Binutils with MCST patches
Go to file
Antoine Tremblay 9b4c5f878f Remove support for thread events without PTRACE_EVENT_CLONE in GDBServer.
This patch removes support for thread events if PTRACE_EVENT_CLONE is not
supported in GDBServer.

Before, on systems that did not support PTRACE_EVENT_CLONE, both GDB and
GDBServer coordinated with libthread_db.so to insert breakpoints at magic
locations in libpthread.so, in order to break at thread creation and thread
death.

Simple software single stepping support was implemented to step over these
breakpoints in case there was no hardware single stepping support. However,
these simple software single stepping implementations were not fit for any other
use as discussed in :
https://sourceware.org/ml/gdb-patches/2015-04/msg01110.html

These too simple implementations conflict with ongoing work to make proper
implementations of software single stepping in GDBServer.

The problem is that if some implementations are correct and others are not and
only there for the thread magic breakpoint, we can't enable features based
solely software single step support since some would be broken.

To keep the incorrect implementations and allow the new proper ones at the same
time we would need to implement fallback code and it quickly becomes ugly and
confusing with multiple checks for legacy software single step or proper
software single step.

However, PTRACE_EVENT_CLONE was first introduced in Linux 2.5.46,
released in November 2002.

So I think it's reasonable to just remove support for kernels that don't support
PTRACE_EVENT_CLONE, and sidestep the libthread_db breakpoints issues entirely.

This thread on the mailling list discusses the issue :
https://sourceware.org/ml/gdb/2015-10/msg00078.html

No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }

gdb/gdbserver/ChangeLog:

	* linux-low.c (linux_look_up_symbols): Don't call
	linux_supports_traceclone.
	* linux-low.h (thread_db_init): Remove use_events argument.
	* thread-db.c (thread_db_use_event): Remove global variable.
	(struct thread_db) <td_thr_event_enable_p>: Remove field.
	(struct thread_db) <td_create_bp>: Remove field.
	(thread_db_create_event): Remove function.
	(thread_db_enable_reporting): Likewise.
	(find_one_thread): Don't check for thread_db_use_events.
	(attach_thread): Likewise.
	(thread_db_load_search): Remove td_thr_event_enable_p initialization.
	(try_thread_db_load_1): Don't check for thread_db_use_events.
	(thread_db_init): Remove use_events argument and thread events
	handling.
	(remove_thread_event_breakpoints): Remove function.
	(thread_db_detach): Remove call to remove_thred_event_breakpoints.
2015-11-30 15:18:57 -05:00
bfd Automatic date update in version.in 2015-11-30 00:00:08 +00:00
binutils objdump: Handle 32-bit base address in debug_ranges / debug_loc. 2015-11-30 13:28:26 +00:00
config libsanitizer merge from upstream r250806, compiler part. 2015-11-28 16:39:32 +00:00
cpu
elfcpp
etc
gas [AArch64][PATCH 3/3] Add floating-point FP16 instructions 2015-11-27 16:32:21 +00:00
gdb Remove support for thread events without PTRACE_EVENT_CLONE in GDBServer. 2015-11-30 15:18:57 -05:00
gold Adjust local symbol value in relocatable link to be relative to section. 2015-11-25 08:50:41 -08:00
gprof Bump version to 2.26.51 2015-11-14 16:24:39 -08:00
include Port libvtv to Solaris 2015-11-28 16:39:32 +00:00
intl
ld MIPS/LD: Fix little-endian mti' and img' ELF emulations 2015-11-20 16:16:40 +00:00
libdecnumber
libiberty PR other/61321 - demangler crash on casts in template parameters 2015-11-28 16:39:31 +00:00
opcodes [AArch64][PATCH 3/3] Add floating-point FP16 instructions 2015-11-27 16:32:21 +00:00
readline
sim Add an AArch64 simulator to GDB. 2015-11-24 08:47:59 +00:00
texinfo
zlib Import zlib 1.2.8 with local change merged in. 2015-11-25 15:14:47 -08:00
.cvsignore
.gitattributes
.gitignore
ChangeLog binutils: add support for arm-*-darwin and aarch64-*-darwin. 2015-11-20 14:53:06 +01:00
compile
config-ml.in
config.guess
config.rpath
config.sub
configure binutils: add support for arm-*-darwin and aarch64-*-darwin. 2015-11-20 14:53:06 +01:00
configure.ac binutils: add support for arm-*-darwin and aarch64-*-darwin. 2015-11-20 14:53:06 +01:00
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
Makefile.def
Makefile.in
Makefile.tpl
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
README
README-maintainer-mode
setup.com
src-release.sh
symlink-tree
ylwrap

		   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.