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BPF relocations review / refactoring

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- Removed not needed relocations.
- Renamed relocations to match llvm and linux kernel.

Relocation changes:
  R_BPF_INSN_64 	=> R_BPF_64_64
  R_BPF_INSN_DISP32 	=> R_BPF_64_32
  R_BPF_DATA_32 	=> R_BPF_64_ABS32
  R_BPF_DATA_64 	=> R_BPF_64_ABS64

ChangeLog:

  * bfd/bpf-reloc.def: Created file with BPF_HOWTO macro entries.
  * bfd/reloc.c: Removed non needed relocations.
  * bfd/bfd-in2.h: regenerated.
  * bfd/libbfd.h: regenerated.
  * bfd/elf64-bpf.c: Changed relocations.
  * include/elf/bpf.h: Adapted relocation values/names.
  * gas/config/tc-bpf.c: Changed relocation mapping.
This commit is contained in:
Cupertino Miranda
2023-03-16 08:39:52 +00:00
parent 6752dd75f7
commit 5e4c7a839d
7 changed files with 128 additions and 299 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
bfd/bfd-in2.h
View File

@@ -6079,9 +6079,6 @@ assembler and not (currently) written to any object files. */
/* Linux eBPF relocations. */
BFD_RELOC_BPF_64,
BFD_RELOC_BPF_32,
BFD_RELOC_BPF_16,
BFD_RELOC_BPF_DISP16,
BFD_RELOC_BPF_DISP32,
/* Adapteva EPIPHANY - 8 bit signed pc-relative displacement */

74
bfd/bpf-reloc.def Normal file
View File

@@ -0,0 +1,74 @@
/* This reloc does nothing. */
BPF_HOWTO (R_BPF_NONE, /* type */
0, /* rightshift */
0, /* size */
0, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_dont, /* complain_on_overflow */
bpf_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. */
BPF_HOWTO (R_BPF_64_64, /* type */
0, /* rightshift */
8, /* size */
64, /* bitsize */
false, /* pc_relative */
32, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_64_64", /* name */
true, /* partial_inplace */
MINUS_ONE, /* src_mask */
MINUS_ONE, /* dst_mask */
true) /* pcrel_offset */
/* 32-bit data. */
BPF_HOWTO (R_BPF_64_ABS32, /* type */
0, /* rightshift */
4, /* size */
32, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_bitfield, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_64_ABS32", /* name */
false, /* partial_inplace */
0xffffffff, /* src_mask */
0xffffffff, /* dst_mask */
true) /* pcrel_offset */
/* 64-bit data. */
BPF_HOWTO (R_BPF_64_ABS64, /* type */
0, /* rightshift */
8, /* size */
64, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_bitfield, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_64_ABS64", /* name */
false, /* partial_inplace */
0, /* src_mask */
MINUS_ONE, /* dst_mask */
true) /* pcrel_offset */
/* 32-bit PC-relative address in call instructions. */
BPF_HOWTO (R_BPF_64_32, /* type */
0, /* rightshift */
4, /* size */
32, /* bitsize */
true, /* pc_relative */
32, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_64_32", /* name */
true, /* partial_inplace */
0xffffffff, /* src_mask */
0xffffffff, /* dst_mask */
true) /* pcrel_offset */

