import xen 32 bit paravirtual kernel from /n/sources/xen.

1 files changed, 801 insertions, 0 deletions

diff --git a/sys/src/9/xen/main.c b/sys/src/9/xen/main.c
new file mode 100644
index 000000000..966b39997
--- /dev/null
+++ b/sys/src/9/xen/main.c
@@ -0,0 +1,801 @@
+#include	"u.h"
+#include	"../port/lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"io.h"
+#include	"ureg.h"
+#include	"init.h"
+#include	"pool.h"
+#include	"reboot.h"
+#include	<tos.h>
+
+Mach *m;
+
+#define BOOTARGS	(xenstart->cmd_line)
+#define	BOOTARGSLEN	(sizeof xenstart->cmd_line)
+#define	MAXCONF		64
+
+enum {
+	/* space for syscall args, return PC, top-of-stack struct */
+	Ustkheadroom	= sizeof(Sargs) + sizeof(uintptr) + sizeof(Tos),
+};
+
+char bootdisk[KNAMELEN];
+Conf conf;
+char *confname[MAXCONF];
+char *confval[MAXCONF];
+int nconf;
+uchar *sp;	/* user stack of init proc */
+int idle_spin;
+
+static void
+options(void)
+{
+	long i, n;
+	char *cp, *line[MAXCONF], *p, *q;
+
+	/*
+	 *  parse configuration args from dos file plan9.ini
+	 */
+	cp = BOOTARGS;	/* where b.com leaves its config */
+	cp[BOOTARGSLEN-1] = 0;
+
+	/*
+	 * Strip out '\r', change '\t' -> ' '.
+	 */
+	p = cp;
+	for(q = cp; *q; q++){
+		if(*q == '\r')
+			continue;
+		if(*q == '\t')
+			*q = ' ';
+		*p++ = *q;
+	}
+	*p = 0;
+
+	n = getfields(cp, line, MAXCONF, 1, "\n");
+	for(i = 0; i < n; i++){
+		if(*line[i] == '#')
+			continue;
+		cp = strchr(line[i], '=');
+		if(cp == nil)
+			continue;
+		*cp++ = '\0';
+		confname[nconf] = line[i];
+		confval[nconf] = cp;
+		nconf++;
+	}
+}
+
+void
+main(void)
+{
+	mach0init();
+	options();
+	quotefmtinstall();
+	xenconsinit();
+
+	//consdebug = rdb;
+	print("\nPlan 9 (%s)\n", xenstart->magic);
+
+	cpuidentify();
+	// meminit() is not for us
+	confinit();
+	archinit();
+	xinit();
+	trapinit();
+	printinit();
+	cpuidprint();
+	mmuinit();
+	if(arch->intrinit)	/* launches other processors on an mp */
+		arch->intrinit();
+	timersinit();
+	mathinit();
+	kbdenable();
+	xengrantinit();
+	if(arch->clockenable)
+		arch->clockenable();
+	procinit0();
+	initseg();
+
+	links();
+//	conf.monitor = 1;
+	chandevreset();
+	pageinit();
+
+	swapinit();
+	userinit();
+	active.thunderbirdsarego = 1;
+	schedinit();
+}
+
+void
+mach0init(void)
+{
+	m = (Mach*)MACHADDR;
+	m->machno = 0;
+	conf.nmach = 1;
+	MACHP(0) = (Mach*)CPU0MACH;
+	m->pdb = (ulong*)xenstart->pt_base;
+#ifdef NOT
+	m->gdt = (Segdesc*)CPU0GDT;
+#endif
+
+	machinit();
+
+	active.machs = 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;
+	m->cpumhz = 1000;				// XXX! 
+
+	HYPERVISOR_shared_info = (shared_info_t*)mmumapframe(XENSHARED, (xenstart->shared_info)>>PGSHIFT);
+	
+	// XXX m->shared = &HYPERVISOR_shared_info->vcpu_data[m->machno];
+}
+
+void
+init0(void)
+{
+	int i;
+	char buf[2*KNAMELEN];
+
+	up->nerrlab = 0;
+
+	spllo();
+
+	/*
+	 * These are o.k. because rootinit is null.
+	 * Then early kproc's will have a root and dot.
