diff options
Diffstat (limited to 'ld/ldlang.c')
| -rw-r--r-- | ld/ldlang.c | 73 |
1 files changed, 34 insertions, 39 deletions
diff --git a/ld/ldlang.c b/ld/ldlang.c index b074169..c96c21f 100644 --- a/ld/ldlang.c +++ b/ld/ldlang.c @@ -5382,56 +5382,51 @@ lang_size_sections (bfd_boolean *relax, bfd_boolean check_regions) if (expld.dataseg.phase == exp_dataseg_end_seen && link_info.relro && expld.dataseg.relro_end) { - bfd_vma initial_base, min_base, relro_end, maxpage; + bfd_vma initial_base, relro_end, desired_end; + asection *sec; - expld.dataseg.phase = exp_dataseg_relro_adjust; - maxpage = expld.dataseg.maxpagesize; - initial_base = expld.dataseg.base; - /* Try to put expld.dataseg.relro_end on a (common) page boundary. */ - expld.dataseg.base += (-expld.dataseg.relro_end - & (expld.dataseg.pagesize - 1)); /* Compute the expected PT_GNU_RELRO segment end. */ relro_end = ((expld.dataseg.relro_end + expld.dataseg.pagesize - 1) & ~(expld.dataseg.pagesize - 1)); - /* MIN_BASE is the absolute minimum address we are allowed to start the - read-write segment (byte before will be mapped read-only). */ - min_base = (expld.dataseg.min_base + maxpage - 1) & ~(maxpage - 1); - if (min_base + maxpage < expld.dataseg.base) - { - expld.dataseg.base -= maxpage; - relro_end -= maxpage; - } + + /* Adjust by the offset arg of DATA_SEGMENT_RELRO_END. */ + desired_end = relro_end - expld.dataseg.relro_offset; + + /* For sections in the relro segment.. */ + for (sec = link_info.output_bfd->section_last; sec; sec = sec->prev) + if (!IGNORE_SECTION (sec) + && sec->vma >= expld.dataseg.base + && sec->vma < expld.dataseg.relro_end - expld.dataseg.relro_offset) + { + /* Where do we want to put this section so that it ends as + desired? */ + bfd_vma start = sec->vma; + bfd_vma end = start + sec->size; + bfd_vma bump = desired_end - end; + /* We'd like to increase START by BUMP, but we must heed + alignment so the increase might be less than optimum. */ + start += bump & ~(((bfd_vma) 1 << sec->alignment_power) - 1); + /* This is now the desired end for the previous section. */ + desired_end = start; + } + + expld.dataseg.phase = exp_dataseg_relro_adjust; + ASSERT (desired_end >= expld.dataseg.base); + initial_base = expld.dataseg.base; + expld.dataseg.base = desired_end; lang_reset_memory_regions (); one_lang_size_sections_pass (relax, check_regions); + if (expld.dataseg.relro_end > relro_end) { - /* The alignment of sections between DATA_SEGMENT_ALIGN - and DATA_SEGMENT_RELRO_END can cause excessive padding to - be inserted at DATA_SEGMENT_RELRO_END. Try to start a - bit lower so that the section alignments will fit in. */ - asection *sec; - unsigned int max_alignment_power = 0; - - /* Find maximum alignment power of sections between - DATA_SEGMENT_ALIGN and DATA_SEGMENT_RELRO_END. */ - for (sec = link_info.output_bfd->sections; sec; sec = sec->next) - if (sec->vma >= expld.dataseg.base - && sec->vma < expld.dataseg.relro_end - && sec->alignment_power > max_alignment_power) - max_alignment_power = sec->alignment_power; - - /* Aligning the adjusted base guarantees the padding - between sections won't change. This is better than - simply subtracting 1 << max_alignment_power which is - what we used to do here. */ - expld.dataseg.base &= ~(((bfd_vma) 1 << max_alignment_power) - 1); - /* It doesn't make much sense to go lower than the initial - base. That can only increase padding. */ - if (expld.dataseg.base < initial_base) - expld.dataseg.base = initial_base; + /* Assignments to dot, or to output section address in a + user script have increased padding over the original. + Revert. */ + expld.dataseg.base = initial_base; lang_reset_memory_regions (); one_lang_size_sections_pass (relax, check_regions); } + link_info.relro_start = expld.dataseg.base; link_info.relro_end = expld.dataseg.relro_end; } |