SHF_GNU_MBIND requires ELFOSABI_GNU

When SHF_GNU_MBIND was added in the SHF_LOOS to SHF_HIOS range, it
should have required ELFOSABI_GNU since these flags are already in use
by other OSes.  HPUX SHF_HP_TLS in fact has the same value.  That
means no place in binutils should test SHF_GNU_MBIND without first
checking OSABI, and SHF_GNU_MBIND should not be set without also
setting OSABI.  At least, that's the ideal, but the patch accepts
SHF_GNU_MBIND on ELFOSABI_NONE object files since gas didn't always
set OSABI.  However, to reinforce the fact that SHF_GNU_MBIND isn't
proper without a non-zero OSABI, readelf will display the flag as
LOOS+0 if OSABI isn't set.

The clash with SHF_HP_TLS means that hppa64-linux either has that flag
on .tbss sections or supports GNU_MBIND, not both.  (hppa64-linux
users, if there are any, may have noticed that GNU ld since 2017
mysteriously aligned their .tbss sections to a 4k boundary.  That was
one consequence of SHF_HP_TLS being blindly interpreted as
SHF_GNU_MBIND.)  Since it seems that binutils, gdb, gcc, glibc, and
the linux kernel don't care about SHF_HP_TLS I took that flag out of
.tbss for hppa64-linux.

bfd/
	* elf-bfd.h (enum elf_gnu_osabi): Add elf_gnu_osabi_mbind.
	* elf.c (_bfd_elf_make_section_from_shdr): Set elf_gnu_osabi_mbind.
	(get_program_header_size): Formatting.  Only test SH_GNU_MBIND
	when elf_gnu_osabi_mbind is set.
	(_bfd_elf_map_sections_to_segments): Likewise.
	(_bfd_elf_init_private_section_data): Likewise.
	(_bfd_elf_final_write_processing): Update comment.
	* elf64-hppa.c (elf64_hppa_special_sections): Move .tbss entry.
	(elf_backend_special_sections): Define without .tbss for linux.
binutils/
	* readelf.c (get_parisc_segment_type): Split off hpux entries..
	(get_ia64_segment_type): ..and these..
	(get_hpux_segment_type): ..to here.
	(get_segment_type): Condition GNU_MBIND on osabi.  Use
	get_hpux_segment_type.
	(get_symbol_binding): Do not print UNIQUE for ELFOSABI_NONE.
	(get_symbol_type): Do not print IFUNC for ELFOSABI_NONE.
gas/
	* config/obj-elf.c (obj_elf_change_section): Don't emit a fatal
	error for non-SHF_ALLOC SHF_GNU_MBIND here.
	(obj_elf_parse_section_letters): Return SHF_GNU_MBIND in new
	gnu_attr param.
	(obj_elf_section): Adjust obj_elf_parse_section_letters call.
	Formatting.  Set SHF_GNU_MBIND and elf_osabi from gnu_attr.
	Emit normal error for non-SHF_ALLOC SHF_GNU_MBIND and wrong osabi.
	(obj_elf_type): Set elf_osabi for ifunc.
	* testsuite/gas/elf/section12a.d: xfail msp430 and hpux.
	* testsuite/gas/elf/section12b.d: Likewise.
	* testsuite/gas/elf/section13.d: Likewise.
	* testsuite/gas/elf/section13.l: Adjust expected error.
ld/
	* emultempl/elf32.em (gld${EMULATION_NAME}_place_orphan): Condition
	SHF_GNU_MBIND on osabi.  Set output elf_gnu_osabi_mbind.

1 files changed, 48 insertions, 32 deletions

diff --git a/bfd/elf.c b/bfd/elf.c
index 55bb091..1c77a79 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -1067,6 +1067,19 @@ _bfd_elf_make_section_from_shdr (bfd *abfd,
   if ((hdr->sh_flags & SHF_EXCLUDE) != 0)
     flags |= SEC_EXCLUDE;
 
+  switch (elf_elfheader (abfd)->e_ident[EI_OSABI])
+    {
+      /* FIXME: We should not recognize SHF_GNU_MBIND for ELFOSABI_NONE,
+	 but binutils as of 2019-07-23 did not set the EI_OSABI header
+	 byte.  */
+    case ELFOSABI_NONE:
+    case ELFOSABI_GNU:
+    case ELFOSABI_FREEBSD:
+      if ((hdr->sh_flags & SHF_GNU_MBIND) != 0)
+	elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_mbind;
+      break;
+    }
+
   if ((flags & SEC_ALLOC) == 0)
     {
       /* The debugging sections appear to be recognized only by name,
@@ -4425,31 +4438,32 @@ get_program_header_size (bfd *abfd, struct bfd_link_info *info)
 
   bed = get_elf_backend_data (abfd);
 
