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[PATCH] x86: Keep __patchable_function_entries sections with --gc-sections
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: binutils at sourceware dot org
- Date: Sat, 1 Feb 2020 08:26:13 -0800
- Subject: [PATCH] x86: Keep __patchable_function_entries sections with --gc-sections
After all text sections have been garbage collected, if a
__patchable_function_entries section references a section which
wasn't marked, mark it with SEC_EXCLUDE and return NULL. Otherwise,
keep it.
Should it be handled in _bfd_elf_gc_mark_extra_sections?
H.J.
---
bfd/
PR ld/25490
* elfxx-x86.c (_bfd_x86_elf_gc_mark_hook): Handle
__patchable_function_entries sections.
(_bfd_x86_elf_gc_mark_extra_sections): New function.
* elfxx-x86.h (_bfd_x86_elf_gc_mark_extra_sections): New.
(elf_backend_gc_mark_extra_sections): Likewise.
ld/
PR ld/25490
* testsuite/ld-i386/i386.exp: Run PR ld/25490 tests.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr25490-1.d: Likewise.
* testsuite/ld-i386/pr25490-2a.d: Likewise.
* testsuite/ld-i386/pr25490-2b.d: Likewise.
* testsuite/ld-x86-64/pr25490-1-x32.d: Likewise.
* testsuite/ld-x86-64/pr25490-1.d: Likewise.
* testsuite/ld-x86-64/pr25490-1.s: Likewise.
* testsuite/ld-x86-64/pr25490-2.s: Likewise.
* testsuite/ld-x86-64/pr25490-2a-x32.d: Likewise.
* testsuite/ld-x86-64/pr25490-2a.d: Likewise.
* testsuite/ld-x86-64/pr25490-2b-x32.d: Likewise.
* testsuite/ld-x86-64/pr25490-2b.d: Likewise.
---
bfd/elfxx-x86.c | 44 +++++++++++++++++++++++++
bfd/elfxx-x86.h | 5 +++
ld/testsuite/ld-i386/i386.exp | 3 ++
ld/testsuite/ld-i386/pr25490-1.d | 8 +++++
ld/testsuite/ld-i386/pr25490-2a.d | 8 +++++
ld/testsuite/ld-i386/pr25490-2b.d | 9 +++++
ld/testsuite/ld-x86-64/pr25490-1-x32.d | 8 +++++
ld/testsuite/ld-x86-64/pr25490-1.d | 7 ++++
ld/testsuite/ld-x86-64/pr25490-1.s | 13 ++++++++
ld/testsuite/ld-x86-64/pr25490-2.s | 26 +++++++++++++++
ld/testsuite/ld-x86-64/pr25490-2a-x32.d | 8 +++++
ld/testsuite/ld-x86-64/pr25490-2a.d | 8 +++++
ld/testsuite/ld-x86-64/pr25490-2b-x32.d | 9 +++++
ld/testsuite/ld-x86-64/pr25490-2b.d | 9 +++++
ld/testsuite/ld-x86-64/x86-64.exp | 6 ++++
15 files changed, 171 insertions(+)
create mode 100644 ld/testsuite/ld-i386/pr25490-1.d
create mode 100644 ld/testsuite/ld-i386/pr25490-2a.d
create mode 100644 ld/testsuite/ld-i386/pr25490-2b.d
create mode 100644 ld/testsuite/ld-x86-64/pr25490-1-x32.d
create mode 100644 ld/testsuite/ld-x86-64/pr25490-1.d
create mode 100644 ld/testsuite/ld-x86-64/pr25490-1.s
create mode 100644 ld/testsuite/ld-x86-64/pr25490-2.s
create mode 100644 ld/testsuite/ld-x86-64/pr25490-2a-x32.d
create mode 100644 ld/testsuite/ld-x86-64/pr25490-2a.d
create mode 100644 ld/testsuite/ld-x86-64/pr25490-2b-x32.d
create mode 100644 ld/testsuite/ld-x86-64/pr25490-2b.d
diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index fc783b0e988..ec2ab0ce72b 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -2110,10 +2110,54 @@ _bfd_x86_elf_gc_mark_hook (asection *sec,
case R_X86_64_GNU_VTENTRY:
return NULL;
}
+ else if (CONST_STRNEQ (bfd_section_name (sec),
+ "__patchable_function_entries"))
+ {
+ /* After all text sections have been garbage collected, if a
+ __patchable_function_entries section references a section
+ which wasn't marked, mark it with SEC_EXCLUDE and return
+ NULL. */
+ asection *tsec = bfd_section_from_elf_index (sec->owner,
+ sym->st_shndx);
+ if (!tsec->gc_mark)
