From ed20aa45fd171ef9e5e81ce08cbe55f2c5739adb Mon Sep 17 00:00:00 2001
From: WangRunji <wangrunji0408@163.com>
Date: Thu, 1 Nov 2018 19:53:30 +0800
Subject: [PATCH] Fix user process bug on RV32.

Set sstatus.SIE = 0 on the initial TrapFrame, to prevent interrupt on switching.
---
 kernel/src/arch/riscv32/boot/trap.asm | 2 +-
 kernel/src/arch/riscv32/context.rs    | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/src/arch/riscv32/boot/trap.asm b/kernel/src/arch/riscv32/boot/trap.asm
index 37afaf11..bf4aba54 100644
--- a/kernel/src/arch/riscv32/boot/trap.asm
+++ b/kernel/src/arch/riscv32/boot/trap.asm
@@ -62,7 +62,7 @@ _save_context:
     lw s1, 32*4(sp)             # s1 = sstatus
     lw s2, 33*4(sp)             # s2 = sepc
     andi s0, s1, 1 << 8
-    bnez s0, _restore_context   # back to U-mode? (sstatus.SPP = 1)
+    bnez s0, _restore_context   # back to S-mode? (sstatus.SPP = 1)
 _save_kernel_sp:
     addi s0, sp, 36*4
     csrw 0x140, s0              # sscratch = kernel-sp
diff --git a/kernel/src/arch/riscv32/context.rs b/kernel/src/arch/riscv32/context.rs
index d1a6d61a..0d412989 100644
--- a/kernel/src/arch/riscv32/context.rs
+++ b/kernel/src/arch/riscv32/context.rs
@@ -30,7 +30,8 @@ impl TrapFrame {
         tf.x[2] = sp;
         tf.sepc = entry_addr;
         tf.sstatus = sstatus::read();
-        tf.sstatus.set_spie(false);     // Enable interrupt
+        tf.sstatus.set_spie(true);
+        tf.sstatus.set_sie(false);
         tf.sstatus.set_spp(sstatus::SPP::User);
         tf
     }