/* Linux bpf specific support for 64-bit ELF
- Copyright (C) 2019-2020 Free Software Foundation, Inc.
+ Copyright (C) 2019-2023 Free Software Foundation, Inc.
Contributed by Oracle Inc.
This file is part of BFD, the Binary File Descriptor library.
#define BASEADDR(SEC) ((SEC)->output_section->vma + (SEC)->output_offset)
+static bfd_reloc_status_type bpf_elf_generic_reloc
+ (bfd *, arelent *, asymbol *, void *, asection *, bfd *, char **);
+
+#undef BPF_HOWTO
+#define BPF_HOWTO(type, right, size, bits, pcrel, left, ovf, func, name, \
+ inplace, src_mask, dst_mask, pcrel_off) \
+ type##_IDX,
+enum bpf_reloc_index {
+ R_BPF_INVALID_IDX = -1,
+#include "bpf-reloc.def"
+ R_BPF_SIZE
+};
+#undef BPF_HOWTO
+
/* Relocation tables. */
+#define BPF_HOWTO(...) HOWTO(__VA_ARGS__),
static reloc_howto_type bpf_elf_howto_table [] =
{
- /* This reloc does nothing. */
- HOWTO (R_BPF_NONE, /* type */
- 0, /* rightshift */
- 3, /* size (0 = byte, 1 = short, 2 = long) */
- 0, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_dont, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_NONE", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0, /* dst_mask */
- FALSE), /* pcrel_offset */
-
- /* 64-immediate in LDDW instruction. */
- HOWTO (R_BPF_INSN_64, /* type */
- 0, /* rightshift */
- 4, /* size (0 = byte, 1 = short, 2 = long) */
- 64, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_INSN_64", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- MINUS_ONE, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- /* 32-immediate in LDDW instruction. */
- HOWTO (R_BPF_INSN_32, /* type */
- 0, /* rightshift */
- 2, /* size (0 = byte, 1 = short, 2 = long) */
- 32, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_INSN_32", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0xffffffff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- /* 16-bit offsets in instructions. */
- HOWTO (R_BPF_INSN_16, /* type */
- 0, /* rightshift */
- 1, /* size (0 = byte, 1 = short, 2 = long) */
- 16, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_INSN_16", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0x0000ffff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- /* 16-bit PC-relative address in jump instructions. */
- HOWTO (R_BPF_INSN_DISP16, /* type */
- 0, /* rightshift */
- 1, /* size (0 = byte, 1 = short, 2 = long) */
- 16, /* bitsize */
- TRUE, /* pc_relative */
- 32, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_INSN_DISP16", /* name */
- FALSE, /* partial_inplace */
- 0xffff, /* src_mask */
- 0xffff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- HOWTO (R_BPF_DATA_8_PCREL,
- 0, /* rightshift */
- 0, /* size (0 = byte, 1 = short, 2 = long) */
- 8, /* bitsize */
- TRUE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_8_PCREL", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0xff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- HOWTO (R_BPF_DATA_16_PCREL,
- 0, /* rightshift */
- 1, /* size (0 = byte, 1 = short, 2 = long) */
- 16, /* bitsize */
- TRUE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_16_PCREL", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0xffff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- HOWTO (R_BPF_DATA_32_PCREL,
- 0, /* rightshift */
- 2, /* size (0 = byte, 1 = short, 2 = long) */
- 32, /* bitsize */
- TRUE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_32_PCREL", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0xffffffff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- HOWTO (R_BPF_DATA_8,
- 0, /* rightshift */
- 0, /* size (0 = byte, 1 = short, 2 = long) */
- 8, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_unsigned, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_DATA_8", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0xff, /* dst_mask */
- FALSE), /* pcrel_offset */
-
- HOWTO (R_BPF_DATA_16,
- 0, /* rightshift */
- 1, /* size (0 = byte, 1 = short, 2 = long) */
- 16, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_unsigned, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_DATA_16", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0xffff, /* dst_mask */
- FALSE), /* pcrel_offset */
-
- /* 32-bit PC-relative address in call instructions. */
- HOWTO (R_BPF_INSN_DISP32, /* type */
- 0, /* rightshift */
- 2, /* size (0 = byte, 1 = short, 2 = long) */
- 32, /* bitsize */
- TRUE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_INSN_DISP32", /* name */
- FALSE, /* partial_inplace */
- 0xffffffff, /* src_mask */
