From fba067ffed05ffff662cb280df822da2eaf12a0b Mon Sep 17 00:00:00 2001
From: Yunsup Lee <yunsup@cs.berkeley.edu>
Date: Thu, 6 Feb 2014 11:22:32 -0800
Subject: fix recursive interrupts, and more improvements to code

---
 v/entry.S      | 27 ++++++++++++++++++++-------
 v/riscv_test.h |  6 ++++--
 v/vm.c         | 11 +++++------
 3 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/v/entry.S b/v/entry.S
index 662c92f..b4d7a92 100644
--- a/v/entry.S
+++ b/v/entry.S
@@ -68,6 +68,18 @@ save_tf:  # write the trap frame onto the stack
   csrr   x3,cause        # cause
   STORE  x3,35*REGBYTES(x2)
 
+  # get hwacha cause if IRQ_COP
+  # vxcptcause clears hwacha interrupt bit
+
+  bge   x3,x0,1f
+  slli  x3,x3,1 # clearing MSB of cause
+  srli  x3,x3,1 # clearing MSB of cause
+  li    x4,IRQ_COP
+  bne   x3,x4,1f
+  vxcptcause x3
+  STORE  x3,36*REGBYTES(x2)
+1:
+
   ret
 
   .globl  pop_tf
@@ -136,18 +148,18 @@ trap_entry:
   move  a0,x2
   csrr  ra,status
   and   ra,ra,SR_EA
-  beqz  ra, 2f
-  addi  x2,x2,36*REGBYTES
+  beqz  ra,2f
+  addi  x2,x2,37*REGBYTES
 
   # rocket currently doesn't support vxcptsave/vxcptrestore natively
   csrr  x3,impl 
   li    x4,IMPL_ROCKET
   bne   x3,x4,3f
   vgetcfg x4
-  sd    x4,0(x2)
+  STORE x4,0*REGBYTES(x2)
   vgetvl x4
-  sd    x4,8(x2)
-  addi  x2,x2,16
+  STORE x4,1*REGBYTES(x2)
+  addi  x2,x2,2*REGBYTES
   vxcptevac x2
   j     2f
 
@@ -156,8 +168,9 @@ trap_entry:
 2:jal   handle_trap
 
   # when coming from kernel, continue below its stack
-1:li x2,17712
-  sub   x2, sp, x2
+  # we assume vector unit wasn't used in kernel
+1:li    x2,SIZEOF_TRAPFRAME_T_SCALAR
+  sub   x2,sp,x2
   jal   save_tf
   move  sp,x2
   csrs  status,SR_EI
diff --git a/v/riscv_test.h b/v/riscv_test.h
index 26c44f2..685dbac 100644
--- a/v/riscv_test.h
+++ b/v/riscv_test.h
@@ -79,7 +79,8 @@ userstart:                                                              \
 #define PGSHIFT 13
 #define PGSIZE (1 << PGSHIFT)
 
-#define SIZEOF_TRAPFRAME_T 20768
+#define SIZEOF_TRAPFRAME_T 20776
+#define SIZEOF_TRAPFRAME_T_SCALAR 296
 
 #ifndef __ASSEMBLER__
 
@@ -145,7 +146,8 @@ typedef struct
   long epc;
   long badvaddr;
   long cause;
-  long evac[2560];
+  long hwacha_cause;
+  long hwacha_opaque[2560];
 } trapframe_t;
 #endif
 
diff --git a/v/vm.c b/v/vm.c
index a081422..d2f1fd2 100644
--- a/v/vm.c
+++ b/v/vm.c
@@ -150,9 +150,9 @@ static void do_vxcptrestore(long* where)
 static void restore_vector(trapframe_t* tf)
 {
   if (read_csr(impl) == IMPL_ROCKET)
-    do_vxcptrestore(tf->evac);
+    do_vxcptrestore(tf->hwacha_opaque);
   else
-    vxcptrestore(tf->evac);
+    vxcptrestore(tf->hwacha_opaque);
 }
 
 void handle_trap(trapframe_t* tf)
@@ -185,10 +185,9 @@ void handle_trap(trapframe_t* tf)
     handle_fault(tf->badvaddr);
   else if ((long)tf->cause < 0 && (uint8_t)tf->cause == IRQ_COP)
   {
-    long hwacha_cause = vxcptcause();
-    if (hwacha_cause == HWACHA_CAUSE_VF_FAULT_FETCH ||
-        hwacha_cause == HWACHA_CAUSE_FAULT_LOAD ||
-        hwacha_cause == HWACHA_CAUSE_FAULT_STORE)
+    if (tf->hwacha_cause == HWACHA_CAUSE_VF_FAULT_FETCH ||
+        tf->hwacha_cause == HWACHA_CAUSE_FAULT_LOAD ||
+        tf->hwacha_cause == HWACHA_CAUSE_FAULT_STORE)
     {
       long badvaddr = vxcptaux();
       handle_fault(badvaddr);
-- 
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