ld: Add lang_size_relro_segment
Break lang_size_sections down into separate functions so that they can also be used for text-only LOAD segment. lang_size_relro_segment will call lang_size_relro_segment_1 and lang_size_segment for both GNU_RELRO segment and text-only LOAD segment. * ldlang.c (lang_size_segment): New function. (lang_size_relro_segment_1): Likewise. (lang_size_relro_segment): Likewise. (lang_size_sections): Rewrite to call lang_size_relro_segment.
This commit is contained in:
H.J. Lu
parent
d7475e036f
commit
cba6246d3a
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@ -1,3 +1,10 @@
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2017-11-12 H.J. Lu <hongjiu.lu@intel.com>
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* ldlang.c (lang_size_segment): New function.
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(lang_size_relro_segment_1): Likewise.
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(lang_size_relro_segment): Likewise.
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(lang_size_sections): Rewrite to call lang_size_relro_segment.
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2017-11-12 H.J. Lu <hongjiu.lu@intel.com>
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* ldexp.c (fold_unary): Extract the DATA_SEGMENT_END case to ...
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196
ld/ldlang.c
196
ld/ldlang.c
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@ -5589,6 +5589,108 @@ one_lang_size_sections_pass (bfd_boolean *relax, bfd_boolean check_regions)
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0, 0, relax, check_regions);
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}
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static bfd_boolean
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lang_size_segment (seg_align_type *seg)
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{
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/* If XXX_SEGMENT_ALIGN XXX_SEGMENT_END pair was seen, check whether
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a page could be saved in the data segment. */
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bfd_vma first, last;
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first = -seg->base & (seg->pagesize - 1);
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last = seg->end & (seg->pagesize - 1);
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if (first && last
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&& ((seg->base & ~(seg->pagesize - 1))
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!= (seg->end & ~(seg->pagesize - 1)))
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&& first + last <= seg->pagesize)
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{
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seg->phase = exp_seg_adjust;
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return TRUE;
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}
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seg->phase = exp_seg_done;
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return FALSE;
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}
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static bfd_vma
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lang_size_relro_segment_1 (seg_align_type *seg)
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{
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bfd_vma relro_end, desired_end;
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asection *sec;
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/* Compute the expected PT_GNU_RELRO/PT_LOAD segment end. */
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relro_end = ((seg->relro_end + seg->pagesize - 1)
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& ~(seg->pagesize - 1));
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/* Adjust by the offset arg of XXX_SEGMENT_RELRO_END. */
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desired_end = relro_end - seg->relro_offset;
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/* For sections in the relro segment.. */
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for (sec = link_info.output_bfd->section_last; sec; sec = sec->prev)
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if ((sec->flags & SEC_ALLOC) != 0
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&& sec->vma >= seg->base
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&& sec->vma < seg->relro_end - seg->relro_offset)
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{
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/* Where do we want to put this section so that it ends as
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desired? */
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bfd_vma start, end, bump;
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end = start = sec->vma;
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if (!IS_TBSS (sec))
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end += TO_ADDR (sec->size);
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bump = desired_end - end;
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/* We'd like to increase START by BUMP, but we must heed
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alignment so the increase might be less than optimum. */
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start += bump;
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start &= ~(((bfd_vma) 1 << sec->alignment_power) - 1);
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/* This is now the desired end for the previous section. */
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desired_end = start;
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}
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seg->phase = exp_seg_relro_adjust;
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ASSERT (desired_end >= seg->base);
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seg->base = desired_end;
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return relro_end;
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}
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static bfd_boolean
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lang_size_relro_segment (bfd_boolean *relax, bfd_boolean check_regions)
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{
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bfd_boolean do_reset = FALSE;
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bfd_boolean do_data_relro;
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bfd_vma data_initial_base, data_relro_end;
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if (link_info.relro && expld.dataseg.relro_end)
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{
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do_data_relro = TRUE;
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data_initial_base = expld.dataseg.base;
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data_relro_end = lang_size_relro_segment_1 (&expld.dataseg);
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}
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else
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{
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do_data_relro = FALSE;
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data_initial_base = data_relro_end = 0;
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}
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if (do_data_relro)
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{
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lang_reset_memory_regions ();
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one_lang_size_sections_pass (relax, check_regions);
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/* Assignments to dot, or to output section address in a user
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script have increased padding over the original. Revert. */
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if (do_data_relro && expld.dataseg.relro_end > data_relro_end)
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{
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expld.dataseg.base = data_initial_base;;
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do_reset = TRUE;
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}
