code: plan9front

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arm64/qemu: detect VM configuration

Now, *maxmem and *ncpu are not required to be provided.
They will be detected automatically from the QEMU device
tree. Further, >4GB memory configurations are also supported.
The maximum number of CPUs is 16 for now, and the maximum
supported memory is 16GB

--- /dev/null

+++ b/sys/src/9/arm64/bootargs.c

@@ -1,0 +1,249 @@

+#include	"u.h"

+#include	"../port/lib.h"

+#include	"mem.h"

+#include	"dat.h"

+#include	"fns.h"

+

+#define	MAXCONF 64

+static char *confname[MAXCONF];

+static char *confval[MAXCONF];

+static int nconf;

+static char maxmem[256];

+static int cpus;

+static char ncpu[256];

+

+static int

+findconf(char *k)

+{

+	int i;

+

+	for(i = 0; i < nconf; i++)

+		if(cistrcmp(confname[i], k) == 0)

+			return i;

+	return -1;

+}

+

+static void

+addconf(char *k, char *v)

+{

+	int i;

+

+	i = findconf(k);

+	if(i < 0){

+		if(nconf >= MAXCONF)

+			return;

+		i = nconf++;

+		confname[i] = k;

+	}

+	confval[i] = v;

+}

+

+static void

+plan9iniinit(char *s, int cmdline)

+{

+	char *toks[MAXCONF];

+	int i, c, n;

+	char *v;

+

+	if((c = *s) < ' ' || c >= 0x80)

+		return;

+	if(cmdline)

+		n = tokenize(s, toks, MAXCONF);

+	else

+		n = getfields(s, toks, MAXCONF, 1, "\n");

+	for(i = 0; i < n; i++){

+		if(toks[i][0] == '#')

+			continue;

+		v = strchr(toks[i], '=');

+		if(v == nil)

+			continue;

+		*v++ = '\0';

+		addconf(toks[i], v);

+	}

+}

+

+typedef struct Devtree Devtree;

+struct Devtree

+{

+	uchar	*base;

+	uchar	*end;

+	char	*stab;

+	char	path[1024];

+};

+

+enum {

+	DtHeader	= 0xd00dfeed,

+	DtBeginNode	= 1,

+	DtEndNode	= 2,

+	DtProp		= 3,

+	DtEnd		= 9,

+};

+

+static u32int

+beget4(uchar *p)

+{

+	return (u32int)p[0]<<24 | (u32int)p[1]<<16 | (u32int)p[2]<<8 | (u32int)p[3];

+}

+

+static void

+devtreeprop(char *path, char *key, void *val, int len)

+{

+	uvlong addr;

+	uchar *p = val;

+

+	if((strncmp(path, "/memory", 7) == 0 || strncmp(path, "/memory@0", 9) == 0)

+	&& strcmp(key, "reg") == 0){

+		if(findconf("*maxmem") < 0 && len == 16){

+			p += 4;	/* ignore */

+			addr = (uvlong)beget4(p+4)<<32 | beget4(p);

+			addr += beget4(p+8);

+			snprint(maxmem, sizeof(maxmem), "%#llux", addr);

+			addconf("*maxmem", maxmem);

+		}

+		return;

+	}

+	if(strncmp(path, "/cpus/cpu", 9) == 0 && strcmp(key, "reg") == 0){

+		cpus++;

+		return;

+	}

+	if(strncmp(path, "/chosen", 7) == 0 && strcmp(key, "bootargs") == 0){

+		if(len > BOOTARGSLEN)

+			len = BOOTARGSLEN;

+		memmove(BOOTARGS, val, len);

+		plan9iniinit(BOOTARGS, 1);

+		return;

+	}

+}

+

+static uchar*

+devtreenode(Devtree *t, uchar *p, char *cp)

+{

+	uchar *e = (uchar*)t->stab;

+	char *s;

+	int n;

+

+	if(p+4 > e || beget4(p) != DtBeginNode)

+		return nil;

+	p += 4;

+	if((s = memchr((char*)p, 0, e - p)) == nil)

+		return nil;

+	n = s - (char*)p;

+	cp += n;

+	if(cp >= &t->path[sizeof(t->path)])

+		return nil;

+	memmove(cp - n, (char*)p, n);

+	*cp = 0;

+	p += (n + 4) & ~3;

