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Emilio Castillo 7bb65dd434 x86 : fxsave and fxrestore missing template code 
This patch corrects the FXSAVE and FXRSTOR Macroops.  The actual code used for
saving/restore the FP registers is in the file but it was not used.

The FXSAVE and FXRSTOR instructions are used in the kernel for saving and
loading the state of the mmx,xmm and fpu registers.

This operation is triggered in FS by issuing a Device Not Available Fault.  The
cr0 register has a TS flag that is set upon each context change. Every time a
task access any FP related register (SIMD as well) if the TS flag is set to
one, the device not available fault is issued.  The kernel saves the current
state of the registers, and restore the previous state of the currently running
task.

Right now Gem5 lacks of this capability. the Device Not Available Fault is
never issued, leading to several problems when different threads share the same
CPU and SMT is not used. The PARSEC Ferret benchmark is an example of this
behavior.

In order to test this a hack in the atomic cpu code was done to detect if a
static instruction has any FP operands and the cr0 reg TS bit is set.  This
check must be done in the ISA dependent code. But it seems to be tricky to
access the cr0 register while executing an instruction.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2015-01-10 14:30:53 -06:00
build_opts alpha: Stop using 'inorder' and rely entirely on 'minor' 2014-09-03 07:42:56 -04:00
configs arm: fix build_drive_system when not using default options 2015-01-03 17:51:48 -06:00
ext ext: Bump DRAMPower to avoid compilation issues 2014-10-20 18:03:53 -04:00
src x86 : fxsave and fxrestore missing template code 2015-01-10 14:30:53 -06:00
system arm: Add support for ARMv8 (AArch64 & AArch32) 2014-01-24 15:29:34 -06:00
tests stats: x86: Update stats for the CPUID change. 2015-01-07 00:31:09 -08:00
util config: Fix to SystemC example's event handling 2014-12-02 06:08:09 -05:00
.hgignore ext: Add a McPAT regression tester 2014-06-04 07:48:20 -07:00
.hgtags Added tag stable_2014_12_14 for changeset bdb307e8be54 2014-12-14 16:21:04 -06:00
COPYING copyright: Add code for finding all copyright blocks and create a COPYING file 2011-06-02 17:36:07 -07:00
LICENSE copyright: Add code for finding all copyright blocks and create a COPYING file 2011-06-02 17:36:07 -07:00
README misc: README direct to website for dependencies 2014-08-26 10:12:04 -04:00
SConstruct scons: Make the USE_KVM variable available in C++. 2014-12-22 16:49:24 -08:00

README 

This is the gem5 simulator.

The main website can be found at http://www.gem5.org

A good starting point is http://www.gem5.org/Introduction, and for
more information about building the simulator and getting started
please see http://www.gem5.org/Documentation and
http://www.gem5.org/Tutorials.

To build gem5, you will need the following software: g++ or clang,
Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4,
and lastly protobuf if you want trace capture and playback
support. Please see http://www.gem5.org/Dependencies for more details
concerning the minimum versions of the aforementioned tools.

Once you have all dependencies resolved, type 'scons
build/<ARCH>/gem5.opt' where ARCH is one of ALPHA, ARM, NULL, MIPS,
POWER, SPARC, or X86. This will build an optimized version of the gem5
binary (gem5.opt) for the the specified architecture. See
http://www.gem5.org/Build_System for more details and options.

With the simulator built, have a look at
http://www.gem5.org/Running_gem5 for more information on how to use
gem5.

The basic source release includes these subdirectories:
   - configs: example simulation configuration scripts
   - ext: less-common external packages needed to build gem5
   - src: source code of the gem5 simulator
   - system: source for some optional system software for simulated systems
   - tests: regression tests
   - util: useful utility programs and files

To run full-system simulations, you will need compiled system firmware
(console and PALcode for Alpha), kernel binaries and one or more disk
images. Please see the gem5 download page for these items at
http://www.gem5.org/Download

If you have questions, please send mail to gem5-users@gem5.org

Enjoy using gem5 and please share your modifications and extensions.