1 files changed, 169 insertions, 0 deletions
diff --git a/kexec/mem_regions.c b/kexec/mem_regions.c
new file mode 100644
index 0000000..ad7d3f1
--- /dev/null
+++ b/kexec/mem_regions.c
@@ -0,0 +1,169 @@
+#include <stdlib.h>
+
+#include "kexec.h"
+#include "mem_regions.h"
+
+static int mem_range_cmp(const void *a1, const void *a2)
+{
+	const struct memory_range *r1 = a1;
+	const struct memory_range *r2 = a2;
+
+	if (r1->start > r2->start)
+		return 1;
+	if (r1->start < r2->start)
+		return -1;
+
+	return 0;
+}
+
+/**
+ * mem_regions_sort() - sort ranges into ascending address order
+ * @ranges: ranges to sort
+ *
+ * Sort the memory regions into ascending address order.
+ */
+void mem_regions_sort(struct memory_ranges *ranges)
+{
+	qsort(ranges->ranges, ranges->size, sizeof(*ranges->ranges),
+	      mem_range_cmp);
+}
+
+/**
+ * mem_regions_add() - add a memory region to a set of ranges
+ * @ranges: ranges to add the memory region to
+ * @base: base address of memory region
+ * @length: length of memory region in bytes
+ * @type: type of memory region
+ *
+ * Add the memory region to the set of ranges, and return %0 if successful,
+ * or %-1 if we ran out of space.
+ */
+int mem_regions_add(struct memory_ranges *ranges, unsigned long long base,
+                    unsigned long long length, int type)
+{
+	struct memory_range *range;
+
+	if (ranges->size >= ranges->max_size)
+		return -1;
+
+	range = ranges->ranges + ranges->size++;
+	range->start = base;
+	range->end = base + length - 1;
+	range->type = type;
+
+	return 0;
+}
+
+static void mem_regions_remove(struct memory_ranges *ranges, int index)
+{
+	int tail_entries;
+
+	/* we are assured to have at least one entry */
+	ranges->size -= 1;
+
+	/* if we have following entries, shuffle them down one place */
+	tail_entries = ranges->size - index;
+	if (tail_entries)
+		memmove(ranges->ranges + index, ranges->ranges + index + 1,
+			tail_entries * sizeof(*ranges->ranges));
+
+	/* zero the new tail entry */
+	memset(ranges->ranges + ranges->size, 0, sizeof(*ranges->ranges));
+}
+
+/**
+ * mem_regions_exclude() - excludes a memory region from a set of memory ranges
+ * @ranges: memory ranges to exclude the region from
+ * @range: memory range to exclude
+ *
+ * Exclude a memory region from a set of memory ranges.  We assume that
+ * the region to be excluded is either wholely located within one of the
+ * memory ranges, or not at all.
+ */
+int mem_regions_exclude(struct memory_ranges *ranges,
+			const struct memory_range *range)
+{
+	int i, ret;
+
+	for (i = 0; i < ranges->size; i++) {
+		struct memory_range *r = ranges->ranges + i;
+
+		/*
+		 * We assume that crash area is fully contained in
+		 * some larger memory area.
+		 */
+		if (r->start <= range->start && r->end >= range->end) {
+			if (r->start == range->start) {
+				if (r->end == range->end)
+					/* Remove this entry */
+					mem_regions_remove(ranges, i);
+				else
+					/* Shrink the start of this memory range */
+					r->start = range->end + 1;
+			} else if (r->end == range->end) {
+				/* Shrink the end of this memory range */
+				r->end = range->start - 1;
+			} else {
+				/*
+				 * Split this area into 2 smaller ones and
+				 * remove excluded range from between. First
+				 * create new entry for the remaining area.
+				 */
+				ret = mem_regions_add(ranges, range->end + 1,
+						      r->end - range->end, 0);
+				if (ret < 0)
+					return ret;
+
+				/*
+				 * Update this area to end before excluded
+				 * range.
+				 */
+				r->end = range->start - 1;
+				break;
+			}
+		}
+	}
+	return 0;
+}
+
+#define KEXEC_MEMORY_RANGES 16
+
+int mem_regions_alloc_and_add(struct memory_ranges *ranges,
+			      unsigned long long base,
+			      unsigned long long length, int type)
+{
+	void *new_ranges;
+
+	if (ranges->size >= ranges->max_size) {
+		new_ranges = realloc(ranges->ranges,
+				sizeof(struct memory_range) *
+				(ranges->max_size + KEXEC_MEMORY_RANGES));
+		if (!new_ranges)
+			return -1;
+
+		ranges->ranges = new_ranges;
+		ranges->max_size += KEXEC_MEMORY_RANGES;
+	}
+
+	return mem_regions_add(ranges, base, length, type);
+}
+
+int mem_regions_alloc_and_exclude(struct memory_ranges *ranges,
+				  const struct memory_range *range)
+{
+	void *new_ranges;
+
+	/* for safety, we should have at least one free entry in ranges */
+	if (ranges->size >= ranges->max_size) {
+		new_ranges = realloc(ranges->ranges,
+				sizeof(struct memory_range) *
+				(ranges->max_size + KEXEC_MEMORY_RANGES));
+		if (!new_ranges)
+			return -1;
+
+		ranges->ranges = new_ranges;
+		ranges->max_size += KEXEC_MEMORY_RANGES;
+	}
+
+	return mem_regions_exclude(ranges, range);
+}