From d5a67c02901c0abe946546f2b3b1a3b67a876136 Mon Sep 17 00:00:00 2001 From: Andre Vieria Date: Tue, 5 Jul 2016 11:39:06 +0100 Subject: [PATCH] [ARM] Purecode compatible long branch veneer for M-profile targets with MOVW. 2016-07-05 Andre Vieria * elf32-arm.c (THUMB32_MOVT): New veneer macro. (THUMB32_MOVW): Likewise. (elf32_arm_stub_long_branch_thumb2_only_pure): New. (DEF_STUBS): Define long_branch_thumb2_only_pure. (arm_stub_is_thumb): Add new veneer stub. (arm_type_of_stub): Use new veneer. (arm_stub_required_alignment): Add new veneer. 2016-07-05 Andre Vieria * testsuite/ld-arm/farcall-thumb2-purecode.d: New test result. * testsuite/ld-arm/farcall-thumb2-purecode.s: New test. * testsuite/ld-arm/arm-elf.exp: Run it. --- bfd/ChangeLog | 10 ++++ bfd/elf32-arm.c | 73 ++++++++++++++++++++++++--- ld/ChangeLog | 6 +++ ld/testsuite/ld-arm/arm-elf.exp | 3 ++ ld/testsuite/ld-arm/farcall-thumb2-purecode.d | 22 ++++++++ ld/testsuite/ld-arm/farcall-thumb2-purecode.s | 19 +++++++ 6 files changed, 127 insertions(+), 6 deletions(-) create mode 100644 ld/testsuite/ld-arm/farcall-thumb2-purecode.d create mode 100644 ld/testsuite/ld-arm/farcall-thumb2-purecode.s diff --git a/bfd/ChangeLog b/bfd/ChangeLog index cff9b32..4031171 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,5 +1,15 @@ 2016-07-05 Andre Vieria + * elf32-arm.c (THUMB32_MOVT): New veneer macro. + (THUMB32_MOVW): Likewise. + (elf32_arm_stub_long_branch_thumb2_only_pure): New. + (DEF_STUBS): Define long_branch_thumb2_only_pure. + (arm_stub_is_thumb): Add new veneer stub. + (arm_type_of_stub): Use new veneer. + (arm_stub_required_alignment): Add new veneer. + +2016-07-05 Andre Vieria + * bfd-in2.h (SEC_ELF_NOREAD): Rename to ... (SEC_ELF_PURECODE): ... this. * elf32-arm.c (elf32_arm_post_process_headers): Rename SEC_ELF_NOREAD diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c index 9331471..834d615 100644 --- a/bfd/elf32-arm.c +++ b/bfd/elf32-arm.c @@ -2360,6 +2360,8 @@ enum stub_insn_type is inserted in arm_build_one_stub(). */ #define THUMB16_BCOND_INSN(X) {(X), THUMB16_TYPE, R_ARM_NONE, 1} #define THUMB32_INSN(X) {(X), THUMB32_TYPE, R_ARM_NONE, 0} +#define THUMB32_MOVT(X) {(X), THUMB32_TYPE, R_ARM_THM_MOVT_ABS, 0} +#define THUMB32_MOVW(X) {(X), THUMB32_TYPE, R_ARM_THM_MOVW_ABS_NC, 0} #define THUMB32_B_INSN(X, Z) {(X), THUMB32_TYPE, R_ARM_THM_JUMP24, (Z)} #define ARM_INSN(X) {(X), ARM_TYPE, R_ARM_NONE, 0} #define ARM_REL_INSN(X, Z) {(X), ARM_TYPE, R_ARM_JUMP24, (Z)} @@ -2409,6 +2411,15 @@ static const insn_sequence elf32_arm_stub_long_branch_thumb2_only[] = DATA_WORD (0, R_ARM_ABS32, 0), /* dcd R_ARM_ABS32(x) */ }; +/* Thumb -> Thumb long branch stub. Used for PureCode sections on Thumb2 + M-profile architectures. */ +static const insn_sequence elf32_arm_stub_long_branch_thumb2_only_pure[] = +{ + THUMB32_MOVW (0xf2400c00), /* mov.w ip, R_ARM_MOVW_ABS_NC */ + THUMB32_MOVT (0xf2c00c00), /* movt ip, R_ARM_MOVT_ABS << 16 */ + THUMB16_INSN (0x4760), /* bx ip */ +}; + /* V4T Thumb -> Thumb long branch stub. Using the stack is not allowed. */ static const insn_sequence elf32_arm_stub_long_branch_v4t_thumb_thumb[] = @@ -2634,6 +2645,7 @@ static const insn_sequence elf32_arm_stub_a8_veneer_blx[] = DEF_STUB(a8_veneer_bl) \ DEF_STUB(a8_veneer_blx) \ DEF_STUB(long_branch_thumb2_only) \ + DEF_STUB(long_branch_thumb2_only_pure) #define DEF_STUB(x) arm_stub_##x, enum elf32_arm_stub_type @@ -3808,6 +3820,7 @@ arm_stub_is_thumb (enum elf32_arm_stub_type stub_type) { case arm_stub_long_branch_thumb_only: case arm_stub_long_branch_thumb2_only: + case arm_stub_long_branch_thumb2_only_pure: case arm_stub_long_branch_v4t_thumb_arm: case arm_stub_short_branch_v4t_thumb_arm: case arm_stub_long_branch_v4t_thumb_arm_pic: @@ -3847,6 +3860,8 @@ arm_type_of_stub (struct bfd_link_info *info, enum arm_st_branch_type branch_type = *actual_branch_type; union gotplt_union *root_plt; struct arm_plt_info *arm_plt; + int arch; + int thumb2_movw; if (branch_type == ST_BRANCH_LONG) return stub_type; @@ -3859,6 +3874,11 @@ arm_type_of_stub (struct bfd_link_info *info, thumb2 = using_thumb2 (globals); thumb2_bl = using_thumb2_bl (globals); + arch = bfd_elf_get_obj_attr_int (globals->obfd, OBJ_ATTR_PROC, Tag_CPU_arch); + + /* True for architectures that implement the thumb2 movw instruction. */ + thumb2_movw = thumb2 || (arch == TAG_CPU_ARCH_V8M_BASE); + /* Determine where the call point is. */ location = (input_sec->output_offset + input_sec->output_section->vma @@ -3945,6 +3965,15 @@ arm_type_of_stub (struct bfd_link_info *info, /* Thumb to thumb. */ if (!thumb_only) { + if (input_sec->flags & SEC_ELF_PURECODE) + (*_bfd_error_handler) (_("%B(%s): warning: long branch " + " veneers used in section with " + "SHF_ARM_PURECODE section " + "attribute is only supported" + " for M-profile targets that " + "implement the movw " + "instruction.")); + stub_type = (bfd_link_pic (info) | globals->pic_veneer) /* PIC stubs. */ ? ((globals->use_blx @@ -3967,16 +3996,39 @@ arm_type_of_stub (struct bfd_link_info *info, } else { - stub_type = (bfd_link_pic (info) | globals->pic_veneer) - /* PIC stub. */ - ? arm_stub_long_branch_thumb_only_pic - /* non-PIC stub. */ - : (thumb2 ? arm_stub_long_branch_thumb2_only - : arm_stub_long_branch_thumb_only); + if (thumb2_movw && (input_sec->flags & SEC_ELF_PURECODE)) + stub_type = arm_stub_long_branch_thumb2_only_pure; + else + { + if (input_sec->flags & SEC_ELF_PURECODE) + (*_bfd_error_handler) (_("%B(%s): warning: long branch " + " veneers used in section with " + "SHF_ARM_PURECODE section " + "attribute is only supported" + " for M-profile targets that " + "implement the movw " + "instruction.")); + + stub_type = (bfd_link_pic (info) | globals->pic_veneer) + /* PIC stub. */ + ? arm_stub_long_branch_thumb_only_pic + /* non-PIC stub. */ + : (thumb2 ? arm_stub_long_branch_thumb2_only + : arm_stub_long_branch_thumb_only); + } } } else { + if (input_sec->flags & SEC_ELF_PURECODE) + (*_bfd_error_handler) (_("%B(%s): warning: long branch " + " veneers used in section with " + "SHF_ARM_PURECODE section " + "attribute is only supported" + " for M-profile targets that " + "implement the movw " + "instruction.")); + /* Thumb to arm. */ if (sym_sec != NULL && sym_sec->owner != NULL @@ -4021,6 +4073,14 @@ arm_type_of_stub (struct bfd_link_info *info, || r_type == R_ARM_PLT32 || r_type == R_ARM_TLS_CALL) { + if (input_sec->flags & SEC_ELF_PURECODE) + (*_bfd_error_handler) (_("%B(%s): warning: long branch " + " veneers used in section with " + "SHF_ARM_PURECODE section " + "attribute is only supported" + " for M-profile targets that " + "implement the movw " + "instruction.")); if (branch_type == ST_BRANCH_TO_THUMB) { /* Arm to thumb. */ @@ -4446,6 +4506,7 @@ arm_stub_required_alignment (enum elf32_arm_stub_type stub_type) case arm_stub_long_branch_v4t_arm_thumb: case arm_stub_long_branch_thumb_only: case arm_stub_long_branch_thumb2_only: + case arm_stub_long_branch_thumb2_only_pure: case arm_stub_long_branch_v4t_thumb_thumb: case arm_stub_long_branch_v4t_thumb_arm: case arm_stub_short_branch_v4t_thumb_arm: diff --git a/ld/ChangeLog b/ld/ChangeLog index cc598af..6ee54fc 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,5 +1,11 @@ 2016-07-05 Andre Vieria + * testsuite/ld-arm/farcall-thumb2-purecode.d: New test result. + * testsuite/ld-arm/farcall-thumb2-purecode.s: New test. + * testsuite/ld-arm/arm-elf.exp: Run it. + +2016-07-05 Andre Vieria + * testsuite/ld-arm/arm_noread.ld: Renamed to ... testsuite/ld-arm/arm_purecode.ld: ... this, and replaced all noread's by purecode. diff --git a/ld/testsuite/ld-arm/arm-elf.exp b/ld/testsuite/ld-arm/arm-elf.exp index 597bdcf..d0c9a2f 100644 --- a/ld/testsuite/ld-arm/arm-elf.exp +++ b/ld/testsuite/ld-arm/arm-elf.exp @@ -505,6 +505,9 @@ set armeabitests_nonacl { {farcall-thumb-thumb-m-no-profile-a.s farcall-thumb-thumb-m-no-profile-b.s} {{objdump -d farcall-thumb-thumb-m-no-profile.d}} "farcall-thumb-thumb-m-no-profile"} + {"Thumb2 purecode farcall" "-Ttext 0x1000 --section-start .foo=0x2001020" "" "" {farcall-thumb2-purecode.s} + {{objdump -d farcall-thumb2-purecode.d}} + "farcall-thumb2-purecode"} {"Thumb-ARM farcall" "-Ttext 0x1c01010 --section-start .foo=0x2001014" "" "-W" {farcall-thumb-arm.s} {{objdump -d farcall-thumb-arm.d}} diff --git a/ld/testsuite/ld-arm/farcall-thumb2-purecode.d b/ld/testsuite/ld-arm/farcall-thumb2-purecode.d new file mode 100644 index 0000000..2a62fe4 --- /dev/null +++ b/ld/testsuite/ld-arm/farcall-thumb2-purecode.d @@ -0,0 +1,22 @@ +.*: file format .* + +Disassembly of section .text: + +00001000 : + 1000: 4770 bx lr + +Disassembly of section .foo: + +02001020 <_start>: + 2001020: f000 f802 bl 2001028 <__bar_veneer> + 2001024: 0000 movs r0, r0 + \.\.\. + +02001028 <__bar_veneer>: + 2001028: f241 0c01 movw ip, #4097 ; 0x1001 + 200102c: f2c0 0c00 movt ip, #0 + 2001030: 4760 bx ip + 2001032: 0000 movs r0, r0 + 2001034: 0000 movs r0, r0 + \.\.\. + diff --git a/ld/testsuite/ld-arm/farcall-thumb2-purecode.s b/ld/testsuite/ld-arm/farcall-thumb2-purecode.s new file mode 100644 index 0000000..a16731a --- /dev/null +++ b/ld/testsuite/ld-arm/farcall-thumb2-purecode.s @@ -0,0 +1,19 @@ +@ Test to ensure that a purecode Thumb2 call exceeding 4Mb generates a stub. + + .global _start + .syntax unified + .arch armv7-m + .thumb + .thumb_func + +@ We will place the section .text at 0x1000. + + .text +bar: + bx lr + +@ We will place the section .foo at 0x02001014. + + .section .foo, "0x20000006" +_start: + bl bar -- 2.7.4