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This patch takes a first step in tightening up how we use the data
pointer in write packets. A const getter is added for the pointer
itself (getConstPtr), and a number of member functions are also made
const accordingly. In a range of places throughout the memory system
the new member is used.
The patch also removes the unused isReadWrite function.
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This patch removes the parameter that enables bypassing the null check
in the Packet::getPtr method. A number of call sites assume the value
to be non-null.
The one odd case is the RubyTester, which issues zero-sized
prefetches(!), and despite being reads they had no valid data
pointer. This is now fixed, but the size oddity remains (unless anyone
object or has any good suggestions).
Finally, in the Ruby Sequencer, appropriate checks are made for flush
packets as they have no valid data pointer.
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This patch adds a first cut GDDR5 config to accommodate the users
combining gem5 and GPUSim. The config is based on a SK Hynix
datasheet, and the Nvidia GTX580 specification. Someone from the
GPUSim user-camp should tweak the default page-policy and static
frontend and backend latencies.
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Mostly addressing uninitialised members.
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This patch adds uncacheable/cacheable and read-only/read-write attributes to
the map method of PageTableBase. It also modifies the constructor of TlbEntry
structs for all architectures to consider the new attributes.
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The multi level page table was giving false positives for already mapped
translations. This patch fixes the bogus behavior.
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Trimmed down all the lines greater than 78 characters.
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This patch sets up low and high privilege code and data segments and places them
in the following order: cs low, ds low, ds, cs, in the GDT. Additionally, a
syscall and page fault handler for KvmCPU in SE mode are defined. The order of
the segment selectors in GDT is required in this manner for interrupt handling
to work properly. Segment initialization is done for all the thread
contexts.
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This patch adds methods in KvmCPU model to handle KVM exits caused by syscall
instructions and page faults. These types of exits will be encountered if
KvmCPU is run in SE mode.
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Adding more features in the CPUid with the purpose of supporting running the
KvmCPU in SE mode.
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There was already a stub device at 0x80, the port traditionally used for an IO
delay. 0x80 is also the port used for POST codes sent by firmware, and that
may have prompted adding this port as a second option.
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The data size used for actually writing the base value for the segment was the
default size, but really it should set the entire value without any possible
truncation.
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The far pointer should be shifted right to get the selector value, not left.
Also, when calculating the width of the offset, the wrong register was used in
one spot.
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Otherwise the IPI which isn't sent will never arrive, and the deliveryStatus
bit will never be cleared.
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The getRegArrayBit function extracts a bit from a series of registers which
are treated as a single large bit array. A previous change had modified the
logic which figured out which bit to extract from ">> 5" to "% 5" which seems
wrong, especially when other, similar functions were changed to use "% 32".
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The value in EAX has an 8 bit field for the linear address size and one for
the physical address size when calling that function. A recent change
implemented it but returned 0xff for both of those fields. That implies that
linear and physical addresses are 255 bits wide which is wrong. When using the
KVM CPU model this causes an error, presumably because some of those bits are
actually reserved, or the CPU or kernel realizes 255 bits is a bad value.
This change makes those values 48.
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Another churn to clean up undefined behaviour, mostly ARM, but some
parts also touching the generic part of the code base.
Most of the fixes are simply ensuring that proper intialisation. One
of the more subtle changes is the return type of the sign-extension,
which is changed to uint64_t. This is to avoid shifting negative
values (undefined behaviour) in the ISA code.
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With recent changes OSX clang compilation fails due to an unused variable.
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This patch fixes a number of occurences where the sorting order of the
objects was implementation defined.
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This patch reverts changeset 9277177eccff which does not do what it
was intended to do. In essence, we go back to implementing mkutctime
much like the non-standard timegm extension.
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Mwait works as follows:
1. A cpu monitors an address of interest (monitor instruction)
2. A cpu calls mwait - this loads the cache line into that cpu's cache.
3. The cpu goes to sleep.
4. When another processor requests write permission for the line, it is
evicted from the sleeping cpu's cache. This eviction is forwarded to the
sleeping cpu, which then wakes up.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
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Fixes a bug where Minor drains in the midst of committing a
conditional store.
While committing a conditional store, lastCommitWasEndOfMacroop is true
(from the previous instruction) as we still haven't finished the conditional
store. If a drain occurs before the cache response, Minor would check just
lastCommitWasEndOfMacroop, which was true, and set drainState=DrainHaltFetch,
which increases the streamSeqNum. This caused the conditional store to be
squashed when the memory responded and it completed. However, to the memory
the store succeeded, while to the instruction sequence it never occurred.
In the case of an LLSC, the instruction sequence will replay the squashed
STREX, which will fail as the cache is no longer in LLSC. Then the
instruction sequence will loop back to a LDREX, which receives the updated
(incorrect) value.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
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Ruby's functional accesses are not guaranteed to succeed as of now. While
this is not a problem for the protocols that are currently in the mainline
repo, it seems that coherence protocols for gpus rely on a backing store to
supply the correct data. The aim of this patch is to make this backing store
configurable i.e. it comes into play only when a particular option:
--access-backing-store is invoked.
