88 lines
2.0 KiB
C
88 lines
2.0 KiB
C
#include "elf.h"
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#include "proc.h"
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#include "fs/fs.h"
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#include "cpu/gdt.h"
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#include "cpu/isr.h"
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#include "cpu/memlayout.h"
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#include "kernel/mem.h"
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#include "lib/string.h"
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#include "console.h"
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struct context {
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// matches the behavior of swtch()
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uint32_t edi, esi, ebp, ebx;
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uint32_t eip; // return address for swtch()
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};
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struct kstack {
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uint32_t space[400];
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struct context context;
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registers_t trapframe;
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char bottom[];
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};
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struct task {
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struct taskstate tss;
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struct kstack stack;
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pde_t *pgdir;
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};
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struct vm {
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void *kernel_thread;
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struct task *user_task;
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} vm;
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void trapret();
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void swtch(void** oldstack, void* newstack);
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void run_elf(const char* name) {
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struct stat statbuf;
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if (stat(name, &statbuf) != 0) {
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printk(name);
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printk(": file not found\n");
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return;
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}
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if (!vm.user_task) {
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vm.user_task = kalloc();
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}
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vm.user_task->pgdir = setupkvm();
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allocuvm(vm.user_task->pgdir, USER_BASE, USER_BASE + statbuf.size);
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allocuvm(vm.user_task->pgdir, USER_STACK_BASE - 2 * PGSIZE, USER_STACK_BASE);
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switchuvm(&vm.user_task->tss, vm.user_task->stack.bottom, vm.user_task->pgdir);
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if (read_file(&statbuf, (void*)USER_BASE, 100 << 20) <= 0) {
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printk(name);
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printk(": file not found\n");
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return;
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}
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Elf32_Ehdr *hdr = (void*)USER_BASE;
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struct kstack *u = &vm.user_task->stack;
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memset(u, 0, sizeof(*u));
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u->context.eip = (uint32_t)trapret;
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registers_t *tf = &u->trapframe;
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tf->eip = hdr->e_entry;
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tf->cs = (SEG_UCODE << 3) | DPL_USER;
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tf->ds = (SEG_UDATA << 3) | DPL_USER;
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tf->es = tf->ds;
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tf->fs = tf->ds;
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tf->gs = tf->ds;
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tf->ss = tf->ds;
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tf->eflags = FL_IF;
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tf->useresp = USER_STACK_BASE;
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// initialization done, now switch to the process
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swtch(&vm.kernel_thread, &u->context);
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// process has finished
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}
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_Noreturn void killproc() {
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void* task_stack;
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switchkvm();
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freevm(vm.user_task->pgdir);
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swtch(&task_stack, vm.kernel_thread);
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__builtin_unreachable();
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}
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