it's possible for the offset provided to an HSAIL mem inst to be a negative
value, however the variable we use to hold the offset is an unsigned type.
this can lead to excessively large offset values when the offset is negative,
which will almost certainly cause the access to go out of bounds.
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>
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>
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>
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>
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>
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>
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>
UBSAN flags this operation because it detects that arg is being cast directly
to an unsigned type, argBits. this patch fixes this by first casting the
value to a signed int type, then reintrepreting the raw bits of the signed
int into argBits.
fixes to appease clang++. tested on:
Ubuntu clang version 3.5.0-4ubuntu2~trusty2
(tags/RELEASE_350/final) (based on LLVM 3.5.0)
Ubuntu clang version 3.6.0-2ubuntu1~trusty1
(tags/RELEASE_360/final) (based on LLVM 3.6.0)
the fixes address the following five issues:
1) the exec continuations in gpu_static_inst.hh were marked
as protected when they should be public. here we mark
them as public
2) the Abs instruction uses std::abs() in its execute method.
because Abs is templated, it can also operate on U32 and U64,
types, which cause Abs::execute() to pass uint32_t and uint64_t
types to std::abs() respectively. this triggers a warning
because std::abs() has no effect in this case. to rememdy this
we add template specialization for the execute() method of Abs
when its template paramter is U32 or U64.
3) Some potocols that utilize the code in cprintf.hh were missing
includes to BoolVec.hh, which defines operator<< for the BoolVec
type. This would cause issues when the generated code would try
to pass a BoolVec type to a method in cprintf.hh that used
operator<< on an instance of a BoolVec.
4) Surprise, clang doesn't like it when you clobber all the bits
in a newly allocated object. I.e., this code:
tlb = new GpuTlbEntry\[size\];
std::memset(tlb, 0, sizeof(GpuTlbEntry) \* size);
Let's use std::vector to track the TLB entries in the GpuTlb now...
5) There were a few variables used only in DPRINTFs, so we mark them
with M5_VAR_USED.
This patch adds the ability for an application to request dist-gem5 to begin/
end synchronization using an m5 op. When toggling on sync, all nodes agree
on the next sync point based on the maximum of all nodes' ticks. CPUs are
suspended until the sync point to avoid sending network messages until sync has
been enabled. Toggling off sync acts like a global execution barrier, where
all CPUs are disabled until every node reaches the toggle off point. This
avoids tricky situations such as one node hitting a toggle off followed by a
toggle on before the other nodes hit the first toggle off.
this patch adds an ordered response buffer to the GM pipeline
to ensure in-order data delivery. the buffer is implemented as
a stl ordered map, which sorts the request in program order by
using their sequence ID. when requests return to the GM pipeline
they are marked as done. only the oldest request may be serviced
from the ordered buffer, and only if is marked as done.
the FIFO response buffers are kept and used in OoO delivery mode
for HSAIL an operand's indices into the register files may be calculated
trivially, because the operands are always read from a register file, or are
an immediate.
for machine ISA, however, an op selector may specify special registers, or
may specify special SGPRs with an alias op selector value. the location of
some of the special registers values are dependent on the size of the RF
in some cases. here we add a way for the underlying getRegisterIndex()
method to know about the size of the RFs, so that it may find the relative
positions of the special register values.
currently the PC is incremented on an instruction granularity, and not as an
instruction's byte address. machine ISA instructions assume the PC is a byte
address, and is incremented accordingly. here we make the GPU model, and the
HSAIL instructions treat the PC as a byte address as well.
the GPUISA class is meant to encapsulate any ISA-specific behavior - special
register accesses, isa-specific WF/kernel state, etc. - in a generic enough
way so that it may be used in ISA-agnostic code.
gpu-compute: use the GPUISA object to advance the PC
the GPU model treats the PC as a pointer to individual instruction objects -
which are store in a contiguous array - and not a byte address to be fetched
from the real memory system. this is ok for HSAIL because all instructions
are considered by the model to be the same size.
in machine ISA, however, instructions may be 32b or 64b, and branches are
calculated by advancing the PC by the number of words (4 byte chunks) it
needs to advance in the real instruction stream. because of this there is
a mismatch between the PC we use to index into the instruction array, and
the actual byte address PC the ISA expects. here we move the PC advance
calculation to the ISA so that differences in the instrucion sizes may be
accounted for in generic way.
because every taken branch causes fetch to be discarded, we move the call
to the WF to avoid to have to call it from each and every branch instruction
type.
we are removing doGmReturn from the GM pipe, and adding completeAcc()
implementations for the HSAIL mem ops. the behavior in doGmReturn is
dependent on HSAIL and HSAIL mem ops, however the completion phase
of memory ops in machine ISA can be very different, even amongst individual
machine ISA mem ops. so we remove this functionality from the pipeline and
allow it to be implemented by the individual instructions.
this patch removes the GPUStaticInst enums that were defined in GPU.py.
instead, a simple set of attribute flags that can be set in the base
instruction class are used. this will help unify the attributes of HSAIL
and machine ISA instructions within the model itself.
because the static instrution now carries the attributes, a GPUDynInst
must carry a pointer to a valid GPUStaticInst so a new static kernel launch
instruction is added, which carries the attributes needed to perform a
the kernel launch.
