diff options
| author | Fangrui Song <i@maskray.me> | 2022-05-12 21:03:12 +0300 |
|---|---|---|
| committer | Fangrui Song <i@maskray.me> | 2022-05-12 21:03:12 +0300 |
| commit | ebdb9d635a077274e38baa8584f5b0e631b4b1d3 (patch) | |
| tree | 48ae88185cc7454eba9de4afd5e10bf6f6065bf0 /lld | |
| parent | 9f732af583c0dba58847b753a87cc5432ec33f09 (diff) | |
[ELF] Align the end of PT_GNU_RELRO to max-page-size instead of common-page-size
We picked common-page-size to match GNU ld. Recently, the resolution to GNU ld
https://sourceware.org/bugzilla/show_bug.cgi?id=28824 (milestone: 2.39) switched
to max-page-size so that the last page can be protected by RELRO in case the
system page size is larger than common-page-size.
Thanks to our two RW PT_LOAD scheme (D58892), switching to max-page-size does
not change file size (while GNU ld's scheme may increase file size).
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D125410
Diffstat (limited to 'lld')
| -rw-r--r-- | lld/ELF/Writer.cpp | 9 | ||||
| -rw-r--r-- | lld/docs/ReleaseNotes.rst | 4 | ||||
| -rw-r--r-- | lld/test/ELF/aarch64-relro.s | 2 | ||||
| -rw-r--r-- | lld/test/ELF/basic-ppc64.s | 2 |
4 files changed, 10 insertions, 7 deletions
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp index 649958b74798..0f53b7f488bd 100644 --- a/lld/ELF/Writer.cpp +++ b/lld/ELF/Writer.cpp @@ -2638,11 +2638,10 @@ template <class ELFT> void Writer<ELFT>::setPhdrs(Partition &part) { if (p->p_type == PT_GNU_RELRO) { p->p_align = 1; - // 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; + // 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; } } } diff --git a/lld/docs/ReleaseNotes.rst b/lld/docs/ReleaseNotes.rst index b3751e53db55..645721fbb803 100644 --- a/lld/docs/ReleaseNotes.rst +++ b/lld/docs/ReleaseNotes.rst @@ -29,6 +29,10 @@ 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 ---------------- diff --git a/lld/test/ELF/aarch64-relro.s b/lld/test/ELF/aarch64-relro.s index 4047382c8aa1..4223156df996 100644 --- a/lld/test/ELF/aarch64-relro.s +++ b/lld/test/ELF/aarch64-relro.s @@ -8,7 +8,7 @@ # CHECK-NEXT: VirtualAddress: 0x220190 # CHECK-NEXT: PhysicalAddress: # CHECK-NEXT: FileSize: -# CHECK-NEXT: MemSize: 3696 +# CHECK-NEXT: MemSize: 65136 .section .data.rel.ro,"aw",%progbits .byte 1 diff --git a/lld/test/ELF/basic-ppc64.s b/lld/test/ELF/basic-ppc64.s index 4032ceca614f..b3740230c41e 100644 --- a/lld/test/ELF/basic-ppc64.s +++ b/lld/test/ELF/basic-ppc64.s @@ -336,7 +336,7 @@ // CHECK-NEXT: VirtualAddress: 0x20238 // CHECK-NEXT: PhysicalAddress: 0x20238 // CHECK-NEXT: FileSize: 96 -// CHECK-NEXT: MemSize: 3528 +// CHECK-NEXT: MemSize: 64968 // CHECK-NEXT: Flags [ (0x4) // CHECK-NEXT: PF_R (0x4) // CHECK-NEXT: ] |