1 = short, 2 = long) */
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0, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_dont, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_NONE", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0, /* dst_mask */
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FALSE), /* pcrel_offset */
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/* 64-immediate in LDDW instruction. */
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HOWTO (R_BPF_INSN_64, /* type */
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0, /* rightshift */
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4, /* size (0 = byte, 1 = short, 2 = long) */
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64, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_INSN_64", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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MINUS_ONE, /* dst_mask */
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TRUE), /* pcrel_offset */
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/* 32-immediate in LDDW instruction. */
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HOWTO (R_BPF_INSN_32, /* type */
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0, /* rightshift */
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2, /* size (0 = byte, 1 = short, 2 = long) */
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32, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_INSN_32", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0xffffffff, /* dst_mask */
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TRUE), /* pcrel_offset */
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/* 16-bit offsets in instructions. */
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HOWTO (R_BPF_INSN_16, /* type */
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0, /* rightshift */
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1, /* size (0 = byte, 1 = short, 2 = long) */
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16, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_INSN_16", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0x0000ffff, /* dst_mask */
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TRUE), /* pcrel_offset */
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/* 16-bit PC-relative address in jump instructions. */
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HOWTO (R_BPF_INSN_DISP16, /* type */
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0, /* rightshift */
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1, /* size (0 = byte, 1 = short, 2 = long) */
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16, /* bitsize */
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TRUE, /* pc_relative */
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32, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bpf_elf_insn_disp_reloc, /* special_function */
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"R_BPF_INSN_DISP16", /* name */
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FALSE, /* partial_inplace */
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0xffff, /* src_mask */
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0xffff, /* dst_mask */
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TRUE), /* pcrel_offset */
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HOWTO (R_BPF_DATA_8_PCREL,
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0, /* rightshift */
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0, /* size (0 = byte, 1 = short, 2 = long) */
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8, /* bitsize */
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TRUE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_8_PCREL", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0xff, /* dst_mask */
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TRUE), /* pcrel_offset */
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HOWTO (R_BPF_DATA_16_PCREL,
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0, /* rightshift */
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1, /* size (0 = byte, 1 = short, 2 = long) */
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16, /* bitsize */
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TRUE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_16_PCREL", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0xffff, /* dst_mask */
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TRUE), /* pcrel_offset */
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HOWTO (R_BPF_DATA_32_PCREL,
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0, /* rightshift */
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2, /* size (0 = byte, 1 = short, 2 = long) */
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32, /* bitsize */
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TRUE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_32_PCREL", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0xffffffff, /* dst_mask */
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TRUE), /* pcrel_offset */
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HOWTO (R_BPF_DATA_8,
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0, /* rightshift */
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0, /* size (0 = byte, 1 = short, 2 = long) */
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8, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_unsigned, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_DATA_8", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0xff, /* dst_mask */
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FALSE), /* pcrel_offset */
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HOWTO (R_BPF_DATA_16,
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0, /* rightshift */
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1, /* size (0 = byte, 1 = short, 2 = long) */
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16, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_unsigned, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_DATA_16", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0xffff, /* dst_mask */
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FALSE), /* pcrel_offset */
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/* 32-bit PC-relative address in call instructions. */
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HOWTO (R_BPF_INSN_DISP32, /* type */
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0, /* rightshift */
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2, /* size (0 = byte, 1 = short, 2 = long) */
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32, /* bitsize */
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TRUE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bpf_elf_insn_disp_reloc, /* special_function */
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"R_BPF_INSN_DISP32", /* name */
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FALSE, /* partial_inplace */
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0xffffffff, /* src_mask */
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0xffffffff, /* dst_mask */
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TRUE), /* pcrel_offset */
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/* 32-bit data. */
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HOWTO (R_BPF_DATA_32, /* type */
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0, /* rightshift */
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2, /* size (0 = byte, 1 = short, 2 = long) */
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32, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_bitfield, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_DATA_32", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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0xffffffff, /* dst_mask */
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TRUE), /* pcrel_offset */
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/* 64-bit data. */
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HOWTO (R_BPF_DATA_64, /* type */
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0, /* rightshift */
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4, /* size (0 = byte, 1 = short, 2 = long) */
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64, /* bitsize */
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FALSE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_bitfield, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_DATA_64", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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MINUS_ONE, /* dst_mask */
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TRUE), /* pcrel_offset */
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HOWTO (R_BPF_DATA_64_PCREL,
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0, /* rightshift */
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4, /* size (0 = byte, 1 = short, 2 = long) */
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64, /* bitsize */
