From: Yuri Gribov Date: Thu, 27 Feb 2014 14:35:37 +0000 (+0000) Subject: This patch adds support for ARM PLT entries that support a full 32-bit offset range. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1db37fe62781b677a37acbe801c1e69d8912a124;p=binutils-gdb.git This patch adds support for ARM PLT entries that support a full 32-bit offset range. Enabled via the use of a new linker command line option: --long-plt. * bfd-in.h: Add export of bfd_elf32_arm_use_long_plt. * bfd-in2.h: Regenerate. * elf32-arm.c (elf32_arm_plt_entry_long): New array. (elf32_arm_link_hash_table_create): Set plt_entry_size to 16 if using long PLT entries. (bfd_elf32_arm_use_long_plt): New function. (elf32_arm_populate_plt_entry): Add support for long PLT entries. * emultempl/armelf.em (OPTION_LONG_PLT): Define. (PARSE_AND_LIST_LONGOPTS): Add long-plt. (PARSE_AND_LIST_OPTIONS): Likewise. (PARSE_AND_LIST_ARGS_CASES): Handle long-plt. * ld.texinfo: Document --long-plt. * ld-arm/long-plt-format.s: New test case. * ld-arm/long-plt-format.d: Expected disassembly. * ld-arm/arm-elf.exp: Run the new test. --- diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 069a6ce53bf..472bc893914 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,13 @@ +2014-02-27 Yuri Gribov + + * bfd-in.h: Add export of bfd_elf32_arm_use_long_plt. + * bfd-in2.h: Regenerate. + * elf32-arm.c (elf32_arm_plt_entry_long): New array. + (elf32_arm_link_hash_table_create): Set plt_entry_size to 16 if + using long PLT entries. + (bfd_elf32_arm_use_long_plt): New function. + (elf32_arm_populate_plt_entry): Add support for long PLT entries. + 2014-02-27 Alan Modra * elf32-ppc.c (ppc_elf_link_hash_table_create): Provide default diff --git a/bfd/bfd-in.h b/bfd/bfd-in.h index c7c5a7dbddf..54ddac93bd2 100644 --- a/bfd/bfd-in.h +++ b/bfd/bfd-in.h @@ -1,6 +1,6 @@ /* Main header file for the bfd library -- portable access to object files. - Copyright 1990-2013 Free Software Foundation, Inc. + Copyright 1990-2014 Free Software Foundation, Inc. Contributed by Cygnus Support. @@ -877,15 +877,19 @@ extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking extern bfd_boolean bfd_elf32_arm_add_glue_sections_to_bfd (bfd *, struct bfd_link_info *); -/* ELF ARM mapping symbol support */ +/* ELF ARM mapping symbol support. */ #define BFD_ARM_SPECIAL_SYM_TYPE_MAP (1 << 0) #define BFD_ARM_SPECIAL_SYM_TYPE_TAG (1 << 1) #define BFD_ARM_SPECIAL_SYM_TYPE_OTHER (1 << 2) #define BFD_ARM_SPECIAL_SYM_TYPE_ANY (~0) + extern bfd_boolean bfd_is_arm_special_symbol_name - (const char * name, int type); + (const char *, int); + +extern void bfd_elf32_arm_set_byteswap_code + (struct bfd_link_info *, int); -extern void bfd_elf32_arm_set_byteswap_code (struct bfd_link_info *, int); +extern void bfd_elf32_arm_use_long_plt (void); /* ARM Note section processing. */ extern bfd_boolean bfd_arm_merge_machines diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h index 33792f45a5e..ebc74966d1c 100644 --- a/bfd/bfd-in2.h +++ b/bfd/bfd-in2.h @@ -7,7 +7,7 @@ /* Main header file for the bfd library -- portable access to object files. - Copyright 1990-2013 Free Software Foundation, Inc. + Copyright 1990-2014 Free Software Foundation, Inc. Contributed by Cygnus Support. @@ -884,15 +884,19 @@ extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking extern bfd_boolean bfd_elf32_arm_add_glue_sections_to_bfd (bfd *, struct bfd_link_info *); -/* ELF ARM mapping symbol support */ +/* ELF ARM mapping symbol support. */ #define BFD_ARM_SPECIAL_SYM_TYPE_MAP (1 << 0) #define BFD_ARM_SPECIAL_SYM_TYPE_TAG (1 << 1) #define