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    Subject[PATCH 3.16 065/305] s390/vmem: fix identity mapping
    3.16.37-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Heiko Carstens <heiko.carstens@de.ibm.com>

    commit c34a69059d7876e0793eb410deedfb08ccb22b02 upstream.

    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>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    arch/s390/mm/vmem.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/arch/s390/mm/vmem.c
    +++ b/arch/s390/mm/vmem.c
    @@ -380,7 +380,7 @@ 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)
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