arch, base, cpu, gpu, sim: Merge getMemProxy and getVirtProxy.

These two functions were performing the same function but had two
different names for historical reasons. This change merges them
together, keeping the getVirtProxy name to be consistent with the
getPhysProxy method used to get a non-translating proxy port.

Change-Id: Idd83c6b899f9343795075b030ccbc723a79e52a4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18581
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

sim-se: add a release parameter to Process.py

Set the default release to that single value for all ISAs.

glibc has checks for the kernel version based on uname, and refuses
to start any syscall emulation programs if those checks don't pass with
error:

FATAL: kernel too old

The ideal solution to this problem is to actually implement all missing
system calls for the required kernel version and bumping the release
accordingly.

However, it is very hard to implement all missing syscalls and verify
compliance.

Previously, we have simply bumped the version manually from time to
time when major glibc versions started breaking.

This commit alleviates the problem in two ways.

Firstly, having a single kernel version for all versions means that it is
easier to bump all versions at once.

Secondly, it makes it is possible to set the release with a parameter,
which in turn can be set from the command line with:

se.py --param 'system.cpu[:].workload[:].release = "4.18.0"'

Change-Id: I9e3c31073bfe68735f7b0775c8e299aa62b98222
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17849
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch, base, dev, sim: Remove now unnecessary casts from PortProxy methods.

Change-Id: Ia73b2d86a10d02fa09c924a4571477bb5f200eb7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18572
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

sim-se: change syscall function signature

The system calls had four parameters. One of the parameters
is ThreadContext and another is Process. The ThreadContext
holds the value of the current process so the Process parameter
is redundant since the system call functions already have
indirect access.

With the old API, it is possible to call into the functions with
the wrong supplied Process which could end up being a confusing
error.

This patch removes the redundancy by forcing access through the
ThreadContext field within each system call.

Change-Id: Ib43d3f65824f6d425260dfd9f67de1892b6e8b7c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/12299
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arm: Add an object file loader for linux and freebsd.

Change-Id: Ie5fd187a4897aa608ffc12278b23d3ee8c0f323c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18585
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

sim-se: update the arm kernel version

This change is needed to run cpu tests with ARM binaries
compiled with newer linux kernel headers

Change-Id: I6cbf132c38d4b18f971ee32272ddb6a5a791a625
Signed-off-by: Ayaz Akram <yazakram@ucdavis.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/15855
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

sim-se: add syscalls related to polling

Fix poll so that it will use the syscall retry capability
instead of causing a blocking call.

Add the accept and wait4 system calls.

Add polling to read to remove deadlocks that occur in the
event queue that are caused by blocking system calls.

Modify the write system call to return an error number in
case of error.

Change-Id: I0b4091a2e41e4187ebf69d63e0088f988f37d5da
Reviewed-on: https://gem5-review.googlesource.com/c/12115
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

sim-se, arch-arm: Add support for getdents64

Change-Id: Ib27950144d4c9802ffb842db98aec9e433ccbfc5
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Cc: Giacomo Travaglini <giacomo.travaglini@arm.com>
Cc: Javier Setoain <javier.setoain@arm.com>
Cc: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15438
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

arch-arm, sim-se: Add support for TLS in clone

Change-Id: I1f78dce05a48a2e3adfaf027cd38ab55507b9611
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Cc: Giacomo Travaglini <giacomo.travaglini@arm.com>
Cc: Javier Setoain <javier.setoain@arm.com>
Cc: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15437
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>

arch-arm, sim-se: Fix incorrect SP handling in clone

The clone syscall is currently broken on aarch64 since the aarch64
code uses an incorrect SP register. Fix this by storing the new stack
pointer in SP_EL0 instead of R13.

Change-Id: Ie17990b4f359608e3b53e5bf625eca53769a6653
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Cc: Giacomo Travaglini <giacomo.travaglini@arm.com>
Cc: Javier Setoain <javier.setoain@arm.com>
Cc: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15436
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>

sim-se: Refactor clone to avoid most ifdefs

Some parts of clone are architecture dependent. In some cases, we are
able to use architecture-specific helper functions or register
aliases. However, there is still some architecture-specific that is
protected by ifdefs in the common clone implementation.

Move these architecture-specific bits to the architecture-specific OS
class instead to avoid these ifdefs and make the code a bit more
readable.