- 0xffffffff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- /* 32-bit data. */
- HOWTO (R_BPF_DATA_32, /* type */
- 0, /* rightshift */
- 2, /* size (0 = byte, 1 = short, 2 = long) */
- 32, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_bitfield, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_DATA_32", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- 0xffffffff, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- /* 64-bit data. */
- HOWTO (R_BPF_DATA_64, /* type */
- 0, /* rightshift */
- 4, /* size (0 = byte, 1 = short, 2 = long) */
- 64, /* bitsize */
- FALSE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_bitfield, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_DATA_64", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- MINUS_ONE, /* dst_mask */
- TRUE), /* pcrel_offset */
-
- HOWTO (R_BPF_DATA_64_PCREL,
- 0, /* rightshift */
- 4, /* size (0 = byte, 1 = short, 2 = long) */
- 64, /* bitsize */
- TRUE, /* pc_relative */
- 0, /* bitpos */
- complain_overflow_signed, /* complain_on_overflow */
- bfd_elf_generic_reloc, /* special_function */
- "R_BPF_64_PCREL", /* name */
- FALSE, /* partial_inplace */
- 0, /* src_mask */
- MINUS_ONE, /* dst_mask */
- TRUE), /* pcrel_offset */
+ #include "bpf-reloc.def"
};
#undef AHOW
+#undef BPF_HOWTO
+
+#define BPF_HOWTO(type, right, size, bits, pcrel, left, ovf, func, name, \
+ inplace, src_mask, dst_mask, pcrel_off) \
+ case type: { return type##_IDX; }
+static enum bpf_reloc_index
+bpf_index_for_rtype(unsigned int r_type)
+{
+ switch(r_type) {
+#include "bpf-reloc.def"
+ default:
+ /* Unreachable code. */
+ BFD_ASSERT(0);
+ return -1;
+ };
+}
/* Map BFD reloc types to bpf ELF reloc types. */
bpf_reloc_type_lookup (bfd * abfd ATTRIBUTE_UNUSED,
bfd_reloc_code_real_type code)
{
- /* Note that the bpf_elf_howto_table is indexed by the R_ constants.
- Thus, the order that the howto records appear in the table *must*
- match the order of the relocation types defined in
- include/elf/bpf.h. */
-
switch (code)
{
case BFD_RELOC_NONE:
- return &bpf_elf_howto_table[ (int) R_BPF_NONE];
-
- case BFD_RELOC_8_PCREL:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_8_PCREL];
- case BFD_RELOC_16_PCREL:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_16_PCREL];
- case BFD_RELOC_32_PCREL:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_32_PCREL];
- case BFD_RELOC_64_PCREL:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_64_PCREL];
-
- case BFD_RELOC_8:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_8];
- case BFD_RELOC_16:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_16];
+ return &bpf_elf_howto_table[ (int) R_BPF_NONE_IDX];
+
case BFD_RELOC_32:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_32];
+ return &bpf_elf_howto_table[ (int) R_BPF_64_ABS32_IDX];
case BFD_RELOC_64:
- return &bpf_elf_howto_table[ (int) R_BPF_DATA_64];
+ return &bpf_elf_howto_table[ (int) R_BPF_64_ABS64_IDX];
case BFD_RELOC_BPF_64:
- return &bpf_elf_howto_table[ (int) R_BPF_INSN_64];
- case BFD_RELOC_BPF_32:
- return &bpf_elf_howto_table[ (int) R_BPF_INSN_32];
- case BFD_RELOC_BPF_16:
- return &bpf_elf_howto_table[ (int) R_BPF_INSN_16];
- case BFD_RELOC_BPF_DISP16:
- return &bpf_elf_howto_table[ (int) R_BPF_INSN_DISP16];
+ return &bpf_elf_howto_table[ (int) R_BPF_64_64_IDX];
case BFD_RELOC_BPF_DISP32:
- return &bpf_elf_howto_table[ (int) R_BPF_INSN_DISP32];
+ case BFD_RELOC_BPF_DISPCALL32:
+ return &bpf_elf_howto_table[ (int) R_BPF_64_32_IDX];
+ case BFD_RELOC_BPF_DISP16:
+ return &bpf_elf_howto_table[ (int) R_BPF_GNU_64_16_IDX];
default:
/* Pacify gcc -Wall. */
{
unsigned int i;
- for (i = 0; i < ARRAY_SIZE (bpf_elf_howto_table); i++)
+ for (i = 0; i < R_BPF_SIZE; i++)
if (bpf_elf_howto_table[i].name != NULL
&& strcasecmp (bpf_elf_howto_table[i].name, r_name) == 0)
return &bpf_elf_howto_table[i];
/* Set the howto pointer for a bpf reloc. */
-static bfd_boolean
+static bool
bpf_info_to_howto (bfd *abfd, arelent *bfd_reloc,
Elf_Internal_Rela *elf_reloc)
{
unsigned int r_type;
-
+ unsigned int i;
r_type = ELF64_R_TYPE (elf_reloc->r_info);
- if (r_type >= (unsigned int) R_BPF_max)
+
+ i = bpf_index_for_rtype(r_type);
+ if (i == (unsigned int) -1)
{
/* xgettext:c-format */
_bfd_error_handler (_("%pB: unsupported relocation type %#x"),
abfd, r_type);
bfd_set_error (bfd_error_bad_value);
- return FALSE;
+ return false;
}
- bfd_reloc->howto = &bpf_elf_howto_table [r_type];
- return TRUE;
+ bfd_reloc->howto = &bpf_elf_howto_table [i];
+ return true;
}
/* Relocate an eBPF ELF section.