+ {
+ sec->flags |= SEC_EXCLUDE;
+ return NULL;
+ }
+ }
return _bfd_elf_gc_mark_hook (sec, info, rel, h, sym);
}
+/* Prevent __patchable_function_entries sections from being discarded
+ with --gc-sections. */
+
+bfd_boolean
+_bfd_x86_elf_gc_mark_extra_sections (struct bfd_link_info *info,
+ elf_gc_mark_hook_fn gc_mark_hook)
+{
+ bfd *sub;
+
+ _bfd_elf_gc_mark_extra_sections (info, gc_mark_hook);
+
+ for (sub = info->input_bfds; sub != NULL; sub = sub->link.next)
+ {
+ asection *o;
+
+ for (o = sub->sections; o != NULL; o = o->next)
+ if (!o->gc_mark
+ && (o->flags & SEC_EXCLUDE) == 0
+ && CONST_STRNEQ (bfd_section_name (o),
+ "__patchable_function_entries"))
+ {
+ if (!_bfd_elf_gc_mark (info, o, gc_mark_hook))
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+}
+
static bfd_vma
elf_i386_get_plt_got_vma (struct elf_x86_plt *plt_p ATTRIBUTE_UNUSED,
bfd_vma off,
diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h
index bef17dc2bac..1e43f1d786c 100644
--- a/bfd/elfxx-x86.h
+++ b/bfd/elfxx-x86.h
@@ -688,6 +688,9 @@ extern asection * _bfd_x86_elf_gc_mark_hook
(asection *, struct bfd_link_info *, Elf_Internal_Rela *,
struct elf_link_hash_entry *, Elf_Internal_Sym *);
+extern bfd_boolean _bfd_x86_elf_gc_mark_extra_sections
+ (struct bfd_link_info *, elf_gc_mark_hook_fn);
+
extern long _bfd_x86_elf_get_synthetic_symtab
(bfd *, long, long, bfd_vma, struct elf_x86_plt [], asymbol **,
asymbol **);
@@ -737,6 +740,8 @@ extern void _bfd_x86_elf_link_fixup_ifunc_symbol
_bfd_x86_elf_adjust_dynamic_symbol
#define elf_backend_gc_mark_hook \
_bfd_x86_elf_gc_mark_hook
+#define elf_backend_gc_mark_extra_sections \
+ _bfd_x86_elf_gc_mark_extra_sections
#define elf_backend_omit_section_dynsym \
_bfd_elf_omit_section_dynsym_all
#define elf_backend_parse_gnu_properties \
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index 7bb3636d3b0..68a43e3c35d 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -496,6 +496,9 @@ run_dump_test "pr23930"
run_dump_test "pr24322a"
run_dump_test "pr24322b"
run_dump_test "align-branch-1"
+run_dump_test "pr25490-1"
+run_dump_test "pr25490-2a"
+run_dump_test "pr25490-2b"
if { !([istarget "i?86-*-linux*"]
|| [istarget "i?86-*-gnu*"]
diff --git a/ld/testsuite/ld-i386/pr25490-1.d b/ld/testsuite/ld-i386/pr25490-1.d
new file mode 100644
index 00000000000..67cc5e86ec2
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr25490-1.d
@@ -0,0 +1,8 @@
+#source: ../ld-x86-64/pr25490-1.s
+#as: --32
+#ld: --gc-sections -melf_i386
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] __patchable_function_entries +PROGBITS +[0-9a-f]+ +[0-9a-f]+000 +0+4 +00 +WA +0 +0 +1
+#pass
diff --git a/ld/testsuite/ld-i386/pr25490-2a.d b/ld/testsuite/ld-i386/pr25490-2a.d
new file mode 100644
index 00000000000..5096252829f
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr25490-2a.d
@@ -0,0 +1,8 @@
+#source: ../ld-x86-64/pr25490-2.s
+#as: --32
+#ld: --gc-sections -melf_i386
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] __patchable_function_entries._start +PROGBITS +[0-9a-f]+ +[0-9a-f]+000 +0+4 +00 +WA +0 +0 +1
+#pass
diff --git a/ld/testsuite/ld-i386/pr25490-2b.d b/ld/testsuite/ld-i386/pr25490-2b.d
new file mode 100644
index 00000000000..3f9cab548be
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr25490-2b.d
@@ -0,0 +1,9 @@
+#source: ../ld-x86-64/pr25490-2.s
+#as: --32
+#ld: --gc-sections -melf_i386
+#readelf: -SW
+
+#failif
+#...