Change-Id: Ia0903d738d0ba890863bddfa77e3b717db7f45de
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Cc: Giacomo Travaglini <giacomo.travaglini@arm.com>
Cc: Javier Setoain <javier.setoain@arm.com>
Cc: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15435
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>

arch-arm, sim-se: Wire up syscalls needed for pthreads

Change-Id: I8da5e3e0d7dc5d31ac82ed2045109d6d73cbf99d
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Cc: Giacomo Travaglini <giacomo.travaglini@arm.com>
Cc: Javier Setoain <javier.setoain@arm.com>
Cc: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15415
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>

syscall_emul: implement arm openat

This is especially important because the Ubuntu 18.04 packaged
arm-linux-gnueabihf-gcc uses the system call on the program initialization,
which leads all programs to fail with:

fatal: syscall openat (#322) unimplemented.

Change-Id: I5596162ad19644df7b6d21f2a46acc07030001ae
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13004
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

syscall_emul: update arm uname release to 3.7.0+

Trying to compile an ARM C hello world with arm-linux-gnueabihf-gcc from
Ubuntu 16.04 leads to a runtime failure with se.py:

FATAL: kernel too old

because the glibc tests if the kernel is at least 3.2.0, and gem5 was
reporting 3.0.0.

Furthermore, it is hard to obtain such toolchain at all: for example
crosstool-NG currently only allows for minimum kernels above 3.2.0.

3.7.0+ was chosen to match the aarch64 value, as it is likely that the
level of support will be very similar.

This commit does not guarantee that full 3.7.0 is supported, but it is
not likely that we had full 3.0.0 support previously either.

However, it is more likely that such support will be eventually achieved
if users can at least try out their programs and implement the missing
system calls as they are found.

Change-Id: I8df3763ae49788a6cb11cb0920e8202cd56b0f09
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/12986
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

sim: Remove _numContexts member in System class

A System object has a _numContexts member variable which represent the
number of ThreadContext registered in the System. Since this has to
match the size of the ThreadContext vector, this patch removes the
manually cached size. This was usually used as a for-loop index, whereas
we want to enforce the use of range-based loops whenever possible.

Change-Id: I1ba317c0393bcc9c1aeebbb1fc22d7b2bc2cf90c
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/8062
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>

arm,sim: fix context switch stats dumps for ARM64/Linux

32bit and 64bit Linux have different arguments passed to the
__switch_to() function that gem5 hooks into in order to collect context
switch statistics. 64bit Linux provides the task_struct pointer to the
next task that will be switched to, which means we don't have to look
up the task_struct from thread_info as we do in 32bit ARM Linux.

This patch adds a second set of accessors to ThreadInfo to extract
details such as the pid, tgid, task name, etc., directly from a
task_struct. The existing accessors maintain their existing behavior by
first looking up the task_struct and then calling these new accessors.

A 64-bit variant of the DumpStatsPCEvent class is added that uses these
new accessors to get the task details for the context switch dumps
directly from the task_struct passed to __switch_to().

Change-Id: I63c4b3e1ad64446751a91f6340901d5180d7382d
Reviewed-on: https://gem5-review.googlesource.com/2640
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Pau Cabre <pau.cabre@metempsy.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

syscall_emul: [PATCH 15/22] add clone/execve for threading and multiprocess simulations

Modifies the clone system call and adds execve system call. Requires allowing
processes to steal thread contexts from other processes in the same system
object and the ability to detach pieces of process state (such as MemState)
to allow dynamic sharing.

syscall_emul: [patch 5/22] remove LiveProcess class and use Process instead

The EIOProcess class was removed recently and it was the only other class
which derived from Process. Since every Process invocation is also a
LiveProcess invocation, it makes sense to simplify the organization by
combining the fields from LiveProcess into Process.

syscall_emul: [patch 2/22] move SyscallDesc into its own .hh and .cc

The class was crammed into syscall_emul.hh which has tons of forward
declarations and template definitions. To clean it up a bit, moved the
class into separate files and commented the class with doxygen style
comments. Also, provided some encapsulation by adding some accessors and
a mutator.

The syscallreturn.hh file was renamed syscall_return.hh to make it consistent
with other similarly named files in the src/sim directory.

