from richard, fixes for multiprocessor startup, and shutdown.

Reference: /n/atom/patch/applied/pistart
Date: Mon Jan  4 16:21:32 CET 2016
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/bcm/main.c	Mon Jan  4 16:21:18 2016
+++ /sys/src/9/bcm/main.c	Mon Jan  4 16:21:19 2016
@@ -227,20 +227,61 @@
 void
 machinit(void)
 {
-	m->machno = 0;
-	machaddr[m->machno] = m;
+	Mach *m0;
 
 	m->ticks = 1;
 	m->perf.period = 1;
+	m0 = MACHP(0);
+	if (m->machno != 0) {
+		/* synchronise with cpu 0 */
+		m->ticks = m0->ticks;
+		m->fastclock = m0->fastclock;
+		m->delayloop = m0->delayloop;
+	}
 
-	conf.nmach = 1;
+	//machon(m->machno);
+}
 
-	active.machs = 1;
+void
+mach0init(void)
+{
+	m->machno = 0;
+	machaddr[m->machno] = m;
+
+	machinit();
 	active.exiting = 0;
 
 	up = nil;
 }
 
+void
+launchinit(int ncpus)
+{
+	int mach;
+	Mach *mm;
+	PTE *l1;
+
+	if(ncpus > MAXMACH)
+		ncpus = MAXMACH;
+	for(mach = 1; mach < ncpus; mach++){
+		machaddr[mach] = mm = mallocalign(MACHSIZE, MACHSIZE, 0, 0);
+		l1 = mallocalign(L1SIZE, L1SIZE, 0, 0);
+		if(mm == nil || l1 == nil)
+			panic("launchinit");
+		memset(mm, 0, MACHSIZE);
+		mm->machno = mach;
+
+		memmove(l1, m->mmul1, L1SIZE);  /* clone cpu0's l1 table */
+		cachedwbse(l1, L1SIZE);
+		mm->mmul1 = l1;
+		cachedwbse(mm, MACHSIZE);
+
+	}
+	cachedwbse(machaddr, sizeof machaddr);
+	if((mach = startcpus(ncpus)) < ncpus)
+			panic("only %d cpu%s started", mach, mach == 1? "" : "s");
+}
+
 static void
 optionsinit(char* s)
 {
@@ -284,8 +325,9 @@
 	okay(1);
 	m = (Mach*)MACHADDR;
 	memset(edata, 0, end - edata);	/* clear bss */
-	machinit();
+	mach0init();
 	mmuinit1((void*)L1);
+	machon(0);
 
 	optionsinit("/boot/boot boot");
 	fmtinit();
@@ -321,6 +363,7 @@
 	pageinit();
 	swapinit();
 	userinit();
+	launchinit(getncpus());
 	schedinit();
 	assert(0);			/* shouldn't have returned */
 }
@@ -580,9 +623,20 @@
 void
 exit(int code)
 {
+	void (*f)(ulong, ulong, ulong);
+
 	shutdown(code);
 	splfhi();
-	archreboot();
+	if(m->machno == 0)
+		archreboot();
+	else{
+		f = (void*)REBOOTADDR;
+		intrcpushutdown();
+		cacheuwbinv();
+		l2cacheuwbinv();
+		(*f)(0, 0, 0);
+		for(;;){}
+	}
 }
 
 /*
@@ -595,6 +649,14 @@
 	void (*f)(ulong, ulong, ulong);
 
 	writeconf();
+
+	/*
+	 * the boot processor is cpu0.  execute this function on it
+	 * so that the new kernel has the same cpu0.
+	 */
+	if (m->machno != 0)
+		procwired(up, 0);
+
 	shutdown(0);
 
 	/*
--- /sys/src/9/bcm/fns.h	Mon Jan  4 16:21:21 2016
+++ /sys/src/9/bcm/fns.h	Mon Jan  4 16:21:22 2016
@@ -62,6 +62,7 @@
 extern long i2csend(I2Cdev *, void *, long, ulong);
 extern u32int ifsrget(void);
 extern void irqenable(int, void (*)(Ureg*, void*), void*);
+extern void intrcpushutdown(void);
 #define intrenable(i, f, a, b, n) irqenable((i), (f), (a))
 extern void intrsoff(void);
 extern int l2ap(int);