[PATCH 1/6] powernv:idle: Add IDLE_STATE_ENTER_SEQ_NORET macro

[Tim Gardner]

From: "Gautham R. Shenoy" <ego at linux.vnet.ibm.com>

BugLink: http://bugs.launchpad.net/bugs/1666197

Currently all the low-power idle states are expected to wake up
at reset vector 0x100. Which is why the macro IDLE_STATE_ENTER_SEQ
that puts the CPU to an idle state and never returns.

On ISA v3.0, when the ESL and EC bits in the PSSCR are zero, the CPU
is expected to wake up at the next instruction of the idle
instruction.

This patch adds a new macro named IDLE_STATE_ENTER_SEQ_NORET for the
no-return variant and reuses the name IDLE_STATE_ENTER_SEQ for a variant
that allows resuming operation at the instruction next to the
idle-instruction.

Backport of commit 823b7bd5156a ("powernv:idle: Add
IDLE_STATE_ENTER_SEQ_NORET macro")

Signed-off-by: Gautham R. Shenoy <ego at linux.vnet.ibm.com>
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 arch/powerpc/include/asm/cpuidle.h   |  3 +++
 arch/powerpc/kernel/exceptions-64s.S |  6 +++---
 arch/powerpc/kernel/idle_book3s.S    | 10 +++++-----
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h
index 3919332..c91163c 100644
--- a/arch/powerpc/include/asm/cpuidle.h
+++ b/arch/powerpc/include/asm/cpuidle.h
@@ -29,6 +29,9 @@ extern u64 pnv_first_deep_stop_state;
 1:	cmpd	cr0,r0,r0;					\
 	bne	1b;						\
 	IDLE_INST;						\
+
+#define IDLE_STATE_ENTER_SEQ_NORET(IDLE_INST)			\
+	IDLE_STATE_ENTER_SEQ(IDLE_INST)				\
 	b	.
 #endif /* CONFIG_PPC_P7_NAP */
 
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index bffec73..238307d 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1301,12 +1301,12 @@ machine_check_handle_early:
 	lbz	r3,PACA_THREAD_IDLE_STATE(r13)
 	cmpwi	r3,PNV_THREAD_NAP
 	bgt	10f
-	IDLE_STATE_ENTER_SEQ(PPC_NAP)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_NAP)
 	/* No return */
 10:
 	cmpwi	r3,PNV_THREAD_SLEEP
 	bgt	2f
-	IDLE_STATE_ENTER_SEQ(PPC_SLEEP)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_SLEEP)
 	/* No return */
 
 2:
@@ -1320,7 +1320,7 @@ machine_check_handle_early:
 	 */
 	ori	r13,r13,1
 	SET_PACA(r13)
-	IDLE_STATE_ENTER_SEQ(PPC_WINKLE)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_WINKLE)
 	/* No return */
 4:
 #endif
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 72dac0b..be90e2f 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -205,7 +205,7 @@ pnv_enter_arch207_idle_mode:
 	stb	r3,PACA_THREAD_IDLE_STATE(r13)
 	cmpwi	cr3,r3,PNV_THREAD_SLEEP
 	bge	cr3,2f
-	IDLE_STATE_ENTER_SEQ(PPC_NAP)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_NAP)
 	/* No return */
 2:
 	/* Sleep or winkle */
@@ -239,7 +239,7 @@ pnv_fastsleep_workaround_at_entry:
 
 common_enter: /* common code for all the threads entering sleep or winkle */
 	bgt	cr3,enter_winkle
-	IDLE_STATE_ENTER_SEQ(PPC_SLEEP)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_SLEEP)
 
 fastsleep_workaround_at_entry:
 	ori	r15,r15,PNV_CORE_IDLE_LOCK_BIT
@@ -261,7 +261,7 @@ fastsleep_workaround_at_entry:
 enter_winkle:
 	bl	save_sprs_to_stack
 
-	IDLE_STATE_ENTER_SEQ(PPC_WINKLE)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_WINKLE)
 
 /*
  * r3 - requested stop state
@@ -280,7 +280,7 @@ power_enter_stop:
 	ld	r4,ADDROFF(pnv_first_deep_stop_state)(r5)
 	cmpd	r3,r4
 	bge	2f
-	IDLE_STATE_ENTER_SEQ(PPC_STOP)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
 2:
 /*
  * Entering deep idle state.
@@ -302,7 +302,7 @@ lwarx_loop_stop:
 
 	bl	save_sprs_to_stack
 
-	IDLE_STATE_ENTER_SEQ(PPC_STOP)
+	IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
 
 _GLOBAL(power7_idle)
 	/* Now check if user or arch enabled NAP mode */
-- 
2.7.4