* [PATCH] nios2: Scan dynamic relocations in read-only section
[not found] ` <CAMe9rOpAwzuOdBB=9ZEigmqGVKgApeRB13o3ZGQCpAi4=st0qw@mail.gmail.com>
@ 2020-05-31 13:05 ` H.J. Lu
2020-06-03 15:51 ` Nick Clifton
0 siblings, 1 reply; 2+ messages in thread
From: H.J. Lu @ 2020-05-31 13:05 UTC (permalink / raw)
To: binutils, Sandra Loosemore, Andrew Jenner
On Sat, May 30, 2020 at 11:11:48AM -0700, H.J. Lu wrote:
> On Sat, May 30, 2020 at 10:26 AM Jeff Law <law@redhat.com> wrote:
> >
> >
> > This change:
> >
> > a6dbf402de65fe66f4ec99b56527dfd00d077cb6 is the first bad commit
> > commit a6dbf402de65fe66f4ec99b56527dfd00d077cb6
> > Author: H.J. Lu <hjl.tools@gmail.com>
> > Date: Wed May 27 04:53:54 2020 -0700
> >
> > ld: Add --warn-textrel and obsolete --warn-shared-textrel
> >
> > --warn-shared-textrel and -z text apply to both shared object and PIE.
> > Add --warn-textrel and obsolete --warn-shared-textrel. Consolidate
> > --warn-textrel and -z text/notext/textoff implementation.
> >
> > bfd/
> >
> > PR ld/22909
> > * elflink.c (bfd_elf_final_link): Use bfd_link_textrel_check.
> > Check bfd_link_dll when issue a DT_TEXTREL warning.
> > * elfxx-x86.c (maybe_set_textrel): Likewise.
> > (_bfd_x86_elf_size_dynamic_sections): Likewise.
> >
> > include/
> >
> > PR ld/22909
> > * bfdlink.h (textrel_check_method): New enum.
> > (bfd_link_textrel_check): New.
> > (bfd_link_info): Replace warn_shared_textrel and error_textrel
> > with textrel_check.
> >
> > ld/
> >
> > PR ld/22909
> > * NEWS: Mention --warn-textrel.
> > * ld.texi: Update -z text/notext/textoff. Add --warn-textrel.
> > Remove --warn-shared-textrel.
> > * ldlex.h (option_values): Rename OPTION_WARN_SHARED_TEXTREL to
> > OPTION_WARN_TEXTREL.
> > * lexsup.c (ld_options): Add --warn-textrel. Obsolete
> > --warn-shared-textrel.
> > (parse_args): Updated.
> > (elf_shlib_list_options): Check link_info.textrel_check.
> > * emultempl/elf.em: Updated.
> > * testsuite/ld-elf/pr19539.d: Replace -z notext with
> > --warn-textrel. Expect a warning.
> > * testsuite/ld-i386/warn1.d: Update expected warning.
> >
> > Causes a regression for nios2-linux-gnu :
> >
> > FAIL: ld-elf/pr19539
> >
>
> I saw
>
> FAIL: Common symbol override test
> FAIL: ld-elf/pr19539
> FAIL: DT_TEXTREL in shared lib
> FAIL: DT_TEXTREL map file warning
>
> Last 3 are related. I think it is a bug in the nios2 linker backend:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=26066
>
Add maybe_set_textrel to set DF_TEXTREL by scanning dynamic relocations
in read-only section.
This fixed:
FAIL: ld-elf/pr19539
FAIL: DT_TEXTREL in shared lib
FAIL: DT_TEXTREL map file warning
OK for master?
H.J.
--
PR ld/26066
* elf32-nios2.c (readonly_dynrelocs): New function.
(maybe_set_textrel): Likewise.
(nios2_elf32_size_dynamic_sections): Use maybe_set_textrel to
set DF_TEXTREL.
