In the old days, _PAGE_EXEC didn't exist on 6xx aka book3s/32.
Therefore, allthough __mapin_ram_chunk() was already mapping kernel
text with PAGE_KERNEL_TEXT and the rest with PAGE_KERNEL, the entire
memory was executable. Part of the memory (first 512kbytes) was
mapped with BATs instead of page table, but it was also entirely
mapped as executable.
In commit 385e89d5b2 ("powerpc/mm: add exec protection on
powerpc 603"), we started adding exec protection to some 6xx, namely
the 603, for pages mapped via pagetables.
Then, in commit 63b2bc6195 ("powerpc/mm/32s: Use BATs for
STRICT_KERNEL_RWX"), the exec protection was extended to BAT mapped
memory, so that really only the kernel text could be executed.
The problem here is that kexec is based on copying some code into
upper part of memory then executing it from there in order to install
a fresh new kernel at its definitive location.
However, the code is position independant and first part of it is
just there to deactivate the MMU and jump to the second part. So it
is possible to run this first part inplace instead of running the
copy. Once the MMU is off, there is no protection anymore and the
second part of the code will just run as before.
Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Fixes: 63b2bc6195 ("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Right now just the kexec crash pathway turns turns off the interrupts.
Pull that out and make a generic version for use elsewhere
Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZE, because control
page is used for not only code on some platform. For example in kexec
jump, it is used for data and stack too.
[akpm@linux-foundation.org: unbreak powerpc and arm, finish conversion]
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch merges, to some extent, the PPC32 and PPC64 kexec implementations.
We adopt the PPC32 approach of having ppc_md callbacks for the kexec functions.
The current PPC64 implementation becomes the "default" implementation for PPC64
which platforms can select if they need no special treatment.
I've added these default callbacks to pseries/maple/cell/powermac, this means
iSeries no longer supports kexec - but it never worked anyway.
I've renamed PPC32's machine_kexec_simple to default_machine_kexec, inline with
PPC64. Judging by the comments it might be better named machine_kexec_non_of,
or something, but at the moment it's the only implementation for PPC32 so it's
the "default".
Kexec requires machine_shutdown(), which is in machine_kexec.c on PPC32, but we
already have in setup-common.c on powerpc. All this does is call
ppc_md.nvram_sync, which only powermac implements, so instead make
machine_shutdown a ppc_md member and have it call core99_nvram_sync directly
on powermac.
I've also stuck relocate_kernel.S into misc_32.S for powerpc.
Built for ARCH=ppc, and 32 & 64 bit ARCH=powerpc, with KEXEC=y/n. Booted on
P5 LPAR and successfully kexec'ed.
Should apply on top of 493f25ef40.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Christophe Leroy