commit 6911b7dcb8ea17f8b811578dd4ac1ab7bb675e7b
Author: Alan Modra <amodra@gmail.com>
Date: Tue Oct 29 15:37:43 2013 +1030
Add ELFv2 .localentry support.
This defines the ELF symbol st_other field used to encode the number
of instructions between a function "global entry" and its "local entry",
and adds support related to the local entry offset.
include/elf/
* ppc64.h (STO_PPC64_LOCAL_BIT, STO_PPC64_LOCAL_MASK): Define.
(ppc64_decode_local_entry, ppc64_encode_local_entry): New functions.
(PPC64_LOCAL_ENTRY_OFFSET, PPC64_SET_LOCAL_ENTRY_OFFSET): Define.
bfd/
* elf64-ppc.c (struct ppc_stub_hash_entry): Add "other".
(stub_hash_newfunc): Init new ppc_stub_hash_entry field, and one
we forgot, "plt_ent".
(ppc64_elf_add_symbol_hook): Check ELFv1 objects don't have
st_other bits only valid in ELFv2.
(ppc64_elf_merge_symbol_attribute): New function.
(ppc_type_of_stub): Add local_off param to test branch range.
(ppc_build_one_stub): Adjust destinations for ELFv2 locals.
(ppc_size_one_stub, toc_adjusting_stub_needed): Similarly.
(ppc64_elf_size_stubs): Pass local_off to ppc_type_of_stub.
Set "other" field.
(ppc64_elf_relocate_section): Adjust destination for ELFv2 local
calls.
gas/
* config/tc-ppc.c (md_pseudo_table): Add .localentry.
(ppc_elf_localentry): New function.
(ppc_force_relocation): Force relocs on all branches to localenty
symbols.
(ppc_fix_adjustable): Don't reduce such symbols to section+offset.
binutils/
* readelf.c (get_ppc64_symbol_other): New function.
(get_symbol_other): Use it for EM_PPC64.
Index: gdb-7.6.1/bfd/elf64-ppc.c
===================================================================
--- gdb-7.6.1.orig/bfd/elf64-ppc.c
+++ gdb-7.6.1/bfd/elf64-ppc.c
@@ -118,6 +118,7 @@ static bfd_vma opd_entry_value
#define elf_backend_link_output_symbol_hook ppc64_elf_output_symbol_hook
#define elf_backend_special_sections ppc64_elf_special_sections
#define elf_backend_post_process_headers _bfd_elf_set_osabi
+#define elf_backend_merge_symbol_attribute ppc64_elf_merge_symbol_attribute
/* The name of the dynamic interpreter. This is put in the .interp
section. */
@@ -3640,6 +3641,9 @@ struct ppc_stub_hash_entry {
/* Where this stub is being called from, or, in the case of combined
stub sections, the first input section in the group. */
asection *id_sec;
+
+ /* Symbol st_other. */
+ unsigned char other;
};
struct ppc_branch_hash_entry {
@@ -3886,7 +3890,9 @@ stub_hash_newfunc (struct bfd_hash_entry
eh->target_value = 0;
eh->target_section = NULL;
eh->h = NULL;
+ eh->plt_ent = NULL;
eh->id_sec = NULL;
+ eh->other = 0;
}
return entry;
@@ -4629,7 +4635,7 @@ static bfd_boolean
ppc64_elf_add_symbol_hook (bfd *ibfd,
struct bfd_link_info *info,
Elf_Internal_Sym *isym,
- const char **name ATTRIBUTE_UNUSED,
+ const char **name,
flagword *flags ATTRIBUTE_UNUSED,
asection **sec,
bfd_vma *value ATTRIBUTE_UNUSED)
@@ -4649,9 +4655,35 @@ ppc64_elf_add_symbol_hook (bfd *ibfd,
&& strcmp ((*sec)->name, ".opd") == 0)
isym->st_info = ELF_ST_INFO (ELF_ST_BIND (isym->st_info), STT_FUNC);
+ if ((STO_PPC64_LOCAL_MASK & isym->st_other) != 0)
+ {
+ if (abiversion (ibfd) == 0)
+ set_abiversion (ibfd, 2);
+ else if (abiversion (ibfd) == 1)
+ {
+ info->callbacks->einfo (_("%P: symbol '%s' has invalid st_other"
+ " for ABI version 1\n"), name);
+ bfd_set_error (bfd_error_bad_value);
+ return FALSE;
+ }
+ }
+
return TRUE;
}
+/* Merge non-visibility st_other attributes: local entry point. */
+
+static void
+ppc64_elf_merge_symbol_attribute (struct elf_link_hash_entry *h,
+ const Elf_Internal_Sym *isym,
+ bfd_boolean definition,
+ bfd_boolean dynamic)
+{
+ if (definition && !dynamic)
+ h->other = ((isym->st_other & ~ELF_ST_VISIBILITY (-1))
+ | ELF_ST_VISIBILITY (h->other));
+}
+
/* This function makes an old ABI object reference to ".bar" cause the
inclusion of a new ABI object archive that defines "bar".
