Commit graph

77 commits

Author SHA1 Message Date
Steve Reinhardt
6f1187943c Replace curTick global variable with accessor functions.
This step makes it easy to replace the accessor functions
(which still access a global variable) with ones that access
per-thread curTick values.
2011-01-07 21:50:29 -08:00
Ali Saidi
cdacbe734a ARM/Alpha/Cpu: Change prefetchs to be more like normal loads.
This change modifies the way prefetches work. They are now like normal loads
that don't writeback a register. Previously prefetches were supposed to call
prefetch() on the exection context, so they executed with execute() methods
instead of initiateAcc() completeAcc(). The prefetch() methods for all the CPUs
are blank, meaning that they get executed, but don't actually do anything.

On Alpha dead cache copy code was removed and prefetches are now normal ops.
They count as executed operations, but still don't do anything and IsMemRef is
not longer set on them.

On ARM IsDataPrefetch or IsInstructionPreftech is now set on all prefetch
instructions. The timing simple CPU doesn't try to do anything special for
prefetches now and they execute with the normal memory code path.
2010-11-08 13:58:22 -06:00
Gabe Black
6f4bd2c1da ISA,CPU,etc: Create an ISA defined PC type that abstracts out ISA behaviors.
This change is a low level and pervasive reorganization of how PCs are managed
in M5. Back when Alpha was the only ISA, there were only 2 PCs to worry about,
the PC and the NPC, and the lsb of the PC signaled whether or not you were in
PAL mode. As other ISAs were added, we had to add an NNPC, micro PC and next
micropc, x86 and ARM introduced variable length instruction sets, and ARM
started to keep track of mode bits in the PC. Each CPU model handled PCs in
its own custom way that needed to be updated individually to handle the new
dimensions of variability, or, in the case of ARMs mode-bit-in-the-pc hack,
the complexity could be hidden in the ISA at the ISA implementation's expense.
Areas like the branch predictor hadn't been updated to handle branch delay
slots or micropcs, and it turns out that had introduced a significant (10s of
percent) performance bug in SPARC and to a lesser extend MIPS. Rather than
perpetuate the problem by reworking O3 again to handle the PC features needed
by x86, this change was introduced to rework PC handling in a more modular,
transparent, and hopefully efficient way.


PC type:

Rather than having the superset of all possible elements of PC state declared
in each of the CPU models, each ISA defines its own PCState type which has
exactly the elements it needs. A cross product of canned PCState classes are
defined in the new "generic" ISA directory for ISAs with/without delay slots
and microcode. These are either typedef-ed or subclassed by each ISA. To read
or write this structure through a *Context, you use the new pcState() accessor
which reads or writes depending on whether it has an argument. If you just
want the address of the current or next instruction or the current micro PC,
you can get those through read-only accessors on either the PCState type or
the *Contexts. These are instAddr(), nextInstAddr(), and microPC(). Note the
move away from readPC. That name is ambiguous since it's not clear whether or
not it should be the actual address to fetch from, or if it should have extra
bits in it like the PAL mode bit. Each class is free to define its own
functions to get at whatever values it needs however it needs to to be used in
ISA specific code. Eventually Alpha's PAL mode bit could be moved out of the
PC and into a separate field like ARM.

These types can be reset to a particular pc (where npc = pc +
sizeof(MachInst), nnpc = npc + sizeof(MachInst), upc = 0, nupc = 1 as
appropriate), printed, serialized, and compared. There is a branching()
function which encapsulates code in the CPU models that checked if an
instruction branched or not. Exactly what that means in the context of branch
delay slots which can skip an instruction when not taken is ambiguous, and
ideally this function and its uses can be eliminated. PCStates also generally
know how to advance themselves in various ways depending on if they point at
an instruction, a microop, or the last microop of a macroop. More on that
later.

Ideally, accessing all the PCs at once when setting them will improve
performance of M5 even though more data needs to be moved around. This is
because often all the PCs need to be manipulated together, and by getting them
all at once you avoid multiple function calls. Also, the PCs of a particular
thread will have spatial locality in the cache. Previously they were grouped
by element in arrays which spread out accesses.


Advancing the PC:

The PCs were previously managed entirely by the CPU which had to know about PC
semantics, try to figure out which dimension to increment the PC in, what to
set NPC/NNPC, etc. These decisions are best left to the ISA in conjunction
with the PC type itself. Because most of the information about how to
increment the PC (mainly what type of instruction it refers to) is contained
in the instruction object, a new advancePC virtual function was added to the
StaticInst class. Subclasses provide an implementation that moves around the
right element of the PC with a minimal amount of decision making. In ISAs like
Alpha, the instructions always simply assign NPC to PC without having to worry
about micropcs, nnpcs, etc. The added cost of a virtual function call should
be outweighed by not having to figure out as much about what to do with the
PCs and mucking around with the extra elements.