The DPRINTF_SYSCALL macro was moved into its own header file with the
include the Base and Verbose flags as well.

style: [patch 1/22] use /r/3648/ to reorganize includes

kern, arm: Dump dmesg on kernel panic/oops

Add helper functions to dump the guest kernel's dmesg buffer to a text
file in m5out. This functionality is split into two parts. First, a
dmesg dump function that can be used in other places:

void Linux::dumpDmesg(ThreadContext *, std::ostream &)

This function is used to implement two PCEvents: DmesgDumpEvent and
KernelPanic event. The only difference between the two is that the
latter produces a gem5 panic instead of a warning in addition to
dumping the kernel log.

Change-Id: I6d2af1d666ace57124089648ea906f6c787ac63c
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>

arm: Remove BreakPCEvent on guest kernel panic

The LinuxArmSystem class normally provides support for panicing gem5
if the simulated kernel panics. When this is turned off (default),
gem5 uses a BreakPCEvent to provide a debugger hook into the simulator
when the kernel crashes. This hook unconditionally kills gem5 with a
SIGTRAP unless gem5 is compiled in fast mode. This is undesirable
since the panic_on_panic param already provides similar functionality.

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

syscall_emul: remove mmapFlagTable

After all this it turns out we don't even use it.

syscall_emul: factor out flag tables into common file

The openFlagTable and mmapFlagTables for emulated Linux
platforms are basically identical, but are specified
repetitively for every platform. Use a common file
that gets included for each platform so that we only
have one copy, making them more consistent and simplifying
changes (like adding #ifdefs).

In the process, made some minor fixes that slipped through
due to previous inconsistencies, and added more #ifdefs
to try to fix building on alternative hosts.

base: add symbol support for dynamic libraries

Libraries are loaded into the process address space using the
mmap system call. Conveniently, this happens to be a good
time to update the process symbol table with the library's
incoming symbols so we handle the table update from within the
system call.

This works just like an application's normal symbols. The only
difference between a dynamic library and a main executable is
when the symbol table update occurs. The symbol table update for
an executable happens at program load time and is finished before
the process ever begins executing. Since dynamic linking happens
at runtime, the symbol loading happens after the library is
first loaded into the process address space. The library binary
is examined at this time for a symbol section and that section
is parsed for symbol types with specific bindings (global,
local, weak). Subsequently, these symbols are added to the table
and are available for use by gem5 for things like trace
generation.

Checkpointing should work just as it did previously. The address
space (and therefore the library) will be recorded and the symbol
table will be entirely recorded. (It's not possible to do anything
clever like checkpoint a program and then load the program back
with different libraries with LD_LIBRARY_PATH, because the
library becomes part of the address space after being loaded.)

syscall_emul: extend mmap system call to support file backed mmaps

For O3, which has a stat that counts reg reads, there is an additional
reg read per mmap() call since there's an arg we no longer ignore.
Otherwise, stats should not be affected.

syscall_emul: add many Linux kernel flags

syscall_emul: rename OpenFlagTransTable struct

The structure definition only had the open system call flag set in mind when
it was named, so we rename it here with the intention of using it to define
additional tables to translate flags for other system calls in the future.

base: Add support for changing output directories

This changeset adds support for changing the simulator output
directory. This can be useful when the simulation goes through several
stages (e.g., a warming phase, a simulation phase, and a verification
phase) since it allows the output from each stage to be located in a
different directory. Relocation is done by calling core.setOutputDir()
from Python or simout.setOutputDirectory() from C++.

This change affects several parts of the design of the gem5's output
subsystem. First, files returned by an OutputDirectory instance (e.g.,
simout) are of the type OutputStream instead of a std::ostream. This
allows us to do some more book keeping and control re-opening of files
when the output directory is changed. Second, new subdirectories are
OutputDirectory instances, which should be used to create files in
that sub-directory.

Signed-off-by: Andreas Sandberg <andreas@sandberg.pp.se>
[sascha.bischoff@arm.com: Rebased patches onto a newer gem5 version]
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>

syscall_emul: Implement clock_getres() system call

This patch implements the clock_getres() system call for arm and x86 in linux
SE mode.

style: fix missing spaces in control statements

Result of running 'hg m5style --skip-all --fix-control -a'.

style: remove trailing whitespace

Result of running 'hg m5style --skip-all --fix-white -a'.

cpu: Move invldPid constant from Request to BaseCPU

A more natural home for this constant.

arm: Implement some missing syscalls (SE mode)

Adding a few syscalls that were previously considered unimplemented.

