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[RFC] Add IFUNC support for MIPS (v3)
- From: Faraz Shahbazker <faraz dot shahbazker at imgtec dot com>
- To: "binutils at sourceware dot org" <binutils at sourceware dot org>
- Cc: <rdsandiford at googlemail dot com>
- Date: Mon, 21 Sep 2015 11:50:36 -0700
- Subject: [RFC] Add IFUNC support for MIPS (v3)
- Authentication-results: sourceware.org; auth=none
- References: <5583540C dot 7070800 at imgtec dot com> <87381jtr31 dot fsf at googlemail dot com> <55899D52 dot 1050000 at imgtec dot com> <87vbeegucz dot fsf at googlemail dot com> <5589AFCD dot 10905 at imgtec dot com> <DCB1C42372B1674B8F912A294CCB775A71680718 at BADAG02 dot ba dot imgtec dot org> <87615awnv8 dot fsf at googlemail dot com>
Hi,
glibc patch review is close to completion. Requesting fresh comments on the binutils patch.
Regards,
Faraz Shahbazker
bfd/ChangeLog:
* bfd-in2.h (BFD_RELOC_MIPS_IRELATIVE): New relocation.
* elf32-mips.c
(elf_mips_eh_howto table): Howto for BFD_RELOC_MIPS_IRELATIVE.
(bfd_elf32_bfd_reloc_type_lookup): Case for R_MIPS_IRELATIVE.
(bfd_elf32_bfd_reloc_name_lookup): Case for R_MIPS_IRELATIVE.
(mips_elf32_rtype_to_howto): Case for R_MIPS_IRELATIVE
* elfxx-mips.c
(struct mips_got_info): New fields general_gotno and
assigned_general_gotno.
(struct mips_elf_link_hash_entry): New fields for offset in to
IPLT/IGOT and flags to indicate symbol needs IPLT or IRELOC.
(mips_elf_link_hash_table): New fields for size of IPLT stubs
and hash-table for local IFUNC symbols.
(MIPS16_P): New macro to check ASE flag.
(mips16_exec_iplt_entry): Template for mips16 IPLT stub.
(mips32_exec_iplt_entry): Template for mips32 IPLT stub.
(mips32r6_exec_iplt_entry): Template for mips32 R6 IPLT stub.
(micromips32_exec_iplt_entry): Template for micromips32 stub.
(mips64_exec_iplt_entry): Template for mips64 IPLT stub.
(mips64_48b_exec_iplt_entry): Template for mips64 IPLT stub.
(mips_elf_link_hash_newfunc): Initialization of new
mips_elf_link_hash_entry elements.
(mips_elf_create_stub_symbol): Set ISA bit in address and ST_MIPS16
type for mips16 IPLT stubs.
(mips_elf_rel_dyn_section): Moved up to avoid forward declaration.
(mips_get_irel_section): New function.
(mips_elf_allocate_ireloc): Likewise.
(mips_elf_allocate_iplt): Likewise.
(mips_elf_check_local_symbols): Likewise.
(mips_elf_check_symbols): Allocate an IPLT entry and/or dynamic
relocation for defined IFUNC symbols and set has_gnu_symbols.
(mips_elf_count_got_entry): Skip counting of IFUNC entries.
(mips_elf_got16_entry): Add argument h and pass it to
mips_elf_create_local_got_entry instead of NULL.
(mips_elf_create_local_got_entry): Add check for sufficient general
GOT entries. Assign local IFUNCs from general GOT entries pool.
(mips_elf_record_global_got_symbol): Keep global IFUNC symbols
in the general GOT region instead of moving them to global GOT.
(mips_use_local_got_p): Return TRUE for all IFUNC symbol definitions.
(mips_elf_count_got_symbols): Count global IFUNCs under general
GOT entries instead of global.
(mips_elf_count_general_got_symbols): New function.
(mips_elf_create_ifunc_sections): New function.
(get_local_sym_hash): Likewise.
(mips_elf_calculate_relocation): Create hash-table for local IFUNC
symbols and condition them to be accessed through GOT.
Point IFUNC symbol value to IPLT stub for symbols that need IPLT.
Force global IFUNC to be allocated from local GOT region.
(mips_elf_create_dynamic_relocation): Emit IRELATIVE relocation
instead of REL32 for local IFUNC reference. Relax assertion for
IFUNC symbols in explicit GOT region to have dynamic relocations.
(_bfd_mips_elf_section_processing): Size .igot section.
(_bfd_mips_elf_check_relocs): Check need to create IFUNC sections.
If symbol is an IFUNC, don't convert it to an STT_FUNC. Relax error
checking to allow local IFUNCs to be accessed via call16 reloc.
(_bfd_mips_elf_adjust_dynamic_symbol): Add STT_GNU_IFUNC to sanity
check.
(_bfd_mips_elf_always_size_sections): Allocate relocs for local IFUNCs.
(mips_elf_lay_out_got): Count general GOT entries. Offset local entries
to follow general entries.
(_bfd_mips_elf_size_dynamic_sections): Exclude IPLT and IGOT.
Create dynamic tag for DT_MIPS_GENERAL_GOTNO if needed.
(_bfd_mips_elf_relocate_section): Relax error checking to allow
local IFUNCs to be accessed via standalone got16 reloc.
(mips_elf_create_iplt): New function.
(misp_elf_check_local_got_index): Likewise.
(mips_elf_create_ireloc): Likewise.
(_bfd_mips_elf_finish_dynamic_symbol): Create IPLT stub/IREL
relocation for IFUNC symbols as necessary. Set IFUNC symbol value
to the IPLT entry address for executable objects.
(_bfd_mips_elf_finish_local_dynamic_symbol): New function.
(_bfd_mips_elf_finish_dynamic_sections): Call
_bfd_mips_elf_finish_local_dynamic_symbol for all local IFUNCs.
Set values of dynamic tag - DT_MIPS_GENERAL_GOTNO.
(local_htab_hash): New function, hash table for local IFUNCs.
(loc_htab_eq): New comparison function for local IFUNC hash table.
(_bfd_mips_elf_link_hash_table_free): New function.
(_bfd_mips_elf_link_hash_table_create): Allocate a hash table for
local IFUNCs.
(_bfd_mips_elf_get_target_dtag): Add cases for dynamic tag -
DT_MIPS_GENERAL_GOTNO.
(_bfd_mips_post_process_headers): If ELF uses GNU IFUNCs, set
ABIVERSION to 4.
* libbfd.h
(bfd_reloc_code_real_names): Entry for BFD_RELOC_MIPS_IRELATIVE.
* reloc.c
(ENUMDOC): BFD_RELOC_MIPS_IRELATIVE entry.
binutils/ChangeLog:
* readelf.c:
(get_mips_dynamic_type): Add case for DT_MIPS_GENERAL_GOTNO.
(dynamic_section_mips_val): Add case for DT_MIPS_GENERAL_GOTNO.
elfcpp/ChangeLog:
* elfcpp.h
(enum DT): Add cases for dynamic tag DT_MIPS_GENERAL_GOTNO.
include/elf/ChangeLog:
* mips.h
(START_RELOC_NUMBERS): Entry for R_MIPS_IRELATIVE.
(DT_MIPS_GENERAL_GOTNO): New dynamic tag.
