修改了ret_from_fork

现在看起来很正常
reticenceji · Jan 25, 2021 · 3a766a0 · 3a766a0
1 parent e0f3a35
commit 3a766a0
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Showing 4 changed files with 27 additions and 24 deletions.
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
@@ -179,9 +179,13 @@ __get_sscratch:
 	ret
 
 #第一个参数 a0 stack
+#第二个参数 a1 kernel_sp
 .globl ret_from_fork
 .type ret_from_fork,@function
 ret_from_fork:
+	csrr sp,sscratch		#继承父进程的用户栈虚拟地址
+	csrw sscratch,a1		#和父进程有不一样的系统栈地址
+
 	ld t0,0x0(a0)
 	add t0,t0,4
 	csrw sepc,t0
@@ -220,10 +224,9 @@ ret_from_fork:
 	ld x4,0xf8(a0)
 	ld x3,0x100(a0)
 	ld ra,0x108(a0)
-	ld sp,0x110(a0)
-	ld x10,0xc8(a0)		#x10就是a0
+	#ld sp,0x110(a0)
+	#ld x10,0xc8(a0)		#x10就是a0
 
-	csrrw sp,sscratch,sp
 	mv a0,zero		#对于子进程fork返回0
 	sret
 

diff --git a/arch/riscv/kernel/fault.c b/arch/riscv/kernel/fault.c
@@ -28,7 +28,7 @@ void do_page_fault(uintptr_t *regs)
         if (current->pid ==1) 
         {
             addr = kmalloc(PAGE_SIZE);
-            create_mapping(page_base, stval & ~0xFFF, PP(addr), PAGE_SIZE, FLAG_R|FLAG_W|FLAG_V|FLAG_U);
+            create_mapping(page_base, stval & ~0xFFF, 0x84000000, PAGE_SIZE, FLAG_R|FLAG_W|FLAG_V|FLAG_U);
         }
         else
             create_mapping(page_base, stval & ~0xFFF, PP(current->user_sp), PAGE_SIZE, FLAG_R|FLAG_W|FLAG_V|FLAG_U);
@@ -40,7 +40,7 @@ void do_page_fault(uintptr_t *regs)
         if (current->pid ==1) 
         {
             addr = kmalloc(PAGE_SIZE);
-            create_mapping(page_base, stval & ~0xFFF, PP(addr), PAGE_SIZE, FLAG_R|FLAG_W|FLAG_V|FLAG_U);
+            create_mapping(page_base, stval & ~0xFFF, 0x84000000, PAGE_SIZE, FLAG_R|FLAG_W|FLAG_V|FLAG_U);
         }
         else
             create_mapping(page_base, stval & ~0xFFF, PP(current->user_sp), PAGE_SIZE, FLAG_R|FLAG_W|FLAG_V|FLAG_U);

diff --git a/arch/riscv/kernel/fork.c b/arch/riscv/kernel/fork.c
@@ -8,7 +8,7 @@
 static void copy_mm(struct task_struct *child);
 static void copy_mmap(struct task_struct *child);
 static struct task_struct* dup_task_struct (struct task_struct *current);
-extern void ret_from_fork(uint64 *stack);
+extern void ret_from_fork(uint64 *stack,uint64* kernel_sp);
 
 /* TODO 为子进程创建它的task_struct(包括Stack的整个Page，并修改部分内容。如果创建失败（NR_TASK）返回NULL，否则返回它的地址 
  * stack内容
@@ -58,6 +58,6 @@ pid_t fork()
 /* TODO 主要功能是调用汇编的ret_from_fork */
 void fork_ret()
 {
-    ret_from_fork(current->stack);
+    ret_from_fork(current->stack,current->thread.sp);
     return;
 }
diff --git a/hello.asm b/hello.asm
@@ -52,23 +52,23 @@ Disassembly of section .text.main:
   80:	fea43023          	sd	a0,-32(s0)
   84:	fb5ff0ef          	jal	ra,38 <fork>
   88:	fea43023          	sd	a0,-32(s0)
-  8c:	f79ff0ef          	jal	ra,4 <getpid>
-  90:	00050793          	mv	a5,a0
-  94:	00010713          	mv	a4,sp
-  98:	00070613          	mv	a2,a4
-  9c:	00078593          	mv	a1,a5
-  a0:	73000513          	li	a0,1840
-  a4:	600000ef          	jal	ra,6a4 <printf>
-  a8:	fe042623          	sw	zero,-20(s0)
-  ac:	0100006f          	j	bc <main+0x50>
-  b0:	fec42783          	lw	a5,-20(s0)
-  b4:	0017879b          	addiw	a5,a5,1
-  b8:	fef42623          	sw	a5,-20(s0)
-  bc:	fec42783          	lw	a5,-20(s0)
-  c0:	0007871b          	sext.w	a4,a5
-  c4:	fff00793          	li	a5,-1
-  c8:	fef714e3          	bne	a4,a5,b0 <main+0x44>
-  cc:	fc1ff06f          	j	8c <main+0x20>
+    8c:	f79ff0ef          	jal	ra,4 <getpid>
+    90:	00050793          	mv	a5,a0
+    94:	00010713          	mv	a4,sp
+    98:	00070613          	mv	a2,a4
+    9c:	00078593          	mv	a1,a5
+    a0:	73000513          	li	a0,1840
+    a4:	600000ef          	jal	ra,6a4 <printf>
+    a8:	fe042623          	sw	zero,-20(s0)
+    ac:	0100006f          	j	bc <main+0x50>
+    b0:	fec42783          	lw	a5,-20(s0)
+    b4:	0017879b          	addiw	a5,a5,1
+    b8:	fef42623          	sw	a5,-20(s0)
+    bc:	fec42783          	lw	a5,-20(s0)
+    c0:	0007871b          	sext.w	a4,a5
+    c4:	fff00793          	li	a5,-1
+    c8:	fef714e3          	bne	a4,a5,b0 <main+0x44>
+    cc:	fc1ff06f          	j	8c <main+0x20>
 
 Disassembly of section .text.putchar: