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[binutils-gdb/binutils-2_30-branch] x86-64: Add ENDBR64 to the TLSDESC PLT entry
- From: H.J.Lu <hjl at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 26 Mar 2018 10:57:29 -0000
- Subject: [binutils-gdb/binutils-2_30-branch] x86-64: Add ENDBR64 to the TLSDESC PLT entry
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=963e88c631ad5878d70d055fd8597c83279efe66
commit 963e88c631ad5878d70d055fd8597c83279efe66
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Mon Mar 26 03:57:01 2018 -0700
x86-64: Add ENDBR64 to the TLSDESC PLT entry
The TLSDESC entry in a lazy procedure linkage table is called indirectly
with "callq *(%rax)". This patch adds an ENDBR64 to support indirect
branch tracking in Intel CET. The TLSDESC PLT entry now looks like:
0xf3, 0x0f, 0x1e, 0xfa, /* endbr64 */
0xff, 0x35, 8, 0, 0, 0, /* pushq GOT+8(%rip) */
0xff, 0x25, 16, 0, 0, 0 /* jmpq *GOT+TDG(%rip) */
The BND prefix isn't needed since MPX isn't used for TLSDESC.
bfd/
PR ld/23000
* elf64-x86-64.c (elf_x86_64_finish_dynamic_sections): Add
ENDBR64 to the TLSDESC PLT entry.
ld/
PR ld/23000
* testsuite/ld-x86-64/tlsdesc.pd: Updated.
(cherry picked from commit bf54968b128a2133174d81c438d402ecfaf83042)
Diff:
---
bfd/ChangeLog | 9 +++++++++
bfd/elf64-x86-64.c | 32 +++++++++++++++++++-------------
ld/ChangeLog | 8 ++++++++
ld/testsuite/ld-x86-64/tlsdesc.pd | 2 +-
4 files changed, 37 insertions(+), 14 deletions(-)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 3c9e08b..b6b05ec 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2018-03-26 H.J. Lu <hongjiu.lu@intel.com>
+
+ Backport from master branch
+ 2018-03-25 H.J. Lu <hongjiu.lu@intel.com>
+
+ PR ld/23000
+ * elf64-x86-64.c (elf_x86_64_finish_dynamic_sections): Add
+ ENDBR64 to the TLSDESC PLT entry.
+
2018-03-21 Alan Modra <amodra@gmail.com>
Apply from master
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index ba4f47b..30e07c4 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -4393,15 +4393,23 @@ elf_x86_64_finish_dynamic_sections (bfd *output_bfd,
if (htab->tlsdesc_plt)
{
+ /* The TLSDESC entry in a lazy procedure linkage table. */
+ static const bfd_byte tlsdesc_plt_entry[LAZY_PLT_ENTRY_SIZE] =
+ {
+ 0xf3, 0x0f, 0x1e, 0xfa, /* endbr64 */
+ 0xff, 0x35, 8, 0, 0, 0, /* pushq GOT+8(%rip) */
+ 0xff, 0x25, 16, 0, 0, 0 /* jmpq *GOT+TDG(%rip) */
+ };
+
bfd_put_64 (output_bfd, (bfd_vma) 0,
htab->elf.sgot->contents + htab->tlsdesc_got);
memcpy (htab->elf.splt->contents + htab->tlsdesc_plt,
- htab->lazy_plt->plt0_entry,
- htab->lazy_plt->plt0_entry_size);
+ tlsdesc_plt_entry, LAZY_PLT_ENTRY_SIZE);
- /* Add offset for pushq GOT+8(%rip), since the
- instruction uses 6 bytes subtract this value. */
+ /* Add offset for pushq GOT+8(%rip), since ENDBR64 uses 4
+ bytes and the instruction uses 6 bytes, subtract these
+ values. */
bfd_put_32 (output_bfd,
(htab->elf.sgotplt->output_section->vma
+ htab->elf.sgotplt->output_offset
@@ -4409,14 +4417,13 @@ elf_x86_64_finish_dynamic_sections (bfd *output_bfd,
- htab->elf.splt->output_section->vma
- htab->elf.splt->output_offset
- htab->tlsdesc_plt
- - 6),
+ - 4 - 6),
(htab->elf.splt->contents
+ htab->tlsdesc_plt
- + htab->lazy_plt->plt0_got1_offset));
- /* Add offset for the PC-relative instruction accessing
- GOT+TDG, where TDG stands for htab->tlsdesc_got,
- subtracting the offset to the end of that
- instruction. */
+ + 4 + 2));
+ /* Add offset for indirect branch via GOT+TDG, where TDG
+ stands for htab->tlsdesc_got, subtracting the offset
+ to the end of that instruction. */
bfd_put_32 (output_bfd,
(htab->elf.sgot->output_section->vma
+ htab->elf.sgot->output_offset
@@ -4424,10 +4431,9 @@ elf_x86_64_finish_dynamic_sections (bfd *output_bfd,
- htab->elf.splt->output_section->vma
- htab->elf.splt->output_offset
- htab->tlsdesc_plt
- - htab->lazy_plt->plt0_got2_insn_end),
+ - 4 - 6 - 6),
(htab->elf.splt->contents
- + htab->tlsdesc_plt
- + htab->lazy_plt->plt0_got2_offset));
+ + htab->tlsdesc_plt + 4 + 6 + 2));
}
}
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 6123078..05223f4 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,11 @@
+2018-03-26 H.J. Lu <hongjiu.lu@intel.com>
+
+ Backport from master branch
+ 2018-03-25 H.J. Lu <hongjiu.lu@intel.com>
+
+ PR ld/23000
+ * testsuite/ld-x86-64/tlsdesc.pd: Updated.
+
2018-03-20 Roland McGrath <mcgrathr@google.com>
* testsuite/ld-elf/elf.exp (pr20995-2): XFAIL on aarch64*-*-elf*,
diff --git a/ld/testsuite/ld-x86-64/tlsdesc.pd b/ld/testsuite/ld-x86-64/tlsdesc.pd
index 0fa36f3..08b4fa3 100644
--- a/ld/testsuite/ld-x86-64/tlsdesc.pd
+++ b/ld/testsuite/ld-x86-64/tlsdesc.pd
@@ -13,7 +13,7 @@ Disassembly of section .plt:
[0-9a-f]+: ff 35 .. .. 20 00 pushq .*\(%rip\) # 201358 <_GLOBAL_OFFSET_TABLE_\+0x8>
[0-9a-f]+: ff 25 .. .. 20 00 jmpq \*.*\(%rip\) # 201360 <_GLOBAL_OFFSET_TABLE_\+0x10>
[0-9a-f]+: 0f 1f 40 00 nopl 0x0\(%rax\)
+ [0-9a-f]+: f3 0f 1e fa endbr64
[0-9a-f]+: ff 35 .. .. 20 00 pushq .*\(%rip\) # 201358 <_GLOBAL_OFFSET_TABLE_\+0x8>
[0-9a-f]+: ff 25 .. .. 20 00 jmpq \*.*\(%rip\) # 201348 <.*>
- [0-9a-f]+: 0f 1f 40 00 nopl 0x0\(%rax\)