From: Nelson Chu Date: Sat, 25 Mar 2023 00:41:12 +0000 (+0800) Subject: RISC-V: Clarify link behaviors of R_RISCV_32/64 relocations with ABS symbol. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b679fb488a8c35e573d50f118a09f72c1f6289de;p=binutils-gdb.git RISC-V: Clarify link behaviors of R_RISCV_32/64 relocations with ABS symbol. There are two improvements, which are all referenced to aarch64, * R_RISCV_32 with non ABS symbol cannot be used under RV64 when making shard objects. * Don't need dynamic relocation for R_RISCV_32/64 under RV32/RV64 when making shared objects, if the referenced symbol is local ABS symbol. However, considering this link, https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/341 Seems like we should makes all R_RISCV_32/64 relocs with ABS symbol that don't need any dynamic relocations when making the shared objects. But anyway, I just sync the current behavior as aarch64 ld, in case there are any unexpected behaviors happen. Passed the gcc/binutils regressions in riscv-gnu-toolchain. bfd/ * elfnn-riscv.c (riscv_elf_check_relocs): Only allow R_RISCV_32 with ABS symbol under RV64. (riscv_elf_relocate_section): R_RISCV_32/64 with local ABS symbol under RV32/RV64 doesn't need any dynamic relocation when making shared objects. I just make the implementations similar to other targets, so that will be more easy to mainatain. ld/ * testsuite/ld-riscv-elf/data-reloc*: New testcases. * testsuite/ld-riscv-elf/ld-riscv-elf.exp: Added new data-reloc* testcases, and need to make ifunc-seperate* testcases work for rv32. * testsuite/ld-riscv-elf/ifunc-seperate-caller-nonplt.s: Likewise. * testsuite/ld-riscv-elf/ifunc-seperate-caller-plt.s: Likewise. --- diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c index 59e949a2cb5..00f034a6751 100644 --- a/bfd/elfnn-riscv.c +++ b/bfd/elfnn-riscv.c @@ -734,6 +734,7 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info, unsigned int r_type; unsigned int r_symndx; struct elf_link_hash_entry *h; + bool is_abs_symbol = false; r_symndx = ELFNN_R_SYM (rel->r_info); r_type = ELFNN_R_TYPE (rel->r_info); @@ -753,6 +754,8 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info, if (isym == NULL) return false; + is_abs_symbol = isym->st_shndx == SHN_ABS ? true : false; + /* Check relocation against local STT_GNU_IFUNC symbol. */ if (ELF_ST_TYPE (isym->st_info) == STT_GNU_IFUNC) { @@ -778,6 +781,8 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info, while (h->root.type == bfd_link_hash_indirect || h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; + + is_abs_symbol = bfd_is_abs_symbol (&h->root) ? true : false; } if (h != NULL) @@ -879,13 +884,31 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info, case R_RISCV_HI20: if (bfd_link_pic (info)) return bad_static_reloc (abfd, r_type, h); - /* Fall through. */ + goto static_reloc; + + case R_RISCV_32: + if (ARCH_SIZE > 32 + && bfd_link_pic (info) + && (sec->flags & SEC_ALLOC) != 0) + { + if (is_abs_symbol) + break; + + reloc_howto_type *r_t = riscv_elf_rtype_to_howto (abfd, r_type); + _bfd_error_handler + (_("%pB: relocation %s against non-absolute symbol `%s' can " + "not be used in RVNN when making a shared object"), + abfd, r_t ? r_t->name : _(""), + h != NULL ? h->root.root.string : "a local symbol"); + bfd_set_error (bfd_error_bad_value); + return false; + } + goto static_reloc; case R_RISCV_COPY: case R_RISCV_JUMP_SLOT: case R_RISCV_RELATIVE: case R_RISCV_64: - case R_RISCV_32: /* Fall through. */ static_reloc: @@ -2630,6 +2653,11 @@ riscv_elf_relocate_section (bfd *output_bfd, break; case R_RISCV_32: + /* Non ABS symbol should be blocked in check_relocs. */ + if (ARCH_SIZE > 32) + break; + /* Fall through. */ + case R_RISCV_64: if ((input_section->flags & SEC_ALLOC) == 0) break; @@ -2639,7 +2667,6 @@ riscv_elf_relocate_section (bfd *output_bfd, { Elf_Internal_Rela outrel; asection *sreloc; - bool skip_static_relocation, skip_dynamic_relocation; /* When generating a shared object, these relocations are copied into the output file to be resolved at run @@ -2648,26 +2675,44 @@ riscv_elf_relocate_section (bfd *output_bfd, outrel.r_offset = _bfd_elf_section_offset (output_bfd, info, input_section, rel->r_offset); - skip_static_relocation = outrel.r_offset != (bfd_vma) -2; - skip_dynamic_relocation = outrel.r_offset >= (bfd_vma) -2; + bool skip = false; + bool relocate = false; + if (outrel.r_offset == (bfd_vma) -1) + skip = true; + else if (outrel.r_offset == (bfd_vma) -2) + { + skip = true; + relocate = true; + } + else if (h != NULL && bfd_is_abs_symbol (&h->root)) + { + /* Don't need dynamic reloc when the ABS symbol is + non-dynamic or forced to local. Maybe just use + SYMBOL_REFERENCES_LOCAL