---
bfd/bfd-in2.h | 3 +
bfd/elf32-mips.c | 22 ++
bfd/elfxx-mips.c | 1016 ++++++++++++++++++++++++++++++++++++++++++++++++----
bfd/libbfd.h | 1 +
bfd/reloc.c | 5 +
binutils/readelf.c | 3 +
elfcpp/elfcpp.h | 2 +
include/elf/mips.h | 7 +
8 files changed, 986 insertions(+), 73 deletions(-)
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 51fa54f..99e0061 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -3040,6 +3040,9 @@ to compensate for the borrow when the low bits are added. */
BFD_RELOC_MIPS_JUMP_SLOT,
+/* MIPS support for STT_GNU_IFUNC. */
+ BFD_RELOC_MIPS_IRELATIVE,
+
/* Moxie ELF relocations. */
BFD_RELOC_MOXIE_10_PCREL,
diff --git a/bfd/elf32-mips.c b/bfd/elf32-mips.c
index fff08e5..429febc 100644
--- a/bfd/elf32-mips.c
+++ b/bfd/elf32-mips.c
@@ -1646,6 +1646,22 @@ static reloc_howto_type elf_mips_eh_howto =
0xffffffff, /* dst_mask */
FALSE); /* pcrel_offset */
+/* STT_GNU_IFUNC support. */
+static reloc_howto_type elf_mips_irelative_howto =
+ HOWTO (R_MIPS_IRELATIVE, /* type */
+ 0, /* rightshift */
+ 2, /* size (0 = byte, 1 = short, 2 = long) */
+ 32, /* bitsize */
+ FALSE, /* pc_relative */
+ 0, /* bitpos */
+ complain_overflow_bitfield,/* complain_on_overflow */
+ bfd_elf_generic_reloc, /* special_function */
+ "R_MIPS_IRELATIVE", /* name */
+ TRUE, /* partial_inplace */
+ 0xffffffff, /* src_mask */
+ 0xffffffff, /* dst_mask */
+ FALSE); /* pcrel_offset */
+
/* Set the GP value for OUTPUT_BFD. Returns FALSE if this is a
dangerous relocation. */
@@ -2126,6 +2142,8 @@ bfd_elf32_bfd_reloc_type_lookup (bfd *abfd, bfd_reloc_code_real_type code)
return &elf_mips_jump_slot_howto;
case BFD_RELOC_MIPS_EH:
return &elf_mips_eh_howto;
+ case BFD_RELOC_MIPS_IRELATIVE:
+ return &elf_mips_irelative_howto;
}
}
@@ -2173,6 +2191,8 @@ bfd_elf32_bfd_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
return &elf_mips_jump_slot_howto;
if (strcasecmp (elf_mips_eh_howto.name, r_name) == 0)
return &elf_mips_eh_howto;
+ if (strcasecmp (elf_mips_irelative_howto.name, r_name) == 0)
+ return &elf_mips_irelative_howto;
return NULL;
}
@@ -2199,6 +2219,8 @@ mips_elf32_rtype_to_howto (unsigned int r_type,
return &elf_mips_jump_slot_howto;
case R_MIPS_EH:
return &elf_mips_eh_howto;
+ case R_MIPS_IRELATIVE:
+ return &elf_mips_irelative_howto;
default:
if (r_type >= R_MICROMIPS_min && r_type < R_MICROMIPS_max)
return &elf_micromips_howto_table_rel[r_type - R_MICROMIPS_min];
diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index 5ece52d..0dd1331 100644
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -45,6 +45,7 @@
#include "coff/mips.h"
#include "hashtab.h"
+#include "objalloc.h"
/* Types of TLS GOT entry. */
enum mips_got_tls_type {
@@ -165,10 +166,14 @@ struct mips_got_info
unsigned int tls_assigned_gotno;
/* The number of local .got entries, eventually including page entries. */
unsigned int local_gotno;
+ /* The number of explicitly relocated .got entries. */
+ unsigned int general_gotno;
/* The maximum number of page entries needed. */
unsigned int page_gotno;
/* The number of relocations needed for the GOT entries. */
unsigned int relocs;
+ /* The first unused general .got entry. */
+ unsigned int assigned_general_gotno;
/* The first unused local .got entry. */
unsigned int assigned_low_gotno;
/* The last unused local .got entry. */
@@ -375,6 +380,12 @@ struct mips_elf_link_hash_entry
being called returns a floating point value. */
asection *call_fp_stub;
+ /* Offset into the IPLT table. */
+ bfd_vma iplt_offset;
+
+ /* Offset into the IGOT table. */
+ bfd_vma igot_offset;
+
/* The highest GGA_* value that satisfies all references to this symbol. */
unsigned int global_got_area : 2;
@@ -413,6 +424,12 @@ struct mips_elf_link_hash_entry
/* Does this symbol resolve to a PLT entry? */
unsigned int use_plt_entry : 1;
+
+ /* Does this symbol need an IPLT stub? */
+ unsigned int needs_iplt : 1;
+
+ /* Does this ifunc symbol need an IRELATIVE relocation? */
+ unsigned int needs_ireloc : 1;
};
/* MIPS ELF linker hash table. */
@@ -485,6 +502,9 @@ struct mips_elf_link_hash_table
/* The index of the next .got.plt entry to create. */
bfd_vma plt_got_index;
+ /* The size of an IPLT entry in bytes. */
+ bfd_vma iplt_entry_size;
+
/* The number of functions that need a lazy-binding stub. */
bfd_vma lazy_stub_count;
@@ -516,6 +536,10 @@ struct mips_elf_link_hash_table
/* Is the PLT header compressed? */
unsigned int plt_header_is_comp : 1;
+
+ /* Used by local STT_GNU_IFUNC symbols. */
+ htab_t loc_hash_table;
+ void *loc_hash_memory;
};
/* Get the MIPS ELF linker hash table from a link_info structure. */
@@ -800,6 +824,10 @@ static bfd *reldyn_sorting_bfd;
#define MICROMIPS_P(abfd) \
((elf_elfheader (abfd)->e_flags & EF_MIPS_ARCH_ASE_MICROMIPS) != 0)
+/* Nonzero if ABFD has mips16 code. */
+#define MIPS16_P(abfd) \
+ ((elf_elfheader (abfd)->e_flags & EF_MIPS_ARCH_ASE_M16) != 0)
+
/* Nonzero if ABFD is MIPS R6. */
#define MIPSR6_P(abfd) \
((elf_elfheader (abfd)->e_flags & EF_MIPS_ARCH) == E_MIPS_ARCH_32R6 \
@@ -1185,6 +1213,70 @@ static const bfd_vma mips_vxworks_shared_plt_entry[] =
0x10000000, /* b .PLT_resolver */
0x24180000 /* li t8, <pltindex> */
};
+
+/* The format of MIPS16 o32 IPLT entries. We use v0 ($2)
+ and v1 ($3) as temporaries because t8 ($24) and t9 ($25) are not
+ directly addressable. */
+static const bfd_vma mips16_exec_iplt_entry[] =
+{
+ 0xb202, /* lw $2, 8($pc) */
+ 0x9a60, /* lw $3, 0($2) */
+ 0xeb00, /* jr $3 */
+ 0x653b, /* move $25, $3 */
+ 0x0000, 0x0000 /* .word (.igot address) */
+};
+
+/* The format of 32 bit IPLT entries. */
+static const bfd_vma mips32_exec_iplt_entry[] =
+{
+ 0x3c0f0000, /* lui $15, %hi(.igot address) */
+ 0x8df90000, /* lw $25, %lo(.igot address)($15) */
+ 0x03200008, /* jr $25 */
+ 0x00000000 /* nop */
+};
+
+/* Format of 32 bit IPLT entries for R6. JR encoding differs. */
+static const bfd_vma mips32r6_exec_iplt_entry[] =
+{
+ 0x3c0f0000, /* lui $15, %hi(.igot address) */
+ 0x8df90000, /* lw $25, %lo(.igot address)($15) */
+ 0x03200009, /* jr $25 */
+ 0x00000000 /* nop */
+};
+
+/* The format of 32-bit micromips IPLT entries. */
+static const bfd_vma micromips32_exec_iplt_entry[] =
+{
+ 0x41a30000, /* lui $2, %hi(.igot address) */
+ 0xff230000, /* ld $2, %lo(.igot address)($2) */
+ 0x4599, /* jr $25 */
+ 0x0c00, /* nop */
+};
+
+/* The format of 64-bit IPLT entries. */
+static const bfd_vma mips64_exec_iplt_entry[] =
+{
+ 0x3c0f0000, /* lui $15, %highest(.got.iplt entry) */
+ 0x3c0e0000, /* lui $14, %hi(.got.iplt entry) */
+ 0x25ef0000, /* addiu $15, $15, %higher(.got.iplt entry) */
+ 0x000f783c, /* dsll32 $15, $15, 0x0 */
+ 0x01ee782d, /* daddu $15, $15, $14 */
+ 0xddf90000, /* ld $25, %lo(.got.iplt entry)($15) */
+ 0x03200008, /* jr $25 */
+ 0x00000000, /* nop */
+};
+
+/* The format of 64-bit IPLT entries for 48bit address. */
+static const bfd_vma mips64_48b_exec_iplt_entry[] =
+{
+ 0x3c0f0000, /* lui $15, %higher(.got.iplt entry) */
+ 0x25ef0000, /* addiu $15, $15, %high(.got.iplt entry) */
+ 0x000f7c38, /* dsll $15, $15, 16 */
+ 0xddf90000, /* ld $25, %lo(.got.iplt entry)($15) */
+ 0x03200008, /* jr $25 */
+ 0x00000000, /* nop */
+};
+
/* microMIPS 32-bit opcode helper installer. */
@@ -1283,6 +1375,10 @@ mips_elf_link_hash_newfunc (struct bfd_hash_entry *entry,
ret->has_nonpic_branches = FALSE;
ret->needs_lazy_stub = FALSE;
ret->use_plt_entry = FALSE;
+ ret->needs_iplt = FALSE;
+ ret->needs_ireloc = FALSE;
+ ret->iplt_offset = -1;
+ ret->igot_offset = 0;
}
return (struct bfd_hash_entry *) ret;
@@ -1582,7 +1678,8 @@ mips_elf_create_stub_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *elfh;
const char *name;
- if (ELF_ST_IS_MICROMIPS (h->root.other))
+ if (ELF_ST_IS_MICROMIPS (h->root.other)
+ || (ELF_ST_IS_MIPS16 (h->root.other) && h->root.type == STT_GNU_IFUNC))
value |= 1;
/* Create a new symbol. */
@@ -1598,6 +1695,10 @@ mips_elf_create_stub_symbol (struct bfd_link_info *info,
elfh->type = ELF_ST_INFO (STB_LOCAL, STT_FUNC);
elfh->size = size;
elfh->forced_local = 1;
+
+ if (ELF_ST_IS_MIPS16 (h->root.other) && h->needs_iplt)
+ elfh->other = STO_MIPS16;
+
return TRUE;
}
@@ -1960,6 +2061,136 @@ mips_elf_add_la25_stub (struct bfd_link_info *info,
: mips_elf_add_la25_intro (stub, info));
}
+/* Return the dynamic relocation section. If it doesn't exist, try to
+ create a new one if CREATE_P, otherwise return NULL. Also return NULL
+ if creation fails. */
+
+static asection *
+mips_elf_rel_dyn_section (struct bfd_link_info *info, bfd_boolean create_p)
+{
+ const char *dname;
+ asection *sreloc;
+ bfd *dynobj;
+
+ dname = MIPS_ELF_REL_DYN_NAME (info);
+ dynobj = elf_hash_table (info)->dynobj;
+ sreloc = bfd_get_linker_section (dynobj, dname);
+ if (sreloc == NULL && create_p)
+ {
+ sreloc = bfd_make_section_anyway_with_flags (dynobj, dname,
+ (SEC_ALLOC
+ | SEC_LOAD
+ | SEC_HAS_CONTENTS
+ | SEC_IN_MEMORY
+ | SEC_LINKER_CREATED
+ | SEC_READONLY));
+ if (sreloc == NULL
+ || !bfd_set_section_alignment (dynobj, sreloc,
+ MIPS_ELF_LOG_FILE_ALIGN (dynobj)))
+ return NULL;
+ }
+ return sreloc;
+}
+
+/* Return section for R_MIPS_IRELATIVE relocations. If the link is
+ dynamic, the relocations should go in .dynrel, otherwise they should
+ go in the special .rel.iplt section. */
+
+static asection *
+mips_get_irel_section (struct bfd_link_info *info,
+ struct mips_elf_link_hash_table *htab)
+{
+ asection *srel = (elf_hash_table (info)->dynamic_sections_created)
+ ? mips_elf_rel_dyn_section (info, FALSE)
+ : htab->root.irelplt;
+ BFD_ASSERT (srel != NULL);
+ return srel;
+}
+
+/* Reserve space in the rel.iplt section for IRELATIVE relocation. */
+
+static bfd_boolean
+mips_elf_allocate_ireloc (struct bfd_link_info *info,
+ struct mips_elf_link_hash_table *mhtab,
+ struct mips_elf_link_hash_entry *mh)
+{
+ asection *srel;
+ bfd *dynobj;
+
+ srel = mips_get_irel_section (info, mhtab);
+ dynobj = elf_hash_table (info)->dynobj;
+ if (srel != mhtab->root.irelplt && srel->size == 0)
+ {
+ /* Make room for a null element. */
+ srel->size += MIPS_ELF_REL_SIZE (dynobj);
+ ++srel->reloc_count;
+ }
+ srel->size += MIPS_ELF_REL_SIZE (dynobj);
+ mh->needs_ireloc = TRUE;
+
+ return TRUE;
+}
+
+/* Reserve space in the iplt and igot tables for an ifunc entry
+ and allocate space for an IRELATIVE relocation. */
+
+static bfd_boolean
+mips_elf_allocate_iplt (struct bfd_link_info *info,
+ struct mips_elf_link_hash_table *mhtab,
+ struct mips_elf_link_hash_entry *mh)
+{
+ asection *s;
+ bfd *abfd = info->output_bfd;
+
+ BFD_ASSERT (!mh->needs_iplt);
+ BFD_ASSERT (mhtab->root.iplt != NULL);
+
+ s = mhtab->root.iplt;
+
+ mh->iplt_offset = s->size;
+ mips_elf_create_stub_symbol (info, mh, ".iplt.", mhtab->root.iplt,
+ s->size, mhtab->iplt_entry_size);
+ s->size += mhtab->iplt_entry_size;
+
+ BFD_ASSERT (mhtab->root.igotplt != NULL);
+ mh->igot_offset = mhtab->root.igotplt->size;
+ mhtab->root.igotplt->size += MIPS_ELF_GOT_SIZE (abfd);
+ mh->needs_iplt = TRUE;
+
+ return TRUE;
+}
+
+/* hash_traverse callback that is called before sizing sections.
+ DATA points to a mips_htab_traverse_info structure. */
+
+static bfd_boolean
+mips_elf_check_local_symbols (void **slot, void *data)
+{
+ struct mips_htab_traverse_info *hti =
+ (struct mips_htab_traverse_info *) data;
+ struct mips_elf_link_hash_entry *h =
+ (struct mips_elf_link_hash_entry *) *slot;
+
+ /* If the referenced symbol is ifunc, allocate an iplt for it. */
+ if (h && !h->needs_iplt && h->root.type == STT_GNU_IFUNC
+ && h->root.def_regular)
+ {
+ struct bfd_link_info *info = hti->info;
+ elf_tdata (info->output_bfd)->has_gnu_symbols |= elf_gnu_symbol_ifunc;
+
+ /* .iplt entry is needed only for executable objects. */
+ if (!bfd_link_pic (info) &&
+ !mips_elf_allocate_iplt (info, mips_elf_hash_table (info), h))
+ return FALSE;
+
+ /* IRELATIVE fixup will be needed for each local IFUNC. */
+ if (!mips_elf_allocate_ireloc (info, mips_elf_hash_table (info), h))
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
/* A mips_elf_link_hash_traverse callback that is called before sizing
sections. DATA points to a mips_htab_traverse_info structure. */
@@ -1972,6 +2203,21 @@ mips_elf_check_symbols (struct mips_elf_link_hash_entry *h, void *data)
if (!bfd_link_relocatable (hti->info))
mips_elf_check_mips16_stubs (hti->info, h);
+ if (h && !h->needs_iplt && h->root.type == STT_GNU_IFUNC
+ && h->root.def_regular)
+ {
+ struct bfd_link_info *info = hti->info;
+ elf_tdata (info->output_bfd)->has_gnu_symbols |= elf_gnu_symbol_ifunc;
+
+ /* .iplt entry is needed only for executable objects. */
+ if (!bfd_link_pic (info)
+ && !mips_elf_allocate_iplt (info, mips_elf_hash_table (info), h))
+ return FALSE;
+ /* IREL or REL32 fixup is needed for each global IFUNC. */
+ if (!mips_elf_allocate_ireloc (info, mips_elf_hash_table (info), h))
+ return FALSE;
+ }
+
if (mips_elf_local_pic_function_p (h))
{
/* PR 12845: If H is in a section that has been garbage
@@ -3139,37 +3385,6 @@ mips_elf_replace_bfd_got (bfd *abfd, struct mips_got_info *g)
tdata->got = g;
}
-/* Return the dynamic relocation section. If it doesn't exist, try to
- create a new it if CREATE_P, otherwise return NULL. Also return NULL
- if creation fails. */
-
-static asection *
-mips_elf_rel_dyn_section (struct bfd_link_info *info, bfd_boolean create_p)
-{
- const char *dname;
- asection *sreloc;
- bfd *dynobj;
-
- dname = MIPS_ELF_REL_DYN_NAME (info);
- dynobj = elf_hash_table (info)->dynobj;
- sreloc = bfd_get_linker_section (dynobj, dname);
- if (sreloc == NULL && create_p)
- {
