arch-riscv: fix GDB register cache

Fixes the definition of the RISC-V GDB register cache. The latest
version, of RISC-V gdb, commit c3eb4078520dad8234ffd7fbf893ac0da23ad3c8,
appears to only accept the 32 integer registers + the PC in the 'g'
packet.

This functions with the Linux toolchain (riscv64-unknown-linux-gnu-*),
but works best with the Newlib toolchain (riscv64-unknown-elf-*).

Change-Id: Ie35ea89a45870fb634e6c68236261bde27c86e41
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20028
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-riscv: Update register file

This patch adds mcounteren, scounteren according to Risc-V
Privileged Architectures V1.10.

Change-Id: I6e138a50710bc0a1e9d9c38a11fc7fcc09ed500e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20128
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

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>

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>

riscv: Add an object file loader for linux.

Change-Id: I3accca91cc4e02fa8e3a1169590cbe6696cf05e2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18628
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>

arch-riscv: Implement MHARTID CSR

This patch implements the MHARTID CSR by intercepting attempts to access
it, similar to the way accesses to the performance counters are
intercepted, to return the thread's context ID.

Change-Id: Ie14a31036fbe0e49fb3347ac0c3c508d9427a10d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/16988
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-riscv,isa: Fix for compressed jump (c_j) imm

c_j(al) has a special format, called CJ.
The jump offset format is instbits[12:2] --> offset[11|4|9:8|10|6|7|3:1|5]
Currently in decoder.isa, c_j format is JOp, the imm and branchTarget are incorrect
In the execute section (decoder.isa:228), the imm fields is ignored and the offset is calculated correctlly.
As a result, we get decoder flush for each c_j instance
I've added CJOp format in compressed.isa, and use it in execute section.
In addition, c_j is mappped to jal zero, cj_imm, and actually is neither indirect control nor a function call
I fixed the flags accordently.
I'll fix all IsRet, IsCall and IsIndirectControl flags for rest of (c_)jal(r) in my next commit.
I ran coremark -O0 before my fix and I got 37.7% branch miss-rate, after the fix the branch miss-rate is <13%

Change-Id: I608d5894a78a1ebefe36f21e21aaea68b42bccfc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17808
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>

arch: Stop using TheISA within the ISAs.

We know for sure what the ISA is, so there's no need for the
indirection.

Change-Id: I73ff04c50890d40a4c7f40caeee746b68b846cb3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18488
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch, sim: Simplify the AuxVector type.

The AuxVector type has a bunch of accessors which just give access to
the underlying variables through references. We might as well just make
those members accessible directly.

Also, the AuxVector doesn't need to handle endianness flips itself. We
can tell the byteswap mechanism how to flip an AuxVector, and let it
handle that for us.

This gets rid of the entire .cc file which was complicated by trying
to both hide the ISA specific endianness translations, and instantiate
templated functions in a .cc.

Change-Id: I433cd61e73e0b067b6d628fba31be4a4ec1c4cf0
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18373
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

python: Don't assume SimObjects live in the global namespace

The importer in Python 3 doesn't like the way we import SimObjects
from the global namespace. Convert the existing SimObject declarations
to import from m5.objects. As a side-effect, this makes these files
consistent with configuration files.

Change-Id: I11153502b430822130722839e1fa767b82a027aa
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15981
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>

riscv: fix AMO, LR and SC instructions

(1) Atomic Memory Operation (AMO)

This patch changes how RISC-V AMO instructions are implemented. For each
AMO, instead of issuing a locking load and an unlocking store request to
downstream memory system, this patch issues a single memory request that
contains a corresponding AtomicOpFunctor to the memory system. Once the
memory system receives the request, the atomic operation is executed in
one single step.

This patch also changes how AMO instructions handle acquire and release
flags in AMOs (e.g., amoadd.aq and amoadd.rl). If an AMO is associated
with an acquire flag, a memory fence is inserted after the AMO completes
as a micro-op. If an AMO is associated with a release flag, another
memory fence is inserted before the AMO executes. If both flags are
specified, the AMO is broken down into a sequence of 3 micro-ops:
mem fence -> atomic RMW -> mem fence. This change makes this AMO
implementation comply to the release consistency model.

(2) Load-Reserved (LR) and Store-Conditional (SC)

Addresses locked by LR instructions are tracked in a stack data
structure. LR instruction pushes its target address to the stack, and SC
instruction pops the top address from the stack. As specified by RISC-V
ISA, a SC fails if its target address does not match with the most recent
LR.

Previously, there was a single stack for all hardware thread contexts.
A shared stack between thread contexts can lead to a infinite sequence
of failed SCs if LRs from other threads keep pushing new addresses to
this stack.

This patch gives each context its private stack to address the problem.

This patch also adds extra memory fence micro-ops to lr/sc to guarantee
a correct execution order of memory instructions with respect to release
consistency model.

Change-Id: I1e95900367c89dd866ba872a5203f63359ac51ae
Reviewed-on: https://gem5-review.googlesource.com/c/8189
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

riscv: fixed syscall return value

In case of failure, a syscall returns a negative value encoding the
error code. This patch makes the risc-v implementation returns the
encoded value instead of its absolute value upon a failure of a syscall.

Change-Id: I6032b0337fe1cff5b326dbc6bb3b87a415f03300
Reviewed-on: https://gem5-review.googlesource.com/c/9627
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

riscv: ignore nanosleep syscall

Change-Id: I564a09564da668a5db3e75f15b33efaca363d71a
Reviewed-on: https://gem5-review.googlesource.com/c/9624
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: initialize RISC-V's thread pointer register in clone syscall

This patch initializes thread pointer register to Thread Local Storage
(TLS)'s pointer given to a clone system call.

Change-Id: I03e2cf4763e6a0ed31f357772a513a05e1e3461b
Reviewed-on: https://gem5-review.googlesource.com/c/9622
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>

arch-riscv: Enable support for riscv 32-bit in SE mode.

This patch splits up the riscv SE mode support for 32 and 64-bit.
A future patch will add support for decoding rv32 instructions.

Change-Id: Ia79ae19f753caf94dc7e5830a6630efb94b419d7
Signed-off-by: Austin Harris <austinharris@utexas.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/15355
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>

riscv: remove NonSpeculative flag from fence inst

Fence instruction origially had two flags NonSpeculative and
MemBarrier. In O3 model, MemBarrier instructions are inserted
into the instruction queue by the InstructionQueue::insertBarrier (at
src/cpu/o3/iew_impl.hh:1083). Barrier instructions are implicitly
assumed to be non-speculative.

Adding NonSpeculative flag to fence instruction makes it inserted into
the instruction queue twice (at src/cpu/o3/iew_impl.hh:1083 and :1111).
This can lead to a deadlock if both pointers to the instruction are not
cleared from the queue when the instruction retires.

This patch removes NonSpeculative flag from the fence inst.

Change-Id: I26573d12a0b52f43b73c0e51158286dc98d05ea4
Reviewed-on: https://gem5-review.googlesource.com/c/8183
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Initialize interrupt mask

This patch initializes RISCV interrupt mask to 0.