to check? */ + skip = (h->forced_local || (h->dynindx == -1)); + relocate = skip; + } + outrel.r_offset += sec_addr (input_section); - if (skip_dynamic_relocation) - memset (&outrel, 0, sizeof outrel); + if (skip) + memset (&outrel, 0, sizeof outrel); /* R_RISCV_NONE. */ else if (RISCV_COPY_INPUT_RELOC (info, h)) { + /* Maybe just use !SYMBOL_REFERENCES_LOCAL to check? */ outrel.r_info = ELFNN_R_INFO (h->dynindx, r_type); outrel.r_addend = rel->r_addend; } else { + /* This symbol is local, or marked to become local. */ outrel.r_info = ELFNN_R_INFO (0, R_RISCV_RELATIVE); outrel.r_addend = relocation + rel->r_addend; } sreloc = elf_section_data (input_section)->sreloc; riscv_elf_append_rela (output_bfd, sreloc, &outrel); - if (skip_static_relocation) + if (!relocate) continue; } break; diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv32-pic.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv32-pic.d new file mode 100644 index 00000000000..13f34e052b7 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv32-pic.d @@ -0,0 +1,21 @@ +#source: data-reloc.s +#as: -march=rv32i -mabi=ilp32 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1 +#ld: -m[riscv_choose_ilp32_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared +#objdump: -dR + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+8000 : + 8000: 00000000 .word 0x00000000 + 8000: R_RISCV_32 addr_globl + +0+8004 : + ... + 8004: R_RISCV_RELATIVE \*ABS\*\+0x8004 + 8008: R_RISCV_32 abs + 800c: 00000200 .word 0x00000200 + 8010: 00000000 .word 0x00000000 + 8010: R_RISCV_32 undef diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv32-pie.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv32-pie.d new file mode 100644 index 00000000000..1e8f35a9c18 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv32-pie.d @@ -0,0 +1,18 @@ +#source: data-reloc.s +#as: -march=rv32i -mabi=ilp32 -defsym __abs__=1 -defsym __addr__=1 +#ld: -m[riscv_choose_ilp32_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -pie +#objdump: -dR + +.*:[ ]+file format .* + +Disassembly of section .text: + +0+8000 : + 8000: 00000000 .word 0x00000000 + 8000: R_RISCV_RELATIVE \*ABS\*\+0x8000 + +0+8004 : + 8004: 00000000 .word 0x00000000 + 8004: R_RISCV_RELATIVE \*ABS\*\+0x8004 + 8008: 00000100 .word 0x00000100 + 800c: 00000200 .word 0x00000200 diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv32-symbolic.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv32-symbolic.d new file mode 100644 index 00000000000..5c947e2b93b --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv32-symbolic.d @@ -0,0 +1,21 @@ +#source: data-reloc.s +#as: -march=rv32i -mabi=ilp32 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1 +#ld: -m[riscv_choose_ilp32_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared -Bsymbolic +#objdump: -dR + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+8000 : + 8000: 00000000 .word 0x00000000 + 8000: R_RISCV_RELATIVE \*ABS\*\+0x8000 + +0+8004 : + ... + 8004: R_RISCV_RELATIVE \*ABS\*\+0x8004 + 8008: R_RISCV_RELATIVE \*ABS\*\+0x100 + 800c: 00000200 .word 0x00000200 + 8010: 00000000 .word 0x00000000 + 8010: R_RISCV_32 undef diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-pic.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-pic.d new file mode 100644 index 00000000000..1d3686de353 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-pic.d @@ -0,0 +1,13 @@ +#source: data-reloc.s +#as: -march=rv64i -mabi=lp64 -defsym __abs__=1 +#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared +#objdump: -dR + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+8000 <.text>: + 8000: 00000100 .word 0x00000100 + 8004: 00000200 .word 0x00000200 diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv64-addr32-pic.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-addr32-pic.d new file mode 100644 index 00000000000..39b50e33044 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-addr32-pic.d @@ -0,0 +1,4 @@ +#source: data-reloc.s +#as: -march=rv64i -mabi=lp64 -defsym __addr__=1 +#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 -shared +#error: .*relocation R_RISCV_32 against non-absolute symbol `addr_globl' can not be used in RV64 when making a shared object.* diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv64-pic.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-pic.d new file mode 100644 index 00000000000..dab0ccc9260 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-pic.d @@ -0,0 +1,21 @@ +#source: data-reloc.s +#as: -march=rv64i -mabi=lp64 -defsym __64_bit__=1 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1 +#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared +#objdump: -dR + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+8000 : + ... + 8000: R_RISCV_64 addr_globl + +0+8008 : + ... + 8008: R_RISCV_RELATIVE \*ABS\*\+0x8008 + 8010: R_RISCV_64 abs + 8018: 00000200 .word 0x00000200 + ... + 8020: R_RISCV_64 undef diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv64-pie.