Kernel processes / multitasking

kernel/proc/proc.c

@@ -0,0 +1,159 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include "hal/hal.h"
+#include "vmm/vmm.h"
+#include "spinlock/spinlock.h"
+#include "proc.h"
+#include "dlmalloc/malloc.h"
+#include "pmm/pmm.h"
+#include "util/util.h"
+#include "kprintf.h"
+
+#define PROC_REAPER_FREQ 30
+
+uint64_t pids = 0;
+uint64_t sched_ticks = 0;
+
+Procs PROCS;
+
+Proc *proc_spawnkern(void (*ent)(void), char *name) {
+  Proc *proc = dlmalloc(sizeof(*proc));
+  if (proc == NULL) {
+    return NULL;
+  }
+  hal_memset(proc, 0, sizeof(*proc));
+  hal_memcpy(proc->name, name, PROC_NAME_MAX);
+
+  proc->kern = true;
+
+  uint8_t *sp = (uint8_t *)pmm_alloc(PROC_STACKBLOCKS) + PROC_STACKSIZE;
+
+  #if defined(__x86_64__)
+    proc->platformdata.kstack = sp;
+    hal_memset(&proc->platformdata.trapframe, 0, sizeof(proc->platformdata.trapframe));
+
+    proc->platformdata.trapframe.ss = 0x10;
+    proc->platformdata.trapframe.rsp = (uint64_t)VIRT(sp);
+    proc->platformdata.trapframe.rflags = 0x202;
+    proc->platformdata.trapframe.cs = 0x08;
+    proc->platformdata.trapframe.rip = (uint64_t)ent;
+    proc->platformdata.cr3 = hal_vmm_current_cr3();
+    proc->state = PROC_READY;
+    proc->pid = pids++;
+  #endif
+
+  return proc;
+}
+
+void proc_register(Proc *proc) {
+  spinlock_acquire(&PROCS.spinlock);
+  LL_APPEND(PROCS.procs, proc);
+  spinlock_release(&PROCS.spinlock);
+}
+
+Proc *proc_nextready(void) {
+  Proc *next = PROCS.current->next;
+  Proc *proc = next == NULL ? PROCS.procs : next;
+  return proc;
+}
+
+void proc_sched(void *cpustate) {
+  hal_intr_disable();
+  sched_ticks++;
+
+  if (sched_ticks % PROC_REAPER_FREQ == 0) {
+    Proc *head = PROCS.procs;
+    while (head) {
+      if (head->state == PROC_ZOMBIE) {
+        Proc *zombie = head;
+        head = head->next;
+
+        LL_REMOVE(PROCS.procs, zombie);
+        pmm_free((uintptr_t)(zombie->platformdata.kstack - PROC_STACKSIZE), PROC_STACKBLOCKS);
+        dlfree(zombie);
+      } else {
+        head = head->next;
+      }
+    }
+  }
+
+  #if defined(__x86_64__)
+    IntrStackFrame *frame = cpustate;
+
+    PROCS.current->platformdata.trapframe = *frame;
+    PROCS.current->platformdata.fsbase = hal_cpu_rdmsr(HAL_CPU_FSBASE);
+  #endif
+    
+  PROCS.current = proc_nextready();
+  PROCS.current->state = PROC_RUNNING;
+
+  #if defined(__x86_64__)
+    hal_cpu_wrmsr(HAL_CPU_FSBASE, PROCS.current->platformdata.fsbase);
+    hal_switchproc(&PROCS.current->platformdata.trapframe, (void *)PROCS.current->platformdata.cr3);
+  #endif
+}
+
+void proc_kill(Proc *proc) {
+  proc->state = PROC_ZOMBIE;
+}
+
+void proc_killself(void) {
+  spinlock_acquire(&PROCS.spinlock);
+  Proc *proc = PROCS.current;
+  proc_kill(proc);
+  spinlock_release(&PROCS.spinlock);
+}
+
+void proc_idle(void) {
+  for(;;) {
+    // .
+  }
+}
+
+int a = 0;
+
+void proc_print(void) {
+  for (;;) {
+    for (volatile size_t i = 0; i < 0x1000000; i++) {
+    }
+    
+    if (a == 10) {
+      proc_killself();
+      for(;;);
+    }
+    kprintf("A");
+    a++;
+  }
+}
+
+int b = 0;
+
+void proc_print2(void) {
+  for (;;) {
+    for (volatile size_t i = 0; i < 0x1000000; i++) {
+    }
+    
+    if (b == 20) {
+      proc_killself();
+      for(;;);
+    }
+    kprintf("B");
+    b++;
+  }
+}
+
+void proc_init(void) {
+  spinlock_init(&PROCS.spinlock);
+  PROCS.procs = NULL;
+
+  Proc *idle = proc_spawnkern(&proc_idle, "kIDLE");
+  proc_register(idle);
+  PROCS.current = idle;
+
+  proc_register(proc_spawnkern(&proc_print, "print"));
+  proc_register(proc_spawnkern(&proc_print2, "print"));
+
+  #if defined(__x86_64__)
+    hal_switchproc(&PROCS.current->platformdata.trapframe, (void *)PROCS.current->platformdata.cr3);
+  #endif
+}

kernel/proc/proc.h

@@ -0,0 +1,44 @@
+#ifndef PROC_PROC_H_
+#define PROC_PROC_H_
+
+#include <stdint.h>
+#include "hal/hal.h"
+#include "vmm/vmm.h"
+#include "spinlock/spinlock.h"
+#include "bitmap/bitmap.h"
+
+#define PROC_NAME_MAX 0x100
+
+#define PROC_STACKBLOCKS 32
+#define PROC_STACKSIZE (PROC_STACKBLOCKS * BITMAP_BLOCK_SIZE)
+
+enum {
+  PROC_READY,
+  PROC_RUNNING,
+  PROC_ZOMBIE,
+  PROC_WAITING,
+};
+
+typedef struct Proc {
+  struct Proc *next;
+  uint64_t pid;
+  char name[PROC_NAME_MAX];
+  ProcPlatformData platformdata;
+  uint8_t state;
+  VasRange *vas;
+  bool kern;
+} Proc;
+
+typedef struct {
+  SpinLock spinlock;
+  Proc *procs;
+  Proc *current;
+} Procs;
+
+extern Procs PROCS;
+
+void proc_init(void);
+Proc *proc_spawnkern(void (*ent)(void), char *name);
+void proc_sched(void *cpustate);
+
+#endif // PROC_PROC_H_