1 files changed, 94 insertions, 0 deletions
diff --git a/arch/s390/include/asm/mem_detect.h b/arch/s390/include/asm/mem_detect.h
new file mode 100644
index 000000000..a7c922a69
--- /dev/null
+++ b/arch/s390/include/asm/mem_detect.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_MEM_DETECT_H
+#define _ASM_S390_MEM_DETECT_H
+
+#include <linux/types.h>
+
+enum mem_info_source {
+	MEM_DETECT_NONE = 0,
+	MEM_DETECT_SCLP_STOR_INFO,
+	MEM_DETECT_DIAG260,
+	MEM_DETECT_SCLP_READ_INFO,
+	MEM_DETECT_BIN_SEARCH
+};
+
+struct mem_detect_block {
+	u64 start;
+	u64 end;
+};
+
+/*
+ * Storage element id is defined as 1 byte (up to 256 storage elements).
+ * In practise only storage element id 0 and 1 are used).
+ * According to architecture one storage element could have as much as
+ * 1020 subincrements. 255 mem_detect_blocks are embedded in mem_detect_info.
+ * If more mem_detect_blocks are required, a block of memory from already
+ * known mem_detect_block is taken (entries_extended points to it).
+ */
+#define MEM_INLINED_ENTRIES 255 /* (PAGE_SIZE - 16) / 16 */
+
+struct mem_detect_info {
+	u32 count;
+	u8 info_source;
+	struct mem_detect_block entries[MEM_INLINED_ENTRIES];
+	struct mem_detect_block *entries_extended;
+};
+extern struct mem_detect_info mem_detect;
+
+void add_mem_detect_block(u64 start, u64 end);
+
+static inline int __get_mem_detect_block(u32 n, unsigned long *start,
+					 unsigned long *end)
+{
+	if (n >= mem_detect.count) {
+		*start = 0;
+		*end = 0;
+		return -1;
+	}
+
+	if (n < MEM_INLINED_ENTRIES) {
+		*start = (unsigned long)mem_detect.entries[n].start;
+		*end = (unsigned long)mem_detect.entries[n].end;
+	} else {
+		*start = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].start;
+		*end = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].end;
+	}
+	return 0;
+}
+
+/**
+ * for_each_mem_detect_block - early online memory range iterator
+ * @i: an integer used as loop variable
+ * @p_start: ptr to unsigned long for start address of the range
+ * @p_end: ptr to unsigned long for end address of the range
+ *
+ * Walks over detected online memory ranges.
+ */
+#define for_each_mem_detect_block(i, p_start, p_end)			\
+	for (i = 0, __get_mem_detect_block(i, p_start, p_end);		\
+	     i < mem_detect.count;					\
+	     i++, __get_mem_detect_block(i, p_start, p_end))
+
+static inline void get_mem_detect_reserved(unsigned long *start,
+					   unsigned long *size)
+{
+	*start = (unsigned long)mem_detect.entries_extended;
+	if (mem_detect.count > MEM_INLINED_ENTRIES)
+		*size = (mem_detect.count - MEM_INLINED_ENTRIES) * sizeof(struct mem_detect_block);
+	else
+		*size = 0;
+}
+
+static inline unsigned long get_mem_detect_end(void)
+{
+	unsigned long start;
+	unsigned long end;
+
+	if (mem_detect.count) {
+		__get_mem_detect_block(mem_detect.count - 1, &start, &end);
+		return end;
+	}
+	return 0;
+}
+
+#endif