The IsInvalid flag indicates that the static instruction is not part of
the executing ISA and not part of m5's pseudo-instructions. This flag
provides a way to recognize an illegal instruction at the decode stage.
When a compute unit issues several requests to the same line,
the requests wait in the L2 if it is a writeback cache. If the line is
invalid initially and the first request is atomic in nature, the L2
cache issues a request to main memory. On data return, the cache line
transitions to M but doesn't wake up the other requests, resulting in
a deadlock. This commit adds a wakeup call on data return for atomics
and fixes potential deadlocks.
This PR incorporates numerous improvements and fixes to the gem5
PyStats. This includes:
* PyStats now support SimObject Vectors. The PyStats representing them
are subscribable and therefore acceptable by accessing an index: e.g.,:
`simobjectvec[0]`. (This replaces the `Vector` group PyStat)
* Adds the `SparseHist` PyStats.
* Adds the `Vector2d` to PyStats.
* The `Distribution` PyStats is fixed to be a vector of Scalars.
* Tests added for the PyStat's Vector and bugs fixed.
This commit adds instSeqNum to the atomic responses in
GPU_VIPER-TCC.sm. This will be useful when debugging issues related to
GPU atomic transactions
Change-Id: Ic05c8e1a1cb230abfca2759b51e5603304aadaa3
When a compute unit issues several requests to the same line,
the requests wait in the L2 if it is a writeback cache. If the line is
invalid initially and the first request is atomic in nature, the L2
cache issues a request to main memory. On data return, the cache line
transitions to M but doesn't wake up the other requests, resulting in
a deadlock. This commit adds a wakeup call on data return for atomics
and fixes potential deadlocks.
Change-Id: I8200ce6e77da7c8b4db285c0cc8b8ca0dfa7d720
The IsInvalid flag indicates that the static instruction is not part
of the executing ISA and not part of m5's pseudo-instructions. This
flag provides a way to recognize an illegal instruction at the decode
stage.
Change-Id: I2779c6edcd8c5e6a77ea11cad3ff73bacb79d800
Signed-off-by: Hoa Nguyen <hn@hnpl.org>
When accessing memory using functionalAccess(), the MMU could tell us to
use a nonsecure access even though the CPU is operating in secure mode.
I noticed this while trying to run a simple semihosting hello world with
the MMU+caches enabled and the semihosting calls ended up reading from
memory instead of the caches due to an S/NS mismatch.
See also https://github.com/gem5/gem5/pull/1198 which happens to also
mask the issue I saw, but I believe both changes are needed.
Change-Id: I9e6b9839b194fbd41938e2225449c74701ea7fee
Some arithmetic instructions of the riscv vector extension where still
using the default VLEN=256 instead of the dynamic one through the
inherited `vlen` attribute. Most of them only use this to calculate the
effective index for the mask element like so:
```
uint32_t ei = i + vtype_VLMAX(vtype, vlen, true) * this->microIdx;
if (this->vm || elem_mask(v0, ei)) {
...
```
This means that instructions will wrongly compute the mask index in the
second and subsequent micro instructions (`microIdx` > 0). This commit
fixes this by adding the corresponding `set_vlen` snippet to the
affected instruction formats.
Change-Id: Ib041de972d6938490741a9fb4c214a6a5172c34e
While running a simple Arm32 binary, I noticed that all memory
transactions were being marked as NS instead of S once I turn on the MMU
(even though the page tables have the NS bit set to zero). The result of
this was that semihosting calls were failing since they were using
functional accesses with the SECURE flag set, but the caches only
contained NS tagged entries so these accesses always read stale values
from DRAM.
Digging through the Arm MMU code it appears that the NS bit lookup was
being keyed of the `secureLookup` flag which is only used for long
descriptors. I believe 0c28712f51 should
have used isSecure instead of secureLookup. To avoid using these
uninitialized values in the future I wrapped the LPAE state in a
std::optional to ensure that it is only accessed once initialized.
Change-Id: Ibc406ed3f4cfa768f470e34a5eca3c1a2bf45cd8
The SYS_WRITEC and SYS_WRITE0 calls are specified as writing to the
debug channel, so it is a reasonable expectation for these messages to
be visibile immediately after the semihosting call.
Change-Id: I8e6e9a7aab593a59e82ecb9cf4603c18c7a8acbe
Clang warns as follows: `warning: definition of implicit copy
constructor for 'TranslResult' is deprecated because it has a
user-declared copy assignment operator`
Change-Id: Ic701d8522aac75d569f4f513f54de91f76a17e48
`src/dev/virtio/VirtIORng 2.py` is identical to
`src/dev/virtio/VirtIORng.py`, and the former does not appear in any
build script.
