[binutils-gdb] Refactor Cortex-A8 erratum workaround in preparation
Thomas Preud'homme
thopre01@sourceware.org
Tue May 10 15:24:00 GMT 2016
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=8d9d9490142a0cd6edb7cfec820a7c8f28b88395
commit 8d9d9490142a0cd6edb7cfec820a7c8f28b88395
Author: Thomas Preud'homme <thomas.preudhomme@arm.com>
Date: Tue May 10 15:28:10 2016 +0100
Refactor Cortex-A8 erratum workaround in preparation
2016-05-10 Thomas Preud'homme <thomas.preudhomme@arm.com>
bfd/
* elf32-arm.c (enum elf32_arm_stub_type): Delete
arm_stub_a8_veneer_lwm enumerator.
(arm_stub_a8_veneer_lwm): New unsigned constant to replace
aforementioned enumerator.
(struct elf32_arm_stub_hash_entry): Delete target_addend
field and add source_value.
(struct a8_erratum_fix): Delete addend field and add target_offset.
(stub_hash_newfunc): Initialize source_value field amd remove
initialization for target_addend.
(arm_build_one_stub): Stop special casing Thumb relocations: promote
the else to being always executed, moving the
arm_stub_a8_veneer_b_cond specific code in it. Remove
stub_entry->target_addend from points_to computation.
(cortex_a8_erratum_scan): Store in a8_erratum_fix structure the offset
to target symbol from start of section rather than the offset from the
stub address.
(elf32_arm_size_stubs): Set stub_entry's source_value and target_value
fields from struct a8_erratum_fix's offset and target_offset
respectively.
(make_branch_to_a8_stub): Rename target variable to loc. Compute
veneered_insn_loc and loc using stub_entry's source_value.
Diff:
---
bfd/ChangeLog | 24 +++++++++++
bfd/elf32-arm.c | 125 +++++++++++++++++++++++---------------------------------
2 files changed, 76 insertions(+), 73 deletions(-)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index c885dd0..0e10d3a 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,29 @@
2016-05-10 Thomas Preud'homme <thomas.preudhomme@arm.com>
+ * elf32-arm.c (enum elf32_arm_stub_type): Delete
+ arm_stub_a8_veneer_lwm enumerator.
+ (arm_stub_a8_veneer_lwm): New unsigned constant to replace
+ aforementioned enumerator.
+ (struct elf32_arm_stub_hash_entry): Delete target_addend
+ field and add source_value.
+ (struct a8_erratum_fix): Delete addend field and add target_offset.
+ (stub_hash_newfunc): Initialize source_value field amd remove
+ initialization for target_addend.
+ (arm_build_one_stub): Stop special casing Thumb relocations: promote
+ the else to being always executed, moving the
+ arm_stub_a8_veneer_b_cond specific code in it. Remove
+ stub_entry->target_addend from points_to computation.
+ (cortex_a8_erratum_scan): Store in a8_erratum_fix structure the offset
+ to target symbol from start of section rather than the offset from the
+ stub address.
+ (elf32_arm_size_stubs): Set stub_entry's source_value and target_value
+ fields from struct a8_erratum_fix's offset and target_offset
+ respectively.
+ (make_branch_to_a8_stub): Rename target variable to loc. Compute
+ veneered_insn_loc and loc using stub_entry's source_value.
+
+2016-05-10 Thomas Preud'homme <thomas.preudhomme@arm.com>
+
(elf32_arm_merge_eabi_attributes): Add merging logic for
Tag_DSP_extension.