syscall_emul: fix warn_once behavior

The current ignoreWarnOnceFunc doesn't really work as expected,
since it will only generate one warning total, for whichever
"warn-once" syscall is invoked first. This patch fixes that
behavior by keeping a "warned" flag in the SyscallDesc object,
allowing suitably flagged syscalls to warn exactly once per
syscall.

arm: Remove unnecessary boot uncachability

With the recent patches addressing how we deal with uncacheable
accesses there is no longer need for the work arounds put in place to
enforce certain sections of memory to be uncacheable during boot.

arch, base, dev, kern, sym: FreeBSD support

This adds support for FreeBSD/aarch64 FS and SE mode (basic set of syscalls only)

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

arm: Add unlinkat syscall implementation

added ARM aarch64 unlinkat syscall support, modeled on other <xxx>at syscalls.
This gets all of the cpu2006 int workloads passing in SE mode on aarch64.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

arm: Fixes based on UBSan and static analysis

Another churn to clean up undefined behaviour, mostly ARM, but some
parts also touching the generic part of the code base.

Most of the fixes are simply ensuring that proper intialisation. One
of the more subtle changes is the return type of the sign-extension,
which is changed to uint64_t. This is to avoid shifting negative
values (undefined behaviour) in the ISA code.

arm: Fix multi-system AArch64 boot w/caches.

Automatically extract cpu release address from DTB file.
Check SCTLR_EL1 to verify all caches are enabled.

sim: revert 6709bbcf564d
The identifier SYS_getdents is not available on Mac OS X. Therefore, its use
results in compilation failure. It seems there is no straight forward way to
implement the system call getdents using readdir() or similar C functions.
Hence the commit 6709bbcf564d is being rolled back.

sim: implement getdents/getdents64 in user mode

Has been tested only for alpha.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>

sim, arm: implement more of the at variety syscalls

Needed for new AArch64 binaries

arm: Enable umask syscall in SE mode

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

arm: Add support for ARMv8 (AArch64 & AArch32)

Note: AArch64 and AArch32 interworking is not supported. If you use an AArch64
kernel you are restricted to AArch64 user-mode binaries. This will be addressed
in a later patch.

Note: Virtualization is only supported in AArch32 mode. This will also be fixed
in a later patch.

Contributors:
Giacomo Gabrielli (TrustZone, LPAE, system-level AArch64, AArch64 NEON, validation)
Thomas Grocutt (AArch32 Virtualization, AArch64 FP, validation)
Mbou Eyole (AArch64 NEON, validation)
Ali Saidi (AArch64 Linux support, code integration, validation)
Edmund Grimley-Evans (AArch64 FP)
William Wang (AArch64 Linux support)
Rene De Jong (AArch64 Linux support, performance opt.)
Matt Horsnell (AArch64 MP, validation)
Matt Evans (device models, code integration, validation)
Chris Adeniyi-Jones (AArch64 syscall-emulation)
Prakash Ramrakhyani (validation)
Dam Sunwoo (validation)
Chander Sudanthi (validation)
Stephan Diestelhorst (validation)
Andreas Hansson (code integration, performance opt.)
Eric Van Hensbergen (performance opt.)
Gabe Black

arm: Accomodate function name changes in newer linux kernels

arm: Enable support for triggering a sim panic on kernel panics

Add the options 'panic_on_panic' and 'panic_on_oops' to the
LinuxArmSystem SimObject. When these option are enabled, the simulator
panics when the guest kernel panics or oopses. Enable panic on panic
and panic on oops in ARM-based test cases.

sim: Add helper functions that add PCEvents with custom arguments

This changeset adds support for forwarding arguments to the PC
event constructors to following methods:

addKernelFuncEvent
addFuncEvent

Additionally, this changeset adds the following helper method to the
System base class:

addFuncEventOrPanic - Hook a PCEvent to a symbol, panic on failure.

addKernelFuncEventOrPanic - Hook a PCEvent to a kernel symbol, panic
on failure.


System implementations have been updated to use the new functionality
where appropriate.

scons: Add warning for overloaded virtual functions

A derived function with a different signature than a base class
function will result in the base class function of the same name being
hidden. The parameter list and return type for the member function in
the derived class must match those of the member function in the base
class, otherwise the function in the derived class will hide the
function in the base class and no polymorphic behaviour will occur.