+	while(p+12 <= e && beget4(p) == DtProp){

+		n = beget4(p+4);

+		if(p + 12 + n > e)

+			return nil;

+		s = t->stab + beget4(p+8);

+		if(s < t->stab || s >= (char*)t->end

+		|| memchr(s, 0, (char*)t->end - s) == nil)

+			return nil;

+		devtreeprop(t->path, s, p+12, n);

+		p += 12 + ((n + 3) & ~3);

+	}

+	while(p+4 <= e && beget4(p) == DtBeginNode){

+		*cp = '/';

+		p = devtreenode(t, p, cp+1);

+		if(p == nil)

+			return nil;

+	}

+	if(p+4 > e || beget4(p) != DtEndNode)

+		return nil;

+	return p+4;

+}

+

+static int

+parsedevtree(uchar *base, uintptr len)

+{

+	Devtree t[1];

+	u32int total;

+

+	if(len < 28 || beget4(base) != DtHeader)

+		return -1;

+	total = beget4(base+4);

+	if(total < 28 || total > len)

+		return -1;

+	t->base = base;

+	t->end = t->base + total;

+	t->stab = (char*)base + beget4(base+12);

+	if(t->stab >= (char*)t->end)

+		return -1;

+	devtreenode(t, base + beget4(base+8), t->path);

+	return  0;

+}

+

+void

+bootargsinit(void)

+{

+	void *va = KADDR(DTBADDR);

+	uintptr len = cankaddr(DTBADDR);

+

+	plan9iniinit(BOOTARGS, 0);

+	if(parsedevtree(va, len) == 0){

+		/* user can provide fewer ncpu */

+		if(findconf("*ncpu") < 0){

+			snprint(ncpu, sizeof(ncpu), "%d", cpus);

+			addconf("*ncpu", ncpu);

+		}

+	}

+}

+

+char*

+getconf(char *name)

+{

+	int i;

+

+	if((i = findconf(name)) < 0)

+		return nil;

+	return confval[i];

+}

+

+void

+setconfenv(void)

+{

+	int i;

+

+	if(nconf < 0){

+		/* use defaults when there was no configuration */

+		ksetenv("console", "0", 1);

+		return;

+	}

+

+	for(i = 0; i < nconf; i++){

+		if(confname[i][0] != '*')

+			ksetenv(confname[i], confval[i], 0);

+		ksetenv(confname[i], confval[i], 1);

+	}

+}

+

+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);

+	memset(BOOTARGS+n, 0, BOOTARGSLEN-n);

+	poperror();

+	free(p);

+}

--- a/sys/src/9/arm64/fns.h

+++ b/sys/src/9/arm64/fns.h

@@ -168,3 +168,6 @@

 extern int pcicfgrw32(int tbdf, int rno, int data, int read);

 extern void pciintrenable(int tbdf, void (*f)(Ureg*, void*), void *a);

 extern void pciintrdisable(int tbdf, void (*f)(Ureg*, void*), void *a);

+

+/* bootargs */

+extern void bootargsinit(void);

--- a/sys/src/9/arm64/main.c

+++ b/sys/src/9/arm64/main.c

@@ -14,120 +14,6 @@

 Conf conf;

-#define	MAXCONF 64

-static char *confname[MAXCONF];

-static char *confval[MAXCONF];

-static int nconf = -1;

-

-void

-bootargsinit(void)

-{

-	int i, j, n;

-	char *cp, *line[MAXCONF], *p, *q;

-

-	/*

-	 *  parse configuration args from dos file plan9.ini

-	 */

-	cp = BOOTARGS;

-	cp[BOOTARGSLEN-1] = 0;

-

-	/*

-	 * Strip out '\r', change '\t' -> ' '.

-	 */

-	p = cp;

-	for(q = cp; *q; q++){

-		if(*q == -1)

-			break;

-		if(*q == '\r')

-			continue;

-		if(*q == '\t')

-			*q = ' ';

-		*p++ = *q;

-	}

-	*p = 0;

-

-	n = getfields(cp, line, MAXCONF, 1, "\n");

-	if(n <= 0){

-		/* empty plan9.ini, no configuration passed */

-		return;

-	}

-

-	nconf = 0;

-	for(i = 0; i < n; i++){

-		if(*line[i] == '#')

-			continue;

-		cp = strchr(line[i], '=');

-		if(cp == nil)

-			continue;