#define sec_addr(sec) ((sec)->output_section->vma + (sec)->output_offset)
-static bfd_boolean
+static int
bpf_elf_relocate_section (bfd *output_bfd ATTRIBUTE_UNUSED,
struct bfd_link_info *info,
bfd *input_bfd,
for (rel = relocs; rel < relend; rel ++)
{
reloc_howto_type * howto;
+ unsigned int howto_index;
unsigned long r_symndx;
Elf_Internal_Sym * sym;
asection * sec;
bfd_reloc_status_type r;
const char * name = NULL;
int r_type ATTRIBUTE_UNUSED;
+ bfd_signed_vma addend;
+ bfd_byte * where;
r_type = ELF64_R_TYPE (rel->r_info);
r_symndx = ELF64_R_SYM (rel->r_info);
- howto = bpf_elf_howto_table + ELF64_R_TYPE (rel->r_info);
+
+ howto_index = bpf_index_for_rtype (ELF64_R_TYPE (rel->r_info));
+ howto = &bpf_elf_howto_table[howto_index];
h = NULL;
sym = NULL;
sec = NULL;
+ where = contents + rel->r_offset;
if (r_symndx < symtab_hdr->sh_info)
{
}
else
{
- bfd_boolean warned ATTRIBUTE_UNUSED;
- bfd_boolean unresolved_reloc ATTRIBUTE_UNUSED;
- bfd_boolean ignored ATTRIBUTE_UNUSED;
+ bool warned ATTRIBUTE_UNUSED;
+ bool unresolved_reloc ATTRIBUTE_UNUSED;
+ bool ignored ATTRIBUTE_UNUSED;
RELOC_FOR_GLOBAL_SYMBOL (info, input_bfd, input_section, rel,
r_symndx, symtab_hdr, sym_hashes,
switch (howto->type)
{
- case R_BPF_INSN_DISP16:
- case R_BPF_INSN_DISP32:
+ case R_BPF_64_32:
{
- bfd_signed_vma addend;
-
/* Make the relocation PC-relative, and change its unit to
- 64-bit words. */
- relocation -= sec_addr (input_section) + rel->r_offset;
- /* Make it 64-bit words. */
- relocation = relocation / 8;
+ 64-bit words. Note we need *signed* arithmetic
+ here. */
+ relocation = ((bfd_signed_vma) relocation
+ - (sec_addr (input_section) + rel->r_offset));
+ relocation = (bfd_signed_vma) relocation / 8;
/* Get the addend from the instruction and apply it. */
addend = bfd_get (howto->bitsize, input_bfd,
r = bfd_reloc_ok;
break;
}
+ case R_BPF_64_ABS64:
+ case R_BPF_64_ABS32:
+ {
+ addend = bfd_get (howto->bitsize, input_bfd, where);
+ relocation += addend;
+ bfd_put (howto->bitsize, input_bfd, relocation, where);
+
+ r = bfd_reloc_ok;
+ break;
+ }
+ case R_BPF_64_64:
+ {
+ /*
+ LDDW instructions are 128 bits long, with a 64-bit immediate.
+ The lower 32 bits of the immediate are in the same position
+ as the imm32 field of other instructions.
+ The upper 32 bits of the immediate are stored at the end of
+ the instruction.
+ */
+
+
+ /* Get the addend. The upper and lower 32 bits are split.
+ 'where' is the beginning of the 16-byte instruction. */
+ addend = bfd_get_32 (input_bfd, where + 4);
+ addend |= (bfd_get_32 (input_bfd, where + 12) << 32);
+
+ relocation += addend;
+
+ bfd_put_32 (input_bfd, (relocation & 0xFFFFFFFF), where + 4);
+ bfd_put_32 (input_bfd, (relocation >> 32), where + 12);
+ r = bfd_reloc_ok;
+ break;
+ }
default:
- r = _bfd_final_link_relocate (howto, input_bfd, input_section,
- contents, rel->r_offset, relocation,
- rel->r_addend);
+ r = bfd_reloc_notsupported;
}
+ if (r == bfd_reloc_ok)
+ r = bfd_check_overflow (howto->complain_on_overflow,
+ howto->bitsize,
+ howto->rightshift,
+ 64, relocation);
+
if (r != bfd_reloc_ok)
{
const char * msg = NULL;
case bfd_reloc_undefined:
(*info->callbacks->undefined_symbol)
- (info, name, input_bfd, input_section, rel->r_offset, TRUE);
+ (info, name, input_bfd, input_section, rel->r_offset, true);
break;
case bfd_reloc_outofrange:
}
}
- return TRUE;
+ return true;
}
/* Merge backend specific data from an object file to the output
object file when linking. */
-static bfd_boolean
+static bool
elf64_bpf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
{
/* Check if we have the same endianness. */
if (! _bfd_generic_verify_endian_match (ibfd, info))
- return FALSE;
+ return false;
- return TRUE;
+ return true;
}
+/* A generic howto special function for installing BPF relocations.
+ This function will be called by the assembler (via bfd_install_relocation),
+ and by various get_relocated_section_contents functions.
+ At link time, bpf_elf_relocate_section will resolve the final relocations.
+
+ BPF instructions are always big endian, and this approach avoids problems in
+ bfd_install_relocation. */
+
+static bfd_reloc_status_type
+bpf_elf_generic_reloc (bfd *abfd, arelent *reloc_entry, asymbol *symbol,
+ void *data, asection *input_section,
+ bfd *output_bfd ATTRIBUTE_UNUSED,
+ char **error_message ATTRIBUTE_UNUSED)
+{
+
+ bfd_signed_vma relocation;
+ bfd_reloc_status_type status;
+ bfd_byte *where;
+
+ /* Sanity check that the address is in range. */
+ bfd_size_type end = bfd_get_section_limit_octets (abfd, input_section);
+ bfd_size_type reloc_size;
+ if (reloc_entry->howto->type == R_BPF_64_64)
+ reloc_size = 16;
+ else
+ reloc_size = (reloc_entry->howto->bitsize
+ + reloc_entry->howto->bitpos) / 8;
+
+ if (reloc_entry->address > end
+ || end - reloc_entry->address < reloc_size)
+ return bfd_reloc_outofrange;
+
+ /* Get the symbol value. */
+ if (bfd_is_com_section (symbol->section))
+ relocation = 0;
+ else
+ relocation = symbol->value;
+
+ if (symbol->flags & BSF_SECTION_SYM)
+ /* Relocation against a section symbol: add in the section base address. */
+ relocation += BASEADDR (symbol->section);
+
+ relocation += reloc_entry->addend;
+
+ where = (bfd_byte *) data + reloc_entry->address;
+
+ status = bfd_check_overflow (reloc_entry->howto->complain_on_overflow,
+ reloc_entry->howto->bitsize,
+ reloc_entry->howto->rightshift, 64, relocation);
+
+ if (status != bfd_reloc_ok)
+ return status;
+
+ /* Now finally install the relocation. */
+ if (reloc_entry->howto->type == R_BPF_64_64)
+ {
+ /* lddw is a 128-bit (!) instruction that allows loading a 64-bit
+ immediate into a register. the immediate is split in half, with the
+ lower 32 bits in the same position as the imm32 field of other
+ instructions, and the upper 32 bits placed at the very end of the
+ instruction. that is, there are 32 unused bits between them. */
+
+ bfd_put_32 (abfd, (relocation & 0xFFFFFFFF), where + 4);
+ bfd_put_32 (abfd, (relocation >> 32), where + 12);
+ }
+ else
+ {
+ /* For other kinds of relocations, the relocated value simply goes
+ BITPOS bits from the start of the entry. This is always a multiple
+ of 8, i.e. whole bytes. */
+ bfd_put (reloc_entry->howto->bitsize, abfd, relocation,
+ where + reloc_entry->howto->bitpos / 8);
+ }
+
+ reloc_entry->addend = relocation;
+ reloc_entry->address += input_section->output_offset;
+
+ return bfd_reloc_ok;
+}
+
+
/* The macros below configure the architecture. */
#define TARGET_LITTLE_SYM bpf_elf64_le_vec
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