Change-Id: I56289d9f3f319e239e305befea006a0ad4d86b75
Reviewed-on: https://gem5-review.googlesource.com/c/16162
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

misc: added missing override specifier

Added missing specifier for various virtual functions.

Change-Id: I4783e92d78789a9ae182fad79aadceafb00b2458
Reviewed-on: https://gem5-review.googlesource.com/c/16103
Reviewed-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

riscv: Get rid of ISA specific register types in Interrupts.

Change-Id: I5542649c6af27a286f276a289b86c40dd7e32abc
Signed-off-by: Austin Harris <austinharris@utexas.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/16122
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

cpu, arch: Replace the CCReg type with RegVal.

Most architectures weren't using the CCReg type, and in x86 and arm
it was already a uint64_t.

Change-Id: I0b3d5e690e6b31db6f2627f449c89bde0f6750a6
Reviewed-on: https://gem5-review.googlesource.com/c/14515
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

riscv: Get rid of some ISA specific register types.

Change-Id: Ie812cf1d42536094273ba2ec731c16cca38db100
Reviewed-on: https://gem5-review.googlesource.com/c/14466
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>

arch: cpu: Rename *FloatRegBits* to *FloatReg*.

Now that there's no plain FloatReg, there's no reason to distinguish
FloatRegBits with a special suffix since it's the only way to read or
write FP registers.

Change-Id: I3a60168c1d4302aed55223ea8e37b421f21efded
Reviewed-on: https://gem5-review.googlesource.com/c/14460
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch,cpu: Add vector predicate registers

Latest-gen. vector/SIMD extensions, including the Arm Scalable Vector
Extension (SVE), introduce the notion of a predicate register file.
This changeset adds this feature across architectures and CPU models.

Change-Id: Iebcadbad89c0a582ff8b1b70de353305db603946
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13715
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

base: arch: Get rid of the now unused FloatRegVal type.

This type is no longer used since FP registers are accessed as integer
bit patterns.

Change-Id: I1070f9443d6247165fd64c6bc041811c28287e9f
Reviewed-on: https://gem5-review.googlesource.com/c/14459
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch: cpu: Stop passing around misc registers by reference.

These values are all basic integers (specifically uint64_t now), and
so passing them by const & is actually less efficient since there's a
extra level of indirection and an extra value, and the same sized value
(a 64 bit pointer vs. a 64 bit int) is being passed around.

Change-Id: Ie9956b8dc4c225068ab1afaba233ec2b42b76da3
Reviewed-on: https://gem5-review.googlesource.com/c/13626
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.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>

arch: Make the ISA register types aliases for the global types.

The ISA specific types can thus be phased out.

Change-Id: I8ea531a099fad140a4ec9c91cd972fe044111d60
Reviewed-on: https://gem5-review.googlesource.com/c/13623
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: Add interrupt handling

Implement the Interrupts SimObject for RISC-V. This basically just
handles setting and getting the values of the interrupt-pending and
interrupt-enable CSRs according to the privileged ISA reference chapter
3.1.14. Note that it does NOT implement the PLIC as defined in chapter
7, as that is used for handling external interrupts which are defined
based on peripherals that are available.

Change-Id: Ia1321430f870ff5a3950217266fde0511332485b
Reviewed-on: https://gem5-review.googlesource.com/c/14377
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: Fix reset function and style

In addition to fixing some style issues with resetting, this patch fixes
what happens on reset. The RISC-V privileged ISA reference manual says
that,
on reset:
1. Privilege mode is set to M
2. mstatus.mie <- 0; mstatus.mprv <- 0
3. PC <- reset vector
4. mcause <- reset cause (0 if there is no distinguishing causes)
5. Everything else is undefined
Because of 5, everything else will be left alone

Change-Id: I81bdf7a88b08874e3c3d5fc6c7f3ca2d796496b8
Reviewed-on: https://gem5-review.googlesource.com/c/14376
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.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>

syscall_emul: expand AuxVector class

The AuxVector class is responsible for holding Process data.
The data that it holds is normally setup by an OS kernel in
the process address space. The purpose behind doing this is
to pass in information that the process will need for various
reasons. (Check out the enum in the header file for an idea of
what the AuxVector holds.)

The AuxVector struct was changed into a class and encapsulation
methods were added to protect access to the member variables.

The host ISA may have a different endianness than the simulated
ISA. Since data is passed between the process address space and
the simulator for auxiliary vectors, we need to worry about
maintaining endianness for the right context.

Change-Id: I32c5ac4b679559886e1efeb4b5483b92dfc94af9
Reviewed-on: https://gem5-review.googlesource.com/12109
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

arch-riscv: Add xret instructions

This patch adds the uret, sret, and mret instructions for use with
returning from user-, supervisor-, and machine-level code, respectively.
These instructions read the STATUS register to determine the previous
privilege level and modify it to re-enable interrupts at the old
privilege level. These instructions can only be executed at the
corresponding privilege level or higher.

Change-Id: I6125c31cb2fdcc3f83eca86910519e81ffbbbfc9
Reviewed-on: https://gem5-review.googlesource.com/11136
Maintainer: Alec Roelke <alec.roelke@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Robert Scheffel <robert.scheffel1@tu-dresden.de>

arch-riscv: Add support for trap value register

RISC-V has a set of CSRs that contain information about a trap that was
taken into each privilegel level, such as illegal instruction bytes or
faulting address. This patch adds that register, modifies existing
faults to make use of it, and adds a new fault for future use with
handling page faults and bad addresses.

Change-Id: I3004bd7b907e7dc75e5f1a8452a1d74796a7a551
Reviewed-on: https://gem5-review.googlesource.com/11135
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>

arch-riscv: Add support for fault handling

This patch adds support for handling RISC-V faults, including tracking
current and previous execution privilege, correctly switching to
the privilege mode specified by CSRs, and setting/storing the PC. It
also includes changes introduced by patch #9821, which disables
interrupts during handling of a fault.

Change-Id: Ie9c0f29719620c20783540d3bdb2db44f6114fc9
Reviewed-on: https://gem5-review.googlesource.com/9161
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: enable rudimentary fs simulation

These changes enable a simple binary to be simulated in full system mode.
Additionally, a new fault was implemented.
It is executed once the CPU is initialized.
This fault clears all interrupts and sets the pc to a reset vector.

Change-Id: I50cfac91a61ba39a6ef3d38caca8794073887c88
Reviewed-on: https://gem5-review.googlesource.com/9061
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: Fix the srlw and srliw instructions.

Change-Id: I14ccb0655819887db2306fee1188e1c83a991743
Signed-off-by: Austin Harris <austinharris@utexas.edu>
Reviewed-on: https://gem5-review.googlesource.com/11669
Reviewed-by: Alec Roelke <alec.roelke@gmail.com>
Maintainer: Alec Roelke <alec.roelke@gmail.com>

misc: Using smart pointers for memory Requests

This patch is changing the underlying type for RequestPtr from Request*
to shared_ptr<Request>. Having memory requests being managed by smart
pointers will simplify the code; it will also prevent memory leakage and
dangling pointers.