Change-Id: I9c5f1b1a3809d1c7028b630c32310e540613e232
Signed-off-by: Hoa Nguyen <hn@hnpl.org>
Fixed the assertion statement in the cpu's translation.hh file so that
it doesn't fail the assertion if the cache is clean.
I compile this c code to `test`
```c
#include <stdio.h>
static inline void clflush(volatile void *p) {
__asm__ volatile ("clflush (%0)" : : "r"(p) : "memory");
}
int main() {
int data = 42; // Example variable
printf("Value before clflush: %d\n", data);
clflush(&data);
printf("Value after clflush: %d\n", data);
return 0;
}
```
And run it with this script
`./build/X86/gem5.opt configs/learning_gem5/part1/two_level.py ./test`
In order to verify that it no longer fails the assertion check.
GitHub Issue: #862
Change-Id: I6004662e7c99f637ba0ddb07d205d1657708e99f
This feature has been available since Vega10 but was never implemented.
MI300 adds a few new instructions that make use of this more often
(e.g., v_mov_b64).
Change-Id: Ieeb7834462b76d77c0030f49622d0de09f90c9e4
This instruction is a simple move from accumulation register to
accumulation register. It is essentially a move with the accumulation
offset added to the register index.
Change-Id: Ic93ae72599b75c91213f56ebafe5bbd7b2867089
Flat, scratch, and global share the same instruction implementation with
different address calculations essentially. These instructions were
already implemented but not added to the decoder. This commit adds the
remaining scratch instructions which have a shared instruction
implementation.
Change-Id: I8f2e9ceb221294dce1b81c45745b642f0592d985
The lines `constexpr int B_I = std::ceil(64.0f / (N * M / H));` caused
the following compilation error in clang Version 16:
```
error: constexpr variable 'B_I' must be initialized by a constant
expression
```
`std::ceil` is not a const expression. Therefore instances of this
expression in instructions.hh have been replaced with a constant
expression friendly alternative.
This is calling our compiler tests to fail:
https://github.com/gem5/gem5/actions/runs/9288296434/job/25559409142
Change-Id: I74da1dab08b335c59bdddef6581746a94107f370
Currently when data is downgraded by MOESI_AMD_Base-CorePair (e.g. due
to a replacement) this requires a 4-way handshake between the CorePair
and the dir. Specifically, the CorePair send a message telling the dir
it'd like to downgrade then, the dir sends an ACK back and then, the
CorePair writes the data back, and finally, the dir ACKs the writeback.
This is very inefficient and not representative of how modern protocols
downgrade a request. Accordingly, this commits updates the downgrade
support such that the CorePair writes back the data immediately and then
the dir ACKs it.
Thus, this approach requires only a 2-way handshake.
Change-Id: I7ebc85bb03e8ce46a8847e3240fc170120e9fcd6
Co-authored-by: Neeraj Surawar <neerajs@hyrule.cs.wisc.edu>
Bigs fixed of note:
1. The 'find' method has been fixed to work. This involved making
'children' a class implemented per-subclass as required.
2. The 'get_all_stats_of_name' method has been removed. This was not
working at all correctly and is largely doing what 'find' does.
2. The functionality to get an element in a vector via an attribute call
(i.e., self.vector1 == self.vector[1]) has been implemented this
maintaining backwards compatibility with the regular Python stats.
Change-Id: I31a4ccc723937018a3038dcdf491c82629ddbbb2
The SimStat Object is nothing more than a group of other SimStats and is
therefore logically a group. With this, functionality can be shared more
easily.
Change-Id: I5dce23a02d5871e640b422654ca063e590b1429a
When compiler tries to inline a vector construction with a default value
as default constructed ReplaceableEntry. It can complain about the
uninitialized member.
Let's provide basic initialization to the members.
Example codepath:
SignaturePathV2 constructor
-> GlobalHistoryEntry() as init_value to AssociativeSet
-> AssociativeSet initialize vector<Entry> with init_value
1. Adds newly added PyStat classes to "__init__.py", ensuring they can
all be accessed via a `m5.ext.pystats` import.
2. Simplifies the layout out "__init__.py" to just import all classes
from all files.
Change-Id: I43bfc5e7ff1aec837e661905304c6fb10b00c90e
This PR is doing the following:
1) Fixing memory attributes of partial translation entries (table walks)
2) Properly setting the cacheability of table walks
Fix#1168. Prevent logical instructions like AND, OR, and TEST from
having input dependencies on the previous value of the Zaps register
(ZF+AF+PF+SF) by having them set AF=0, rather than not modifying AF.
