From: Gautham R Shenoy <ego@linux•vnet.ibm.com>
To: Nicholas Piggin <npiggin@gmail•com>
Cc: linuxppc-dev@lists•ozlabs.org,
Gautham R Shenoy <ego@linux•vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux•vnet.ibm.com>
Subject: Re: [PATCH 6/8] powerpc/64s: idle expand usable core idle state bits
Date: Thu, 16 Mar 2017 17:40:51 +0530 [thread overview]
Message-ID: <20170316121051.GD16462@in.ibm.com> (raw)
In-Reply-To: <20170314092349.10981-7-npiggin@gmail.com>
Hi Nick,
On Tue, Mar 14, 2017 at 07:23:47PM +1000, Nicholas Piggin wrote:
> In preparation for adding more bits to the core idle state word,
> move the lock bit up, and unlock by flipping the lock bit rather
> than masking off all but the thread bits.
>
> Add branch hints for atomic operations while we're here.
Looks good.
Reviewed-by: Gautham R. Shenoy <ego@linux•vnet.ibm.com>
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
> ---
> arch/powerpc/include/asm/cpuidle.h | 4 ++--
> arch/powerpc/kernel/idle_book3s.S | 33 +++++++++++++++++----------------
> 2 files changed, 19 insertions(+), 18 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h
> index 155731557c9b..b9d9f960dffd 100644
> --- a/arch/powerpc/include/asm/cpuidle.h
> +++ b/arch/powerpc/include/asm/cpuidle.h
> @@ -7,8 +7,8 @@
> #define PNV_THREAD_NAP 1
> #define PNV_THREAD_SLEEP 2
> #define PNV_THREAD_WINKLE 3
> -#define PNV_CORE_IDLE_LOCK_BIT 0x100
> -#define PNV_CORE_IDLE_THREAD_BITS 0x0FF
> +#define PNV_CORE_IDLE_LOCK_BIT 0x10000000
> +#define PNV_CORE_IDLE_THREAD_BITS 0x000000FF
>
> /*
> * ============================ NOTE =================================
> diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
> index 9bdfba75a5e7..1c91dc35c559 100644
> --- a/arch/powerpc/kernel/idle_book3s.S
> +++ b/arch/powerpc/kernel/idle_book3s.S
> @@ -95,12 +95,12 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
> core_idle_lock_held:
> HMT_LOW
> 3: lwz r15,0(r14)
> - andi. r15,r15,PNV_CORE_IDLE_LOCK_BIT
> + andis. r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
> bne 3b
> HMT_MEDIUM
> lwarx r15,0,r14
> - andi. r9,r15,PNV_CORE_IDLE_LOCK_BIT
> - bne core_idle_lock_held
> + andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
> + bne- core_idle_lock_held
> blr
>
> /*
> @@ -213,8 +213,8 @@ pnv_enter_arch207_idle_mode:
> lwarx_loop1:
> lwarx r15,0,r14
>
> - andi. r9,r15,PNV_CORE_IDLE_LOCK_BIT
> - bnel core_idle_lock_held
> + andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
> + bnel- core_idle_lock_held
>
> andc r15,r15,r7 /* Clear thread bit */
>
> @@ -241,7 +241,7 @@ common_enter: /* common code for all the threads entering sleep or winkle */
> IDLE_STATE_ENTER_SEQ_NORET(PPC_SLEEP)
>
> fastsleep_workaround_at_entry:
> - ori r15,r15,PNV_CORE_IDLE_LOCK_BIT
> + oris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
> stwcx. r15,0,r14
> bne- lwarx_loop1
> isync
> @@ -251,10 +251,10 @@ fastsleep_workaround_at_entry:
> li r4,1
> bl opal_config_cpu_idle_state
>
> - /* Clear Lock bit */
> - li r0,0
> + /* Unlock */
> + xoris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
> lwsync
> - stw r0,0(r14)
> + stw r15,0(r14)
> b common_enter
>
> enter_winkle:
> @@ -302,8 +302,8 @@ power_enter_stop:
>
> lwarx_loop_stop:
> lwarx r15,0,r14
> - andi. r9,r15,PNV_CORE_IDLE_LOCK_BIT
> - bnel core_idle_lock_held
> + andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
> + bnel- core_idle_lock_held
> andc r15,r15,r7 /* Clear thread bit */
>
> stwcx. r15,0,r14
> @@ -492,7 +492,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
> ld r14,PACA_CORE_IDLE_STATE_PTR(r13)
> lwarx_loop2:
> lwarx r15,0,r14
> - andi. r9,r15,PNV_CORE_IDLE_LOCK_BIT
> + andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
> /*
> * Lock bit is set in one of the 2 cases-
> * a. In the sleep/winkle enter path, the last thread is executing
> @@ -501,9 +501,10 @@ lwarx_loop2:
> * workaround undo code or resyncing timebase or restoring context
> * In either case loop until the lock bit is cleared.