Change-Id: I7749af38a11ac8eb4d53d8df1252951e0890fde3
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10996
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

misc: Substitute pointer to Request with aliased RequestPtr

Every usage of Request* in the code has been replaced with the
RequestPtr alias. This is a preparing patch for when RequestPtr will be
the typdefed to a smart pointer to Request rather then a raw pointer to
Request.

Change-Id: I73cbaf2d96ea9313a590cdc731a25662950cd51a
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10995
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

arch-riscv: Update CSR implementations

This patch updates the CSRs to match the RISC-V privileged specification
version 1.10. As interrupts, faults, and privilege levels are not yet
supported, there are no meaninful side effects that are implemented.
Performance counters are also not yet implemented, as they do not have
specifications. Currently they act as cycle counters.

Note that this implementation trusts software to use the registers
properly. Access protection, readability, and writeability of registers
based on privilege will come in a future patch.

Change-Id: I1de89bdbe369b5027911b2e6bc0425d3acaa708a
Reviewed-on: https://gem5-review.googlesource.com/7441
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch: cpu: Make the ExtMachInst type a template argument in InstMap.

This doesn't completely hide the ISA specific ExtMachInst type inside
the ISAs since it still gets applied in arch/generic, but it at least
pulls it into the arch directory.

Change-Id: Ic2188d59696530d7ecafdff0785d71867182701d
Reviewed-on: https://gem5-review.googlesource.com/9403
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch: Fix all override related warnings.

Clang has started(?) reporting override related warnings, something gcc
apparently did before, but was disabled in the SConstruct. Rather than
disable the warnings in for clang as well, this change fixes the
warnings. A future change will re-enable the warnings for gcc.

Change-Id: I3cc79e45749b2ae0f9bebb1acadc56a3d3a942da
Reviewed-on: https://gem5-review.googlesource.com/9343
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch: Add a virtual asBytes function to the StaticInst class.

This function takes a pointer to a buffer and the current size of the
buffer as a pass by reference argument. If the size of the buffer is
sufficient, the function stores a binary representation of itself
(generally the ISA defined instruction encoding) in the buffer, and
sets the size argument to how much space it used. This could be used
by ISAs which have two instruction sizes (ARM and thumb, for example).
If the buffer size isn't sufficient, then the size parameter should be
set to what size is required, and then the function should return
without modifying the buffer.

The buffer itself should be aligned to the same standard as memory
returned by new, specifically "The pointer returned shall be suitably
aligned so that it can be converted to a pointer of any complete object
type and then used to access the object or array in the storage
allocated...". This will avoid having to memcpy buffers to avoid
unaligned accesses.

To standardize the representation of the data, it should be stored in
the buffer as little endian. Since most hosts (including ARM and x86
hosts) will be little endian, this will almost always be a no-op.

Change-Id: I2f31aa0b4f9c0126b44f47a881c2901243279bd6
Reviewed-on: https://gem5-review.googlesource.com/7562
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

riscv: throw IllegalInstFault when decoding invalid instructions

If an instruction is invalid, some assertions may in the decoder may
fail the entire simulation. Instead, we want to raise an
IllegalInstFault instead of failing immediately in the decoder if the
invalid instruction is being speculatively executed.

Change-Id: I5cb72ba06f07f173922f86897ddfdf677e8c702f
Reviewed-on: https://gem5-review.googlesource.com/9261
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Monir Zaman <monir.zaman.m@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: Fix compressed branch op offset

There is a bug in RISC-V's compressed branch instructions where the
offsets are not stored in ImmOp's immediate field, causing incorrect
branchTarget() return values. This patch adds a new compressed branch
op format, CBOp, which correctly stores the offset.

Change-Id: Iac6e9b091d63f3dce4717ee5a9ec31a7cbd6c377
Reviewed-on: https://gem5-review.googlesource.com/8441
Reviewed-by: Tuan Ta <qtt2@cornell.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

riscv: Add overrides to various StaticInst methods.

This makes riscv compile with the version of clang(++) I have on my
workstation.

Change-Id: I0478616810fbc8a715fd61323b7e0f73676c8328
Reviewed-on: https://gem5-review.googlesource.com/7643
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch, mem: Make the page table lookup function return a pointer.

This avoids having a copy in the lookup function itself, and the
declaration of a lot of temporary TLB entry pointers in callers. The
gpu TLB seems to have had the most dependence on the original signature
of the lookup function, partially because it was relying on a somewhat
unsafe copy to a TLB entry using a base class pointer type.

Change-Id: I8b1cf494468163deee000002d243541657faf57f
Reviewed-on: https://gem5-review.googlesource.com/7343
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

sim, arch, base: Refactor the base remote GDB class.

Fold the GDBListener class into the main BaseRemoteGDB class, move
around a bunch of functions, convert a lot of internal functions to
be private, move some functions into the .cc, make some functions
non-virtual which didn't really need to be overridden.

Change-Id: Id0832b730b0fdfb2eababa5067e72c66de1c147d
Reviewed-on: https://gem5-review.googlesource.com/7422
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch, mem, sim: Consolidate and rename the SE mode page table classes.

Now that Nothing inherits from PageTableBase directly, it can be
merged into FuncPageTable. This change also takes the opportunity to
rename the combined class to EmulationPageTable which lets you know
that it's specifically for SE mode.

Also remove the page table entry cache since it doesn't seem to
actually improve performance. The TLBs likely absorb the majority of
the locality, essentially acting like a cache like they would in real
hardware.

Change-Id: If1bcb91aed08686603bf7bee37298c0eee826e13
Reviewed-on: https://gem5-review.googlesource.com/7342
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch-riscv: Fix floating-poing op classes

This patch applies correct miscellaneous or multiply-accumulate op
classes to floating point instructions which had previously been
incorrectly classed as add or multiply instructions.

Change-Id: I959dd8d3152aa341e0f060b003ce1da8c4d688fb
Reviewed-on: https://gem5-review.googlesource.com/6521
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Fix floating-point conversion bugs

Using the fetestexcept function to check for specific types of floating
point exceptions is unreliable for some kinds of
floating-point-to-integer conversion operations. RISC-V code used to
make use of them to check for some exceptional cases like overflow and
underflow, which caused incorrect output when compiler optimization is
turned on. This patch changes the use of fetestexcept to explicit checks
for those exceptional cases.

Change-Id: Id983906ea0664dc246e115a9e470d9ab7733bde1
Reviewed-on: https://gem5-review.googlesource.com/6402
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch: Fix a fatal_if in most of the arch's process classes.

When switching an assert to a fatal while addressing recent review
feedback, I forgot to reverse the polarity of the condition, making
the fatal fire in exactly the opposite of the conditions it was meant
to.