- sreloc = bfd_make_section_anyway_with_flags (dynobj, dname,
- (SEC_ALLOC
- | SEC_LOAD
- | SEC_HAS_CONTENTS
- | SEC_IN_MEMORY
- | SEC_LINKER_CREATED
- | SEC_READONLY));
- if (sreloc == NULL
- || ! bfd_set_section_alignment (dynobj, sreloc,
- MIPS_ELF_LOG_FILE_ALIGN (dynobj)))
- return NULL;
- }
- return sreloc;
-}
-
/* Return the GOT_TLS_* type required by relocation type R_TYPE. */
static int
@@ -3263,9 +3478,12 @@ mips_elf_count_got_entry (struct bfd_link_info *info,
entry->symndx < 0
? &entry->d.h->root : NULL);
}
- else if (entry->symndx >= 0 || entry->d.h->global_got_area == GGA_NONE)
+ /* Skip IFUNCs from local/global GOT, they are already counted as general
+ GOT entries with explicit relocations. */
+ else if (entry->symndx >= 0 || (entry->d.h->global_got_area == GGA_NONE
+ && !entry->d.h->needs_ireloc))
g->local_gotno += 1;
- else
+ else if (!entry->d.h->needs_ireloc)
g->global_gotno += 1;
}
@@ -3596,7 +3814,8 @@ mips_elf_got_page (bfd *abfd, bfd *ibfd, struct bfd_link_info *info,
static bfd_vma
mips_elf_got16_entry (bfd *abfd, bfd *ibfd, struct bfd_link_info *info,
- bfd_vma value, bfd_boolean external)
+ bfd_vma value, bfd_boolean external,
+ struct mips_elf_link_hash_entry *h)
{
struct mips_got_entry *entry;
@@ -3611,7 +3830,7 @@ mips_elf_got16_entry (bfd *abfd, bfd *ibfd, struct bfd_link_info *info,
R_MIPS16_GOT16, R_MIPS_CALL16, etc. The format of the entry is the
same in all cases. */
entry = mips_elf_create_local_got_entry (abfd, info, ibfd, value, 0,
- NULL, R_MIPS_GOT16);
+ h, R_MIPS_GOT16);
if (entry)
return entry->gotidx;
else
@@ -3711,7 +3930,8 @@ mips_elf_create_local_got_entry (bfd *abfd, struct bfd_link_info *info,
if (entry)
return entry;
- if (g->assigned_low_gotno > g->assigned_high_gotno)
+ if (g->assigned_low_gotno > g->assigned_high_gotno ||
+ g->assigned_general_gotno > g->assigned_low_gotno)
{
/* We didn't allocate enough space in the GOT. */
(*_bfd_error_handler)
@@ -3724,7 +3944,11 @@ mips_elf_create_local_got_entry (bfd *abfd, struct bfd_link_info *info,
if (!entry)
return NULL;
- if (got16_reloc_p (r_type)
+ if (h && h->needs_ireloc)
+ /* Allocate IFUNC slots in the general GOT region since they
+ will need explicit IRELATIVE relocations. */
+ lookup.gotidx = MIPS_ELF_GOT_SIZE (abfd) * g->assigned_general_gotno++;
+ else if (got16_reloc_p (r_type)
|| call16_reloc_p (r_type)
|| got_page_reloc_p (r_type)
|| got_disp_reloc_p (r_type))
@@ -3952,7 +4176,11 @@ mips_elf_record_global_got_symbol (struct elf_link_hash_entry *h,
}
tls_type = mips_elf_reloc_tls_type (r_type);
- if (tls_type == GOT_TLS_NONE && hmips->global_got_area > GGA_NORMAL)
+ /* IFUNC symbols use explicitly relocated GOT region, instead of the ABI
+ global GOT, but we don't distinguish these from the local GOT region
+ just yet. */
+ if (tls_type == GOT_TLS_NONE && hmips->global_got_area > GGA_NORMAL
+ && !hmips->needs_ireloc)
hmips->global_got_area = GGA_NORMAL;
entry.abfd = abfd;
@@ -4398,7 +4626,9 @@ mips_use_local_got_p (struct bfd_link_info *info,
local GOT. This includes symbols that are completely undefined
and which therefore don't bind locally. We'll report undefined
symbols later if appropriate. */
- if (h->root.dynindx == -1)
+ /* Both global & local IFUNC symbols actually use the explicitly relocated
+ GOT region, but we don't distinguish it from local GOT just yet. */
+ if (h->root.dynindx == -1 || h->needs_ireloc)
return TRUE;
/* Symbols that bind locally can (and in the case of forced-local
@@ -4455,6 +4685,33 @@ mips_elf_count_got_symbols (struct mips_elf_link_hash_entry *h, void *data)
g->global_gotno++;
}
}
+
+ if (h->needs_ireloc)
+ /* Count IFUNCs towards explicitly relocated GOT. */
+ g->general_gotno++;
+
+ return 1;
+}
+
+/* A elf_link_hash_traverse callback for which INF points to the
+ link_info structure. Count the number of GOT entries that need
+ explicit relocations by iterating over the local hash table. */
+
+static int
+mips_elf_count_general_got_symbols (void **slot, void *inf)
+{
+ struct mips_elf_link_hash_entry *h =
+ (struct mips_elf_link_hash_entry *) *slot;
+ struct bfd_link_info *info;
+ struct mips_elf_link_hash_table *htab;
+ struct mips_got_info *g;
+
+ info = (struct bfd_link_info *) inf;
+ htab = mips_elf_hash_table (info);
+
+ g = htab->got_info;
+ if (h != NULL && h->needs_ireloc)
+ g->general_gotno++;
return 1;
}
@@ -5084,6 +5341,64 @@ mips_elf_create_compact_rel_section
return TRUE;
}
+/* Create the .iplt, .rel(a).iplt and .igot sections. */
+
+static bfd_boolean
+mips_elf_create_ifunc_sections (struct bfd_link_info *info)
+{
+ struct mips_elf_link_hash_table * volatile htab;
+ const struct elf_backend_data *bed;
+ bfd *dynobj;
+ asection *s;
+ flagword flags;
+
+ htab = mips_elf_hash_table (info);
+ dynobj = htab->root.dynobj;
+ bed = get_elf_backend_data (dynobj);
+ flags = bed->dynamic_sec_flags;
+
+ s = bfd_make_section_anyway_with_flags (dynobj, ".iplt",
+ flags | SEC_READONLY | SEC_CODE);
+ if (s == NULL || !bfd_set_section_alignment (dynobj, s, bed->plt_alignment))
+ return FALSE;
+
+ htab->root.iplt = s;
+
+ if (!bfd_link_pic (info))
+ {
+ if (ABI_64_P (dynobj))
+ htab->iplt_entry_size = 4 * ARRAY_SIZE (mips64_exec_iplt_entry);
+ else if (MIPS16_P (dynobj))
+ htab->iplt_entry_size = 2 * ARRAY_SIZE (mips16_exec_iplt_entry);
+ else if (MICROMIPS_P (dynobj))
+ /* Multiply by compression ratio for micromips. */
+ htab->iplt_entry_size = 4
+ * (ARRAY_SIZE (micromips32_exec_iplt_entry) * 3 / 4);
+ else
+ htab->iplt_entry_size = 4 * (ARRAY_SIZE (mips32_exec_iplt_entry)
+ + (LOAD_INTERLOCKS_P (dynobj)? 0 : 1));
+ }
+
+ BFD_ASSERT (htab->root.igotplt == NULL);
+
+ s = bfd_make_section_anyway_with_flags (dynobj, ".igot", flags);
+ if (s == NULL
+ || !bfd_set_section_alignment (dynobj, s, bed->s->log_file_align))
+ return FALSE;
+ htab->root.igotplt = s;
+ mips_elf_section_data (s)->elf.this_hdr.sh_flags |= SHF_ALLOC | SHF_WRITE;
+
+ BFD_ASSERT (htab->root.irelplt == NULL);
+
+ s = bfd_make_section_with_flags (dynobj, ".rel.iplt", flags | SEC_READONLY);
+ if (s == NULL
+ || !bfd_set_section_alignment (dynobj, s, bed->s->log_file_align))
+ return FALSE;
+
+ htab->root.irelplt = s;
+ return TRUE;
+}
+
/* Create the .got section to hold the global offset table. */
static bfd_boolean
@@ -5200,6 +5515,75 @@ mips_elf_relocation_needs_la25_stub (bfd *input_bfd, int r_type,
return FALSE;
}
}
+
+/* Find and/or create a hash entry for local symbol. */
+
+static struct mips_elf_link_hash_entry *
+get_local_sym_hash (struct mips_elf_link_hash_table *htab,
+ bfd *abfd, const Elf_Internal_Rela *rel)
+{
+ struct mips_elf_link_hash_entry e, *ret;
+ asection *sec;
+ hashval_t h;
+ void **slot;
+ Elf_Internal_Sym *isym;
+ Elf_Internal_Shdr *symtab_hdr;
+ char *namep;
+