-		*cp++ = '\0';

-		for(j = 0; j < nconf; j++){

-			if(cistrcmp(confname[j], line[i]) == 0)

-				break;

-		}

-		confname[j] = line[i];

-		confval[j] = cp;

-		if(j == nconf)

-			nconf++;

-	}

-}

-

-char*

-getconf(char *name)

-{

-	int i;

-

-	for(i = 0; i < nconf; i++)

-		if(cistrcmp(confname[i], name) == 0)

-			return confval[i];

-	return nil;

-}

-

-void

-setconfenv(void)

-{

-	int i;

-

-	if(nconf < 0){

-		/* use defaults when there was no configuration */

-		ksetenv("console", "0", 1);

-		return;

-	}

-

-	for(i = 0; i < nconf; i++){

-		if(confname[i][0] != '*')

-			ksetenv(confname[i], confval[i], 0);

-		ksetenv(confname[i], confval[i], 1);

-	}

-}

-

-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);

-	memset(BOOTARGS+n, 0, BOOTARGSLEN-n);

-	poperror();

-	free(p);

-}

-

 int

 isaconfig(char *, int, ISAConf *)

 {

--- a/sys/src/9/arm64/mem.c

+++ b/sys/src/9/arm64/mem.c

@@ -67,13 +67,16 @@

 meminit(void)

 {

 	char *p;

+	uintptr l = GiB + 128 * MiB;

-	conf.mem[0].base = PGROUND((uintptr)end - KZERO);

-	conf.mem[0].limit = GiB + 128 * MiB;

 	if(p = getconf("*maxmem"))

-		conf.mem[0].limit = strtoull(p, 0, 0);

+		l = strtoull(p, 0, 0);

+	conf.mem[0].base = PGROUND((uintptr)end - KZERO);

+	conf.mem[0].limit = l;

-	kmapram(conf.mem[0].base, conf.mem[0].limit);

+	if(l > KLIMIT)

+		l = KLIMIT;

+	kmapram(conf.mem[0].base, l);

 	conf.mem[0].npage = (conf.mem[0].limit - conf.mem[0].base)/BY2PG;

 }

--- a/sys/src/9/arm64/mem.h

+++ b/sys/src/9/arm64/mem.h

@@ -18,7 +18,7 @@

 #define	PGROUND(s)	ROUND(s, BY2PG)

 /* effective virtual address space */

-#define EVASHIFT	34

+#define EVASHIFT	36

 #define EVAMASK		((1ULL<<EVASHIFT)-1)

 #define PTSHIFT		(PGSHIFT-3)

@@ -32,7 +32,7 @@

 #define L1TABLE(v, l)	(L1TABLES - ((PTLX(v, 2) % L1TABLES) >> (((l)-1)*PTSHIFT)) + (l)-1)

 #define L1TOPSIZE	(1ULL << (EVASHIFT - PTLEVELS*PTSHIFT))

-#define	MAXMACH		24			/* max # cpus system can run */

+#define	MAXMACH		16			/* max # cpus system can run */

 #define	MACHSIZE	(8*KiB)

 #define KSTACK		(8*KiB)

@@ -39,6 +39,8 @@

 #define STACKALIGN(sp)	((sp) & ~7)		/* bug: assure with alloc */

 #define TRAPFRAMESIZE	(38*8)

+#define DTBADDR		0x40000000

+

 #define VDRAM		(0xFFFFFFFFC0000000ULL)	/* 0x40000000 - 0x80000000 */

 #define	KTZERO		(VDRAM + 0x100000)	/* 0x40100000 - kernel text start */

@@ -53,6 +55,8 @@

 #define KMAPEND		(0xFFFFFFFF00000000ULL)	/* 0x140000000 */

 #define KMAP		(0xFFFFFFFE00000000ULL)	/*  0x40000000 */

+

+#define KLIMIT		(VDRAM - KZERO + KMAPEND - KMAP)	/* 0x140000000 */

 #define KSEG0		(0xFFFFFFFE00000000ULL)

--- a/sys/src/9/arm64/mkfile

+++ b/sys/src/9/arm64/mkfile

@@ -51,6 +51,7 @@

 	sysreg.$O\

 	random.$O\

 	trap.$O\

+	bootargs.$O\

 	$CONF.root.$O\

 	$CONF.rootc.$O\

 	$DEVS\