s390/vmem: fix identity mapping

The identity mapping is suboptimal for the last 2GB frame. The mapping
will be established with a mix of 4KB and 1MB mappings instead of a
single 2GB mapping.

This happens because of a off-by-one bug introduced with
commit 50be63450728 ("s390/mm: Convert bootmem to memblock").

Currently the identity mapping looks like this:

0x0000000080000000-0x0000000180000000        4G PUD RW
0x0000000180000000-0x00000001fff00000     2047M PMD RW
0x00000001fff00000-0x0000000200000000        1M PTE RW

With the bug fixed it looks like this:

0x0000000080000000-0x0000000200000000        6G PUD RW

Fixes: 50be63450728 ("s390/mm: Convert bootmem to memblock")
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index d27fccbad7c1..f7ad6cd38e3e 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -370,7 +370,7 @@ void __init vmem_map_init(void)
         ro_end = (unsigned long)&_eshared & PAGE_MASK;
         for_each_memblock(memory, reg) {
                 start = reg->base;
-                end = reg->base + reg->size - 1;
+                end = reg->base + reg->size;
                 if (start >= ro_end || end <= ro_start)
                         vmem_add_mem(start, end - start, 0);
                 else if (start >= ro_start && end <= ro_end)