| From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 181/206] s390/vmem: fix identity mapping | Date | Thu, 9 Jun 2016 14:16:30 -0700 |
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4.2.8-ckt12 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
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: Kamal Mostafa <kamal@canonical.com> --- arch/s390/mm/vmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index ef7d6c8..f354fd8 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -372,7 +372,7 @@ 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) -- 2.7.4
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