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-rw-r--r--arch/s390/include/asm/extmem.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/s390/include/asm/extmem.h b/arch/s390/include/asm/extmem.h
index 568fd81bb77b..e0a06060afdd 100644
--- a/arch/s390/include/asm/extmem.h
+++ b/arch/s390/include/asm/extmem.h
@@ -8,6 +8,13 @@
#define _ASM_S390X_DCSS_H
#ifndef __ASSEMBLY__
+/*
+ * DCSS segment is defined as a contiguous range of pages using DEFSEG command.
+ * The range start and end is a page number with a value less than or equal to
+ * 0x7ffffff (see CP Commands and Utilities Reference).
+ */
+#define MAX_DCSS_ADDR (512UL * SZ_1G)
+
/* possible values for segment type as returned by segment_info */
#define SEG_TYPE_SW 0
#define SEG_TYPE_EW 1