From c066a09ce18eb9252892d105386b40fa80242120 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <andrew@sifive.com>
Date: Thu, 30 Mar 2017 00:30:29 -0700
Subject: [PATCH 1/1] Expand dirty-bit test to test MPRV and SUM

---
 isa/rv64si/dirty.S | 57 ++++++++++++++++++++++++----------------------
 1 file changed, 30 insertions(+), 27 deletions(-)

diff --git a/isa/rv64si/dirty.S b/isa/rv64si/dirty.S
index 86e4656..17aa57f 100644
--- a/isa/rv64si/dirty.S
+++ b/isa/rv64si/dirty.S
@@ -13,40 +13,45 @@
 RVTEST_RV64M
 RVTEST_CODE_BEGIN
 
-  # Turn on VM with superpage identity mapping
+  # Turn on VM
   li a0, (SPTBR_MODE & ~(SPTBR_MODE<<1)) * SPTBR_MODE_SV39
   la a1, page_table_1
   srl a1, a1, RISCV_PGSHIFT
   or a1, a1, a0
-  la a2, page_table_2
-  srl a2, a2, RISCV_PGSHIFT
-  or a2, a2, a0
   csrw sptbr, a1
   sfence.vma
-  li a1, ((MSTATUS_MPP & ~(MSTATUS_MPP<<1)) * PRV_S) | MSTATUS_SUM
+
+  # Set up MPRV with MPP=S, so loads and stores use S-mode
+  li a1, ((MSTATUS_MPP & ~(MSTATUS_MPP<<1)) * PRV_S) | MSTATUS_MPRV
   csrs mstatus, a1
-  la a1, 1f - DRAM_BASE
-  csrw mepc, a1
-  la a1, stvec_handler - DRAM_BASE
-  csrw stvec, a1
-  mret
-1:
 
   # Try a faulting store to make sure dirty bit is not set
   li TESTNUM, 2
-  li t0, 1
-  sw t0, dummy, t1
+  li t2, 1
+  sw t2, dummy - DRAM_BASE, t1
 
-  # Load new page table
+  # Set SUM=1 so user memory access is permitted
   li TESTNUM, 3
-  csrw sptbr, a2
-  sfence.vma
+  li a1, ((MSTATUS_MPP & ~(MSTATUS_MPP<<1)) * PRV_S) | MSTATUS_SUM
+  csrs mstatus, a1
+
+  # Make sure SUM=1 works
+  lw t0, dummy - DRAM_BASE
+  bnez t0, die
 
   # Try a non-faulting store to make sure dirty bit is set
-  sw t0, dummy, t1
+  sw t2, dummy - DRAM_BASE, t1
+
+  # Make sure it succeeded
+  lw t0, dummy - DRAM_BASE
+  bne t0, t2, die
+
+  # Leave MPRV
+  li t0, MSTATUS_MPRV
+  csrc mstatus, t0
 
   # Make sure D bit is set
-  lw t0, page_table_2
+  lw t0, page_table_1
   li t1, PTE_A | PTE_D
   and t0, t0, t1
   bne t0, t1, die
@@ -56,8 +61,8 @@ RVTEST_CODE_BEGIN
   TEST_PASSFAIL
 
   .align 2
-stvec_handler:
-  csrr t0, scause
+mtvec_handler:
+  csrr t0, mcause
   add t0, t0, -CAUSE_STORE_PAGE_FAULT
   bnez t0, die
 
@@ -68,17 +73,17 @@ stvec_handler:
   and t1, t0, PTE_D
   bnez t1, die
 skip:
-  csrr t0, sepc
+  csrr t0, mepc
   add t0, t0, 4
-  csrw sepc, t0
-  sret
+  csrw mepc, t0
+  mret
 
 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.
-  lw t0, page_table_2
+  lw t0, page_table_1
   and t1, t0, PTE_D
   bnez t1, die
   j pass
@@ -95,9 +100,7 @@ RVTEST_DATA_BEGIN
   TEST_DATA
 
 .align 12
-page_table_1: .dword (DRAM_BASE/RISCV_PGSIZE << PTE_PPN_SHIFT) | PTE_V | PTE_U | PTE_R | PTE_X | PTE_A
+page_table_1: .dword (DRAM_BASE/RISCV_PGSIZE << PTE_PPN_SHIFT) | PTE_V | PTE_U | PTE_R | PTE_W | PTE_X | PTE_A
 dummy: .dword 0
-.align 12
-page_table_2: .dword (DRAM_BASE/RISCV_PGSIZE << PTE_PPN_SHIFT) | PTE_V | PTE_U | PTE_R | PTE_X | PTE_W | PTE_A
 
 RVTEST_DATA_END
-- 
2.30.2