In case of normal kexec kernel load, all cpu's are offlined
before calling machine_kexec().But in case crash panic cpus
are relaxed in machine_crash_nonpanic_core() SMP function
but not offlined.

When crash kernel is loaded with kexec and on panic trigger
machine_kexec() checks for number of cpus online.
If more than one cpu is online machine_kexec() fails to load
with below error

kexec: error: multiple CPUs still online

In machine_crash_nonpanic_core() SMP function, offline CPU
before cpu_relax
Signed-off-by: NVijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Architectures should fully validate whether kexec is possible as part of
machine_kexec_prepare(), so that user-space's kexec_load() operation can
report any problems. Performing validation in machine_kexec() itself is
too late, since it is not allowed to return.

Prior to this patch, ARM's machine_kexec() was testing after-the-fact
whether machine_kexec_prepare() was able to disable all but one CPU.
Instead, modify machine_kexec_prepare() to validate all conditions
necessary for machine_kexec_prepare()'s to succeed. BUG if the validation
succeeded, yet disabling the CPUs didn't actually work.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add comments to machine_shutdown()/halt()/power_off()/restart() that
describe their purpose and/or requirements re: CPUs being active/not.

In machine_shutdown(), replace the call to smp_send_stop() with a call to
disable_nonboot_cpus(). This completely disables all but one CPU, thus
satisfying the requirement that only a single CPU be active for kexec.
Adjust Kconfig dependencies for this change.

In machine_halt()/power_off()/restart(), call smp_send_stop() directly,
rather than via machine_shutdown(); these functions don't need to
completely de-activate all CPUs using hotplug, but rather just quiesce
them.

Remove smp_kill_cpus(), and its call from smp_send_stop().
smp_kill_cpus() was indirectly calling smp_ops.cpu_kill() without calling
smp_ops.cpu_die() on the target CPUs first. At least some implementations
of smp_ops had issues with this; it caused cpu_kill() to hang on Tegra,
for example. Since smp_send_stop() is only used for shutdown, halt, and
power-off, there is no need to attempt any kind of CPU hotplug here.

Adjust Kconfig to reflect that machine_shutdown() (and hence kexec)
relies upon disable_nonboot_cpus(). However, this alone doesn't guarantee
that hotplug will work, or even that hotplug is implemented for a
particular piece of HW that a multi-platform zImage runs on. Hence, add
error-checking to machine_kexec() to determine whether it did work.
Suggested-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NZhangfei Gao <zhangfei.gao@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Commit c564df4d (ARM: 7540/1: kexec:
Check segment memory addresses) added a safety check with accidentally
reversed condition, and broke kexec functionality on ARM. Fix this.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Ensure that the memory regions that are set within the segments
correspond to physical contiguous memory regions.
Reviewed-by: NSimon Horman <horms@verge.net.au>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMatthew Leach <matthew.leach@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch allows a dtb to be passed to a new kernel using the kexec
mechinism.

When loading segments from userspace, scan each segment's first four
bytes for the dtb magic. If this is found set the kexec_boot_atags
parameter to the relocate_kernel code to the phyical address of this
segment.
Reviewed-by: NSimon Horman <horms@verge.net.au>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMatthew Leach <matthew.leach@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Disintegrate asm/system.h for ARM.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Russell King <linux@arm.linux.org.uk>
cc: linux-arm-kernel@lists.infradead.org

The kexec machine crash code can be called in interrupt context via a
sysrq trigger made using the magic key combination. If the irq chip
dealing with the serial interrupt is using the fasteoi flow handler,
then we will never EOI the interrupt because the interrupt handler will
be fatal. In the case of a GIC, this results in the crash kernel not
receiving interrupts on that CPU interface.

