In flat instructions, wrLmReqsInPipe/rdLmReqsInPipe are decremented
in the calcAddr() function. However, the calcAddr() function is only
called when execMask != 0.
This patch adds in statements to decrement wrLmReqsInPipe and
rdLmReqsInPipe in all implemented atomic flats when execMask is 0.
This fixes a scenario where vector local memory and flat instructions
are unable to execute due to LocalMemPipeline::isLMReqFIFOWrRdy
always returning false in ScheduleStage::dispatchReady after too many
atomic flats execute with execMask = 0
Change-Id: I081cfd3faf74bbfcf0728445e7160fa2a76a6a7e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32614
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Alexandru Duțu <alexandru.dutu@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
In most cases, the microcode ROM doesn't actually do anything. The
structural existence of a microcode ROM doesn't make sense in the
general case, and in architectures that know they have one and need to
interact with it, they can cast their decoder into an arch specific type
and access the ROM that way.
Change-Id: I25b67bfe65df1fdb84eb5bc894cfcb83da1ce64b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32898
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Some variables were being compared against some constants with "is not",
which is not correct since it will compare for identity rather than
equivalence. There was a long standing build warning from this, but it
wasn't clear where the error was coming from since it was in python
interpreted from a string in the ISA description.
This change replaces "is not" in those two places with "!=".
Change-Id: I0c4d038af6e047ffd79f8171713e8e998e840e3b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33283
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Original Creator: Adria Armejach.
Branch instructions needed to be annotated in x86 as direct/indirect and conditional/unconditional. These annotations where not present causing the branch predictor to misbehave, not using the BTB. In addition, logic to determine the real branch target at decode needed to be added as it was also missing.
Change-Id: I91e707452c1825b9bb4ae75c3f599da489ae5b9a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/29154
Reviewed-by: Alexandru Duțu <alexandru.dutu@amd.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This code was at least a little Alpha specific, and now that Alpha is
gone it can no longer be compiled. We could either fix it up to work
with other/all ISAs or delete it, and the consensus was to delete it. It
could potentially be revived in the future by retrieving it from version
control.
Change-Id: Ied073f2b9b166951ecba3442cd762eb19bc690b3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32954
Reviewed-by: Steve Reinhardt <stever@gmail.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Also remove it's Alpha centric implementation. All existing ISAs will
panic since they all define the guarding constant as false. Even if they
defined it as true, this function assumes that there is necessarily a misc
reg which can be read to find the current thread_info struct, and how
the contents of that register should be manipulated.
This code is already fairly fragile since it depends on things in the
Linux kernel having certain names and relationships with each other, but
that's a larger problem I don't want to fix right now.
Change-Id: Ic107793ebcd25ee25c4d3713c84c1d2b5209f1a3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32921
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The getDoubleBits function was used exactly once to find the bit
representation of a double floating point value, which is the same thing
the common floatToBits64 function does. Eliminate x86's one off version,
and use the common one instead.
Change-Id: Icb0cec5a55d81a6eacf1bb5a3c2b8f16c414d0d9
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32927
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The patch is aiming at speeding up gem5 execution. The TLB::translateFs
is in the critical path of the simulator: every fetch + ld/st will make
use of it.
Checking all the time for a breakpoint during fetch is rather expensive;
it is better to make use of the cached booleans in SelfDebug to do an
early check to see if any of
Watchpoint/Breakpopint/VectorCatch/SoftwareStep is enabled.
Most workloads won't use them so there's no point on calling the
testDebug method
Change-Id: I0189b84e0dc2e081acce04ff44787b9f1014477c
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32776
Tested-by: kokoro <noreply+kokoro@google.com>
* enableFlag -> mde
The "enableFlag" variable, enabling the Breakpoint, Watchpoint, Vector
Catch exceptions is actually the cached version of MDSCR_EL1.MDE. The
"enableFlag" name looks too general as it's not covering the Software
Step exception case.
* bKDE -> kde
* bSDD -> sdd
The b prefix was likely referring to "breakpoint". However these bitfields
are actually used by watchpoints as well.
Change-Id: I48b762b32b2d763f4c4ceb7dcc28968cfb470fc1
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32775
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
The NS field in PTEs descriptors is tagging Secure/Non-secure physical
memory (pages). This field is relevant in Secure state only:
While in Secure state, software can access both the Secure and
Non-secure physical address spaces, software in Non-secure state can
only access Non-secure memory; the NS bit is hence discarded/treated as
1.