BFD_ARM_SPECIAL_SYM_TYPE_OTHER (1 << 2) #define BFD_ARM_SPECIAL_SYM_TYPE_ANY (~0) + extern bfd_boolean bfd_is_arm_special_symbol_name - (const char * name, int type); + (const char *, int); + +extern void bfd_elf32_arm_set_byteswap_code + (struct bfd_link_info *, int); -extern void bfd_elf32_arm_set_byteswap_code (struct bfd_link_info *, int); +extern void bfd_elf32_arm_use_long_plt (void); /* ARM Note section processing. */ extern bfd_boolean bfd_arm_merge_machines diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c index 72162449c3a..b17f4d435d9 100644 --- a/bfd/elf32-arm.c +++ b/bfd/elf32-arm.c @@ -1,5 +1,5 @@ /* 32-bit ELF support for ARM - Copyright 1998-2013 Free Software Foundation, Inc. + Copyright 1998-2014 Free Software Foundation, Inc. This file is part of BFD, the Binary File Descriptor library. @@ -2140,15 +2140,27 @@ static const bfd_vma elf32_arm_plt0_entry [] = 0x00000000, /* &GOT[0] - . */ }; -/* Subsequent entries in a procedure linkage table look like - this. */ -static const bfd_vma elf32_arm_plt_entry [] = +/* By default subsequent entries in a procedure linkage table look like + this. Offsets that don't fit into 28 bits will cause link error. */ +static const bfd_vma elf32_arm_plt_entry_short [] = { 0xe28fc600, /* add ip, pc, #0xNN00000 */ 0xe28cca00, /* add ip, ip, #0xNN000 */ 0xe5bcf000, /* ldr pc, [ip, #0xNNN]! */ }; +/* When explicitly asked, we'll use this "long" entry format + which can cope with arbitrary displacements. */ +static const bfd_vma elf32_arm_plt_entry_long [] = +{ + 0xe28fc200, /* add ip, pc, #0xN0000000 */ + 0xe28cc600, /* add ip, ip, #0xNN00000 */ + 0xe28cca00, /* add ip, ip, #0xNN000 */ + 0xe5bcf000, /* ldr pc, [ip, #0xNNN]! */ +}; + +static bfd_boolean elf32_arm_use_long_plt_entry = FALSE; + #endif /* The format of the first entry in the procedure linkage table @@ -3464,7 +3476,7 @@ elf32_arm_link_hash_table_create (bfd *abfd) ret->plt_entry_size = 16; #else ret->plt_header_size = 20; - ret->plt_entry_size = 12; + ret->plt_entry_size = elf32_arm_use_long_plt_entry ? 16 : 12; #endif ret->use_rel = 1; ret->obfd = abfd; @@ -6027,6 +6039,15 @@ arm_make_glue_section (bfd * abfd, const char * name) return TRUE; } +/* Set size of .plt entries. This function is called from the + linker scripts in ld/emultempl/{armelf}.em. */ + +void +bfd_elf32_arm_use_long_plt (void) +{ + elf32_arm_use_long_plt_entry = TRUE; +} + /* Add the glue sections to ABFD. This function is called from the linker scripts in ld/emultempl/{armelf}.em. */ @@ -7705,8 +7726,6 @@ elf32_arm_populate_plt_entry (bfd *output_bfd, struct bfd_link_info *info, of the PLT stub. */ got_displacement = got_address - (plt_address + 8); - BFD_ASSERT ((got_displacement & 0xf0000000) == 0); - if (elf32_arm_plt_needs_thumb_stub_p (info, arm_plt)) { put_thumb_insn (htab, output_bfd, @@ -7715,21 +7734,45 @@ elf32_arm_populate_plt_entry (bfd *output_bfd, struct bfd_link_info *info, elf32_arm_plt_thumb_stub[1], ptr - 2); } - put_arm_insn (htab, output_bfd, - elf32_arm_plt_entry[0] - | ((got_displacement & 0x0ff00000) >> 20), - ptr + 0); - put_arm_insn (htab, output_bfd, - elf32_arm_plt_entry[1] - | ((got_displacement & 0x000ff000) >> 12), - ptr+ 4); - put_arm_insn (htab, output_bfd, - elf32_arm_plt_entry[2] - | (got_displacement & 0x00000fff), - ptr + 8); + if (!elf32_arm_use_long_plt_entry) + { + BFD_ASSERT ((got_displacement & 0xf0000000) == 0); + + put_arm_insn (htab, output_bfd, + elf32_arm_plt_entry_short[0] + | ((got_displacement & 0x0ff00000) >> 20), + ptr + 0); + put_arm_insn (htab, output_bfd, + elf32_arm_plt_entry_short[1] + | ((got_displacement & 0x000ff000) >> 12), + ptr+ 4); + put_arm_insn (htab, output_bfd, + elf32_arm_plt_entry_short[2] + | (got_displacement & 0x00000fff), + ptr + 8); #ifdef FOUR_WORD_PLT - bfd_put_32 (output_bfd, elf32_arm_plt_entry[3], ptr + 12); + bfd_put_32 (output_bfd, elf32_arm_plt_entry_short[3], ptr + 12); #endif + } + else + { + put_arm_insn (htab, output_bfd, + elf32_arm_plt_entry_long[0] + | ((got_displacement & 0xf0000000) >> 28), + ptr + 0); + put_arm_insn (htab, output_bfd, + elf32_arm_plt_entry_long[1] + | ((got_displacement & 0x0ff00000) >> 20), + ptr + 4); + put_arm_insn (htab, output_bfd, + elf32_arm_plt_entry_long[2] + | ((got_displacement & 0x000ff000) >> 12), + ptr+ 8); + put_arm_insn (htab, output_bfd, + elf32_arm_plt_entry_long[3] + | (got_displacement & 0x00000fff), + ptr + 12); + } } /* Fill in the entry in the .rel(a).(i)plt section. */ diff --git a/ld/ChangeLog b/ld/ChangeLog index a0c52842e94..57120d15fb9 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,11 @@ +2014-02-27 Yuri Gribov + + * emultempl/armelf.em (OPTION_LONG_PLT): Define. + (PARSE_AND_LIST_LONGOPTS): Add long-plt. + (PARSE_AND_LIST_OPTIONS): Likewise. + (PARSE_AND_LIST_ARGS_CASES): Handle long-plt. + * ld.texinfo: Document --long-plt. + 2014-02-27 Alan Modra * emulparams/elf32ppcvxworks.sh: Source plt_unwind.sh and diff --git a/ld/emultempl/armelf.em b/ld/emultempl/armelf.em index 85e924fcb24..6a64793f68c 100644 --- a/ld/emultempl/armelf.em +++ b/ld/emultempl/armelf.em @@ -1,5 +1,5 @@ # This shell script emits a C file. -*- C -*- -# Copyright 1991-2013 Free Software Foundation, Inc. +# Copyright 1991-2014 Free Software Foundation, Inc. # # This file is part of the GNU Binutils. # @@ -28,10 +28,10 @@ fragment < + + * ld-arm/long-plt-format.s: New test case. + * ld-arm/long-plt-format.d: Expected disassembly. + * ld-arm/arm-elf.exp: Run the new test. + 2014-02-27 Nick Clifton * ld-pe/longsecn-1.d: Allow for extra sections. diff --git a/ld/testsuite/ld-arm/arm-elf.exp b/ld/testsuite/ld-arm/arm-elf.exp index 4c0f8026244..ec569ca0dbd 100644 --- a/ld/testsuite/ld-arm/arm-elf.exp +++ b/ld/testsuite/ld-arm/arm-elf.exp @@ -1,5 +1,5 @@ # Expect script for various ARM ELF tests. -# Copyright 2002-2013 Free Software Foundation, Inc. +# Copyright 2002-2014 Free Software Foundation, Inc. # # This file is part of the GNU Binutils. # @@ -188,6 +188,10 @@ set armelftests_common { "" {exec-got-1b.s} {{readelf --relocs exec-got-1.d}} "exec-got-1"} + {"Long PLT entries in executables" "--long-plt -shared --section-start=.plt=0x200 --section-start=.got=0xf0000300" "" + "" {long-plt-format.s} + {{objdump "-d -j .plt" long-plt-format.d}} + "long-plt-format"} {"abs call" "-T arm.ld" "" "" {abs-call-1.s} {{objdump -d abs-call-1.d}} "abs-call-1"} diff --git a/ld/testsuite/ld-arm/long-plt-format.d b/ld/testsuite/ld-arm/long-plt-format.d new file mode 100644 index 00000000000..c08cb71f325 --- /dev/null +++ b/ld/testsuite/ld-arm/long-plt-format.d @@ -0,0 +1,15 @@ +.*: file format elf32-.* + + +Disassembly of section .plt: + +00000200 <.plt>: + 200: .* + 204: .* + 208: .* + 20c: .* + 210: .* .word .* + 214: .* add ip, pc, #-268435456 ; 0xf0000000 + 218: .* add ip, ip, #0, 12 + 21c: .* add ip, ip, #0, 20 + 220: .* ldr pc, [ip, #[0-9]*]! ; 0x.* diff --git a/ld/testsuite/ld-arm/long-plt-format.s b/ld/testsuite/ld-arm/long-plt-format.s new file mode 100644 index 00000000000..bb0c3a22958 --- /dev/null +++ b/ld/testsuite/ld-arm/long-plt-format.s @@ -0,0 +1,7 @@ + .globl _start + .type _start,%function + .globl foo +_start: + bl foo(PLT) + .size _start,.-_start +