+ sec = bfd_get_section_by_name (abfd, ".text");
+ h = ELF_LOCAL_SYMBOL_HASH (sec->id, ELF_R_SYM (abfd, rel->r_info));
+ isym = bfd_sym_from_r_symndx (&htab->sym_cache, abfd,
+ ELF_R_SYM (abfd, rel->r_info));
+ symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
+ namep = bfd_elf_string_from_elf_section (abfd, symtab_hdr->sh_link,
+ isym->st_name);
+
+ e.root.indx = sec->id;
+ e.root.dynstr_index = ELF_R_SYM (abfd, rel->r_info);
+ e.root.root.root.string = namep;
+
+ slot = htab_find_slot_with_hash (htab->loc_hash_table, &e, h, INSERT);
+ if (!slot)
+ return NULL;
+
+ /* Found match. */
+ if (*slot)
+ {
+ ret = (struct mips_elf_link_hash_entry *) *slot;
+ return ret;
+ }
+
+ /* Allocate new slot. */
+ ret = (struct mips_elf_link_hash_entry *)
+ objalloc_alloc ((struct objalloc *) htab->loc_hash_memory,
+ sizeof (struct mips_elf_link_hash_entry));
+
+ if (ret)
+ {
+ memset (ret, 0, sizeof (*ret));
+ ret->root.indx = sec->id;
+ ret->root.dynstr_index = ELF_R_SYM (abfd, rel->r_info);
+ ret->root.dynindx = -1;
+ ret->root.root.root.string = namep;
+ ret->root.root.u.def.section = sec;
+ ret->root.root.u.def.value = isym->st_value;
+ ret->root.got.offset = (bfd_vma) -1;
+ ret->global_got_area = GGA_NONE;
+ ret->root.type = STT_GNU_IFUNC;
+ ret->root.def_regular = 1;
+ ret->root.ref_regular = 1;
+ ret->root.forced_local = 1;
+ ret->root.root.type = bfd_link_hash_defined;
+ if (MIPS16_P (abfd))
+ ret->root.other = STO_MIPS16;
+ if (MICROMIPS_P (abfd))
+ ret->root.other = STO_MICROMIPS;
+
+ *slot = ret;
+ }
+
+ return ret;
+}
/* Calculate the value produced by the RELOCATION (which comes from
the INPUT_BFD). The ADDEND is the addend to use for this
@@ -5250,6 +5634,8 @@ mips_elf_calculate_relocation (bfd *abfd, bfd *input_bfd,
/* TRUE if the symbol referred to by this relocation is a local
symbol. */
bfd_boolean local_p, was_local_p;
+ /* TRUE if the symbol referred to by this relocation is a local IFUNC. */
+ bfd_boolean local_gnu_ifunc_p = FALSE;
/* TRUE if the symbol referred to by this relocation is "_gp_disp". */
bfd_boolean gp_disp_p = FALSE;
/* TRUE if the symbol referred to by this relocation is
@@ -5330,6 +5716,13 @@ mips_elf_calculate_relocation (bfd *abfd, bfd *input_bfd,
target_is_16_bit_code_p = ELF_ST_IS_MIPS16 (sym->st_other);
target_is_micromips_code_p = ELF_ST_IS_MICROMIPS (sym->st_other);
+
+ if (sym->st_info == STT_GNU_IFUNC)
+ {
+ h = get_local_sym_hash (mips_elf_hash_table (info), input_bfd,
+ relocation);
+ local_gnu_ifunc_p = TRUE;
+ }
}
else
{
@@ -5554,6 +5947,17 @@ mips_elf_calculate_relocation (bfd *abfd, bfd *input_bfd,
target_is_16_bit_code_p = !micromips_p;
target_is_micromips_code_p = micromips_p;
}
+ /* If this symbol is an ifunc, point to the iplt stub for it. */
+ else if (h && h->needs_iplt)
+ {
+ BFD_ASSERT (htab->root.iplt != NULL);
+ symbol = (htab->root.iplt->output_section->vma
+ + htab->root.iplt->output_offset
+ + h->iplt_offset);
+ /* Set ISA bit in address for compressed code. */
+ if (ELF_ST_IS_COMPRESSED (h->root.other))
+ symbol |= 1;
+ }
/* Make sure MIPS16 and microMIPS are not used together. */
if ((r_type == R_MIPS16_26 && target_is_micromips_code_p)
@@ -5649,6 +6053,16 @@ mips_elf_calculate_relocation (bfd *abfd, bfd *input_bfd,
BFD_ASSERT (h->root.needs_plt);
g = mips_elf_gotplt_index (info, &h->root);
}
+ /* IFUNCs use explicit GOT, however we don't distinguish it
+ from local GOT at this stage. */
+ else if (h && h->needs_ireloc && !h->needs_iplt)
+ {
+ g = mips_elf_local_got_index (abfd, input_bfd, info,
+ symbol + addend, r_symndx,
+ h, r_type);
+ if (g == MINUS_ONE)
+ return bfd_reloc_outofrange;
+ }
else
{
BFD_ASSERT (addend == 0);
@@ -5940,8 +6354,11 @@ mips_elf_calculate_relocation (bfd *abfd, bfd *input_bfd,
R_MIPS*_GOT16; every relocation evaluates to "G". */
if (!htab->is_vxworks && local_p)
{
+ /* Local IFUNC symbols must be accessed through GOT, similar to
+ global symbols, to allow for indirection. */
value = mips_elf_got16_entry (abfd, input_bfd, info,
- symbol + addend, !was_local_p);
+ symbol + addend,
+ !was_local_p || local_gnu_ifunc_p, h);
if (value == MINUS_ONE)
return bfd_reloc_outofrange;
value
@@ -6386,7 +6803,8 @@ mips_elf_create_dynamic_relocation (bfd *output_bfd,
in the relocation. */
if (h != NULL && ! SYMBOL_REFERENCES_LOCAL (info, &h->root))
{
- BFD_ASSERT (htab->is_vxworks || h->global_got_area != GGA_NONE);
+ BFD_ASSERT (htab->is_vxworks || h->global_got_area != GGA_NONE
+ || h->root.type == STT_GNU_IFUNC);
indx = h->root.dynindx;
if (SGI_COMPAT (output_bfd))
defined_p = h->root.def_regular;
@@ -6445,31 +6863,42 @@ mips_elf_create_dynamic_relocation (bfd *output_bfd,
if (defined_p && r_type != R_MIPS_REL32)
*addendp += symbol;
- if (htab->is_vxworks)
- /* VxWorks uses non-relative relocations for this. */
- outrel[0].r_info = ELF32_R_INFO (indx, R_MIPS_32);
+ /* Morph REL32 in to IRELATIVE fix-up for local IFUNC reference. */
+ if (h && !indx && h->root.type == STT_GNU_IFUNC)
+ {
+ outrel[0].r_info = ELF_R_INFO (output_bfd, (unsigned long) indx,
+ R_MIPS_IRELATIVE);
+ outrel[1].r_info = ELF_R_INFO (output_bfd, 0,
+ R_MIPS_NONE);
+ }
else
- /* The relocation is always an REL32 relocation because we don't
- know where the shared library will wind up at load-time. */
- outrel[0].r_info = ELF_R_INFO (output_bfd, (unsigned long) indx,
- R_MIPS_REL32);
-
- /* For strict adherence to the ABI specification, we should
- generate a R_MIPS_64 relocation record by itself before the
- _REL32/_64 record as well, such that the addend is read in as
- a 64-bit value (REL32 is a 32-bit relocation, after all).
- However, since none of the existing ELF64 MIPS dynamic
- loaders seems to care, we don't waste space with these
- artificial relocations. If this turns out to not be true,
- mips_elf_allocate_dynamic_relocation() should be tweaked so
- as to make room for a pair of dynamic relocations per
- invocation if ABI_64_P, and here we should generate an
- additional relocation record with R_MIPS_64 by itself for a
- NULL symbol before this relocation record. */
- outrel[1].r_info = ELF_R_INFO (output_bfd, 0,
- ABI_64_P (output_bfd)
- ? R_MIPS_64
- : R_MIPS_NONE);
+ {
+ if (htab->is_vxworks)
+ /* VxWorks uses non-relative relocations for this. */
+ outrel[0].r_info = ELF32_R_INFO (indx, R_MIPS_32);
+ else
+ /* The relocation is always an REL32 relocation because we don't
+ know where the shared library will wind up at load-time. */
+ outrel[0].r_info = ELF_R_INFO (output_bfd, (unsigned long) indx,
+ R_MIPS_REL32);
+
+ /* For strict adherence to the ABI specification, we should
+ generate a R_MIPS_64 relocation record by itself before the
+ _REL32/_64 record as well, such that the addend is read in as
+ a 64-bit value (REL32 is a 32-bit relocation, after all).
