plan9fox/sys/src/9/pc/main.c

#include	"u.h"
#include	"tos.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"io.h"
#include	"../port/pci.h"
#include	"ureg.h"
#include	"pool.h"
#include	"rebootcode.i"

Mach *m;
Conf conf;

int delaylink;
int idle_spin;

extern void (*i8237alloc)(void);
extern void bootscreeninit(void);
extern void multibootdebug(void);

void
main(void)
{
	mach0init();
	bootargsinit();
	trapinit0();
	ioinit();
	i8250console();
	quotefmtinstall();
	screeninit();
	print("\nPlan 9\n");
	cpuidentify();
	meminit0();
	archinit();
	if(arch->clockinit)
		arch->clockinit();
	meminit();
	ramdiskinit();
	confinit();
	xinit();
	if(i8237alloc != nil)
		i8237alloc();
	pcicfginit();
	bootscreeninit();
	trapinit();
	printinit();
	cpuidprint();
	mmuinit();
	if(arch->intrinit)	/* launches other processors on an mp */
		arch->intrinit();
	timersinit();
	mathinit();
	if(arch->clockenable)
		arch->clockenable();
	procinit0();
	initseg();
	if(delaylink){
		bootlinks();
	}else
		links();
	chandevreset();
	pageinit();
	userinit();
	schedinit();
}

void
mach0init(void)
{
	conf.nmach = 1;
	MACHP(0) = (Mach*)CPU0MACH;
	m->pdb = (ulong*)CPU0PDB;
	m->gdt = (Segdesc*)CPU0GDT;

	machinit();

	active.machs[0] = 1;
	active.exiting = 0;
}

void
machinit(void)
{
	int machno;
	ulong *pdb;
	Segdesc *gdt;

	machno = m->machno;
	pdb = m->pdb;
	gdt = m->gdt;
	memset(m, 0, sizeof(Mach));
	m->machno = machno;
	m->pdb = pdb;
	m->gdt = gdt;
	m->perf.period = 1;

	/*
	 * For polled uart output at boot, need
	 * a default delay constant. 100000 should
	 * be enough for a while. Cpuidentify will
	 * calculate the real value later.
	 */
	m->loopconst = 100000;
}

void
init0(void)
{
	char buf[2*KNAMELEN], **sp;

	chandevinit();

	if(!waserror()){
		snprint(buf, sizeof(buf), "%s %s", arch->id, conffile);
		ksetenv("terminal", buf, 0);
		ksetenv("cputype", "386", 0);
		if(cpuserver)
			ksetenv("service", "cpu", 0);
		else
			ksetenv("service", "terminal", 0);
		setconfenv();
		poperror();
	}
	kproc("alarm", alarmkproc, 0);

	sp = (char**)(USTKTOP - sizeof(Tos) - 8 - sizeof(sp[0])*4);
	sp[3] = sp[2] = nil;
	strcpy(sp[1] = (char*)&sp[4], "boot");
	sp[0] = nil;
	touser(sp);
}

void
confinit(void)
{
	char *p;
	int i, userpcnt;
	ulong kpages;

	if(p = getconf("service")){
		if(strcmp(p, "cpu") == 0)
			cpuserver = 1;
		else if(strcmp(p,"terminal") == 0)
			cpuserver = 0;
	}

	if(p = getconf("*kernelpercent"))
		userpcnt = 100 - strtol(p, 0, 0);
	else
		userpcnt = 0;

	conf.npage = 0;
	for(i=0; i<nelem(conf.mem); i++)
		conf.npage += conf.mem[i].npage;

	conf.nproc = 100 + ((conf.npage*BY2PG)/MB)*5;
	if(cpuserver)
		conf.nproc *= 3;
	if(conf.nproc > 2000)
		conf.nproc = 2000;
	conf.nimage = 200;
	conf.nswap = conf.nproc*80;
	conf.nswppo = 4096;

	if(cpuserver) {
		if(userpcnt < 10)
			userpcnt = 70;
		kpages = conf.npage - (conf.npage*userpcnt)/100;
		conf.nimage = conf.nproc;

		/*
		 * Hack for the big boys. Only good while physmem < 4GB.
		 * Give the kernel fixed max + enough to allocate the
		 * page pool.
		 * This is an overestimate as conf.upages < conf.npages.
		 * The patch of nimage is a band-aid, scanning the whole
		 * page list in imagereclaim just takes too long.
		 */
		if(getconf("*imagemaxmb") == 0)
		if(kpages > (64*MB + conf.npage*sizeof(Page))/BY2PG){
			kpages = (64*MB + conf.npage*sizeof(Page))/BY2PG;
			kpages += (conf.nproc*KSTACK)/BY2PG;
		}
	} else {
		if(userpcnt < 10) {
			if(conf.npage*BY2PG < 16*MB)
				userpcnt = 50;
			else
				userpcnt = 60;
		}
		kpages = conf.npage - (conf.npage*userpcnt)/100;

