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

1 files changed, 162 insertions, 0 deletions

diff --git a/sys/src/9/xen/xenbin.c b/sys/src/9/xen/xenbin.c
new file mode 100644
index 000000000..1f6844e0e
--- /dev/null
+++ b/sys/src/9/xen/xenbin.c
@@ -0,0 +1,162 @@
+/*
+ * Transform a Plan 9 386 bootable image to make it compatible with
+ * the Xen binary image loader:
+ *
+ * - pad the beginning of the text with zeroes so that the image can be loaded at
+ *    guest 'physical' address 0
+ * - insert a Xen header
+ * - pad the end of the text so that data segment is page-aligned in the file
+ * - adjust the linenumber-pc table so Plan 9 debuggers won't be confused
+ */
+
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <mach.h>
+
+#define PAGE	4096
+#define PLAN9HDR	32
+#define XENHDR	32
+#define	KZERO	0x80000000
+#define FLAG_VALID	(1<<16)
+#define FLAG_PAE	(1<<14)
+
+void
+lput(long n)
+{
+	char buf[sizeof(long)];
+	int i;
+
+	for (i = sizeof(long)-1; i >= 0; i--) {
+		buf[i] = n;
+		n >>= 8;
+	}
+	write(1, buf, sizeof(long));
+}
+
+void
+rput(long n)
+{
+	char buf[sizeof(long)];
+	int i;
+
+	for (i = 0; i < sizeof(long); i++) {
+		buf[i] = n;
+		n >>= 8;
+	}
+	write(1, buf, sizeof(long));
+}
+
+void
+copy(long n)
+{
+	char buf[PAGE];
+	int m;
+
+	while (n > 0) {
+		m = sizeof buf;
+		if (m > n)
+			m = n;
+		read(0, buf, m);
+		write(1, buf, m);
+		n -= m;
+	}
+}
+
+void pad(int n)
+{
+	char buf[PAGE];
+	int m;
+
+	memset(buf, 0, sizeof buf);
+	while (n > 0) {
+		m = sizeof buf;
+		if (m > n)
+			m = n;
+		write(1, buf, m);
+		n -= m;
+	}
+}
+
+/*
+ * See /sys/src/cmd/8l/span.c:/^asmlc
+ */
+void adjustlnpc(int v)
+{
+	char buf[PAGE];
+	int n, s;
+
+	n = 0;
+	while (v) {
+		s = 127;
+		if (v < 127)
+			s = v;
+		buf[n++] = s+128;
+		if (n == sizeof buf) {
+			write(1, buf, n);
+			n = 0;
+		}
+		v -= s;
+	}
+	if (n > 0)
+		write(1, buf, n);
+}
+
+void
+main(int argc, char **argv)
+{
+	Fhdr fhdr;
+	long newtxtsz;
+	long newentry;
+	long newlnpcsz;
+	long prepad, postpad;
+	long flags;
+
+	flags = FLAG_VALID;
+	if (argc > 1 && strcmp(argv[1], "-p") == 0)
+		flags |= FLAG_PAE;
+
+	crackhdr(0, &fhdr);
+
+	newtxtsz = ((fhdr.txtsz+PLAN9HDR+PAGE-1)&~(PAGE-1)) - PLAN9HDR;
+	newentry = KZERO+PLAN9HDR;
+	prepad = fhdr.entry - newentry;
+	postpad = newtxtsz - fhdr.txtsz;
+	newtxtsz += prepad;
+	newlnpcsz = fhdr.lnpcsz;
+	if (newlnpcsz)
+		newlnpcsz += (prepad+126)/127;
+
+	/* plan 9 header */
+	lput(4*11*11+7);		/* magic */
+	lput(newtxtsz);			/* sizes */
+	lput(fhdr.datsz);
+	lput(fhdr.bsssz);
+	lput(fhdr.symsz);		/* nsyms */
+	lput(newentry);		/* va of entry */
+	lput(fhdr.sppcsz);		/* sp offsets */
+	lput(newlnpcsz);		/* line offsets */
+
+	/* xen header */
+	rput(0x336EC578);	/* magic */
+	rput(flags);		/* flags */
+	rput(-(0x336EC578+flags));	/* checksum */
+	rput(newentry);	/* header_addr */
+	rput(KZERO);	/* load_addr */
+	rput(KZERO+newtxtsz+fhdr.datsz);	/* load_end_addr */
+	rput(KZERO+newtxtsz+fhdr.datsz+fhdr.bsssz);	/* bss_end_addr */
+	rput(fhdr.entry);	/* entry_addr */
+
+	pad(prepad-XENHDR);
+
+	seek(0, fhdr.txtoff, 0);
+	copy(fhdr.txtsz);
+	pad(postpad);
+	copy(fhdr.datsz);
+	copy(fhdr.symsz);
+	if (newlnpcsz) {
+		adjustlnpc(prepad);
+		copy(fhdr.lnpcsz);
+	}
+	exits(0);
+}