This patch addresses these warnings by ensuring a unique function name
to avoid (unintentionally) hiding any functions.

loader: add a flattened device tree blob (dtb) object

this adds a dtb_object so the loader can load in the dtb
file for linux/android ARM kernels.

arm: add access syscall for ARM SE mode

This patch adds the "access" syscall for ARM SE as required by some spec2006
benchmarks.

base: Encapsulate the underlying fields in AddrRange

This patch makes the start and end address private in a move to
prevent direct manipulation and matching of ranges based on these
fields. This is done so that a transition to ranges with interleaving
support is possible.

As a result of hiding the start and end, a number of member functions
are needed to perform the comparisons and manipulations that
previously took place directly on the members. An accessor function is
provided for the start address, and a function is added to test if an
address is within a range. As a result of the latter the != and ==
operator is also removed in favour of the member function. A member
function that returns a string representation is also created to allow
debug printing.

In general, this patch does not add any functionality, but it does
take us closer to a situation where interleaving (and more cleverness)
can be added under the bonnet without exposing it to the user. More on
that in a later patch.

ARM: dump stats and process info on context switches

This patch enables dumping statistics and Linux process information on
context switch boundaries (__switch_to() calls) that are used for
Streamline integration (a graphical statistics viewer from ARM).

Fix: Address a few minor issues identified by cppcheck

This patch addresses a number of smaller issues identified by the code
inspection utility cppcheck. There are a number of identified leaks in
the arm/linux/system.cc (although the function only get's called once
so it is not a major problem), a few deletes in dev/x86/i8042.cc that
were not array deletes, and sprintfs where the character array had one
element less than needed. In the IIC tags there was a function
allocating an array of longs which is in fact never used.

ARM: added support for flattened device tree blobs

Newer Linux kernels require DTB (device tree blobs) to specify platform
configurations. The input DTB filename can be specified through gem5 parameters
in LinuxArmSystem.

syscall emulation: Enabled getrlimit and getrusage for x86.
Added/moved rlimit constants to base linux header file.

This patch is a revised version of Vince Weaver's earlier patch.

syscall emulation: Clean up ioctl handling, and implement for x86.

Enable different whitelists for different OS/arch combinations,
since some use the generic Linux definitions only, and others
use definitions inherited from earlier Unix flavors on those
architectures.

Also update x86 function pointers so ioctl is no longer
unimplemented on that platform.

This patch is a revised version of Vince Weaver's earlier patch.

ARM: Update version of linux we claim to be to 3.0.0.

Static binaries generated with new versions of libc complain that the kernel
is too old otherwise.

ARM: guard masked symbol tables by default

Symbol tables masked with the loadAddrMask create redundant entries
that could conflict with kernel function events that rely on the
original addresses. This patch guards the creation of those masked
symbol tables by default, with an option to enable them when needed
(for early-stage kernel debugging, etc.)

MEM: Enable multiple distributed generalized memories

This patch removes the assumption on having on single instance of
PhysicalMemory, and enables a distributed memory where the individual
memories in the system are each responsible for a single contiguous
address range.

All memories inherit from an AbstractMemory that encompasses the basic
behaviuor of a random access memory, and provides untimed access
methods. What was previously called PhysicalMemory is now
SimpleMemory, and a subclass of AbstractMemory. All future types of
memory controllers should inherit from AbstractMemory.

To enable e.g. the atomic CPU and RubyPort to access the now
distributed memory, the system has a wrapper class, called
PhysicalMemory that is aware of all the memories in the system and
their associated address ranges. This class thus acts as an
infinitely-fast bus and performs address decoding for these "shortcut"
accesses. Each memory can specify that it should not be part of the
global address map (used e.g. by the functional memories by some
testers). Moreover, each memory can be configured to be reported to
the OS configuration table, useful for populating ATAG structures, and
any potential ACPI tables.

Checkpointing support currently assumes that all memories have the
same size and organisation when creating and resuming from the
checkpoint. A future patch will enable a more flexible
re-organisation.

gcc: Clean-up of non-C++0x compliant code, first steps

This patch cleans up a number of minor issues aiming to get closer to
compliance with the C++0x standard as interpreted by gcc and clang
(compile with std=c++0x and -pedantic-errors). In particular, the
patch cleans up enums where the last item was succeded by a comma,
namespaces closed by a curcly brace followed by a semi-colon, and the
use of the GNU-extension typeof (replaced by templated functions). It
does not address variable-length arrays, zero-size arrays, anonymous
structs, range expressions in switch statements, and the use of long
long. The generated CPU code also has a large number of issues that
remain to be fixed, mainly related to overflows in implicit constant
conversion (due to shifts).

