From 5e4c7a839d1c0d68a4a518cf2dc8e87925575e58 Mon Sep 17 00:00:00 2001 From: Cupertino Miranda Date: Thu, 16 Mar 2023 08:39:52 +0000 Subject: [PATCH] BPF relocations review / refactoring - 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. --- bfd/bfd-in2.h | 3 - bfd/bpf-reloc.def | 74 +++++++++++ bfd/elf64-bpf.c | 314 +++++++------------------------------------- bfd/libbfd.h | 3 - bfd/reloc.c | 6 - gas/config/tc-bpf.c | 7 - include/elf/bpf.h | 22 ++-- 7 files changed, 129 insertions(+), 300 deletions(-) create mode 100644 bfd/bpf-reloc.def diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h index 7c5953442aa..b60ff960f08 100644 --- a/bfd/bfd-in2.h +++ b/bfd/bfd-in2.h @@ -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 */ diff --git a/bfd/bpf-reloc.def b/bfd/bpf-reloc.def new file mode 100644 index 00000000000..b1be2eb66f6 --- /dev/null +++ b/bfd/bpf-reloc.def @@ -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 */ diff --git a/bfd/elf64-bpf.c b/bfd/elf64-bpf.c index 4f9949b515b..ef34d62df01 100644 --- a/bfd/elf64-bpf.c +++ b/bfd/elf64-bpf.c @@ -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]; - - 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]; + 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 diff --git a/bfd/libbfd.h b/bfd/libbfd.h index e75935133ac..fa6f2d71b60 100644 --- a/bfd/libbfd.h +++ b/bfd/libbfd.h @@ -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", diff --git a/bfd/reloc.c b/bfd/reloc.c index 346dd7638db..16540632613 100644 --- a/bfd/reloc.c +++ b/bfd/reloc.c @@ -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 diff --git a/gas/config/tc-bpf.c b/gas/config/tc-bpf.c index aa701584470..1f8b0cc2ede 100644 --- a/gas/config/tc-bpf.c +++ b/gas/config/tc-bpf.c @@ -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; diff --git a/include/elf/bpf.h b/include/elf/bpf.h index e52f481b2be..fb1936010bf 100644 --- a/include/elf/bpf.h +++ b/include/elf/bpf.h @@ -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 */ -- 2.30.2