linux-kernel - [RFC 02/10] cpu/hotplug: Compile smp_shutdown_nonboot_cpus() conditioned on CONFIG_SHUTDOWN_NONBOOT

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Date:   Mon, 22 Aug 2022 10:15:12 +0800
From:   Pingfan Liu <kernelfans@...il.com>
To:     linux-arm-kernel@...ts.infradead.org, linux-ia64@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Pingfan Liu <kernelfans@...il.com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Peter Zijlstra <peterz@...radead.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Mark Rutland <mark.rutland@....com>,
        Marco Elver <elver@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Dan Li <ashimida@...ux.alibaba.com>,
        Song Liu <song@...nel.org>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Arnd Bergmann <arnd@...db.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        Nick Hawkins <nick.hawkins@....com>,
        John Crispin <john@...ozen.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Steven Price <steven.price@....com>
Subject: [RFC 02/10] cpu/hotplug: Compile smp_shutdown_nonboot_cpus() conditioned on CONFIG_SHUTDOWN_NONBOOT_CPUS

Only arm/arm64/ia64/riscv share the smp_shutdown_nonboot_cpus(). So
compiling this code conditioned on the macro
CONFIG_SHUTDOWN_NONBOOT_CPUS. Later this macro will brace the quick
kexec reboot code.

Signed-off-by: Pingfan Liu <kernelfans@...il.com>
Cc: Russell King <linux@...linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Paul Walmsley <paul.walmsley@...ive.com>
Cc: Palmer Dabbelt <palmer@...belt.com>
Cc: Albert Ou <aou@...s.berkeley.edu>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Marco Elver <elver@...gle.com>
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Dan Li <ashimida@...ux.alibaba.com>
Cc: Song Liu <song@...nel.org>
Cc: Sami Tolvanen <samitolvanen@...gle.com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Linus Walleij <linus.walleij@...aro.org>
Cc: Ard Biesheuvel <ardb@...nel.org>
Cc: Tony Lindgren <tony@...mide.com>
Cc: Nick Hawkins <nick.hawkins@....com>
Cc: John Crispin <john@...ozen.org>
Cc: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Bjorn Andersson <bjorn.andersson@...aro.org>
Cc: Anshuman Khandual <anshuman.khandual@....com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Steven Price <steven.price@....com>
To: linux-arm-kernel@...ts.infradead.org
To: linux-ia64@...r.kernel.org
To: linux-riscv@...ts.infradead.org
To: linux-kernel@...r.kernel.org
---
 arch/Kconfig       | 4 ++++
 arch/arm/Kconfig   | 1 +
 arch/arm64/Kconfig | 1 +
 arch/ia64/Kconfig  | 1 +
 arch/riscv/Kconfig | 1 +
 kernel/cpu.c       | 3 +++
 6 files changed, 11 insertions(+)

diff --git a/arch/Kconfig b/arch/Kconfig
index f330410da63a..be447537d0f6 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -14,6 +14,10 @@ menu "General architecture-dependent options"
 config CRASH_CORE
 	bool
 
+config SHUTDOWN_NONBOOT_CPUS
+	select KEXEC_CORE
+	bool
+
 config KEXEC_CORE
 	select CRASH_CORE
 	bool
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 87badeae3181..711cfdb4f9f4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -129,6 +129,7 @@ config ARM
 	select PCI_SYSCALL if PCI
 	select PERF_USE_VMALLOC
 	select RTC_LIB
+	select SHUTDOWN_NONBOOT_CPUS
 	select SYS_SUPPORTS_APM_EMULATION
 	select THREAD_INFO_IN_TASK
 	select HAVE_ARCH_VMAP_STACK if MMU && ARM_HAS_GROUP_RELOCS
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 571cc234d0b3..8c481a0b1829 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -223,6 +223,7 @@ config ARM64
 	select PCI_SYSCALL if PCI
 	select POWER_RESET
 	select POWER_SUPPLY
+	select SHUTDOWN_NONBOOT_CPUS
 	select SPARSE_IRQ
 	select SWIOTLB
 	select SYSCTL_EXCEPTION_TRACE
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 26ac8ea15a9e..8a3ddea97d1b 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -52,6 +52,7 @@ config IA64
 	select ARCH_CLOCKSOURCE_DATA
 	select GENERIC_TIME_VSYSCALL
 	select LEGACY_TIMER_TICK
+	select SHUTDOWN_NONBOOT_CPUS
 	select SWIOTLB
 	select SYSCTL_ARCH_UNALIGN_NO_WARN
 	select HAVE_MOD_ARCH_SPECIFIC
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index ed66c31e4655..02606a48c5ea 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -120,6 +120,7 @@ config RISCV
 	select PCI_MSI if PCI
 	select RISCV_INTC
 	select RISCV_TIMER if RISCV_SBI
+	select SHUTDOWN_NONBOOT_CPUS
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 338e1d426c7e..2be6ba811a01 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1258,6 +1258,8 @@ int remove_cpu(unsigned int cpu)
 }
 EXPORT_SYMBOL_GPL(remove_cpu);
 
+#ifdef CONFIG_SHUTDOWN_NONBOOT_CPUS
+
 void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
 {
 	unsigned int cpu;
@@ -1299,6 +1301,7 @@ void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
 
 	cpu_maps_update_done();
 }
+#endif
 
 #else
 #define takedown_cpu		NULL
-- 
2.31.1