[PATCH 2/2] cpu: Register a generic CPU device on architectures that currently do not

[Ben Hutchings <ben@decadent.org.uk>]

frv, h8300, microblaze, openrisc, score and xtensa currently do not
register a CPU device.  Add the config option GENERIC_CPU_DEVICES which
causes a generic CPU device to be registered for each present CPU, and
make all these architectures select it.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
This is untested on any of the affected architectures.  However, I
bodged x86 to use this option rather than registering CPU devices, and
the resulting kernel booted and showed the expected things in sysfs.

There are several other architectures that could be changed to use this
option, but I don't want to combine that change with this.

Ben.

 arch/frv/Kconfig        |    1 +
 arch/h8300/Kconfig      |    1 +
 arch/m68k/Kconfig       |    1 +
 arch/microblaze/Kconfig |    1 +
 arch/openrisc/Kconfig   |    1 +
 arch/score/Kconfig      |    1 +
 arch/xtensa/Kconfig     |    1 +
 drivers/base/Kconfig    |    4 ++++
 drivers/base/cpu.c      |   26 +++++++++++++++++++++++++-
 9 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index bad27a6..70554ba 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -8,6 +8,7 @@ config FRV
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_IRQ_SHOW
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select GENERIC_CPU_DEVICES
 
 config ZONE_DMA
 	bool
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index d1f377f..56e890d 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -4,6 +4,7 @@ config H8300
 	select HAVE_IDE
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_IRQ_SHOW
+	select GENERIC_CPU_DEVICES
 
 config SYMBOL_PREFIX
 	string
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 81fdaa7..f755ecf 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -6,6 +6,7 @@ config M68K
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_IRQ_SHOW
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS
+	select GENERIC_CPU_DEVICES
 
 config RWSEM_GENERIC_SPINLOCK
 	bool
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index e446bab..16ca257 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -17,6 +17,7 @@ config MICROBLAZE
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
+	select GENERIC_CPU_DEVICES
 
 config SWAP
 	def_bool n
diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index e518a5a..978e0bd 100644
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -15,6 +15,7 @@ config OPENRISC
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IOMAP
+	select GENERIC_CPU_DEVICES
 
 config MMU
 	def_bool y
diff --git a/arch/score/Kconfig b/arch/score/Kconfig
index 8b0c946..51cbf1e 100644
--- a/arch/score/Kconfig
+++ b/arch/score/Kconfig
@@ -7,6 +7,7 @@ config SCORE
        select HAVE_MEMBLOCK
        select HAVE_MEMBLOCK_NODE_MAP
        select ARCH_DISCARD_MEMBLOCK
+       select GENERIC_CPU_DEVICES
 
 choice
 	prompt "System type"
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index c346ccd..8a3f835 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -9,6 +9,7 @@ config XTENSA
 	select HAVE_IDE
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_IRQ_SHOW
+	select GENERIC_CPU_DEVICES
 	help
 	  Xtensa processors are 32-bit RISC machines designed by Tensilica
 	  primarily for embedded systems.  These processors are both
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 21cf46f..4ebc5d3 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -172,6 +172,10 @@ config SYS_HYPERVISOR
 	bool
 	default n
 
+config GENERIC_CPU_DEVICES
+	bool
+	default n
+
 source "drivers/base/regmap/Kconfig"
 
 endmenu
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 9a5578e..246f3b3 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -10,6 +10,7 @@
 #include <linux/device.h>
 #include <linux/node.h>
 #include <linux/gfp.h>
+#include <linux/slab.h>
 
 #include "base.h"
 
@@ -274,6 +275,26 @@ bool cpu_is_hotpluggable(unsigned cpu)
 }
 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
 
+static int cpu_dev_register_generic(void)
+{
+#ifdef CONFIG_GENERIC_CPU_DEVICES
+	struct cpu *cpu_devices;
+	int err;
+	int i;
+
+	cpu_devices = kcalloc(nr_cpu_ids, sizeof(cpu_devices[0]), GFP_KERNEL);
+	if (!cpu_devices)
+		return -ENOMEM;
+
+	for_each_possible_cpu(i) {
+		err = register_cpu(&cpu_devices[i], i);
+		if (err)
+			return err;
+	}
+#endif
+	return 0;
+}
+
 int __init cpu_dev_init(void)
 {
 	int err;
@@ -284,6 +305,9 @@ int __init cpu_dev_init(void)
 
 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
 	err = sched_create_sysfs_power_savings_entries(cpu_subsys.dev_root);
+	if (err)
+		return err;
 #endif
-	return err;
+
+	return cpu_dev_register_generic();
 }
-- 
1.7.8.2