From f26a32876ba49b2d5537beccea2a38bc544e9732 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Thu, 11 Jul 2019 22:08:39 +0930 Subject: Dynamic TLS section symbols It is possible to create shared libraries on PowerPC using -ftls-model=inital-exec or -ftls-model=local-exec. The first is half reasonable, getting you a shared library that can't be dlopen'd but otherwise is reasonable. The second is quite bad. Not only do you lose being able to dlopen, the library also has dynamic text relocations. Worse, the TPREL16_LO, TPREL16_HA and other TPREL16 dynamic relocs emitted were wrong, resulting in wrong values being applied by ld.so. Using the first TLS section symbol in dynamic relocations for local TLS symbols doesn't work. It's wrong because TLS symbols used by TLS relocs have values relative to the TLS segment, whereas the TLS section symbols are addresses. This patch instead uses a symbol index of zero which is used elsewhere by PowerPC on dynamic TLS relocs. It's not strictly ABI compliant to use a non-TLS symbol with TLS relocs but symbol index zero can be interpreted as "no symbol". Not using the first TLS section symbol means it doesn't need to be dynamic. The patch also fixes a further problem with PowerPC32 dynamic TPREL16* relocs, which shouldn't have the symbol value in the addend as we do for non-TLS symbols. bfd/ * elflink.c (_bfd_elf_omit_section_dynsym_default): Don't keep tls_sec. (_bfd_elf_init_1_index_section): Prefer not using TLS sections. (_bfd_elf_init_2_index_sections): Likewise. * elf64-ppc.c (ppc64_elf_relocate_section): When emitting dynamic relocations for local TLS symbols, use STN_UNDEF as the relocation symbol. * elf32-ppc.c (ppc_elf_relocate_section): Likewise, and don't leave TLS symbol value in the addend. ld/ * testsuite/ld-powerpc/tlsso.r: Update. * testsuite/ld-powerpc/tlsso32.g: Update. * testsuite/ld-powerpc/tlsso32.r: Update. * testsuite/ld-powerpc/tlstocso.r: Update. * testsuite/ld-cris/tls-dso-dtpoffd2.d: Update. * testsuite/ld-cris/tls-dso-dtpoffd4.d: Update. * testsuite/ld-cris/tls-dso-tpoffgotcomm1.d: Update. * testsuite/ld-cris/tls-gd-1.d: Update. * testsuite/ld-cris/tls-gd-1h.d: Update. * testsuite/ld-cris/tls-gd-2.d: Update. * testsuite/ld-cris/tls-gd-2h.d: Update. * testsuite/ld-cris/tls-ie-10.d: Update. * testsuite/ld-cris/tls-ie-11.d: Update. * testsuite/ld-cris/tls-ie-8.d: Update. * testsuite/ld-cris/tls-ie-9.d: Update. * testsuite/ld-cris/tls-js1.d: Update. * testsuite/ld-cris/tls-ld-4.d: Update. * testsuite/ld-cris/tls-ld-5.d: Update. * testsuite/ld-cris/tls-ld-6.d: Update. * testsuite/ld-cris/tls-ld-7.d: Update. * testsuite/ld-cris/tls-ldgd-14.d: Update. * testsuite/ld-cris/tls-ldgd-15.d: Update. * testsuite/ld-cris/tls-ldgdx-14.d: Update. * testsuite/ld-cris/tls-ldgdx-15.d: Update. * testsuite/ld-cris/tls-local-54.d: Update. * testsuite/ld-cris/tls-local-60.d: Update. * testsuite/ld-cris/tls-local-61.d: Update. * testsuite/ld-cris/tls-local-63.d: Update. * testsuite/ld-cris/tls-local-64.d: Update. * testsuite/ld-cris/tls-ok-30.d: Update. * testsuite/ld-cris/tls-ok-32.d: Update. * testsuite/ld-cris/tls-ok-34.d: Update. * testsuite/ld-mips-elf/tls-multi-got-1.got: Update. * testsuite/ld-mips-elf/tls-multi-got-1.r: Update. * testsuite/ld-mips-elf/tlsdyn-pie-o32.d: Update. * testsuite/ld-mips-elf/tlsdyn-pie-o32.got: Update. * testsuite/ld-mips-elf/tlslib-o32-hidden.got: Update. * testsuite/ld-mips-elf/tlslib-o32-ver.got: Update. * testsuite/ld-mips-elf/tlslib-o32.got: Update. * testsuite/ld-s390/tlspic.rd: Update. * testsuite/ld-s390/tlspic_64.rd: Update. * testsuite/ld-sparc/tlssunnopic32.rd: Update. * testsuite/ld-sparc/tlssunnopic64.rd: Update. * testsuite/ld-sparc/tlssunpic32.rd: Update. * testsuite/ld-sparc/tlssunpic64.rd: Update. --- bfd/ChangeLog | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'bfd/ChangeLog') diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 7daec6b..b41c059 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,15 @@ +2019-07-13 Alan Modra + + * elflink.c (_bfd_elf_omit_section_dynsym_default): Don't keep + tls_sec. + (_bfd_elf_init_1_index_section): Prefer not using TLS sections. + (_bfd_elf_init_2_index_sections): Likewise. + * elf64-ppc.c (ppc64_elf_relocate_section): When emitting dynamic + relocations for local TLS symbols, use STN_UNDEF as the relocation + symbol. + * elf32-ppc.c (ppc_elf_relocate_section): Likewise, and don't + leave TLS symbol value in the addend. + 2019-07-08 Alan Modra PR 24785 -- cgit v1.1