From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEAC8C433EB for ; Mon, 29 Mar 2021 08:35:50 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EA73861613 for ; Mon, 29 Mar 2021 08:35:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA73861613 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4F85WS1K4tz30BB for ; Mon, 29 Mar 2021 19:35:48 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=benh@kernel.crashing.org; receiver=) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 4F85W46Mlgz2yxF for ; Mon, 29 Mar 2021 19:35:27 +1100 (AEDT) Received: from ip6-localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 12T8XKM1023340; Mon, 29 Mar 2021 03:33:21 -0500 Message-ID: Subject: Re: [PATCH] powerpc/64s: power4 nap fixup in C From: Benjamin Herrenschmidt To: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org Date: Mon, 29 Mar 2021 19:33:20 +1100 In-Reply-To: <20210312012044.3660743-1-npiggin@gmail.com> References: <20210312012044.3660743-1-npiggin@gmail.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.4-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, 2021-03-12 at 11:20 +1000, Nicholas Piggin wrote: > > +static inline void nap_adjust_return(struct pt_regs *regs) > > +{ > > +#ifdef CONFIG_PPC_970_NAP > > + if (unlikely(test_thread_local_flags(_TLF_NAPPING))) { > + /* Can avoid a test-and-clear because NMIs do not call this */ > + clear_thread_local_flags(_TLF_NAPPING); > + regs->nip = (unsigned long)power4_idle_nap_return; > + } Is this a pointer to a function descriptor or the actual code ? Cheers, Ben. > +#endif > > +} > > + > > struct interrupt_state { > > #ifdef CONFIG_PPC_BOOK3E_64 > > enum ctx_state ctx_state; > > @@ -111,6 +122,9 @@ static inline void interrupt_async_exit_prepare(struct pt_regs *regs, struct int > > { > > irq_exit(); > > interrupt_exit_prepare(regs, state); > > + > > + /* Adjust at exit so the main handler sees the true NIA */ > > + nap_adjust_return(regs); > > } > > > > struct interrupt_nmi_state { > > @@ -164,6 +178,11 @@ static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct inter > > radix_enabled() || (mfmsr() & MSR_DR)) > > nmi_exit(); > > > > + /* > > + * nmi does not call nap_adjust_return because nmi should not create > > + * new work to do (must use irq_work for that). > > + */ > > + > > #ifdef CONFIG_PPC64 > > if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260) > > this_cpu_set_ftrace_enabled(state->ftrace_enabled); > > diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h > > index 8acc3590c971..eedc3c775141 100644 > > --- a/arch/powerpc/include/asm/processor.h > > +++ b/arch/powerpc/include/asm/processor.h > > @@ -393,6 +393,7 @@ extern unsigned long isa300_idle_stop_mayloss(unsigned long psscr_val); > > extern unsigned long isa206_idle_insn_mayloss(unsigned long type); > > #ifdef CONFIG_PPC_970_NAP > > extern void power4_idle_nap(void); > > +void power4_idle_nap_return(void); > > #endif > > > > extern unsigned long cpuidle_disable; > > diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h > > index 386d576673a1..bf137151100b 100644 > > --- a/arch/powerpc/include/asm/thread_info.h > > +++ b/arch/powerpc/include/asm/thread_info.h > > @@ -152,6 +152,12 @@ void arch_setup_new_exec(void); > > > > #ifndef __ASSEMBLY__ > > > > +static inline void clear_thread_local_flags(unsigned int flags) > > +{ > > + struct thread_info *ti = current_thread_info(); > > + ti->local_flags &= ~flags; > > +} > > + > > static inline bool test_thread_local_flags(unsigned int flags) > > { > > struct thread_info *ti = current_thread_info(); > > diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S > > index 60d3051a8bc8..ea7a443488d2 100644 > > --- a/arch/powerpc/kernel/exceptions-64s.S > > +++ b/arch/powerpc/kernel/exceptions-64s.S > > @@ -692,25 +692,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR) > > ld r1,GPR1(r1) > > .endm > > > > -/* > > - * When the idle code in power4_idle puts the CPU into NAP mode, > > - * it has to do so in a loop, and relies on the external interrupt > > - * and