commit b80eed39e2e813c37cffcb873dc4fdd03381383c

Author: Alan Modra <amodra@gmail.com>

Date:   Fri Mar 7 10:14:30 2014 +1030

    Better overflow checking for powerpc64 relocations

    R_PPC64_ADDR16 is used in three contexts:

    - .short data relocation

    - 16-bit signed insn fields, eg. addi

    - 16-bit unsigned insn fields, eg. ori

    In the first case we want to allow both signed and unsigned 16-bit

    values, the latter two ought to error if the field exceeds the range

    of values allowed for 16-bit signed and unsigned integers

    respectively.  These conflicting requirements meant that ld had to

    choose the least restrictive overflow checks, and thus it is possible

    to construct testcases where an addi field overflows but is not

    reported by ld.  Many relocations dealing with 16-bit insn fields have

    this problem.  What's more, some relocations that are only ever used

    for signed fields of instructions woodenly copied the lax overflow

    checking of R_PPC64_ADDR16.

    bfd/

            * elf64-ppc.c (ppc64_elf_howto_raw): Use complain_overflow_signed

            for R_PPC64_ADDR14, R_PPC64_ADDR14_BRTAKEN, R_PPC64_ADDR14_BRNTAKEN,

            R_PPC64_SECTOFF, R_PPC64_ADDR16_DS, R_PPC64_SECTOFF_DS,

            R_PPC64_REL16 entries.  Use complain_overflow_dont for R_PPC64_TOC.

            (ppc64_elf_relocate_section): Modify overflow test for 16-bit

            fields in instructions to signed/unsigned according to whether

            the field takes a signed or unsigned value.

    gold/

            * powerpc.cc (Powerpc_relocate_functions::Overflow_check): Add

            CHECK_UNSIGNED, CHECK_LOW_INSN, CHECK_HIGH_INSN.

            (Powerpc_relocate_functions::has_overflow_unsigned): New function.

            (Powerpc_relocate_functions::has_overflow_bitfield,

            overflowed): Use the above.

            (Target_powerpc::Relocate::relocate): Correct overflow checking

            for a number of relocations.  Modify overflow test for 16-bit

            fields in instructions to signed/unsigned according to whether

            the field takes a signed or unsigned value.

### a/bfd/ChangeLog

### b/bfd/ChangeLog

## -1,3 +1,13 @@

+2014-03-08  Alan Modra  <amodra@gmail.com>

+

+	* elf64-ppc.c (ppc64_elf_howto_raw): Use complain_overflow_signed

+	for R_PPC64_ADDR14, R_PPC64_ADDR14_BRTAKEN, R_PPC64_ADDR14_BRNTAKEN,

+	R_PPC64_SECTOFF, R_PPC64_ADDR16_DS, R_PPC64_SECTOFF_DS,

+	R_PPC64_REL16 entries.  Use complain_overflow_dont for R_PPC64_TOC.

+	(ppc64_elf_relocate_section): Modify overflow test for 16-bit

+	fields in instructions to signed/unsigned according to whether

+	the field takes a signed or unsigned value.

+

 2014-03-07  Pedro Alves  <palves@redhat.com>

 	* rs6000-core.c (rs6000coff_core_p): Cast pointers to bfd_vma

--- a/bfd/elf64-ppc.c

+++ b/bfd/elf64-ppc.c

@@ -357,7 +357,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 16,			/* bitsize */

 	 FALSE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_signed, /* complain_on_overflow */

 	 ppc64_elf_branch_reloc, /* special_function */

 	 "R_PPC64_ADDR14",	/* name */

 	 FALSE,			/* partial_inplace */

@@ -374,7 +374,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 16,			/* bitsize */

 	 FALSE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_signed, /* complain_on_overflow */

 	 ppc64_elf_brtaken_reloc, /* special_function */

 	 "R_PPC64_ADDR14_BRTAKEN",/* name */

 	 FALSE,			/* partial_inplace */

@@ -391,7 +391,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 16,			/* bitsize */

 	 FALSE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_signed, /* complain_on_overflow */

 	 ppc64_elf_brtaken_reloc, /* special_function */

 	 "R_PPC64_ADDR14_BRNTAKEN",/* name */

 	 FALSE,			/* partial_inplace */

@@ -632,7 +632,6 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 32,			/* bitsize */

 	 TRUE,			/* pc_relative */

 	 0,			/* bitpos */

-	 /* FIXME: Verify.  Was complain_overflow_bitfield.  */

 	 complain_overflow_signed, /* complain_on_overflow */

 	 bfd_elf_generic_reloc,	/* special_function */

 	 "R_PPC64_REL32",	/* name */

@@ -727,7 +726,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 16,			/* bitsize */

 	 FALSE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_signed, /* complain_on_overflow */

 	 ppc64_elf_sectoff_reloc, /* special_function */

 	 "R_PPC64_SECTOFF",	/* name */

 	 FALSE,			/* partial_inplace */

@@ -1015,7 +1014,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 64,			/* bitsize */

