s390/bp: remove __bpon()

There is no point in changing branch prediction state of a cpu shortly
before it enters stop state. Therefore remove __bpon().
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/processor.h

@@ -99,7 +99,6 @@ void cpu_detect_mhz_feature(void);
 
 extern const struct seq_operations cpuinfo_op;
 extern void execve_tail(void);
-extern void __bpon(void);
 unsigned long vdso_size(void);
 
 /*

arch/s390/kernel/entry.S

@@ -159,21 +159,15 @@ _LPP_OFFSET	= __LC_LPP
 	.section .kprobes.text, "ax"
 .Ldummy:
 	/*
-	 * This nop exists only in order to avoid that __bpon starts at
-	 * the beginning of the kprobes text section. In that case we would
-	 * have several symbols at the same address. E.g. objdump would take
-	 * an arbitrary symbol name when disassembling this code.
-	 * With the added nop in between the __bpon symbol is unique
-	 * again.
+	 * The following nop exists only in order to avoid that the next
+	 * symbol starts at the beginning of the kprobes text section.
+	 * In that case there would be several symbols at the same address.
+	 * E.g. objdump would take an arbitrary symbol when disassembling
+	 * the code.
+	 * With the added nop in between this cannot happen.
 	 */
 	nop	0
 
-ENTRY(__bpon)
-	.globl __bpon
-	BPON
-	BR_EX	%r14
-ENDPROC(__bpon)
-
 /*
  * Scheduler resume function, called by switch_to
  *  gpr2 = (task_struct *) prev

arch/s390/kernel/ipl.c

@@ -649,7 +649,6 @@ static struct kset *ipl_kset;
 
 static void __ipl_run(void *unused)
 {
-	__bpon();
 	diag308(DIAG308_LOAD_CLEAR, NULL);
 }
 

arch/s390/kernel/smp.c

@@ -348,7 +348,6 @@ static void pcpu_delegate(struct pcpu *pcpu,
 		abs_lc->restart_source = source_cpu;
 		put_abs_lowcore(abs_lc);
 	}
-	__bpon();
 	asm volatile(
 		"0:	sigp	0,%0,%2	# sigp restart to target cpu\n"
 		"	brc	2,0b	# busy, try again\n"
@@ -986,7 +985,6 @@ void __cpu_die(unsigned int cpu)
 void __noreturn cpu_die(void)
 {
 	idle_task_exit();
-	__bpon();
 	pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 	for (;;) ;
 }