When performing DISP{16,32} relocations, the eBPF ELF backend linker
needs to convert the relocation from an address into a signed number
of 64-bit words (minus one) to jump.
Because of this unsigned-to-signed conversion, special care needs to
be taken when dividing to ensure the sign bits remain correct.
Otherwise, a false relocation overflow error can be triggered.
bfd/ChangeLog
2020-08-07 David Faust <david.faust@oracle.com>
* elf64-bpf.c (bpf_elf_relocate_section): Ensure signed division for
DISP16 and DISP32 relocations.
ld/ChangeLog
2020-08-07 David Faust <david.faust@oracle.com>
* testsuite/ld-bpf/call-3.s: New file.
* testsuite/ld-bpf/call-3.d: Likewise.
The eBPF ELF backend was not properly recording relocation addends
during installation, nor reading and applying them when performing
the final relocation. This lead to various issues with incorrect
relocations.
These issues are fixed with a new howto special function to install
the relocations, and updates to bpf_elf_relocate_section to read and
use the addends as recorded in the input_bfd.
bfd/ChangeLog
2020-08-05 David Faust <david.faust@oracle.com>
* elf64-bpf.c (bpf_elf_generic_reloc): New function.
(bpf_elf_howto_table): Use it here.
(bpf_elf_relocate_section): Use addends recorded in input_bfd for
instruction and data relocations.
ld/ChangeLog
2020-08-05 David Faust <david.faust@oracle.com>
* testsuite/ld-bpf/call-2.s: New file.
* testsuite/ld-bpf/call-2.d: Likewise.
* testsuite/ld-bpf/reloc-data-be.d: Likewise.
* testsuite/ld-bpf/reloc-data-le.d: Likewise.
* testsuite/ld-bpf/reloc-data.s: Likewise.
* testsuite/ld-bpf/reloc-insn-external-be.d: Likewise.
* testsuite/ld-bpf/reloc-insn-external-le.d: Likewise.
* testsuite/ld-bpf/reloc-insn-external.s: Likewise.
* testsuite/ld-bpf/reloc-insn32-be.d: Likewise.
* testsuite/ld-bpf/reloc-insn32-le.d: Likewise.
* testsuite/ld-bpf/reloc-insn32.s: Likewise.
* testsuite/ld-bpf/reloc-insn64-be.d: Likewise.
* testsuite/ld-bpf/reloc-insn64-le.d: Likewise.
* testsuite/ld-bpf/reloc-insn64.s: Likewise.
As far as I can tell, the following comment is false nowadays.
/* Calls to m-alloc get turned by sed into xm-alloc. */
Remove it, and call xmalloc.
* ldlex.l (yy_create_string_buffer): Use xmalloc rather than malloc.
* lexsup.c (parse_args): Likewise.
(cherry picked from commit ee44c2ac7b3efdfd28c41cd32d7fb935b0582a97)
On aarch64 the first PLT entry is 32 bytes, subsequent entries
are 16 bytes by default but can be 24 bytes with BTI or with
PAC-PLT.
sh_entsize of .plt was set to the PLT entry size, so in some
cases sh_size % sh_entsize != 0, which breaks some tools.
Note that PLT0 (and the TLSDESC stub code which is also in the
PLT) were historically not padded up to meet the sh_size
requirement, but to ensure that PLT stub code is aligned on
cache lines. Similar layout is present on other targets too
which just happens to make sh_size a multiple of sh_entsize and
it is not expected that sh_entsize of .plt is used for anything.
This patch sets sh_entsize of .plt to 0: the section does not
hold a table of fixed-size entries so other values are not
conforming in principle to the ELF spec.
bfd/ChangeLog:
PR ld/26312
* elfnn-aarch64.c (elfNN_aarch64_init_small_plt0_entry): Set sh_entsize
to 0.
(elfNN_aarch64_finish_dynamic_sections): Remove sh_entsize setting.
(cherry picked from commit 4d3bb35620e70d543d438bf21be1307f7ea0f5d0)
Since (%bp)/(%ebp)/(%rbp) are encoded as 0(%bp)/0(%ebp)/0(%rbp), use
disp32/disp16 on 0(%bp)/0(%ebp)/0(%rbp) for {disp32}.
Note: Since there is no disp32 on 0(%bp), use disp16 instead.
PR gas/26305
* config/tc-i386.c (build_modrm_byte): Use disp32/disp16 on
(%bp)/(%ebp)/(%rbp) for {disp32}.
* doc/c-i386.texi: Update {disp32} documentation.
* testsuite/gas/i386/pseudos.s: Add (%bp)/(%ebp) tests.
* testsuite/gas/i386/x86-64-pseudos.s: Add (%ebp)/(%rbp) tests.
* testsuite/gas/i386/pseudos.d: Updated.
* testsuite/gas/i386/x86-64-pseudos.d: Likewise.
(cherry picked from commit 1a02d6b0ff80048df106cbb776a550278f8c9d9c)
Fix a regression from commit a87e1817a4 ("Have the linker fail if any
attempt to link in an executable is made.") and do not reject ET_EXEC
input supplied with the `--just-symbols' option. Such use is legitimate
as the file requested is not actually linked and only the symbols are
extracted. Furthermore it is often the most useful application, as
already observed in our documentation for the option, where it allows
"to refer symbolically to absolute locations of memory defined in other
programs."
Provide a set of tests for the use of ET_EXEC with `--just-symbols'.
These are excluded however for SH/PE targets because they complain if a
section's VMA is 0:
ld: zero vma section reloc detected: `.text' #0 f=32795
ld: zero vma section reloc detected: `.data' #1 f=291
and for x86_64/PE targets because they seem to hardwire the VMA:
100000000 12000000 01000000 00000000 00000000 ................
ld/
PR ld/26288
* ldelf.c (ldelf_after_open): Do not reject ET_EXEC input
supplied with `--just-symbols'.
* testsuite/ld-misc/just-symbols.exp: New test script.
* testsuite/ld-misc/just-symbols-1.dd: New test dump.
* testsuite/ld-misc/just-symbols.ld: New test linker script.
* testsuite/ld-misc/just-symbols-0.s: New test source.
* testsuite/ld-misc/just-symbols-1.s: New test source.
(cherry picked from commit 97c79e2174fbb0dda16850fa5366592e93d31cb9)
Revert commit a3fc941881 ("Stop the linker from accepting executable
ELF files as inputs to other links."), which has been made obsolete by
commit a87e1817a4 ("Have the linker fail if any attempt to link in an
executable is made."). An earlier check triggers added with the latter
commit making the piece of code removed dead.
ld/
PR ld/26288
Revert:
PR 26047
* ldelf.c (ldelf_after_open): Fail if attempting to link one
executable into another.
(cherry picked from commit b5dd7120f6bcbd1fe650b8839a53b2bd423fbf60)
We change the previous definition in the IR object to undefweak only
after all LTO symbols have been read.
include/
PR ld/26262
PR ld/26267
* bfdlink.h (bfd_link_info): Add lto_all_symbols_read.
ld/
PR ld/26262
PR ld/26267
* ldlang.c (lang_process): Set lto_all_symbols_read after all
LTO IR symbols have been read.
* plugin.c (plugin_notice): Override the IR definition only if
all LTO IR symbols have been read or the new definition is
non-weak and the the IR definition is weak
* testsuite/ld-plugin/lto.exp: Run PR ld/26262 and ld/26267
tests.
* testsuite/ld-plugin/pr26262a.c: New file.
* testsuite/ld-plugin/pr26262b.c: Likewise.
* testsuite/ld-plugin/pr26262c.c: Likewise.
* testsuite/ld-plugin/pr26267.err: Likewise.
* testsuite/ld-plugin/pr26267a.c: Likewise.
* testsuite/ld-plugin/pr26267b.c: Likewise.
* testsuite/ld-plugin/pr26267c.c: Likewise.
(cherry picked from commit 0e6a3f07f50723d1831291492b96fdf74bcbdc11)
Update and run PR gas/26263 linker tests for all x86 ELF targets to
accept any program header layout.
PR gas/26263
* testsuite/ld-i386/pr26263.d: Updated.
* testsuite/ld-x86-64/pr26263.d: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run gas/26263 test for all ELF
targets.
(cherry picked from commit 98b3697bcdedb92739d8feb9b881efdd70fd40d3)
This patch better supports mixing of power10 and non-power10 code,
as might be seen in a cpu-optimized library using ifuncs to select
functions optimized for a given cpu. Using -Wl,--no-power10-stubs
isn't that good in this situation since non-power10 notoc stubs are
slower and larger than the power10 variants, which you'd like to use
on power10 code paths.
With this change, power10 pc-relative code that makes calls marked
@notoc uses power10 stubs if stubs are necessary, and other calls use
non-power10 instructions in stubs. This will mean that if gcc is
generating code for -mcpu=power10 but with pc-rel disabled then you'll
get the older stubs even on power10 (unless you force with
-Wl,--power10-stubs). That shouldn't be too big a problem: stubs that
use r2 are reasonable. It's just the ones that set up addressing
using "mflr 12; bcl 20,31,.+4; mflr 11; mtlr 12" that should be
avoided if possible.
bfd/
* elf64-ppc.c (struct ppc_link_hash_table): Add has_power10_relocs.
(select_alt_stub): New function.
(ppc_get_stub_entry): Use it here.
(ppc64_elf_check_relocs): Set had_power10_relocs rather than
power10_stubs.
(ppc64_elf_size_stubs): Clear power10_stubs here instead. Don't
merge notoc stubs with other varieties when power10_stubs is "auto".
Instead dup the stub hash table entry.
(plt_stub_size, ppc_build_one_stub, ppc_size_one_stub): Adjust
tests of power10_stubs.
ld/
* emultempl/ppc64elf.em (power10-stubs): Accept optional "auto" arg.
* ld.texi (power10-stubs): Update.
* testsuite/ld-powerpc/callstub-1.d: Force --power10-stubs.
* testsuite/ld-powerpc/callstub-2.d: Relax branch offset comparison.
* testsuite/ld-powerpc/callstub-4.d: New test.
* testsuite/ld-powerpc/notoc.d: Force --no-power10-stubs.
* testsuite/ld-powerpc/notoc3.d,
* testsuite/ld-powerpc/notoc3.s,
* testsuite/ld-powerpc/notoc3.wf: New test.
* testsuite/ld-powerpc/powerpc.exp: Run new tests. Pass
--no-power10-stubs for notoc link.
(cherry picked from commit e10a07b32dc1faed25b5bbcbbc47d68e2ff537b9)
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