+	 */
+	up->slash = namec("#/", Atodir, 0, 0);
+	pathclose(up->slash->path);
+	up->slash->path = newpath("/");
+	up->dot = cclone(up->slash);
+
+	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);
+		ksetenv("readparts", "1", 0);
+		for(i = 0; i < nconf; i++){
+			if(confname[i][0] != '*')
+				ksetenv(confname[i], confval[i], 0);
+			ksetenv(confname[i], confval[i], 1);
+		}
+		poperror();
+	}
+
+	kproc("alarm", alarmkproc, 0);
+	touser(sp);
+}
+
+void
+userinit(void)
+{
+	Proc *p;
+	Segment *s;
+	KMap *k;
+	Page *pg;
+
+	p = newproc();
+	p->pgrp = newpgrp();
+	p->egrp = smalloc(sizeof(Egrp));
+	p->egrp->ref = 1;
+	p->fgrp = dupfgrp(nil);
+	p->rgrp = newrgrp();
+	p->procmode = 0640;
+
+	kstrdup(&eve, "");
+	kstrdup(&p->text, "*init*");
+	kstrdup(&p->user, eve);
+
+	p->fpstate = FPinit;
+	fpoff();
+
+	/*
+	 * Kernel Stack
+	 *
+	 * N.B. make sure there's enough space for syscall to check
+	 *	for valid args and 
+	 *	4 bytes for gotolabel's return PC
+	 */
+	p->sched.pc = (ulong)init0;
+	p->sched.sp = (ulong)p->kstack+KSTACK-(sizeof(Sargs)+BY2WD);
+
+	/*
+	 * User Stack
+	 */
+	s = newseg(SG_STACK, USTKTOP-USTKSIZE, USTKSIZE/BY2PG);
+	p->seg[SSEG] = s;
+	pg = newpage(1, 0, USTKTOP-BY2PG);
+	segpage(s, pg);
+	k = kmap(pg);
+	bootargs(VA(k));
+	kunmap(k);
+
+	/*
+	 * Text
+	 */
+	s = newseg(SG_TEXT, UTZERO, 1);
+	s->flushme++;
+	p->seg[TSEG] = s;
+	pg = newpage(1, 0, UTZERO);
+	memset(pg->cachectl, PG_TXTFLUSH, sizeof(pg->cachectl));
+	segpage(s, pg);
+	k = kmap(s->map[0]->pages[0]);
+	memmove((ulong*)VA(k), initcode, sizeof initcode);
+	kunmap(k);
+	ready(p);
+}
+
+uchar *
+pusharg(char *p)
+{
+	int n;
+
+	n = strlen(p)+1;
+	sp -= n;
+	memmove(sp, p, n);
+	return sp;
+}
+
+void
+bootargs(ulong base)
+{
+ 	int i, ac;
+	uchar *av[32];
+	uchar **lsp;
+
+	sp = (uchar*)base + BY2PG - Ustkheadroom;
+
+	ac = 0;
+	av[ac++] = pusharg("/386/9dos");
+	av[ac++] = pusharg("-D");
+
+	/* 4 byte word align stack */
+	sp = (uchar*)((ulong)sp & ~3);
+
+	/* build argc, argv on stack */
+	sp -= (ac+1)*sizeof(sp);
+	lsp = (uchar**)sp;
+	for(i = 0; i < ac; i++)
+		*lsp++ = av[i] + ((USTKTOP - BY2PG) - base);
+	*lsp = 0;
+	sp += (USTKTOP - BY2PG) - base - sizeof(ulong);
+}
+
+char*
+getconf(char *name)
+{
+	int i;
+
+	for(i = 0; i < nconf; i++)
+		if(cistrcmp(confname[i], name) == 0)
+			return confval[i];
+	return 0;
+}
+
+static void
+writeconf(void)
+{
+	char *p, *q;
+	int n;
+
+	p = getconfenv();
+
+	if(waserror()) {
+		free(p);
+		nexterror();
+	}
+
+	/* convert to name=value\n format */
+	for(q=p; *q; q++) {
+		q += strlen(q);
+		*q = '=';
+		q += strlen(q);
+		*q = '\n';
+	}
+	n = q - p + 1;
+	if(n >= BOOTARGSLEN)
+		error("kernel configuration too large");
+	memmove(BOOTARGS, p, n);
+	poperror();
+	free(p);
+}
+
+void
+confinit(void)
+{
+	char *p;
+	int i, userpcnt;
+	ulong kpages;
+
+	for(i = 0; i < nconf; i++)
+		print("%s=%s\n", confname[i], confval[i]);
+	/* 
+	 * all ram above xentop is free, but must be mappable
+	 * to virt addrs less than VIRT_START.
