s390: avoid cache aliasing under z/VM and KVM
authorMartin Schwidefsky <schwidefsky@de.ibm.com>
Tue, 10 Nov 2015 11:30:28 +0000 (12:30 +0100)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 16 Nov 2015 11:04:18 +0000 (12:04 +0100)
commitc7e8b2c21c6a6fd88022ae64f997ebc574036067
tree4e625e806cfb7c30e8053a7e88ad04f4aa83b7a4
parentf07f21b3e20c11017cea17ec841f0150a62aac53
s390: avoid cache aliasing under z/VM and KVM

commit 1f6b83e5e4d3 ("s390: avoid z13 cache aliasing") checks for the
machine type to optimize address space randomization and zero page
allocation to avoid cache aliases.

This check might fail under a hypervisor with migration support.
z/VMs "Single System Image and Live Guest Relocation" facility will
"fake" the machine type of the oldest system in the group. For example
in a group of zEC12 and Z13 the guest appears to run on a zEC12
(architecture fencing within the relocation domain)

Remove the machine type detection and always use cache aliasing
rules that are known to work for all machines. These are the z13
aliasing rules.

Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/include/asm/elf.h
arch/s390/kernel/process.c
arch/s390/mm/init.c
arch/s390/mm/mmap.c