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: v3.10-rc4~2^2~5 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f274ef8747d3be649bba8708696fb31cb00fa75a;p=pandora-kernel.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 --- Reading git-diff-tree failed