System: Move code in initState() back into constructor whenever possible.

The change to port proxies recently moved code out of the constructor into
initState(). This is needed for code that loads data into memory, however
for code that setups symbol tables, kernel based events, etc this is the wrong
thing to do as that code is only called when a checkpoint isn't being restored
from.

ARM: Fix valgrind reported error on O3 that was causing minor stats changes.

ARM: Add support for Versatile Express extended memory map

Also clean up how we create boot loader memory a bit.

MEM: Make port proxies use references rather than pointers

This patch is adding a clearer design intent to all objects that would
not be complete without a port proxy by making the proxies members
rathen than dynamically allocated. In essence, if NULL would not be a
valid value for the proxy, then we avoid using a pointer to make this
clear.

The same approach is used for the methods using these proxies, such as
loadSections, that now use references rather than pointers to better
reflect the fact that NULL would not be an acceptable value (in fact
the code would break and that is how this patch started out).

Overall the concept of "using a reference to express unconditional
composition where a NULL pointer is never valid" could be done on a
much broader scale throughout the code base, but for now it is only
done in the locations affected by the proxies.

MEM: Add port proxies instead of non-structural ports

Port proxies are used to replace non-structural ports, and thus enable
all ports in the system to correspond to a structural entity. This has
the advantage of accessing memory through the normal memory subsystem
and thus allowing any constellation of distributed memories, address
maps, etc. Most accesses are done through the "system port" that is
used for loading binaries, debugging etc. For the entities that belong
to the CPU, e.g. threads and thread contexts, they wrap the CPU data
port in a port proxy.

The following replacements are made:
FunctionalPort > PortProxy
TranslatingPort > SETranslatingPortProxy
VirtualPort > FSTranslatingPortProxy

SE: move page allocation from PageTable to Process

PageTable supported an allocate() call that called back
through the Process to allocate memory, but did not have
a method to map addresses without allocating new pages.
It makes more sense for Process to do the allocation, so
this method was renamed allocateMem() and moved to Process,
and uses a new map() call on PageTable.

The remaining uses of the process pointer in PageTable
were only to get the name and the PID, so by passing these
in directly in the constructor, we can make PageTable
completely independent of Process.

syscall_emul: implement MAP_FIXED option to mmap()

ARM: Mark some variables uncacheable until boot all CPUs are enabled.

There are a set of locations is the linux kernel that are managed via
cache maintence instructions until all processors enable their MMUs & TLBs.
Writes to these locations are manually flushed from the cache to main
memory when the occur so that cores operating without their MMU enabled
and only issuing uncached accesses can receive the correct data. Unfortuantely,
gem5 doesn't support any kind of software directed maintence of the cache.
Until such time as that support exists this patch marks the specific cache blocks
that need to be coherent as non-cacheable until all CPUs enable their MMU and
thus allows gem5 to boot MP systems with caches enabled (a requirement for
booting an O3 cpu and thus an O3 CPU regression).

ARM: Add support for loading the a bootloader and configuring parameters for it

fix some build problems from prior changesets

includes: sort all includes

ARM: Fix checkpoint restoration in ARM_SE.

ARM: Get rid of some comments/todos that no longer apply.

ARM: Add minimal ARM_SE support for m5threads.

Updated some of the assembly code sequences to use armv7 instructions and
coprocessor 15 for storing the TLS pointer.

ARM: Detect and skip udelay() functions in linux kernel.

This change speeds up booting, especially in MP cases, by not executing
udelay() on the core but instead skipping ahead tha amount of time that is being
delayed.

Style: Replace some tabs with spaces.

ARM: Add checkpointing support

sim: Use forward declarations for ports.

Virtual ports need TLB data which means anything touching a file in the arch
directory rebuilds any file that includes system.hh which in everything.

ISA,CPU,etc: Create an ISA defined PC type that abstracts out ISA behaviors.