One drawback of making the StaticInsts advance the PC is that you have to
actually have one to advance the PC. This would, superficially, seem to
require decoding an instruction before fetch could advance. This is, as far as
I can tell, realistic. fetch would advance through memory addresses, not PCs,
perhaps predicting new memory addresses using existing ones. More
sophisticated decisions about control flow would be made later on, after the
instruction was decoded, and handed back to fetch. If branching needs to
happen, some amount of decoding needs to happen to see that it's a branch,
what the target is, etc. This could get a little more complicated if that gets
done by the predecoder, but I'm choosing to ignore that for now.


Variable length instructions:

To handle variable length instructions in x86 and ARM, the predecoder now
takes in the current PC by reference to the getExtMachInst function. It can
modify the PC however it needs to (by setting NPC to be the PC + instruction
length, for instance). This could be improved since the CPU doesn't know if
the PC was modified and always has to write it back.


ISA parser:

To support the new API, all PC related operand types were removed from the
parser and replaced with a PCState type. There are two warts on this
implementation. First, as with all the other operand types, the PCState still
has to have a valid operand type even though it doesn't use it. Second, using
syntax like PCS.npc(target) doesn't work for two reasons, this looks like the
syntax for operand type overriding, and the parser can't figure out if you're
reading or writing. Instructions that use the PCS operand (which I've
consistently called it) need to first read it into a local variable,
manipulate it, and then write it back out.


Return address stack:

The return address stack needed a little extra help because, in the presence
of branch delay slots, it has to merge together elements of the return PC and
the call PC. To handle that, a buildRetPC utility function was added. There
are basically only two versions in all the ISAs, but it didn't seem short
enough to put into the generic ISA directory. Also, the branch predictor code
in O3 and InOrder were adjusted so that they always store the PC of the actual
call instruction in the RAS, not the next PC. If the call instruction is a
microop, the next PC refers to the next microop in the same macroop which is
probably not desirable. The buildRetPC function advances the PC intelligently
to the next macroop (in an ISA specific way) so that that case works.


Change in stats:

There were no change in stats except in MIPS and SPARC in the O3 model. MIPS
runs in about 9% fewer ticks. SPARC runs with 30%-50% fewer ticks, which could
likely be improved further by setting call/return instruction flags and taking
advantage of the RAS.


TODO:

Add != operators to the PCState classes, defined trivially to be !(a==b).
Smooth out places where PCs are split apart, passed around, and put back
together later. I think this might happen in SPARC's fault code. Add ISA
specific constructors that allow setting PC elements without calling a bunch
of accessors. Try to eliminate the need for the branching() function. Factor
out Alpha's PAL mode pc bit into a separate flag field, and eliminate places
where it's blindly masked out or tested in the PC.
2010-10-31 00:07:20 -07:00
Gabe Black
8f3fbd2d13 CPU: Get rid of the now unnecessary getInst/setInst family of functions.
This code is no longer needed because of the preceeding change which adds a
StaticInstPtr parameter to the fault's invoke method, obviating the only use
for this pair of functions.
2010-09-13 21:58:34 -07:00
Gabe Black
6833ca7eed Faults: Pass the StaticInst involved, if any, to a Fault's invoke method.
Also move the "Fault" reference counted pointer type into a separate file,
sim/fault.hh. It would be better to name this less similarly to sim/faults.hh
to reduce confusion, but fault.hh matches the name of the type. We could change
Fault to FaultPtr to match other pointer types, and then changing the name of
the file would make more sense.
2010-09-13 19:26:03 -07:00
Gabe Black
c9d01c6557 CPU: Get rid of the unused ev5_trap function on the simple and checker CPUs. 2010-08-31 09:47:29 -07:00
Steve Reinhardt
f92e91e853 Minor remote GDB cleanup.
Expand the help text on the --remote-gdb-port option so
people know you can use it to disable remote gdb without
reading the source code, and thus don't waste any time
trying to add a separate option to do that.
Clean up some gdb-related cruft I found while looking
for where one would add a gdb disable option, before
I found the comment that told me that I didn't need
to do that.
2010-06-03 16:54:26 -07:00
Nathan Binkert
f0b4259e98 cpu_models: get rid of cpu_models.py and move the stuff into SCons 2010-02-26 18:14:48 -08:00
Gabe Black
b8120f6c38 Mem: Eliminate the NO_FAULT request flag. 2009-11-10 21:10:18 -08:00
Nathan Binkert
d9f39c8ce7 arch: nuke arch/isa_specific.hh and move stuff to generated config/the_isa.hh 2009-09-23 08:34:21 -07:00
Gabe Black
c9a27d85b9 Get rid of the unused get(Data|Inst)Asid and (inst|data)Asid functions. 2009-07-08 23:02:22 -07:00
Gabe Black
25884a8773 Registers: Get rid of the float register width parameter. 2009-07-08 23:02:20 -07:00
Gabe Black
bd6f2bb538 Mem: Change isLlsc to isLLSC. 2009-04-19 21:44:15 -07:00
Gabe Black
3e5f487663 Memory: Rename LOCKED for load locked store conditional to LLSC. 2009-04-19 04:25:01 -07:00
Steve Reinhardt
7617dcf736 ThreadState: initialize status to Halted in constructor.
This provides a common initial status for all threads independent
of CPU model (unlike the prior situation where CPUs initialized
threads to inconsistent states).
This mostly matters for SE mode; in FS mode, ISA-specific startupCPU()
methods generally handle boot-time initialization of thread contexts
(since the right thing to do is ISA-dependent).
2009-04-15 13:18:24 -07:00
Steve Reinhardt
8882dc1283 Get rid of the Unallocated thread context state.
Basically merge it in with Halted.
Also had to get rid of a few other functions that
called ThreadContext::deallocate(), including:
 - InOrderCPU's setThreadRescheduleCondition.
 - ThreadContext::exit().  This function was there to avoid terminating
   simulation when one thread out of a multi-thread workload exits, but we
   need to find a better (non-cpu-centric) way.
2009-04-15 13:13:47 -07:00
Gabe Black
7b5a96f06b tlb: Don't separate the TLB classes into an instruction TLB and a data TLB 2009-04-08 22:21:27 -07:00
Gabe Black
9a000c5173 Processes: Make getting and setting system call arguments part of a process object. 2009-02-27 09:22:14 -08:00
Gabe Black
5605079b1f ISA: Replace the translate functions in the TLBs with translateAtomic. 2009-02-25 10:15:44 -08:00
Gabe Black
a1aba01a02 CPU: Get rid of translate... functions from various interface classes. 2009-02-25 10:15:34 -08:00
Lisa Hsu
dd99ff23c6 get rid of all instances of readTid() and getThreadNum(). Unify and eliminate
redundancies with threadId() as their replacement.
2008-11-04 11:35:42 -05:00
Lisa Hsu
d857faf073 Add in Context IDs to the simulator. From now on, cpuId is almost never used,
the primary identifier for a hardware context should be contextId().  The
concept of threads within a CPU remains, in the form of threadId() because
sometimes you need to know which context within a cpu to manipulate.
2008-11-02 21:57:07 -05:00
Lisa Hsu
c55a467a06 make BaseCPU the provider of _cpuId, and cpuId() instead of being scattered
across the subclasses. generally make it so that member data is _cpuId and
accessor functions are cpuId(). The ID val comes from the python (default -1 if
none provided), and if it is -1, the index of cpuList will be given. this has
passed util/regress quick and se.py -n4 and fs.py -n4 as well as standard
switch.
2008-11-02 21:56:57 -05:00
Ali Saidi
b760b99f4d O3CPU: Undo Gabe's changes to remove hwrei and simpalcheck from O3 CPU. Removing hwrei causes
the instruction after the hwrei to be fetched before the ITB/DTB_CM register is updated in a call pal
call sys and thus the translation fails because the user is attempting to access a super page address.

Minimally, it seems as though some sort of fetch stall or refetch after a hwrei is required. I think
this works currently because the hwrei uses the exec context interface, and the o3 stalls when that occurs.

