Commit graph

71 commits

Author SHA1 Message Date
Gabe Black
40b6c9cb2e X86: Move the MSR lookup table out of the TLB and into its own file.
Translating MSR addresses into MSR register indices took a lot of space in the
TLB source and made looking around in that file awkward. This change moves
the lookup into its own file to get it out of the way. It also changes it from
a switch statement to a hash map which should hopefully be a little more
efficient.
2011-09-23 02:42:22 -07:00
Gabe Black
a1ad9e652a Stack: Tidy up some comments, a warning, and make stack extension consistent.
Do some minor cleanup of some recently added comments, a warning, and change
other instances of stack extension to be like what's now being done for x86.
2011-09-09 01:01:43 -07:00
Gabe Black
3bd0b9654c X86,TLB: Make sure the "delayedResponse" variable is always set.
When an instruction is translated in the x86 TLB, a variable called
delayedResponse is passed back and forth which tracks whether a translation
could be completed immediately, or if there's going to be callback that will
finish things up. If a read was to the internal memory space, memory mapped
registers used to implement things like MSRs, the function hadn't yet gotten
to where delayedResponse was set to false, it's default. That meant that the
value was never set, and the TLB could start waiting for a callback that would
never come. This change simply moves the assignment to above where control
can divert to translateInt().
2011-09-05 02:48:57 -07:00
Lisa Hsu
365966304e TLB: comments and a helpful warning.
Nothing big here, but when you have an address that is not in the page table request to be allocated, if it falls outside of the maximum stack range all you get is a page fault and you don't know why.  Add a little warn() to explain it a bit.  Also add some comments and alter logic a little so that you don't totally ignore the return value of checkAndAllocNextPage().
2011-09-02 17:04:00 -07:00
Nathan Binkert
eddac53ff6 trace: reimplement the DTRACE function so it doesn't use a vector
At the same time, rename the trace flags to debug flags since they
have broader usage than simply tracing.  This means that
--trace-flags is now --debug-flags and --trace-help is now --debug-help
2011-04-15 10:44:32 -07:00
Nathan Binkert
39a055645f includes: sort all includes 2011-04-15 10:44:06 -07:00
Gabe Black
579c5f0b65 Spelling: Fix the a spelling error by changing mmaped to mmapped.
There may not be a formally correct spelling for the past tense of mmap, but
mmapped is the spelling Google doesn't try to autocorrect. This makes sense
because it mirrors the past tense of map->mapped and not the past tense of
cape->caped.

--HG--
rename : src/arch/alpha/mmaped_ipr.hh => src/arch/alpha/mmapped_ipr.hh
rename : src/arch/arm/mmaped_ipr.hh => src/arch/arm/mmapped_ipr.hh
rename : src/arch/mips/mmaped_ipr.hh => src/arch/mips/mmapped_ipr.hh
rename : src/arch/power/mmaped_ipr.hh => src/arch/power/mmapped_ipr.hh
rename : src/arch/sparc/mmaped_ipr.hh => src/arch/sparc/mmapped_ipr.hh
rename : src/arch/x86/mmaped_ipr.hh => src/arch/x86/mmapped_ipr.hh
2011-03-01 23:18:47 -08:00
Gabe Black
d3214c5c5e X86: If PCI config space is disabled, pass through to regular IO addresses. 2011-02-27 16:25:06 -08:00
Tim Harris
44e5e7e053 X86: Obey the wp bit of CR0.
If cr0.wp ("write protect" bit) is clear then do not generate page faults when
writing to write-protected pages in kernel mode.
2011-02-07 15:18:52 -08:00
Joel Hestness
3a2d2223e1 x86: Timing support for pagetable walker
Move page table walker state to its own object type, and make the
walker instantiate state for each outstanding walk. By storing the
states in a queue, the walker is able to handle multiple outstanding
timing requests. Note that functional walks use separate state
elements.
2011-02-06 22:14:18 -08:00
Steve Reinhardt
c69d48f007 Make commenting on close namespace brackets consistent.
Ran all the source files through 'perl -pi' with this script:

s|\s*(};?\s*)?/\*\s*(end\s*)?namespace\s*(\S+)\s*\*/(\s*})?|} // namespace $3|;
s|\s*};?\s*//\s*(end\s*)?namespace\s*(\S+)\s*|} // namespace $2\n|;
s|\s*};?\s*//\s*(\S+)\s*namespace\s*|} // namespace $1\n|;

Also did a little manual editing on some of the arch/*/isa_traits.hh files
and src/SConscript.
2011-01-03 14:35:43 -08:00
Gabe Black
3cd349f443 X86: Obey the PCD (cache disable) bit in the page tables. 2010-11-23 06:10:17 -05:00
Gabe Black
c8c921b9db X86: Mark IO space accesses as uncachable. 2010-11-22 05:49:03 -05:00
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
25ffa8eb8b X86: Create a directory for files that define register indexes.
This is to help tidy up arch/x86. These files should not be used external to
the ISA.