- if ((abfd->flags & D_PAGED) != 0)
-   {
-     /* Add a PT_GNU_MBIND segment for each mbind section.  */
-     unsigned int page_align_power = bfd_log2 (bed->commonpagesize);
-     for (s = abfd->sections; s != NULL; s = s->next)
-       if (elf_section_flags (s) & SHF_GNU_MBIND)
-	 {
-	   if (elf_section_data (s)->this_hdr.sh_info
-	       > PT_GNU_MBIND_NUM)
-	     {
-	       _bfd_error_handler
-		 /* xgettext:c-format */
-		 (_("%pB: GNU_MBIN section `%pA' has invalid sh_info field: %d"),
-		     abfd, s, elf_section_data (s)->this_hdr.sh_info);
-	       continue;
-	     }
-	   /* Align mbind section to page size.  */
-	   if (s->alignment_power < page_align_power)
-	     s->alignment_power = page_align_power;
-	   segs ++;
-	 }
-   }
-
- /* Let the backend count up any program headers it might need.  */
- if (bed->elf_backend_additional_program_headers)
+  if ((abfd->flags & D_PAGED) != 0
+      && (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_mbind) != 0)
+    {
+      /* Add a PT_GNU_MBIND segment for each mbind section.  */
+      unsigned int page_align_power = bfd_log2 (bed->commonpagesize);
+      for (s = abfd->sections; s != NULL; s = s->next)
+	if (elf_section_flags (s) & SHF_GNU_MBIND)
+	  {
+	    if (elf_section_data (s)->this_hdr.sh_info > PT_GNU_MBIND_NUM)
+	      {
+		_bfd_error_handler
+		  /* xgettext:c-format */
+		  (_("%pB: GNU_MBIND section `%pA' has invalid "
+		     "sh_info field: %d"),
+		   abfd, s, elf_section_data (s)->this_hdr.sh_info);
+		continue;
+	      }
+	    /* Align mbind section to page size.  */
+	    if (s->alignment_power < page_align_power)
+	      s->alignment_power = page_align_power;
+	    segs ++;
+	  }
+    }
+
+  /* Let the backend count up any program headers it might need.  */
+  if (bed->elf_backend_additional_program_headers)
     {
       int a;
 
@@ -5045,11 +5059,12 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info)
 	  pm = &m->next;
 	}
 
-      if (first_mbind && (abfd->flags & D_PAGED) != 0)
+      if (first_mbind
+	  && (abfd->flags & D_PAGED) != 0
+	  && (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_mbind) != 0)
 	for (s = first_mbind; s != NULL; s = s->next)
 	  if ((elf_section_flags (s) & SHF_GNU_MBIND) != 0
-	      && (elf_section_data (s)->this_hdr.sh_info
-		  <= PT_GNU_MBIND_NUM))
+	      && elf_section_data (s)->this_hdr.sh_info <= PT_GNU_MBIND_NUM)
 	    {
 	      /* Mandated PF_R.  */
 	      unsigned long p_flags = PF_R;
@@ -7665,7 +7680,8 @@ _bfd_elf_init_private_section_data (bfd *ibfd,
 			       & (SHF_MASKOS | SHF_MASKPROC));
 
   /* Copy sh_info from input for mbind section.  */
-  if (elf_section_flags (isec) & SHF_GNU_MBIND)
+  if ((elf_tdata (ibfd)->has_gnu_osabi & elf_gnu_osabi_mbind) != 0
+      && elf_section_flags (isec) & SHF_GNU_MBIND)
     elf_section_data (osec)->this_hdr.sh_info
       = elf_section_data (isec)->this_hdr.sh_info;
 
@@ -12118,9 +12134,9 @@ _bfd_elf_final_write_processing (bfd *abfd,
   if (i_ehdrp->e_ident[EI_OSABI] == ELFOSABI_NONE)
     i_ehdrp->e_ident[EI_OSABI] = get_elf_backend_data (abfd)->elf_osabi;
 
-  /* To make things simpler for the loader on Linux systems we set the
-     osabi field to ELFOSABI_GNU if the binary contains symbols of
-     the STT_GNU_IFUNC type or STB_GNU_UNIQUE binding.  */
+  /* Set the osabi field to ELFOSABI_GNU if the binary contains
+     SHF_GNU_MBIND sections or symbols of STT_GNU_IFUNC type or
+     STB_GNU_UNIQUE binding.  */
   if (i_ehdrp->e_ident[EI_OSABI] == ELFOSABI_NONE
       && elf_tdata (abfd)->has_gnu_osabi)
     i_ehdrp->e_ident[EI_OSABI] = ELFOSABI_GNU;