Change-Id: Icf49864ef449052bbb0d427dca786006166575c4
Reviewed-on: https://gem5-review.googlesource.com/7381
Reviewed-by: Matthias Jung <jungma@eit.uni-kl.de>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: Don't crash when printing unknown CSRs

This patch fixes a potential crash if an unnamed CSR is accessed and
debug flags are enabled that print disassembly. Unknown CSRs will be
identified as "??" followed by the address that was used.

Change-Id: If5ac57f1422bd59c72a1a06206fa9d9dc05d21ef
Reviewed-on: https://gem5-review.googlesource.com/7321
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch,mem: Remove the default value for page size.

This breaks one more architecture dependence outside of the ISAs.

Change-Id: I071f9ed73aef78e1cd1752247c183e30854b2d28
Reviewed-on: https://gem5-review.googlesource.com/6982
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Alexandru Duțu <alexandru.dutu@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>

arch,mem: Move page table construction into the arch classes.

This gets rid of an awkward NoArchPageTable class, and also gives the
arch a place to inject ISA specific parameters (specifically page size)
without having to have TheISA:: in the generic version of these types.

Change-Id: I1412f303460d5c43dafdb9b3cd07af81c908a441
Reviewed-on: https://gem5-review.googlesource.com/6981
Reviewed-by: Alexandru Duțu <alexandru.dutu@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch-riscv: Make use of ImmOp's polymorphism

This patch makes use of ImmOp's polymorphism to remove unnecessary
casting from the implementations of arithmetic instructions with
immediate operands and to remove the CUIOp format by combining it with
the CIOp format (compressed arithmetic instructions with immediate
operands). Interestingly, RISC-V specifies that instructions with
unsigned immediate operands still need to sign-extend the immediates
from 12 (or 20) bits to 64 bits, so that is left alone.

Change-Id: If20d70c1e90f379b9ed8a4155b2b9222b6defe16
Reviewed-on: https://gem5-review.googlesource.com/6401
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Tuan Ta <qtt2@cornell.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

alpha,arm,mips,power,riscv,sparc,x86,cpu: Get rid of ISA_HAS_DELAY_SLOT.

This constant is, first, a #define, and second only used in one place.

In that one place, it appears that the code it guards is no longer
necessary in general. It was originally written to avoid refetching a
block of data that you're still in, even if you've moved slightly
farther in it because you're skipping the next instruction due to an
annulled branch delay slot. In reality however, in SPARC, the one ISA
I'm aware of which has this sort of branching behavior, the PC state
object will correctly determine that no branch is happening in these
cases. Code lower down in the loop will then recompute where fetching
should continue based on the next PC, automatically skipping the
annulled branch slot without misinterpretting the gap as a branch.

This change therefore also removes this block of code.

Change-Id: I820ebc9df10aeb4fcb69c12f6a784e9ec616743c
Reviewed-on: https://gem5-review.googlesource.com/6821
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-riscv: Ignore sched_yield syscall in SE mode

Change-Id: I14f22c06eb8fdbe063980b4cd0a49387b9113a97
Reviewed-on: https://gem5-review.googlesource.com/6961
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Ignore set_robust_list and get_robust_list syscalls

Change-Id: I5a4744e5aed07337144af9f07978b83405b6695b
Reviewed-on: https://gem5-review.googlesource.com/6902
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Add an implementation of set_tid_address syscall in RISCV

Change-Id: Ida29ea6f6a9c3efe00aaebbfcb6b537fc62f6d06
Reviewed-on: https://gem5-review.googlesource.com/6901
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Correct syscall argument reg count

As per the discussion in patch #6904 and the Linux 4.15 kernel code for
RISC-V, RISC-V has 7 system call argument registers, x10 through x16 (a0
through a6), with x17 (a7) being used for the system call number.

Change-Id: I0080eca78ffa844b322bb2cff2a51ab2815f3809
Reviewed-on: https://gem5-review.googlesource.com/7081
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Tuan Ta <qtt2@cornell.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Remove "magic" syscall number constant

getSyscallArg() in RISC-V has an explicit check to make sure that the
register index is within the bounds of the system call register indices
vector. This patch fixes it so that it uses SyscallArgumentRegs.size()
rather than a "magic" constant that has to be updated every time
SyscallArgumentRegs is changed.

Change-Id: I2935d811177dc8028cb3df64b250ba997bc970d8
Reviewed-on: https://gem5-review.googlesource.com/7061
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

alpha,arm,mips,power,riscv,sparc,x86: Get rid of TheISA::NoopMachInst.

It's no longer used.

Change-Id: I4a71bcb214f1bb186b92ef50841eca635e6701c5
Reviewed-on: https://gem5-review.googlesource.com/6826
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

riscv,x86: Stop using the arch Nop machine instruction unnecessarily.

That particular ExtMachInst is a convenient placeholder, but a value
of 0 in RISCV or a static uninitialized ExtMachInst (which will
therefore be all zeroes) on x86 works just as well, and removes the
need for an ISA specific constant.

Also, the idea of a universal Nop doesn't always make sense since it
could be that what, exactly, doesn't do anything depends on context
which would be lost on a constant value of an ExtMachInst. For
instance, the value of an ExtMachInst that makes sense might depend on
what mode the CPU was in, etc.

Change-Id: I1f1a43a5c607a667e11b79bcf6e059e4f7141b3f
Reviewed-on: https://gem5-review.googlesource.com/6825
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Gabe Black <gabeblack@google.com>

arch,cpu: "virtualize" the TLB interface.

CPUs have historically instantiated the architecture specific version
of the TLBs to avoid a virtual function call, making them a little bit
more dependent on what the current ISA is. Some simple performance
measurement, the x86 twolf regression on the atomic CPU, shows that
there isn't actually any performance benefit, and if anything the
simulator goes slightly faster (although still within margin of error)
when the TLB functions are virtual.

This change switches everything outside of the architectures themselves
to use the generic BaseTLB type, and then inside the ISA for them to
cast that to their architecture specific type to call into architecture
specific interfaces.

The ARM TLB needed the most adjustment since it was using non-standard
translation function signatures. Specifically, they all took an extra
"type" parameter which defaulted to normal, and translateTiming
returned a Fault. translateTiming actually doesn't need to return a
Fault because everywhere that consumed it just stored it into a
structure which it then deleted(?), and the fault is stored in the
Translation object when the translation is done.

A little more work is needed to fully obviate the arch/tlb.hh header,
so the TheISA::TLB type is still visible outside of the ISAs.
Specifically, the TlbEntry type is used in the generic PageTable which
lives in src/mem.

Change-Id: I51b68ee74411f9af778317eff222f9349d2ed575
Reviewed-on: https://gem5-review.googlesource.com/6921
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: Define AT_RANDOM properly

According to the getauxval(3) man page, the AT_RANDOM aux value should
be a pointer to 16 random bytes. In the initial implementation of
RISC-V, this was based on spike's program stack setup, which copied the
program header table there instead. This patch changes the
implementation to use the proper 16 random bytes, making it compatible
with some RISC-V programs that use custom linker scripts.

Change-Id: Idaae7f19bf3ed3fd06d293e5e9c0b6f778270eb2
Reviewed-on: https://gem5-review.googlesource.com/6681
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Increase maximum stack size

This patch increases the maximum stack size of RISC-V, which should help
to reduce problems with programs that allocate large amounts of data on
the stack or do many small allocations.

Change-Id: I1d760050229b12f01a4a8f24c047b587299fef6d
Reviewed-on: https://gem5-review.googlesource.com/6661
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

cpu,alpha,mips,power,riscv,sparc: Get rid of eaComp and memAccInst.

Neither of these were used, particularly memAccInst.

Change-Id: I4ac9e44cf624e5de42519d586d7b699f08a2cdfc
Reviewed-on: https://gem5-review.googlesource.com/6601
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

arch-riscv: Move compressed ops out of ISA

This patch moves static portions of the compressed instruction
definitions out of the ISA generated code.

Change-Id: I61daae8b8c03a9e0f012790a132aa4d34a6ec296
Reviewed-on: https://gem5-review.googlesource.com/6026
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

misc: Rename misc.(hh|cc) to logging.(hh|cc)

These files aren't a collection of miscellaneous stuff, they're the
definition of the Logger interface, and a few utility macros for
calling into that interface (panic, warn, etc.).

Change-Id: I84267ac3f45896a83c0ef027f8f19c5e9a5667d1
Reviewed-on: https://gem5-review.googlesource.com/6226
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>

arch-riscv: use sext rather than manual masks

Replace manual creation of masks for sign extension of immediates with
the sext<N> function.

Change-Id: Ief2df91a25500c64f5bcae0dcd437c1e3bb95e6c
Reviewed-on: https://gem5-review.googlesource.com/6182
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Remove spaces around ea_code

This patch makes mem.isa conform to style guidelines better by removing
spaces around the "ea_code" argument default value assignment of the
Load format.

Change-Id: I1c62b99de3617a3734b128b00fb421773e021317
Reviewed-on: https://gem5-review.googlesource.com/6181
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Add missing license paragraphs

Some of the files in earlier patches rearranging instruction definitions
were missing copyright and license information. This patch adds them.

Change-Id: I2ac4910a415de6032fc0b7d4422904c682e0ad87
Reviewed-on: https://gem5-review.googlesource.com/6183
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

arch-riscv: Remove static parts of AMOs out of ISA

This patch removes the static parts of the RISC-V atomic memory
instructions out of the ISA generated code and into arch/riscv/insts. It
also makes the LR and SC instructions subclasses of MemInst from
arch/riscv/insts/mem.hh.

Change-Id: I6591f3d171045c4f1b457eb1264bbb7bd62b3e51
Reviewed-on: https://gem5-review.googlesource.com/6025
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Move parts of mem insts out of ISA

This patch moves static portions of the memory instructions out of the
ISA generated code and puts them into arch/riscv/insts. It also
simplifies the definitions of load and store instructions by giving
them a common base class.

Change-Id: Ic6930cbfc6bb02e4b3477521e57b093eac0c8803
Reviewed-on: https://gem5-review.googlesource.com/6024
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Move unknown out of ISA description

This patch removes the Unknown instruction type out of the ISA generated
code and puts it into arch/riscv/insts. Since there isn't any dynamic
behavior to it, all that's left behind is a template for creating a new
Unknown instruction.

Change-Id: If7c3258a24ecadd3e00ab74586e1740e14f028db
Reviewed-on: https://gem5-review.googlesource.com/6023
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Move standard ops out of ISA

This patch removes static portions of the standard instruction types
from the generated ISA code and puts them into arch/riscv/insts. Some
dynamically-generated content is left behind for each individual
instruction's implementation. Also, BranchOp is removed due to its
similarity with ImmOp and ImmOp and UImmOp are joined into a single
templated class, ImmOp<T>.

Change-Id: I1bf47c8b8a92a5be74a50909fcc51d8551185a2a
Reviewed-on: https://gem5-review.googlesource.com/6022
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Move static_inst into a directory

This patch creates an "insts" directory in src/arch/riscv to store
static portions of instruction definitions that aren't part of the code
generated by the ISA description. It serves as a starting point for
future patches to simplify the ISA description.

Change-Id: I6700522143f6fa6c9b18a30e1fbdc8f80cdc7afa
Reviewed-on: https://gem5-review.googlesource.com/6021
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Add missing system calls

This patch adds all system calls present in riscv-gnu-toolchain at
commit hash 65cb174. Many of them do not have implementations in gem5, so
they are just placeholders.

[Remove the variadic macro and replace it with a function that has
default arguments because variadic macros may not be portable across
compilers]
[Remove spaces around default arguments of createSyscall for better
style]
[Switch from using a loose function to using SyscallDesc's new
constructor]

Change-Id: Iff97c689109121b39df423c72d0e79c6366e31b9
Reviewed-on: https://gem5-review.googlesource.com/5322
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

alpha,arm,mips,power,riscv,sparc,x86: Merge exec decl templates.

In the ISA instruction definitions, some classes were declared with
execute, etc., functions outside of the main template because they
had CPU specific signatures and would need to be duplicated with
each CPU plugged into them. Now that the instructions always just
use an ExecContext, there's no reason for those templates to be
separate. This change folds those templates together.

Change-Id: I13bda247d3d1cc07c0ea06968e48aa5b4aace7fa
Reviewed-on: https://gem5-review.googlesource.com/5401
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

alpha,arm,mips,power,riscv,sparc,x86,isa: De-specialize ExecContexts.

The ISA parser used to generate different copies of exec functions
for each exec context class a particular CPU wanted to use. That's
since been changed so that those functions take a pointer to the base
ExecContext, so the code which would generate those extra functions
can be removed, and some functions which used to be templated on an
ExecContext subclass can be untemplated, or minimally less templated.

Now that some functions aren't going to be instantiated multiple times
with different signatures, there are also opportunities to collapse
templates and make many instruction definitions simpler within the
parser. Since those changes will be less mechanical, they're left for
later changes and will probably be done in smaller increments.

Change-Id: I0015307bb02dfb9c60380b56d2a820f12169ebea
Reviewed-on: https://gem5-review.googlesource.com/5381
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

scons: Stop generating inc.d in the isa parser.

Generating dependency/build product information in the isa parser breaks scons
idea of how a build is supposed to work. Arm twisting it into working forced
a lot of false dependencies which slowed down the build.

Change-Id: Iadee8c930fd7c80136d200d69870df7672a6b3ca
Reviewed-on: https://gem5-review.googlesource.com/5081
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>

mem: Signal the local monitor when clearing the global monitor

ARM systems require the coordination of the global and local
monitors. When the system is run without caches the global monitor is
implemented in the abstract memory object. This change adds a callback
from the abstract memory that notifies the local monitor when the
global monitor is cleared.

Additionally, for ARM systems the local monitor signals the event
register and wakes the thread context up. Subsequent wait-for-event
(WFE) instructions will be immediately signaled.

