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-rw-r--r--arch/x86/kernel/head_64.S16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 94bf9cc2c7ee..980053c4b9cc 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -252,6 +252,22 @@ ENTRY(secondary_startup_64)
pushq %rax # target address in negative space
lretq
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
+ * up already except stack. We just set up stack here. Then call
+ * start_secondary().
+ */
+ENTRY(start_cpu0)
+ movq stack_start(%rip),%rsp
+ movq initial_code(%rip),%rax
+ pushq $0 # fake return address to stop unwinder
+ pushq $__KERNEL_CS # set correct cs
+ pushq %rax # target address in negative space
+ lretq
+ENDPROC(start_cpu0)
+#endif
+
/* SMP bootup changes these two */
__REFDATA
.align 8