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}
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if (!do_data_relro && lang_size_segment (&expld.dataseg))
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do_reset = TRUE;
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return do_reset;
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}
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void
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lang_size_sections (bfd_boolean *relax, bfd_boolean check_regions)
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{
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@ -5596,83 +5698,27 @@ lang_size_sections (bfd_boolean *relax, bfd_boolean check_regions)
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expld.dataseg.phase = exp_seg_none;
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one_lang_size_sections_pass (relax, check_regions);
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if (expld.dataseg.phase == exp_seg_end_seen
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&& link_info.relro && expld.dataseg.relro_end)
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{
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bfd_vma initial_base, relro_end, desired_end;
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asection *sec;
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/* Compute the expected PT_GNU_RELRO segment end. */
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relro_end = ((expld.dataseg.relro_end + expld.dataseg.pagesize - 1)
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& ~(expld.dataseg.pagesize - 1));
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/* Adjust by the offset arg of DATA_SEGMENT_RELRO_END. */
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desired_end = relro_end - expld.dataseg.relro_offset;
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/* For sections in the relro segment.. */
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for (sec = link_info.output_bfd->section_last; sec; sec = sec->prev)
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if ((sec->flags & SEC_ALLOC) != 0
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&& sec->vma >= expld.dataseg.base
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&& sec->vma < expld.dataseg.relro_end - expld.dataseg.relro_offset)
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{
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/* Where do we want to put this section so that it ends as
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desired? */
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bfd_vma start, end, bump;
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end = start = sec->vma;
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if (!IS_TBSS (sec))
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end += TO_ADDR (sec->size);
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bump = desired_end - end;
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/* We'd like to increase START by BUMP, but we must heed
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alignment so the increase might be less than optimum. */
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start += bump;
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start &= ~(((bfd_vma) 1 << sec->alignment_power) - 1);
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/* This is now the desired end for the previous section. */
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desired_end = start;
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}
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expld.dataseg.phase = exp_seg_relro_adjust;
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ASSERT (desired_end >= expld.dataseg.base);
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initial_base = expld.dataseg.base;
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expld.dataseg.base = desired_end;
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lang_reset_memory_regions ();
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one_lang_size_sections_pass (relax, check_regions);
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if (expld.dataseg.relro_end > relro_end)
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{
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/* Assignments to dot, or to output section address in a
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user script have increased padding over the original.
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Revert. */
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expld.dataseg.base = initial_base;
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lang_reset_memory_regions ();
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one_lang_size_sections_pass (relax, check_regions);
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}
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link_info.relro_start = expld.dataseg.base;
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link_info.relro_end = expld.dataseg.relro_end;
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}
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else if (expld.dataseg.phase == exp_seg_end_seen)
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{
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/* If DATA_SEGMENT_ALIGN DATA_SEGMENT_END pair was seen, check whether
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a page could be saved in the data segment. */
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bfd_vma first, last;
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first = -expld.dataseg.base & (expld.dataseg.pagesize - 1);
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last = expld.dataseg.end & (expld.dataseg.pagesize - 1);
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if (first && last
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&& ((expld.dataseg.base & ~(expld.dataseg.pagesize - 1))
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!= (expld.dataseg.end & ~(expld.dataseg.pagesize - 1)))
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&& first + last <= expld.dataseg.pagesize)
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{
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expld.dataseg.phase = exp_seg_adjust;
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lang_reset_memory_regions ();
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one_lang_size_sections_pass (relax, check_regions);
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}
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else
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expld.dataseg.phase = exp_seg_done;
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}
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else
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if (expld.dataseg.phase != exp_seg_end_seen)
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expld.dataseg.phase = exp_seg_done;
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if (expld.dataseg.phase == exp_seg_end_seen)
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{
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bfd_boolean do_reset
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= lang_size_relro_segment (relax, check_regions);
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if (do_reset)
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{
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lang_reset_memory_regions ();
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one_lang_size_sections_pass (relax, check_regions);
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}
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if (link_info.relro && expld.dataseg.relro_end)
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{
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link_info.relro_start = expld.dataseg.base;
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link_info.relro_end = expld.dataseg.relro_end;
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}
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}
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}
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static lang_output_section_statement_type *current_section;
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