The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings. In any case, they are temporary and harmless.
This removes all the ARM uses of the __cpuinit macros from C code,
and all __CPUINIT from assembly code. It also had two ".previous"
section statements that were paired off against __CPUINIT
(aka .section ".cpuinit.text") that also get removed here.
[1] https://lkml.org/lkml/2013/5/20/589
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The ->smp_init_cpus() function is called very early during boot, at a
point where dynamic I/O mappings are not yet possible. However, in the
Armada 370/XP implementation of this function, we have to get the
number of CPUs. We used to do that by accessing a hardware register,
which requires relying on a static I/O mapping set up by
->map_io(). Not only this requires hardcoding a virtual address, but
it also prevents us from removing the static I/O mapping.
So this commit changes the way used to get the number of CPUs: we now
use the Device Tree, which is a representation of the hardware, and
provides us the number of available CPUs. This is also more accurate,
because it potentially allows to boot the Linux kernel on only a
number of CPUs given by the Device Tree, instead of unconditionally on
all CPUs.
As a consequence, the coherency_get_cpu_count() function becomes no
longer used, so we remove it.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
The changes needed to migrate the mach-mvebu (Armada 370 and Armada
XP) to the mvebu-mbus driver are fairly minimal, since not many
devices currently supported on those SoCs use address decoding
windows. The only one being the BootROM window, used to bring up
secondary CPUs.
However, this BootROM window needed for SMP brings an important
requirement: the mvebu-mbus driver must be initialized at the
->early_init() time, otherwise the BootROM window cannot be setup
early enough to be ready before the secondary CPUs are started.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
This enables SMP support on the Armada XP processor. It adds the
mandatory functions to support SMP such as: the SMP initialization
functions in platsmp.c, the secondary CPU entry point in headsmp.S and
the CPU hotplug initial support in hotplug.c.
Signed-off-by: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Paul Gortmaker