This change is a low level and pervasive reorganization of how PCs are managed
in M5. Back when Alpha was the only ISA, there were only 2 PCs to worry about,
the PC and the NPC, and the lsb of the PC signaled whether or not you were in
PAL mode. As other ISAs were added, we had to add an NNPC, micro PC and next
micropc, x86 and ARM introduced variable length instruction sets, and ARM
started to keep track of mode bits in the PC. Each CPU model handled PCs in
its own custom way that needed to be updated individually to handle the new
dimensions of variability, or, in the case of ARMs mode-bit-in-the-pc hack,
the complexity could be hidden in the ISA at the ISA implementation's expense.
Areas like the branch predictor hadn't been updated to handle branch delay
slots or micropcs, and it turns out that had introduced a significant (10s of
percent) performance bug in SPARC and to a lesser extend MIPS. Rather than
perpetuate the problem by reworking O3 again to handle the PC features needed
by x86, this change was introduced to rework PC handling in a more modular,
transparent, and hopefully efficient way.


PC type:

Rather than having the superset of all possible elements of PC state declared
in each of the CPU models, each ISA defines its own PCState type which has
exactly the elements it needs. A cross product of canned PCState classes are
defined in the new "generic" ISA directory for ISAs with/without delay slots
and microcode. These are either typedef-ed or subclassed by each ISA. To read
or write this structure through a *Context, you use the new pcState() accessor
which reads or writes depending on whether it has an argument. If you just
want the address of the current or next instruction or the current micro PC,
you can get those through read-only accessors on either the PCState type or
the *Contexts. These are instAddr(), nextInstAddr(), and microPC(). Note the
move away from readPC. That name is ambiguous since it's not clear whether or
not it should be the actual address to fetch from, or if it should have extra
bits in it like the PAL mode bit. Each class is free to define its own
functions to get at whatever values it needs however it needs to to be used in
ISA specific code. Eventually Alpha's PAL mode bit could be moved out of the
PC and into a separate field like ARM.

These types can be reset to a particular pc (where npc = pc +
sizeof(MachInst), nnpc = npc + sizeof(MachInst), upc = 0, nupc = 1 as
appropriate), printed, serialized, and compared. There is a branching()
function which encapsulates code in the CPU models that checked if an
instruction branched or not. Exactly what that means in the context of branch
delay slots which can skip an instruction when not taken is ambiguous, and
ideally this function and its uses can be eliminated. PCStates also generally
know how to advance themselves in various ways depending on if they point at
an instruction, a microop, or the last microop of a macroop. More on that
later.

Ideally, accessing all the PCs at once when setting them will improve
performance of M5 even though more data needs to be moved around. This is
because often all the PCs need to be manipulated together, and by getting them
all at once you avoid multiple function calls. Also, the PCs of a particular
thread will have spatial locality in the cache. Previously they were grouped
by element in arrays which spread out accesses.


Advancing the PC:

The PCs were previously managed entirely by the CPU which had to know about PC
semantics, try to figure out which dimension to increment the PC in, what to
set NPC/NNPC, etc. These decisions are best left to the ISA in conjunction
with the PC type itself. Because most of the information about how to
increment the PC (mainly what type of instruction it refers to) is contained
in the instruction object, a new advancePC virtual function was added to the
StaticInst class. Subclasses provide an implementation that moves around the
right element of the PC with a minimal amount of decision making. In ISAs like
Alpha, the instructions always simply assign NPC to PC without having to worry
about micropcs, nnpcs, etc. The added cost of a virtual function call should
be outweighed by not having to figure out as much about what to do with the
PCs and mucking around with the extra elements.

One drawback of making the StaticInsts advance the PC is that you have to
actually have one to advance the PC. This would, superficially, seem to
require decoding an instruction before fetch could advance. This is, as far as
I can tell, realistic. fetch would advance through memory addresses, not PCs,
perhaps predicting new memory addresses using existing ones. More
sophisticated decisions about control flow would be made later on, after the
instruction was decoded, and handed back to fetch. If branching needs to
happen, some amount of decoding needs to happen to see that it's a branch,
what the target is, etc. This could get a little more complicated if that gets
done by the predecoder, but I'm choosing to ignore that for now.


Variable length instructions:

To handle variable length instructions in x86 and ARM, the predecoder now
takes in the current PC by reference to the getExtMachInst function. It can
modify the PC however it needs to (by setting NPC to be the PC + instruction
length, for instance). This could be improved since the CPU doesn't know if
the PC was modified and always has to write it back.


ISA parser:

To support the new API, all PC related operand types were removed from the
parser and replaced with a PCState type. There are two warts on this
implementation. First, as with all the other operand types, the PCState still
has to have a valid operand type even though it doesn't use it. Second, using
syntax like PCS.npc(target) doesn't work for two reasons, this looks like the
syntax for operand type overriding, and the parser can't figure out if you're
reading or writing. Instructions that use the PCS operand (which I've
consistently called it) need to first read it into a local variable,
manipulate it, and then write it back out.


Return address stack:

The return address stack needed a little extra help because, in the presence
of branch delay slots, it has to merge together elements of the return PC and
the call PC. To handle that, a buildRetPC utility function was added. There
are basically only two versions in all the ISAs, but it didn't seem short
enough to put into the generic ISA directory. Also, the branch predictor code
in O3 and InOrder were adjusted so that they always store the PC of the actual
call instruction in the RAS, not the next PC. If the call instruction is a
microop, the next PC refers to the next microop in the same macroop which is
probably not desirable. The buildRetPC function advances the PC intelligently
to the next macroop (in an ISA specific way) so that that case works.


Change in stats:

There were no change in stats except in MIPS and SPARC in the O3 model. MIPS
runs in about 9% fewer ticks. SPARC runs with 30%-50% fewer ticks, which could
likely be improved further by setting call/return instruction flags and taking
advantage of the RAS.


TODO:

Add != operators to the PCState classes, defined trivially to be !(a==b).
Smooth out places where PCs are split apart, passed around, and put back
together later. I think this might happen in SPARC's fault code. Add ISA
specific constructors that allow setting PC elements without calling a bunch
of accessors. Try to eliminate the need for the branching() function. Factor
out Alpha's PAL mode pc bit into a separate flag field, and eliminate places
where it's blindly masked out or tested in the PC.

ARM: Add system for ARM/Linux and bootstrapping

ARM: Fix SPEC2000 benchmarks in SE mode. With this patch all
Spec2k benchmarks seem to run with atomic or timing mode simple
CPUs. Fixed up some constants, handling of 64 bit arguments,
and marked a few more syscalls ignoreFunc.

ARM: fix sizes of structs for ARM Linux

ARM: Fixup native trace support and add some v7/recent stack code

ARM: Implement the getrusage syscall.

ARM: Allow ARM processes to start in Thumb mode.

Syscalls: Make system calls access arguments like a stack, not an array.

When accessing arguments for a syscall, the position of an argument depends on
the policies of the ISA, how much space preceding arguments took up, and the
"alignment" of the index for this particular argument into the number of
possible storate locations. This change adjusts getSyscallArg to take its
index parameter by reference instead of value and to adjust it to point to the
possible location of the next argument on the stack, basically just after the
current one. This way, the rules for the new argument can be applied locally
without knowing about other arguments since those have already been taken into
account implicitly.

All system calls have also been changed to reflect the new interface. In a
number of cases this made the implementation clearer since it encourages
arguments to be collected in one place in order and then used as necessary
later, as opposed to scattering them throughout the function or using them in
place in long expressions. It also discourages using getSyscallArg over and
over to retrieve the same value when a temporary would do the job.

syscall: Addition of an ioctl command code for Power.

Syscalls: Implement sysinfo() syscall.

ARM: Fix an instruction in the cmpxchg kernel provided routine.
The instruction was encoded as a load instead of the intended store.

ARM: Get rid of a stray line in the set_tls handler.

ARM: Ignore the "times" system call.

ARM: Fix an ioctl constant.

ARM: Update some syscall constants and delete others that are Alpha only.

ARM: Fix fstat/fstat64 structs to match EABI definitions.

ARM: Handle register indexed system calls.

ARM: Fix the "open" flag constants.

ARM: Hook in the mmap2 system call. Make ArmLinuxProcess handle 5,6 syscall params.

ARM: Add a memory_barrier function to the "comm page".
This function doesn't actually provide a memory barrier (I don't think they're
implemented) and instead just returns.

ARM: Add a cmpxchg implementation to the "comm page".
This implementation does what it's supposed to (I think), but it's not atomic
and doesn't have memory barriers like the kernel's version.

ARM: Implement TLS. This is not tested.

ARM: Make ArmLinuxProcess understand "ARM private" system calls.

ARM: Update the kernel version M5 reports to 2.6.16.19

Merge ARM into the head. ARM will compile but may not actually work.

arm: add ARM support to M5