--HG--
rename : src/arch/x86/apicregs.hh => src/arch/x86/regs/apic.hh
rename : src/arch/x86/floatregs.hh => src/arch/x86/regs/float.hh
rename : src/arch/x86/intregs.hh => src/arch/x86/regs/int.hh
rename : src/arch/x86/miscregs.hh => src/arch/x86/regs/misc.hh
rename : src/arch/x86/segmentregs.hh => src/arch/x86/regs/segment.hh
2010-08-23 16:14:24 -07:00
Gabe Black
f6182f948b X86: Make the TLB fault instead of panic when something is unmapped in SE mode.
The fault object, if invoked, would then panic. This is a bit less direct, but
it means speculative execution won't panic the simulator.
2010-08-23 09:44:19 -07:00
Nathan Binkert
13d64906c2 copyright: Change HP copyright on x86 code to be more friendly 2010-05-23 22:44:15 -07:00
Gabe Black
bbbfdee2ed X86: Don't panic on faults on prefetches in SE mode. 2009-11-08 22:49:58 -08:00
Gabe Black
44e912c6bd X86: Explain what really didn't work with unmapped addresses in SE mode. 2009-11-08 22:49:57 -08:00
Steve Reinhardt
1c28004654 Clean up some inconsistencies with Request flags. 2009-08-01 22:50:13 -07:00
Gabe Black
0cb180ea0d Registers: Eliminate the ISA defined floating point register file. 2009-07-08 23:02:20 -07:00
Gabe Black
32daf6fc3f Registers: Add an ISA object which replaces the MiscRegFile.
This object encapsulates (or will eventually) the identity and characteristics
of the ISA in the CPU.
2009-07-08 23:02:20 -07:00
Gabe Black
b6bfe8af26 X86: Split out the internal memory space from the regular translate() and precompute mode. 2009-04-26 16:48:44 -07:00
Gabe Black
ee7055c289 X86: Put the StoreCheck flag with the others, and don't collide with other flags. 2009-04-23 01:43:00 -07:00
Gabe Black
6910baa015 X86: Fix how the TLB handles the storecheck flag. 2009-04-19 04:57:51 -07:00
Gabe Black
3b1b21cb15 X86: Some segment selectors can be used when "NULL". 2009-04-19 03:41:10 -07:00
Nathan Binkert
e0de2c3443 tlb: More fixing of unified TLB 2009-04-08 22:21:27 -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
Nathan Binkert
4523741c1c quell gcc 4.3 warning 2009-02-27 17:29:58 -08:00
Gabe Black
9dfa3f7f73 X86: Fix segment limit checks. 2009-02-27 09:23:50 -08:00
Gabe Black
c849ef58c0 X86: Actually check page protections. 2009-02-25 10:18:58 -08:00
Gabe Black
dc53ca89f6 X86: Add a flag to force memory accesses to happen at CPL 0. 2009-02-25 10:18:22 -08:00
Gabe Black
40fdba2454 X86: Make the X86 TLB take advantage of delayed translations, and get rid of the fake TLB miss faults. 2009-02-25 10:16:21 -08:00
Gabe Black
6ed47e9464 CPU: Implement translateTiming which defers to translateAtomic, and convert the timing simple CPU to use it. 2009-02-25 10:16:15 -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
e8c1c3e72e X86: Pass whether an access was a read/write/fetch so faults can behave accordingly. 2009-02-23 00:20:34 -08:00
Gabe Black
06cdbe5ea7 X86: Compute PCI config addresses correctly. 2009-02-01 00:11:49 -08:00
Nathan Binkert
9c49bc7b00 mem: update stuff for changes to Packet and Request 2008-11-10 11:51:17 -08:00
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
Gabe Black
42ebebf99a X86: Make the local APIC accessible through the memory system directly, and make the timer work. 2008-10-12 11:08:00 -07:00
Gabe Black
d9f9c967fb Turn Interrupts objects into SimObjects. Also, move local APIC state into x86's Interrupts object. 2008-10-12 09:09:56 -07:00
Gabe Black
6b8d0363ee X86: Rename the divide count register to divide configuration. 2008-06-12 00:54:12 -04:00
Gabe Black
66f54a6037 X86: Change how segment loading is performed. 2008-06-12 00:52:12 -04:00
Gabe Black
b05299253f X86: In non 64bit mode, throw a fault when a NULL segment is accessed. 2008-06-12 00:51:50 -04:00
Gabe Black
8688ef3fe5 X86: Have all 8 machine check registers since the kernel assumes they're there. 2008-06-12 00:48:02 -04:00
Gabe Black
a8e3001df8 X86: Bypass unaligned access support for register addressed MSRs. 2008-06-12 00:47:25 -04:00
Gabe Black
b3e55339f9 X86: Remove enforcement of APIC register access alignment. Panic if more than one register is accessed at a time. 2008-06-12 00:46:22 -04:00
Gabe Black
66aaabf4ae X86: Don't map the local APIC into the physical address space in SE mode.
--HG--
extra : convert_revision : b7103974b12130bbf43583c4cb5294b808add208
2008-03-01 00:05:12 -05:00
Gabe Black
43ecce5fda X86: Put in initial implementation of the local APIC.
--HG--
extra : convert_revision : 1708a93d96b819e64ed456c75dbb5325ac8114a8
2008-02-26 23:39:53 -05:00