Commit c34a6905 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky

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 50be6345 ("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: 50be6345 ("s390/mm: Convert bootmem to memblock")
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent ca21872e
...@@ -370,7 +370,7 @@ void __init vmem_map_init(void) ...@@ -370,7 +370,7 @@ void __init vmem_map_init(void)
ro_end = (unsigned long)&_eshared & PAGE_MASK; ro_end = (unsigned long)&_eshared & PAGE_MASK;
for_each_memblock(memory, reg) { for_each_memblock(memory, reg) {
start = reg->base; start = reg->base;
end = reg->base + reg->size - 1; end = reg->base + reg->size;
if (start >= ro_end || end <= ro_start) if (start >= ro_end || end <= ro_start)
vmem_add_mem(start, end - start, 0); vmem_add_mem(start, end - start, 0);
else if (start >= ro_start && end <= ro_end) else if (start >= ro_start && end <= ro_end)
......
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