Change-Id: If6c038f3a6bea7239ba4258f07f39c7f9a30500b
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/3760
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

stats: Get rid of some kernel stats related cruft.

The kernel stat mechanism should really be refactored and moved somewhere
else, but in the mean time there's some old cruft that can be cleared away.

Change-Id: I21e725de590dda0d20bf3bc675bbe976c7b1bd86
Reviewed-on: https://gem5-review.googlesource.com/4600
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

riscv: Define register index constants using literals

To make it clearer what the register indices are for the semantically
meaningful registers defined by src/arch/riscv/registers.hh, the
constants that were defined using other constants were changed to use
the literal values of those constants. This also removes the need to
use the M5_VAR_USED attribute.

Change-Id: I7cccbe45d3d820deb5149a5925415735f6ae2e61
Reviewed-on: https://gem5-review.googlesource.com/4080
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

riscv: Disambiguate between the C and C++ versions of isnan and isinf.

When both the C and C++ versions are visible, the compiler will complain that
it doesn't know which one to use. By specifying the std namespace, it will
know to use the C++ version.

Change-Id: Ie1bbe1d95eadbad9644b4915c21f924d7d5c0b22
Reviewed-on: https://gem5-review.googlesource.com/4060
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

riscv: Fix bugs with RISC-V decoder and detailed CPUs

This patch fixes some bugs that were missed with the changes to the
decoder that enabled compatibility with compressed instructions. In
order to accommodate speculation with variable instruction widths, a few
assertions in decoder had to be changed to returning faults as the
specification describes should normally happen. The rest of these
assertions will be changed in a later patch.

[Remove commented-out debugging line and add clarifying comment to
registerName in utility.hh.]

Change-Id: I3f333008430d4a905cb59547a3513f5149b43b95
Reviewed-on: https://gem5-review.googlesource.com/4041
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

riscv: Add unused attribute to some registers.hh constants

Three of the constants defined in arch/riscv/registers.hh
(ReturnValueReg, SyscallNumReg, and SyscallPseudoReturnReg) may cause
the compiler to warn that they are unused, which results in an error.
This patch adds M5_VAR_USED attributes to them to stop this.

Change-Id: Ie6389a55e8ffb3d003a47d02e76bdf9fb5219457
Reviewed-on: https://gem5-review.googlesource.com/4040
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Add support for compressed extension RV64C

This patch adds compatibility with the 64-bit compressed extension to
the RISC-V ISA, RV64C. Current versions of the toolchain may use
compressed instructions in glibc by default, which can only be
overridden by recompiling the entire toolchain (simply adding
"-march=rv64g" or "-march=rv64imafd" when compiling a binary is not
sufficient to use uncompressed instructions in glibc functions in the
binary).

[Update diassembly generation for new RegId type.]
[Rebase onto master.]

Change-Id: Ifd5a5ea746704ce7e1b111442c3eb84c509a98b4
Reviewed-on: https://gem5-review.googlesource.com/3860
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

arch-riscv: Restructure ISA description

This patch restructures the RISC-V ISA description to use fewer classes
and improve its ability to be extended with nonstandard extensions in
the future. It also cleans up the disassembly for some of the CSR and
system instructions by removing source and destination registers for
instructions that don't have any.

[Fix class UImmOp to have an "imm" member rather than "uimm".]
[Update disassembly generation for new RegId class.]

Change-Id: Iec1c782020126e5e8e73460b84e31c7b5a5971d9
Reviewed-on: https://gem5-review.googlesource.com/3800
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

cpu: Added interface for vector reg file

This patch adds some more functionality to the cpu model and the arch to
interface with the vector register file.

This change consists mainly of augmenting ThreadContexts and ExecContexts
with calls to get/set full vectors, underlying microarchitectural elements
or lanes. Those are meant to interface with the vector register file. All
classes that implement this interface also get an appropriate implementation.

This requires implementing the vector register file for the different
models using the VecRegContainer class.

This change set also updates the Result abstraction to contemplate the
possibility of having a vector as result.

The changes also affect how the remote_gdb connection works.

There are some (nasty) side effects, such as the need to define dummy
numPhysVecRegs parameter values for architectures that do not implement
vector extensions.

Nathanael Premillieu's work with an increasing number of fixes and
improvements of mine.

Change-Id: Iee65f4e8b03abfe1e94e6940a51b68d0977fd5bb
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
[ Fix RISCV build issues and CC reg free list initialisation ]
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2705

cpu: Simplify the rename interface and use RegId

With the hierarchical RegId there are a lot of functions that are
redundant now.

The idea behind the simplification is that instead of having the regId,
telling which kind of register read/write/rename/lookup/etc. and then
the function panic_if'ing if the regId is not of the appropriate type,
we provide an interface that decides what kind of register to read
depending on the register type of the given regId.

Change-Id: I7d52e9e21fc01205ae365d86921a4ceb67a57178
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
[ Fix RISCV build issues ]
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2702

arch, cpu: Architectural Register structural indexing

Replace the unified register mapping with a structure associating
a class and an index. It is now much easier to know which class of
register the index is referring to. Also, when adding a new class
there is no need to modify existing ones.

Change-Id: I55b3ac80763702aa2cd3ed2cbff0a75ef7620373
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
[ Fix RISCV build issues ]
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2700

arch-riscv: Fix bad stack initialization

This patch fixes a problem with RISC-V initial stack setup in SE mode
where the AT_RANDOM aux vector value contains an address that is too
close to the top of the stack and doesn't fit the required 16 bytes. To
fix this, the program header table was added to the top of the stack
just like the RISC-V proxy kernel does.

Change-Id: I814562e060ff041cd0d7a7c54c3685645bd325a3
Reviewed-on: https://gem5-review.googlesource.com/3401
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

base: Refactor the GDB code.

The new version modularizes the implementation of the various commands,
gets rid of dynamic allocation of the register cache, fixes some small
style problems, and uses exceptions to simplify error handling internal to
the GDB stub.

Change-Id: Iff3548373ce4adfb99106a810f5713b769df89b2
Reviewed-on: https://gem5-review.googlesource.com/3280
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

syscall_emul, riscv: add override keyword to RISCV Process class

Change-Id: I2a146ae57aac3787389997961208474a97e7c155
Reviewed-on: https://gem5-review.googlesource.com/3360
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

riscv: Fix crashes with large or frequent mmaps

This patch fixes a bug where increasing the mmap region too much causes
it to run into already-allocated memory, which causes gem5 to fail an
assertion. Previously, the stack was incorrectly set up such that the
end of the mmap region and the top of the stack were the same address
and both would grow downward. With this patch, the top of the stack has
been separated from the end of mmap and moved up, and the mmap region
now grows upward instead of downward.

[Rebase to master branch and remove dependencies.]

