Roger Chang has submitted this change. (
https://gem5-review.googlesource.com/c/public/gem5/+/69497?usp=email )
Change subject: arch-riscv: Refactor the shouldCheckPMP function
......................................................................
arch-riscv: Refactor the shouldCheckPMP function
The shouldCheckPMP can be simply with pmode != PRV_M since the
privilege mode of memory is modified by TLB and Walker. The
numRules check can done in shouldPMPCheck
Change-Id: I842687674fed7bc4d88a9ba6b4c4d52c3459068f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/69497
Maintainer: Bobby Bruce <bbr...@ucdavis.edu>
Tested-by: kokoro <noreply+kok...@google.com>
Reviewed-by: Yu-hsin Wang <yuhsi...@google.com>
---
M src/arch/riscv/pmp.cc
M src/arch/riscv/pmp.hh
2 files changed, 11 insertions(+), 28 deletions(-)
Approvals:
kokoro: Regressions pass
Bobby Bruce: Looks good to me, approved
Yu-hsin Wang: Looks good to me, approved
diff --git a/src/arch/riscv/pmp.cc b/src/arch/riscv/pmp.cc
index 6275104..8fa1ca3 100644
--- a/src/arch/riscv/pmp.cc
+++ b/src/arch/riscv/pmp.cc
@@ -59,7 +59,7 @@
Addr vaddr)
{
// First determine if pmp table should be consulted
- if (!shouldCheckPMP(pmode, mode, tc))
+ if (!shouldCheckPMP(pmode, tc))
return NoFault;
if (req->hasVaddr()) {
@@ -71,9 +71,6 @@
req->getPaddr());
}
- if (numRules == 0)
- return NoFault;
-
// match_index will be used to identify the pmp entry
// which matched for the given address
int match_index = -1;
@@ -273,26 +270,14 @@
}
bool
-PMP::shouldCheckPMP(RiscvISA::PrivilegeMode pmode,
- BaseMMU::Mode mode, ThreadContext *tc)
+PMP::shouldCheckPMP(RiscvISA::PrivilegeMode pmode, ThreadContext *tc)
{
- // instruction fetch in S and U mode
- bool cond1 = (mode == BaseMMU::Execute &&
- (pmode != RiscvISA::PrivilegeMode::PRV_M));
-
- // data access in S and U mode when MPRV in mstatus is clear
- RiscvISA::STATUS status =
- tc->readMiscRegNoEffect(RiscvISA::MISCREG_STATUS);
- bool cond2 = (mode != BaseMMU::Execute &&
- (pmode != RiscvISA::PrivilegeMode::PRV_M)
- && (!status.mprv));
-
- // data access in any mode when MPRV bit in mstatus is set
- // and the MPP field in mstatus is S or U
- bool cond3 = (mode != BaseMMU::Execute && (status.mprv)
- && (status.mpp != RiscvISA::PrivilegeMode::PRV_M));
-
- return (cond1 || cond2 || cond3 || hasLockEntry);
+ // The privilege mode of memory read and write
+ // is modified by TLB. It can just simply check if
+ // the numRule is not zero, then return true if
+ // privilege mode is not M or has any lock entry
+ return numRules != 0 && (
+ pmode != RiscvISA::PrivilegeMode::PRV_M || hasLockEntry);
}
AddrRange
diff --git a/src/arch/riscv/pmp.hh b/src/arch/riscv/pmp.hh
index 24cb4ad..ff8c4fc 100644
--- a/src/arch/riscv/pmp.hh
+++ b/src/arch/riscv/pmp.hh
@@ -118,7 +118,7 @@
* is allowed based on the pmp rules.
* @param req memory request.
* @param mode mode of request (read, write, execute).
- * @param pmode current privilege mode of execution (U, S, M).
+ * @param pmode current privilege mode of memory (U, S, M).
* @param tc thread context.
* @param vaddr optional parameter to pass vaddr of original
* request for which a page table walk is consulted by pmp unit
@@ -159,13 +159,11 @@
* This function is called during a memory
* access to determine if the pmp table
* should be consulted for this access.
- * @param pmode current privilege mode of execution (U, S, M).
- * @param mode mode of request (read, write, execute).
+ * @param pmode current privilege mode of memory (U, S, M).
* @param tc thread context.
* @return true or false.
*/
- bool shouldCheckPMP(RiscvISA::PrivilegeMode pmode,
- BaseMMU::Mode mode, ThreadContext *tc);
+ bool shouldCheckPMP(RiscvISA::PrivilegeMode pmode, ThreadContext *tc);
/**
* createAddrfault creates an address fault
--
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Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: I842687674fed7bc4d88a9ba6b4c4d52c3459068f
Gerrit-Change-Number: 69497
Gerrit-PatchSet: 5
Gerrit-Owner: Roger Chang <rogerycch...@google.com>
Gerrit-Reviewer: Ayaz Akram <yazak...@ucdavis.edu>
Gerrit-Reviewer: Bobby Bruce <bbr...@ucdavis.edu>
Gerrit-Reviewer: Hoa Nguyen <hoangu...@ucdavis.edu>
Gerrit-Reviewer: Jui-min Lee <f...@google.com>
Gerrit-Reviewer: Roger Chang <rogerycch...@google.com>
Gerrit-Reviewer: Yu-hsin Wang <yuhsi...@google.com>
Gerrit-Reviewer: kokoro <noreply+kok...@google.com>
Gerrit-MessageType: merged
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