PIC doesn't work after fork(), reinit PIC to fix

thx fleuria

mm/vmm.c

@@ -240,7 +240,7 @@ pde_t *uvm_copy(pte_t *pgdir, uint32_t size){
         printl("uvm_copy: phyaddr: 0x%x -> 0x%x\n", pa, mem);
 
         memcpy((void *)mem, (void *)pa, PAGE_SIZE);
-        vmm_map(pgd, USER_BASE + i, mem, PTE_W | PTE_U | PTE_P);
+        vmm_map(pgd, USER_BASE + i, mem, PTE_R | PTE_U | PTE_P); // TODO (?)
     }
     return pgd;
 }

notes/whyerror.md

@@ -62,3 +62,9 @@ stupid! 错误并不是发生在执行 userland 的时候, 而是因为刚进入
 当要执行的 ISR 的段的 `DPL` < `CPL` 时, CPU 会从 tss 取出对应特权级的 ss 和 esp(这里是 ss0 和 esp0), 然而...
 
 如果段描述符的 Access bit `DC` 置位时, 意味着该段可以被与之相等或更低特权级的段访问(所以就没有取出 tss 的内容了甚至 cs 寄存器的 CPL 也不改变)...但是 kerenl 的页表可是 `PTE_K`的, 所以发生 Page Fault.
+
+#2015-9-6 进入 fork 生成的进程后, PIC 中断不发生, 而第一个进程却不会这样
+不清楚为什么会这样, 只能强制在 `fork_ret` 中再初始化一次, 代码勉强工作.
+// TODO
+
+感谢F叔提供的思路!

proc/init.asm

@@ -11,6 +11,16 @@ __init_start:
     ; push (msg_arg1 - $$) + 0xc0000000
     mov eax, 1
     int 0x80
+    cmp eax, 0
+    jz child
+    jmp $
+child:
+    mov eax, 1
+    int 0x80
+    cmp eax, 0
+    jz child2
+    jmp $
+child2:
     jmp $
 
 msg_arg1:

proc/proc.c

@@ -19,29 +19,52 @@
 // proc
 #include <proc.h>
 
+#include <pic.h>
+
 extern void _isr_stub_ret();
 extern void context_switch(struct context **old, struct context *new);
 
+
 static uint32_t cur_pid = 0;
 static struct proc *initproc = NULL;
 static struct proc ptable[NPROC];
 struct context *cpu_context;
 
 struct proc *proc = NULL;
 
+/* import irq_remap, only use in fork_ret */
+extern void irq_remap();
+/* do not ask me why use irq_remap here, irq didn't work after fork()
+ * and I don't know why, and have to reinit it
+ * thx to fleuria
+ */
 void fork_ret(){
+    static int fst = 1;
+
+    if (fst == 1){
+        fst = 0;
+    } else {
+
+    outb(PIC1_CMD, ICW1_INIT + ICW1_ICW4);    // starts the initialization sequence (in cascade mode)
+    outb(PIC2_CMD, ICW1_INIT + ICW1_ICW4);
+    }
+
     return;
 }
 
-static void print_proc(struct proc *pp){
+void print_proc(struct proc *pp){
     uint32_t pa;
+
     vmm_get_mapping(pp->pgdir, USER_BASE, &pa);
 
-    printl("print_proc:\n    name: %s\n",pp->name);
+    printl("print_proc:\n")
+    printl("    name: %s\n",pp->name);
+    printk("    pid: %d\n", pp->pid);
     printl("    kern_stack: 0x%x\n",pp->kern_stack);
     printl("    pgdir: 0x%x\n",pp->pgdir);
     printl("    phy addr: 0x%x\n", pa);
 }
+
 static struct proc *proc_alloc(){
     struct proc *pp;
     char *tos;
@@ -78,15 +101,15 @@ static struct proc *proc_alloc(){
 
 void proc_init(){
     struct proc *pp;
+    extern char __init_start;
+    extern char __init_end;
+
     printl("proc_userinit: clear ptable\n");
 
     memset(ptable, 0, sizeof(struct proc) * NPROC);
 
     printl("proc_userinit: prepare for init\n");
 
-    extern char __init_start;
-    extern char __init_end;
-
     pp = proc_alloc();
 
     pp->pgdir = (pde_t *)pmm_alloc();
@@ -116,6 +139,7 @@ void proc_init(){
     printl("proc_init: init stack build\n");
 
     strcpy(pp->name, "init");
+
     pp->cwd = p2i("/");
     pp->state = P_RUNABLE;
 
@@ -129,22 +153,23 @@ void scheduler(){
     struct proc *pp;
 
     printl("scheduler: start\n");
+
     for (;;){
         for (pp = &ptable[0]; pp < &ptable[NPROC]; pp++){
             if (pp->state != P_RUNABLE){
                 continue;
             }
-            printl("scheduler: proc `%s` will run\n", pp->name);
-            print_proc(pp);
+            printl("scheduler: proc `%s`(PID: %d) will run\n", pp->name, pp->pid);
 
             printl("scheduler: switch pgdir & set tss\n"); 
             uvm_switch(pp);
             pp->state = P_RUNNING;
 
             proc = pp;
 
+            printl(">>>> context switch\n");
             context_switch(&cpu_context, pp->context);
-            printl("scheduler: return form proc `%s`\n", pp->name);
+            printl("<<<< return form proc `%s`\n", pp->name);
         }
     }
 }
@@ -277,6 +302,7 @@ int fork(){
     child->pgdir = uvm_copy(proc->pgdir, proc->size);
 
     if (child->pgdir == 0){
+        panic("fork:");
         pmm_free((uint32_t)child->kern_stack);
         child->kern_stack = 0;
         child->state = P_UNUSED;
@@ -291,7 +317,6 @@ int fork(){
     *child->fm = *proc->fm; // return form same address
 
     child->fm->eax = 0;
-
     printl("fork: dup opened files\n");
     for (i = 0; i < NOFILE; i++){
         if (proc->ofile[i]){
@@ -300,9 +325,10 @@ int fork(){
     }
 
     child->cwd = idup(proc->cwd);
+
     child->state = P_RUNABLE;
 
-    strncpy(child->name, "init2", 5);
+    strncpy(child->name, proc->name, sizeof(proc->name));
 
     printl("fork: done\n");
     return child->pid;