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arch-riscv: Fixed CPU switching and PLIC issue with MinorCPU

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Added takeover methods for PMA Checker and RiscvTLB to ensure
that checkpoint restoration works. Also added logic in PLIC
to prevent posting interrupts to a CPU that has yet to complete
the current interrupt. PLIC's behaviour when a CPU claims another
interrupt before completion is also changed. Now PLIC will return
the uncompleted interrupt ID instead of return 0. This behaviour
is not documented in the specs but is designed this way to avoid
issues from CPU side (especially MinorCPU).

Change-Id: I68eaaf56d2c4d76cc1e0a1e2160f5abe184c2cd5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/41933
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ayaz Akram <yazakram@ucdavis.edu>
This commit is contained in:
Peter Yuen
2021-02-26 15:43:50 +07:00
committed by Andrea Mondelli
parent 7bb690c1ee
commit 975fcf1355
9 changed files with 67 additions and 13 deletions
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29
src/dev/riscv/plic.cc
View File

@@ -354,17 +354,18 @@ Plic::readClaim(Register32& reg, const int context_id)
context_id, max_int_id);
clear(max_int_id);
reg.update(max_int_id);
return reg.get();
} else {
DPRINTF(Plic,
"Claim already cleared - context: %d, interrupt ID: %d\n",
context_id, max_int_id);
reg.update(0);
return 0;
}
} else {
warn("PLIC claim failed (not completed) - context: %d", context_id);
reg.update(0);
warn("PLIC claim repeated (not completed) - context: %d, last: %d",
context_id, lastID[context_id]);
return lastID[context_id];
}
return reg.get();
}
void
@@ -381,6 +382,7 @@ Plic::writeClaim(Register32& reg, const uint32_t& data, const int context_id)
DPRINTF(Plic,
"Complete - context: %d, interrupt ID: %d\n",
context_id, reg.get());
updateInt();
}
void
@@ -445,11 +447,11 @@ Plic::updateInt()
uint32_t max_id = output.maxID[i];
uint32_t priority = output.maxPriority[i];
uint32_t threshold = registers.threshold[i].get();
if (priority > threshold && max_id > 0) {
if (priority > threshold && max_id > 0 && lastID[i] == 0) {
DPRINTF(Plic,
"Int posted - thread: %d, int id: %d, ",
thread_id, int_id);
DPRINTF(Plic,
DPRINTFR(Plic,
"pri: %d, thres: %d\n", priority, threshold);
intrctrl->post(thread_id, int_id, 0);
} else {
@@ -457,7 +459,7 @@ Plic::updateInt()
DPRINTF(Plic,
"Int filtered - thread: %d, int id: %d, ",
thread_id, int_id);
DPRINTF(Plic,
DPRINTFR(Plic,
"pri: %d, thres: %d\n", priority, threshold);
}
intrctrl->clear(thread_id, int_id, 0);
@@ -499,6 +501,12 @@ Plic::serialize(CheckpointOut &cp) const
SERIALIZE_SCALAR(n_outputs);
SERIALIZE_CONTAINER(output.maxID);
SERIALIZE_CONTAINER(output.maxPriority);
SERIALIZE_CONTAINER(pendingPriority);
for (int i=0; i < effPriority.size(); i++) {
arrayParamOut(cp, std::string("effPriority") +
std::to_string(i), effPriority[i]);
}
SERIALIZE_CONTAINER(lastID);
}
void
@@ -541,4 +549,11 @@ Plic::unserialize(CheckpointIn &cp)
}
UNSERIALIZE_CONTAINER(output.maxID);
UNSERIALIZE_CONTAINER(output.maxPriority);
UNSERIALIZE_CONTAINER(pendingPriority);
for (int i=0; i < effPriority.size(); i++) {
arrayParamIn(cp, std::string("effPriority") +
std::to_string(i), effPriority[i]);
}
UNSERIALIZE_CONTAINER(lastID);
updateInt();
}