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index fa0d74f..5f6941d 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -2632,11 +2632,12 @@ enum elf32_arm_stub_type
{
arm_stub_none,
DEF_STUBS
- /* Note the first a8_veneer type. */
- arm_stub_a8_veneer_lwm = arm_stub_a8_veneer_b_cond
};
#undef DEF_STUB
+/* Note the first a8_veneer type. */
+const unsigned arm_stub_a8_veneer_lwm = arm_stub_a8_veneer_b_cond;
+
typedef struct
{
const insn_sequence* template_sequence;
@@ -2666,8 +2667,12 @@ struct elf32_arm_stub_hash_entry
bfd_vma target_value;
asection *target_section;
- /* Offset to apply to relocation referencing target_value. */
- bfd_vma target_addend;
+ /* Same as above but for the source of the branch to the stub. Used for
+ Cortex-A8 erratum workaround to patch it to branch to the stub. As
+ such, source section does not need to be recorded since Cortex-A8 erratum
+ workaround stubs are only generated when both source and target are in the
+ same section. */
+ bfd_vma source_value;
/* The instruction which caused this stub to be generated (only valid for
Cortex-A8 erratum workaround stubs at present). */
@@ -2836,7 +2841,7 @@ struct a8_erratum_fix
bfd *input_bfd;
asection *section;
bfd_vma offset;
- bfd_vma addend;
+ bfd_vma target_offset;
unsigned long orig_insn;
char *stub_name;
enum elf32_arm_stub_type stub_type;
@@ -3413,9 +3418,9 @@ stub_hash_newfunc (struct bfd_hash_entry *entry,
eh = (struct elf32_arm_stub_hash_entry *) entry;
eh->stub_sec = NULL;
eh->stub_offset = 0;
+ eh->source_value = 0;
eh->target_value = 0;
eh->target_section = NULL;
- eh->target_addend = 0;
eh->orig_insn = 0;
eh->stub_type = arm_stub_none;
eh->stub_size = 0;
@@ -4450,65 +4455,36 @@ arm_build_one_stub (struct bfd_hash_entry *gen_entry,
BFD_ASSERT (nrelocs != 0 && nrelocs <= MAXRELOCS);
for (i = 0; i < nrelocs; i++)
- if (template_sequence[stub_reloc_idx[i]].r_type == R_ARM_THM_JUMP24
- || template_sequence[stub_reloc_idx[i]].r_type == R_ARM_THM_JUMP19
- || template_sequence[stub_reloc_idx[i]].r_type == R_ARM_THM_CALL
- || template_sequence[stub_reloc_idx[i]].r_type == R_ARM_THM_XPC22)
- {
- Elf_Internal_Rela rel;
- bfd_boolean unresolved_reloc;
- char *error_message;
- enum arm_st_branch_type branch_type
- = (template_sequence[stub_reloc_idx[i]].r_type != R_ARM_THM_XPC22
- ? ST_BRANCH_TO_THUMB : ST_BRANCH_TO_ARM);
- bfd_vma points_to = sym_value + stub_entry->target_addend;
-
- rel.r_offset = stub_entry->stub_offset + stub_reloc_offset[i];
- rel.r_info = ELF32_R_INFO (0,
- template_sequence[stub_reloc_idx[i]].r_type);
- rel.r_addend = template_sequence[stub_reloc_idx[i]].reloc_addend;
-
- if (stub_entry->stub_type == arm_stub_a8_veneer_b_cond && i == 0)
- /* The first relocation in the elf32_arm_stub_a8_veneer_b_cond[]
- template should refer back to the instruction after the original
- branch. */
- points_to = sym_value;
-
- /* There may be unintended consequences if this is not true. */
- BFD_ASSERT (stub_entry->h == NULL);
-
- /* Note: _bfd_final_link_relocate doesn't handle these relocations
- properly. We should probably use this function unconditionally,
- rather than only for certain relocations listed in the enclosing
- conditional, for the sake of consistency. */
- elf32_arm_final_link_relocate (elf32_arm_howto_from_type
- (template_sequence[stub_reloc_idx[i]].r_type),
- stub_bfd, info->output_bfd, stub_sec, stub_sec->contents, &rel,
- points_to, info, stub_entry->target_section, "", STT_FUNC,
- branch_type, (struct elf_link_hash_entry *) stub_entry->h,
- &unresolved_reloc, &error_message);
- }
- else
- {
- Elf_Internal_Rela rel;
- bfd_boolean unresolved_reloc;
- char *error_message;
- bfd_vma points_to = sym_value + stub_entry->target_addend
- + template_sequence[stub_reloc_idx[i]].reloc_addend;
-
- rel.r_offset = stub_entry->stub_offset + stub_reloc_offset[i];
- rel.r_info = ELF32_R_INFO (0,
- template_sequence[stub_reloc_idx[i]].r_type);
- rel.r_addend = 0;
-
- elf32_arm_final_link_relocate (elf32_arm_howto_from_type
- (template_sequence[stub_reloc_idx[i]].r_type),
