s390/mm: Restore mapping of kernel image using large pages

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Since physical and virtual kernel address spaces are uncoupled
the kernel image is not mapped using large segment pages anymore,
which is a regression.

Put the kernel image at the same large segment page offset in
physical memory as in virtual memory. Such approach preserves
the existing number of bits of entropy used for randomization
of the kernel location in virtual memory when KASLR is on.
As result, the kernel is mapped using large segment pages.

Fixes: c98d2ecae0 ("s390/mm: Uncouple physical vs virtual address spaces")
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

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Alexander Gordeev 2024-06-07 14:19:50 +02:00 • committed by Vasily Gorbik

parent d8073dc6bc

commit 693d41f7c9

3 changed files with 26 additions and 4 deletions

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27

arch/s390/boot/startup.c

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2

arch/s390/boot/vmem.c

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1

arch/s390/boot/vmlinux.lds.S

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