From efb2a7b412c2c78eaf6d3b63f153a749fcde292c Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Tue, 9 Jun 2020 09:32:10 +0930 Subject: [PATCH] PowerPC64: Downgrade ifunc with textrel error to a warning For ppc64 I set flags when recording the dynamic relocation rather than when allocating space. That allows you to distinguish three cases: 1) The dynamic ifunc relocation is in an executable and will always be to an ifunc resolver in the executable. 2) The dynamic ifunc relocation is in a shared library which provides an ifunc resolver, but that may be overridden at runtime to use a resolver in another binary. 3) The dynamic ifunc relocation is not to a locally defined ifunc resolver. Case (3) won't cause a segfault trying to run resolver code that is non-exec on older glibc. I made case (1) an error for ppc64, but since newer glibc ld.so does allow running ifunc resolvers when segments are writable I suppose I should downgrade that to a warning like case (2). * elf64-ppc.c (struct ppc_link_hash_table): Delete maybe_local_ifunc_resolver field. (build_global_entry_stubs_and_plt): Set local_ifunc_resolver in cases where maybe_local_ifunc_resolver was set. (ppc64_elf_relocate_section): Likewise. (ppc64_elf_finish_dynamic_sections): Downgrade ifunc with textrel error to a warning. --- bfd/ChangeLog | 10 ++++++++++ bfd/elf64-ppc.c | 15 +++------------ 2 files changed, 13 insertions(+), 12 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 7765dd36359..146045b0b87 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,13 @@ +2020-06-09 Alan Modra + + * elf64-ppc.c (struct ppc_link_hash_table): Delete + maybe_local_ifunc_resolver field. + (build_global_entry_stubs_and_plt): Set local_ifunc_resolver in + cases where maybe_local_ifunc_resolver was set. + (ppc64_elf_relocate_section): Likewise. + (ppc64_elf_finish_dynamic_sections): Downgrade ifunc with textrel + error to a warning. + 2020-06-08 H.J. Lu * elf-bfd.h (elf_link_hash_entry): Add tlsdesc_plt and diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c index e28546deb54..9868f6a755a 100644 --- a/bfd/elf64-ppc.c +++ b/bfd/elf64-ppc.c @@ -3242,7 +3242,6 @@ struct ppc_link_hash_table /* Whether there exist local gnu indirect function resolvers, referenced by dynamic relocations. */ unsigned int local_ifunc_resolver:1; - unsigned int maybe_local_ifunc_resolver:1; /* Whether plt calls for ELFv2 localentry:0 funcs have been optimized. */ unsigned int has_plt_localentry0:1; @@ -13935,7 +13934,7 @@ build_global_entry_stubs_and_plt (struct elf_link_hash_entry *h, void *inf) + ((ent->plt.offset - PLT_INITIAL_ENTRY_SIZE (htab)) / PLT_ENTRY_SIZE (htab) * sizeof (Elf64_External_Rela))); if (h->type == STT_GNU_IFUNC && is_static_defined (h)) - htab->maybe_local_ifunc_resolver = 1; + htab->local_ifunc_resolver = 1; bfd_elf64_swap_reloca_out (info->output_bfd, &rela, loc); } } @@ -16103,10 +16102,8 @@ ppc64_elf_relocate_section (bfd *output_bfd, if (ifunc) { relgot = htab->elf.irelplt; - if (indx == 0) + if (indx == 0 || is_static_defined (&h->elf)) htab->local_ifunc_resolver = 1; - else if (is_static_defined (&h->elf)) - htab->maybe_local_ifunc_resolver = 1; } else if (indx != 0 || (bfd_link_pic (info) @@ -16635,10 +16632,8 @@ ppc64_elf_relocate_section (bfd *output_bfd, : ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC) { sreloc = htab->elf.irelplt; - if (indx == 0) + if (indx == 0 || is_static_defined (&h->elf)) htab->local_ifunc_resolver = 1; - else if (is_static_defined (&h->elf)) - htab->maybe_local_ifunc_resolver = 1; } if (sreloc == NULL) abort (); @@ -17403,10 +17398,6 @@ ppc64_elf_finish_dynamic_sections (bfd *output_bfd, case DT_TEXTREL: if (htab->local_ifunc_resolver) - info->callbacks->einfo - (_("%X%P: text relocations and GNU indirect " - "functions will result in a segfault at runtime\n")); - else if (htab->maybe_local_ifunc_resolver) info->callbacks->einfo (_("%P: warning: text relocations and GNU indirect " "functions may result in a segfault at runtime\n")); -- 2.30.2