Regularize control flow in dirty-bit test

diff --git a/isa/rv64si/dirty.S b/isa/rv64si/dirty.S
index 17aa57f7145c67563d891772132f763d8a2e2205..50bdcfb0d07d8646f9874840f73b3cab0fdbf4d3 100644 (file)
--- a/isa/rv64si/dirty.S
+++ b/isa/rv64si/dirty.S
@@ -28,7 +28,7 @@ RVTEST_CODE_BEGIN
   # Try a faulting store to make sure dirty bit is not set
   li TESTNUM, 2
   li t2, 1
-  sw t2, dummy - DRAM_BASE, t1
+  sw t2, dummy - DRAM_BASE, a0
 
   # Set SUM=1 so user memory access is permitted
   li TESTNUM, 3
@@ -40,7 +40,7 @@ RVTEST_CODE_BEGIN
   bnez t0, die
 
   # Try a non-faulting store to make sure dirty bit is set
-  sw t2, dummy - DRAM_BASE, t1
+  sw t2, dummy - DRAM_BASE, a0
 
   # Make sure it succeeded
   lw t0, dummy - DRAM_BASE
@@ -52,9 +52,9 @@ RVTEST_CODE_BEGIN
 
   # Make sure D bit is set
   lw t0, page_table_1
-  li t1, PTE_A | PTE_D
-  and t0, t0, t1
-  bne t0, t1, die
+  li a0, PTE_A | PTE_D
+  and t0, t0, a0
+  bne t0, a0, die
   
   RVTEST_PASS
 
@@ -81,12 +81,16 @@ skip:
 1:
   li t1, 3
   bne TESTNUM, t1, 1f
-  # The implementation doesn't appear to set D bits in HW.  Skip the test,
-  # after making sure the D bit is clear.
+  # The implementation doesn't appear to set D bits in HW.
+  # Make sure the D bit really is clear.
   lw t0, page_table_1
   and t1, t0, PTE_D
   bnez t1, die
-  j pass
+  # Set the D bit.
+  or t0, t0, PTE_D
+  sw t0, page_table_1, t1
+  sfence.vma
+  mret
 
 1:
 die: