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-rw-r--r--main.c59
1 files changed, 36 insertions, 23 deletions
diff --git a/main.c b/main.c
index 878ea36..a27c4ff 100644
--- a/main.c
+++ b/main.c
@@ -7,40 +7,45 @@
static void bootothers(void);
static void mpmain(void);
-void jkstack(void) __attribute__((noreturn));
+void jmpkstack(void) __attribute__((noreturn));
void mainc(void);
// 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)
{
mpinit(); // collect info about this machine
lapicinit(mpbcpu());
- ksegment(); // set up segments
- picinit(); // interrupt controller
- ioapicinit(); // another interrupt controller
- consoleinit(); // I/O devices & their interrupts
- uartinit(); // serial port
- pminit(); // discover how much memory there is
- jkstack(); // call mainc() on a properly-allocated stack
+ seginit(); // set up segments
+ kinit(); // initialize memory allocator
+ jmpkstack(); // call mainc() on a properly-allocated stack
}
void
-jkstack(void)
+jmpkstack(void)
{
- char *kstack = kalloc();
- if (!kstack)
- panic("jkstack\n");
- char *top = kstack + PGSIZE;
- asm volatile("movl %0,%%esp" : : "r" (top));
- asm volatile("call mainc");
- panic("jkstack");
+ char *kstack, *top;
+
+ kstack = kalloc();
+ if(kstack == 0)
+ panic("jmpkstack kalloc");
+ top = kstack + PGSIZE;
+ asm volatile("movl %0,%%esp; call mainc" : : "r" (top));
+ panic("jmpkstack");
}
+// Set up hardware and software.
+// Runs only on the boostrap processor.
void
mainc(void)
{
cprintf("\ncpu%d: starting xv6\n\n", cpu->id);
+ picinit(); // interrupt controller
+ ioapicinit(); // another interrupt controller
+ consoleinit(); // I/O devices & their interrupts
+ uartinit(); // serial port
kvmalloc(); // initialize the kernel page table
pinit(); // process table
tvinit(); // trap vectors
@@ -63,17 +68,18 @@ mainc(void)
static void
mpmain(void)
{
- if(cpunum() != mpbcpu()) {
- ksegment();
+ if(cpunum() != mpbcpu()){
+ seginit();
lapicinit(cpunum());
}
vmenable(); // turn on paging
cprintf("cpu%d: starting\n", cpu->id);
idtinit(); // load idt register
- xchg(&cpu->booted, 1);
+ xchg(&cpu->booted, 1); // tell bootothers() we're up
scheduler(); // start running processes
}
+// Start the non-boot processors.
static void
bootothers(void)
{
@@ -82,19 +88,23 @@ bootothers(void)
struct cpu *c;
char *stack;
- // Write bootstrap code to unused memory at 0x7000. The linker has
- // placed the start of bootother.S there.
- code = (uchar *) 0x7000;
+ // Write bootstrap code to unused memory at 0x7000.
+ // The linker has placed the image of bootother.S in
+ // _binary_bootother_start.
+ code = (uchar*)0x7000;
memmove(code, _binary_bootother_start, (uint)_binary_bootother_size);
for(c = cpus; c < cpus+ncpu; c++){
if(c == cpus+cpunum()) // We've started already.
continue;
- // Fill in %esp, %eip and start code on cpu.
+ // Tell bootother.S what stack to use and the address of mpmain;
+ // it expects to find these two addresses stored just before
+ // its first instruction.
stack = kalloc();
*(void**)(code-4) = stack + KSTACKSIZE;
*(void**)(code-8) = mpmain;
+
lapicstartap(c->id, (uint)code);
// Wait for cpu to finish mpmain()
@@ -103,3 +113,6 @@ bootothers(void)
}
}
+//PAGEBREAK!
+// Blank page.
+