| From c7cd291722779c9d4703ed0010388fe394c644c8 Mon Sep 17 00:00:00 2001 |
| From: Siddhesh Poyarekar <siddesh.poyarekar@arm.com> |
| Date: Tue, 1 Sep 2020 14:25:52 +0530 |
| Subject: [PATCH] aarch64: Return an error on conditional branch to an undefined symbol |
| |
| The fix in 7e05773767820b441b23a16628b55c98cb1aef46 introduced a PLT |
| for conditional jumps when the target symbol is undefined. This is |
| incorrect because conditional branch relocations are not allowed to |
| clobber IP0/IP1 and hence, should not result in a dynamic relocation. |
| |
| Revert that change and in its place, issue an error when the target |
| symbol is undefined. |
| |
| bfd/ |
| |
| 2020-09-10 Siddhesh Poyarekar <siddesh.poyarekar@arm.com> |
| |
| * elfnn-aarch64.c (elfNN_aarch64_final_link_relocate): Revert |
| changes in 7e05773767820b441b23a16628b55c98cb1aef46. Set |
| error for undefined symbol in BFD_RELOC_AARCH64_BRANCH19 and |
| BFD_RELOC_AARCH64_TSTBR14 relocations. |
| |
| ld/ |
| |
| 2020-09-10 Siddhesh Poyarekar <siddesh.poyarekar@arm.com> |
| |
| * testsuite/ld-aarch64/emit-relocs-560.d: Expect error instead |
| of valid output. |
| --- |
| Upstream-Status: Backport [https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c7cd291722779c9d4703ed0010388fe394c644c8] |
| Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| |
| bfd/ChangeLog | 7 +++++ |
| bfd/elfnn-aarch64.c | 37 ++++++++++++----------- |
| ld/ChangeLog | 5 +++ |
| ld/testsuite/ld-aarch64/emit-relocs-560.d | 7 +---- |
| 4 files changed, 32 insertions(+), 24 deletions(-) |
| |
| diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c |
| index 5b4c189b593..a9924e7ec56 100644 |
| --- a/bfd/elfnn-aarch64.c |
| +++ b/bfd/elfnn-aarch64.c |
| @@ -5447,7 +5447,6 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, |
| bfd_vma orig_value = value; |
| bfd_boolean resolved_to_zero; |
| bfd_boolean abs_symbol_p; |
| - bfd_boolean via_plt_p; |
| |
| globals = elf_aarch64_hash_table (info); |
| |
| @@ -5469,8 +5468,6 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, |
| : bfd_is_und_section (sym_sec)); |
| abs_symbol_p = h != NULL && bfd_is_abs_symbol (&h->root); |
| |
| - via_plt_p = (globals->root.splt != NULL && h != NULL |
| - && h->plt.offset != (bfd_vma) - 1); |
| |
| /* Since STT_GNU_IFUNC symbol must go through PLT, we handle |
| it here if it is defined in a non-shared object. */ |
| @@ -5806,23 +5803,12 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, |
| value += signed_addend; |
| break; |
| |
| - case BFD_RELOC_AARCH64_BRANCH19: |
| - case BFD_RELOC_AARCH64_TSTBR14: |
| - /* A conditional branch to an undefined weak symbol is converted to a |
| - branch to itself. */ |
| - if (weak_undef_p && !via_plt_p) |
| - { |
| - value = _bfd_aarch64_elf_resolve_relocation (input_bfd, bfd_r_type, |
| - place, value, |
| - signed_addend, |
| - weak_undef_p); |
| - break; |
| - } |
| - /* Fall through. */ |
| case BFD_RELOC_AARCH64_CALL26: |
| case BFD_RELOC_AARCH64_JUMP26: |
| { |
| asection *splt = globals->root.splt; |
| + bfd_boolean via_plt_p = |
| + splt != NULL && h != NULL && h->plt.offset != (bfd_vma) - 1; |
| |
| /* A call to an undefined weak symbol is converted to a jump to |
| the next instruction unless a PLT entry will be created. |
| @@ -5903,6 +5889,23 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto, |
| bfd_set_error (bfd_error_bad_value); |
| return bfd_reloc_notsupported; |
| } |
| + value = _bfd_aarch64_elf_resolve_relocation (input_bfd, bfd_r_type, |
| + place, value, |
| + signed_addend, |
| + weak_undef_p); |
| + break; |
| + |
| + case BFD_RELOC_AARCH64_BRANCH19: |
| + case BFD_RELOC_AARCH64_TSTBR14: |
| + if (h && h->root.type == bfd_link_hash_undefined) |
| + { |
| + _bfd_error_handler |
| + /* xgettext:c-format */ |
| + (_("%pB: conditional branch to undefined symbol `%s' " |
| + "not allowed"), input_bfd, h->root.root.string); |
| + bfd_set_error (bfd_error_bad_value); |
| + return bfd_reloc_notsupported; |
| + } |
| /* Fall through. */ |
| |
| case BFD_RELOC_AARCH64_16: |
| @@ -7968,8 +7971,6 @@ elfNN_aarch64_check_relocs (bfd *abfd, struct bfd_link_info *info, |
| break; |
| } |
| |
| - case BFD_RELOC_AARCH64_BRANCH19: |
| - case BFD_RELOC_AARCH64_TSTBR14: |
| case BFD_RELOC_AARCH64_CALL26: |
| case BFD_RELOC_AARCH64_JUMP26: |
| /* If this is a local symbol then we resolve it |
| diff --git a/ld/testsuite/ld-aarch64/emit-relocs-560.d b/ld/testsuite/ld-aarch64/emit-relocs-560.d |
| index 153532457b4..8751b743bd4 100644 |
| --- a/ld/testsuite/ld-aarch64/emit-relocs-560.d |
| +++ b/ld/testsuite/ld-aarch64/emit-relocs-560.d |
| @@ -1,8 +1,3 @@ |
| #source: emit-relocs-560.s |
| #ld: -shared |
| -#readelf: -r |
| - |
| -Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 2 entries: |
| - Offset Info Type Sym. Value Sym. Name \+ Addend |
| -[0-9a-f]+ 000100000402 R_AARCH64_JUMP_SL 0000000000000000 baz \+ 0 |
| -[0-9a-f]+ 000200000402 R_AARCH64_JUMP_SL 0000000000000000 bar \+ 0 |
| +#error: .*: conditional branch to undefined symbol `bar' not allowed |
| -- |
| 2.29.2 |
| |