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-pie.d new file mode 100644 index 00000000000..fd6c470f680 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-pie.d @@ -0,0 +1,21 @@ +#source: data-reloc.s +#as: -march=rv64i -mabi=lp64 -defsym __64_bit__=1 -defsym __abs__=1 -defsym __addr__=1 +#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -pie +#objdump: -dR + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+8000 : + ... + 8000: R_RISCV_RELATIVE \*ABS\*\+0x8000 + +0+8008 : + ... + 8008: R_RISCV_RELATIVE \*ABS\*\+0x8008 + 8010: 00000100 .word 0x00000100 + 8014: 00000000 .word 0x00000000 + 8018: 00000200 .word 0x00000200 + 801c: 00000000 .word 0x00000000 diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv64-symbolic.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-symbolic.d new file mode 100644 index 00000000000..5d41f869b72 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-symbolic.d @@ -0,0 +1,21 @@ +#source: data-reloc.s +#as: -march=rv64i -mabi=lp64 -defsym __64_bit__=1 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1 +#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared -Bsymbolic +#objdump: -dR + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+8000 : + ... + 8000: R_RISCV_RELATIVE \*ABS\*\+0x8000 + +0+8008 : + ... + 8008: R_RISCV_RELATIVE \*ABS\*\+0x8008 + 8010: R_RISCV_RELATIVE \*ABS\*\+0x100 + 8018: 00000200 .word 0x00000200 + ... + 8020: R_RISCV_64 undef diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv64-undef32-pic.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-undef32-pic.d new file mode 100644 index 00000000000..e5de484142c --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-undef32-pic.d @@ -0,0 +1,4 @@ +#source: data-reloc.s +#as: -march=rv64i -mabi=lp64 -defsym __undef__=1 +#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 -shared +#error: .*relocation R_RISCV_32 against non-absolute symbol `undef' can not be used in RV64 when making a shared object.* diff --git a/ld/testsuite/ld-riscv-elf/data-reloc.s b/ld/testsuite/ld-riscv-elf/data-reloc.s new file mode 100644 index 00000000000..37151500f77 --- /dev/null +++ b/ld/testsuite/ld-riscv-elf/data-reloc.s @@ -0,0 +1,22 @@ + .macro DATA symbol +.ifdef __64_bit__ + .quad \symbol +.else + .word \symbol +.endif + .endm +.ifdef __addr__ + .globl addr_globl +addr_globl: + DATA addr_globl +addr_local: + DATA addr_local +.endif +.ifdef __abs__ + .hidden abs_local + DATA abs + DATA abs_local +.endif +.ifdef __undef__ + DATA undef +.endif diff --git a/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-nonplt.s b/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-nonplt.s index 23c7254ad5b..df0d33b97e2 100644 --- a/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-nonplt.s +++ b/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-nonplt.s @@ -20,4 +20,4 @@ main: .data foo_addr: - .long foo + .quad foo diff --git a/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-plt.s b/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-plt.s index 8aa64034706..cc1608a9803 100644 --- a/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-plt.s +++ b/ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-plt.s @@ -23,4 +23,4 @@ main: .data foo_addr: - .long foo + .quad foo diff --git a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp index 5dd6144efd3..1b2a5ce2cb2 100644 --- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp +++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp @@ -217,6 +217,16 @@ if [istarget "riscv*-*-*"] { run_dump_test "shared-lib-nopic-03" run_dump_test "shared-lib-nopic-04" + run_dump_test "data-reloc-rv64-pic" + run_dump_test "data-reloc-rv64-pie" + run_dump_test "data-reloc-rv64-symbolic" + run_dump_test "data-reloc-rv32-pic" + run_dump_test "data-reloc-rv32-pie" + run_dump_test "data-reloc-rv32-symbolic" + run_dump_test "data-reloc-rv64-abs32-pic" + run_dump_test "data-reloc-rv64-addr32-pic" + run_dump_test "data-reloc-rv64-undef32-pic" + # IFUNC testcases. # Check IFUNC by single type relocs. run_dump_test_ifunc "ifunc-reloc-call-01" rv32 exe @@ -270,6 +280,11 @@ if [istarget "riscv*-*-*"] { run_dump_test_ifunc "ifunc-plt-got-overwrite" rv64 pie run_dump_test_ifunc "ifunc-plt-got-overwrite" rv64 pic + # TODO: Make the following tests work under RV32. + if [istarget "riscv32-*-*"] { + return + } + # Setup shared libraries. run_ld_link_tests { { "Build shared library for IFUNC non-PLT caller"