From d70a54e2d08510a99b1f10eceeae6f2f7086e226 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Fri, 12 Dec 2014 12:37:40 +0100 Subject: powerpc/powernv: Ignore smt-enabled on Power8 and later Starting with POWER8, the subcore logic relies on all threads of a core being booted so that they can participate in split mode switches. So on those machines we ignore the smt_enabled_at_boot setting (smt-enabled on the kernel command line). Signed-off-by: Greg Kurz [mpe: Update comment and change log to be more precise] Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/powernv/smp.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/platforms/powernv/smp.c') diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index 6c551a28e899..fc34025ef822 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -209,13 +209,27 @@ static void pnv_smp_cpu_kill_self(void) #endif /* CONFIG_HOTPLUG_CPU */ +static int pnv_cpu_bootable(unsigned int nr) +{ + /* + * Starting with POWER8, the subcore logic relies on all threads of a + * core being booted so that they can participate in split mode + * switches. So on those machines we ignore the smt_enabled_at_boot + * setting (smt-enabled on the kernel command line). + */ + if (cpu_has_feature(CPU_FTR_ARCH_207S)) + return 1; + + return smp_generic_cpu_bootable(nr); +} + static struct smp_ops_t pnv_smp_ops = { .message_pass = smp_muxed_ipi_message_pass, .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */ .probe = xics_smp_probe, .kick_cpu = pnv_smp_kick_cpu, .setup_cpu = pnv_smp_setup_cpu, - .cpu_bootable = smp_generic_cpu_bootable, + .cpu_bootable = pnv_cpu_bootable, #ifdef CONFIG_HOTPLUG_CPU .cpu_disable = pnv_smp_cpu_disable, .cpu_die = generic_cpu_die, -- cgit v1.2.3