From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-x241.google.com (mail-it0-x241.google.com [IPv6:2607:f8b0:4001:c0b::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wfGMy4bBQzDqL4 for ; Fri, 2 Jun 2017 17:40:30 +1000 (AEST) Received: by mail-it0-x241.google.com with SMTP id 67so8871665itx.2 for ; Fri, 02 Jun 2017 00:40:30 -0700 (PDT) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , Anton Blanchard Subject: [PATCH 10/14] powerpc/64: CTRL[RUN] run-latch setting optimisation Date: Fri, 2 Jun 2017 17:39:42 +1000 Message-Id: <20170602073946.8983-11-npiggin@gmail.com> In-Reply-To: <20170602073946.8983-1-npiggin@gmail.com> References: <20170602073946.8983-1-npiggin@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The CTRL register is read-only except bit 63 which is the run latch control. This means it can be updated with a mtspr rather than mfspr/mtspr. Signed-off-by: Nicholas Piggin --- arch/powerpc/kernel/process.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 5cbb8b1faf7e..633ec9967141 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1964,12 +1964,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) void notrace __ppc64_runlatch_on(void) { struct thread_info *ti = current_thread_info(); - unsigned long ctrl; - - ctrl = mfspr(SPRN_CTRLF); - ctrl |= CTRL_RUNLATCH; - mtspr(SPRN_CTRLT, ctrl); + mtspr(SPRN_CTRLT, CTRL_RUNLATCH); ti->local_flags |= _TLF_RUNLATCH; } @@ -1977,13 +1973,9 @@ void notrace __ppc64_runlatch_on(void) void notrace __ppc64_runlatch_off(void) { struct thread_info *ti = current_thread_info(); - unsigned long ctrl; ti->local_flags &= ~_TLF_RUNLATCH; - - ctrl = mfspr(SPRN_CTRLF); - ctrl &= ~CTRL_RUNLATCH; - mtspr(SPRN_CTRLT, ctrl); + mtspr(SPRN_CTRLT, 0); } #endif /* CONFIG_PPC64 */ -- 2.11.0