Change-Id: I7271ff478fff2994f918bc5003a6139b9ba6a520
Reviewed-on: https://gem5-review.googlesource.com/2680
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

riscv: fix Linux problems with LR and SC ops

Some of the functions in the Linux toolchain that allocate memory make
use of paired LR and SC instructions, which didn't work properly for
that toolchain. This patch fixes that so attempting to use those
functions doesn't cause an endless loop of failed SC instructions.

Change-Id: If27696323dd6229a0277818e3744fbdf7180fca7
Reviewed-on: https://gem5-review.googlesource.com/2340
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

riscv: fix compatibility with Linux toolchain

Previously, RISC-V in gem5 only supported RISC-V's Newlib toolchain
(riscv64-unknown-elf-*) due to incorrect assumptions made in the initial
setup of the user stack in SE mode. This patch fixes that by referring
to the RISC-V proxy kernel code (https://github.com/riscv/riscv-pk) and
setting up the stack according to how it does it. Now binaries compiled
using the Linux toolchain (riscv64-unknown-linux-gnu-*) will run as
well.

[Update for recent changes to MemState to add accessors and mutators to
get its members.]

Change-Id: I6d2c486df7688efe3df54273e9aa0fd686851285
Reviewed-on: https://gem5-review.googlesource.com/2305
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

riscv: add remote gdb support

This patch adds support for debugging with remote GDB to RISC-V. Using
GDB compiled with the RISC-V GNU toolchain, it is possible to pause
and continue execution, view debugging information, etc. As with the
rest of RISC-V, this does not support full-system mode.

Change-Id: I2d3a8be614725e1be4b4c283f9fb678a0a30578d
Reviewed-on: https://gem5-review.googlesource.com/2304
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

riscv: fix error on memory op address overflow

Previously, if a memory operation referenced an address that caused the
data to wrap around to the beginning of the memory (such as -1 or
0xFFFFFFFFFFFFFFFF), an assert would fail during address translation and
gem5 would crash. This patch fixes that by checking for such a case in
RISC-V's TLB code and returning a fault from translateData if that would
happen. Because RISC-V does support unaligned memory accesses, no
checking is performed to make sure that an access doesn't cross a cache
line.

[Update creation of page table fault to use make_shared.]
[Add comment explaining the change and assertion that the memory request
isn't zero size.]

Change-Id: I7b8ef9a5838f30184dbdbd0c7c1655e1c04a9410
Reviewed-on: https://gem5-review.googlesource.com/2345
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

riscv: enable unaligned memory accesses

Sometimes an ld instruction will be split across a
cache boundary. Previously RISC-V was set to not
allow this. This patch fixes that.

Change-Id: I8bc8ea6d67f65a9b3662e14c4037f4224799d20f
Reviewed-on: https://gem5-review.googlesource.com/2341
Maintainer: Alec Roelke <ar4jc@virginia.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

syscall-emul: Rewrite system call exit code

The changeset does a major refactor on the exit, exit_group, and
futex system calls regarding exit functionality.

A FutexMap class and related structures are added into a new
file. This increases code clarity by encapsulating the futex
operations and the futex state into an object.

Several exit conditions were added to allow the simulator to end
processes under certain conditions. Also, the simulation only
exits now when all processes have finished executing.

Change-Id: I1ee244caa9b5586fe7375e5b9b50fd3959b9655e
Reviewed-on: https://gem5-review.googlesource.com/2269
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

syscall-emul: Move memState into its own file

The Process class is full of implementation details and
structures related to SE Mode. This changeset factors out an
internal class from Process and moves it into a separate file.
The purpose behind doing this is to clean up the code and make
it a bit more modular.

Change-Id: Ic6941a1657751e8d51d5b6b1dcc04f1195884280
Reviewed-on: https://gem5-review.googlesource.com/2263
Reviewed-by: Jason Lowe-Power <jason@lowepower.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 13/22] add system call retry capability

This changeset adds functionality that allows system calls to retry without
affecting thread context state such as the program counter or register values
for the associated thread context (when system calls return with a retry
fault).

This functionality is needed to solve problems with blocking system calls
in multi-process or multi-threaded simulations where information is passed
between processes/threads. Blocking system calls can cause deadlock because
the simulator itself is single threaded. There is only a single thread
servicing the event queue which can cause deadlock if the thread hits a
blocking system call instruction.

To illustrate the problem, consider two processes using the producer/consumer
sharing model. The processes can use file descriptors and the read and write
calls to pass information to one another. If the consumer calls the blocking
read system call before the producer has produced anything, the call will
block the event queue (while executing the system call instruction) and
deadlock the simulation.

The solution implemented in this changeset is to recognize that the system
calls will block and then generate a special retry fault. The fault will
be sent back up through the function call chain until it is exposed to the
cpu model's pipeline where the fault becomes visible. The fault will trigger
the cpu model to replay the instruction at a future tick where the call has
a chance to succeed without actually going into a blocking state.

In subsequent patches, we recognize that a syscall will block by calling a
non-blocking poll (from inside the system call implementation) and checking
for events. When events show up during the poll, it signifies that the call
would not have blocked and the syscall is allowed to proceed (calling an
underlying host system call if necessary). If no events are returned from the
poll, we generate the fault and try the instruction for the thread context
at a distant tick. Note that retrying every tick is not efficient.

As an aside, the simulator has some multi-threading support for the event
queue, but it is not used by default and needs work. Even if the event queue
was completely multi-threaded, meaning that there is a hardware thread on
the host servicing a single simulator thread contexts with a 1:1 mapping
between them, it's still possible to run into deadlock due to the event queue
barriers on quantum boundaries. The solution of replaying at a later tick
is the simplest solution and solves the problem generally.

syscall_emul: [patch 8/22] refactor process class

Moves aux_vector into its own .hh and .cc files just to get it out of the
already crowded Process files. Arguably, it could stay there, but it's
probably better just to move it and give it files.

The changeset looks ugly around the Process header file, but the goal here is
to move methods and members around so that they're not defined randomly
throughout the entire header file. I expect this is likely one of the reasons
why I several unused variables related to this class. So, the methods are
declared first followed by members. I've tried to aggregate them together
so that similar entries reside near one another.

There are other changes coming to this code so this is by no means the
final product.

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.

riscv: Fix crash when syscall argument reg index is too high

By default, doSyscall gets the values of six registers to be used for
system call arguments. RISC-V, by convention, only has four. Because
RISC-V's implementation of these indices is as arrays of integers rather
than as base indices plus offsets, trying to get the fifth argument
register's value will cause a crash. This patch fixes that by returning 0
for any index higher than 3.

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

style: [patch 3/22] reduce include dependencies in some headers

Used cppclean to help identify useless includes and removed them. This
involved erroneously included headers, but also cases where forward
declarations could have been used rather than a full include.

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.

riscv: [Patch 7/5] Corrected LRSC semantics

RISC-V makes use of load-reserved and store-conditional instructions to
enable creation of lock-free concurrent data manipulation as well as
ACQUIRE and RELEASE semantics for memory ordering of LR, SC, and AMO
instructions (the latter of which do not follow LR/SC semantics). This
patch is a correction to patch 4, which added these instructions to the
implementation of RISC-V. It modifies locked_mem.hh and the
implementations of lr.w, sc.w, lr.d, and sc.d to apply the proper gem5
flags and return the proper values.

