powerpc/64s/idle: POWER9 implement a separate idle stop function for hotplug

Implement a new function to invoke stop, power9_offline_stop, which is
like power9_idle_stop but used by the cpu hotplug code.

Move KVM secondary state manipulation code to the offline case.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/processor.h

@@ -518,6 +518,7 @@ extern int powersave_nap;	/* set if nap mode can be used in idle loop */
 extern unsigned long power7_idle_insn(unsigned long type); /* PNV_THREAD_NAP/etc*/
 extern void power7_idle_type(unsigned long type);
 extern unsigned long power9_idle_stop(unsigned long psscr_val);
+extern unsigned long power9_offline_stop(unsigned long psscr_val);
 extern void power9_idle_type(unsigned long stop_psscr_val,
 			      unsigned long stop_psscr_mask);
 

arch/powerpc/kernel/idle_book3s.S

@@ -325,12 +325,6 @@ enter_winkle:
  * r3 - PSSCR value corresponding to the requested stop state.
  */
 power_enter_stop:
-#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
-	/* Tell KVM we're entering idle */
-	li	r4,KVM_HWTHREAD_IN_IDLE
-	/* DO THIS IN REAL MODE!  See comment above. */
-	stb	r4,HSTATE_HWTHREAD_STATE(r13)
-#endif
 /*
  * Check if we are executing the lite variant with ESL=EC=0
  */
@@ -425,6 +419,24 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66);		\
 	ld	r3,ORIG_GPR3(r1);	/* Restore original r3 */	\
 20:	nop;
 
+/*
+ * Entered with MSR[EE]=0 and no soft-masked interrupts pending.
+ * r3 contains desired PSSCR register value.
+ */
+_GLOBAL(power9_offline_stop)
+	std	r3, PACA_REQ_PSSCR(r13)
+	mtspr 	SPRN_PSSCR,r3
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+	/* Tell KVM we're entering idle */
+	li	r4,KVM_HWTHREAD_IN_IDLE
+	/* DO THIS IN REAL MODE!  See comment above. */
+	stb	r4,HSTATE_HWTHREAD_STATE(r13)
+#endif
+	LOAD_REG_ADDR(r4,power_enter_stop)
+	b	pnv_powersave_common
+	/* No return */
+
+
 /*
  * Entered with MSR[EE]=0 and no soft-masked interrupts pending.
  * r3 contains desired PSSCR register value.

arch/powerpc/platforms/powernv/idle.c

@@ -511,7 +511,7 @@ unsigned long pnv_cpu_offline(unsigned int cpu)
 		psscr = mfspr(SPRN_PSSCR);
 		psscr = (psscr & ~pnv_deepest_stop_psscr_mask) |
 						pnv_deepest_stop_psscr_val;
-		srr1 = power9_idle_stop(psscr);
+		srr1 = power9_offline_stop(psscr);
 
 	} else if ((idle_states & OPAL_PM_WINKLE_ENABLED) &&
 		   (idle_states & OPAL_PM_LOSE_FULL_CONTEXT)) {