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TRUE, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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bfd_elf_generic_reloc, /* special_function */
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"R_BPF_64_PCREL", /* name */
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FALSE, /* partial_inplace */
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0, /* src_mask */
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MINUS_ONE, /* dst_mask */
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TRUE), /* pcrel_offset */
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};
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#undef AHOW
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/* Map BFD reloc types to bpf ELF reloc types. */
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static reloc_howto_type *
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bpf_reloc_type_lookup (bfd * abfd ATTRIBUTE_UNUSED,
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bfd_reloc_code_real_type code)
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{
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/* Note that the bpf_elf_howto_table is indxed by the R_
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constants. Thus, the order that the howto records appear in the
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table *must* match the order of the relocation types defined in
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include/elf/bpf.h. */
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switch (code)
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{
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case BFD_RELOC_NONE:
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return &bpf_elf_howto_table[ (int) R_BPF_NONE];
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case BFD_RELOC_8_PCREL:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_8_PCREL];
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case BFD_RELOC_16_PCREL:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_16_PCREL];
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case BFD_RELOC_32_PCREL:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_32_PCREL];
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case BFD_RELOC_64_PCREL:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_64_PCREL];
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case BFD_RELOC_8:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_8];
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case BFD_RELOC_16:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_16];
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case BFD_RELOC_32:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_32];
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case BFD_RELOC_64:
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return &bpf_elf_howto_table[ (int) R_BPF_DATA_64];
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case BFD_RELOC_BPF_64:
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return &bpf_elf_howto_table[ (int) R_BPF_INSN_64];
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case BFD_RELOC_BPF_32:
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return &bpf_elf_howto_table[ (int) R_BPF_INSN_32];
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case BFD_RELOC_BPF_16:
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return &bpf_elf_howto_table[ (int) R_BPF_INSN_16];
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case BFD_RELOC_BPF_DISP16:
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return &bpf_elf_howto_table[ (int) R_BPF_INSN_DISP16];
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case BFD_RELOC_BPF_DISP32:
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return &bpf_elf_howto_table[ (int) R_BPF_INSN_DISP32];
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default:
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/* Pacify gcc -Wall. */
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return NULL;
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}
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return NULL;
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}
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/* Map BFD reloc names to bpf ELF reloc names. */
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static reloc_howto_type *
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bpf_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED, const char *r_name)
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{
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE (bpf_elf_howto_table); i++)
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if (bpf_elf_howto_table[i].name != NULL
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&& strcasecmp (bpf_elf_howto_table[i].name, r_name) == 0)
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return &bpf_elf_howto_table[i];
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return NULL;
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}
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/* Set the howto pointer for a bpf reloc. */
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static bfd_boolean
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bpf_info_to_howto (bfd *abfd, arelent *bfd_reloc,
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Elf_Internal_Rela *elf_reloc)
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{
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unsigned int r_type;
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r_type = ELF64_R_TYPE (elf_reloc->r_info);
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if (r_type >= (unsigned int) R_BPF_max)
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{
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/* xgettext:c-format */
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_bfd_error_handler (_("%pB: unsupported relocation type %#x"),
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abfd, r_type);
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bfd_set_error (bfd_error_bad_value);
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return FALSE;
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}
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bfd_reloc->howto = &bpf_elf_howto_table [r_type];
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return TRUE;
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}
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/* Merge backend specific data from an object file to the output
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object file when linking. */
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static bfd_boolean
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elf64_bpf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
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{
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/* Check if we have the same endianness. */
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if (! _bfd_generic_verify_endian_match (ibfd, info))
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return FALSE;
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return TRUE;
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}
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/* The macros below configure the architecture. */
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#define TARGET_LITTLE_SYM bpf_elf64_le_vec
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#define TARGET_LITTLE_NAME "elf64-bpfle"
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#define TARGET_BIG_SYM bpf_elf64_be_vec
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#define TARGET_BIG_NAME "elf64-bpfbe"
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#define ELF_ARCH bfd_arch_bpf
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#define ELF_MACHINE_CODE EM_BPF
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#define ELF_MAXPAGESIZE 0x100000
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#define elf_info_to_howto_rel bpf_info_to_howto
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#define elf_info_to_howto bpf_info_to_howto
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#define elf_backend_may_use_rel_p 1
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#define elf_backend_may_use_rela_p 0
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#define elf_backend_default_use_rela_p 0
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#define elf_backend_can_gc_sections 0
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#define elf_symbol_leading_char '_'
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#define bfd_elf64_bfd_reloc_type_lookup bpf_reloc_type_lookup
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#define bfd_elf64_bfd_reloc_name_lookup bpf_reloc_name_lookup
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#define bfd_elf64_bfd_merge_private_bfd_data elf64_bpf_merge_private_bfd_data
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#include "elf64-target.h"
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