This patch is aligning VMSAv8-32 with VMSAv8-64, which is tagging the
pointed memory as Non-secure in case of a Non-secure lookup.
The old behaviour was probably not leading to incorrect execution:
once a translation completes, the security flag in the memory request
is chcked against the security state of the cpu (and not only relying
on the NS bit in the TLB entry)
if (isSecure && !te->ns) {
req->setFlags(Request::SECURE);
}
so we were already forbidding secure accesses from non secure world
if NS = 0.
It is however misleading in the debug logs to see tlb entries with
NSTID = 1 and NS = 0.
Change-Id: I1f964069f88c33fb14362dd4101cb22538907226
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32638
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
debugExceptionReturnSS is called on an ERET instruction to
check for software step. The method was not using the
SPSR.width and it was relying on the more generic ELIs32 to
check the execution mode of the destination EL.
This is not only an efficiency problem: the helper might not work
when returning to EL0. In general it is not possible to
understand if EL0 is using AArch32 or AArch64 if the current
EL is not EL0 and EL1 is using AArch64.
This is instead visible by inspecting the spsr.width during the
execution of an ERET instruction
Change-Id: Ibc5a43633d0020139f2c0e372959a3ab4880da6e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32634
Tested-by: kokoro <noreply+kokoro@google.com>
Flat instructions free some of their registers through their memory
requests, in particuar a call to scheduleWriteOperandsFromLoad(),
which gets called from GlobalMemPipeline::exec.
When execMask is 0, the instruction doesn't issue a memory request.
This patch adds in a call to scheduleWriteOperandsFromLoad() when
execMask is 0 for Flat Load and AtomicReturn instructions, as those
are the instructions that call scheduleWriteOperandsFromLoad()
in the memory pipeline.
This patch also adds in a missing return statement when execMask is 0
in one of the Flat instructions.
Change-Id: I09296adb7401e7515d3cedceb780a5df4598b109
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32234
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Before this commit:
* SEV events were not waking neither WFE (wrong) nor futex WAIT (correct)
* locked memory events (LLSC) due to LDXR and STXR were waking up both
WFE (correct) and futex WAIT (wrong)
This commit fixes all wrong behaviours mentioned above.
The fact that LLSC events were waking up futexes leads to deadlocks,
as shown in the test case described at:
https://gem5.atlassian.net/browse/GEM5-537
because threads woken up by SVE are not removed from the waiter list
for the futex address they are sleeping on.
A previous fix atttempt was done at:
1531b56d605d47252dc0620bb3e755b7cf84df97
in which only sleeping threads are woken up. But that is not sufficient,
because the futex sleeping thread that was being wrongly woken up on SEV
can start to sleep on a second futex.
As an example, consider the case where 4 threads are fighting over two
critical sections protected by futex1 and futex2 addresses. In this case,
one thread wakes up the other thread after it is done with the section.
Suppose the following sequence of events:
* thread1 is awake and all others are suspended on futex1
* thread1 SEV wakes thread2 from the futex1 while in the critical region 1.
This is the wrong behaviour that this patch prevents, because
now thread2 is still in the sleeper list for futex1
* thread1 then futex wakes tread3, then proceeds to critical region 2.
* thread3 wakes up, but because thread2 has critical region, it sleeps
again.
* thread2 finishes its work, futex wakes thread3, and then proceeds to
futex2
When it reaches futex2, thread1 is still working there, so it sleeps on
futex2.
* thread3 futex wakes thread2, because it is still wrongly on the sleeper
list of futex1. But thread2 is in futex2 now.
If it weren't for this mistake, it should have awaken the final thread4
instead.
Outcome: thread4 sleeps forever, no other thread ever wakes it, because all
other threads have woken from futex1 and awoken another thread.
The problem is fixed by adding the waitingTcs unordered_set FutexMap,
which is basically an inverse map to FutexMap, which tracks (addr,
tgid) -> ThreadContext. This allows us allow to quickly check
if a given ThreadContext is waiting on a futex in any address.
Then the SEV wakeup code path
now checks if the thread is k
Change-Id: Icec5e30b041f53e5aa3b6e0d291e77bc0e865984
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/29777
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