Additionally, these changes don't update the LOCK register and probably break ll/sc. Both o3 changes were
removed since a great deal of manual patching would be required to only remove the hwrei change.
2008-10-20 16:22:59 -04:00
Gabe Black
f245358343 Get rid of old RegContext code. 2008-10-12 17:57:46 -07:00
Gabe Black
f621b7b81f CPU: Eliminate the simPalCheck funciton. 2008-10-11 12:17:24 -07:00
Gabe Black
da7209ec93 CPU: Eliminate the hwrei function. 2008-10-11 02:27:21 -07:00
Ali Saidi
3a3e356f4e style: Remove non-leading tabs everywhere they shouldn't be. Developers should configure their editors to not insert tabs 2008-09-10 14:26:15 -04:00
Nathan Binkert
ee62a0fec8 params: Convert the CPU objects to use the auto generated param structs.
A whole bunch of stuff has been converted to use the new params stuff, but
the CPU wasn't one of them.  While we're at it, make some things a bit
more stylish. Most of the work was done by Gabe, I just cleaned stuff up
a bit more at the end.
2008-08-11 12:22:16 -07:00
Ali Saidi
a4a7a09e96 Remove delVirtPort() and make getVirtPort() only return cached version. 2008-07-01 10:25:07 -04:00
Gabe Black
8b4796a367 TLB: Make a TLB base class and put a virtual demapPage function in it.
--HG--
extra : convert_revision : cc0e62a5a337fd5bf332ad33bed61c0d505a936f
2008-02-26 23:38:51 -05:00
Gabe Black
537239b278 Address Translation: Make SE mode use an actual TLB/MMU for translation like FS.
--HG--
extra : convert_revision : a04a30df0b6246e877a1cea35420dbac94b506b1
2007-08-26 20:24:18 -07:00
Ali Saidi
689cab36c9 *MiscReg->*MiscRegNoEffect, *MiscRegWithEffect->*MiscReg
--HG--
extra : convert_revision : f799b65f1b2a6bf43605e6870b0f39b473dc492b
2007-03-07 15:04:31 -05:00
Ali Saidi
f72a999393 some forgotten commits
--HG--
extra : convert_revision : 213440066c700ed5891a6d4568928b7f3f2fe750
2007-02-12 18:40:08 -05:00
Steve Reinhardt
6c8c86f2f9 Rename the StaticInst-based (read|set)(Int|Float)Reg methods to (read|set)(Int|Float)RegOperand to distinguish from non-StaticInst version.
--HG--
extra : convert_revision : b33ce0ebe2fee86cc791c00a35d8c6e395e1380c
2006-12-12 09:58:40 -08:00
Gabe Black
c693c6ba9f Put kernel_stats back into arch.
--HG--
rename : src/kern/alpha/idle_event.cc => src/arch/alpha/idle_event.cc
rename : src/kern/alpha/idle_event.hh => src/arch/alpha/idle_event.hh
rename : src/kern/alpha/kernel_stats.cc => src/arch/alpha/kernel_stats.cc
rename : src/kern/alpha/kernel_stats.hh => src/arch/alpha/kernel_stats.hh
rename : src/kern/sparc/kernel_stats.hh => src/arch/sparc/kernel_stats.hh
rename : src/kern/base_kernel_stats.cc => src/kern/kernel_stats.cc
rename : src/kern/base_kernel_stats.hh => src/kern/kernel_stats.hh
extra : convert_revision : 42bd3e36b407edbd19b912c9218f4e5923a15966
2006-11-07 22:34:34 -05:00
Gabe Black
4bfb8547bb Moved the switched version of kernel_stats.hh back to kern, and moved the base kernel_stats to base_kernel_stats
--HG--
extra : convert_revision : 2a010d2eb7ea2586ff063b99b8bcde6eb1e8e017
2006-11-07 05:36:54 -05:00
Gabe Black
118b9dc1f9 Got rid of "inPalMode". Some places are still effectively checking if they are in PAL mode, however.
--HG--
extra : convert_revision : b52d9642efc474eaf97437fa2df879efefa0062b
2006-11-03 04:25:33 -05:00
Kevin Lim
e71ccde663 Merge ktlim@zizzer:/bk/newmem
into  zamp.eecs.umich.edu:/z/ktlim2/clean/newmem-busfix

--HG--
extra : convert_revision : a9a41e2c292bd95aa148e1cf4d9a77c0622a462b
2006-11-02 15:20:47 -05:00
Kevin Lim
ccaf80cc46 Use ISA specific makeExtMI.
src/arch/alpha/utility.hh:
    For now makeExtMI will be specific to the ISA.

--HG--
extra : convert_revision : 89959c6499efcc3df9301ad8ea039580764a1496
2006-11-02 13:11:38 -05:00
Gabe Black
b565660c42 Merge zizzer.eecs.umich.edu:/bk/newmem/
into  zeep.eecs.umich.edu:/home/gblack/m5/newmemmemops

