dev-arm: Read correct version of ICC_BPR register

Some methods like groupPriorityMask check for the value of binary point
registers. Those registers have a minimum value.  Writing to those
register is taking this into account, but the problem with the minimum
value arises when the value is checked before sw is writing to them.
In this case the minimum value won't be considered if the read is
directly forwarded to the ISA class.

Change-Id: Id432a37f1634b02bc478d65c52ffb88323d4bb77
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18598
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/src/dev/arm/gic_v3_cpu_interface.cc b/src/dev/arm/gic_v3_cpu_interface.cc
index 3598f34d0144bd690f449a6fef228eaccf7bda9b..4a0a8e3403b78359998833ecbd9daf706227e0f4 100644 (file)
--- a/src/dev/arm/gic_v3_cpu_interface.cc
+++ b/src/dev/arm/gic_v3_cpu_interface.cc
@@ -36,6 +36,9 @@
 #include "dev/arm/gic_v3_distributor.hh"
 #include "dev/arm/gic_v3_redistributor.hh"
 
+const uint8_t Gicv3CPUInterface::GIC_MIN_BPR;
+const uint8_t Gicv3CPUInterface::GIC_MIN_BPR_NS;
+
 Gicv3CPUInterface::Gicv3CPUInterface(Gicv3 * gic, uint32_t cpu_id)
     : BaseISADevice(),
       gic(gic),
@@ -322,6 +325,8 @@ Gicv3CPUInterface::readMiscReg(int misc_reg)
                 bpr = isa->readMiscRegNoEffect(MISCREG_ICC_BPR0_EL1);
             } else {
                 bpr = isa->readMiscRegNoEffect(MISCREG_ICC_BPR1_EL1);
+                bpr = std::max(bpr, group == Gicv3::G1S ?
+                    GIC_MIN_BPR : GIC_MIN_BPR_NS);
             }
 
             if (sat_inc) {
@@ -1844,7 +1849,7 @@ Gicv3CPUInterface::virtualDeactivateIRQ(int lr_idx)
  * GroupBits() Pseudocode from spec.
  */
 uint32_t
-Gicv3CPUInterface::groupPriorityMask(Gicv3::GroupId group) const
+Gicv3CPUInterface::groupPriorityMask(Gicv3::GroupId group)
 {
     ICC_CTLR_EL1 icc_ctlr_el1_s =
         isa->readMiscRegNoEffect(MISCREG_ICC_CTLR_EL1_S);
@@ -1859,9 +1864,9 @@ Gicv3CPUInterface::groupPriorityMask(Gicv3::GroupId group) const
     int bpr;
 
     if (group == Gicv3::G0S) {
-        bpr = isa->readMiscRegNoEffect(MISCREG_ICC_BPR0_EL1) & 0x7;
+        bpr = readMiscReg(MISCREG_ICC_BPR0_EL1) & 0x7;
     } else {
-        bpr = isa->readMiscRegNoEffect(MISCREG_ICC_BPR1_EL1) & 0x7;
+        bpr = readMiscReg(MISCREG_ICC_BPR1_EL1) & 0x7;
     }
 
     if (group == Gicv3::G1NS) {
@@ -2165,7 +2170,7 @@ Gicv3CPUInterface::intSignalType(Gicv3::GroupId group) const
 }
 
 bool
-Gicv3CPUInterface::hppiCanPreempt() const
+Gicv3CPUInterface::hppiCanPreempt()
 {
     if (hppi.prio == 0xff) {
         // there is no pending interrupt

diff --git a/src/dev/arm/gic_v3_cpu_interface.hh b/src/dev/arm/gic_v3_cpu_interface.hh
index 931eb1df886d0f485f65f5059927cf361fbdde5c..e6dcb51ff31819abffe121d7712faa7da7ea89fe 100644 (file)
--- a/src/dev/arm/gic_v3_cpu_interface.hh
+++ b/src/dev/arm/gic_v3_cpu_interface.hh
@@ -296,11 +296,11 @@ class Gicv3CPUInterface : public ArmISA::BaseISADevice, public Serializable
     uint32_t getHPPIR1() const;
     int getHPPVILR() const;
     bool groupEnabled(Gicv3::GroupId group) const;
-    uint32_t groupPriorityMask(Gicv3::GroupId group) const;
+    uint32_t groupPriorityMask(Gicv3::GroupId group);
     bool haveEL(ArmISA::ExceptionLevel el) const;
     int highestActiveGroup() const;
     uint8_t highestActivePriority() const;
-    bool hppiCanPreempt() const;
+    bool hppiCanPreempt();
     bool hppviCanPreempt(int lrIdx) const;
     bool inSecureState() const;
     ArmISA::InterruptTypes intSignalType(Gicv3::GroupId group) const;