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Revert D125410 "[ELF] Align the end of PT_GNU_RELRO to max-page-size instead of common-page-size"

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This reverts commit ebdb9d635a077274e38baa8584f5b0e631b4b1d3.

Changing p_memsz is insufficient and may make PT_GNU_RELRO extend beyond the
PT_LOAD.
This commit is contained in:
Fangrui Song 2022-05-12 20:41:22 -07:00
parent 8050ba6678
commit 2ac8ce5d56
4 changed files with 7 additions and 10 deletions
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9
lld/ELF/Writer.cpp
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@ -2638,10 +2638,11 @@ template <class ELFT> void Writer<ELFT>::setPhdrs(Partition &part) {
if (p->p_type == PT_GNU_RELRO) {
p->p_align = 1;
// musl/glibc/FreeBSD ld.so rounds the size down, so we need to round up
// to protect the last page.
p->p_memsz =
alignTo(p->p_offset + p->p_memsz, config->maxPageSize) - p->p_offset;
// musl/glibc ld.so rounds the size down, so we need to round up
// to protect the last page. This is a no-op on FreeBSD which always
// rounds up.
p->p_memsz = alignTo(p->p_offset + p->p_memsz, config->commonPageSize) -
p->p_offset;
}
}
}

4
lld/docs/ReleaseNotes.rst
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@ -29,10 +29,6 @@ ELF Improvements
* ``-z pack-relative-relocs`` is now available to support ``DT_RELR`` for glibc 2.36+.
(`D120701 <https://reviews.llvm.org/D120701>`_)
* ``--no-fortran-common`` (pre 12.0.0 behavior) is now the default.
* The end of ``PT_GNU_RELRO`` is now aligned by ``max-page-size`` instead of ``common-page-size``.
This matches GNU ld from 2.39 onwards. If the system page size is larger than ``common-page-size``,
the previous choice may make a partial page not protected by RELRO.
(`D125410 <https://reviews.llvm.org/D125410>`_)
Breaking changes
----------------

2
lld/test/ELF/aarch64-relro.s
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@ -8,7 +8,7 @@
# CHECK-NEXT: VirtualAddress: 0x220190
# CHECK-NEXT: PhysicalAddress:
# CHECK-NEXT: FileSize:
# CHECK-NEXT: MemSize: 65136
# CHECK-NEXT: MemSize: 3696
.section .data.rel.ro,"aw",%progbits
.byte 1

2
lld/test/ELF/basic-ppc64.s
View File

@ -336,7 +336,7 @@
// CHECK-NEXT: VirtualAddress: 0x20238
// CHECK-NEXT: PhysicalAddress: 0x20238
// CHECK-NEXT: FileSize: 96
// CHECK-NEXT: MemSize: 64968
// CHECK-NEXT: MemSize: 3528
// CHECK-NEXT: Flags [ (0x4)
// CHECK-NEXT: PF_R (0x4)
// CHECK-NEXT: ]