NAME is a symbol defined in an archive. Return a symbol in the hash
@@ -9586,7 +9618,8 @@ ppc_type_of_stub (asection *input_sec,
const Elf_Internal_Rela *rel,
struct ppc_link_hash_entry **hash,
struct plt_entry **plt_ent,
- bfd_vma destination)
+ bfd_vma destination,
+ unsigned long local_off)
{
struct ppc_link_hash_entry *h = *hash;
bfd_vma location;
@@ -9655,7 +9688,7 @@ ppc_type_of_stub (asection *input_sec,
if (r_type != R_PPC64_REL24)
max_branch_offset = 1 << 15;
- if (branch_offset + max_branch_offset >= 2 * max_branch_offset)
+ if (branch_offset + max_branch_offset >= 2 * max_branch_offset - local_off)
/* We need a stub. Figure out whether a long_branch or plt_branch
is needed later. */
return ppc_stub_long_branch;
@@ -10023,9 +10056,11 @@ ppc_build_one_stub (struct bfd_hash_entr
case ppc_stub_long_branch:
case ppc_stub_long_branch_r2off:
/* Branches are relative. This is where we are going to. */
- off = dest = (stub_entry->target_value
- + stub_entry->target_section->output_offset
- + stub_entry->target_section->output_section->vma);
+ dest = (stub_entry->target_value
+ + stub_entry->target_section->output_offset
+ + stub_entry->target_section->output_section->vma);
+ dest += PPC64_LOCAL_ENTRY_OFFSET (stub_entry->other);
+ off = dest;
/* And this is where we are coming from. */
off -= (stub_entry->stub_offset
@@ -10128,6 +10163,8 @@ ppc_build_one_stub (struct bfd_hash_entr
dest = (stub_entry->target_value
+ stub_entry->target_section->output_offset
+ stub_entry->target_section->output_section->vma);
+ if (stub_entry->stub_type != ppc_stub_plt_branch_r2off)
+ dest += PPC64_LOCAL_ENTRY_OFFSET (stub_entry->other);
bfd_put_64 (htab->brlt->owner, dest,
htab->brlt->contents + br_entry->offset);
@@ -10472,6 +10509,7 @@ ppc_size_one_stub (struct bfd_hash_entry
/* ppc_stub_long_branch or ppc_stub_plt_branch, or their r2off
variants. */
bfd_vma r2off = 0;
+ bfd_vma local_off = 0;
off = (stub_entry->target_value
+ stub_entry->target_section->output_offset
@@ -10500,8 +10538,10 @@ ppc_size_one_stub (struct bfd_hash_entry
off -= size - 4;
}
+ local_off = PPC64_LOCAL_ENTRY_OFFSET (stub_entry->other);
+
/* If the branch offset if too big, use a ppc_stub_plt_branch. */
- if (off + (1 << 25) >= (bfd_vma) (1 << 26))
+ if (off + (1 << 25) >= (bfd_vma) (1 << 26) - local_off)
{
struct ppc_branch_hash_entry *br_entry;
@@ -11097,7 +11137,10 @@ toc_adjusting_stub_needed (struct bfd_li
need a plt_branch stub. A plt_branch stub uses r2. */
else if (dest - (isec->output_offset
+ isec->output_section->vma
- + rel->r_offset) + (1 << 25) >= (2 << 25))
+ + rel->r_offset) + (1 << 25)
+ >= (2u << 25) - PPC64_LOCAL_ENTRY_OFFSET (h
+ ? h->other
+ : sym->st_other))
{
ret = 1;
break;
@@ -11553,6 +11596,7 @@ ppc64_elf_size_stubs (struct bfd_link_in
asection *sym_sec, *code_sec;
bfd_vma sym_value, code_value;
bfd_vma destination;
+ unsigned long local_off;
bfd_boolean ok_dest;
struct ppc_link_hash_entry *hash;
struct ppc_link_hash_entry *fdh;
@@ -11629,12 +11673,16 @@ ppc64_elf_size_stubs (struct bfd_link_in
}
destination = 0;
+ local_off = 0;
if (ok_dest)
{
sym_value += irela->r_addend;
destination = (sym_value
+ sym_sec->output_offset
+ sym_sec->output_section->vma);
+ local_off = PPC64_LOCAL_ENTRY_OFFSET (hash
+ ? hash->elf.other
+ : sym->st_other);
}
code_sec = sym_sec;
@@ -11671,7 +11719,8 @@ ppc64_elf_size_stubs (struct bfd_link_in
/* Determine what (if any) linker stub is needed. */
plt_ent = NULL;
stub_type = ppc_type_of_stub (section, irela, &hash,
- &plt_ent, destination);
+ &plt_ent, destination,
+ local_off);
if (stub_type != ppc_stub_plt_call)
{
@@ -11771,6 +11820,7 @@ ppc64_elf_size_stubs (struct bfd_link_in
}
stub_entry->h = hash;
stub_entry->plt_ent = plt_ent;
+ stub_entry->other = hash ? hash->elf.other : sym->st_other;
stub_entry->addend = irela->r_addend;
if (stub_entry->h != NULL)
@@ -13105,6 +13155,10 @@ ppc64_elf_relocate_section (bfd *output_
+ input_section->output_offset
+ input_section->output_section->vma);
+ relocation += PPC64_LOCAL_ENTRY_OFFSET (fdh
+ ? fdh->elf.other
+ : sym->st_other);
+
if (stub_entry != NULL
&& (stub_entry->stub_type == ppc_stub_long_branch
|| stub_entry->stub_type == ppc_stub_plt_branch)
Index: gdb-7.6.1/include/elf/ppc64.h
===================================================================
--- gdb-7.6.1.orig/include/elf/ppc64.h
+++ gdb-7.6.1/include/elf/ppc64.h
@@ -171,6 +171,53 @@ END_RELOC_NUMBERS (R_PPC64_max)
0 for unspecified or not using any features affected by the differences. */
#define EF_PPC64_ABI 3
+/* The ELFv2 ABI uses three bits in the symbol st_other field of a
+ function definition to specify the number of instructions between a
+ function's global entry point and local entry point.
+ The global entry point is used when it is necessary to set up the
+ toc pointer (r2) for the function. Callers must enter the global
+ entry point with r12 set to the global entry point address. On
+ return from the function, r2 may have a different value to that
+ which it had on entry.
+ The local entry point is used when r2 is known to already be valid
+ for the function. There is no requirement on r12 when using the
+ local entry point, and on return r2 will contain the same value as
+ at entry.
+ A value of zero in these bits means that the function has a single
+ entry point with no requirement on r12 or r2, and that on return r2
+ will contain the same value as at entry.
+ Values of one and seven are reserved. */
+#define STO_PPC64_LOCAL_BIT 5
+#define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT)
+
+// 3 bit other field to bytes.
+static inline unsigned int
+ppc64_decode_local_entry(unsigned int other)
+{
+ return ((1 << other) >> 2) << 2;
+}
+
+// bytes to field value.
+static inline unsigned int
+ppc64_encode_local_entry(unsigned int val)
+{
+ return (val >= 4 * 4
+ ? (val >= 8 * 4
+ ? (val >= 16 * 4 ? 6 : 5)
+ : 4)
+ : (val >= 2 * 4
+ ? 3
+ : (val >= 1 * 4 ? 2 : 0)));
+}
+
+/* st_other to number of bytes. */
+#define PPC64_LOCAL_ENTRY_OFFSET(other) \
+ ppc64_decode_local_entry (((other) & STO_PPC64_LOCAL_MASK) \
+ >> STO_PPC64_LOCAL_BIT)
+/* number of bytes to st_other. */
+#define PPC64_SET_LOCAL_ENTRY_OFFSET(val) \
+ ppc64_encode_local_entry (val) << STO_PPC64_LOCAL_BIT
+
/* Specify the start of the .glink section. */
#define DT_PPC64_GLINK DT_LOPROC