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[RFC PATCH, binutils, ARM 4/9] Use getters/setters to access ARM branch type
- From: "Thomas Preud'homme" <thomas dot preudhomme at foss dot arm dot com>
- To: <binutils at sourceware dot org>
- Date: Wed, 23 Dec 2015 15:57:36 +0800
- Subject: [RFC PATCH, binutils, ARM 4/9] Use getters/setters to access ARM branch type
- Authentication-results: sourceware.org; auth=none
Hi,
[Posting patch series as RFC]
This patch is part of a patch series to add support for ARMv8-M security extension[1] to GNU ld. This specific patch changes all accesses to the branch type stored in the st_target_internal field of a Elf_Internal_Sym structure or in the target_internal field of a elf_link_hash_entry structure by getter and setters. This is required by subsequent patches to also store in these fields whether a symbol is a special symbol indicating a secure entry function.
[1] Software requirements for ARMv8-M security extension are described in document ARM-ECM-0359818 [2]
[2] Available on http://infocenter.arm.com in Developer guides and articles > Software development > ARMÂv8-M Security Extensions: Requirements on Development Tools
ChangeLog entries are as follow:
*** bfd/ChangeLog ***
2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
* elf32-arm.c (elf32_arm_size_stubs): Use new macros
ARM_GET_SYM_BRANCH_TYPE and ARM_SET_SYM_BRANCH_TYPE to respectively get
and set branch type of a symbol.
(bfd_elf32_arm_process_before_allocation): Likewise.
(elf32_arm_relocate_section): Likewise and fix identation along the
way.
(allocate_dynrelocs_for_symbol): Likewise.
(elf32_arm_finish_dynamic_symbol): Likewise.
(elf32_arm_swap_symbol_in): Likewise.
(elf32_arm_swap_symbol_out): Likewise.
*** gas/ChangeLog ***
2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
* config/tc-arm.c (arm_adjust_symtab): Use ARM_SET_SYM_BRANCH_TYPE to
set branch type of a symbol.
*** gdb/ChangeLog ***
2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
* arm-tdep.c (arm_elf_make_msymbol_special): Use
ARM_GET_SYM_BRANCH_TYPE to get branch type of a symbol.
*** include/elf/ChangeLog ***
2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
* arm.h (ARM_SYM_BRANCH_TYPE): Replace by ...
(ARM_GET_SYM_BRANCH_TYPE): ... this ...
(ARM_SET_SYM_BRANCH_TYPE): ... and this.
*** ld/ChangeLog ***
2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
(gld${EMULATION_NAME}_finish): Use ARM_GET_SYM_BRANCH_TYPE to get
branch type of a symbol.
*** opcodes/ChangeLog ***
2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
* arm-dis.c (get_sym_code_type): Use ARM_GET_SYM_BRANCH_TYPE to get
branch type of a symbol.
(print_insn): Likewise.
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 8450733016a496ec34533e8aad4900be16dc5849..6c8060a2c559ff5bd8a8e7f414f0a471dfa32cc8 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -5383,7 +5383,8 @@ elf32_arm_size_stubs (bfd *output_bfd,
+ sym_sec->output_offset
+ sym_sec->output_section->vma);
st_type = ELF_ST_TYPE (sym->st_info);
- branch_type = ARM_SYM_BRANCH_TYPE (sym);
+ branch_type =
+ ARM_GET_SYM_BRANCH_TYPE (sym->st_target_internal);
sym_name
= bfd_elf_string_from_elf_section (input_bfd,
symtab_hdr->sh_link,
@@ -5458,7 +5459,8 @@ elf32_arm_size_stubs (bfd *output_bfd,
goto error_ret_free_internal;
}
st_type = hash->root.type;
- branch_type = hash->root.target_internal;