+ However, since none of the existing ELF64 MIPS dynamic
+ loaders seems to care, we don't waste space with these
+ artificial relocations. If this turns out to not be true,
+ mips_elf_allocate_dynamic_relocation() should be tweaked so
+ as to make room for a pair of dynamic relocations per
+ invocation if ABI_64_P, and here we should generate an
+ additional relocation record with R_MIPS_64 by itself for a
+ NULL symbol before this relocation record. */
+ outrel[1].r_info = ELF_R_INFO (output_bfd, 0,
+ ABI_64_P (output_bfd)
+ ? R_MIPS_64
+ : R_MIPS_NONE);
+ }
outrel[2].r_info = ELF_R_INFO (output_bfd, 0, R_MIPS_NONE);
/* Adjust the output offset of the relocation to reference the
@@ -7016,6 +7445,8 @@ _bfd_mips_elf_section_processing (bfd *abfd, Elf_Internal_Shdr *hdr)
hdr->sh_size += hdr->sh_addralign - adjust;
}
}
+ else if (strcmp (name, ".igot") == 0)
+ hdr->sh_entsize = MIPS_ELF_GOT_SIZE (abfd);
}
return TRUE;
@@ -7929,6 +8360,13 @@ _bfd_mips_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
bed = get_elf_backend_data (abfd);
rel_end = relocs + sec->reloc_count * bed->s->int_rels_per_ext_rel;
+ /* This needs to happen early. If the sections aren't needed
+ they will not get generated. */
+ if (htab->root.dynobj == NULL)
+ htab->root.dynobj = abfd;
+ if (!htab->root.iplt && !mips_elf_create_ifunc_sections (info))
+ return FALSE;
+
/* Check for the mips16 stub sections. */
name = bfd_get_section_name (abfd, sec);
@@ -8190,12 +8628,30 @@ _bfd_mips_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
bfd_boolean can_make_dynamic_p;
bfd_boolean call_reloc_p;
bfd_boolean constrain_symbol_p;
+ bfd_boolean local_gnu_ifunc_p = FALSE;
r_symndx = ELF_R_SYM (abfd, rel->r_info);
r_type = ELF_R_TYPE (abfd, rel->r_info);
if (r_symndx < extsymoff)
- h = NULL;
+ {
+ Elf_Internal_Sym *isym;
+ isym = bfd_sym_from_r_symndx (&htab->sym_cache, abfd, r_symndx);
+
+ if (isym == NULL)
+ return FALSE;
+
+ /* Relocation is for local STT_GNU_IFUNC symbol. */
+ if (isym->st_info == STT_GNU_IFUNC)
+ {
+ /* Ensure that we have a hash entry for this symbol. */
+ if (get_local_sym_hash (htab, abfd, rel) == NULL)
+ return FALSE;
+ local_gnu_ifunc_p = TRUE;
+ }
+
+ h = NULL;
+ }
else if (r_symndx >= extsymoff + NUM_SHDR_ENTRIES (symtab_hdr))
{
(*_bfd_error_handler)
@@ -8407,7 +8863,8 @@ _bfd_mips_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
case R_MIPS_CALL16:
case R_MIPS16_CALL16:
case R_MICROMIPS_CALL16:
- if (h == NULL)
+ /* Exclude local IFUNCs from check. */
+ if (h == NULL && !local_gnu_ifunc_p)
{
(*_bfd_error_handler)
(_("%B: CALL16 reloc at 0x%lx not against global symbol"),
@@ -8432,9 +8889,11 @@ _bfd_mips_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
/* We need a stub, not a plt entry for the undefined
function. But we record it as if it needs plt. See
- _bfd_elf_adjust_dynamic_symbol. */
+ _bfd_elf_adjust_dynamic_symbol. If it is an ifunc
+ symbol it will go into an iplt section and not plt. */
h->needs_plt = 1;
- h->type = STT_FUNC;
+ if (h->type != STT_GNU_IFUNC)
+ h->type = STT_FUNC;
}
break;
@@ -8973,6 +9432,7 @@ _bfd_mips_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
/* Make sure we know what is going on here. */
BFD_ASSERT (dynobj != NULL
&& (h->needs_plt
+ || h->type == STT_GNU_IFUNC
|| h->u.weakdef != NULL
|| (h->def_dynamic
&& h->ref_regular
@@ -9251,6 +9711,10 @@ _bfd_mips_elf_always_size_sections (bfd *output_bfd,
hti.error = FALSE;
mips_elf_link_hash_traverse (mips_elf_hash_table (info),
mips_elf_check_symbols, &hti);
+
+ /* Allocate relocs for local IFUNC symbols. */
+ htab_traverse (htab->loc_hash_table, mips_elf_check_local_symbols, &hti);
+
if (hti.error)
return FALSE;
@@ -9295,9 +9759,17 @@ mips_elf_lay_out_got (bfd *output_bfd, struct bfd_link_info *info)
count the number of reloc-only GOT symbols. */
mips_elf_link_hash_traverse (htab, mips_elf_count_got_symbols, info);
+ /* Count local IFUNC symbols. These need general GOT entries that
+ are fixed-up by explicit IRELATIVE relocations. */
+ htab_traverse (htab->loc_hash_table, mips_elf_count_general_got_symbols, info);
+
if (!mips_elf_resolve_final_got_entries (info, g))
return FALSE;
+ g->assigned_general_gotno = htab->reserved_gotno;
+ g->local_gotno += g->general_gotno;
+ g->assigned_low_gotno += g->general_gotno;
+
/* Calculate the total loadable size of the output. That
will give us the maximum number of GOT_PAGE entries
required. */
@@ -9739,6 +10211,8 @@ _bfd_mips_elf_size_dynamic_sections (bfd *output_bfd,
else if (! CONST_STRNEQ (name, ".init")
&& s != htab->sgot
&& s != htab->sgotplt
+ && s != htab->root.iplt
+ && s != htab->root.igotplt
&& s != htab->sstubs
&& s != htab->sdynbss)
{
@@ -9884,6 +10358,13 @@ _bfd_mips_elf_size_dynamic_sections (bfd *output_bfd,
if (! MIPS_ELF_ADD_DYNAMIC_ENTRY (info, DT_MIPS_PLTGOT, 0))
return FALSE;
}
+
+ if (htab->got_info->general_gotno > 0)
+ {
+ if (! MIPS_ELF_ADD_DYNAMIC_ENTRY (info, DT_MIPS_GENERAL_GOTNO, 0))
+ return FALSE;
+ }
+
if (htab->is_vxworks
&& !elf_vxworks_add_dynamic_entries (output_bfd, info))
return FALSE;
@@ -10015,6 +10496,7 @@ _bfd_mips_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
Elf_Internal_Shdr *symtab_hdr;
struct elf_link_hash_entry *h;
bfd_boolean rel_reloc;
+ bfd_boolean local_gnu_ifunc_p = FALSE;
rel_reloc = (NEWABI_P (input_bfd)
&& mips_elf_rel_relocation_p (input_bfd, input_section,
@@ -10028,6 +10510,23 @@ _bfd_mips_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
{
sec = local_sections[r_symndx];
h = NULL;
+
+ Elf_Internal_Sym *isym;
+ struct mips_elf_link_hash_table *htab;
+ htab = mips_elf_hash_table (info);
+ isym = bfd_sym_from_r_symndx (&htab->sym_cache, input_bfd, r_symndx);
+
+ if (isym == NULL)
+ return FALSE;
+
+ /* Relocation is for local STT_GNU_IFUNC symbol. */
+ if (isym->st_info == STT_GNU_IFUNC)
+ {
+ /* Ensure that we have a hash entry for this symbol. */
+ if (get_local_sym_hash (htab, input_bfd, rel) == NULL)
+ return FALSE;
+ local_gnu_ifunc_p = TRUE;
+ }
}
else
{
@@ -10088,8 +10587,9 @@ _bfd_mips_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
&& mips_elf_local_relocation_p (input_bfd, rel,
local_sections)))
{
- if (!mips_elf_add_lo16_rel_addend (input_bfd, rel, relend,
- contents, &addend))
+ if (!local_gnu_ifunc_p
+ && !mips_elf_add_lo16_rel_addend (input_bfd, rel, relend,
+ contents, &addend))
{
if (h)
name = h->root.root.string;
@@ -10476,6 +10976,265 @@ mips_elf_irix6_finish_dynamic_symbol (bfd *abfd ATTRIBUTE_UNUSED,
}
}
+/* Create the contents of the iplt entry for an IFUNC symbol. */
+
+static bfd_boolean
+mips_elf_create_iplt (bfd *output_bfd,
+ struct mips_elf_link_hash_table *htab,
+ struct mips_elf_link_hash_entry *hmips,
+ bfd_vma igotplt_address)
+{
+ bfd_byte *loc;
+ const bfd_vma *iplt_entry;
+ bfd_vma high = mips_elf_high (igotplt_address);
+ bfd_vma low = igotplt_address & 0xffff;
+
+ /* Find out where the .iplt entry should go. */
+ if (!htab->root.iplt->contents)
+ {
+ htab->root.iplt->contents = bfd_zalloc (output_bfd,
+ htab->root.iplt->size);
+ if (!htab->root.iplt->contents)
+ return FALSE;
+ }
+ loc = htab->root.iplt->contents + hmips->iplt_offset;
+
+ /* Fill in the IPLT entry itself. */
+ if (ABI_64_P (output_bfd))
+ {
+ bfd_vma highest = mips_elf_highest (igotplt_address);
