Initial Upload

main.c

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+#include "types.h"
+#include "defs.h"
+#include "param.h"
+#include "memlayout.h"
+#include "mmu.h"
+#include "proc.h"
+#include "x86.h"
+
+static void startothers(void);
+static void mpmain(void)  __attribute__((noreturn));
+extern pde_t *kpgdir;
+extern char end[]; // first address after kernel loaded from ELF file
+
+// Bootstrap processor starts running C code here.
+// Allocate a real stack and switch to it, first
+// doing some setup required for memory allocator to work.
+
+int main(void) {
+    kinit1(end, P2V(4 * 1024 * 1024)); // phys page allocator
+    kvmalloc();      // kernel page table
+    mpinit();        // detect other processors
+    lapicinit();     // interrupt controller
+    seginit();       // segment descriptors
+    picinit();       // disable pic
+    ioapicinit();    // another interrupt controller
+    consoleinit();   // console hardware
+    uartinit();      // serial port
+    pinit();         // process table
+    tvinit();        // trap vectors
+    binit();         // buffer cache
+    fileinit();      // file table
+    ideinit();       // disk
+    startothers();   // start other processors
+    kinit2(P2V(4 * 1024 * 1024), P2V(PHYSTOP)); // must come after startothers()
+    userinit();      // first user process
+    mpmain();        // finish this processor's setup
+}
+
+// Other CPUs jump here from entryother.S.
+static void mpenter(void)  {
+    switchkvm();
+    seginit();
+    lapicinit();
+    mpmain();
+}
+
+// Common CPU setup code.
+static void mpmain(void) {
+    cprintf("cpu%d: starting %d\n", cpuid(), cpuid());
+    idtinit();       // load idt register
+    xchg(&(mycpu()->started), 1); // tell startothers() we're up
+    scheduler();     // start running processes
+}
+
+pde_t entrypgdir[];  // For entry.S
+
+// Start the non-boot (AP) processors.
+static void startothers(void) {
+    extern uchar _binary_entryother_start[], _binary_entryother_size[];
+    uchar *code;
+    struct cpu *c;
+    char *stack;
+
+    // Write entry code to unused memory at 0x7000.
+    // The linker has placed the image of entryother.S in
+    // _binary_entryother_start.
+    code = P2V(0x7000);
+    memmove(code, _binary_entryother_start, (uint)_binary_entryother_size);
+
+    for (c = cpus; c < cpus + ncpu; c++) {
+        if (c == mycpu()) { // We've started already.
+            continue;
+        }
+
+        // Tell entryother.S what stack to use, where to enter, and what
+        // pgdir to use. We cannot use kpgdir yet, because the AP processor
+        // is running in low  memory, so we use entrypgdir for the APs too.
+        stack = kalloc();
+        *(void**)(code - 4) = stack + KSTACKSIZE;
+        *(void(**)(void))(code - 8) = mpenter;
+        *(int**)(code - 12) = (void *) V2P(entrypgdir);
+
+        lapicstartap(c->apicid, V2P(code));
+
+        // wait for cpu to finish mpmain()
+        while (c->started == 0) {
+            ;
+        }
+    }
+}
+
+// The boot page table used in entry.S and entryother.S.
+// Page directories (and page tables) must start on page boundaries,
+// hence the __aligned__ attribute.
+// PTE_PS in a page directory entry enables 4Mbyte pages.
+
+__attribute__((__aligned__(PGSIZE)))
+pde_t entrypgdir[NPDENTRIES] = {
+    // Map VA's [0, 4MB) to PA's [0, 4MB)
+    [0] = (0) | PTE_P | PTE_W | PTE_PS,
+    // Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
+    [KERNBASE >> PDXSHIFT] = (0) | PTE_P | PTE_W | PTE_PS,
+};
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