Initial Upload

2022-12-06 11:49:47 +00:00
commit 0ee33aaa97
274 changed files with 60109 additions and 0 deletions
--- a/trap.c
+++ b/trap.c
@ -0,0 +1,111 @@
+#include "types.h"
+#include "defs.h"
+#include "param.h"
+#include "memlayout.h"
+#include "mmu.h"
+#include "proc.h"
+#include "x86.h"
+#include "traps.h"
+#include "spinlock.h"
+
+// Interrupt descriptor table (shared by all CPUs).
+struct gatedesc idt[256];
+extern uint vectors[];  // in vectors.S: array of 256 entry pointers
+struct spinlock tickslock;
+uint ticks;
+
+void tvinit(void) {
+    int i;
+
+    for (i = 0; i < 256; i++) {
+        SETGATE(idt[i], 0, SEG_KCODE << 3, vectors[i], 0);
+    }
+    SETGATE(idt[T_SYSCALL], 1, SEG_KCODE << 3, vectors[T_SYSCALL], DPL_USER);
+
+    initlock(&tickslock, "time");
+}
+
+void idtinit(void) {
+    lidt(idt, sizeof(idt));
+}
+
+void trap(struct trapframe *tf) {
+    if (tf->trapno == T_SYSCALL) {
+        if (myproc()->killed) {
+            exit();
+        }
+        myproc()->tf = tf;
+        syscall();
+        if (myproc()->killed) {
+            exit();
+        }
+        return;
+    }
+
+    switch (tf->trapno) {
+        case T_IRQ0 + IRQ_TIMER:
+            if (cpuid() == 0) {
+                acquire(&tickslock);
+                ticks++;
+                wakeup(&ticks);
+                release(&tickslock);
+            }
+            lapiceoi();
+            break;
+        case T_IRQ0 + IRQ_IDE:
+            ideintr();
+            lapiceoi();
+            break;
+        case T_IRQ0 + IRQ_IDE + 1:
+            // Bochs generates spurious IDE1 interrupts.
+            break;
+        case T_IRQ0 + IRQ_KBD:
+            kbdintr();
+            lapiceoi();
+            break;
+        case T_IRQ0 + IRQ_COM1:
+            uartintr();
+            lapiceoi();
+            break;
+        case T_IRQ0 + 7:
+        case T_IRQ0 + IRQ_SPURIOUS:
+            cprintf("cpu%d: spurious interrupt at %x:%x\n",
+                    cpuid(), tf->cs, tf->eip);
+            lapiceoi();
+            break;
+
+    
+        default:
+            if (myproc() == 0 || (tf->cs & 3) == 0) {
+                // In kernel, it must be our mistake.
+                cprintf("unexpected trap %d from cpu %d eip %x (cr2=0x%x)\n",
+                        tf->trapno, cpuid(), tf->eip, rcr2());
+                panic("trap");
+            }
+            // In user space, assume process misbehaved.
+            cprintf("pid %d %s: trap %d err %d on cpu %d "
+                    "eip 0x%x addr 0x%x--kill proc\n",
+                    myproc()->pid, myproc()->name, tf->trapno,
+                    tf->err, cpuid(), tf->eip, rcr2());
+            myproc()->killed = 1;
+    }
+
+    // Force process exit if it has been killed and is in user space.
+    // (If it is still executing in the kernel, let it keep running
+    // until it gets to the regular system call return.)
+    if (myproc() && myproc()->killed && (tf->cs & 3) == DPL_USER) {
+        exit();
+    }
+
+    // Force process to give up CPU on clock tick.
+    // If interrupts were on while locks held, would need to check nlock.
+    if (myproc() && myproc()->state == RUNNING &&
+        tf->trapno == T_IRQ0 + IRQ_TIMER) {
+        yield();
+    }
+
+    // Check if the process has been killed since we yielded
+    if (myproc() && myproc()->killed && (tf->cs & 3) == DPL_USER) {
+        exit();
+    }
+}