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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 169A9C433B4 for ; Mon, 10 May 2021 16:33:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E722F61165 for ; Mon, 10 May 2021 16:33:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231408AbhEJQed (ORCPT ); Mon, 10 May 2021 12:34:33 -0400 Received: from mga17.intel.com ([192.55.52.151]:22044 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231671AbhEJQeG (ORCPT ); Mon, 10 May 2021 12:34:06 -0400 IronPort-SDR: ZnYLuHk5D+1DhW63U9iEmpvfd7rv8TIGXzSjwkY1ZMz/EY9lItS7Nhz6B5GrIS+hse0NXtBkDK 5csFtE7p1/Bw== X-IronPort-AV: E=McAfee;i="6200,9189,9980"; a="179498656" X-IronPort-AV: E=Sophos;i="5.82,287,1613462400"; d="scan'208";a="179498656" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2021 09:32:59 -0700 IronPort-SDR: 3cxA7V6Is8mgi+6NpnbCZh4F/Q2k5mVED0Tzo5ioPlnB097C3dRaFMFhMjxe6TXffltgAUZ7YD nmy1vjOB5aWA== X-IronPort-AV: E=Sophos;i="5.82,287,1613462400"; d="scan'208";a="391973628" Received: from kmlaurix-mobl3.amr.corp.intel.com (HELO skuppusw-mobl5.amr.corp.intel.com) ([10.212.3.156]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2021 09:32:58 -0700 Subject: Re: [PATCH v3 3/3] x86/acpi, x86/boot: Add multiprocessor wake-up support To: Rafael J Wysocki , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra Cc: Len Brown , Robert Moore , Erik Kaneda , linux-acpi@vger.kernel.org, devel@acpica.org, linux-kernel@vger.kernel.org, x86@kernel.org, Sean Christopherson , Andi Kleen References: <20210426023941.729334-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20210426023941.729334-4-sathyanarayanan.kuppuswamy@linux.intel.com> From: "Kuppuswamy, Sathyanarayanan" Message-ID: <97e14cdc-ea98-18b8-0c89-db52440a7716@linux.intel.com> Date: Mon, 10 May 2021 09:32:55 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210426023941.729334-4-sathyanarayanan.kuppuswamy@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi Rafael/Thomas, On 4/25/21 7:39 PM, Kuppuswamy Sathyanarayanan wrote: > As per ACPI specification r6.4, sec 5.2.12.19, a new sub > structure – multiprocessor wake-up structure - is added to the > ACPI Multiple APIC Description Table (MADT) to describe the > information of the mailbox. If a platform firmware produces the > multiprocessor wake-up structure, then OS may use this new > mailbox-based mechanism to wake up the APs. > > Add ACPI MADT wake table parsing support for x86 platform and if > MADT wake table is present, update apic->wakeup_secondary_cpu with > new API which uses MADT wake mailbox to wake-up CPU. Gentle ping. Any comments on this patch? I think I have addressed the concerns raised by you in previous version. > > Co-developed-by: Sean Christopherson > Signed-off-by: Sean Christopherson > Signed-off-by: Kuppuswamy Sathyanarayanan > Reviewed-by: Andi Kleen > --- > arch/x86/include/asm/apic.h | 3 ++ > arch/x86/kernel/acpi/boot.c | 79 +++++++++++++++++++++++++++++++++++++ > arch/x86/kernel/apic/apic.c | 8 ++++ > 3 files changed, 90 insertions(+) > > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h > index 412b51e059c8..3e94e1f402ea 100644 > --- a/arch/x86/include/asm/apic.h > +++ b/arch/x86/include/asm/apic.h > @@ -487,6 +487,9 @@ static inline unsigned int read_apic_id(void) > return apic->get_apic_id(reg); > } > > +typedef int (*wakeup_cpu_handler)(int apicid, unsigned long start_eip); > +extern void acpi_wake_cpu_handler_update(wakeup_cpu_handler handler); > + > extern int default_apic_id_valid(u32 apicid); > extern int default_acpi_madt_oem_check(char *, char *); > extern void default_setup_apic_routing(void); > diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c > index 14cd3186dc77..fce2aa7d718f 100644 > --- a/arch/x86/kernel/acpi/boot.c > +++ b/arch/x86/kernel/acpi/boot.c > @@ -65,6 +65,9 @@ int acpi_fix_pin2_polarity __initdata; > static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; > #endif > > +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox; > +static u64 acpi_mp_wake_mailbox_paddr; > + > #ifdef CONFIG_X86_IO_APIC > /* > * Locks related to IOAPIC hotplug > @@ -329,6 +332,52 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e > return 0; > } > > +static void acpi_mp_wake_mailbox_init(void) > +{ > + if (acpi_mp_wake_mailbox) > + return; > + > + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr, > + sizeof(*acpi_mp_wake_mailbox), MEMREMAP_WB); > +} > + > +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip) > +{ > + u8 timeout = 0xFF; > + > + acpi_mp_wake_mailbox_init(); > + > + if (!acpi_mp_wake_mailbox) > + return -EINVAL; > + > + /* > + * Mailbox memory is shared between firmware and OS. Firmware will > + * listen on mailbox command address, and once it receives the wakeup > + * command, CPU associated with the given apicid will be booted. So, > + * the value of apic_id and wakeup_vector has to be set before updating > + * the wakeup command. So use WRITE_ONCE to let the compiler know about > + * it and preserve the order of writes. > + */ > + WRITE_ONCE(acpi_mp_wake_mailbox->apic_id, apicid); > + WRITE_ONCE(acpi_mp_wake_mailbox->wakeup_vector, start_ip); > + WRITE_ONCE(acpi_mp_wake_mailbox->command, ACPI_MP_WAKE_COMMAND_WAKEUP); > + > + /* > + * After writing wakeup command, wait for maximum timeout of 0xFF > + * for firmware to reset the command address back zero to indicate > + * the successful reception of command. > + * NOTE: 255 as timeout value is decided based on our experiments. > + * > + * XXX: Change the timeout once ACPI specification comes up with > + * standard maximum timeout value. > + */ > + while (READ_ONCE(acpi_mp_wake_mailbox->command) && timeout--) > + cpu_relax(); > + > + /* If timedout, return error */ > + return timeout ? 0 : -EIO; > +} > + > #endif /*CONFIG_X86_LOCAL_APIC */ > > #ifdef CONFIG_X86_IO_APIC > @@ -1086,6 +1135,30 @@ static int __init acpi_parse_madt_lapic_entries(void) > } > return 0; > } > + > +static int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, > + const unsigned long end) > +{ > + struct acpi_madt_multiproc_wakeup *mp_wake; > + > + if (acpi_mp_wake_mailbox) > + return -EINVAL; > + > + if (!IS_ENABLED(CONFIG_SMP)) > + return -ENODEV; > + > + mp_wake = (struct acpi_madt_multiproc_wakeup *) header; > + if (BAD_MADT_ENTRY(mp_wake, end)) > + return -EINVAL; > + > + acpi_table_print_madt_entry(&header->common); > + > + acpi_mp_wake_mailbox_paddr = mp_wake->base_address; > + > + acpi_wake_cpu_handler_update(acpi_wakeup_cpu); > + > + return 0; > +} > #endif /* CONFIG_X86_LOCAL_APIC */ > > #ifdef CONFIG_X86_IO_APIC > @@ -1284,6 +1357,12 @@ static void __init acpi_process_madt(void) > > smp_found_config = 1; > } > + > + /* > + * Parse MADT MP Wake entry. > + */ > + acpi_table_parse_madt(ACPI_MADT_TYPE_MULTIPROC_WAKEUP, > + acpi_parse_mp_wake, 1); > } > if (error == -EINVAL) { > /* > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index 4f26700f314d..f1b90a4b89e8 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -2554,6 +2554,14 @@ u32 x86_msi_msg_get_destid(struct msi_msg *msg, bool extid) > } > EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid); > > +void __init acpi_wake_cpu_handler_update(wakeup_cpu_handler handler) > +{ > + struct apic **drv; > + > + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) > + (*drv)->wakeup_secondary_cpu = handler; > +} > + > /* > * Override the generic EOI implementation with an optimized version. > * Only called during early boot when only one CPU is active and with > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer