static bfd_vma
lang_size_relro_segment_1 (seg_align_type *seg)
{
- bfd_vma relro_end, desired_end;
- asection *sec, *prev_sec = NULL;
- bool remove_page_gap = false;
+ bfd_vma relro_end, desired_relro_base;
+ asection *sec, *relro_sec = NULL;
unsigned int max_alignment_power = 0;
+ bool seen_reloc_section = false;
+ bool desired_relro_base_reduced = false;
/* Compute the expected PT_GNU_RELRO/PT_LOAD segment end. */
relro_end = ((seg->relro_end + seg->pagesize - 1)
& ~(seg->pagesize - 1));
/* Adjust by the offset arg of XXX_SEGMENT_RELRO_END. */
- desired_end = relro_end - seg->relro_offset;
+ desired_relro_base = relro_end - seg->relro_offset;
- /* For sections in the relro segment.. */
+ /* For sections in the relro segment. */
for (sec = link_info.output_bfd->section_last; sec; sec = sec->prev)
if ((sec->flags & SEC_ALLOC) != 0)
{
+ /* Record the maximum alignment for all sections starting from
+ the relro segment. */
if (sec->alignment_power > max_alignment_power)
max_alignment_power = sec->alignment_power;
if (sec->vma >= seg->base
&& sec->vma < seg->relro_end - seg->relro_offset)
{
- /* Where do we want to put this section so that it ends as
- desired? */
+ /* Where do we want to put the relro section so that the
+ relro segment ends on the page bounary? */
bfd_vma start, end, bump;
end = start = sec->vma;
if (!IS_TBSS (sec))
end += TO_ADDR (sec->size);
- bump = desired_end - end;
+ bump = desired_relro_base - end;
/* We'd like to increase START by BUMP, but we must heed
alignment so the increase might be less than optimum. */
start += bump;
start &= ~(((bfd_vma) 1 << sec->alignment_power) - 1);
/* This is now the desired end for the previous section. */
- desired_end = start;
- prev_sec = sec->prev;
+ desired_relro_base = start;
+ relro_sec = sec;
+ seen_reloc_section = true;
}
- }
-
- seg->phase = exp_seg_relro_adjust;
- ASSERT (desired_end >= seg->base);
-
- for (; prev_sec; prev_sec = prev_sec->prev)
- if ((prev_sec->flags & SEC_ALLOC) != 0)
- {
- if (prev_sec->alignment_power > max_alignment_power)
- max_alignment_power = prev_sec->alignment_power;
-
- if (prev_sec->size != 0)
+ else if (seen_reloc_section)
{
- /* The 1-page gap before the RELRO segment may be removed. */
- remove_page_gap = ((prev_sec->vma + prev_sec->size
- + seg->maxpagesize) < desired_end);
-
+ /* Stop searching if we see a non-relro section after seeing
+ relro sections. */
break;
}
}
- if (remove_page_gap)
+ if (relro_sec != NULL
+ && seg->maxpagesize >= (1U << max_alignment_power))
{
- /* Find the maximum section alignment. */
- for (sec = prev_sec; sec; sec = sec->prev)
- if ((sec->flags & SEC_ALLOC) != 0
- && sec->alignment_power > max_alignment_power)
- max_alignment_power = sec->alignment_power;
+ asection *prev_sec;
+ bfd_vma prev_sec_end_plus_1_page;
- /* Remove the 1-page gap before the RELRO segment only if the
- maximum page size >= the maximum section alignment. */
- if (seg->maxpagesize >= (1U << max_alignment_power))
+ /* Find the first preceding load section. */
+ for (prev_sec = relro_sec->prev;
+ prev_sec != NULL;
+ prev_sec = prev_sec->prev)
+ if ((prev_sec->flags & SEC_ALLOC) != 0)
+ break;
+
+ prev_sec_end_plus_1_page = (prev_sec->vma + prev_sec->size
+ + seg->maxpagesize);
+ if (prev_sec_end_plus_1_page < desired_relro_base)
{
- /* If the preceding section size is greater than the maximum
- page size, subtract the maximum page size. Otherwise,
- align the RELRO segment to the maximum page size. */
