1 files changed, 117 insertions, 0 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index 33a8b6f7b626..adb5a3c4bf06 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -2242,6 +2242,123 @@ void __init memblock_free_all(void)
 	totalram_pages_add(pages);
 }
 
+/* Keep a table to reserve named memory */
+#define RESERVE_MEM_MAX_ENTRIES		8
+#define RESERVE_MEM_NAME_SIZE		16
+struct reserve_mem_table {
+	char			name[RESERVE_MEM_NAME_SIZE];
+	phys_addr_t		start;
+	phys_addr_t		size;
+};
+static struct reserve_mem_table reserved_mem_table[RESERVE_MEM_MAX_ENTRIES];
+static int reserved_mem_count;
+
+/* Add wildcard region with a lookup name */
+static void __init reserved_mem_add(phys_addr_t start, phys_addr_t size,
+				   const char *name)
+{
+	struct reserve_mem_table *map;
+
+	map = &reserved_mem_table[reserved_mem_count++];
+	map->start = start;
+	map->size = size;
+	strscpy(map->name, name);
+}
+
+/**
+ * reserve_mem_find_by_name - Find reserved memory region with a given name
+ * @name: The name that is attached to a reserved memory region
+ * @start: If found, holds the start address
+ * @size: If found, holds the size of the address.
+ *
+ * @start and @size are only updated if @name is found.
+ *
+ * Returns: 1 if found or 0 if not found.
+ */
+int reserve_mem_find_by_name(const char *name, phys_addr_t *start, phys_addr_t *size)
+{
+	struct reserve_mem_table *map;
+	int i;
+
+	for (i = 0; i < reserved_mem_count; i++) {
+		map = &reserved_mem_table[i];
+		if (!map->size)
+			continue;
+		if (strcmp(name, map->name) == 0) {
+			*start = map->start;
+			*size = map->size;
+			return 1;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(reserve_mem_find_by_name);
+
+/*
+ * Parse reserve_mem=nn:align:name
+ */
+static int __init reserve_mem(char *p)
+{
+	phys_addr_t start, size, align, tmp;
+	char *name;
+	char *oldp;
+	int len;
+
+	if (!p)
+		return -EINVAL;
+
+	/* Check if there's room for more reserved memory */
+	if (reserved_mem_count >= RESERVE_MEM_MAX_ENTRIES)
+		return -EBUSY;
+
+	oldp = p;
+	size = memparse(p, &p);
+	if (!size || p == oldp)
+		return -EINVAL;
+
+	if (*p != ':')
+		return -EINVAL;
+
+	align = memparse(p+1, &p);
+	if (*p != ':')
+		return -EINVAL;
+
+	/*
+	 * memblock_phys_alloc() doesn't like a zero size align,
+	 * but it is OK for this command to have it.
+	 */
+	if (align < SMP_CACHE_BYTES)
+		align = SMP_CACHE_BYTES;
+
+	name = p + 1;
+	len = strlen(name);
+
+	/* name needs to have length but not too big */
+	if (!len || len >= RESERVE_MEM_NAME_SIZE)
+		return -EINVAL;
+
+	/* Make sure that name has text */
+	for (p = name; *p; p++) {
+		if (!isspace(*p))
+			break;
+	}
+	if (!*p)
+		return -EINVAL;
+
+	/* Make sure the name is not already used */
+	if (reserve_mem_find_by_name(name, &start, &tmp))
+		return -EBUSY;
+
+	start = memblock_phys_alloc(size, align);
+	if (!start)
+		return -ENOMEM;
+
+	reserved_mem_add(start, size, name);
+
+	return 1;
+}
+__setup("reserve_mem=", reserve_mem);
+
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
 static const char * const flagname[] = {
 	[ilog2(MEMBLOCK_HOTPLUG)] = "HOTPLUG",