The page table walker might need to write back page table entries to set
their accessed bits. It was already checking whether the access was 32
or 64 bit when the PTE was retrieved from the incoming packet, but was
not checking the size when it was written back out, causing an assert to
fail when working with 32 bit legacy PTEs.
Change-Id: I7d02241cad20681e6cac0111edf2454335c466fa
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55808
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The default MTYPE initialization in the emulated GPU driver is currently
doing a bitwise AND on an input integer param with other integers
instead of using a bitmask. Change this to use bitset and test the bit
positions corresponding to the values in the MTYPE enum that were
previously being used as an operand for bitwise AND.
This was causing invalid slicc transitions in some benchmarks for
combinations of request type and mtype that are undefined.
Change-Id: I93fee0eae1fff7141cd14c239c16d1d69925d08d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56367
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The VIPER configuration uses the MOESI_AMD_Base protocol's directory.
This protocol does not wait for memory ACKs. As a result, this can lead
to read requests being pulled out of the MessageBuffer between the
directory and DRAMCtrl before a write request to the same address. This
leads to inconsistent data. To fix this, make the MessageBuffers
ordered. Since these MessageBuffers are essentially just an interface
between SLICC and DRAMCtrl, and DRAMCtrl can reorder requests properly,
this should not cause any large impact on performance due to the
constraint.
Also remove the duplicate instantiation of these MessageBuffers.
Change-Id: I59653717cc79884e733af3958adfc14941703958
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57411
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Matthew Poremba <matthew.poremba@amd.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This enhances MOESI_AMD_Base-dir DmaWrite to enable partial writes. This
is currently done by assuming a full cache line, invalidating caches,
and transitioning back to unblocked state. The enhanced write supports
partial writes (i.e., smaller than cache line size) by first reading
memory, merging the modified data, and then writing back to memory.
Implementation of this mirrors that of DmaRead in terms of state. This
means for each DmaRead state (BDR_PM, BDR_Pm, and BDR_M) there is a
write analogue (BDW_PM, BDW_Pm, and BDR_M) and the BDR_P state is
removed. Furthermore, this enhanced DmaWrite ... actually writes data to
memory instead of relying on DirectoryEntry / backing store for correct
data.
There are two possible state transitions for DmaWrite now. (1) Memory
data arrives before probe response and (2) probe response arrives before
memory data. In case (1), probe data overwrites memory data and merges
the partial write using the TBE write mask then updates write mask to
'filled' state. In case (2), probe data is merged with the partial data
using the TBE write mask then updates write mask to 'filled' state. The
memory data will then be clobbered by copying the TBE data over the
response since the write mask is now full.
Change-Id: I1eebb882b464c4c5ee5fd60932fd38d271ada4d7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57410
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Matthew Poremba <matthew.poremba@amd.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This protocol is using an old style where read/writes to memory were
being done by writing to a DataBlock in a DirectoryMemory entry. This
results in having multiple copies of memory, leads to stale copies in at
least one memory (usually DRAM), and require --access-backing-store in
most cases to work properly. This changeset removes all references to
getDirectoryEntry(...).DataBlk and instead forwards those reads and
writes to DRAM always.
Change-Id: If2e52151789ad82c7b55c8fa2b41c1f4e5b65994
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57409
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Now that the I8259's vector is reported using a special memory access,
the getVector method doesn't need to be accessible outside of the class.
It's still useful internally though, since it nicely encapsulates what
should happen when an INTA signal is received.
Change-Id: I7da7c1f18fac97ffc62c965978f53fb4c5430de3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55698
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This pin should be connected to the master I8259 output which is used to
bypass the IOAPIC when it is disabled and the local APIC is in virtual
wire mode. This is how the system is supposed to start, and can later be
switched into symmetric multiprocessing mode later on by an SMP aware OS
(most of them). Only the BSP should have it's LINT0 pin connected to the
I8259, since I8259 type interrupts are only usable by a single CPU at a
time.
Change-Id: I0e3e3338f14d384c26da660cf54779579eb0d641
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55696
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
In a real system, once a CPU receives an interrupt of type ExtInt, it
will send an INTA message out to the I8259 sytle interrupt controllers
to read the vector for that interrupt. In ye-olden-times, that would
literally mean the I8259 would be in charge of the bus and would write
the eight bit vector for the CPU to read. In more modern systems, the
vector is transported on the system interconnect using a special
message.
To better approximate a real system, and to make the interrupt
controllers more modular and agnostic (so the IO APIC doesn't have a
I8259 pointer within it, for instance), this change adds a new special
address which the I8259 can respond to on reads which will act as if it
received an INTA message, and the read data will be the interrupt
vector.
