ACPI: Rename ACPI_HOTPLUG_CPU to include 'present'

The code behind ACPI_HOTPLUG_CPU allows a not-present CPU to become
present. This isn't the only use of HOTPLUG_CPU. On arm64 and riscv
CPUs can be taken offline as a power saving measure.

On arm64 an offline CPU may be disabled by firmware, preventing it from
being brought back online, but it remains present throughout.

Adding code to prevent user-space trying to online these disabled CPUs
needs some additional terminology.

Rename the Kconfig symbol CONFIG_ACPI_HOTPLUG_PRESENT_CPU to reflect
that it makes possible CPUs present.

HOTPLUG_CPU is untouched as this is only about the ACPI mechanism.

Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
 * Add Loongarch update
Changes since RFC v3:
 * Dropped ia64 changes
Changes since RFC v3 (smaller series):
 * Corrected indentation

8 files changed, 12 insertions, 12 deletions

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 10959e6c3583..2aeff9ffcb47 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -5,7 +5,7 @@ config LOONGARCH
 	select ACPI
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_MCFG if ACPI
-	select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
+	select ACPI_HOTPLUG_PRESENT_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
 	select ACPI_PPTT if ACPI
 	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
 	select ARCH_BINFMT_ELF_STATE
diff --git a/arch/loongarch/configs/loongson3_defconfig b/arch/loongarch/configs/loongson3_defconfig
index f18c2ba871ef..f5a46dc2e039 100644
--- a/arch/loongarch/configs/loongson3_defconfig
+++ b/arch/loongarch/configs/loongson3_defconfig
@@ -63,7 +63,7 @@ CONFIG_ACPI_SPCR_TABLE=y
 CONFIG_ACPI_TAD=y
 CONFIG_ACPI_DOCK=y
 CONFIG_ACPI_IPMI=m
-CONFIG_ACPI_HOTPLUG_CPU=y
+CONFIG_ACPI_HOTPLUG_PRESENT_CPU=y
 CONFIG_ACPI_PCI_SLOT=y
 CONFIG_ACPI_HOTPLUG_MEMORY=y
 CONFIG_VIRTUALIZATION=y
diff --git a/arch/loongarch/kernel/acpi.c b/arch/loongarch/kernel/acpi.c
index b6b097bbf866..dcf921b2062c 100644
--- a/arch/loongarch/kernel/acpi.c
+++ b/arch/loongarch/kernel/acpi.c
@@ -288,7 +288,7 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size)
 	memblock_reserve(addr, size);
 }
 
-#ifdef CONFIG_ACPI_HOTPLUG_CPU
+#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU
 
 #include <acpi/processor.h>
 
@@ -340,4 +340,4 @@ int acpi_unmap_cpu(int cpu)
 }
 EXPORT_SYMBOL(acpi_unmap_cpu);
 
-#endif /* CONFIG_ACPI_HOTPLUG_CPU */
+#endif /* CONFIG_ACPI_HOTPLUG_PRESENT_CPU */
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5edec175b9bf..cc220f32d470 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -59,7 +59,7 @@ config X86
 	#
 	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
 	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
-	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
+	select ACPI_HOTPLUG_PRESENT_CPU		if ACPI_PROCESSOR && HOTPLUG_CPU
 	select ARCH_32BIT_OFF_T			if X86_32
 	select ARCH_CLOCKSOURCE_INIT
 	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 85a3ce2a3666..d475bc42b914 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -827,7 +827,7 @@ static void __init acpi_set_irq_model_ioapic(void)
 /*
  *  ACPI based hotplug support for CPU
  */
-#ifdef CONFIG_ACPI_HOTPLUG_CPU
+#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU
 #include <acpi/processor.h>
 
 static int acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
@@ -876,7 +876,7 @@ int acpi_unmap_cpu(int cpu)
 	return (0);
 }
 EXPORT_SYMBOL(acpi_unmap_cpu);
-#endif				/* CONFIG_ACPI_HOTPLUG_CPU */
+#endif				/* CONFIG_ACPI_HOTPLUG_PRESENT_CPU */
 
 int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base)
 {
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 3c3f8037ebed..deea382990b7 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -310,7 +310,7 @@ config ACPI_IPMI
 	  To compile this driver as a module, choose M here:
 	  the module will be called as acpi_ipmi.
 
-config ACPI_HOTPLUG_CPU
+config ACPI_HOTPLUG_PRESENT_CPU
 	bool
 	depends on ACPI_PROCESSOR && HOTPLUG_CPU
 	select ACPI_CONTAINER
@@ -405,7 +405,7 @@ config ACPI_PCI_SLOT
 
 config ACPI_CONTAINER
 	bool "Container and Module Devices"
-	default (ACPI_HOTPLUG_MEMORY || ACPI_HOTPLUG_CPU)
+	default (ACPI_HOTPLUG_MEMORY || ACPI_HOTPLUG_PRESENT_CPU)
 	help
 	  This driver supports ACPI Container and Module devices (IDs
 	  ACPI0004, PNP0A05, and PNP0A06).
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 5e641180c45a..7a928777ad1a 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -189,7 +189,7 @@ static int acpi_processor_make_present(struct acpi_processor *pr)
 	acpi_status status;
 	int ret;
 
-	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_CPU)) {
+	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
 		pr_err_once("Changing CPU present bit is not supported\n");
 		return -ENODEV;
 	}
@@ -490,7 +490,7 @@ static void acpi_processor_make_not_present(struct acpi_device *device)
 {
 	struct acpi_processor *pr;
 
-	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_CPU)) {
+	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
 		pr_err_once("Changing CPU present bit is not supported");
 		return;
 	}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index cf018d42e632..18d1537c08db 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -646,7 +646,7 @@ static inline u32 acpi_osc_ctx_get_cxl_control(struct acpi_osc_context *context)
 #define ACPI_GSB_ACCESS_ATTRIB_RAW_PROCESS	0x0000000F
 
 /* Enable _OST when all relevant hotplug operations are enabled */
-#if defined(CONFIG_ACPI_HOTPLUG_CPU) &&			\
+#if defined(CONFIG_ACPI_HOTPLUG_PRESENT_CPU) &&		\
 	defined(CONFIG_ACPI_HOTPLUG_MEMORY) &&		\
 	defined(CONFIG_ACPI_CONTAINER)
 #define ACPI_HOTPLUG_OST