Modify the opClass assigned to AArch64 FP instructions from SimdFloat* to
Float*. Also create the FloatMemRead and FloatMemWrite opClasses, which
distinguishes writes to the INT and FP register banks.
Change the latency of (Simd)FloatMultAcc to 5, based on the Cortex-A72,
where the "latency" of FMADD is 3 if the next instruction is a FMADD and
has only the augend to destination dependency, otherwise it's 7 cycles.
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Normal MMAPPED_IPR requests are allowed to execute speculatively under the
assumption that they have no side effects. The special case of m5ops that are
treated like MMAPPED_IPR should not be allowed to execute speculatively, since
they can have side-effects. Adding the STRICT_ORDER flag to these requests
blocks execution until the associated instruction hits the ROB head.
this patch fixes issues with changeset 11593
use the host's pwrite() syscall for pwrite64Func(),
as opposed to pwrite64(), because pwrite64() does
not work well on all distros.
undo the enabling of fstatfs, as we will add this
in a separate pate.
Introduce and use a lookup table.
Using fetchDescriptor() rather than DMA cleanly handles nested paging.
Change-Id: I69ec762f176bd752ba1040890e731826b58d15a6
During host bootup, KVM reads/writes to CNTHCTL_EL2. Because this
miscreg has not been implemented, the simulation would end there. This
patch causes the simulation to warn about the read/write instead of fail.
Change-Id: If034bfd0818a9a5e50c5fe86609e945258c96fa3
This fixes a bug where stage 2 lookups used the AArch32
permissions rules even if we were executing in AArch64 mode.
Change-Id: Ia40758f0599667ca7ca15268bd3bf051342c24c1
This patch restricts trapping to hypervisor only if we are in the
correct exception level for the trap to happen.
Change-Id: I0a382b6a572ef835ea36d2702b8a81b633bd3df0
Faults that could potentially be routed to the hypervisor checked
whether or not they were in a secure state without checking if security
was enabled or not. This caused faults not to be routed correctly. This
patch causes secure state checking to first ask if security is enabled.
Change-Id: I179e9b181b27f552734c9bab2b18d05ac579a119
We recompute if we are doing a stage 2 walk inside of the table walker
but we have already figured it out in the tlb. Pass the information in
to the walk instead of recomputing it.
Change-Id: I39637ce99309b2ddbc30344d45ac9ebf6a203401
The functional case is already handled within the fetchDescriptor()
function. We can thus use that function for both atomic and functional
mode when we start the table walk.
Change-Id: Iacaed28cd9024d259fd37a58150efd00ff94d86e
This patch adds the option for faults to be routed to the hypervisor
using the pre-existing routeToHyp() functions that are present in each
fault type.
Change-Id: I9735512c094457636b9870456a5be5432288e004
During address translation instructions (such as AT S1E1R_Xt) the exception
level can be different than the current exception level. This patch fixes
how the TLB determines what EL to use during these instructions.
Change-Id: Ia9ce229404de9e284bc1f7479fd2c580efd55f8f
This patch adds the AArch64 instruction hvc which raises an exception
from EL1 into EL2. The host OS uses this instruction to world switch
into the guest.
Change-Id: I930ee43f4f0abd4b35a68eb2a72e44e3ea6570be
Make it so that getInterrupt *always* returns an interrupt if
checkInterrupts() returns true. This fixes/simplifies handling
of interrupts on the SMT FS CPUs (currently minor).
Don't consult the TLB test interface for PA's returned by functional
translations by the AT instruction. We implement this by chaning the
ISA code to synthesize 0-length functional reads for the TLB lookup.
The TLB then bypasses the final PA check in the tester if the size is
zero.
Change-Id: I2487b7f829cea88c37e229e9fc7a4543aced961b
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Previously when we initialized the TLB we would allocate a number of
TLB entries which would be marked as valid. As a result the TLB
contained an entry which would be considered a valid entry for the 0
page.
Change-Id: I23ace86426a171a4f6200ebeb29ad57c21647036
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
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>
There is a mismatch between DataType and SrcDataType in constructing
Atomic ST instruction. The mismatch causes atomic_store and
atomic_store_explicit function to store incorrect value in memory.
Eliminate the VSZ constant that defined the Wavefront size (in numbers of work
items); replaced it with a parameter in the GPU.py configuration script.