decrementer interrupt entry code to get it out of the loop. > > - * It sets the _TLF_NAPPING bit in current_thread_info()->local_flags > > - * to signal that it is in the loop and needs help to get out. > > - */ > > -#ifdef CONFIG_PPC_970_NAP > > -#define FINISH_NAP \ > > -BEGIN_FTR_SECTION \ > > - ld r11, PACA_THREAD_INFO(r13); \ > > - ld r9,TI_LOCAL_FLAGS(r11); \ > > - andi. r10,r9,_TLF_NAPPING; \ > > - bnel power4_fixup_nap; \ > > -END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) > > -#else > > -#define FINISH_NAP > > -#endif > > - > > /* > > * There are a few constraints to be concerned with. > > * - Real mode exceptions code/data must be located at their physical location. > > @@ -1248,7 +1229,6 @@ EXC_COMMON_BEGIN(machine_check_common) > > */ > > GEN_COMMON machine_check > > > > - FINISH_NAP > > /* Enable MSR_RI when finished with PACA_EXMC */ > > li r10,MSR_RI > > mtmsrd r10,1 > > @@ -1571,7 +1551,6 @@ EXC_VIRT_BEGIN(hardware_interrupt, 0x4500, 0x100) > > EXC_VIRT_END(hardware_interrupt, 0x4500, 0x100) > > EXC_COMMON_BEGIN(hardware_interrupt_common) > > GEN_COMMON hardware_interrupt > > - FINISH_NAP > > addi r3,r1,STACK_FRAME_OVERHEAD > > bl do_IRQ > > b interrupt_return > > @@ -1801,7 +1780,6 @@ EXC_VIRT_BEGIN(decrementer, 0x4900, 0x80) > > EXC_VIRT_END(decrementer, 0x4900, 0x80) > > EXC_COMMON_BEGIN(decrementer_common) > > GEN_COMMON decrementer > > - FINISH_NAP > > addi r3,r1,STACK_FRAME_OVERHEAD > > bl timer_interrupt > > b interrupt_return > > @@ -1886,7 +1864,6 @@ EXC_VIRT_BEGIN(doorbell_super, 0x4a00, 0x100) > > EXC_VIRT_END(doorbell_super, 0x4a00, 0x100) > > EXC_COMMON_BEGIN(doorbell_super_common) > > GEN_COMMON doorbell_super > > - FINISH_NAP > > addi r3,r1,STACK_FRAME_OVERHEAD > > #ifdef CONFIG_PPC_DOORBELL > > bl doorbell_exception > > @@ -2237,7 +2214,6 @@ EXC_COMMON_BEGIN(hmi_exception_early_common) > > > > EXC_COMMON_BEGIN(hmi_exception_common) > > GEN_COMMON hmi_exception > > - FINISH_NAP > > addi r3,r1,STACK_FRAME_OVERHEAD > > bl handle_hmi_exception > > b interrupt_return > > @@ -2266,7 +2242,6 @@ EXC_VIRT_BEGIN(h_doorbell, 0x4e80, 0x20) > > EXC_VIRT_END(h_doorbell, 0x4e80, 0x20) > > EXC_COMMON_BEGIN(h_doorbell_common) > > GEN_COMMON h_doorbell > > - FINISH_NAP > > addi r3,r1,STACK_FRAME_OVERHEAD > > #ifdef CONFIG_PPC_DOORBELL > > bl doorbell_exception > > @@ -2299,7 +2274,6 @@ EXC_VIRT_BEGIN(h_virt_irq, 0x4ea0, 0x20) > > EXC_VIRT_END(h_virt_irq, 0x4ea0, 0x20) > > EXC_COMMON_BEGIN(h_virt_irq_common) > > GEN_COMMON h_virt_irq > > - FINISH_NAP > > addi r3,r1,STACK_FRAME_OVERHEAD > > bl do_IRQ > > b interrupt_return > > @@ -2345,7 +2319,6 @@ EXC_VIRT_BEGIN(performance_monitor, 0x4f00, 0x20) > > EXC_VIRT_END(performance_monitor, 0x4f00, 0x20) > > EXC_COMMON_BEGIN(performance_monitor_common) > > GEN_COMMON performance_monitor > > - FINISH_NAP > > addi r3,r1,STACK_FRAME_OVERHEAD > > bl performance_monitor_exception > > b interrupt_return > > @@ -3096,24 +3069,6 @@ USE_FIXED_SECTION(virt_trampolines) > > __end_interrupts: > > DEFINE_FIXED_SYMBOL(__end_interrupts) > > > > -#ifdef CONFIG_PPC_970_NAP > > - /* > > - * Called by exception entry code if _TLF_NAPPING was set, this clears > > - * the NAPPING flag, and redirects the exception exit to > > - * power4_fixup_nap_return. > > - */ > > - .globl power4_fixup_nap > > -EXC_COMMON_BEGIN(power4_fixup_nap) > > - andc r9,r9,r10 > > - std r9,TI_LOCAL_FLAGS(r11) > > - LOAD_REG_ADDR(r10, power4_idle_nap_return) > > - std r10,_NIP(r1) > > - blr > > - > > -power4_idle_nap_return: > > - blr > > -#endif > > - > > CLOSE_FIXED_SECTION(real_vectors); > > CLOSE_FIXED_SECTION(real_trampolines); > > CLOSE_FIXED_SECTION(virt_vectors); > > diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S > > index f9e6d83e6720..abb719b21cae 100644 > > --- a/arch/powerpc/kernel/idle_book3s.S > > +++ b/arch/powerpc/kernel/idle_book3s.S > > @@ -209,4 +209,8 @@ _GLOBAL(power4_idle_nap) > > mtmsrd r7 > > isync > > b 1b > > + > > + .globl power4_idle_nap_return > > +power4_idle_nap_return: > > + blr > > #endif > > -- > > 2.23.0