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LoongArch: Switch over to GENERIC_CPU_DEVICES 

Now that GENERIC_CPU_DEVICES calls arch_register_cpu(), which can be
overridden by the arch code, switch over to this to allow common code
to choose when the register_cpu() call is made.

This allows topology_init() to be removed.

This is an intermediate step to the logic being moved to drivers/acpi,
where GENERIC_CPU_DEVICES will do the work when booting with acpi=off.

This is a subtle change. Originally:
- on boot, topology_init() would have marked present CPUs that
  io_master() is true for as hotplug-incapable.
- if a CPU is hotplugged that is an io_master(), it can later be
  hot-unplugged.

The new behaviour is that any CPU that io_master() is true for will
now always be marked as hotplug-incapable, thus even if it was
hotplugged, it can no longer be hot-unplugged.

This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R41-00Ct04-Bg@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
James Morse 2023-11-21 13:45:17 +00:00 committed by Greg Kroah-Hartman
parent e850a5c406
commit db3ba29a83
2 changed files with 3 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/loongarch/Kconfig
View File

@ -72,6 +72,7 @@ config LOONGARCH
select GENERIC_CLOCKEVENTS
select GENERIC_CMOS_UPDATE
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_DEVICES
select GENERIC_ENTRY
select GENERIC_GETTIMEOFDAY
select GENERIC_IOREMAP if !ARCH_IOREMAP

29
arch/loongarch/kernel/topology.c
View File

@ -10,20 +10,13 @@
#include <acpi/processor.h>
static DEFINE_PER_CPU(struct cpu, cpu_devices);
#ifdef CONFIG_HOTPLUG_CPU
int arch_register_cpu(int cpu)
{
int ret;
struct cpu *c = &per_cpu(cpu_devices, cpu);
c->hotpluggable = 1;
ret = register_cpu(c, cpu);
if (ret < 0)
pr_warn("register_cpu %d failed (%d)\n", cpu, ret);
return ret;
c->hotpluggable = !io_master(cpu);
return register_cpu(c, cpu);
}
void arch_unregister_cpu(int cpu)
@ -34,21 +27,3 @@ void arch_unregister_cpu(int cpu)
unregister_cpu(c);
}
#endif
static int __init topology_init(void)
{
int i, ret;
for_each_present_cpu(i) {
struct cpu *c = &per_cpu(cpu_devices, i);
c->hotpluggable = !io_master(i);
ret = register_cpu(c, i);
if (ret < 0)
pr_warn("topology_init: register_cpu %d failed (%d)\n", i, ret);
}
return 0;
}
subsys_initcall(topology_init);