 	 FALSE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_dont, /* complain_on_overflow */

 	 ppc64_elf_toc64_reloc,	/* special_function */

 	 "R_PPC64_TOC",		/* name */

 	 FALSE,			/* partial_inplace */

@@ -1103,7 +1102,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 16,			/* bitsize */

 	 FALSE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_signed, /* complain_on_overflow */

 	 bfd_elf_generic_reloc,	/* special_function */

 	 "R_PPC64_ADDR16_DS",	/* name */

 	 FALSE,			/* partial_inplace */

@@ -1178,7 +1177,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 16,			/* bitsize */

 	 FALSE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_signed, /* complain_on_overflow */

 	 ppc64_elf_sectoff_reloc, /* special_function */

 	 "R_PPC64_SECTOFF_DS",	/* name */

 	 FALSE,			/* partial_inplace */

@@ -1950,7 +1949,7 @@ static reloc_howto_type ppc64_elf_howto_raw[] = {

 	 16,			/* bitsize */

 	 TRUE,			/* pc_relative */

 	 0,			/* bitpos */

-	 complain_overflow_bitfield, /* complain_on_overflow */

+	 complain_overflow_signed, /* complain_on_overflow */

 	 bfd_elf_generic_reloc,	/* special_function */

 	 "R_PPC64_REL16",	/* name */

 	 FALSE,			/* partial_inplace */

@@ -12943,6 +12942,8 @@ ppc64_elf_relocate_section (bfd *output_bfd,

       bfd_vma max_br_offset;

       bfd_vma from;

       const Elf_Internal_Rela orig_rel = *rel;

+      reloc_howto_type *howto;

+      struct reloc_howto_struct alt_howto;

       r_type = ELF64_R_TYPE (rel->r_info);

       r_symndx = ELF64_R_SYM (rel->r_info);

@@ -14507,6 +14508,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,

 	}

       /* Do any further special processing.  */

+      howto = ppc64_elf_howto_table[(int) r_type];

       switch (r_type)

 	{

 	default:

@@ -14581,7 +14583,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,

 	      info->callbacks->einfo

 		(_("%P: %H: error: %s not a multiple of %u\n"),

 		 input_bfd, input_section, rel->r_offset,

-		 ppc64_elf_howto_table[r_type]->name,

+		 howto->name,

 		 mask + 1);

 	      bfd_set_error (bfd_error_bad_value);

 	      ret = FALSE;

@@ -14602,23 +14604,45 @@ ppc64_elf_relocate_section (bfd *output_bfd,

 	  info->callbacks->einfo

 	    (_("%P: %H: unresolvable %s against `%T'\n"),

 	     input_bfd, input_section, rel->r_offset,

-	     ppc64_elf_howto_table[(int) r_type]->name,

+	     howto->name,

 	     h->elf.root.root.string);

 	  ret = FALSE;

 	}

-      r = _bfd_final_link_relocate (ppc64_elf_howto_table[(int) r_type],

-				    input_bfd,

-				    input_section,

-				    contents,

-				    rel->r_offset,

-				    relocation,

-				    addend);

+      /* 16-bit fields in insns mostly have signed values, but a

+	 few insns have 16-bit unsigned values.  Really, we should

+	 have different reloc types.  */

+      if (howto->complain_on_overflow != complain_overflow_dont

+	  && howto->dst_mask == 0xffff

+	  && (input_section->flags & SEC_CODE) != 0)

+	{

+	  enum complain_overflow complain = complain_overflow_signed;

+

+	  insn = bfd_get_32 (input_bfd, contents + (rel->r_offset & ~3));

+	  if (howto->rightshift == 0

+	      ? ((insn & (0x3f << 26)) == 28u << 26 /* andi */

+		 || (insn & (0x3f << 26)) == 24u << 26 /* ori */

+		 || (insn & (0x3f << 26)) == 26u << 26 /* xori */

+		 || (insn & (0x3f << 26)) == 10u << 26 /* cmpli */)

+	      : ((insn & (0x3f << 26)) == 29u << 26 /* andis */

+		 || (insn & (0x3f << 26)) == 25u << 26 /* oris */

+		 || (insn & (0x3f << 26)) == 27u << 26 /* xoris */))

+	    complain = complain_overflow_unsigned;

+	  if (howto->complain_on_overflow != complain)

+	    {

+	      alt_howto = *howto;

+	      alt_howto.complain_on_overflow = complain;

+	      howto = &alt_howto;

+	    }

+	}

+

+      r = _bfd_final_link_relocate (howto, input_bfd, input_section, contents,

+				    rel->r_offset, relocation, addend);

       if (r != bfd_reloc_ok)

 	{

 	  char *more_info = NULL;

-	  const char *reloc_name = ppc64_elf_howto_table[r_type]->name;

+	  const char *reloc_name = howto->name;

 	  if (reloc_dest != DEST_NORMAL)

 	    {

@@ -14638,7 +14662,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,

 		continue;

 	      if (h != NULL

 		  && h->elf.root.type == bfd_link_hash_undefweak

-		  && ppc64_elf_howto_table[r_type]->pc_relative)

+		  && howto->pc_relative)

 		{

 		  /* Assume this is a call protected by other code that

 		     detects the symbol is undefined.  If this is the case,