Only the master controller, or a single device, will respond to this
address, and because of its value and the fact that it's beyond the end
of the 16 bit IO port address space's effective range but still within
it, that address won't be generated by any other activity other than
possibly a bogus address.
Also by putting the special address in the IO port address space, that
will make it easier to ensure that it's within the range of addresses
which are routed towards the I8259 which operates off the IO port bus.
This address is not yet actually used by the IO APIC or local APIC but
will be shortly.
Change-Id: Ib73ab4ee08531028d3540570594c552f39053a40
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55694
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
These are no longer split out and shared in the root build/ directory.
This does result in a small amount of overhead from building redundant
copies of these files, although the overhead is not significant. When
building 7 different variants of gem5, all the ISAs and NULL, the
difference on my machine was:
Before:
real 41m25.372s
user 914m22.266s
sys 41m51.816s
After:
real 42m38.074s
user 921m36.852s
sys 43m2.949s
This is about a 2-3% difference, which is a worse than typical case,
since the overhead scales with the number of variants being built.
The benefit of pulling ext/ into the variant directory is that there can
now be a single config which applies to all files used to build gem5,
and that config is represented by the variant of gem5 being built.
Change-Id: I6f0db97c63a7f3e252e7e351aa862340978e701b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56750
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
The PC value is put in t7, but for that to be consistent with the way
microcode usually sees and interacts with the PC, it needs to have the
CS base value subtracted from it first. Otherwise the base could be
added into new PC values twice.
Change-Id: I8a8c5bc1befd9a89e6735981fd2fc69a702fdc68
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55690
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
The x86 version is basically just a specialization of the base IO port
version of the QEMU firmware configuration device, with the port
addresses set for x86.
The E820 entry type is x86 specific, and is a way to pass an E820 memory
map to firmware which doesn't have another way to figure out where
memory is. This would be for firmware like SeaBIOS which is itself
responsible for publishing an E820 map, but it needs somewhere to get
that information from in the first place. This mechanism is one it
supports natively.
This entry type reuses the E820Entry SimObjects which were defined a
long time ago for passing to a Linux FS workload. It doesn't use their
ability to write themselves out to guest memory, and just uses them as a
transport for their address, size and type properties.
Change-Id: Ifff214f5fc10bd7d0a2a0acddad4fc00dd65f67d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55628
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Previously, all abstract memory backed by the same physical memory will
use the exact same chunk of shared memory if sharedBackstore is set. It
means that all abstract memories, despite setting to a different range,
will still be map to the same chunk of memory.
As a result, setting the sharedBackstore not only allows our host system
to share gem5 memory, it also enforces multiple gem5 memories to share
the same content. Which will significantly affect the simulation result.
Furthermore, the actual size of the shared memory will be determined by
the last backingStore created. If the last one is unfortunately smaller
than any previous backingStore, this may invalid previous mapped region
and cause a SIGBUS upon access (on linux).
In this CL, we put all backingStores of those abstract memories side by
side instead of stacking them all together. So the behavior of abstract
memories will be kept consistent whether the sharedBackstore is set or
not, yet presist the ability to access those memories from host.
Change-Id: Ic4ec25c99fe72744afaa2dfbb48cd0d65230e9a8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57369
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
It's possible to bridge together the memory interconnect of two
systems, either as parallel peers, or one nested inside the other. Each
System will have its own set of RequestorIDs, and using an ID from one
System inside the other can lead to a number of different problems.
This change adds a new SimObject called SysBridge which connects two
Systems interconnect together. The object allocates a requestor ID in
each system, and for all PacketPtrs passing through it, the requestor
ID from the target system is installed in the associated Request. On
the way back, either inline or in a split, delayed response, the
original RequestorID is restored by reinstalling the original Request
object.
Change-Id: I237c668962a04ef6dfc872df16762a884c05ede9
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/54743
Reviewed-by: Jesse Pai <jessepai@google.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
"resources.json" is referenced when a resource is requested. The
"resources.json" file may be updated at any time and therefore, the
downloader was engineered to retrieve this file from the gem5-resources
repo on each request. However, this can lead to excessively frequently
pulls over short periods of time which is uncessary given how
infrequently this file changes.
To combat this, this patch caches the "resources.json" file and will
use it for up to an hour after creation before re-retrieving it.
Change-Id: I3b4907cbadce8a54df21d85f8021bf3603ae0f6f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57275
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
On occasion HTTP status codes, such as 429, are returned when
downloading the resources and/or the "resources.json" file. In such
cases it makes sense to retry the download.
This patch adds a Truncated Exponential Backoff algorithm to the
downloader to retry downloads, with a default maximum of 6 attempts.
