arch-riscv: fix incorrect interrupt checking logic

Whether global interrupt enabling or not is not simply decided by
xIE bit in mstatus, it also depends on current privilige level.
All level lower/higher than current should be disabled/enabled
regardless of the xIE bit. xIE bit is only control the enabling
of interrupt in current privilige level.

The fix is verified in FS.

Jira Issue: https://gem5.atlassian.net/browse/GEM5-883

Change-Id: I37f83ab77af2efbf1da9b81845828d322e49bf5f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39035
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Ayaz Akram <yazakram@ucdavis.edu>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/src/arch/riscv/interrupts.hh b/src/arch/riscv/interrupts.hh
index fba925e205406a8c8ba9cce086ba51ad7e1b63d3..e1460ab7a14add9bd6162cdee8e0b18b08e07365 100644 (file)
--- a/src/arch/riscv/interrupts.hh
+++ b/src/arch/riscv/interrupts.hh
@@ -72,12 +72,31 @@ class Interrupts : public BaseInterrupts
     {
         INTERRUPT mask = 0;
         STATUS status = tc->readMiscReg(MISCREG_STATUS);
-        if (status.mie)
-            mask.mei = mask.mti = mask.msi = 1;
-        if (status.sie)
-            mask.sei = mask.sti = mask.ssi = 1;
-        if (status.uie)
-            mask.uei = mask.uti = mask.usi = 1;
+        PrivilegeMode prv = (PrivilegeMode)tc->readMiscReg(MISCREG_PRV);
+        switch (prv) {
+            case PRV_U:
+                mask.mei = mask.mti = mask.msi = 1;
+                mask.sei = mask.sti = mask.ssi = 1;
+                if (status.uie)
+                    mask.uei = mask.uti = mask.usi = 1;
+                break;
+            case PRV_S:
+                mask.mei = mask.mti = mask.msi = 1;
+                if (status.sie)
+                    mask.sei = mask.sti = mask.ssi = 1;
+                mask.uei = mask.uti = mask.usi = 0;
+                break;
+            case PRV_M:
+                if (status.mie)
+                     mask.mei = mask.mti = mask.msi = 1;
+                mask.sei = mask.sti = mask.ssi = 0;
+                mask.uei = mask.uti = mask.usi = 0;
+                break;
+            default:
+                panic("Unknown privilege mode %d.", prv);
+                break;
+        }
+
         return std::bitset<NumInterruptTypes>(mask);
     }