--HG--
extra : convert_revision : c2f7398a0d14dd11108579bb243ada7420285a22
2006-11-01 19:00:59 -05:00
Gabe Black
2b11b47357 Adjustments for the AlphaTLB changing to AlphaISA::TLB and changing register file functions to not take faults
--HG--
extra : convert_revision : 1cef0734462ee2e4db12482462c2ab3c134d3675
2006-11-01 16:44:45 -05:00
Kevin Lim
bfd5eb2b08 Remove mem parameter. Now the translating port asks the CPU's dcache's peer for its MemObject instead of having to have a paramter for the MemObject.
configs/example/fs.py:
configs/example/se.py:
src/cpu/simple/base.cc:
src/cpu/simple/base.hh:
src/cpu/simple/timing.cc:
src/cpu/simple_thread.cc:
src/cpu/simple_thread.hh:
src/cpu/thread_state.cc:
src/cpu/thread_state.hh:
tests/configs/o3-timing-mp.py:
tests/configs/o3-timing.py:
tests/configs/simple-atomic-mp.py:
tests/configs/simple-atomic.py:
tests/configs/simple-timing-mp.py:
tests/configs/simple-timing.py:
tests/configs/tsunami-simple-atomic-dual.py:
tests/configs/tsunami-simple-atomic.py:
tests/configs/tsunami-simple-timing-dual.py:
tests/configs/tsunami-simple-timing.py:
    No need for mem parameter any more.
src/cpu/checker/cpu.cc:
    Use new constructor for simple thread (no more MemObject parameter).
src/cpu/checker/cpu.hh:
    Remove MemObject parameter.
src/cpu/memtest/memtest.hh:
    Ports now take in their MemObject owner.
src/cpu/o3/alpha/cpu_builder.cc:
    Remove mem parameter.
src/cpu/o3/alpha/cpu_impl.hh:
    Remove memory parameter and clean up handling of TranslatingPort.
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/mips/cpu_builder.cc:
src/cpu/o3/mips/cpu_impl.hh:
src/cpu/o3/params.hh:
src/cpu/o3/thread_state.hh:
src/cpu/ozone/cpu.hh:
src/cpu/ozone/cpu_builder.cc:
src/cpu/ozone/cpu_impl.hh:
src/cpu/ozone/front_end.hh:
src/cpu/ozone/front_end_impl.hh:
src/cpu/ozone/lw_lsq.hh:
src/cpu/ozone/lw_lsq_impl.hh:
src/cpu/ozone/simple_params.hh:
src/cpu/ozone/thread_state.hh:
src/cpu/simple/atomic.cc:
    Remove memory parameter.

--HG--
extra : convert_revision : 43cb44a33b31320d44b69679dcf646c0380d07d3
2006-10-31 14:33:56 -05:00
Gabe Black
038217049a Move IntrFlag into the MiscRegFile and get rid of specialized accessor functions.
--HG--
extra : convert_revision : e0d12a150b01d05de9bc02bcbc7c22797975a5b9
2006-10-31 03:37:01 -05:00
Gabe Black
0b5cf4ba6e Merge zizzer.eecs.umich.edu:/bk/newmem
into  zeep.eecs.umich.edu:/home/gblack/m5/newmem

--HG--
extra : convert_revision : 2711fec2bf72801999b060e65f0bf744c18734fb
2006-10-20 16:39:47 -04:00
Nathan Binkert
a4c6f0d69e Use PacketPtr everywhere
--HG--
extra : convert_revision : d9eb83ab77ffd2d725961f295b1733137e187711
2006-10-20 00:10:12 -07:00
Nathan Binkert
7245d4530d refactor code for the packet, get rid of packet_impl.hh
and call it packet_access.hh and fix the #includes so
things compile right.

--HG--
extra : convert_revision : d3626c9715b9f7e51bb3ab8d97e971fad4e0b724
2006-10-19 23:38:45 -07:00
Gabe Black
866cfaf9dc Merge zizzer.eecs.umich.edu:/bk/newmem
into  zeep.eecs.umich.edu:/home/gblack/m5/newmem

--HG--
extra : convert_revision : 30b2475ba034550376455e1bc0e52e19a200fd5a
2006-10-12 10:58:45 -04:00
Kevin Lim
bdde892d66 Merge ktlim@zizzer:/bk/newmem
into  zamp.eecs.umich.edu:/z/ktlim2/clean/o3-merge/newmem

src/cpu/memtest/memtest.cc:
src/cpu/memtest/memtest.hh:
src/cpu/simple/timing.hh:
tests/configs/o3-timing-mp.py:
    Hand merge.

--HG--
extra : convert_revision : a58cc439eb5e8f900d175ed8b5a85b6c8723e558
2006-10-09 22:59:56 -04:00
Kevin Lim
6a2d6c0f83 Fix checker bug.
src/cpu/checker/thread_context.hh:
    Checker's TC should only copy state, and not fully take over from the old context (prevents it from accidentally stealing the quiesce event).

--HG--
extra : convert_revision : 5760f9c5bae749f8d1df35e4c898df13e41b0224
2006-10-09 11:00:31 -04:00