Apply the gem5 namespace to the codebase.
Some anonymous namespaces could theoretically be removed,
but since this change's main goal was to keep conflicts
at a minimum, it was decided not to modify much the
general shape of the files.
A few missing comments of the form "// namespace X" that
occurred before the newly added "} // namespace gem5"
have been added for consistency.
std out should not be included in the gem5 namespace, so
they weren't.
ProtoMessage has not been included in the gem5 namespace,
since I'm not familiar with how proto works.
Regarding the SystemC files, although they belong to gem5,
they actually perform integration between gem5 and SystemC;
therefore, it deserved its own separate namespace.
Files that are automatically generated have been included
in the gem5 namespace.
The .isa files currently are limited to a single namespace.
This limitation should be later removed to make it easier
to accomodate a better API.
Regarding the files in util, gem5:: was prepended where
suitable. Notice that this patch was tested as much as
possible given that most of these were already not
previously compiling.
Change-Id: Ia53d404ec79c46edaa98f654e23bc3b0e179fe2d
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/46323
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The systemc dir was not included in this fix.
First it was identified that there were only occurrences
at 0, 1, and 2 levels of indentation, using:
grep -nrE --exclude-dir=systemc \
"^ *class [A-Za-z].* {$" src/
Then the following commands were run to replace:
<indent level>class X ... {
by:
<indent level>class X ...
<indent level>{
Level 0:
grep -nrl --exclude-dir=systemc
"^class [A-Za-z].* {$" src/ | \
xargs sed -Ei \
's/^class ([A-Za-z].*) \{$/class \1\n\{/g'
Level 1:
grep -nrl --exclude-dir=systemc \
"^ class [A-Za-z].* {$" src/ | \
xargs sed -Ei \
's/^ class ([A-Za-z].*) \{$/ class \1\n \{/g'
and so on.
Change-Id: I17615ce16a333d69867b27c7bae0f4fdafd8b2eb
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39015
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.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>
Both methods do basically the same, especially since they don't handle the
timeout which is basically the only difference between both modes of the
syscall (one uses absolute and the other relative time).
Remove the WaiterState::WaiterState(ThreadContext* _tc) constructor,
since the only calls were from FutexMap::suspend which does not use them
anymore. Instead, set the magic 0xffffffff constant as a parameter to
suspend_bitset.
Change-Id: I69d86bad31d63604657a3c71cf07e5623f0ea639
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/29776
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
At Ia6b4d3e6148c64721d810b8f1fffaa208a394b06 the futex wake up started
skipping selecting threads that are already awake, which already prevented
some deadlocks.
However, threads that are Halting or Halted should not be woken up either,
as those represent cores in which processes have already exited.
Before this commit, this could lead an exited core to wake up, which would
then immediately re-execute the exit syscall, and possibly leave one
genuinely sleeping core locked and:
Exiting @ tick 18446744073709551615 because simulate() limit reached
Change-Id: I1531b56d605d47252dc0620bb3e755b7cf84df97
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22963
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
FutexMap::wakeup is called when the futex(TGT_FUTEX_WAKE syscall is done.
FutexMap maintains a list of sleeping threads for each futex address
added on FutexMap::suspend, and entries are removed from the list
at FutexMap::wakeup.
The problem is that this system was not taking into account that threads
can be woken up by memory accesses to locked addresses via the path:
SimpleThread::activate
BaseSimpleCPU::wakeup
AbstractMemory::checkLockedAddrList
AbstractMemory::access
DRAMCtrl::recvAtomic
CoherentXBar::recvAtomicBackdoor
SimpleExecContext::writeMem
which happens on trivial pthread examples on ARM at least. The instruction
that locked memory in those test cases was LDAXR.
This could lead futex(TGT_FUTEX_WAKE to awake a thread that is already
awake but is first on the sleeping thread list, instead of a sleeping one,
which can lead all threads to incorrectly sleep and in turn to
"simulate() limit reached".
To implement this, ThreadContext::activate return now returns a boolean
that indicates if the state changed. suspend and halt are also modified
to also return a boolean in the same case for symmetry, although this is
not strictly necessary for the current patch.
Change-Id: Ia6b4d3e6148c64721d810b8f1fffaa208a394b06
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21606
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This patch supports FUTEX_CMP_REQUEUE operation. Below is its
description from Linux man page:
futex syscall: int futex(int *uaddr, int futex_op, int val,
const struct timespec *timeout,
int *uaddr2, int val3);
This operation first checks whether the location uaddr still contains
the value val3. If not, the operation fails with the error EAGAIN.
Otherwise, the operation wakes up a maximum of val waiters that are
waiting on the futex at uaddr. If there are more than val waiters, then
the remaining waiters are removed from the wait queue of the source
futex at uaddr and added to the wait queue of the target futex at
uaddr2. The val2 argument specifies an upper limit on the number of
waiters that are requeued to the futex at uaddr2.
Reference: http://man7.org/linux/man-pages/man2/futex.2.html
Change-Id: I6d2ebd19a935b656d19d8342f7ab450c0d2031f4
Reviewed-on: https://gem5-review.googlesource.com/c/9629
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
This patch adds support for two operations in futex system call:
FUTEX_WAIT_BITSET and FUTEX_WAKE_BITSET. The two operations are used to
selectively wake up a certain thread waiting on a futex variable.
Basically each thread waiting on a futex variable is associated with a
bitset that is checked when another thread tries to wake up all threads
waiting on the futex variable.
Change-Id: I2300e53b144d8fae226423fa2efb0238c1d93ef9
Reviewed-on: https://gem5-review.googlesource.com/c/9621
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
The changeset does a major refactor on the exit, exit_group, and
futex system calls regarding exit functionality.
A FutexMap class and related structures are added into a new
file. This increases code clarity by encapsulating the futex
operations and the futex state into an object.
Several exit conditions were added to allow the simulator to end
processes under certain conditions. Also, the simulation only
exits now when all processes have finished executing.
Change-Id: I1ee244caa9b5586fe7375e5b9b50fd3959b9655e
Reviewed-on: https://gem5-review.googlesource.com/2269
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
