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binutils-gdb/include/elf/ppc64.h
Alan Modra 23cedd1dc9 PowerPC inline PLT call support 
In addition to the existing relocs we need two more to mark all
instructions in the call sequence, PLTCALL on the call itself (plus
the toc restore insn for ppc64), and PLTSEQ on others.  All
relocations in a particular sequence have the same symbol.

Example ppc64 ELFv2 assembly:
 .reloc .,R_PPC64_PLTSEQ,puts
	std 2,24(1)
	addis 12,2,puts@plt@ha	# .reloc .,R_PPC64_PLT16_HA,puts
	ld 12,puts@plt@l(12)	# .reloc .,R_PPC64_PLT16_LO_DS,puts
 .reloc .,R_PPC64_PLTSEQ,puts
	mtctr 12
 .reloc .,R_PPC64_PLTCALL,puts
	bctrl
	ld 2,24(1)

Example ppc32 -fPIC assembly:
	addis 12,30,puts+32768@plt@ha # .reloc .,R_PPC_PLT16_HA,puts+0x8000
	lwz 12,12,puts+32768@plt@l    # .reloc .,R_PPC_PLT16_LO,puts+0x8000
 .reloc .,R_PPC_PLTSEQ,puts+32768
	mtctr 12
 .reloc .,R_PPC_PLTCALL,puts+32768
	bctrl

Marking sequences like this allows the linker to convert them to nops
and a direct call if the target symbol turns out to be local.

When the call is __tls_get_addr, each relocation shown above is paired
with an R_PPC*_TLSLD or R_PPC*_TLSGD reloc to additionally mark the
sequence for possible TLS optimization.  The TLSLD or TLSGD relocs are
emitted first.

include/
	* elf/ppc.h (R_PPC_PLTSEQ, R_PPC_PLTCALL): Define.
	* elf/ppc64.h (R_PPC64_PLTSEQ, R_PPC64_PLTCALL): Define.
bfd/
	* elf32-ppc.c (ppc_elf_howto_raw): Add PLTSEQ and PLTCALL howtos.
	(is_plt_seq_reloc): New function.
	(ppc_elf_check_relocs): Handle PLTSEQ and PLTCALL relocs.
	(ppc_elf_tls_optimize): Handle inline plt call sequence.
	(ppc_elf_relax_section): Handle PLTCALL reloc.
	(ppc_elf_relocate_section): Nop out inline plt call sequence when
	resolving locally.
	* elf64-ppc.c (ppc64_elf_howto_raw): Add R_PPC64_PLTSEQ and
	R_PPC64_PLTCALL entries.  Comment R_PPC64_TOCSAVE.
	(has_tls_get_addr_call): Correct comment.
	(is_branch_reloc): Add PLTCALL.
	(is_plt_seq_reloc): New function.
	(ppc64_elf_check_relocs): Handle PLT16_LO_DS reloc.  Set
	has_tls_reloc for R_PPC64_TLSGD and R_PPC64_TLSLD.  Create plt
	entry for R_PPC64_PLTCALL.
	(ppc64_elf_tls_optimize): Handle inline plt call sequence.
	(ppc_type_of_stub): Handle PLTCALL reloc.
	(toc_adjusting_stub_needed): Likewise.
	(ppc64_elf_relocate_section): Set "can_plt_call" for PLTCALL
	reloc insn.  Nop out inline plt call sequence when resolving
	locally.  Handle __tls_get_addr inline plt call optimization.
elfcpp/
	* powerpc.h (R_POWERPC_PLTSEQ, R_POWERPC_PLTCALL): Define.
gold/
	* powerpc.cc (Target_powerpc::Track_tls::maybe_skip_tls_get_addr_call):
	Handle inline plt sequence relocs.
	(Stub_table::Plt_stub_key::Plt_stub_key): Likewise.
	(Target_powerpc::Scan::reloc_needs_plt_for_ifunc): Likewise.
	(Target_powerpc::Relocate::relocate): Likewise.
2018-04-09 17:25:20 +09:30

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/* PPC64 ELF support for BFD.
Copyright (C) 2003-2018 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#ifndef _ELF_PPC64_H
#define _ELF_PPC64_H
#include "elf/reloc-macros.h"
/* Relocations. */
START_RELOC_NUMBERS (elf_ppc64_reloc_type)
RELOC_NUMBER (R_PPC64_NONE, 0)
RELOC_NUMBER (R_PPC64_ADDR32, 1)
RELOC_NUMBER (R_PPC64_ADDR24, 2)
RELOC_NUMBER (R_PPC64_ADDR16, 3)
RELOC_NUMBER (R_PPC64_ADDR16_LO, 4)
RELOC_NUMBER (R_PPC64_ADDR16_HI, 5)
RELOC_NUMBER (R_PPC64_ADDR16_HA, 6)
RELOC_NUMBER (R_PPC64_ADDR14, 7)
RELOC_NUMBER (R_PPC64_ADDR14_BRTAKEN, 8)
RELOC_NUMBER (R_PPC64_ADDR14_BRNTAKEN, 9)
RELOC_NUMBER (R_PPC64_REL24, 10)
RELOC_NUMBER (R_PPC64_REL14, 11)
RELOC_NUMBER (R_PPC64_REL14_BRTAKEN, 12)
RELOC_NUMBER (R_PPC64_REL14_BRNTAKEN, 13)
RELOC_NUMBER (R_PPC64_GOT16, 14)
RELOC_NUMBER (R_PPC64_GOT16_LO, 15)
RELOC_NUMBER (R_PPC64_GOT16_HI, 16)
RELOC_NUMBER (R_PPC64_GOT16_HA, 17)
/* 18 unused. 32-bit reloc is R_PPC_PLTREL24. */
RELOC_NUMBER (R_PPC64_COPY, 19)
RELOC_NUMBER (R_PPC64_GLOB_DAT, 20)
RELOC_NUMBER (R_PPC64_JMP_SLOT, 21)
RELOC_NUMBER (R_PPC64_RELATIVE, 22)
/* 23 unused. 32-bit reloc is R_PPC_LOCAL24PC. */
RELOC_NUMBER (R_PPC64_UADDR32, 24)
RELOC_NUMBER (R_PPC64_UADDR16, 25)
RELOC_NUMBER (R_PPC64_REL32, 26)
RELOC_NUMBER (R_PPC64_PLT32, 27)
RELOC_NUMBER (R_PPC64_PLTREL32, 28)
RELOC_NUMBER (R_PPC64_PLT16_LO, 29)
RELOC_NUMBER (R_PPC64_PLT16_HI, 30)
RELOC_NUMBER (R_PPC64_PLT16_HA, 31)
/* 32 unused. 32-bit reloc is R_PPC_SDAREL16. */
RELOC_NUMBER (R_PPC64_SECTOFF, 33)
RELOC_NUMBER (R_PPC64_SECTOFF_LO, 34)
RELOC_NUMBER (R_PPC64_SECTOFF_HI, 35)
RELOC_NUMBER (R_PPC64_SECTOFF_HA, 36)
RELOC_NUMBER (R_PPC64_REL30, 37)
RELOC_NUMBER (R_PPC64_ADDR64, 38)
RELOC_NUMBER (R_PPC64_ADDR16_HIGHER, 39)
RELOC_NUMBER (R_PPC64_ADDR16_HIGHERA, 40)
RELOC_NUMBER (R_PPC64_ADDR16_HIGHEST, 41)
RELOC_NUMBER (R_PPC64_ADDR16_HIGHESTA, 42)
RELOC_NUMBER (R_PPC64_UADDR64, 43)
RELOC_NUMBER (R_PPC64_REL64, 44)
RELOC_NUMBER (R_PPC64_PLT64, 45)
RELOC_NUMBER (R_PPC64_PLTREL64, 46)
RELOC_NUMBER (R_PPC64_TOC16, 47)
RELOC_NUMBER (R_PPC64_TOC16_LO, 48)
RELOC_NUMBER (R_PPC64_TOC16_HI, 49)
RELOC_NUMBER (R_PPC64_TOC16_HA, 50)
RELOC_NUMBER (R_PPC64_TOC, 51)
RELOC_NUMBER (R_PPC64_PLTGOT16, 52)
RELOC_NUMBER (R_PPC64_PLTGOT16_LO, 53)
RELOC_NUMBER (R_PPC64_PLTGOT16_HI, 54)
RELOC_NUMBER (R_PPC64_PLTGOT16_HA, 55)
/* The following relocs were added in the 64-bit PowerPC ELF ABI
revision 1.2. */
RELOC_NUMBER (R_PPC64_ADDR16_DS, 56)
RELOC_NUMBER (R_PPC64_ADDR16_LO_DS, 57)
RELOC_NUMBER (R_PPC64_GOT16_DS, 58)
RELOC_NUMBER (R_PPC64_GOT16_LO_DS, 59)
RELOC_NUMBER (R_PPC64_PLT16_LO_DS, 60)
RELOC_NUMBER (R_PPC64_SECTOFF_DS, 61)
RELOC_NUMBER (R_PPC64_SECTOFF_LO_DS, 62)
RELOC_NUMBER (R_PPC64_TOC16_DS, 63)
RELOC_NUMBER (R_PPC64_TOC16_LO_DS, 64)
RELOC_NUMBER (R_PPC64_PLTGOT16_DS, 65)
RELOC_NUMBER (R_PPC64_PLTGOT16_LO_DS, 66)
/* Relocs added to support TLS. PowerPC64 ELF ABI revision 1.5. */
RELOC_NUMBER (R_PPC64_TLS, 67)
RELOC_NUMBER (R_PPC64_DTPMOD64, 68)
RELOC_NUMBER (R_PPC64_TPREL16, 69)
RELOC_NUMBER (R_PPC64_TPREL16_LO, 70)
RELOC_NUMBER (R_PPC64_TPREL16_HI, 71)
RELOC_NUMBER (R_PPC64_TPREL16_HA, 72)
RELOC_NUMBER (R_PPC64_TPREL64, 73)
RELOC_NUMBER (R_PPC64_DTPREL16, 74)
RELOC_NUMBER (R_PPC64_DTPREL16_LO, 75)
RELOC_NUMBER (R_PPC64_DTPREL16_HI, 76)
RELOC_NUMBER (R_PPC64_DTPREL16_HA, 77)
RELOC_NUMBER (R_PPC64_DTPREL64, 78)
RELOC_NUMBER (R_PPC64_GOT_TLSGD16, 79)
RELOC_NUMBER (R_PPC64_GOT_TLSGD16_LO, 80)
RELOC_NUMBER (R_PPC64_GOT_TLSGD16_HI, 81)
RELOC_NUMBER (R_PPC64_GOT_TLSGD16_HA, 82)
RELOC_NUMBER (R_PPC64_GOT_TLSLD16, 83)
RELOC_NUMBER (R_PPC64_GOT_TLSLD16_LO, 84)
RELOC_NUMBER (R_PPC64_GOT_TLSLD16_HI, 85)
RELOC_NUMBER (R_PPC64_GOT_TLSLD16_HA, 86)
RELOC_NUMBER (R_PPC64_GOT_TPREL16_DS, 87)
RELOC_NUMBER (R_PPC64_GOT_TPREL16_LO_DS, 88)
RELOC_NUMBER (R_PPC64_GOT_TPREL16_HI, 89)
RELOC_NUMBER (R_PPC64_GOT_TPREL16_HA, 90)
RELOC_NUMBER (R_PPC64_GOT_DTPREL16_DS, 91)
RELOC_NUMBER (R_PPC64_GOT_DTPREL16_LO_DS, 92)
RELOC_NUMBER (R_PPC64_GOT_DTPREL16_HI, 93)
RELOC_NUMBER (R_PPC64_GOT_DTPREL16_HA, 94)
RELOC_NUMBER (R_PPC64_TPREL16_DS, 95)
RELOC_NUMBER (R_PPC64_TPREL16_LO_DS, 96)
RELOC_NUMBER (R_PPC64_TPREL16_HIGHER, 97)
RELOC_NUMBER (R_PPC64_TPREL16_HIGHERA, 98)
RELOC_NUMBER (R_PPC64_TPREL16_HIGHEST, 99)
RELOC_NUMBER (R_PPC64_TPREL16_HIGHESTA, 100)
RELOC_NUMBER (R_PPC64_DTPREL16_DS, 101)
RELOC_NUMBER (R_PPC64_DTPREL16_LO_DS, 102)
RELOC_NUMBER (R_PPC64_DTPREL16_HIGHER, 103)
RELOC_NUMBER (R_PPC64_DTPREL16_HIGHERA, 104)
RELOC_NUMBER (R_PPC64_DTPREL16_HIGHEST, 105)
RELOC_NUMBER (R_PPC64_DTPREL16_HIGHESTA, 106)
RELOC_NUMBER (R_PPC64_TLSGD, 107)
RELOC_NUMBER (R_PPC64_TLSLD, 108)
RELOC_NUMBER (R_PPC64_TOCSAVE, 109)
/* Added when HA and HI relocs were changed to report overflows. */
RELOC_NUMBER (R_PPC64_ADDR16_HIGH, 110)
RELOC_NUMBER (R_PPC64_ADDR16_HIGHA, 111)
RELOC_NUMBER (R_PPC64_TPREL16_HIGH, 112)
RELOC_NUMBER (R_PPC64_TPREL16_HIGHA, 113)
RELOC_NUMBER (R_PPC64_DTPREL16_HIGH, 114)
RELOC_NUMBER (R_PPC64_DTPREL16_HIGHA, 115)
/* Added for ELFv2. */
RELOC_NUMBER (R_PPC64_REL24_NOTOC, 116)
RELOC_NUMBER (R_PPC64_ADDR64_LOCAL, 117)
RELOC_NUMBER (R_PPC64_ENTRY, 118)
/* Marker reloc for inline plt call insns. */
RELOC_NUMBER (R_PPC64_PLTSEQ, 119)
RELOC_NUMBER (R_PPC64_PLTCALL, 120)
#ifndef RELOC_MACROS_GEN_FUNC
/* Relocation only used internally by ld. If you need to use these
reloc numbers, you can change them to some other unused value
without affecting the ABI. They will never appear in object files. */
RELOC_NUMBER (R_PPC64_LO_DS_OPT, 128)
/* Reloc only used internally by gas. As above, value is unimportant. */
RELOC_NUMBER (R_PPC64_16DX_HA, 129)
#endif
/* Power9 split rel16 for addpcis. */
RELOC_NUMBER (R_PPC64_REL16DX_HA, 246)
/* Support STT_GNU_IFUNC plt calls. */
RELOC_NUMBER (R_PPC64_JMP_IREL, 247)
RELOC_NUMBER (R_PPC64_IRELATIVE, 248)
/* These are GNU extensions used in PIC code sequences. */
RELOC_NUMBER (R_PPC64_REL16, 249)
RELOC_NUMBER (R_PPC64_REL16_LO, 250)
RELOC_NUMBER (R_PPC64_REL16_HI, 251)
RELOC_NUMBER (R_PPC64_REL16_HA, 252)
/* These are GNU extensions to enable C++ vtable garbage collection. */
RELOC_NUMBER (R_PPC64_GNU_VTINHERIT, 253)
RELOC_NUMBER (R_PPC64_GNU_VTENTRY, 254)
END_RELOC_NUMBERS (R_PPC64_max)
#define IS_PPC64_TLS_RELOC(R) \
(((R) >= R_PPC64_TLS && (R) <= R_PPC64_DTPREL16_HIGHESTA) \
|| ((R) >= R_PPC64_TPREL16_HIGH && (R) <= R_PPC64_DTPREL16_HIGHA))
/* e_flags bits specifying ABI.
1 for original function descriptor using ABI,
2 for revised ABI without function descriptors,
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
/* Specify the start and size of the .opd section. */
#define DT_PPC64_OPD (DT_LOPROC + 1)
#define DT_PPC64_OPDSZ (DT_LOPROC + 2)
/* Specify whether various optimisations are possible. */
#define DT_PPC64_OPT (DT_LOPROC + 3)
#define PPC64_OPT_TLS 1
#define PPC64_OPT_MULTI_TOC 2
#define PPC64_OPT_LOCALENTRY 4
#endif /* _ELF_PPC64_H */
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