Changed all data structures dependent on the Wavefront size to be dynamically
sized. Legal values of Wavefront size are 16, 32, 64 for now and checked at
initialization time.
Fixing an issue with regStats not calling the parent class method
for most SimObjects in Gem5. This causes issues if one adds new
stats in the base class (since they are never initialized properly!).
Change-Id: Iebc5aa66f58816ef4295dc8e48a357558d76a77c
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
We want to extend the stats of objects hierarchically and thus it is necessary
to register the statistics of the base-class(es), as well. For now, these are
empty, but generic stats will be added there.
Patch originally provided by Akash Bagdia at ARM Ltd.
In particular, when EL0 is in AArch32 but EL1 is AArch64, AArch64
memory translation must be used. This is essential for typical
AArch64/32 interworking use cases.
The ERET instruction doesn't set PSTATE correctly in some cases
(particularly when returning to aarch32 code). Among other things,
this breaks EL0 thumb code when using a 64-bit kernel. This changeset
updates the ERET implementation to match the ARM ARM.
Change-Id: I408e7c69a23cce437859313dfe84e68744b07c98
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nathanael Premillieu <nathanael.premillieu@arm.com>
The current implementation of aarch32 FP/SIMD in gem5 assumes that EL1
and higher are all 32-bit. This breaks interprocessing since an
aarch64 EL1 uses different enable/disable bits. This change updates
the permission checks to according to what is prescribed by the ARM
ARM.
Change-Id: Icdcef31b00644cfeebec00216b3993aa1de12b88
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Mitch Hayenga <mitch.hayenga@arm.com>
Reviewed-by: Nathanael Premillieu <nathanael.premillieu@arm.com>
LPAE has been tested with Linux 4.4 and seems to work just fine. Let's
enable it by default.
Change-Id: Id88c6e3c91ae9c353279d42f2aa1f8a78485bd32
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>
According to the ARM ARM (see AArch32.TranslateAddress in the
pseudocode library), the TLB should be operating in aarch64 mode if
the EL0 is aarch32 and EL1 is aarch64. This is currently not the case
in gem5, which breaks 64/32 interprocessing. Update the check to match
the reference manual.
Change-Id: I6f1444d57c0e2eb5f8880f513f33a9197b7cb2ce
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Mitch Hayenga <mitch.hayenga@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
We currently check the current state instead of the state of the
target EL when determining how we report a fault. This breaks
interprocessing since EL0 in aarch32 would report its fault status
using the aarch32 registers even if EL1 is in aarch64. Fix this to
report the fault using the format of the target EL.
Change-Id: Ic080267ac210783d1e01c722a4ddaa687dce280e
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Mitch Hayenga <mitch.hayenga@arm.com>
The TLB currently assumes that the pxn bit in an LPAE page descriptor
disables execution from unprivileged mode. However, according to the
architecture manual, this bit should disable execution from privileged
modes. Update the TLB implementation to reflect this behavior.
Change-Id: I7f1bb232d7a94a93fd601a9230223195ac952947
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
A lot of code assumes that it is possible to test what the highest EL
is and if it is 64 bit. These calls currently don't work in SE mode
since they rely on an instance of an ArmSystem.
Change-Id: I0d1f261926a66ce3dc4fa116845ffb2a081446f2
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Nathanael Premillieu <nathanael.premillieu@arm.com>
This patch fixes an issue identified by ASAN where the Neon64Load
operation assumes the packet always contains 16 bytes.
Change-Id: If24a7e461d60cb80970dfbe61d923d7d56926698
Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
According to the Intel Multi Processor Specification rev 1.4 (-006) (*),
section 4.3.2 Bus Entries, Bus type strings are >>6-character ASCII
(blank-filled) strings<<.
This patch properly pads the entries with the missing spaces at the end.
(*) http://www.intel.com/design/pentium/datashts/24201606.pdf
Committed by Jason Lowe-Power <power.jg@gmail.com>
Registers are 0x10 and not 0x8 apart. The latter leads to invalid
calculations of index in array which in turn means that we will not
find the interrupt we were looking (been notified) for in the OS.
Committed by Jason Lowe-Power <power.jg@gmail.com>
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>
Add support for overriding the number of interrupt lines in the ARM
KvmGic.
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Radhika Jagtap <radhika.jagtap@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Factor out the kernel device wrapper from the KvmGIC and put it in a
separate class. This will simplify a future kernel/gem5 hybrid GIC.
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Radhika Jagtap <radhika.jagtap@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Remve the assertion that we always need to add a delta larger than
zero as that does not seem to be true when we hit it in the
'PMU reset cycle counter to zero' case.