+ bfd_vma higher = mips_elf_higher (igotplt_address);
+ iplt_entry = mips64_exec_iplt_entry;
+
+ if (highest)
+ {
+ /* Full 64-bit address space. */
+ bfd_put_32 (output_bfd, iplt_entry[0] | highest, loc);
+ bfd_put_32 (output_bfd, iplt_entry[1] | high, loc + 4);
+ bfd_put_32 (output_bfd, iplt_entry[2] | higher, loc + 8);
+ bfd_put_32 (output_bfd, iplt_entry[3], loc + 12);
+ bfd_put_32 (output_bfd, iplt_entry[4], loc + 16);
+ bfd_put_32 (output_bfd, iplt_entry[5] | low, loc + 20);
+ bfd_put_32 (output_bfd, iplt_entry[6], loc + 24);
+ bfd_put_32 (output_bfd, iplt_entry[7], loc + 28);
+ }
+ else if (higher)
+ {
+ /* 48-bit address space. */
+ iplt_entry = mips64_48b_exec_iplt_entry;
+ bfd_put_32 (output_bfd, iplt_entry[0] | higher, loc);
+ bfd_put_32 (output_bfd, iplt_entry[1] | high, loc + 4);
+ bfd_put_32 (output_bfd, iplt_entry[2], loc + 8);
+ bfd_put_32 (output_bfd, iplt_entry[3] | low, loc + 12);
+ bfd_put_32 (output_bfd, iplt_entry[4], loc + 16);
+ bfd_put_32 (output_bfd, iplt_entry[5], loc + 20);
+ }
+ else
+ {
+ /* 32-bit address space. */
+ bfd_put_32 (output_bfd, iplt_entry[0] | high, loc);
+ bfd_put_32 (output_bfd, iplt_entry[5] | low, loc + 4);
+ bfd_put_32 (output_bfd, iplt_entry[6], loc + 8);
+ bfd_put_32 (output_bfd, iplt_entry[7], loc + 12);
+ }
+ }
+ else if (ELF_ST_IS_MIPS16 (hmips->root.other))
+ {
+ iplt_entry = mips16_exec_iplt_entry;
+ bfd_put_16 (output_bfd, iplt_entry[0], loc);
+ bfd_put_16 (output_bfd, iplt_entry[1], loc + 2);
+ bfd_put_16 (output_bfd, iplt_entry[2], loc + 4);
+ bfd_put_16 (output_bfd, iplt_entry[3], loc + 6);
+ bfd_put_32 (output_bfd, igotplt_address, loc + 8);
+ }
+ else if (ELF_ST_IS_MICROMIPS (hmips->root.other))
+ {
+ iplt_entry = micromips32_exec_iplt_entry;
+ bfd_put_micromips_32 (output_bfd, iplt_entry[0] | high, loc);
+ bfd_put_micromips_32 (output_bfd, iplt_entry[1] | low , loc + 4);
+
+ bfd_put_16 (output_bfd, iplt_entry[2], loc + 8);
+ bfd_put_16 (output_bfd, iplt_entry[3], loc + 10);
+ }
+ else
+ {
+ if (MIPSR6_P(output_bfd))
+ iplt_entry = mips32r6_exec_iplt_entry;
+ else
+ iplt_entry = mips32_exec_iplt_entry;
+ bfd_put_32 (output_bfd, iplt_entry[0] | high, loc);
+ bfd_put_32 (output_bfd, iplt_entry[1] | low, loc + 4);
+ if (LOAD_INTERLOCKS_P (output_bfd))
+ {
+ bfd_put_32 (output_bfd, iplt_entry[2], loc + 8);
+ bfd_put_32 (output_bfd, iplt_entry[3], loc + 12);
+ }
+ else
+ {
+ bfd_put_32 (output_bfd, iplt_entry[3], loc + 8);
+ bfd_put_32 (output_bfd, iplt_entry[2], loc + 12);
+ bfd_put_32 (output_bfd, iplt_entry[3], loc + 16);
+ }
+ }
+
+ return TRUE;
+}
+
+/* Find local GOT index for VALUE. Return -1 if no GOT slot is found. */
+
+static bfd_vma
+mips_elf_check_local_got_index (bfd *abfd, struct bfd_link_info *info,
+ struct mips_elf_link_hash_entry *h,
+ bfd_vma value)
+{
+ struct mips_got_entry lookup, *entry;
+ void **loc;
+ struct mips_got_info *g;
+ struct mips_elf_link_hash_table *htab;
+
+ htab = mips_elf_hash_table (info);
+ BFD_ASSERT (htab != NULL);
+
+ g = mips_elf_bfd_got (abfd, FALSE);
+ BFD_ASSERT (g != NULL);
+
+ /* Check for existing local GOT entry. */
+ lookup.abfd = NULL;
+ lookup.symndx = -1;
+ lookup.d.address = value;
+ lookup.tls_type = GOT_TLS_NONE;
+ loc = htab_find_slot (g->got_entries, &lookup, NO_INSERT);
+
+ if (loc && *loc)
+ entry = (struct mips_got_entry *) *loc;
+ else
+ {
+ /* Need to create and initialize a new GOT entry. We only get here
+ global IFUNC symbol and we need distinct hashes entries for aliased
+ symbols. */
+ lookup.symndx = h->root.dynindx;
+ lookup.abfd = abfd;
+ if (h->root.dynindx < 0)
+ lookup.d.h = h;
+ loc = htab_find_slot (g->got_entries, &lookup, INSERT);
+
+ if (!loc)
+ return -1;
+
+ entry = (struct mips_got_entry *) bfd_alloc (abfd, sizeof (*entry));
+ if (!entry)
+ return -1;
+
+ lookup.gotidx = MIPS_ELF_GOT_SIZE (abfd) * g->assigned_general_gotno++;
+ *entry = lookup;
+ *loc = entry;
+ MIPS_ELF_PUT_WORD (abfd, value, htab->sgot->contents + entry->gotidx);
+ }
+
+ return entry->gotidx;
+}
+
+/* Create the IRELATIVE relocation for an IFUNC symbol. */
+
+static bfd_boolean
+mips_elf_create_ireloc (bfd *output_bfd,
+ bfd *dynobj,
+ struct mips_elf_link_hash_table *htab,
+ struct mips_elf_link_hash_entry *hmips,
+ Elf_Internal_Sym *sym,
+ struct bfd_link_info *info)
+{
+ bfd_vma igotplt_address = 0;
+ int igot_offset = -1;
+ asection *gotsect, *relsect;
+ bfd_vma value = sym->st_value;
+
+ if (MIPS16_P (output_bfd) || MICROMIPS_P (output_bfd))
+ value |= 1;
+
+ if (!hmips->needs_iplt)
+ {
+ gotsect = htab->sgot;
+ /* Check if IFUNC symbol already has an assigned GOT slots; assign
+ a new slot if necessary. */
+ igot_offset = mips_elf_check_local_got_index (output_bfd, info,
+ hmips, value);
+ if (igot_offset < 0)
+ igot_offset = mips_elf_local_got_index (output_bfd, output_bfd, info,
+ value, hmips->root.dynindx,
+ hmips, R_MIPS_REL32);
+ }
+ else
+ {
+ bfd_byte *loc;
+ bfd_vma igot_index;
+ gotsect = htab->root.igotplt;
+ igot_offset = hmips->igot_offset;
+
+ /* Calculate the address of the IGOT entry. */
+ igot_index = igot_offset / MIPS_ELF_GOT_SIZE (dynobj);
+
+ if (!gotsect->contents)
+ {
+ gotsect->contents = bfd_zalloc (output_bfd, gotsect->size);
+ if (!gotsect->contents)
+ return FALSE;
+ }
+
+ /* Initially point the .igot entry at the IFUNC resolver routine. */
+ loc = (bfd_byte *) gotsect->contents
+ + igot_index * MIPS_ELF_GOT_SIZE (dynobj);
+
+ if (ABI_64_P (output_bfd))
+ bfd_put_64 (output_bfd, value, loc);
+ else
+ bfd_put_32 (output_bfd, value, loc);
+ }
+
+ igotplt_address = (gotsect->output_section->vma + gotsect->output_offset
+ + igot_offset);
+
+ relsect = mips_get_irel_section (info, htab);
+
+ if (igot_offset >= 0)
+ {
+ if (hmips->needs_iplt && relsect->contents == NULL)
+ {
+ /* Allocate memory for the relocation section contents. */
+ relsect->contents = bfd_zalloc (dynobj, relsect->size);
+ if (relsect->contents == NULL)
+ return FALSE;
+ }
+
+ if (hmips->needs_iplt || hmips->root.dynindx < 0)
+ /* Emit an R_MIPS_IRELATIVE relocation against the [I]GOT entry. */
+ mips_elf_output_dynamic_relocation (output_bfd, relsect,
+ relsect->reloc_count++, 0,
+ R_MIPS_IRELATIVE, igotplt_address);
+ else
+ {
+ /* Emit an R_MIPS_REL32 relocation against global GOT entry for
+ a preemptible symbol. */
+ asection *sec = hmips->root.root.u.def.section;
+ Elf_Internal_Rela rel[3];
+
+ memset (rel, 0, sizeof (rel));
+ rel[0].r_info = ELF_R_INFO (output_bfd, 0, R_MIPS_REL32);
+ rel[0].r_offset = rel[1].r_offset = rel[2].r_offset = igot_offset;
+
+ mips_elf_create_dynamic_relocation (output_bfd, info, rel, hmips,
+ sec, value, NULL,
+ gotsect);
+ }
+ }
+ /* If necessary, generate the corresponding .iplt entry. */
+ if (hmips->needs_iplt
+ && !mips_elf_create_iplt (output_bfd, htab, hmips, igotplt_address))
+ return FALSE;
+
+ return TRUE;
+}
+
/* Finish up dynamic symbol handling. We set the contents of various
dynamic sections here. */
@@ -10803,6 +11562,19 @@ _bfd_mips_elf_finish_dynamic_symbol (bfd *output_bfd,
sym->st_other = other;
}
+ if (hmips->root.type == STT_GNU_IFUNC)
+ {
+ if (hmips->needs_ireloc
+ && !mips_elf_create_ireloc (output_bfd, dynobj, htab,
+ hmips, sym, info))
+ return FALSE;
+
+ if (!elf_hash_table (info)->dynamic_sections_created)
+ return TRUE;
+ if (h->dynindx == -1 && !h->forced_local)
+ return TRUE;
+ }
+
/* If we have a MIPS16 function with a stub, the dynamic symbol must
refer to the stub, since only the stub uses the standard calling
conventions. */
@@ -10966,9 +11738,39 @@ _bfd_mips_elf_finish_dynamic_symbol (bfd *output_bfd,
sym->st_other -= STO_MICROMIPS;
}
+ if (hmips->needs_iplt)
+ {
+ /* Point at the iplt stub for this ifunc symbol. */
+ sym->st_value = htab->root.iplt->output_section->vma
+ + htab->root.iplt->output_offset + hmips->iplt_offset;
+ sym->st_info = ELF_ST_INFO (STB_GLOBAL, STT_FUNC);
+ if (ELF_ST_IS_COMPRESSED (hmips->root.other))
+ sym->st_value |= 1;
+ }
+
return TRUE;
}
+/* Finish up local dynamic symbol handling. We set the contents of
+ various dynamic sections here. */
+
+static bfd_boolean
+_bfd_mips_elf_finish_local_dynamic_symbol (void **slot, void *inf)
+{
+ struct mips_elf_link_hash_entry *h = (struct mips_elf_link_hash_entry *) *slot;
+ struct bfd_link_info *info = (struct bfd_link_info *)inf;
+ Elf_Internal_Sym isym;
+
+ isym.st_value = h->root.root.u.def.section->output_section->vma
+ + h->root.root.u.def.section->output_offset + h->root.root.u.def.value;
+ isym.st_other = h->root.other;
+ if (ELF_ST_IS_COMPRESSED (isym.st_other))
+ isym.st_value |= 1;
+
+ return _bfd_mips_elf_finish_dynamic_symbol (info->output_bfd, info,
+ &h->root, &isym);
+}
+
/* Likewise, for VxWorks. */
bfd_boolean
@@ -11354,6 +12156,13 @@ _bfd_mips_elf_finish_dynamic_sections (bfd *output_bfd,
sgot = htab->sgot;
gg = htab->got_info;
+ if (htab_elements (htab->loc_hash_table) > 0)
+ {
+ /* Fill PLT and GOT entries for local STT_GNU_IFUNC symbols. */
+ htab_traverse (htab->loc_hash_table,
+ _bfd_mips_elf_finish_local_dynamic_symbol, info);
+ }
+
if (elf_hash_table (info)->dynamic_sections_created)
{
bfd_byte *b;
@@ -11524,6 +12333,10 @@ _bfd_mips_elf_finish_dynamic_sections (bfd *output_bfd,
dyn.d_un.d_ptr = s->vma;
break;
+ case DT_MIPS_GENERAL_GOTNO:
+ dyn.d_un.d_val = htab->reserved_gotno + gg->general_gotno;
+ break;
+
case DT_RELASZ:
BFD_ASSERT (htab->is_vxworks);
/* The count does not include the JUMP_SLOT relocations. */
@@ -13858,6 +14671,48 @@ _bfd_mips_elf_relax_section (bfd *abfd, asection *sec,
return FALSE;
}
+/* Compute a hash of a local hash entry. We use elf_link_hash_entry
+ for local symbol so that we can handle local STT_GNU_IFUNC symbols
+ as global symbol. We reuse indx and dynstr_index for local symbol
+ hash since they aren't used by global symbols in this backend. */
+
+static hashval_t
+local_htab_hash (const void *ptr)
+{
+ struct mips_elf_link_hash_entry *h =
+ (struct mips_elf_link_hash_entry *) ptr;
+ return ELF_LOCAL_SYMBOL_HASH (h->root.indx, h->root.dynstr_index);
+}
+
+/* Compare local hash entries. */
+
+static int
+local_htab_eq (const void *ptr1, const void *ptr2)
+{
+ struct mips_elf_link_hash_entry *h1 =
+ (struct mips_elf_link_hash_entry *) ptr1;
+ struct mips_elf_link_hash_entry *h2 =
+ (struct mips_elf_link_hash_entry *) ptr2;
+
+ return h1->root.indx == h2->root.indx &&
+ h1->root.dynstr_index == h2->root.dynstr_index;
+}
+
+/* Destroy a MIPS ELF linker hash table. */
+
+static void
+_bfd_mips_elf_link_hash_table_free (bfd *obfd)
+{
+ struct mips_elf_link_hash_table *htab;
+
+ htab = (struct mips_elf_link_hash_table *) obfd->link.hash;
+ if (htab->loc_hash_table)
+ htab_delete (htab->loc_hash_table);
+ if (htab->loc_hash_memory)
+ objalloc_free ((struct objalloc *) htab->loc_hash_memory);
+ _bfd_elf_link_hash_table_free (obfd);
+}
+
/* Create a MIPS ELF linker hash table. */
struct bfd_link_hash_table *
@@ -13881,6 +14736,16 @@ _bfd_mips_elf_link_hash_table_create (bfd *abfd)
ret->root.init_plt_refcount.plist = NULL;
ret->root.init_plt_offset.plist = NULL;
+ /* Create hash table for local IFUNC symbols. */
+ ret->loc_hash_table = htab_try_create (1024, local_htab_hash,
+ local_htab_eq, NULL);
+ ret->loc_hash_memory = objalloc_create ();
+ if (!ret->loc_hash_table || !ret->loc_hash_memory)
+ {
+ _bfd_mips_elf_link_hash_table_free (abfd);
+ return NULL;
+ }
+
return &ret->root.root;
}
@@ -15498,7 +16363,9 @@ _bfd_mips_elf_get_target_dtag (bfd_vma dtag)
return "DT_MIPS_PLTGOT";
case DT_MIPS_RWPLT:
return "DT_MIPS_RWPLT";
- }
+ case DT_MIPS_GENERAL_GOTNO:
+ return "DT_MIPS_GENERAL_GOTNO";
+ }
}
/* Return the meaning of Tag_GNU_MIPS_ABI_FP value FP, or null if
@@ -16130,6 +16997,9 @@ _bfd_mips_post_process_headers (bfd *abfd, struct bfd_link_info *link_info)
if (mips_elf_tdata (abfd)->abiflags.fp_abi == Val_GNU_MIPS_ABI_FP_64
|| mips_elf_tdata (abfd)->abiflags.fp_abi == Val_GNU_MIPS_ABI_FP_64A)
i_ehdrp->e_ident[EI_ABIVERSION] = 3;
+
+ if (elf_tdata (abfd)->has_gnu_symbols & elf_gnu_symbol_ifunc)
+ i_ehdrp->e_ident[EI_ABIVERSION] = 4;
}
int
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index fc70e29..2960a14 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -1199,6 +1199,7 @@ static const char *const bfd_reloc_code_real_names[] = { "@@uninitialized@@",
"BFD_RELOC_MIPS_COPY",
"BFD_RELOC_MIPS_JUMP_SLOT",
+ "BFD_RELOC_MIPS_IRELATIVE",
"BFD_RELOC_MOXIE_10_PCREL",
"BFD_RELOC_FT32_10",
diff --git a/bfd/reloc.c b/bfd/reloc.c
index caa6fb4..d47427e 100644
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -2450,6 +2450,11 @@ ENUMDOC
COMMENT
ENUM
+ BFD_RELOC_MIPS_IRELATIVE
+ENUMDOC
+ MIPS support for STT_GNU_IFUNC.
+
+ENUM
BFD_RELOC_MOXIE_10_PCREL
ENUMDOC
Moxie ELF relocations.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 6298f1e..ce05ac3 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -1718,6 +1718,8 @@ get_mips_dynamic_type (unsigned long type)
case DT_MIPS_AUX_DYNAMIC: return "MIPS_AUX_DYNAMIC";
case DT_MIPS_PLTGOT: return "MIPS_PLTGOT";
case DT_MIPS_RWPLT: return "MIPS_RWPLT";
+ case DT_MIPS_GENERAL_GOTNO: return "MIPS_GENERAL_GOTNO";
+
default:
return NULL;
}
@@ -8508,6 +8510,7 @@ dynamic_section_mips_val (Elf_Internal_Dyn * entry)
case DT_MIPS_DELTA_SYM_NO:
case DT_MIPS_DELTA_CLASSSYM_NO:
case DT_MIPS_COMPACT_SIZE:
+ case DT_MIPS_GENERAL_GOTNO:
print_vma (entry->d_un.d_ptr, DEC);
break;
diff --git a/elfcpp/elfcpp.h b/elfcpp/elfcpp.h
index 722984e..f919fb8 100644
--- a/elfcpp/elfcpp.h
+++ b/elfcpp/elfcpp.h
@@ -866,6 +866,8 @@ enum DT
DT_MIPS_PLTGOT = 0x70000032,
// Points to the base of a writable PLT.
DT_MIPS_RWPLT = 0x70000034,
+ // The GOT index of the first implicitly relocated GOT entry.
+ DT_MIPS_GENERAL_GOTNO = 0x70000036,
DT_AUXILIARY = 0x7ffffffd,
DT_USED = 0x7ffffffe,
diff --git a/include/elf/mips.h b/include/elf/mips.h
index 57de3bc..962d4d0 100644
--- a/include/elf/mips.h
+++ b/include/elf/mips.h
@@ -115,6 +115,9 @@ START_RELOC_NUMBERS (elf_mips_reloc_type)
RELOC_NUMBER (R_MIPS_COPY, 126)
RELOC_NUMBER (R_MIPS_JUMP_SLOT, 127)
+ /* STT_GNU_IFUNC support. */
+ RELOC_NUMBER (R_MIPS_IRELATIVE, 128)
+
/* These relocations are specific to microMIPS. */
FAKE_RELOC (R_MICROMIPS_min, 130)
RELOC_NUMBER (R_MICROMIPS_26_S1, 133)
@@ -751,6 +754,10 @@ extern void bfd_mips_elf32_swap_reginfo_out
/* Relative offset of run time loader map, used for debugging. */
#define DT_MIPS_RLD_MAP_REL 0x70000035
+
+/* The GOT index of the first implicitly relocated GOT entry. */
+#define DT_MIPS_GENERAL_GOTNO 0x70000036
+
/* Flags which may appear in a DT_MIPS_FLAGS entry. */
--
1.7.9.5