- if (prev_sec->size > seg->maxpagesize)
+ bfd_vma aligned_relro_base;
+
+ desired_relro_base_reduced = true;
+
+ /* Don't add the 1-page gap before the relro segment. Align
+ the relro segment first. */
+ aligned_relro_base = (desired_relro_base
+ & ~(seg->maxpagesize - 1));
+ if (prev_sec_end_plus_1_page < aligned_relro_base)
{
- desired_end -= seg->maxpagesize;
+ /* Subtract the maximum page size if therer is still a
+ 1-page gap. */
+ desired_relro_base -= seg->maxpagesize;
relro_end -= seg->maxpagesize;
}
else
{
- desired_end &= ~(seg->maxpagesize - 1);
+ /* Align the relro segment. */
+ desired_relro_base = aligned_relro_base;
relro_end &= ~(seg->maxpagesize - 1);
}
- }
- }
+ }
+ }
- seg->base = desired_end;
+ seg->phase = exp_seg_relro_adjust;
+ ASSERT (desired_relro_base_reduced
+ || desired_relro_base >= seg->base);
+ seg->base = desired_relro_base;
return relro_end;
}
--- /dev/null
+#as: --64
+#ld: -melf_x86_64 -shared -z relro -z now --hash-style=sysv -z max-page-size=0x1000 -z noseparate-code $NO_DT_RELR_LDFLAGS
+#readelf: -S -l --wide
+#target: x86_64-*-linux*
+
+There are 17 section headers, starting at offset 0x101228:
+
+Section Headers:
+ \[Nr\] Name Type Address Off Size ES Flg Lk Inf Al
+ \[ 0\] NULL 0000000000000000 000000 000000 00 0 0 0
+ \[ 1\] .hash HASH 0000000000000120 000120 000018 04 A 2 0 8
+ \[ 2\] .dynsym DYNSYM 0000000000000138 000138 000048 18 A 3 1 8
+ \[ 3\] .dynstr STRTAB 0000000000000180 000180 00000a 00 A 0 0 1
+ \[ 4\] .rela.dyn RELA 0000000000000190 000190 000018 18 A 2 0 8
+ \[ 5\] .plt PROGBITS 00000000000001b0 0001b0 000010 10 AX 0 0 16
+ \[ 6\] .plt.got PROGBITS 00000000000001c0 0001c0 000008 08 AX 0 0 8
+ \[ 7\] .text PROGBITS 00000000000001c8 0001c8 00000c 00 AX 0 0 1
+ \[ 8\] .eh_frame PROGBITS 00000000000001d8 0001d8 00006c 00 A 0 0 8
+ \[ 9\] .init_array INIT_ARRAY 00000000000ffff8 0ffff8 000004 08 WA 0 0 8
+ \[10\] .fini_array FINI_ARRAY 0000000000100000 100000 000100 08 WA 0 0 1048576
+ \[11\] .dynamic DYNAMIC 0000000000100100 100100 000150 10 WA 3 0 8
+ \[12\] .got PROGBITS 0000000000100250 100250 000020 08 WA 0 0 8
+ \[13\] .data PROGBITS 0000000000101000 101000 000100 00 WA 0 0 1
+ \[14\] .symtab SYMTAB 0000000000000000 101100 000078 18 15 3 8
+ \[15\] .strtab STRTAB 0000000000000000 101178 000029 00 0 0 1
+ \[16\] .shstrtab STRTAB 0000000000000000 1011a1 000080 00 0 0 1
+Key to Flags:
+ W \(write\), A \(alloc\), X \(execute\), M \(merge\), S \(strings\), I \(info\),
+ L \(link order\), O \(extra OS processing required\), G \(group\), T \(TLS\),
+ C \(compressed\), x \(unknown\), o \(OS specific\), E \(exclude\),
+ D \(mbind\), l \(large\), p \(processor specific\)
+
+Elf file type is DYN \(Shared object file\)
+Entry point 0x0
+There are 4 program headers, starting at offset 64
+
+Program Headers:
+ Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
+ LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x000244 0x000244 R E 0x1000
+ LOAD 0x0ffff8 0x00000000000ffff8 0x00000000000ffff8 0x001108 0x001108 RW 0x100000
+ DYNAMIC 0x100100 0x0000000000100100 0x0000000000100100 0x000150 0x000150 RW 0x8
+ GNU_RELRO 0x0ffff8 0x00000000000ffff8 0x00000000000ffff8 0x001008 0x001008 R 0x1
+
+ Section to Segment mapping:
+ Segment Sections...
+ 00 .hash .dynsym .dynstr .rela.dyn .plt .plt.got .text .eh_frame
+ 01 .init_array .fini_array .dynamic .got .data
+ 02 .dynamic
+ 03 .init_array .fini_array .dynamic .got
+#pass
projects / binutils-gdb.git / commitdiff