Committed by Jason Lowe-Power <power.jg@gmail.com>
A few warnings (and thus errors) pop up after being added to -Wall:
1. -Wmisleading-indentation
In the auto-generated code there were instances of if/else blocks that
were not indented to gcc's liking. This is addressed by adding braces.
2. -Wshift-negative-value
gcc is clever enougn to consider ~0 a negative constant, and
rightfully complains. This is addressed by using mask() which
explicitly casts to unsigned before shifting.
That is all. Porting done.
In general, the ThreadID parameter is unnecessary in the memory system
as the ContextID is what is used for the purposes of locks/wakeups.
Since we allocate sequential ContextIDs for each thread on MT-enabled
CPUs, ThreadID is unnecessary as the CPUs can identify the requesting
thread through sideband info (SenderState / LSQ entries) or ContextID
offset from the base ContextID for a cpu.
This is a re-spin of 20264eb after the revert (bd1c6789) and includes
some fixes of that commit.
The following patches had unexpected interactions with the current
upstream code and have been reverted for now:
e07fd01651f3: power: Add support for power models
831c7f2f9e39: power: Low-power idle power state for idle CPUs
4f749e00b667: power: Add power states to ClockedObject
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
--HG--
extra : amend_source : 0b6fb073c6bbc24be533ec431eb51fbf1b269508
In general, the ThreadID parameter is unnecessary in the memory system
as the ContextID is what is used for the purposes of locks/wakeups.
Since we allocate sequential ContextIDs for each thread on MT-enabled
CPUs, ThreadID is unnecessary as the CPUs can identify the requesting
thread through sideband info (SenderState / LSQ entries) or ContextID
offset from the base ContextID for a cpu.
Add 4 power states to the ClockedObject, provides necessary access functions
to check and update the power state. Default power state is UNDEFINED, it is
responsibility of the respective simulation model to provide the startup state
and any other logic for state change.
Add number of transition stat.
Add distribution of time spent in clock gated state.
Add power state residency stat.
Add dump call back function to allow stats update of distribution and residency
stats.
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.
Refactor the TLB and page table walker test interface to use a dynamic
registration mechanism. Instead of patching a couple of empty methods
to wire up a TLB tester, this change allows such testers to register
themselves using the setTestInterface() method.
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.)
The mmapGrowsDown() method was a static method on the OperatingSystem
class (and derived classes), which worked OK for the templated syscall
emulation methods, but made it hard to access elsewhere. This patch
moves the method to be a virtual function on the LiveProcess method,
where it can be overridden for specific platforms (for now, Alpha).
This patch also changes the value of mmapGrowsDown() from being false
by default and true only on X86Linux32 to being true by default and
false only on Alpha, which seems closer to reality (though in reality
most people use ASLR and this doesn't really matter anymore).
In the process, also got rid of the unused mmap_start field on
LiveProcess and OperatingSystem mmapGrowsUp variable.
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.
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.
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>
This patch adds assertions that enforce that only invalidating snoops
will ever reach into the logic that tracks in-order load completion and
also invalidation of LL/SC (and MONITOR / MWAIT) monitors. Also adds
some comments to MSHR::replaceUpgrades().
Properly done for the ERET instruction in v8, but not for v7.
Many control register changes are only visible after explicit
instruction synchronization barriers or exception entry/exit.
This means mode changing instructions should squash any
younger in-flight speculative instructions.
The previous implementation did a pair of nested RMW operations,
which isn't compatible with the way that locked RMW operations are
implemented in the cache models. It was convenient though in that
it didn't require any new micro-ops, and supported cmpxchg16b using
64-bit memory ops. It also worked in AtomicSimpleCPU where
atomicity was guaranteed by the core and not by the memory system.
It did not work with timing CPU models though.
This new implementation defines new 'split' load and store micro-ops
which allow a single memory operation to use a pair of registers as
the source or destination, then uses a single ldsplit/stsplit RMW
pair to implement cmpxchg. This patch requires support for 128-bit
memory accesses in the ISA (added via a separate patch) to support
cmpxchg16b.
Although the cache models support wider accesses, the ISA descriptions
assume that (for the most part) memory operands are integer types,
which makes it difficult to define instructions that do memory accesses
larger than 64 bits.
This patch adds some generic support for memory operands that are arrays
of uint64_t, and specifically a 'u2qw' operand type for x86 that is an
array of 2 uint64_ts (128 bits). This support is unused at this point,
but will be needed shortly for cmpxchg16b. Ideally the 128-bit SSE
memory accesses will also be rewritten to use this support.
Support for 128-bit accesses could also have been added using the gcc
__int128_t extension, which would have been less disruptive. However,
although clang also supports __int128_t, it's still non-standard.
Also, more importantly, this approach creates a path to defining
256- and 512-byte operands as well, which will be useful for eventual
AVX support.