> */
> - bnel core_idle_lock_held
> + bnel- core_idle_lock_held
>
> - cmpwi cr2,r15,0
> + andi. r9,r15,PNV_CORE_IDLE_THREAD_BITS
> + cmpwi cr2,r9,0
>
> /*
> * At this stage
> @@ -512,7 +513,7 @@ lwarx_loop2:
> * cr4 - gt or eq if waking up from complete hypervisor state loss.
> */
>
> - ori r15,r15,PNV_CORE_IDLE_LOCK_BIT
> + oris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
> stwcx. r15,0,r14
> bne- lwarx_loop2
> isync
> @@ -602,7 +603,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
> mtspr SPRN_WORC,r4
>
> clear_lock:
> - andi. r15,r15,PNV_CORE_IDLE_THREAD_BITS
> + xoris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
> lwsync
> stw r15,0(r14)
>
> --
> 2.11.0
>
next prev parent reply other threads:[~2017-03-16 12:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-14 9:23 [PATCH 0/8] idle fixes and changes for POWER8 and POWER9 Nicholas Piggin
2017-03-14 9:23 ` [PATCH 1/8] powerpc/64s: move remaining system reset idle code into idle_book3s.S Nicholas Piggin
2017-03-14 9:23 ` [PATCH 2/8] powerpc/64s: stop using bit in HSPRG0 to test winkle Nicholas Piggin
2017-03-16 11:14 ` Gautham R Shenoy
2017-03-14 9:23 ` [PATCH 3/8] powerpc/64s: use alternative feature patching Nicholas Piggin
2017-03-16 11:21 ` Gautham R Shenoy
2017-03-14 9:23 ` [PATCH 4/8] powerpc/64s: fix POWER9 machine check handler from stop state Nicholas Piggin
2017-03-16 12:40 ` Mahesh Jagannath Salgaonkar
2017-03-16 13:05 ` Nicholas Piggin
2017-03-16 13:19 ` Gautham R Shenoy
2017-03-20 5:22 ` Mahesh Jagannath Salgaonkar
2017-03-17 2:49 ` Nicholas Piggin
2017-03-17 5:15 ` Nicholas Piggin
2017-03-14 9:23 ` [PATCH 5/8] powerpc/64s: use PACA_THREAD_IDLE_STATE only in POWER8 Nicholas Piggin
2017-03-16 11:54 ` Gautham R Shenoy
2017-03-16 12:16 ` Nicholas Piggin
2017-03-14 9:23 ` [PATCH 6/8] powerpc/64s: idle expand usable core idle state bits Nicholas Piggin
2017-03-16 12:10 ` Gautham R Shenoy [this message]
2017-03-14 9:23 ` [PATCH 7/8] powerpc/64s: idle do not hold reservation longer than required Nicholas Piggin
2017-03-16 12:43 ` Gautham R Shenoy
2017-03-16 12:55 ` Nicholas Piggin
2017-03-14 9:23 ` [PATCH 8/8] powerpc/64s: idle POWER8 avoid full state loss recovery when possible Nicholas Piggin
2017-03-16 16:12 ` Gautham R Shenoy
2017-03-17 5:24 ` Nicholas Piggin
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