This is done in cases where HTTP status codes 408, 429, and 5xx are
returned.
So this feature is applied to both the retrieval of the resources and
the "resource.json" file, the downloading of the "resources.json" file
has been modified to utilize the `_download` function as is used to
download resources
Change-Id: Ic4444b52f0f71d294fccec9de3140beece5f7576
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57274
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
We are introducing the MISCREG_TLBINEEDSYNC misc register to track
the presence of a pending DVM (TLBI) operation.
It will be used by:
* TLBI instructions: setting up the flag to indicate there
is a pending DVM message
* DSB instruction: clearing the flag indicating the DVM
messgage has been syncronized
Change-Id: I7a599ada5a6ac6f86ed2260caa872f085c889ab5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56601
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
These correspond to the existing operand types like IntRegOperand, or as
it's called in the operand table 'IntReg'. These subclasses
automatically set the base type name ('IntReg' for IntRegOperands),
which results in some mildly more familiar looking syntax, but is still
not that different from what we have today.
Change-Id: Id77c4e5a5e1b93c10aa9ad85e1a615f6c145832a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/49725
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Currently, to specify operands for an ISA, you define a dict from
operand names to properties in the ISA description. The properties are
in a list which has well defined positions for each entry, some of which
are optional.
These lists are fairly opaque since they don't have any way to, for
instance, accept keyword arguments. Also, these specifications simply
list as their first element what type of operand they're going to be.
This change is the first step in turning these specifications into
something more robust like a small temporary object. This object can be
constructed from a class which has a proper constructor that can take
keyword arguments, can have defaults, and can be subclassed.
Change-Id: I5f24d0b41f3e30b24a1ddd10157965d700d6c906
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/49724
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This artificial device is provided by QEMU inside their emulated
machines to feed extra configuration information to the system firmware,
or even to the operating system if it chose to use it. The behavior of
this device is explained in the docs/specs/fw_cfg.txt file in the QEMU
source.
This implementation currently supports the traditional interface, and
does not support the DMA based interface, although it probably wouldn't
be that hard to expand it to in the future.
The interface exposes individual entries which can optionally (and
usually) have paths associated with them that you can look up in a
directory type entry which has a fixed index. There are some entries
which are built into the device itself, which are the ID, signature and
directory entries, but the rest can be set up in the config scripts.
To make it easier to add new entries which are not from config scripts,
aka the ones that are hard coded in C++ and built into the device, the
actual entries themselves are not SimObjects, but it's easy to create a
SimObject wrapper which will spit them out for the device to consume.
Other items can be added to the device manually without generating them
with SimObjects.
Entries can have fixed or automatically generated indices. All entries
have a "path" in the sense that they have a name, but as a minor
deviation from what the QEMU documentation says, a "path" which begins
with a "." is not exported in the directory. This is purposefully
reminiscent of the unix style hidden file mechanism, where files or
directories who's names begin with "." are not normally shown by ls.
There are two different styles of this device, one which is IO port
based, and one which is MMIO based. Which to use depends on the
architecture, where x86 currently uses the IO scheme and ARM uses the
MMIO scheme. The documentation doesn't say what other ISAs use, if any
other ones support this interface, but I'd assume the MMIO version.
These are split out because the rules for how they work are subtly
different, but they share a lot of common machinery under the hood.
In most cases where somebody tries to talk to the device in an unusual
way, for instance accessing a register with an incomplete width or at an
offset, the device will just report all zeroes. The behavior in those
cases isn't specified, in many cases doesn't make sense based on the
design of the device, and doesn't seem to be depended on in the limited
use case I looked at.
Change-Id: Ib81ace406f877b298b9b98883d417e7d673916b5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55627
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
This is a far call direct, which has a far pointer (a 16 bit segment
selector and a 16 or 32 bit offset) as an immediate value. The gem5
decoder was expecting no immediate, and so was not gathering one. The
actual microcode for the instruction was taking the junk immediate and
trying to use it which did not work.
This change makes a small update to the table which says how big the
immediate values are for various instructions, changing the entry for
one byte opcode 0x9a from 0 (no immediate) to PO (pointer sized). The
immediate size will be automatically selected by the decoder based on
the PO rule, and the currently active operand size.
Change-Id: Ic290e7bb01dc6165c4eabed214887e4b5adb42da
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55626
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
For all instructions which affect the RIP, they are supposed to
truncate/zero extend the RIP based on the width of the instruction. We
should do that after the target is calculated by adding the two operands
together, but before adding in the segment base address.
Change-Id: I105e58de6a07c7aa3155a9a188d8877c2955651f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55592
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