The backing store has been there since M5 and GEMS were integrated. The only
difference is that earlier the system used to maintain the backing store and
ruby's copy was write-only. Sometime last year, we moved to data being
supplied supplied by ruby in SE mode simulations. And now we have patches on
the reviewboard, which remove ruby's copy of memory altogether and rely
completely on the system's memory to supply data. This patch adds back a
SimpleMemory member to RubySystem. This member is used only if the option:
access-backing-store is set to true. By default, the memory would not be
accessed.
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This patch is the final in the series. The whole series and this patch in
particular were written with the aim of interfacing ruby's directory controller
with the memory controller in the classic memory system. This is being done
since ruby's memory controller has not being kept up to date with the changes
going on in DRAMs. Classic's memory controller is more up to date and
supports multiple different types of DRAM. This also brings classic and
ruby ever more close. The patch also changes ruby's memory controller to
expose the same interface.
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This function was added when I had incorrectly arrived at the conclusion
that such a function can improve the chances of a functional read succeeding.
As was later realized, this is not possible in the current setup. While the
code using this function was dropped long back, this function was not. Hence
the patch.
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This patch removes the data block present in the directory entry structure
of each protocol in gem5's mainline. Firstly, this is required for moving
towards common set of memory controllers for classic and ruby memory systems.
Secondly, the data block was being misused in several places. It was being
used for having free access to the physical memory instead of calling on the
memory controller.
From now on, the directory controller will not have a direct visibility into
the physical memory. The Memory Vector object now resides in the
Memory Controller class. This also means that some significant changes are
being made to the functional accesses in ruby.
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In my opinion, it creates needless complications in rest of the code.
Also, this structure hinders the move towards common set of code for
physical memory controllers.
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Both ruby and the system used to maintain memory copies. With the changes
carried for programmed io accesses, only one single memory is required for
fs simulations. This patch sets the copy of memory that used to reside
with the system to null, so that no space is allocated, but address checks
can still be carried out. All the memory accesses now source and sink values
to the memory maintained by ruby.
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As of now DMASequencer inherits from the RubyPort class. But the code in
RubyPort class is heavily tailored for the CPU Sequencer. There are parts of
the code that are not required at all for the DMA sequencer. Moreover, the
next patch uses the dma sequencer for carrying out memory accesses for all the
io devices. Hence, it is better to have a leaner dma sequencer.
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regressions.
This changes the default ARM system to a Versatile Express-like system that supports
2GB of memory and PCI devices and updates the default kernels/file-systems for
AArch64 ARM systems (64-bit) to support up to 32GB of memory and PCI devices. Some
platforms that are no longer supported have been pruned from the configuration files.
In addition a set of 64-bit ARM regressions have been added to the regression system.
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It is possible for the O3 CPU to consider itself drained and
later have a squashed instruction perform a writeback. This
patch re-adds tracking of in-flight instructions to prevent
falsely signaling a drained event.
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IEW did not check the instQueue and memDepUnit to ensure
they were drained. This caused issues when drainSanityCheck()
did check those structures after asserting IEW was drained.
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Automatically extract cpu release address from DTB file.
Check SCTLR_EL1 to verify all caches are enabled.
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The checker can't verify timer registers, so it should just grab the version
from the executing CPU, otherwise it could get a larger value and diverge
execution.
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The checker didn't know how to properly validate these new commands.
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This patch fixes a bug where a completing load or store which is also a
barrier can push a barrier into the store buffer without first checking
that there is a free slot.
The bug was not fatal but would print a warning that the store buffer
was full when inserting.
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WriteInvalidate semantics depend on the unconditional writeback
or they won't complete. Also, there's no point in deferring snoops
on their MSHRs, as they don't get new data at the end of their life
cycle the way other transactions do.
Add comment in the cache about a minor inefficiency re: WriteInvalidate.
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Since WriteInvalidate directly writes into the cache, it can
create tricky timing interleavings with reads and writes to the
same cache line that haven't yet completed. This patch ensures
that these requests, when completed, don't overwrite the newer
data from the WriteInvalidate.
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This hook allows blocking emulated system calls to indicate
that they would block, but return control to the simulator
so that the simulation does not hang. The actual retry
functionality requires additional support, to be provided
in a future changeset.
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Not clear why they were marked virtual to begin with,
but that doesn't appear to be necessary.
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Move the BufferArg classes that support syscall buffer args
(i.e., pointers into simulated user space) out of syscall_emul.hh
and into a new header syscall_emul_buf.hh so they are accessible
to emulated driver implementations.
Take the opportunity to add some comments as well.
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Fake SE-mode device drivers can now be added by
deriving from this abstract object.
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