1afc9d3fca
find out the hard way why user and kernel must have separate segment descriptors
106 lines
2.6 KiB
C
106 lines
2.6 KiB
C
#include "types.h"
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#include "defs.h"
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#include "param.h"
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#include "mmu.h"
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#include "proc.h"
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#include "x86.h"
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static void bootothers(void);
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static void mpmain(void);
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void jkstack(void) __attribute__((noreturn));
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void mainc(void);
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// Bootstrap processor starts running C code here.
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int
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main(void)
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{
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mpinit(); // collect info about this machine
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lapicinit(mpbcpu());
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ksegment(); // set up segments
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picinit(); // interrupt controller
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ioapicinit(); // another interrupt controller
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consoleinit(); // I/O devices & their interrupts
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uartinit(); // serial port
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pminit(); // discover how much memory there is
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jkstack(); // call mainc() on a properly-allocated stack
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}
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void
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jkstack(void)
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{
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char *kstack = kalloc(PGSIZE);
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if (!kstack)
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panic("jkstack\n");
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char *top = kstack + PGSIZE;
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asm volatile("movl %0,%%esp" : : "r" (top));
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asm volatile("call mainc");
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panic("jkstack");
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}
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void
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mainc(void)
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{
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cprintf("\ncpu%d: starting xv6\n\n", cpu->id);
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kvmalloc(); // initialze the kernel page table
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pinit(); // process table
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tvinit(); // trap vectors
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binit(); // buffer cache
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fileinit(); // file table
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iinit(); // inode cache
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ideinit(); // disk
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if(!ismp)
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timerinit(); // uniprocessor timer
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userinit(); // first user process
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bootothers(); // start other processors
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// Finish setting up this processor in mpmain.
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mpmain();
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}
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// Common CPU setup code.
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// Bootstrap CPU comes here from mainc().
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// Other CPUs jump here from bootother.S.
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static void
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mpmain(void)
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{
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if(cpunum() != mpbcpu()) {
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ksegment();
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lapicinit(cpunum());
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}
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vminit(); // turn on paging
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cprintf("cpu%d: starting\n", cpu->id);
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idtinit(); // load idt register
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xchg(&cpu->booted, 1);
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scheduler(); // start running processes
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}
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static void
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bootothers(void)
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{
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extern uchar _binary_bootother_start[], _binary_bootother_size[];
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uchar *code;
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struct cpu *c;
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char *stack;
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// Write bootstrap code to unused memory at 0x7000. The linker has
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// placed the start of bootother.S there.
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code = (uchar *) 0x7000;
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memmove(code, _binary_bootother_start, (uint)_binary_bootother_size);
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for(c = cpus; c < cpus+ncpu; c++){
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if(c == cpus+cpunum()) // We've started already.
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continue;
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// Fill in %esp, %eip and start code on cpu.
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stack = kalloc(KSTACKSIZE);
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*(void**)(code-4) = stack + KSTACKSIZE;
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*(void**)(code-8) = mpmain;
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lapicstartap(c->id, (uint)code);
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// Wait for cpu to finish mpmain()
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while(c->booted == 0)
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;
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}
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}
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