82442adfc0
Many -static/-no-pie/-shared/-pie applications linked against glibc or musl
should work with this patch. This also helps FreeBSD PowerPC64 to migrate
their lib32 (PR40888).
* Fix default image base and max page size.
* Support new-style Secure PLT (see below). Old-style BSS PLT is not
implemented, so it is not suitable for FreeBSD rtld now because it doesn't
support Secure PLT yet.
* Support more initial relocation types:
R_PPC_ADDR32, R_PPC_REL16*, R_PPC_LOCAL24PC, R_PPC_PLTREL24, and R_PPC_GOT16.
The addend of R_PPC_PLTREL24 is special: it decides the call stub PLT type
but it should be ignored for the computation of target symbol VA.
* Support GNU ifunc
* Support .glink used for lazy PLT resolution in glibc
* Add a new thunk type: PPC32PltCallStub that is similar to PPC64PltCallStub.
It is used by R_PPC_REL24 and R_PPC_PLTREL24.
A PLT stub used in -fPIE/-fPIC usually loads an address relative to
.got2+0x8000 (-fpie/-fpic code uses _GLOBAL_OFFSET_TABLE_ relative
addresses).
Two .got2 sections in two object files have different addresses, thus a PLT stub
can't be shared by two object files. To handle this incompatibility,
change the parameters of Thunk::isCompatibleWith to
`const InputSection &, const Relocation &`.
PowerPC psABI specified an old-style .plt (BSS PLT) that is both
writable and executable. Linkers don't make separate RW- and RWE segments,
which causes all initially writable memory (think .data) executable.
This is a big security concern so a new PLT scheme (secure PLT) was developed to
address the security issue.
TLS will be implemented in D62940.
glibc older than ~2012 requires .rela.dyn to include .rela.plt, it can
not handle the DT_RELA+DT_RELASZ == DT_JMPREL case correctly. A hack
(not included in this patch) in LinkerScript.cpp addOrphanSections() to
work around the issue:
if (Config->EMachine == EM_PPC) {
// Older glibc assumes .rela.dyn includes .rela.plt
Add(In.RelaDyn);
if (In.RelaPlt->isLive() && !In.RelaPlt->Parent)
In.RelaDyn->getParent()->addSection(In.RelaPlt);
}
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D62464
llvm-svn: 362721
|
||
|---|---|---|
| .. | ||
| Arch | ||
| AArch64ErrataFix.cpp | ||
| AArch64ErrataFix.h | ||
| CMakeLists.txt | ||
| CallGraphSort.cpp | ||
| CallGraphSort.h | ||
| Config.h | ||
| DWARF.cpp | ||
| DWARF.h | ||
| Driver.cpp | ||
| Driver.h | ||
| DriverUtils.cpp | ||
| EhFrame.cpp | ||
| EhFrame.h | ||
| ICF.cpp | ||
| ICF.h | ||
| InputFiles.cpp | ||
| InputFiles.h | ||
| InputSection.cpp | ||
| InputSection.h | ||
| LTO.cpp | ||
| LTO.h | ||
| LinkerScript.cpp | ||
| LinkerScript.h | ||
| MapFile.cpp | ||
| MapFile.h | ||
| MarkLive.cpp | ||
| MarkLive.h | ||
| Options.td | ||
| OutputSections.cpp | ||
| OutputSections.h | ||
| README.md | ||
| Relocations.cpp | ||
| Relocations.h | ||
| ScriptLexer.cpp | ||
| ScriptLexer.h | ||
| ScriptParser.cpp | ||
| ScriptParser.h | ||
| SymbolTable.cpp | ||
| SymbolTable.h | ||
| Symbols.cpp | ||
| Symbols.h | ||
| SyntheticSections.cpp | ||
| SyntheticSections.h | ||
| Target.cpp | ||
| Target.h | ||
| Thunks.cpp | ||
| Thunks.h | ||
| Writer.cpp | ||
| Writer.h | ||
README.md
See docs/NewLLD.rst