It turns out that the logical CPU mapping is useful even when !CONFIG_SMP
for manipulation of devices like interrupt and power controllers when
running a UP kernel on a CPU other than 0. This can happen when kexecing
a UP image from an SMP kernel.
In the future, multi-cluster systems running AMP configurations will
require something similar for mapping cluster IDs, so it makes sense to
decouple this logic in preparation for this support.
Acked-by: Yang Bai <hamo.by@gmail.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reported-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'next/cross-platform' of git://git.linaro.org/people/arnd/arm-soc:
arm/imx: use Kconfig choice for low-level debug UART selection
ARM: realview: use Kconfig choice for debug UART selection
ARM: plat-samsung: use Kconfig choice for debug UART selection
ARM: versatile: convert logical CPU numbers to physical numbers
ARM: ux500: convert logical CPU numbers to physical numbers
ARM: shmobile: convert logical CPU numbers to physical numbers
ARM: msm: convert logical CPU numbers to physical numbers
ARM: exynos4: convert logical CPU numbers to physical numbers
Fix up trivial conflict (config DEBUG_S3C_UART move/split vs addition of
ARM_KPROBES_TEST option) in arch/arm/Kconfig.debug
This patch uses the new cpu_logical_map() macro for converting logical
CPU numbers into physical numbers when dealing with the pen_release
variable in the SMP boot and CPU hotplug paths.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Current Versatile Express CPU hotplug code includes a hardcoded WFI
instruction, in ARM encoding. When the kernel is compiled in Thumb-2
mode, this is invalid and causes the machine to hang hard when a CPU
is offlined.
Using the wfi macro (which uses the appropriate assembler mnemonic)
causes the correct instruction to be emitted in either case. As a
consequence of this change, an apparently vestigial "cc" clobber is
dropped from the asm (the macro uses "memory" only).
Signed-off-by: Nick Bowler <nbowler@elliptictech.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Will Deacon
Linus Torvalds
Nick Bowler
Russell King