Add ELF_DYNAMIC_AFTER_RELOC to allow target specific processing after
relocation.
For x86-64, add
#define DT_X86_64_PLT (DT_LOPROC + 0)
#define DT_X86_64_PLTSZ (DT_LOPROC + 1)
#define DT_X86_64_PLTENT (DT_LOPROC + 3)
1. DT_X86_64_PLT: The address of the procedure linkage table.
2. DT_X86_64_PLTSZ: The total size, in bytes, of the procedure linkage
table.
3. DT_X86_64_PLTENT: The size, in bytes, of a procedure linkage table
entry.
With the r_addend field of the R_X86_64_JUMP_SLOT relocation set to the
memory offset of the indirect branch instruction.
Define ELF_DYNAMIC_AFTER_RELOC for x86-64 to rewrite the PLT section
with direct branch after relocation when the lazy binding is disabled.
PLT rewrite is disabled by default since SELinux may disallow modifying
code pages and ld.so can't detect it in all cases. Use
$ export GLIBC_TUNABLES=glibc.cpu.plt_rewrite=1
to enable PLT rewrite with 32-bit direct jump at run-time or
$ export GLIBC_TUNABLES=glibc.cpu.plt_rewrite=2
to enable PLT rewrite with 32-bit direct jump and on APX processors with
64-bit absolute jump at run-time.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The need to maintain elf/elf.h and scripts/glibcelf.py in parallel
results in a backporting hazard: they need to be kept in sync to
avoid elf/tst-glibcelf consistency check failures. glibcelf (unlike
tst-glibcelf) does not use the C implementation to extract constants.
This applies the additional glibcpp syntax checks to <elf.h>.
This changereplaces the types derived from Python enum types with
custom types _TypedConstant, _IntConstant, and _FlagConstant. These
types have fewer safeguards, but this also allows incremental
construction and greater flexibility for grouping constants among
the types. Architectures-specific named constants are now added
as members into their superclasses (but value-based lookup is
still restricted to generic constants only).
Consequently, check_duplicates in elf/tst-glibcelf has been adjusted
to accept differently-named constants of the same value if their
subtypes are distinct. The ordering check for named constants
has been dropped because they are no longer strictly ordered.
Further test adjustments: Some of the type names are different.
The new types do not support iteration (because it is unclear
whether iteration should cover the all named values (including
architecture-specific constants), or only the generic named values),
so elf/tst-glibcelf now uses by_name explicit (to get all constants).
PF_HP_SBP and PF_PARISC_SBP are now of distinct types (PfHP and
PfPARISC), so they are how both present on the Python side. EM_NUM
and PT_NUM are filtered (which was an oversight in the old
conversion).
The new version of glibcelf should also be compatible with earlier
Python versions because it no longer depends on the enum module and its
advanced features.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
ELF and GNU hashes can now be computed using the elf_hash and
gnu_hash functions.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Hopefully, this will lead to tests that are easier to maintain. The
current approach of parsing readelf -W output using regular expressions
is not necessarily easier than parsing the ELF data directly.
This module is still somewhat incomplete (e.g., coverage of relocation
types and versioning information is missing), but it is sufficient to
perform basic symbol analysis or program header analysis.
The EM_* mapping for architecture-specific constant classes (e.g.,
SttX86_64) is not yet implemented. The classes are defined for the
benefit of elf/tst-glibcelf.py.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
