Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752756Ab3DKTiz (ORCPT ); Thu, 11 Apr 2013 15:38:55 -0400 Received: from smtp.snhosting.dk ([87.238.248.203]:18218 "EHLO smtp.domainteam.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750792Ab3DKTiw (ORCPT ); Thu, 11 Apr 2013 15:38:52 -0400 Date: Thu, 11 Apr 2013 21:38:50 +0200 From: Sam Ravnborg To: David Miller , Thomas Gleixner Cc: srivatsa.bhat@linux.vnet.ibm.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, rusty@rustcorp.com.au, paulmck@linux.vnet.ibm.com, mingo@elte.hu, peterz@infradead.org, magnus.damm@gmail.com Subject: [PATCH v2] sparc: Use generic idle loop Message-ID: <20130411193850.GA2330@merkur.ravnborg.org> References: <20130401090620.GA24861@merkur.ravnborg.org> <5162B92E.6020703@linux.vnet.ibm.com> <20130408171035.GA27264@merkur.ravnborg.org> <20130408.152449.169732563685022388.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130408.152449.169732563685022388.davem@davemloft.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5665 Lines: 213 Add generic cpu_idle support sparc32: - replace call to cpu_idle() with cpu_startup_entry() - add arch_cpu_idle() sparc64: - smp_callin() now include cpu_startup_entry() call so we can skip calling cpu_idle from assembler - add arch_cpu_idle() and arch_cpu_idle_dead() Signed-off-by: Sam Ravnborg Reviewed-by: "Srivatsa S. Bhat" Cc: David S. Miller --- v1->v2: - simplified arch_cpu_idle() - former sparc64_yield() based on comments from Srivatsa - dropped TIF_POLLING_NRFLAG handling - dropped smp_mb__after_clear_bit() - this is done in generic code using rmb() - dropped the out-most while (!need_resched() && !cpu_is_offline(cpu)) - always enable irq on exit in arch_cpu_idle (both sparc32 and sparc64) - added comment from davem why we need to clear IE bit in sparc64 arch_cpu_idle() Sam diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 3d361f2..ee5eacc 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -37,6 +37,7 @@ config SPARC select GENERIC_SMP_IDLE_THREAD select GENERIC_CMOS_UPDATE select GENERIC_CLOCKEVENTS + select GENERIC_IDLE_LOOP select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select MODULES_USE_ELF_RELA diff --git a/arch/sparc/kernel/hvtramp.S b/arch/sparc/kernel/hvtramp.S index 9365432..605c960 100644 --- a/arch/sparc/kernel/hvtramp.S +++ b/arch/sparc/kernel/hvtramp.S @@ -128,8 +128,7 @@ hv_cpu_startup: call smp_callin nop - call cpu_idle - mov 0, %o0 + call cpu_panic nop diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c index 62eede1..c852410 100644 --- a/arch/sparc/kernel/process_32.c +++ b/arch/sparc/kernel/process_32.c @@ -64,23 +64,12 @@ extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *); struct task_struct *last_task_used_math = NULL; struct thread_info *current_set[NR_CPUS]; -/* - * the idle loop on a Sparc... ;) - */ -void cpu_idle(void) +/* Idle loop support. */ +void arch_cpu_idle(void) { - set_thread_flag(TIF_POLLING_NRFLAG); - - /* endless idle loop with no priority at all */ - for (;;) { - while (!need_resched()) { - if (sparc_idle) - (*sparc_idle)(); - else - cpu_relax(); - } - schedule_preempt_disabled(); - } + if (sparc_idle) + (*sparc_idle)(); + local_irq_enable(); } /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */ diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c index cdb80b2..9fbf0d1 100644 --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -52,20 +52,17 @@ #include "kstack.h" -static void sparc64_yield(int cpu) +/* Idle loop support on sparc64. */ +void arch_cpu_idle(void) { if (tlb_type != hypervisor) { touch_nmi_watchdog(); - return; - } - - clear_thread_flag(TIF_POLLING_NRFLAG); - smp_mb__after_clear_bit(); - - while (!need_resched() && !cpu_is_offline(cpu)) { + } else { unsigned long pstate; - /* Disable interrupts. */ + /* The sun4v sleeping code requires that we have PSTATE.IE cleared over + * the cpu sleep hypervisor call. + */ __asm__ __volatile__( "rdpr %%pstate, %0\n\t" "andn %0, %1, %0\n\t" @@ -73,7 +70,7 @@ static void sparc64_yield(int cpu) : "=&r" (pstate) : "i" (PSTATE_IE)); - if (!need_resched() && !cpu_is_offline(cpu)) + if (!need_resched() && !cpu_is_offline(smp_processor_id())) sun4v_cpu_yield(); /* Re-enable interrupts. */ @@ -84,36 +81,16 @@ static void sparc64_yield(int cpu) : "=&r" (pstate) : "i" (PSTATE_IE)); } - - set_thread_flag(TIF_POLLING_NRFLAG); + local_irq_enable(); } -/* The idle loop on sparc64. */ -void cpu_idle(void) -{ - int cpu = smp_processor_id(); - - set_thread_flag(TIF_POLLING_NRFLAG); - - while(1) { - tick_nohz_idle_enter(); - rcu_idle_enter(); - - while (!need_resched() && !cpu_is_offline(cpu)) - sparc64_yield(cpu); - - rcu_idle_exit(); - tick_nohz_idle_exit(); - #ifdef CONFIG_HOTPLUG_CPU - if (cpu_is_offline(cpu)) { - sched_preempt_enable_no_resched(); - cpu_play_dead(); - } -#endif - schedule_preempt_disabled(); - } +void arch_cpu_idle_dead() +{ + sched_preempt_enable_no_resched(); + cpu_play_dead(); } +#endif #ifdef CONFIG_COMPAT static void show_regwindow32(struct pt_regs *regs) diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c index 9e7e6d7..e3f2b81 100644 --- a/arch/sparc/kernel/smp_32.c +++ b/arch/sparc/kernel/smp_32.c @@ -369,7 +369,7 @@ void __cpuinit sparc_start_secondary(void *arg) local_irq_enable(); wmb(); - cpu_idle(); + cpu_startup_entry(CPUHP_ONLINE); /* We should never reach here! */ BUG(); diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index 537eb66..c025ffc 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -127,6 +127,8 @@ void __cpuinit smp_callin(void) /* idle thread is expected to have preempt disabled */ preempt_disable(); + + cpu_startup_entry(CPUHP_ONLINE); } void cpu_panic(void) diff --git a/arch/sparc/kernel/trampoline_64.S b/arch/sparc/kernel/trampoline_64.S index da1b781..2e973a2 100644 --- a/arch/sparc/kernel/trampoline_64.S +++ b/arch/sparc/kernel/trampoline_64.S @@ -407,8 +407,7 @@ after_lock_tlb: call smp_callin nop - call cpu_idle - mov 0, %o0 + call cpu_panic nop 1: b,a,pt %xcc, 1b -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/