126 lines
3.8 KiB
C
126 lines
3.8 KiB
C
#include "types.h"
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#include "defs.h"
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#include "param.h"
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#include "memlayout.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 enterothers(void);
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static void mpmain(void) __attribute__((noreturn));
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extern pde_t *kpgdir;
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// Bootstrap processor starts running C code here.
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// Allocate a real stack and switch to it, first
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// doing some setup required for memory allocator to work.
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int
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main(void)
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{
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kvmalloc(); // kernel page table
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mpinit(); // collect info about this machine
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lapicinit(mpbcpu());
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seginit(); // set up segments
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cprintf("\ncpu%d: starting xv6\n\n", cpu->id);
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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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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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enterothers(); // start other processors (must come before kinit; must use boot_alloc)
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kinit(); // initialize memory allocator
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userinit(); // first user process (must come after kinit)
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// Finish setting up this processor in mpmain.
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mpmain();
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}
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// Other CPUs jump here from entryother.S.
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static void
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mpboot(void)
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{
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switchkvm();
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seginit();
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lapicinit(cpunum());
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mpmain();
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}
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// Common CPU setup code.
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static void
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mpmain(void)
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{
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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); // tell enterothers() we're up
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scheduler(); // start running processes
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}
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pde_t bootpgdir[];
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// Start the non-boot processors.
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static void
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enterothers(void)
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{
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extern uchar _binary_entryother_start[], _binary_entryother_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.
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// The linker has placed the image of entryother.S in
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// _binary_entryother_start.
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code = p2v(0x7000);
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memmove(code, _binary_entryother_start, (uint)_binary_entryother_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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// Tell entryother.S what stack to use, the address of mpboot and pgdir;
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// We cannot use kpgdir yet, because the AP processor is running in low
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// memory, so we use bootpgdir for the APs too. kalloc can return addresses
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// above 4Mbyte (the machine may have much more physical memory than 4Mbyte), which
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// aren't mapped by bootpgdir, so we must allocate a stack using boot_alloc();
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// This introduces the constraint that xv6 cannot use kalloc until after these
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// last boot_alloc invocations.
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stack = boot_alloc();
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*(void**)(code-4) = stack + KSTACKSIZE;
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*(void**)(code-8) = mpboot;
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*(int**)(code-12) = (void *) v2p(bootpgdir);
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lapicstartap(c->id, v2p(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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// Boot page table used in multiboot.S and entryother.S.
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// Page directories (and page tables), must start on a page boundary,
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// hence the "__aligned__" attribute. Also, because of restrictions
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// related to linking and static initializers, we use "x + PTE_P"
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// here, rather than the more standard "x | PTE_P". Everywhere else
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// you should use "|" to combine flags.
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// Use PTE_PS in page directory entry to enable 4Mbyte pages.
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pte_t dev_pgtable[NPTENTRIES];
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pte_t entry_pgtable[NPTENTRIES];
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__attribute__((__aligned__(PGSIZE)))
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pde_t bootpgdir[NPDENTRIES] = {
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// Map VA's [0, 4MB) to PA's [0, 4MB)
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[0]
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= (0) + PTE_P + PTE_W + PTE_PS,
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// Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
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[KERNBASE>>PDXSHIFT]
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= (0) + PTE_P + PTE_W + PTE_PS,
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};
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//PAGEBREAK!
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// Blank page.
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