+ branch_type =
+ ARM_GET_SYM_BRANCH_TYPE (hash->root.target_internal);
sym_name = hash->root.root.root.string;
}
@@ -6551,7 +6553,8 @@ bfd_elf32_arm_process_before_allocation (bfd *abfd,
/* This one is a call from arm code. We need to look up
the target of the call. If it is a thumb target, we
insert glue. */
- if (h->target_internal == ST_BRANCH_TO_THUMB)
+ if (ARM_GET_SYM_BRANCH_TYPE (h->target_internal)
+ == ST_BRANCH_TO_THUMB)
record_arm_to_thumb_glue (link_info, h);
break;
@@ -11382,28 +11385,34 @@ elf32_arm_relocate_section (bfd * output_bfd,
and we won't let anybody mess with it. Also, we have to do
addend adjustments in case of a R_ARM_TLS_GOTDESC relocation
both in relaxed and non-relaxed cases. */
- if ((elf32_arm_tls_transition (info, r_type, h) != (unsigned)r_type)
- || (IS_ARM_TLS_GNU_RELOC (r_type)
- && !((h ? elf32_arm_hash_entry (h)->tls_type :
- elf32_arm_local_got_tls_type (input_bfd)[r_symndx])
- & GOT_TLS_GDESC)))
- {
- r = elf32_arm_tls_relax (globals, input_bfd, input_section,
- contents, rel, h == NULL);
- /* This may have been marked unresolved because it came from
- a shared library. But we've just dealt with that. */
- unresolved_reloc = 0;
- }
- else
- r = bfd_reloc_continue;
+ if ((elf32_arm_tls_transition (info, r_type, h) != (unsigned)r_type)
+ || (IS_ARM_TLS_GNU_RELOC (r_type)
+ && !((h ? elf32_arm_hash_entry (h)->tls_type :
+ elf32_arm_local_got_tls_type (input_bfd)[r_symndx])
+ & GOT_TLS_GDESC)))
+ {
+ r = elf32_arm_tls_relax (globals, input_bfd, input_section,
+ contents, rel, h == NULL);
+ /* This may have been marked unresolved because it came from
+ a shared library. But we've just dealt with that. */
+ unresolved_reloc = 0;
+ }
+ else
+ r = bfd_reloc_continue;
- if (r == bfd_reloc_continue)
- r = elf32_arm_final_link_relocate (howto, input_bfd, output_bfd,
- input_section, contents, rel,
- relocation, info, sec, name, sym_type,
- (h ? h->target_internal
- : ARM_SYM_BRANCH_TYPE (sym)), h,
- &unresolved_reloc, &error_message);
+ if (r == bfd_reloc_continue)
+ {
+ unsigned char branch_type =
+ h ? ARM_GET_SYM_BRANCH_TYPE (h->target_internal)
+ : ARM_GET_SYM_BRANCH_TYPE (sym->st_target_internal);
+
+ r = elf32_arm_final_link_relocate (howto, input_bfd, output_bfd,
+ input_section, contents, rel,
+ relocation, info, sec, name,
+ sym_type, branch_type, h,
+ &unresolved_reloc,
+ &error_message);
+ }
/* Dynamic relocs are not propagated for SEC_DEBUGGING sections
because such sections are not SEC_ALLOC and thus ld.so will
@@ -14125,7 +14134,7 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
/* Make sure the function is not marked as Thumb, in case
it is the target of an ABS32 relocation, which will
point to the PLT entry. */
- h->target_internal = ST_BRANCH_TO_ARM;
+ ARM_SET_SYM_BRANCH_TYPE (h->target_internal, ST_BRANCH_TO_ARM);
}
/* VxWorks executables have a second set of relocations for
@@ -14273,7 +14282,7 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
/* Allocate stubs for exported Thumb functions on v4t. */
if (!htab->use_blx && h->dynindx != -1
&& h->def_regular
- && h->target_internal == ST_BRANCH_TO_THUMB
+ && ARM_GET_SYM_BRANCH_TYPE (h->target_internal) == ST_BRANCH_TO_THUMB
&& ELF_ST_VISIBILITY (h->other) == STV_DEFAULT)
{
struct elf_link_hash_entry * th;
@@ -14293,12 +14302,12 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
myh = (struct elf_link_hash_entry *) bh;
myh->type = ELF_ST_INFO (STB_LOCAL, STT_FUNC);
myh->forced_local = 1;
- myh->target_internal = ST_BRANCH_TO_THUMB;
+ ARM_SET_SYM_BRANCH_TYPE (myh->target_internal, ST_BRANCH_TO_THUMB);
eh->export_glue = myh;
th = record_arm_to_thumb_glue (info, h);
/* Point the symbol at the stub. */
h->type = ELF_ST_INFO (ELF_ST_BIND (h->type), STT_FUNC);
- h->target_internal = ST_BRANCH_TO_ARM;
+ ARM_SET_SYM_BRANCH_TYPE (h->target_internal, ST_BRANCH_TO_ARM);
h->root.u.def.section = th->root.u.def.section;
h->root.u.def.value = th->root.u.def.value & ~1;
}
@@ -14953,7 +14962,7 @@ elf32_arm_finish_dynamic_symbol (bfd * output_bfd,
/* At least one non-call relocation references this .iplt entry,
so the .iplt entry is the function's canonical address. */
sym->st_info = ELF_ST_INFO (ELF_ST_BIND (sym->st_info), STT_FUNC);
- sym->st_target_internal = ST_BRANCH_TO_ARM;
+ ARM_SET_SYM_BRANCH_TYPE (sym->st_target_internal, ST_BRANCH_TO_ARM);
sym->st_shndx = (_bfd_elf_section_from_bfd_section
(output_bfd, htab->root.iplt->output_section));
sym->st_value = (h->plt.offset
@@ -15237,7 +15246,9 @@ elf32_arm_finish_dynamic_sections (bfd * output_bfd, struct bfd_link_info * info
eh = elf_link_hash_lookup (elf_hash_table (info), name,
FALSE, FALSE, TRUE);
- if (eh != NULL && eh->target_internal == ST_BRANCH_TO_THUMB)
+ if (eh != NULL
+ && ARM_GET_SYM_BRANCH_TYPE (eh->target_internal)
+ == ST_BRANCH_TO_THUMB)
{
dyn.d_un.d_val |= 1;
bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
@@ -17325,6 +17336,7 @@ elf32_arm_swap_symbol_in (bfd * abfd,
{
if (!bfd_elf32_swap_symbol_in (abfd, psrc, pshn, dst))
return FALSE;
+ dst->st_target_internal = 0;
/* New EABI objects mark thumb function symbols by setting the low bit of
the address. */
@@ -17334,20 +17346,21 @@ elf32_arm_swap_symbol_in (bfd * abfd,
if (dst->st_value & 1)
{
dst->st_value &= ~(bfd_vma) 1;
- dst->st_target_internal = ST_BRANCH_TO_THUMB;
+ ARM_SET_SYM_BRANCH_TYPE (dst->st_target_internal,
+ ST_BRANCH_TO_THUMB);
}
else
- dst->st_target_internal = ST_BRANCH_TO_ARM;
+ ARM_SET_SYM_BRANCH_TYPE (dst->st_target_internal, ST_BRANCH_TO_ARM);
}
else if (ELF_ST_TYPE (dst->st_info) == STT_ARM_TFUNC)
{
dst->st_info = ELF_ST_INFO (ELF_ST_BIND (dst->st_info), STT_FUNC);
- dst->st_target_internal = ST_BRANCH_TO_THUMB;
+ ARM_SET_SYM_BRANCH_TYPE (dst->st_target_internal, ST_BRANCH_TO_THUMB);
}
else if (ELF_ST_TYPE (dst->st_info) == STT_SECTION)
- dst->st_target_internal = ST_BRANCH_LONG;
+ ARM_SET_SYM_BRANCH_TYPE (dst->st_target_internal, ST_BRANCH_LONG);
else
- dst->st_target_internal = ST_BRANCH_UNKNOWN;
+ ARM_SET_SYM_BRANCH_TYPE (dst->st_target_internal, ST_BRANCH_UNKNOWN);
return TRUE;
}
@@ -17367,7 +17380,7 @@ elf32_arm_swap_symbol_out (bfd *abfd,
of the address set, as per the new EABI. We do this unconditionally
because objcopy does not set the elf header flags until after
it writes out the symbol table. */
- if (src->st_target_internal == ST_BRANCH_TO_THUMB)
+ if (ARM_GET_SYM_BRANCH_TYPE (src->st_target_internal) == ST_BRANCH_TO_THUMB)
{
newsym = *src;
if (ELF_ST_TYPE (src->st_info) != STT_GNU_IFUNC)
diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c
index 70ce3020a09e329c87b636a85d82f8be17e35094..3721be4a1dc8d85e4d0e5c28c0b2972c75ca6cc2 100644
--- a/gas/config/tc-arm.c
+++ b/gas/config/tc-arm.c
@@ -24176,8 +24176,8 @@ arm_adjust_symtab (void)