This patch adds code (based on the PowerPC implementation) to EOI any
pending interrupts on the crash CPU before masking and disabling all
interrupts. Secondary cores are not a problem since they are placed into
a cpu_relax() loop via an IPI.
Reported-by: NLei Wen <leiwen@marvell.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Now that there is a common way to reset the machine, let's use it
instead of reinventing the wheel in the kexec backend.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

setup_mm_for_reboot() doesn't make use of its argument, so remove it.
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This reverts commit 2b034922.

Will Deacon reports:

This is causing kexec to fail.

The symptoms are that the .init.text section is not loaded as part of the
new kernel image, so when we try to do the SMP/UP fixups we hit a whole sea
of poison left there by the previous kernel.

So my guess is that machine_kexec_prepare *is* too early for preparing the
reboot_code_buffer and, unless anybody has a good reason not to, I'd like to
revert the patch causing these problems.
Reported-by: NWill Deacon <will.deacon@arm.com>

This copy really don't need to do at the very second before the kernel
would crash.
Signed-off-by: NLei Wen <leiwen@marvell.com>
Acked-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Provide the option to call a machine-specific function
before kexec'ing a new kernel.
Signed-off-by: NEric Cooper <ecc@cmu.edu>
Signed-off-by: NNicolas Pitre <nico@fluxnic.net>

When kexec is used to start a crash kernel the other cores
are notified. These non-crashing cores will save their state
in the crash notes and then do nothing.
Signed-off-by: NPer Fransson <per.xx.fransson@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

kexec does not disable the outer cache before disabling the inner
caches in cpu_proc_fin(). So L2 is enabled across the kexec jump. When
the new kernel enables chaches again, it randomly crashes.

Disabling L2 before calling cpu_proc_fin() cures the problem.

Disabling L2 requires the following new functions: flush_all(),
inv_all() and disable(). Add them to outer_cache_fns and call them
from the kexec code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>

x86 calls machine_shutdown() from the various machine_*() calls which
take the machine down ready for halting, restarting, etc, and uses
this to bring the system safely to a point where those actions can be
performed.  Such actions are stopping the secondary CPUs.

So, change the ARM implementation of these to reflect what x86 does.

This solves kexec problems on ARM SMP platforms, where the secondary
CPUs were left running across the kexec call.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

All implementations of cpu_proc_fin() start by disabling interrupts
and then flush caches.  Rather than have every processors proc_fin()
implementation do this, move it out into generic code - and move the
cache flush past setup_mm_for_reboot() (so it can benefit from having
caches still enabled.)

This allows cpu_proc_fin() to become independent of the L1/L2 cache
types, and eventually move the L2 cache flushing into the L2 support
code.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Implement function machine_crash_shutdown() which disables IRQs and
saves machine state to ELF notes structure.
Signed-off-by: NMika Westerberg <ext-mika.1.westerberg@nokia.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The C99 specification states in section 6.11.5:

The placement of a storage-class specifier other than at the beginning of the
declaration specifiers in a declaration is an obsolescent feature.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

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: NHuang 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, the atags used by kexec are fixed to the ones originally used
to boot the kernel. This is less than ideal as changing the commandline,
initrd and other options would be a useful feature.

This patch exports the atags used for the current kernel to userspace
through an "atags" file in procfs. The presence of the file is
controlled by its own Kconfig option and cleans up several ifdef blocks
into a separate file. The tags for the new kernel are assumed to be at
a fixed location before the kernel image itself. The location of the
tags used to boot the original kernel is unimportant and no longer
saved.

Based on a patch from Uli Luckas <u.luckas@road.de>
Signed-off-by: NRichard Purdie <rpurdie@rpsys.net>
Acked-by: NUli Luckas <u.luckas@road.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add kexec support to ARM.

Improvements like commandline handling could be made but this patch gives
basic functional support. It uses the next available syscall number, 347.

Once the syscall number is known, userspace support will be
finalised/submitted to kexec-tools, various patches already exist.

Originally based on a patch by Maxim Syrchin but updated and forward
ported by various people.
Signed-off-by: NRichard Purdie <rpurdie@rpsys.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>