+	 */
+	kpages = PADDR(hypervisor_virt_start)>>PGSHIFT;
+	if(xenstart->nr_pages <= kpages)
+		kpages = xenstart->nr_pages;
+	else
+		print("Warning: Plan 9 / Xen limitation - "
+			  "using only %lud of %lud available RAM pages\n",
+			  kpages, xenstart->nr_pages);
+	xentop = PGROUND(PADDR(xentop));
+	conf.mem[0].npage = kpages - (xentop>>PGSHIFT);
+	conf.mem[0].base = xentop;
+
+	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;
+
+		/*
+		 * 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(kpages > (64*MB + conf.npage*sizeof(Page))/BY2PG){
+			kpages = (64*MB + conf.npage*sizeof(Page))/BY2PG;
+			conf.nimage = 2000;
+			kpages += (conf.nproc*KSTACK)/BY2PG;
+		}
+	} else {
+		if(userpcnt < 10) {
+			if(conf.npage*BY2PG < 16*MB)
+				userpcnt = 40;
+			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*1024*1024;
+	}
+
+	/*
+	 * 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
+	 * (probably ~300KB).
+	 */
+	kpages *= BY2PG;
+	kpages -= conf.upages*sizeof(Page)
+		+ conf.nproc*sizeof(Proc)
+		+ conf.nimage*sizeof(Image)
+		+ conf.nswap
+		+ conf.nswppo*sizeof(Page);
+	mainmem->maxsize = kpages;
+	if(!cpuserver){
+		/*
+		 * give terminals lots of image memory, too; the dynamic
+		 * allocation will balance the load properly, hopefully.
+		 * be careful with 32-bit overflow.
+		 */
+		imagmem->maxsize = kpages;
+	}
+}
+
+static char* mathmsg[] =
+{
+	nil,	/* handled below */
+	"denormalized operand",
+	"division by zero",
+	"numeric overflow",
+	"numeric underflow",
+	"precision loss",
+};
+
+static void
+mathnote(void)
+{
+	int i;
+	ulong status;
+	char *msg, note[ERRMAX];
+
+	status = up->fpsave.status;
+
+	/*
+	 * Some attention should probably be paid here to the
+	 * exception masks and error summary.
+	 */
+	msg = "unknown exception";
+	for(i = 1; i <= 5; i++){
+		if(!((1<<i) & status))
+			continue;
+		msg = mathmsg[i];
+		break;
+	}
+	if(status & 0x01){
+		if(status & 0x40){
+			if(status & 0x200)
+				msg = "stack overflow";
+			else
+				msg = "stack underflow";
+		}else
+			msg = "invalid operation";
+	}
+ 	snprint(note, sizeof note, "sys: fp: %s fppc=0x%lux status=0x%lux",
+ 		msg, up->fpsave.pc, status);
+	postnote(up, 1, note, NDebug);
+}
+
+/*
+ *  math coprocessor error
+ */
+static void
+matherror(Ureg *ur, void*)
+{
+	/*
+	 *  a write cycle to port 0xF0 clears the interrupt latch attached
+	 *  to the error# line from the 387
+	 */
+	if(!(m->cpuiddx & 0x01))
+		outb(0xF0, 0xFF);
+
+	/*
+	 *  save floating point state to check out error
+	 */
+	fpenv(&up->fpsave);
+	mathnote();
+
+	if(ur->pc & KZERO)
+		panic("fp: status %ux fppc=0x%lux pc=0x%lux",
+			up->fpsave.status, up->fpsave.pc, ur->pc);
+}
+
+/*
+ *  math coprocessor emulation fault
+ */
+static void
+mathemu(Ureg *ureg, void*)
+{
+	if(up->fpstate & FPillegal){
+		/* someone did floating point in a note handler */
+		postnote(up, 1, "sys: floating point in note handler", NDebug);
+		return;
+	}
+	switch(up->fpstate){
+	case FPinit:
+		fpinit();
+		up->fpstate = FPactive;
+		break;
+	case FPinactive:
+		/*
+		 * Before restoring the state, check for any pending
+		 * exceptions, there's no way to restore the state without
+		 * generating an unmasked exception.
+		 * More attention should probably be paid here to the
+		 * exception masks and error summary.