312
bfd/elf64-bpf.c
View File

@@ -34,214 +34,40 @@
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 */
0, /* size */
0, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_dont, /* complain_on_overflow */
bpf_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 */
8, /* size */
64, /* bitsize */
false, /* pc_relative */
32, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_INSN_64", /* name */
true, /* partial_inplace */
MINUS_ONE, /* src_mask */
MINUS_ONE, /* dst_mask */
true), /* pcrel_offset */
/* 32-immediate in many instructions. */
HOWTO (R_BPF_INSN_32, /* type */
0, /* rightshift */
4, /* size */
32, /* bitsize */
false, /* pc_relative */
32, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_INSN_32", /* name */
true, /* partial_inplace */
0xffffffff, /* src_mask */
0xffffffff, /* dst_mask */
true), /* pcrel_offset */
/* 16-bit offsets in instructions. */
HOWTO (R_BPF_INSN_16, /* type */
0, /* rightshift */
2, /* size */
16, /* bitsize */
false, /* pc_relative */
16, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_INSN_16", /* name */
true, /* partial_inplace */
0x0000ffff, /* src_mask */
0x0000ffff, /* dst_mask */
true), /* pcrel_offset */
/* 16-bit PC-relative address in jump instructions. */
HOWTO (R_BPF_INSN_DISP16, /* type */
0, /* rightshift */
2, /* size */
16, /* bitsize */
true, /* pc_relative */
16, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_INSN_DISP16", /* name */
true, /* partial_inplace */
0xffff, /* src_mask */
0xffff, /* dst_mask */
true), /* pcrel_offset */
HOWTO (R_BPF_DATA_8_PCREL,
0, /* rightshift */
1, /* size */
8, /* bitsize */
true, /* pc_relative */
0, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_8_PCREL", /* name */
true, /* partial_inplace */
0xff, /* src_mask */
0xff, /* dst_mask */
true), /* pcrel_offset */
HOWTO (R_BPF_DATA_16_PCREL,
0, /* rightshift */
2, /* size */
16, /* bitsize */
true, /* pc_relative */
0, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_16_PCREL", /* name */
false, /* partial_inplace */
0xffff, /* src_mask */
0xffff, /* dst_mask */
true), /* pcrel_offset */
HOWTO (R_BPF_DATA_32_PCREL,
0, /* rightshift */
4, /* size */
32, /* bitsize */
true, /* pc_relative */
0, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_32_PCREL", /* name */
false, /* partial_inplace */
0xffffffff, /* src_mask */
0xffffffff, /* dst_mask */
true), /* pcrel_offset */
HOWTO (R_BPF_DATA_8,
0, /* rightshift */
1, /* size */
8, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_unsigned, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_DATA_8", /* name */
true, /* partial_inplace */
0xff, /* src_mask */
0xff, /* dst_mask */
false), /* pcrel_offset */
HOWTO (R_BPF_DATA_16,
0, /* rightshift */
2, /* size */
16, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_unsigned, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_DATA_16", /* name */
false, /* partial_inplace */
0xffff, /* src_mask */
0xffff, /* dst_mask */
false), /* pcrel_offset */
/* 32-bit PC-relative address in call instructions. */
HOWTO (R_BPF_INSN_DISP32, /* type */
0, /* rightshift */
4, /* size */
32, /* bitsize */
true, /* pc_relative */
32, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_INSN_DISP32", /* name */
true, /* partial_inplace */
0xffffffff, /* src_mask */
0xffffffff, /* dst_mask */
true), /* pcrel_offset */
/* 32-bit data. */
HOWTO (R_BPF_DATA_32, /* type */
0, /* rightshift */
4, /* size */
32, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_bitfield, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_DATA_32", /* name */
false, /* partial_inplace */
0xffffffff, /* src_mask */
0xffffffff, /* dst_mask */
true), /* pcrel_offset */
/* 64-bit data. */
HOWTO (R_BPF_DATA_64, /* type */
0, /* rightshift */
8, /* size */
64, /* bitsize */
false, /* pc_relative */
0, /* bitpos */
complain_overflow_bitfield, /* complain_on_overflow */
bpf_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 */
8, /* size */
64, /* bitsize */
true, /* pc_relative */
0, /* bitpos */
complain_overflow_signed, /* complain_on_overflow */
bpf_elf_generic_reloc, /* special_function */
"R_BPF_64_PCREL", /* name */
false, /* partial_inplace */
MINUS_ONE, /* 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. */
@@ -249,44 +75,20 @@ static reloc_howto_type *
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];
return &bpf_elf_howto_table[ (int) R_BPF_NONE_IDX];
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];
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];
return &bpf_elf_howto_table[ (int) R_BPF_64_32_IDX];
default:
/* Pacify gcc -Wall. */
@@ -302,7 +104,7 @@ bpf_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED, const char *r_name)
{
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];
@@ -317,9 +119,11 @@ 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"),
@@ -328,7 +132,7 @@ bpf_info_to_howto (bfd *abfd, arelent *bfd_reloc,
return false;
}
bfd_reloc->howto = &bpf_elf_howto_table [r_type];
bfd_reloc->howto = &bpf_elf_howto_table [i];
return true;
}
@@ -438,8 +242,7 @@ bpf_elf_relocate_section (bfd *output_bfd ATTRIBUTE_UNUSED,
switch (howto->type)
{
case R_BPF_INSN_DISP16:
case R_BPF_INSN_DISP32:
case R_BPF_64_32:
{
/* Make the relocation PC-relative, and change its unit to
64-bit words. Note we need *signed* arithmetic
@@ -465,10 +268,8 @@ bpf_elf_relocate_section (bfd *output_bfd ATTRIBUTE_UNUSED,
r = bfd_reloc_ok;
break;
}
case R_BPF_DATA_8:
case R_BPF_DATA_16:
case R_BPF_DATA_32:
case R_BPF_DATA_64:
case R_BPF_64_ABS64:
case R_BPF_64_ABS32:
{
addend = bfd_get (howto->bitsize, input_bfd, where);
relocation += addend;
@@ -477,28 +278,7 @@ bpf_elf_relocate_section (bfd *output_bfd ATTRIBUTE_UNUSED,
r = bfd_reloc_ok;
break;
}
case R_BPF_INSN_16:
{
addend = bfd_get_16 (input_bfd, where + 2);
relocation += addend;
bfd_put_16 (input_bfd, relocation, where + 2);
r = bfd_reloc_ok;
break;
}
case R_BPF_INSN_32:
{
/* Write relocated value */
addend = bfd_get_32 (input_bfd, where + 4);
relocation += addend;
bfd_put_32 (input_bfd, relocation, where + 4);
r = bfd_reloc_ok;
break;
}
case R_BPF_INSN_64:
case R_BPF_64_64:
{
/*
LDDW instructions are 128 bits long, with a 64-bit immediate.
@@ -610,7 +390,7 @@ bpf_elf_generic_reloc (bfd *abfd, arelent *reloc_entry, asymbol *symbol,
/* 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_INSN_64)
if (reloc_entry->howto->type == R_BPF_64_64)
reloc_size = 16;
else
reloc_size = (reloc_entry->howto->bitsize
@@ -642,7 +422,7 @@ bpf_elf_generic_reloc (bfd *abfd, arelent *reloc_entry, asymbol *symbol,
return status;
/* Now finally install the relocation. */
if (reloc_entry->howto->type == R_BPF_INSN_64)
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

3
bfd/libbfd.h
View File

@@ -3340,9 +3340,6 @@ static const char *const bfd_reloc_code_real_names[] = { "@@uninitialized@@",
"BFD_RELOC_TILEGX_IMM8_Y0_TLS_ADD",
"BFD_RELOC_TILEGX_IMM8_Y1_TLS_ADD",
"BFD_RELOC_BPF_64",
"BFD_RELOC_BPF_32",
"BFD_RELOC_BPF_16",
"BFD_RELOC_BPF_DISP16",
"BFD_RELOC_BPF_DISP32",
"BFD_RELOC_EPIPHANY_SIMM8",
"BFD_RELOC_EPIPHANY_SIMM24",

6
bfd/reloc.c
View File

@@ -7749,12 +7749,6 @@ ENUMDOC
ENUM
BFD_RELOC_BPF_64
ENUMX
BFD_RELOC_BPF_32
ENUMX
BFD_RELOC_BPF_16
ENUMX
BFD_RELOC_BPF_DISP16
ENUMX
BFD_RELOC_BPF_DISP32
ENUMDOC

7
gas/config/tc-bpf.c
View File

@@ -274,15 +274,8 @@ md_cgen_lookup_reloc (const CGEN_INSN *insn ATTRIBUTE_UNUSED,
{
switch (operand->type)
{
case BPF_OPERAND_OFFSET16:
return BFD_RELOC_BPF_16;
case BPF_OPERAND_IMM32:
return BFD_RELOC_BPF_32;
case BPF_OPERAND_IMM64:
return BFD_RELOC_BPF_64;
case BPF_OPERAND_DISP16:
fixP->fx_pcrel = 1;
return BFD_RELOC_BPF_DISP16;
case BPF_OPERAND_DISP32:
fixP->fx_pcrel = 1;
return BFD_RELOC_BPF_DISP32;

22
include/elf/bpf.h
View File

@@ -26,20 +26,14 @@
/* Relocations. */
START_RELOC_NUMBERS (elf_bpf_reloc_type)
RELOC_NUMBER (R_BPF_NONE, 0)
RELOC_NUMBER (R_BPF_INSN_64, 1)
RELOC_NUMBER (R_BPF_INSN_32, 2)
RELOC_NUMBER (R_BPF_INSN_16, 3)
RELOC_NUMBER (R_BPF_INSN_DISP16, 4)
RELOC_NUMBER (R_BPF_DATA_8_PCREL, 5)
RELOC_NUMBER (R_BPF_DATA_16_PCREL, 6)
RELOC_NUMBER (R_BPF_DATA_32_PCREL, 7)
RELOC_NUMBER (R_BPF_DATA_8, 8)
RELOC_NUMBER (R_BPF_DATA_16, 9)
RELOC_NUMBER (R_BPF_INSN_DISP32, 10)
RELOC_NUMBER (R_BPF_DATA_32, 11)
RELOC_NUMBER (R_BPF_DATA_64, 12)
RELOC_NUMBER (R_BPF_DATA_64_PCREL, 13)
RELOC_NUMBER (R_BPF_NONE, 0)
RELOC_NUMBER (R_BPF_64_64, 1)
RELOC_NUMBER (R_BPF_64_ABS64, 2)
RELOC_NUMBER (R_BPF_64_ABS32, 3)
/* R_BPF_64_NODYLD32 is not used by GNU tools.
* It is kept in this file to remind that the value is already taken. */
RELOC_NUMBER (R_BPF_64_NODYLD32, 4)
RELOC_NUMBER (R_BPF_64_32, 10)
END_RELOC_NUMBERS (R_BPF_max)
#endif /* _ELF_BPF_H */