78 lines
1.8 KiB
C
78 lines
1.8 KiB
C
#include "types.h"
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#include "param.h"
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#include "memlayout.h"
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#include "riscv.h"
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#include "spinlock.h"
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#include "proc.h"
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#include "defs.h"
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struct proc proc[NPROC];
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struct proc *initproc;
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// helps ensure that wakeups of wait()ing
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// parents are not lost. helps obey the
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// memory model when using p->parent.
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// must be acquired before any p->lock.
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struct spinlock wait_lock;
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struct proc *allocproc(void);
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// a user program that calls exec("/init")
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// assembled from ../user/initcode.S
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// od -t xC ../user/initcode
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uchar initcode[] = {
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0x17, 0x05, 0x00, 0x00, 0x13, 0x05, 0x45, 0x02,
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0x97, 0x05, 0x00, 0x00, 0x93, 0x85, 0x35, 0x02,
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0x93, 0x08, 0x70, 0x00, 0x73, 0x00, 0x00, 0x00,
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0x93, 0x08, 0x20, 0x00, 0x73, 0x00, 0x00, 0x00,
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0xef, 0xf0, 0x9f, 0xff, 0x2f, 0x69, 0x6e, 0x69,
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0x74, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00
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};
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// Set up first user process.
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void
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userinit(void)
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{
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struct proc *p;
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p = allocproc();
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initproc = p;
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// allocate one user page and copy initcode's instructions
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// and data into it.
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uvmfirst(p->pagetable, initcode, sizeof(initcode));
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p->sz = PGSIZE;
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// prepare for the very first "return" from kernel to user.
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p->trapframe->epc = 0; // user program counter
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p->trapframe->sp = PGSIZE; // user stack pointer
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p->cwd = namei("/");
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p->state = RUNNABLE;
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release(&p->lock);
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}
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// A fork child's very first scheduling by scheduler()
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// will swtch to forkret.
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void
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forkret(void)
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{
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static int first = 1;
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// Still holding p->lock from scheduler.
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release(&myproc()->lock);
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if (first) {
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// File system initialization must be run in the context of a
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// regular process (e.g., because it calls sleep), and thus cannot
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// be run from main().
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first = 0;
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fsinit(ROOTDEV);
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}
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usertrapret();
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}
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