- stub_bfd, info->output_bfd, stub_sec, stub_sec->contents, &rel,
- points_to, info, stub_entry->target_section, "", STT_FUNC,
- stub_entry->branch_type,
- (struct elf_link_hash_entry *) stub_entry->h, &unresolved_reloc,
- &error_message);
- }
+ {
+ Elf_Internal_Rela rel;
+ bfd_boolean unresolved_reloc;
+ char *error_message;
+ bfd_vma points_to =
+ sym_value + template_sequence[stub_reloc_idx[i]].reloc_addend;
+
+ rel.r_offset = stub_entry->stub_offset + stub_reloc_offset[i];
+ rel.r_info = ELF32_R_INFO (0,
+ template_sequence[stub_reloc_idx[i]].r_type);
+ rel.r_addend = 0;
+
+ if (stub_entry->stub_type == arm_stub_a8_veneer_b_cond && i == 0)
+ /* The first relocation in the elf32_arm_stub_a8_veneer_b_cond[]
+ template should refer back to the instruction after the original
+ branch. We use target_section as Cortex-A8 erratum workaround stubs
+ are only generated when both source and target are in the same
+ section. */
+ points_to = stub_entry->target_section->output_section->vma
+ + stub_entry->target_section->output_offset
+ + stub_entry->source_value;
+
+ elf32_arm_final_link_relocate (elf32_arm_howto_from_type
+ (template_sequence[stub_reloc_idx[i]].r_type),
+ stub_bfd, info->output_bfd, stub_sec, stub_sec->contents, &rel,
+ points_to, info, stub_entry->target_section, "", STT_FUNC,
+ stub_entry->branch_type,
+ (struct elf_link_hash_entry *) stub_entry->h, &unresolved_reloc,
+ &error_message);
+ }
return TRUE;
#undef MAXRELOCS
@@ -5101,7 +5077,8 @@ cortex_a8_erratum_scan (bfd *input_bfd,
a8_fixes[num_a8_fixes].input_bfd = input_bfd;
a8_fixes[num_a8_fixes].section = section;
a8_fixes[num_a8_fixes].offset = i;
- a8_fixes[num_a8_fixes].addend = offset;
+ a8_fixes[num_a8_fixes].target_offset =
+ target - base_vma;
a8_fixes[num_a8_fixes].orig_insn = insn;
a8_fixes[num_a8_fixes].stub_name = stub_name;
a8_fixes[num_a8_fixes].stub_type = stub_type;
@@ -5680,9 +5657,9 @@ elf32_arm_size_stubs (bfd *output_bfd,
stub_entry->stub_offset = 0;
stub_entry->id_sec = link_sec;
stub_entry->stub_type = a8_fixes[i].stub_type;
+ stub_entry->source_value = a8_fixes[i].offset;
stub_entry->target_section = a8_fixes[i].section;
- stub_entry->target_value = a8_fixes[i].offset;
- stub_entry->target_addend = a8_fixes[i].addend;
+ stub_entry->target_value = a8_fixes[i].target_offset;
stub_entry->orig_insn = a8_fixes[i].orig_insn;
stub_entry->branch_type = a8_fixes[i].branch_type;
@@ -16277,7 +16254,7 @@ make_branch_to_a8_stub (struct bfd_hash_entry *gen_entry,
bfd_vma veneered_insn_loc, veneer_entry_loc;
bfd_signed_vma branch_offset;
bfd *abfd;
- unsigned int target;
+ unsigned int loc;
stub_entry = (struct elf32_arm_stub_hash_entry *) gen_entry;
data = (struct a8_branch_to_stub_data *) in_arg;
@@ -16288,9 +16265,11 @@ make_branch_to_a8_stub (struct bfd_hash_entry *gen_entry,
contents = data->contents;
+ /* We use target_section as Cortex-A8 erratum workaround stubs are only
+ generated when both source and target are in the same section. */
veneered_insn_loc = stub_entry->target_section->output_section->vma
+ stub_entry->target_section->output_offset
- + stub_entry->target_value;
+ + stub_entry->source_value;
veneer_entry_loc = stub_entry->stub_sec->output_section->vma
+ stub_entry->stub_sec->output_offset
@@ -16302,7 +16281,7 @@ make_branch_to_a8_stub (struct bfd_hash_entry *gen_entry,
branch_offset = veneer_entry_loc - veneered_insn_loc - 4;
abfd = stub_entry->target_section->owner;
- target = stub_entry->target_value;
+ loc = stub_entry->source_value;
/* We attempt to avoid this condition by setting stubs_always_after_branch
in elf32_arm_size_stubs if we've enabled the Cortex-A8 erratum workaround.
@@ -16363,8 +16342,8 @@ make_branch_to_a8_stub (struct bfd_hash_entry *gen_entry,
return FALSE;
}
- bfd_put_16 (abfd, (branch_insn >> 16) & 0xffff, &contents[target]);
- bfd_put_16 (abfd, branch_insn & 0xffff, &contents[target + 2]);
+ bfd_put_16 (abfd, (branch_insn >> 16) & 0xffff, &contents[loc]);
+ bfd_put_16 (abfd, branch_insn & 0xffff, &contents[loc + 2]);
return TRUE;
}
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