s390/mm: fix gmap tlb flush issues

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commit f045402984 upstream.

__tlb_flush_asce() should never be used if multiple asce belong to a mm.

As this function changes mm logic determining if local or global tlb
flushes will be neded, we might end up flushing only the gmap asce on all
CPUs and a follow up mm asce flushes will only flush on the local CPU,
although that asce ran on multiple CPUs.

The missing tlb flushes will provoke strange faults in user space and even
low address protections in user space, crashing the kernel.

Fixes: 1b948d6cae ("s390/mm,tlb: optimize TLB flushing for zEC12")
Reported-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

...

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David Hildenbrand 2016-07-07 10:44:10 +02:00 • committed by Ben Hutchings

parent de041bc621

commit 60582f6e9a

2 changed files with 4 additions and 3 deletions

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3

arch/s390/include/asm/tlbflush.h

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4

arch/s390/mm/pgtable.c

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