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Pedro Alves f077e978de x32: gdb: Fix 'call' insn relocation with qRelocInsn
Running the fast tracepoints tests against x32 gdbserver exposes a
latent bug.  E.g.,:

 (gdb)
 continue
 Continuing.
 Reading /media/sf_host-pedro/gdb/mygit/build-ubuntu-x32/gdb/testsuite/outputs/gdb.trace/change-loc/change-loc-2.sl from remote target...

 Thread 1 "change-loc" received signal SIGSEGV, Segmentation fault.
 func4 () at /home/pedro/gdb/src/gdb/testsuite/gdb.trace/change-loc.h:24
 24      }
 (gdb) FAIL: gdb.trace/change-loc.exp: 1 ftrace: continue to marker 2

The test sets a fast tracepoint on a shared library.  On x32, shared
libraries end up loaded somewhere in the upper 2GB of the 4GB address
space x32 has access to.  When gdbserver needs to copy an instruction
to execute it in the jump pad, it asks gdb to relocate/adjust it, with
the qRelocInsn packet.  gdb converts "call" instructions into a "push
$<2GB-4GB addr> + jmp" sequence, however, the "pushq" instruction sign
extends its operand, so later when the called function returns, it
returns to an incorrectly sign-extended address.  E.g.,
0xfffffffffabc0000 instead of 0xfabc0000, resulting in the
segmentation fault.

Fix this by converting calls at such addresses to "sub + mov + jmp"
sequences instead.

gdb/ChangeLog:
2016-08-19  Pedro Alves  <palves@redhat.com>

	* amd64-tdep.c (amd64_relocate_instruction) <callq>: Handle return
	addresses over 0x7fffffff.
2016-08-19 12:12:51 +01:00
bfd Place .shstrtab section after .symtab and .strtab, thus restoring monotonically increasing section offsets. 2016-08-19 09:16:30 +01:00
binutils Place .shstrtab section after .symtab and .strtab, thus restoring monotonically increasing section offsets. 2016-08-19 09:16:30 +01:00
config
cpu
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gas Place .shstrtab section after .symtab and .strtab, thus restoring monotonically increasing section offsets. 2016-08-19 09:16:30 +01:00
gdb x32: gdb: Fix 'call' insn relocation with qRelocInsn 2016-08-19 12:12:51 +01:00
gold Fix extraneous complaints about missing expected TLS relocation (i386). 2016-08-17 10:53:31 -07:00
gprof
include
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ld Enable relro by default for AArch64, ARM and SCORE. 2016-08-19 09:27:52 +01:00
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sim sim: m68hc11: use standard STATIC_INLINE helper 2016-08-16 06:12:39 -07:00
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.