From 7e2e5b7a6f17c0a705eca774d82335408308f130 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@gmx.de>
Date: Thu, 31 Oct 2013 15:50:25 +0100
Subject: [PATCH] kernel: add support for multiboot memory map

---
 sys/src/9/pc/main.c | 64 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 49 insertions(+), 15 deletions(-)

diff --git a/sys/src/9/pc/main.c b/sys/src/9/pc/main.c
index c85c4f23a..3e5c3479c 100644
--- a/sys/src/9/pc/main.c
+++ b/sys/src/9/pc/main.c
@@ -32,27 +32,61 @@ int nconf;
 uchar *sp;	/* user stack of init proc */
 int delaylink;
 
+static void
+multibootargs(void)
+{
+	char *cp, *ep;
+	ulong *m, l;
+
+	extern ulong *multiboot;
+
+	if(multiboot == nil)
+		return;
+
+	/* command line */
+	if((multiboot[0] & (1<<2)) != 0)
+		strncpy(BOOTLINE, KADDR(multiboot[4]), BOOTLINELEN-1);
+
+	cp = BOOTARGS;
+	ep = cp + BOOTARGSLEN-1;
+
+	/* memory map */
+	if((multiboot[0] & (1<<6)) != 0 && (l = multiboot[11]) >= 24){
+		cp = seprint(cp, ep, "*e820=");
+		m = KADDR(multiboot[12]);
+		while(m[0] >= 20 && m[0] <= l-4){
+			uvlong base, size;
+			m++;
+			base = ((uvlong)m[0] | (uvlong)m[1]<<32);
+			size = ((uvlong)m[2] | (uvlong)m[3]<<32);
+			cp = seprint(cp, ep, "%.1x %.16llux %.16llux ",
+				m[4] & 0xF, base, base+size);
+			l -= m[-1]+4;
+			m = (ulong*)((ulong)m + m[-1]);
+		}
+		cp[-1] = '\n';
+	}
+
+	/* plan9.ini passed as the first module */
+	if((multiboot[0] & (1<<3)) != 0 && multiboot[5] > 0){
+		m = KADDR(multiboot[6]);
+		l = m[1] - m[0];
+		m = KADDR(m[0]);
+		if(cp+l > ep)
+			l = ep - cp;
+		memmove(cp, m, l);
+		cp += l;
+	}
+	*cp = 0;
+}
+
 static void
 options(void)
 {
 	long i, n;
 	char *cp, *line[MAXCONF], *p, *q;
-	ulong *m, l;
-	extern ulong *multiboot;
 
-	if(multiboot != nil){
-		cp = BOOTARGS;
-		*cp = 0;
-		if((*multiboot & 8) != 0 && multiboot[5] > 0){
-			m = KADDR(multiboot[6]);
-			l = m[1] - m[0];
-			m = KADDR(m[0]);
-			if(l >= BOOTARGSLEN)
-				l = BOOTARGSLEN - 1;
-			memmove(cp, m, l);
-			cp[l] = 0;
-		}
-	}
+	multibootargs();
 
 	/*
 	 *  parse configuration args from dos file plan9.ini