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Diffstat (limited to 'main.c')
-rw-r--r--main.c42
1 files changed, 27 insertions, 15 deletions
diff --git a/main.c b/main.c
index 78cd334..a6088cb 100644
--- a/main.c
+++ b/main.c
@@ -7,7 +7,8 @@
static void bootothers(void);
static void mpmain(void);
-void jkstack(void) __attribute__((noreturn));
+void jkstack(void) __attribute__((noreturn));
+void mainc(void);
// Bootstrap processor starts running C code here.
int
@@ -15,21 +16,32 @@ main(void)
{
mpinit(); // collect info about this machine
lapicinit(mpbcpu());
- ksegment();
+ ksegment(); // set up segments
picinit(); // interrupt controller
ioapicinit(); // another interrupt controller
consoleinit(); // I/O devices & their interrupts
uartinit(); // serial port
- pminit(); // physical memory for kernel
- jkstack(); // Jump to mainc on a proper-allocated kernel stack
+ pminit(); // discover how much memory there is
+ jkstack(); // call mainc() on a properly-allocated stack
+}
+
+void
+jkstack(void)
+{
+ char *kstack = kalloc(PGSIZE);
+ if (!kstack)
+ panic("jkstack\n");
+ char *top = kstack + PGSIZE;
+ asm volatile("movl %0,%%esp" : : "r" (top));
+ asm volatile("call mainc");
+ panic("jkstack");
}
void
mainc(void)
{
- cprintf("cpus %p cpu %p\n", cpus, cpu);
cprintf("\ncpu%d: starting xv6\n\n", cpu->id);
- kvmalloc(); // allocate the kernel page table
+ kvmalloc(); // initialze the kernel page table
pinit(); // process table
tvinit(); // trap vectors
binit(); // buffer cache
@@ -45,22 +57,21 @@ mainc(void)
mpmain();
}
-// Bootstrap processor gets here after setting up the hardware.
-// Additional processors start here.
+// Common CPU setup code.
+// Bootstrap CPU comes here from mainc().
+// Other CPUs jump here from bootother.S.
static void
mpmain(void)
{
if(cpunum() != mpbcpu()) {
ksegment();
- cprintf("other cpu\n");
lapicinit(cpunum());
}
- vminit(); // Run with paging on each processor
- cprintf("cpu%d: mpmain\n", cpu->id);
- idtinit();
+ vminit(); // turn on paging
+ cprintf("cpu%d: starting\n", cpu->id);
+ idtinit(); // load idt register
xchg(&cpu->booted, 1);
- cprintf("cpu%d: scheduling\n", cpu->id);
- scheduler();
+ scheduler(); // start running processes
}
static void
@@ -75,6 +86,7 @@ bootothers(void)
// placed the start of bootother.S there.
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;
@@ -85,7 +97,7 @@ bootothers(void)
*(void**)(code-8) = mpmain;
lapicstartap(c->id, (uint)code);
- // Wait for cpu to get through bootstrap.
+ // Wait for cpu to finish mpmain()
while(c->booted == 0)
;
}