An important difference between gem5's LLSC semantics and RISC-V's LR/SC
ones, beyond the name, is that gem5 uses 0 to indicate failure and 1 to
indicate success, while RISC-V is the opposite. Strictly speaking, RISC-V
uses 0 to indicate success and nonzero to indicate failure where the
value would indicate the error, but currently only 1 is reserved as a
failure code by the ISA reference.

This is the seventh patch in the series which originally consisted of five
patches that added the RISC-V ISA to gem5. The original five patches added
all of the instructions and added support for more detailed CPU models and
the sixth patch corrected the implementations of Linux constants and
structs. There will be an eighth patch that adds some regression tests
for the instructions.

[Removed some commented-out code from locked_mem.hh.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>

riscv: [Patch 6/5] Improve Linux emulation for RISC-V

This is an add-on patch for the original series that implemented RISC-V
that improves the implementation of Linux emulation for SE mode. Basically
it cleans up linux/linux.hh by removing constants that haven't been
defined for the RISC-V Linux proxy kernel and rearranging the stat
struct so it aligns with RISC-V's implementation of it. It also adds
placeholders for system calls that have been given numbers in RISC-V
but haven't been given implementations yet. These system calls are
as follows:
- readlinkat
- sigprocmask
- ioctl
- clock_gettime
- getrusage
- getrlimit
- setrlimit

The first five patches implemented RISC-V with the base ISA and multiply,
floating point, and atomic extensions and added support for detailed
CPU models with memory timing.

[Fixed incompatibility with changes made from patch 1.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>

riscv: [Patch 5/5] Added missing support for timing CPU models

Last of five patches adding RISC-V to GEM5. This patch adds support for
timing, minor, and detailed CPU models that was missing in the last four,
which basically consists of handling timing-mode memory accesses and
telling the minor and detailed models what a no-op instruction should
be (addi zero, zero, 0).

Patches 1-4 introduced RISC-V and implemented the base instruction set,
RV64I, and added the multiply, floating point, and atomic memory
extensions, RV64MAFD.

[Fixed compatibility with edit from patch 1.]
[Fixed compatibility with hg copy edit from patch 1.]
[Fixed some style errors in locked_mem.hh.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>

riscv: [Patch 4/5] Added RISC-V atomic memory extension RV64A

Fourth of five patches adding RISC-V to GEM5. This patch adds the RV64A
extension, which includes atomic memory instructions. These instructions
atomically read a value from memory, modify it with a value contained in a
source register, and store the original memory value in the destination
register and modified value back into memory. Because this requires two
memory accesses and GEM5 does not support two timing memory accesses in
a single instruction, each of these instructions is split into two micro-
ops: A "load" micro-op, which reads the memory, and a "store" micro-op,
which modifies and writes it back. Each atomic memory instruction also has
two bits that acquire and release a lock on its memory location.
Additionally, there are atomic load and store instructions that only either
load or store, but not both, and can acquire or release memory locks.

Note that because the current implementation of RISC-V only supports one
core and one thread, it doesn't make sense to make use of AMO instructions.
However, they do form a standard extension of the RISC-V ISA, so they are
included mostly as a placeholder for when multithreaded execution is
implemented. As a result, any tests for their correctness in a future
patch may be abbreviated.

Patch 1 introduced RISC-V and implemented the base instruction set, RV64I;
patch 2 implemented the integer multiply extension, RV64M; and patch 3
implemented the single- and double-precision floating point extensions,
RV64FD.

Patch 5 will add support for timing, minor, and detailed CPU models that
isn't present in patches 1-4.

[Added missing file amo.isa]
[Replaced information removed from initial patch that was missed during
division into multiple patches.]
[Fixed some minor formatting issues.]
[Fixed oversight where LR and SC didn't have both AQ and RL flags.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>

riscv: [Patch 3/5] Added RISCV floating point extensions RV64FD

Third of five patches adding RISC-V to GEM5. This patch adds the RV64FD
extensions, which include single- and double-precision floating point
instructions.

Patch 1 introduced RISC-V and implemented the base instruction set, RV64I
and patch 2 implemented the integer multiply extension, RV64M.

Patch 4 will implement the atomic memory instructions, RV64A, and patch
5 will add support for timing, minor, and detailed CPU models that is
missing from the first four patches.

[Fixed exception handling in floating-point instructions to conform better
to IEEE-754 2008 standard and behavior of the Chisel-generated RISC-V
simulator.]
[Fixed style errors in decoder.isa.]
[Fixed some fuzz caused by modifying a previous patch.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>

riscv: [Patch 2/5] Added RISC-V multiply extension RV64M

Second of five patches adding RISC-V to GEM5. This patch adds the
RV64M extension, which includes integer multiply and divide instructions.

Patch 1 introduced RISC-V and implemented the base instruction set, RV64I.

Patch 3 will implement the floating point extensions, RV64FD; patch 4 will
implement the atomic memory instructions, RV64A; and patch 5 will add
support for timing, minor, and detailed CPU models that is missing from
the first four patches.

[Added mulw instruction that was missed when dividing changes among
patches.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>

arch: [Patch 1/5] Added RISC-V base instruction set RV64I

First of five patches adding RISC-V to GEM5. This patch introduces the
base 64-bit ISA (RV64I) in src/arch/riscv for use with syscall emulation.
The multiply, floating point, and atomic memory instructions will be added
in additional patches, as well as support for more detailed CPU models.
The loader is also modified to be able to parse RISC-V ELF files, and a
"Hello world\!" example for RISC-V is added to test-progs.

Patch 2 will implement the multiply extension, RV64M; patch 3 will implement
the floating point (single- and double-precision) extensions, RV64FD;
patch 4 will implement the atomic memory instructions, RV64A, and patch 5
will add support for timing, minor, and detailed CPU models that is missing
from the first four patches (such as handling locked memory).

[Removed several unused parameters and imports from RiscvInterrupts.py,
RiscvISA.py, and RiscvSystem.py.]
[Fixed copyright information in RISC-V files copied from elsewhere that had
ARM licenses attached.]
[Reorganized instruction definitions in decoder.isa so that they are sorted
by opcode in preparation for the addition of ISA extensions M, A, F, D.]
[Fixed formatting of several files, removed some variables and
instructions that were missed when moving them to other patches, fixed
RISC-V Foundation copyright attribution, and fixed history of files
copied from other architectures using hg copy.]
[Fixed indentation of switch cases in isa.cc.]
[Reorganized syscall descriptions in linux/process.cc to remove large
number of repeated unimplemented system calls and added implmementations
to functions that have received them since it process.cc was first
created.]
[Fixed spacing for some copyright attributions.]
[Replaced the rest of the file copies using hg copy.]
[Fixed style check errors and corrected unaligned memory accesses.]
[Fix some minor formatting mistakes.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>