diff --git a/bfd/elf64-s390.c b/bfd/elf64-s390.c index 3925cf6494d3..4730cc2cdb54 100644 --- a/bfd/elf64-s390.c +++ b/bfd/elf64-s390.c @@ -852,6 +852,7 @@ elf_s390_copy_indirect_symbol (struct bfd_link_info *info, dir->ref_regular |= ind->ref_regular; dir->ref_regular_nonweak |= ind->ref_regular_nonweak; dir->needs_plt |= ind->needs_plt; + dir->pointer_equality_needed |= ind->pointer_equality_needed; } else _bfd_elf_link_hash_copy_indirect (info, dir, ind); @@ -1037,6 +1038,7 @@ elf_s390_check_relocs (bfd *abfd, referenced. */ h->ref_regular = 1; h->needs_plt = 1; + h->pointer_equality_needed = 1; } } @@ -1078,6 +1080,38 @@ elf_s390_check_relocs (bfd *abfd, { h->needs_plt = 1; h->plt.refcount += 1; + + /* GCC 12-14 unconditionally suffix non-local symbols + with @PLT, regardless of whether they are used in + function call instructions (i.e. brasl) or address + taking instructions (i.e. larl). Treat PLT32DBL + relocation for "larl rX,@PLT" instruction as + address taking and require pointer equality. */ + if (bfd_link_executable (info) + && r_type == R_390_PLT32DBL + && rel->r_offset >= 2) + { + bfd_byte *contents; + void *insn_start; + uint16_t op; + + if (elf_section_data (sec)->this_hdr.contents != NULL) + contents = elf_section_data (sec)->this_hdr.contents; + else if (!_bfd_elf_mmap_section_contents (abfd, sec, &contents)) + return false; + + insn_start = contents + rel->r_offset - 2; + op = bfd_get_16 (abfd, insn_start) & 0xff0f; + + if (op == 0xc000) + { + /* larl rX,@PLT */ + h->pointer_equality_needed = 1; + } + + if (elf_section_data (sec)->this_hdr.contents != contents) + _bfd_elf_munmap_section_contents (sec, contents); + } } break; @@ -1227,6 +1261,12 @@ elf_s390_check_relocs (bfd *abfd, refers to is in a shared lib. */ h->plt.refcount += 1; } + + /* Require pointer equality in PDE for above PC-relative + relocations, that are likely in address taken context, + and direct relocations, that are likely in function + reference context. */ + h->pointer_equality_needed = 1; } /* If we are creating a shared library, and this is a reloc @@ -3692,11 +3732,16 @@ elf_s390_finish_dynamic_symbol (bfd *output_bfd, if (!h->def_regular) { /* Mark the symbol as undefined, rather than as defined in - the .plt section. Leave the value alone. This is a clue + the .plt section. Leave the value if there were any + relocations where pointer equality matters (this is a clue for the dynamic linker, to make function pointer comparisons work between an application and shared - library. */ + library), otherwise set it to zero. If a function is only + called from a binary, there is no need to slow down + shared libraries because of that. */ sym->st_shndx = SHN_UNDEF; + if (!h->pointer_equality_needed) + sym->st_value = 0; } } } @@ -3730,6 +3775,9 @@ elf_s390_finish_dynamic_symbol (bfd *output_bfd, } else { + if (!h->pointer_equality_needed) + abort (); + /* For non-shared objects explicit GOT slots must be filled with the PLT slot address for pointer equality reasons. */ @@ -4344,6 +4392,19 @@ elf_s390_create_dynamic_sections (bfd *dynobj, return true; } +/* Return TRUE if symbol should be hashed in the `.gnu.hash' section. */ + +static bool +elf_s390_hash_symbol (struct elf_link_hash_entry *h) +{ + if (h->plt.offset != (bfd_vma) -1 + && !h->def_regular + && !h->pointer_equality_needed) + return false; + + return _bfd_elf_hash_symbol (h); +} + /* Why was the hash table entry size definition changed from ARCH_SIZE/8 to 4? This breaks the 64 bit dynamic linker and this is the only reason for the s390_elf64_size_info structure. */ @@ -4424,6 +4485,7 @@ static const struct elf_size_info s390_elf64_size_info = #define elf_backend_sort_relocs_p elf_s390_elf_sort_relocs_p #define elf_backend_additional_program_headers elf_s390_additional_program_headers #define elf_backend_modify_segment_map elf_s390_modify_segment_map +#define elf_backend_hash_symbol elf_s390_hash_symbol #define bfd_elf64_mkobject elf_s390_mkobject #define elf_backend_object_p elf_s390_object_p diff --git a/ld/testsuite/ld-elf/pr29655.rd b/ld/testsuite/ld-elf/pr29655.rd new file mode 100644 index 000000000000..b294ca95a641 --- /dev/null +++ b/ld/testsuite/ld-elf/pr29655.rd @@ -0,0 +1,5 @@ +Symbol table '\.dynsym' contains [0-9]+ entries: + +Num: +Value +Size Type +Bind +Vis +Ndx Name +#... + +[0-9]+: +0+ +0 +FUNC +GLOBAL +DEFAULT +UND +fun_public +#... diff --git a/ld/testsuite/ld-elf/pr29655a.c b/ld/testsuite/ld-elf/pr29655a.c new file mode 100644 index 000000000000..e523f82d4564 --- /dev/null +++ b/ld/testsuite/ld-elf/pr29655a.c @@ -0,0 +1,20 @@ +#include + +typedef void Fn(); + +void __attribute__((visibility("hidden"))) +fun (void) +{} + +extern void fun_public() __attribute__((alias("fun"))); + +void +call_callback (Fn *callback) +{ + if (callback == fun) + printf("PASS\n"); + else + printf("FAIL\n"); + + callback (); +} diff --git a/ld/testsuite/ld-elf/pr29655b.c b/ld/testsuite/ld-elf/pr29655b.c new file mode 100644 index 000000000000..527fd462b944 --- /dev/null +++ b/ld/testsuite/ld-elf/pr29655b.c @@ -0,0 +1,15 @@ +#ifndef __PIC__ +#error "this file must be compiled with -fPIC" +#endif + +typedef void Fn(); +void fun_public(void); +void call_callback(Fn *callback); + +int +main () +{ + fun_public (); + call_callback (fun_public); + return 0; +} diff --git a/ld/testsuite/ld-elf/shared.exp b/ld/testsuite/ld-elf/shared.exp index 808ad6ffdb6c..a44a65b3428b 100644 --- a/ld/testsuite/ld-elf/shared.exp +++ b/ld/testsuite/ld-elf/shared.exp @@ -1863,3 +1863,33 @@ run_ld_link_tests [list \ "pr23658-2" \ ] \ ] + +# PR 29655 +run_cc_link_tests [list \ + [list \ + "Build pr29655.so" \ + "-shared" \ + "-fPIC" \ + { pr29655a.c } \ + {} \ + "pr29655.so" \ + ] \ +] +# PR 29655 (cont.): Check that in PIC code linked as PDE taking the address +# of a function defined in a DSO results in the function address (from GOT) +# and not the "canonical PLT" address from the PDE. +# This is just an optimization and both is valid, although libraries may +# depend on this specific behavior, so do not complain loudly. +setup_xfail *-*-* +clear_xfail aarch64-*-* alpha-*-* arm*-*-* hppa-*-* i?86-*-* ia64-*-* \ + microblaze-*-* mips-*-* mips64-*-* powerpc*-*-* s390x-*-* x86_64-*-* +run_cc_link_tests [list \ + [list \ + "Build pr29655" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed,-rpath,tmpdir tmpdir/pr29655.so" \ + "-fPIC" \ + { pr29655b.c } \ + {{readelf {--dyn-syms --wide} pr29655.rd}} \ + "pr29655" \ + ] \ +] diff --git a/ld/testsuite/ld-s390/plt_64-1.wf b/ld/testsuite/ld-s390/plt_64-1.wf index 61dc4c7a9894..eac5502e111b 100644 --- a/ld/testsuite/ld-s390/plt_64-1.wf +++ b/ld/testsuite/ld-s390/plt_64-1.wf @@ -19,14 +19,14 @@ Contents of the .eh_frame section: DW_CFA_nop DW_CFA_nop -00000018 000000000000001c 0000001c FDE cie=00000000 pc=00000000010002b8..00000000010002e4 +00000018 000000000000001c 0000001c FDE cie=00000000 pc=00000000010002b0..00000000010002dc DW_CFA_remember_state - DW_CFA_advance_loc: 6 to 00000000010002be + DW_CFA_advance_loc: 6 to 00000000010002b6 DW_CFA_offset: r14 at cfa-48 DW_CFA_offset: r15 at cfa-40 - DW_CFA_advance_loc: 8 to 00000000010002c6 + DW_CFA_advance_loc: 8 to 00000000010002be DW_CFA_def_cfa_offset: 320 - DW_CFA_advance_loc: 24 to 00000000010002de + DW_CFA_advance_loc: 24 to 00000000010002d6 DW_CFA_restore_state DW_CFA_nop DW_CFA_nop diff --git a/ld/testsuite/ld-s390/plt_64-1_eh.wf b/ld/testsuite/ld-s390/plt_64-1_eh.wf index 717e7a7e2a61..794aeee23864 100644 --- a/ld/testsuite/ld-s390/plt_64-1_eh.wf +++ b/ld/testsuite/ld-s390/plt_64-1_eh.wf @@ -19,7 +19,7 @@ Contents of the .eh_frame section: DW_CFA_nop DW_CFA_nop -00000018 0000000000000014 0000001c FDE cie=00000000 pc=0000000001000258..00000000010002b8 +00000018 0000000000000014 0000001c FDE cie=00000000 pc=0000000001000250..00000000010002b0 DW_CFA_nop DW_CFA_nop DW_CFA_nop