		/*
		 * Make sure terminals with low memory get at least
		 * 4MB on the first Image chunk allocation.
		 */
		if(conf.npage*BY2PG < 16*MB)
			imagmem->minarena = 4*MB;
	}

	/*
	 * can't go past the end of virtual memory
	 * (ulong)-KZERO is 2^32 - KZERO
	 */
	if(kpages > ((ulong)-KZERO)/BY2PG)
		kpages = ((ulong)-KZERO)/BY2PG;

	conf.upages = conf.npage - kpages;
	conf.ialloc = (kpages/2)*BY2PG;

	/*
	 * Guess how much is taken by the large permanent
	 * datastructures. Mntcache and Mntrpc are not accounted for.
	 */
	kpages *= BY2PG;
	kpages -= conf.upages*sizeof(Page)
		+ conf.nproc*sizeof(Proc)
		+ conf.nimage*sizeof(Image)
		+ conf.nswap
		+ conf.nswppo*sizeof(Page*);
	mainmem->maxsize = kpages;

	/*
	 * the dynamic allocation will balance the load properly,
	 * hopefully. be careful with 32-bit overflow.
	 */
	imagmem->maxsize = kpages - (kpages/10);
	if(p = getconf("*imagemaxmb")){
		imagmem->maxsize = strtol(p, nil, 0)*MB;
		if(imagmem->maxsize > mainmem->maxsize)
			imagmem->maxsize = mainmem->maxsize;
	}
}

void
procsetup(Proc *p)
{
	fpuprocsetup(p);

	memset(p->gdt, 0, sizeof(p->gdt));
	p->nldt = 0;
	
	/* clear debug registers */
	memset(p->dr, 0, sizeof(p->dr));
	if(m->dr7 != 0){
		m->dr7 = 0;
		putdr7(0);
	}
}

void
procfork(Proc *p)
{
	/* inherit user descriptors */
	memmove(p->gdt, up->gdt, sizeof(p->gdt));

	/* copy local descriptor table */
	if(up->ldt != nil && up->nldt > 0){
		p->ldt = smalloc(sizeof(Segdesc) * up->nldt);
		memmove(p->ldt, up->ldt, sizeof(Segdesc) * up->nldt);
		p->nldt = up->nldt;
	}

	fpuprocfork(p);
}

void
procrestore(Proc *p)
{
	if(p->dr[7] != 0){
		m->dr7 = p->dr[7];
		putdr(p->dr);
	}
	
	if(p->vmx != nil)
		vmxprocrestore(p);

	fpuprocrestore(p);
}

/*
 *  Save the mach dependent part of the process state.
 */
void
procsave(Proc *p)
{
	/* we could just always putdr7(0) but accessing DR7 might be slow in a VM */
	if(m->dr7 != 0){
		m->dr7 = 0;
		putdr7(0);
	}
	if(p->state == Moribund)
		p->dr[7] = 0;

	fpuprocsave(p);

	/*
	 * While this processor is in the scheduler, the process could run
	 * on another processor and exit, returning the page tables to
	 * the free list where they could be reallocated and overwritten.
	 * When this processor eventually has to get an entry from the
	 * trashed page tables it will crash.
	 *
	 * If there's only one processor, this can't happen.
	 * You might think it would be a win not to do this in that case,
	 * especially on VMware, but it turns out not to matter.
	 */
	mmuflushtlb(PADDR(m->pdb));
}

static void
rebootjump(uintptr entry, uintptr code, ulong size)
{
	void (*f)(uintptr, uintptr, ulong);
	ulong *pdb;

	splhi();
	arch->introff();

	/*
	 * Modify the machine page table to directly map the low 4MB of memory
	 * This allows the reboot code to turn off the page mapping
	 */
	pdb = m->pdb;
	pdb[PDX(0)] = pdb[PDX(KZERO)];
	mmuflushtlb(PADDR(pdb));

	/* setup reboot trampoline function */
	f = (void*)REBOOTADDR;
	memmove(f, rebootcode, sizeof(rebootcode));

	/* off we go - never to return */
	coherence();
	(*f)(entry, code, size);
	for(;;);
}


void
exit(int)
{
	cpushutdown();
	if(m->machno)
		rebootjump(0, 0, 0);
	arch->reset();
}

void
reboot(void *entry, void *code, ulong size)
{
	writeconf();
	vmxshutdown();

	/*
	 * the boot processor is cpu0.  execute this function on it
	 * so that the new kernel has the same cpu0.  this only matters
	 * because the hardware has a notion of which processor was the
	 * boot processor and we look at it at start up.
	 */
	if (m->machno != 0) {
		procwired(up, 0);
		sched();
	}
	cpushutdown();
	delay(1000);
	splhi();

	/* turn off buffered serial console */
	serialoq = nil;

	/* shutdown devices */
	chandevshutdown();

	/* disable pci devices */
	pcireset();

	rebootjump((ulong)entry & ~0xF0000000UL, PADDR(code), size);
}