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authorGreg Kurz <gkurz@linux.vnet.ibm.com>2014-12-12 12:37:40 +0100
committerMichael Ellerman <mpe@ellerman.id.au>2014-12-18 19:59:21 +1100
commitd70a54e2d08510a99b1f10eceeae6f2f7086e226 (patch)
tree2609a216f280aecc8684a9dac4555830d1f794df /arch/powerpc
parent505e428374bc17a2c0bd388c2e8d892e9cd8eef2 (diff)
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 <gkurz@linux.vnet.ibm.com> [mpe: Update comment and change log to be more precise] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/platforms/powernv/smp.c16
1 files changed, 15 insertions, 1 deletions
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,