When implementing timing address translations instead of atomic, I
forgot to preserve the faults that are returned from the read and
write calls. This patch reinstates them.
When each load or store is sent to the LSQ, we check whether it will cross a
cache line boundary and, if so, split it in two. This creates two TLB
translations and two memory requests. Care has to be taken if the first
packet of a split load is sent but the second blocks the cache. Similarly,
for a store, if the first packet cannot be sent, we must store the second
one somewhere to retry later.
This modifies the LSQSenderState class to record both packets in a split
load or store.
Finally, a new const variable, HasUnalignedMemAcc, is added to each ISA
to indicate whether unaligned memory accesses are allowed. This is used
throughout the changed code so that compiler can optimise away code dealing
with split requests for ISAs that don't need them.
This initiates a timing translation and passes the read or write on to the
processor before waiting for it to finish. Once the translation is finished,
the instruction's state is updated via the 'finish' function. A new
DataTranslation class is created to handle this.
The idea is taken from the implementation of timing translations in
TimingSimpleCPU by Gabe Black. This patch also separates out the timing
translations from this CPU and uses the new DataTranslation class.
- on certain retry requests you can get an assertion failure
- fix by allowing the request to literally "Retry" itself
if it wasnt successful before, and then block any requests
through cache port while waiting for the cache to be
made available for access
when threads are switching in/out the CPU, we need to keep
track of special cases like branches. Add appropriate
variables in ThreadState t track this and then use
these variables when updating pc after context switch
this will be used for when a thread comes back from a cache miss, it needs to update the PCs
because the inst might of been a branch or delayslot in which the next PC isnt always
a straight addition
allow a thread to wakeup and be activated after
it has been in suspended state and another
thread is switched out. Need to give
pipeline stages a "activateThread" function
so that can get to their suspended instruction
when the time is right.
give resources their own specific
activity to do for a "suspend" event
instead of defaulting to deactivating the thread for a
suspend thread event. This really matters
for the fetch sequence unit which wants to remove the
thread from fetching while other units want to
ignore a thread suspension. If you deactivate a thread
in a resource then you may lose some of the allotted
bandwidth that the thread is taking up...
update/add in the use of isThreadReady & isThreadSuspended
functions.Check in activateThread what list a thread is
on so it can be managed accordingly.
-Support ability to activate next ready thread after a cache miss
through the activateNextReadyContext/Thread() functions
-To support this a "readyList" of thread ids is added
-After a cache miss, thread will suspend and then call
activitynextreadythread
allow for events to schedule themselves later if desired. this is important
because of cases like where you need to activate a thread only after the previous
thread has been deactivated. The ordering there has to be enforced
add code to recognize memory stalls in resources and the pipeline as well
as squash a thread if there is a stall and we are in the switch on cache miss
model
add buffer for instructions to switch out to in a pipeline stage
can't squash the instruction and remove the pipeline so we kind of need
to 'suspend' an instruction at the stage while the memory stall resolves
for the switch on cache miss model
- loads were happening on same cycle as the address was generated which is slightly
unrealistic. Instead, force address generation to be on separate cycle from load
initiation
- also, mark the stages in a more traditional way (F-D-X-M-W)
This adds support for the 32-bit, big endian Power ISA. This supports both
integer and floating point instructions based on the Power ISA Book I v2.06.
When enabled, faulting instructions appear in the trace twice
(once when they fault and again when they're re-executed).
This flag is set by the Exec compound flag for backwards compatibility.
Get rid of misc.py and just stick misc things in __init__.py
Move utility functions out of SCons files and into m5.util
Move utility type stuff from m5/__init__.py to m5/util/__init__.py
Remove buildEnv from m5 and allow access only from m5.defines
Rename AddToPath to addToPath while we're moving it to m5.util
Rename read_command to readCommand while we're moving it
Rename compare_versions to compareVersions while we're moving it.
--HG--
rename : src/python/m5/convert.py => src/python/m5/util/convert.py
rename : src/python/m5/smartdict.py => src/python/m5/util/smartdict.py
TLBUnit no longer used and we also get rid of memAccSize and memAccFlags functions added to ISA and StaticInst
since TLB is not a separate resource to acquire. Instead, TLB access is done before any read/write to memory
and the result is checked before it's sent out to memory.
* * *
inorder was incorrectly storing FP values and confusing the integer/fp storage view of floating point operations. A big issue was knowing trying to infer when were doing single or double precision access
because this lets you know the size of value to store (32-64 bits). This isnt exactly straightforward since alpha uses all 64-bit regs while mips/sparc uses a dual-reg view. by getting this value from
the actual floating point register file, the model can figure out what it needs to store
Remove subinstructions eaComp/memAcc since unused in CPU Models. Instead, create eaComp that is visible from StaticInst object. Gives InOrder model capability of generating address without actually initiating access
* * *
Changes so that InOrder can work for a non-delay-slot ISA like Alpha. Typically, changes have to do with handling misspeculated branches at different points in pipeline
Edit AlphaISA to support the inorder model. Mostly alternate constructor functions and also a few skeleton multithreaded support functions
* * *
Remove namespace from header file. Causes compiler issues that are hard to find
* * *
Separate the TLB from the CPU and allow it to live in the TLBUnit resource. Give CPU accessor functions for access and also bind at construction time
* * *
Expose memory access size and flags through instruction object
(temporarily memAccSize and memFlags to get TLB stuff working.)
this was double scheduling itself (once in constructor and once in cpu code). also add support for stopping / starting
progress events through repeatEvent flag and also changing the interval of the progress event as well
