powerpc/powernv: Ignore smt-enabled on Power8 and later (d70a54e2) · Commits · 戴 / test

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>

arch/powerpc/platforms/powernv/smp.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -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,

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