+		 */
+		if((up->fpsave.status & ~up->fpsave.control) & 0x07F){
+			mathnote();
+			break;
+		}
+		fprestore(&up->fpsave);
+		up->fpstate = FPactive;
+		break;
+	case FPactive:
+		panic("math emu pid %ld %s pc 0x%lux", 
+			up->pid, up->text, ureg->pc);
+		break;
+	}
+}
+
+/*
+ *  math coprocessor segment overrun
+ */
+static void
+mathover(Ureg*, void*)
+{
+	pexit("math overrun", 0);
+}
+
+void
+mathinit(void)
+{
+	trapenable(VectorCERR, matherror, 0, "matherror");
+	//if(X86FAMILY(m->cpuidax) == 3)
+	//	intrenable(IrqIRQ13, matherror, 0, BUSUNKNOWN, "matherror");
+	trapenable(VectorCNA, mathemu, 0, "mathemu");
+	trapenable(VectorCSO, mathover, 0, "mathover");
+}
+
+/*
+ *  set up floating point for a new process
+ */
+void
+procsetup(Proc*p)
+{
+	p->fpstate = FPinit;
+	fpoff();
+}
+
+void
+procfork(Proc *p)
+{
+	int s;
+
+	p->kentry = up->kentry;
+	p->pcycles = -p->kentry;
+
+	/* 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;
+	}
+
+	/* save floating point state */
+	s = splhi();
+	switch(up->fpstate & ~FPillegal){
+	case FPactive:
+		fpsave(&up->fpsave);
+		up->fpstate = FPinactive;
+	case FPinactive:
+		p->fpsave = up->fpsave;
+		p->fpstate = FPinactive;
+	}
+	splx(s);
+}
+
+void
+procrestore(Proc *p)
+{
+	uvlong t;
+
+	if(p->kp)
+		return;
+	cycles(&t);
+	p->pcycles -= t;
+}
+
+/*
+ *  Save the mach dependent part of the process state.
+ */
+void
+procsave(Proc *p)
+{
+	uvlong t;
+
+	cycles(&t);
+	p->pcycles += t;
+	if(p->fpstate == FPactive){
+		if(p->state == Moribund)
+			fpclear();
+		else{
+			/*
+			 * Fpsave() stores without handling pending
+			 * unmasked exeptions. Postnote() can't be called
+			 * here as sleep() already has up->rlock, so
+			 * the handling of pending exceptions is delayed
+			 * until the process runs again and generates an
+			 * emulation fault to activate the FPU.
+			 */
+			fpsave(&p->fpsave);
+		}
+		p->fpstate = FPinactive;
+	}
+
+	/*
+	 * 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(0);
+}
+
+static void
+shutdown(int ispanic)
+{
+	int ms, once;
+
+	lock(&active);
+	if(ispanic)
+		active.ispanic = ispanic;
+	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
+		active.ispanic = 0;
+	once = active.machs & (1<<m->machno);
+	active.machs &= ~(1<<m->machno);
+	active.exiting = 1;
+	unlock(&active);
+
+	if(once)
+		print("cpu%d: exiting\n", m->machno);
+	//spllo();
+	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
+		delay(TK2MS(2));
+		if(active.machs == 0 && consactive() == 0)
+			break;
+	}
+
+	if(getconf("*debug"))
+		delay(5*60*1000);
+
+	if(active.ispanic){
+		if(!cpuserver)
+			for(;;)
+				halt();
+		delay(10000);
+	}else
+		delay(1000);
+}
+
+void
+reboot(void *entry, void *code, ulong size)
+{
+	void (*f)(ulong, ulong, ulong);
+	//ulong *pdb;
+
+	writeconf();
+
+	shutdown(0);
+
+	/*
+	 * should be the only processor running now
+	 */
+
+	print("shutting down...\n");
+	delay(200);
+
+	splhi();
+
+	/* turn off buffered serial console */
+	serialoq = nil;
+
+	/* shutdown devices */
+	chandevshutdown();
+
+	/* reboot(0, ...) on Xen causes domU shutdown */
+	if(entry == 0)
+		HYPERVISOR_shutdown(0);
+
+	/*
+	 * 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(0);
+
+	/* setup reboot trampoline function */
+	f = (void*)REBOOTADDR;
+	memmove(f, rebootcode, sizeof(rebootcode));
+
+	print("rebooting...\n");
+
+	/* off we go - never to return */
+	(*f)(PADDR(entry), PADDR(code), size);
+}
+
+
+void
+exit(int ispanic)
+{
+	shutdown(ispanic);
+	arch->reset();
+}
+
+int
+cistrcmp(char *a, char *b)
+{
+	int ac, bc;
+
+	for(;;){
+		ac = *a++;
+		bc = *b++;
+	
+		if(ac >= 'A' && ac <= 'Z')
+			ac = 'a' + (ac - 'A');
+		if(bc >= 'A' && bc <= 'Z')
+			bc = 'a' + (bc - 'A');
+		ac -= bc;
+		if(ac)
+			return ac;
+		if(bc == 0)
+			break;
+	}
+	return 0;
+}
+
+int
+cistrncmp(char *a, char *b, int n)
+{
+	unsigned ac, bc;
+
+	while(n > 0){
+		ac = *a++;
+		bc = *b++;
+		n--;
+
+		if(ac >= 'A' && ac <= 'Z')
+			ac = 'a' + (ac - 'A');
+		if(bc >= 'A' && bc <= 'Z')
+			bc = 'a' + (bc - 'A');
+
+		ac -= bc;
+		if(ac)
+			return ac;
+		if(bc == 0)
+			break;
+	}
+
+	return 0;
+}
+