binutils-gdb/ld/testsuite/ld-x86-64/tlsdesc.pd
H.J. Lu bf54968b12 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.
2018-03-25 05:02:32 -07:00

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#source: tlsdesc.s
#source: tlspic2.s
#as: --64
#ld: -shared -melf_x86_64 --no-ld-generated-unwind-info
#objdump: -drj.plt
#target: x86_64-*-*
.*: +file format elf64-x86-64
Disassembly of section .plt:
[0-9a-f]+ <.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 <.*>