From: Srivatsa S. Bhat Date: Tue, 21 May 2013 09:32:48 +0000 (+0000) Subject: powerpc/pseries: Always enable CONFIG_HOTPLUG_CPU on PSERIES SMP X-Git-Tag: firefly_0821_release~3680^2~378^2~5 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f274ef8747d3be649bba8708696fb31cb00fa75a;p=firefly-linux-kernel-4.4.55.git 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: Adam Lackorzynski Cc: stable@vger.kernel.org Signed-off-by: Srivatsa S. Bhat Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index 023b288f895b..4459eff7a75a 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -19,6 +19,8 @@ config PPC_PSERIES select ZLIB_DEFLATE select PPC_DOORBELL select HAVE_CONTEXT_TRACKING + select HOTPLUG if SMP + select HOTPLUG_CPU if SMP default y config PPC_SPLPAR