Commit f274ef87 authored by Srivatsa S. Bhat's avatar Srivatsa S. Bhat Committed by Benjamin Herrenschmidt

powerpc/pseries: Always enable CONFIG_HOTPLUG_CPU on PSERIES SMP

Adam Lackorzynski reported the following build failure on
!CONFIG_HOTPLUG_CPU configuration:

  CC      arch/powerpc/kernel/rtas.o
arch/powerpc/kernel/rtas.c: In function ‘rtas_cpu_state_change_mask’:
arch/powerpc/kernel/rtas.c:843:4: error: implicit declaration of function ‘cpu_down’ [-Werror=implicit-function-declaration]
cc1: all warnings being treated as errors
make[1]: *** [arch/powerpc/kernel/rtas.o] Error 1
make: *** [arch/powerpc/kernel] Error 2

The build fails because cpu_down() is defined only under CONFIG_HOTPLUG_CPU.

Looking further, the mobility code in pseries is one of the call-sites which
uses rtas_ibm_suspend_me(), which in turn calls rtas_cpu_state_change_mask().
And the mobility code is unconditionally compiled-in (it does not fall under
any Kconfig option). And commit 120496ac (powerpc: Bring all threads online
prior to migration/hibernation) which introduced this build regression is
critical for the proper functioning of the migration code. So it appears
that the only solution to this problem is to enable CONFIG_HOTPLUG_CPU if
SMP is enabled on PPC_PSERIES platforms. So make that change in the Kconfig.
Reported-by: default avatarAdam Lackorzynski <adam@os.inf.tu-dresden.de>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 8e44ddc3
...@@ -19,6 +19,8 @@ config PPC_PSERIES ...@@ -19,6 +19,8 @@ config PPC_PSERIES
select ZLIB_DEFLATE select ZLIB_DEFLATE
select PPC_DOORBELL select PPC_DOORBELL
select HAVE_CONTEXT_TRACKING select HAVE_CONTEXT_TRACKING
select HOTPLUG if SMP
select HOTPLUG_CPU if SMP
default y default y
config PPC_SPLPAR config PPC_SPLPAR
......
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