Fix#1169. Break the input dependency of 32-bit and 64-bit 'mov'
micro-ops on the prior value in the destination register. Such a
dependency is required for 8-bit and 16-bit moves, as they do not
completely overwrite the value in the destination register. However, it
is unnecessary for 32-bit moves (which implicitly zero the upper 32
bits) and 64-bit moves.
This patch implements the fix by adding a new code template field inside
the generated constructors of X86StaticInst's, called `invalidate_srcs`,
which instruction implementations like `mov` can use to conditionally
invalidate particular source registers as needed. In `mov`'s case, this
is when the data size is 32 or 64 bits.
Change-Id: Ib2aef6be6da08752640ea3414b90efb7965be924
SDMA RLC queues do not currently remove their doorbell mapping. This can
cause issues re-registering the queue and prevents the pending doorbells
feature from working. In addition the data value of the doorbell (the
ring buffer rptr) is not saved, leading to UB when this workaround is
used.
This commit removes the doorbell mapping from the gpu device when the
SDMA engine unmaps an RLC queue and copies the next doorbell value to
the pending packet as was originally intended.
Change-Id: Ifd551450f439c065579afcf916f8ff192e7598ab
According to the Arm architecture reference manual, it is possible to
force the broadcast of the following TLBIs:
AArch64: TLBI VMALLE1, TLBI VAE1, TLBI ASIDE1, TLBI VAAE1, TLBI VALE1,
TLBI VAALE1, IC IALLU, TLBI RVAE1, TLBI RVAAE1, TLBI RVALE1, and TLBI
RVAALE1.
AArch32: BPIALL, TLBIALL, TLBIMVA, TLBIASID, DTLBIALL, DTLBIMVA,
DTLBIASID, ITLBIALL, ITLBIMVA, ITLBIASID, TLBIMVAA, ICIALLU, TLBIMVAL,
and TLBIMVAAL.
Via the HCR_EL2.FB bit
Change-Id: Ib11aa05cd202fadfbd9221db7a2043051196ecbd
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
When determining the cacheability of table walks,
SCTLR.C should only be used in stage1 EL1&0 translations.
Stage2 translations should rely on HCR_EL2.CD instead
Change-Id: I1b0830bc3fb5086f68d7a7a1560c7fed5d126d28
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Make table walks uncacheable if marked as uncacheable
in either inner or outer shareable domain
Change-Id: I5898a3b91b5b919e0beda6c6fe896394e3ab94df
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
StoreThrough in VIPER when the TCP is disabled, GLC bit is set, or SLC
bit is set will bypass the TCP, but will temporarily allocate a cache
entry seemingly to handle write coalescing with valid blocks. It does
not attempt to evict a block if the set is full and the address is
invalid. This causes a panic if the set is full as there is no spare
cache entry to use temporarily to use for DataBlk manipulation. However,
a cache block is not required for this.
This commit removes using a cache block for StoreThrough with invalid
blocks as there is no existing data to coalesce with. It creates no
allocate variants of the actions needed in StoreThrough and pulls the
DataBlk information from the in_msg instead. Non-invalid blocks do not
have this panic as they have a cache entry already.
Fixes issues with StoreThroughs on more aggressive architectures like
MI300.
Change-Id: Id8687eccb991e967bb5292068cbe7686e0930d7d
Those AArch64 instructions/registers were labelled as executable
from EL3 only if SCR_EL3.NS == 1. This is not valid anymore
after the introduction of FEAT_SEL2
The new static analysis in GCC 13 finds issues with operand.hh. This
commit fixes the error so that gem5 compiles when BUILD_GPU is true.
Change-Id: I6f4b0d350f0cabb6e356de20a46e1ca65fd0da55
Those AArch64 instructions/registers were labelled as executable
from EL3 only if SCR_EL3.NS == 1. This is not valid anymore
after the introduction of FEAT_SEL2
Change-Id: Ie7b56f3fe779c3a99d4f0ef937c7c8ec0530b00e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
This is making it easier for TLBI instructions to share code. Common
code (under the form of tlbi* functions) are closely matching the
instruction description in the Arm pseudocode
Change-Id: If10c22fb4a7df2bcd0335e9761286ad3c458722b
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
This commit addresses Jason's comment
(https://github.com/gem5/gem5/pull/996#discussion_r1613870880) which
highlighted putting the `_m5.stats.processDumpQueue` call in the
iteration through the `root` object in `get_simstat` caused this
function be potentially called many times when it only needs to be
called once. This chance moved this call to just before this iteration
and will tehrefore only be called once (if required) per `get_simstat`
execution.
Change-Id: I16908b6dee063a0df7877a19e215883963bfb081
The bit 0 of register should be 0 for jump address. Wrong handling the
jump address may cause infinite run or segment fault.
gem5 issue: https://github.com/gem5/gem5/issues/981