+ +\[ *[0-9]+\] __patchable_function_entries.bar +PROGBITS +.*
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr25490-1-x32.d b/ld/testsuite/ld-x86-64/pr25490-1-x32.d
new file mode 100644
index 00000000000..65bc2bee28c
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-1-x32.d
@@ -0,0 +1,8 @@
+#source: pr25490-1.s
+#as: --x32
+#ld: --gc-sections -melf32_x86_64
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] __patchable_function_entries +PROGBITS +[0-9a-f]+ +[0-9a-f]+000 +0+4 +00 +WA +0 +0 +1
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr25490-1.d b/ld/testsuite/ld-x86-64/pr25490-1.d
new file mode 100644
index 00000000000..dc1d912076b
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-1.d
@@ -0,0 +1,7 @@
+#as: --64
+#ld: --gc-sections -melf_x86_64
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] __patchable_function_entries +PROGBITS +[0-9a-f]+ +[0-9a-f]+000 +0+8 +00 +WA +0 +0 +1
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr25490-1.s b/ld/testsuite/ld-x86-64/pr25490-1.s
new file mode 100644
index 00000000000..21123ad8aa0
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-1.s
@@ -0,0 +1,13 @@
+ .text
+ .p2align 4
+ .globl _start
+ .type _start, %function
+_start:
+ .section __patchable_function_entries,"aw",%progbits
+ .dc.a .LPFE1
+ .text
+.LPFE1:
+ nop
+ ret
+ .size _start, .-_start
+ .section .note.GNU-stack,"",%progbits
diff --git a/ld/testsuite/ld-x86-64/pr25490-2.s b/ld/testsuite/ld-x86-64/pr25490-2.s
new file mode 100644
index 00000000000..1f8df870316
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-2.s
@@ -0,0 +1,26 @@
+ .text
+ .p2align 4
+ .section .text.bar,"ax",%progbits
+ .globl bar
+ .type bar, %function
+bar:
+ .section __patchable_function_entries.bar,"aw",%progbits
+ .dc.a .LPFE1
+ .section .text.bar,"ax",%progbits
+.LPFE1:
+ nop
+ ret
+ .size bar, .-bar
+ .p2align 4
+ .section .text._start,"ax",%progbits
+ .globl _start
+ .type _start, %function
+_start:
+ .section __patchable_function_entries._start,"aw",%progbits
+ .dc.a .LPFE2
+ .section .text._start,"ax",%progbits
+.LPFE2:
+ nop
+ ret
+ .size _start, .-_start
+ .section .note.GNU-stack,"",%progbits
diff --git a/ld/testsuite/ld-x86-64/pr25490-2a-x32.d b/ld/testsuite/ld-x86-64/pr25490-2a-x32.d
new file mode 100644
index 00000000000..2029029a0f3
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-2a-x32.d
@@ -0,0 +1,8 @@
+#source: pr25490-2.s
+#as: --x32
+#ld: --gc-sections -melf32_x86_64
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] __patchable_function_entries._start +PROGBITS +[0-9a-f]+ +[0-9a-f]+000 +0+4 +00 +WA +0 +0 +1
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr25490-2a.d b/ld/testsuite/ld-x86-64/pr25490-2a.d
new file mode 100644
index 00000000000..a5f0b141c87
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-2a.d
@@ -0,0 +1,8 @@
+#source: pr25490-2.s
+#as: --64
+#ld: --gc-sections -melf_x86_64
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] __patchable_function_entries._start +PROGBITS +[0-9a-f]+ +[0-9a-f]+000 +0+8 +00 +WA +0 +0 +1
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr25490-2b-x32.d b/ld/testsuite/ld-x86-64/pr25490-2b-x32.d
new file mode 100644
index 00000000000..a9fe6ba6b3c
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-2b-x32.d
@@ -0,0 +1,9 @@
+#source: pr25490-2.s
+#as: --x32
+#ld: --gc-sections -melf32_x86_64
+#readelf: -SW
+
+#failif
+#...
+ +\[ *[0-9]+\] __patchable_function_entries.bar +PROGBITS +.*
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr25490-2b.d b/ld/testsuite/ld-x86-64/pr25490-2b.d
new file mode 100644
index 00000000000..5eb933f5b36
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr25490-2b.d
@@ -0,0 +1,9 @@
+#source: pr25490-2.s
+#as: --64
+#ld: --gc-sections -melf_x86_64
+#readelf: -SW
+
+#failif
+#...
+ +\[ *[0-9]+\] __patchable_function_entries.bar +PROGBITS +.*
+#pass
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index c78b0fd7576..e30b21d53d4 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -467,6 +467,12 @@ run_dump_test "pr25416-2a"
run_dump_test "pr25416-2b"
run_dump_test "pr25416-3"
run_dump_test "pr25416-4"
+run_dump_test "pr25490-1"
+run_dump_test "pr25490-1-x32"
+run_dump_test "pr25490-2a"
+run_dump_test "pr25490-2a-x32"
+run_dump_test "pr25490-2b"
+run_dump_test "pr25490-2b-x32"
if { ![istarget "x86_64-*-linux*"] && ![istarget "x86_64-*-nacl*"]} {
return
--
2.24.1