From f274ef8747d3be649bba8708696fb31cb00fa75a Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> Date: Tue, 21 May 2013 09:32:48 +0000 Subject: [PATCH] powerpc/pseries: Always enable CONFIG_HOTPLUG_CPU on PSERIES SMP MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 <adam@os.inf.tu-dresden.de> Cc: stable@vger.kernel.org Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- arch/powerpc/platforms/pseries/Kconfig | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index 023b288f895bf7..4459eff7a75ad6 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 -- GitLab