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[binutils-gdb] [ARM] Purecode compatible long branch veneer for M-profile targets with MOVW.
- From: Richard Earnshaw <rearnsha at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 5 Jul 2016 10:41:19 -0000
- Subject: [binutils-gdb] [ARM] Purecode compatible long branch veneer for M-profile targets with MOVW.
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d5a67c02901c0abe946546f2b3b1a3b67a876136
commit d5a67c02901c0abe946546f2b3b1a3b67a876136
Author: Andre Vieria <andre.simoesdiasvieira@arm.com>
Date: Tue Jul 5 11:39:06 2016 +0100
[ARM] Purecode compatible long branch veneer for M-profile targets with MOVW.
2016-07-05 Andre Vieria <andre.simoesdiasvieira@arm.com>
* 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 <andre.simoesdiasvieira@arm.com>
* 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.
Diff:
---
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(-)
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 <andre.simoesdiasvieira@arm.com>
+ * 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 <andre.simoesdiasvieira@arm.com>
+
* 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 <andre.simoesdiasvieira@arm.com>
+ * 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 <andre.simoesdiasvieira@arm.com>
+
* 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 <bar>:
+ 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