[PATCH v4 1/4] powernv:idle: Add IDLE_STATE_ENTER_SEQ_NORET macro

From: Gautham R. Shenoy
Date: Fri Dec 09 2016 - 08:32:46 EST


From: "Gautham R. Shenoy" <ego@xxxxxxxxxxxxxxxxxx>

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_300, 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.

Signed-off-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/cpuidle.h | 5 ++++-
arch/powerpc/kernel/exceptions-64s.S | 6 +++---
arch/powerpc/kernel/idle_book3s.S | 10 +++++-----
3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h
index 3919332..0a3255b 100644
--- a/arch/powerpc/include/asm/cpuidle.h
+++ b/arch/powerpc/include/asm/cpuidle.h
@@ -21,7 +21,7 @@

/* Idle state entry routines */
#ifdef CONFIG_PPC_P7_NAP
-#define IDLE_STATE_ENTER_SEQ(IDLE_INST) \
+#define IDLE_STATE_ENTER_SEQ(IDLE_INST) \
/* Magic NAP/SLEEP/WINKLE mode enter sequence */ \
std r0,0(r1); \
ptesync; \
@@ -29,6 +29,9 @@
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 1ba82ea..7aa8afc 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -381,12 +381,12 @@ EXC_COMMON_BEGIN(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:
@@ -400,7 +400,7 @@ EXC_COMMON_BEGIN(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 */
--
1.9.4