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kvx bfd signed calculations and _bfd_kvx_elf_resolve_relocation

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It is generally a good idea to avoid signed arithmetic on values
extracted from object files, to avoid ubsan warnings on overflow.
This patch replaces some uses of bfd_signed_vma in the kvx backend
with bfd_vma, and removes _bfd_kvx_elf_resolve_relocation, a
do-nothing function.  In the process of making this patch I noticed
some dead code in the GOT entry handling, setting value to
got_entry_addr but using "off" in the _bfd_final_link_relocate call.
Since kvx_calculate_got_entry_vma also returns the GOT offset, I
presume the code is correct, but I've left the dead code and comment
there.

	* elfxx-kvx.h (_bfd_kvx_elf_resolve_relocation): Delete.
	* elfxx-kvx.c (kvx_signed_overflow): Rewrite using unsigned
	arithmetic.
	(_bfd_kvx_elf_resolve_relocation): Delete.
	* elfnn-kvx.c (kvx_relocate): Update for
	_bfd_kvx_elf_resolve_relocation removal.
	(elfNN_kvx_final_link_relocate): Likewise.  Don't use a signed
	addend.
This commit is contained in:
Alan Modra
2023-08-22 16:06:32 +09:30
parent d530ba0af9
commit c5ed8c6376
3 changed files with 20 additions and 46 deletions
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46
bfd/elfnn-kvx.c
View File

@@ -670,14 +670,9 @@ kvx_relocate (unsigned int r_type, bfd *input_bfd, asection *input_section,
bfd_vma offset, bfd_vma value)
{
reloc_howto_type *howto;
bfd_vma place;
howto = elfNN_kvx_howto_from_type (input_bfd, r_type);
place = (input_section->output_section->vma + input_section->output_offset
+ offset);
r_type = elfNN_kvx_bfd_reloc_from_type (input_bfd, r_type);
value = _bfd_kvx_elf_resolve_relocation (r_type, place, value, 0, false);
return _bfd_kvx_elf_put_addend (input_bfd,
input_section->contents + offset, r_type,
howto, value);
@@ -2000,7 +1995,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
unsigned long r_symndx;
bfd_byte *hit_data = contents + rel->r_offset;
bfd_vma place, off;
bfd_signed_vma signed_addend;
bfd_vma addend;
struct elf_kvx_link_hash_table *globals;
bool weak_undef_p;
asection *base_got;
@@ -2030,8 +2025,8 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
/* Get addend, accumulating the addend for consecutive relocs
which refer to the same offset. */
signed_addend = saved_addend ? *saved_addend : 0;
signed_addend += rel->r_addend;
addend = saved_addend ? *saved_addend : 0;
addend += rel->r_addend;
weak_undef_p = (h ? h->root.type == bfd_link_hash_undefweak
: bfd_is_und_section (sym_sec));
@@ -2078,7 +2073,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
skip = false;
relocate = false;
outrel.r_addend = signed_addend;
outrel.r_addend = addend;
outrel.r_offset =
_bfd_elf_section_offset (output_bfd, info, input_section,
rel->r_offset);
@@ -2160,24 +2155,24 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
return bfd_reloc_ok;
rret = check_signed_overflow (complain_overflow_signed, bfd_r_type,
input_bfd, value + signed_addend);
input_bfd, value + addend);
if (rret != bfd_reloc_ok)
return rret;
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, value,
signed_addend);
addend);
}
skip_because_pic:
rret = check_signed_overflow (complain_overflow_signed, bfd_r_type,
input_bfd, value + signed_addend);
input_bfd, value + addend);
if (rret != bfd_reloc_ok)
return rret;
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, value,
signed_addend);
addend);
break;
case BFD_RELOC_KVX_PCREL17:
@@ -2231,7 +2226,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
+ stub_entry->stub_sec->output_section->vma);
/* We have redirected the destination to stub entry address,
so ignore any addend record in the original rela entry. */
signed_addend = 0;
addend = 0;
}
}
*unresolved_reloc_p = false;
@@ -2250,7 +2245,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
case BFD_RELOC_KVX_S43_PCREL_EX6:
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, value,
signed_addend);
addend);
break;
case BFD_RELOC_KVX_S37_TLS_LE_LO10:
@@ -2261,8 +2256,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
case BFD_RELOC_KVX_S43_TLS_LE_EX6:
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset,
value - tpoff_base (info),
signed_addend);
value - tpoff_base (info), addend);
break;
case BFD_RELOC_KVX_S37_TLS_DTPOFF_LO10:
@@ -2273,8 +2267,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
case BFD_RELOC_KVX_S43_TLS_DTPOFF_EX6:
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset,
value - dtpoff_base (info),
signed_addend);
value - dtpoff_base (info), addend);
case BFD_RELOC_KVX_S37_TLS_GD_UP27:
case BFD_RELOC_KVX_S37_TLS_GD_LO10:
@@ -2302,8 +2295,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
value = symbol_got_offset (input_bfd, h, r_symndx);
_bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, value,
signed_addend);
contents, rel->r_offset, value, addend);
*unresolved_reloc_p = false;
break;
@@ -2326,7 +2318,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, value,
signed_addend);
addend);
}
break;
@@ -2347,7 +2339,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
value -= basegot->output_section->vma + basegot->output_offset;
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, value,
signed_addend);
addend);
}
break;
@@ -2373,18 +2365,15 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
printf("GOT_LO/HI for %s, value %x\n", h->root.root.string, value);
#endif
/* value = _bfd_kvx_elf_resolve_relocation (bfd_r_type, place, value, */
/* 0, weak_undef_p); */
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, value,
signed_addend);
addend);
}
else
{
#ifdef UGLY_DEBUG
printf("GOT_LO/HI with h NULL, initial value %x\n", value);
#endif
bfd_vma addend = 0;
struct elf_kvx_local_symbol *locals = elf_kvx_locals (input_bfd);
if (locals == NULL)
@@ -2433,8 +2422,7 @@ elfNN_kvx_final_link_relocate (reloc_howto_type *howto,
value = got_entry_addr;
return _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset, off,
addend);
contents, rel->r_offset, off, 0);
}
break;

15
bfd/elfxx-kvx.c
View File

@@ -46,13 +46,12 @@ kvx_unsigned_overflow (bfd_vma value, unsigned int bits)
static bfd_reloc_status_type
kvx_signed_overflow (bfd_vma value, unsigned int bits)
{
bfd_signed_vma svalue = (bfd_signed_vma) value;
bfd_signed_vma lim;
bfd_vma lim;
if (bits >= sizeof (bfd_vma) * 8)
return bfd_reloc_ok;
lim = (bfd_signed_vma) 1 << (bits - 1);
if (svalue < -lim || svalue >= lim)
lim = (bfd_vma) 1 << (bits - 1);
if (value + lim >= lim * 2)
return bfd_reloc_overflow;
return bfd_reloc_ok;
}
@@ -150,14 +149,6 @@ _bfd_kvx_elf_put_addend (bfd *abfd,
return status;
}
bfd_vma
_bfd_kvx_elf_resolve_relocation (bfd_reloc_code_real_type r_type ATTRIBUTE_UNUSED,
bfd_vma place ATTRIBUTE_UNUSED, bfd_vma value,
bfd_vma addend ATTRIBUTE_UNUSED, bool weak_undef_p ATTRIBUTE_UNUSED)
{
return value;
}
bool
_bfd_kvx_elf_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
{

5
bfd/elfxx-kvx.h
View File

@@ -51,11 +51,6 @@ extern bfd_reloc_status_type
_bfd_kvx_elf_put_addend (bfd *, bfd_byte *, bfd_reloc_code_real_type,
reloc_howto_type *, bfd_signed_vma);
bfd_vma
_bfd_kvx_elf_resolve_relocation (bfd_reloc_code_real_type r_type,
bfd_vma place, bfd_vma value,
bfd_vma addend, bool weak_undef_p);
bool
kvx_elf32_init_stub_bfd (struct bfd_link_info *info,
bfd *stub_bfd);