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Subject[PATCH v5 1/5] powernv:idle: Add IDLE_STATE_ENTER_SEQ_NORET macro
Date
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>

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.

Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
---
No changes from v4

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
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