---
bfd/elf32-nios2.c | 81 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 71 insertions(+), 10 deletions(-)
diff --git a/bfd/elf32-nios2.c b/bfd/elf32-nios2.c
index f0cdd5203a..99f2c476e5 100644
--- a/bfd/elf32-nios2.c
+++ b/bfd/elf32-nios2.c
@@ -5724,6 +5724,63 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, PTR inf)
return TRUE;
}
+/* Find dynamic relocs for H that apply to read-only sections. */
+
+static asection *
+readonly_dynrelocs (struct elf_link_hash_entry *h)
+{
+ struct elf_dyn_relocs *p;
+ struct elf32_nios2_link_hash_entry *eh;
+
+ eh = (struct elf32_nios2_link_hash_entry *) h;
+ for (p = eh->dyn_relocs; p != NULL; p = p->next)
+ {
+ asection *s = p->sec->output_section;
+
+ if (s != NULL && (s->flags & SEC_READONLY) != 0)
+ return p->sec;
+ }
+ return NULL;
+}
+
+/* Set DF_TEXTREL if we find any dynamic relocs that apply to
+ read-only sections. */
+
+static bfd_boolean
+maybe_set_textrel (struct elf_link_hash_entry *h, void *inf)
+{
+ asection *sec;
+
+ if (h->root.type == bfd_link_hash_indirect)
+ return TRUE;
+
+ /* Skip local IFUNC symbols. */
+ if (h->forced_local && h->type == STT_GNU_IFUNC)
+ return TRUE;
+
+ sec = readonly_dynrelocs (h);
+ if (sec != NULL)
+ {
+ struct bfd_link_info *info = (struct bfd_link_info *) inf;
+
+ info->flags |= DF_TEXTREL;
+ /* xgettext:c-format */
+ info->callbacks->minfo (_("%pB: dynamic relocation against `%pT' "
+ "in read-only section `%pA'\n"),
+ sec->owner, h->root.root.string, sec);
+
+ if (bfd_link_textrel_check (info))
+ /* xgettext:c-format */
+ info->callbacks->einfo (_("%P: %pB: warning: relocation against `%s' "
+ "in read-only section `%pA'\n"),
+ sec->owner, h->root.root.string, sec);
+
+ /* Not an error, just cut short the traversal. */
+ return FALSE;
+ }
+ return TRUE;
+}
+
/* Implement elf_backend_size_dynamic_sections:
Set the sizes of the dynamic sections. */
static bfd_boolean
@@ -5796,8 +5853,6 @@ nios2_elf32_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
{
srel = elf_section_data (p->sec)->sreloc;
srel->size += p->count * sizeof (Elf32_External_Rela);
- if ((p->sec->output_section->flags & SEC_READONLY) != 0)
- info->flags |= DF_TEXTREL;
}
}
}
@@ -5946,17 +6001,23 @@ nios2_elf32_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
|| !add_dynamic_entry (DT_JMPREL, 0)))
return FALSE;
- if (relocs
- && (!add_dynamic_entry (DT_RELA, 0)
+ if (relocs)
+ {
+ if (!add_dynamic_entry (DT_RELA, 0)
|| !add_dynamic_entry (DT_RELASZ, 0)
- || !add_dynamic_entry (DT_RELAENT, sizeof (Elf32_External_Rela))))
- return FALSE;
+ || !add_dynamic_entry (DT_RELAENT,
+ sizeof (Elf32_External_Rela)))
+ return FALSE;
- if (!bfd_link_pic (info) && !add_dynamic_entry (DT_NIOS2_GP, 0))
- return FALSE;
+ if ((info->flags & DF_TEXTREL) == 0)
+ elf_link_hash_traverse (&htab->root, maybe_set_textrel, info);
- if ((info->flags & DF_TEXTREL) != 0
- && !add_dynamic_entry (DT_TEXTREL, 0))
+ if ((info->flags & DF_TEXTREL) != 0
+ && !add_dynamic_entry (DT_TEXTREL, 0))
+ return FALSE;
+ }
+
+ if (!bfd_link_pic (info) && !add_dynamic_entry (DT_NIOS2_GP, 0))
return FALSE;
}
#undef add_dynamic_entry
--
2.26.2
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