ARM: socfpga: add smp_ops.cpu_kill to make kexec/kdump available

Kexec_load syscall in ARM requires that machine-specific code
has the smp_ops.cpu_kill() before loading kernel image.
This patch adds the cpu_kill(), as a result, kexec reboot and
kernel crash dump become available in mach-socfpga.

Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Link: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/348004.html
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>

diff --git a/arch/arm/mach-socfpga/platsmp.c b/arch/arm/mach-socfpga/platsmp.c
index c6f1df89f9af7fdf10049805714c4f5045165dc2..15c8ce8965f43c3997e37e9d093e4675ae9bd589 100644 (file)
--- a/arch/arm/mach-socfpga/platsmp.c
+++ b/arch/arm/mach-socfpga/platsmp.c
@@ -106,11 +106,23 @@ static void socfpga_cpu_die(unsigned int cpu)
                cpu_do_idle();
 }
 
+/*
+ * We need a dummy function so that platform_can_cpu_hotplug() knows
+ * we support CPU hotplug. However, the function does not need to do
+ * anything, because CPUs going offline just do WFI. We could reset
+ * the CPUs but it would increase power consumption.
+ */
+static int socfpga_cpu_kill(unsigned int cpu)
+{
+       return 1;
+}
+
 static struct smp_operations socfpga_smp_ops __initdata = {
        .smp_prepare_cpus       = socfpga_smp_prepare_cpus,
        .smp_boot_secondary     = socfpga_boot_secondary,
 #ifdef CONFIG_HOTPLUG_CPU
        .cpu_die                = socfpga_cpu_die,
+       .cpu_kill               = socfpga_cpu_kill,
 #endif
 };
 
@@ -119,6 +131,7 @@ static struct smp_operations socfpga_a10_smp_ops __initdata = {
        .smp_boot_secondary     = socfpga_a10_boot_secondary,
 #ifdef CONFIG_HOTPLUG_CPU
        .cpu_die                = socfpga_cpu_die,
+       .cpu_kill               = socfpga_cpu_kill,
 #endif
 };