/* If it's a .thumb_func, declare it as so,
otherwise tag label as .code 16. */
if (THUMB_IS_FUNC (sym))
- elf_sym->internal_elf_sym.st_target_internal
- = ST_BRANCH_TO_THUMB;
+ ARM_SET_SYM_BRANCH_TYPE (elf_sym->internal_elf_sym.st_target_internal,
+ ST_BRANCH_TO_THUMB);
else if (EF_ARM_EABI_VERSION (meabi_flags) < EF_ARM_EABI_VER4)
elf_sym->internal_elf_sym.st_info =
ELF_ST_INFO (bind, STT_ARM_16BIT);
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 6ce6f09c37ff164d327281df1cdbe5a3d4f4136f..3e8c4b599a2cc1b3762e21c40c88cdf49f4e2101 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -9628,7 +9628,8 @@ coff_sym_is_thumb (int val)
static void
arm_elf_make_msymbol_special(asymbol *sym, struct minimal_symbol *msym)
{
- if (ARM_SYM_BRANCH_TYPE (&((elf_symbol_type *)sym)->internal_elf_sym)
+ elf_symbol_type *elfsym = (elf_symbol_type *) sym;
+ if (ARM_GET_SYM_BRANCH_TYPE (elfsym->internal_elf_sym.st_target_internal)
== ST_BRANCH_TO_THUMB)
MSYMBOL_SET_SPECIAL (msym);
}
diff --git a/include/elf/arm.h b/include/elf/arm.h
index a477f17dd8c6f05e736e46bc6402778f0ad7f19b..1a7fe1cf947bfb890884f77b3b30c035046b3fd5 100644
--- a/include/elf/arm.h
+++ b/include/elf/arm.h
@@ -356,7 +356,9 @@ enum arm_st_branch_type {
ST_BRANCH_UNKNOWN
};
-#define ARM_SYM_BRANCH_TYPE(SYM) \
- ((enum arm_st_branch_type) (SYM)->st_target_internal)
+#define ARM_GET_SYM_BRANCH_TYPE(SYM_TARGET_INTERNAL) \
+ ((enum arm_st_branch_type) ((SYM_TARGET_INTERNAL) & 3))
+#define ARM_SET_SYM_BRANCH_TYPE(SYM_TARGET_INTERNAL,TYPE) \
+ ((SYM_TARGET_INTERNAL) = ((SYM_TARGET_INTERNAL) & ~3) | ((TYPE) & 3))
#endif /* _ELF_ARM_H */
diff --git a/ld/emultempl/armelf.em b/ld/emultempl/armelf.em
index a3b52e685fcd2d415737f3ee9ed461978a2419f6..f20820733e37b78e45eb6c5f466f6ad2ccea9a14 100644
--- a/ld/emultempl/armelf.em
+++ b/ld/emultempl/armelf.em
@@ -450,7 +450,8 @@ gld${EMULATION_NAME}_finish (void)
h = bfd_link_hash_lookup (link_info.hash, entry_symbol.name,
FALSE, FALSE, TRUE);
eh = (struct elf_link_hash_entry *)h;
- if (!h || eh->target_internal != ST_BRANCH_TO_THUMB)
+ if (!h || ARM_GET_SYM_BRANCH_TYPE (eh->target_internal)
+ != ST_BRANCH_TO_THUMB)
return;
}
diff --git a/opcodes/arm-dis.c b/opcodes/arm-dis.c
index 50b8649a9477d641e7ee88a130f35404dd68436b..ee8476b61982b7d0da03b1b7458b4f3c0acf8c55 100644
--- a/opcodes/arm-dis.c
+++ b/opcodes/arm-dis.c
@@ -6086,7 +6086,8 @@ get_sym_code_type (struct disassemble_info *info,
/* If the symbol has function type then use that. */
if (type == STT_FUNC || type == STT_GNU_IFUNC)
{
- if (ARM_SYM_BRANCH_TYPE (&es->internal_elf_sym) == ST_BRANCH_TO_THUMB)
+ if (ARM_GET_SYM_BRANCH_TYPE (es->internal_elf_sym.st_target_internal)
+ == ST_BRANCH_TO_THUMB)
*map_type = MAP_THUMB;
else
*map_type = MAP_ARM;
@@ -6388,9 +6389,9 @@ print_insn (bfd_vma pc, struct disassemble_info *info, bfd_boolean little)
es = *(elf_symbol_type **)(info->symbols);
type = ELF_ST_TYPE (es->internal_elf_sym.st_info);
- is_thumb = ((ARM_SYM_BRANCH_TYPE (&es->internal_elf_sym)
- == ST_BRANCH_TO_THUMB)
- || type == STT_ARM_16BIT);
+ is_thumb =
+ ((ARM_GET_SYM_BRANCH_TYPE (es->internal_elf_sym.st_target_internal)
+ == ST_BRANCH_TO_THUMB) || type == STT_ARM_16BIT);
}
else if (bfd_asymbol_flavour (*info->symbols)
== bfd_target_mach_o_flavour)
The patch doesn't show any regression when running the binutils-gdb testsuite for the arm-none-eabi target.
Any comments?
Best regards,
Thomas