From 060fe1405f9717a6d83692504b0f704208d66dd8 Mon Sep 17 00:00:00 2001
From: "kfraser@localhost.localdomain" <kfraser@localhost.localdomain>
Date: Fri, 19 Jan 2007 14:24:28 +0000
Subject: [PATCH] [XEN] Convert between long-based and byte-based bitmap
 arrays. Use this for conversion of the domctl_cpumap type on big-endian
 systems. Original patch from Jimi Xenidis <jimix@watson.ibm.com>
 Signed-off-by: Keir Fraser <keir@xensource.com>

---
 xen/common/bitmap.c      | 51 ++++++++++++++++++++++++++++++++++++++++
 xen/common/domctl.c      | 19 ++++++++-------
 xen/include/xen/bitmap.h |  3 +++
 3 files changed, 65 insertions(+), 8 deletions(-)

diff --git a/xen/common/bitmap.c b/xen/common/bitmap.c
index 9bdc3157d1..76f55d29e8 100644
--- a/xen/common/bitmap.c
+++ b/xen/common/bitmap.c
@@ -10,6 +10,7 @@
 #include <xen/errno.h>
 #include <xen/bitmap.h>
 #include <xen/bitops.h>
+#include <asm/byteorder.h>
 
 /*
  * bitmaps provide an array of bits, implemented using an an
@@ -467,3 +468,53 @@ int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
 	return 0;
 }
 EXPORT_SYMBOL(bitmap_allocate_region);
+
+#ifdef __BIG_ENDIAN
+
+void bitmap_long_to_byte(uint8_t *bp, const unsigned long *lp, int nbits)
+{
+	unsigned long l;
+	int i, j, b;
+
+	for (i = 0, b = 0; nbits > 0; i++, b += sizeof(l)) {
+		l = lp[i];
+		for (j = 0; (j < sizeof(l)) && (nbits > 0); j++) {
+			bp[b+j] = l;
+			l >>= 8;
+			nbits -= 8;
+		}
+	}
+}
+
+void bitmap_byte_to_long(unsigned long *lp, const uint8_t *bp, int nbits)
+{
+	unsigned long l;
+	int i, j, b;
+
+	for (i = 0, b = 0; nbits > 0; i++, b += sizeof(l)) {
+		l = 0;
+		for (j = 0; (j < sizeof(l)) && (nbits > 0); j++) {
+			l <<= 8;
+			l |= bp[b+j];
+			nbits -= 8;
+		}
+		lp[i] = l;
+	}
+}
+
+#elif defined(__LITTLE_ENDIAN)
+
+void bitmap_long_to_byte(uint8_t *bp, const unsigned long *lp, int nbits)
+{
+	memcpy(bp, lp, (nbits+7)/8);
+}
+
+void bitmap_byte_to_long(unsigned long *lp, const uint8_t *bp, int nbits)
+{
+	/* We may need to pad the final longword with zeroes. */
+	if (nbits & (BITS_PER_LONG-1))
+		lp[BITS_TO_LONGS(nbits)-1] = 0;
+	memcpy(lp, bp, (nbits+7)/8);
+}
+
+#endif
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 4494c84494..230d204912 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -18,6 +18,7 @@
 #include <xen/console.h>
 #include <xen/iocap.h>
 #include <xen/guest_access.h>
+#include <xen/bitmap.h>
 #ifdef CONFIG_COMPAT
 #include <xen/compat.h>
 #endif
@@ -40,16 +41,17 @@ void cpumask_to_xenctl_cpumap(
 {
     unsigned int guest_bytes, copy_bytes, i;
     uint8_t zero = 0;
+    uint8_t bytemap[(NR_CPUS + 7) / 8];
 
     if ( guest_handle_is_null(xenctl_cpumap->bitmap) )
         return;
 
     guest_bytes = (xenctl_cpumap->nr_cpus + 7) / 8;
-    copy_bytes  = min_t(unsigned int, guest_bytes, (NR_CPUS + 7) / 8);
+    copy_bytes  = min_t(unsigned int, guest_bytes, sizeof(bytemap));
 
-    copy_to_guest(xenctl_cpumap->bitmap,
-                  (uint8_t *)cpus_addr(*cpumask),
-                  copy_bytes);
+    bitmap_long_to_byte(bytemap, cpus_addr(*cpumask), NR_CPUS);
+
+    copy_to_guest(xenctl_cpumap->bitmap, &bytemap[0], copy_bytes);
 
     for ( i = copy_bytes; i < guest_bytes; i++ )
         copy_to_guest_offset(xenctl_cpumap->bitmap, i, &zero, 1);
@@ -59,18 +61,19 @@ void xenctl_cpumap_to_cpumask(
     cpumask_t *cpumask, struct xenctl_cpumap *xenctl_cpumap)
 {
     unsigned int guest_bytes, copy_bytes;
+    uint8_t bytemap[(NR_CPUS + 7) / 8];
 
     guest_bytes = (xenctl_cpumap->nr_cpus + 7) / 8;
-    copy_bytes  = min_t(unsigned int, guest_bytes, (NR_CPUS + 7) / 8);
+    copy_bytes  = min_t(unsigned int, guest_bytes, sizeof(bytemap));
 
     cpus_clear(*cpumask);
 
     if ( guest_handle_is_null(xenctl_cpumap->bitmap) )
         return;
 
-    copy_from_guest((uint8_t *)cpus_addr(*cpumask),
-                    xenctl_cpumap->bitmap,
-                    copy_bytes);
+    copy_from_guest(&bytemap[0], xenctl_cpumap->bitmap, copy_bytes);
+
+    bitmap_byte_to_long(cpus_addr(*cpumask), bytemap, NR_CPUS);
 }
 
 #endif /* COMPAT */
diff --git a/xen/include/xen/bitmap.h b/xen/include/xen/bitmap.h
index 91622645c5..a8cd593d23 100644
--- a/xen/include/xen/bitmap.h
+++ b/xen/include/xen/bitmap.h
@@ -251,6 +251,9 @@ static inline void bitmap_shift_left(unsigned long *dst,
 		__bitmap_shift_left(dst, src, n, nbits);
 }
 
+void bitmap_long_to_byte(uint8_t *bp, const unsigned long *lp, int nbits);
+void bitmap_byte_to_long(unsigned long *lp, const uint8_t *bp, int nbits);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __XEN_BITMAP_H */
-- 
2.30.2