diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 7439b2377df5799e371669faa7cc96229dadca38..8e9dd63b220c68f1f9cbb4cfa470192900ea10f2 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -467,11 +467,6 @@ smp_prepare_cpus(unsigned int max_cpus)
smp_num_cpus = smp_num_probed;
}
-void
-smp_prepare_boot_cpu(void)
-{
-}
-
int
__cpu_up(unsigned int cpu, struct task_struct *tidle)
{
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 8d9b188caa27bcd965cd3f94a6a4a4739657c97d..b2f2c59279a6799ad89daf3ce709b8d010915920 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -39,11 +39,6 @@ struct plat_smp_ops __weak plat_smp_ops;
/* XXX: per cpu ? Only needed once in early secondary boot */
struct task_struct *secondary_idle_tsk;
-/* Called from start_kernel */
-void __init smp_prepare_boot_cpu(void)
-{
-}
-
static int __init arc_get_cpu_map(const char *name, struct cpumask *cpumask)
{
unsigned long dt_root = of_get_flat_dt_root();
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 8e42352cbf123f4bc771dfefda013bf12d818cfa..92dbbf3e0205b61bb9b89697750e501a22747390 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -152,10 +152,6 @@ void arch_irq_work_raise(void)
}
#endif
-void __init smp_prepare_boot_cpu(void)
-{
-}
-
void __init smp_prepare_cpus(unsigned int max_cpus)
{
}
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 608884bc3396763eefcc4dc44896322a89da6763..65e1fdf9fdb21d730c36675d0ffdac287db8252f 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -114,10 +114,6 @@ void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg)
local_irq_restore(flags);
}
-void __init smp_prepare_boot_cpu(void)
-{
-}
-
/*
* interrupts should already be disabled from the VM
* SP should already be correct; need to set THREADINFO_REG
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index 1c5a2d71d6753e8a02a8903712c163802e56891c..86da4bc5ee0bbeb7fbc2a36a3275a271624feffe 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -57,10 +57,6 @@ static void boot_secondary(unsigned int cpu, struct task_struct *idle)
spin_unlock(&boot_lock);
}
-void __init smp_prepare_boot_cpu(void)
-{
-}
-
void __init smp_init_cpus(void)
{
struct device_node *cpu;
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 519b6bd946e5d1b69edf3379e31b345e38a03deb..c4ed7d977f57b2c305e5ecbf2b767fd9b0c175df 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -42,10 +42,6 @@
static DECLARE_COMPLETION(cpu_running);
-void __init smp_prepare_boot_cpu(void)
-{
-}
-
void __init smp_prepare_cpus(unsigned int max_cpus)
{
int cpuid;
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index f3969a3600dbfe4931a18d95da4e2ee8fb53503f..a0cc9bb41a921cb3acd74c50a40f663bc042f2e3 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1206,10 +1206,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
{
}
-void smp_prepare_boot_cpu(void)
-{
-}
-
void __init smp_setup_processor_id(void)
{
if (tlb_type == spitfire)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 4fab2ed454f3ab86a636ec9d2ac1ed682d1de624..31edeab5ee88fa03c84c208c119824127f33fd0a 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -59,11 +59,6 @@ static inline void stop_other_cpus(void)
smp_ops.stop_other_cpus(1);
}
-static inline void smp_prepare_boot_cpu(void)
-{
- smp_ops.smp_prepare_boot_cpu();
-}
-
static inline void smp_prepare_cpus(unsigned int max_cpus)
{
smp_ops.smp_prepare_cpus(max_cpus);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 3f57ce68a3f1ec9c6fe742c08a008d89f65f3f97..980782bd2c976f380caad08d1a0442874b32bb25 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1187,6 +1187,11 @@ void __init smp_prepare_cpus_common(void)
set_cpu_sibling_map(0);
}
+void __init smp_prepare_boot_cpu(void)
+{
+ smp_ops.smp_prepare_boot_cpu();
+}
+
#ifdef CONFIG_X86_64
/* Establish whether parallel bringup can be supported. */
bool __init arch_cpuhp_init_parallel_bringup(void)
diff --git a/include/linux/smp.h b/include/linux/smp.h
index e87520dc2959dd9bd047ed2740945fd20bf7fd9a..b84592950149e20409151e3fd02eec692bee8842 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -105,6 +105,12 @@ static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
}
+/*
+ * Architecture specific boot CPU setup. Defined as empty weak function in
+ * init/main.c. Architectures can override it.
+ */
+void smp_prepare_boot_cpu(void);
+
#ifdef CONFIG_SMP
#include <linux/preempt.h>
@@ -171,12 +177,6 @@ void generic_smp_call_function_single_interrupt(void);
#define generic_smp_call_function_interrupt \
generic_smp_call_function_single_interrupt
-/*
- * Mark the boot cpu "online" so that it can call console drivers in
- * printk() and can access its per-cpu storage.
- */
-void smp_prepare_boot_cpu(void);
-
extern unsigned int setup_max_cpus;
extern void __init setup_nr_cpu_ids(void);
extern void __init smp_init(void);
@@ -203,7 +203,6 @@ static inline void up_smp_call_function(smp_call_func_t func, void *info)
(up_smp_call_function(func, info))
static inline void smp_send_reschedule(int cpu) { }
-#define smp_prepare_boot_cpu() do {} while (0)
#define smp_call_function_many(mask, func, info, wait) \
(up_smp_call_function(func, info))
static inline void call_function_init(void) { }
diff --git a/init/main.c b/init/main.c
index e24b0780fdff7a807bd027ab26e61fc303c624ef..d60bc4b23dd47024bd66c8b04f1217bd374b2c80 100644
--- a/init/main.c
+++ b/init/main.c
@@ -776,6 +776,10 @@ void __init __weak smp_setup_processor_id(void)
{
}
+void __init __weak smp_prepare_boot_cpu(void)
+{
+}
+
# if THREAD_SIZE >= PAGE_SIZE
void __init __weak thread_stack_cache_init(void)
{