From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752493AbeAQJay (ORCPT + 1 other); Wed, 17 Jan 2018 04:30:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53126 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750908AbeAQJav (ORCPT ); Wed, 17 Jan 2018 04:30:51 -0500 Date: Wed, 17 Jan 2018 17:30:39 +0800 From: Baoquan He To: linux-kernel@vger.kernel.org, ebiederm@xmission.com Cc: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, x86@kernel.org, douly.fnst@cn.fujitsu.com, rostedt@goodmis.org, jgross@suse.com, peterz@infradead.org, uobergfe@redhat.com, joro@8bytes.org Subject: Re: [RESEND PATCH 2/3] x86/apic/kexec: Enable legacy irq mode before jump to kexec/kdump kernel Message-ID: <20180117093039.GC2321@localhost.localdomain> References: <1515123732-28908-1-git-send-email-bhe@redhat.com> <20180105043838.GK7235@x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180105043838.GK7235@x1> User-Agent: Mutt/1.9.1 (2017-09-22) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 17 Jan 2018 09:30:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: CC Eric On 01/05/18 at 12:38pm, Baoquan He wrote: > In commit > > commit 522e66464467 ("x86/apic: Disable I/O APIC before shutdown of the local APIC"). > > lapic_shutdown() invocation is moved after disable_IO_APIC(). In fact > in disable_IO_APIC(), it not only calls clear_IO_APIC() to disable > IO-APIC, also sets sets LAPIC and IO-APIC to make system be PIC or > Virtual wire mode. While the above commit putting disable_IO_APIC earlier > causes local APIC is completely disabled. So the legacy irq mode is > disabled too before jump to kexec/kdump kernel. > > In normal kernel it defaults to be PIC mode or Virtual Wire mode during > system initialization before APIC mode is enabled and this is done by > BIOS initialization. But kexec/kdump kernel won't go through BIOS, so > we should set system as PIC or Virtual Wire mode before jump to kdump > kernel code directly. > > So let's take clear_IO_APIC out from disable_IO_APIC and rename > disable_IO_APIC as switch_to_legacy_irq_mode. Then only call clear_IO_APIC > when IO-APIC need be disabled. And call switch_to_legacy_irq_mode before > kexec/kdump jumping. > > Signed-off-by: Baoquan He > --- > arch/x86/include/asm/io_apic.h | 3 ++- > arch/x86/kernel/apic/io_apic.c | 12 ++++-------- > arch/x86/kernel/crash.c | 2 +- > arch/x86/kernel/machine_kexec_32.c | 15 +++++---------- > arch/x86/kernel/machine_kexec_64.c | 15 +++++---------- > arch/x86/kernel/reboot.c | 2 +- > 6 files changed, 18 insertions(+), 31 deletions(-) > > diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h > index a8834dd546cd..e38ad3863a2c 100644 > --- a/arch/x86/include/asm/io_apic.h > +++ b/arch/x86/include/asm/io_apic.h > @@ -192,7 +192,8 @@ static inline unsigned int io_apic_read(unsigned int apic, unsigned int reg) > > extern void setup_IO_APIC(void); > extern void enable_IO_APIC(void); > -extern void disable_IO_APIC(void); > +extern void clear_IO_APIC (void); > +extern void switch_to_legacy_irq_mode(void); > extern int IO_APIC_get_PCI_irq_vector(int bus, int devfn, int pin); > extern void print_IO_APICs(void); > #else /* !CONFIG_X86_IO_APIC */ > diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c > index 8a7963421460..a47aa915d18c 100644 > --- a/arch/x86/kernel/apic/io_apic.c > +++ b/arch/x86/kernel/apic/io_apic.c > @@ -587,7 +587,7 @@ static void clear_IO_APIC_pin(unsigned int apic, unsigned int pin) > mpc_ioapic_id(apic), pin); > } > > -static void clear_IO_APIC (void) > +void clear_IO_APIC (void) > { > int apic, pin; > > @@ -1439,15 +1439,11 @@ void native_disable_io_apic(void) > } > > /* > - * Not an __init, needed by the reboot code > + * Not an __init, needed by kexec/kdump code. > + * For safety IO-APIC and Local APIC need be cleared before this. > */ > -void disable_IO_APIC(void) > +void switch_to_legacy_irq_mode(void) > { > - /* > - * Clear the IO-APIC before rebooting: > - */ > - clear_IO_APIC(); > - > if (!nr_legacy_irqs()) > return; > > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index 10e74d4778a1..318ffeaaf55a 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -199,7 +199,7 @@ void native_machine_crash_shutdown(struct pt_regs *regs) > #ifdef CONFIG_X86_IO_APIC > /* Prevent crash_kexec() from deadlocking on ioapic_lock. */ > ioapic_zap_locks(); > - disable_IO_APIC(); > + clear_IO_APIC(); > #endif > lapic_shutdown(); > #ifdef CONFIG_HPET_TIMER > diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c > index edfede768688..7ab10d930cc6 100644 > --- a/arch/x86/kernel/machine_kexec_32.c > +++ b/arch/x86/kernel/machine_kexec_32.c > @@ -190,18 +190,13 @@ void machine_kexec(struct kimage *image) > local_irq_disable(); > hw_breakpoint_disable(); > > - if (image->preserve_context) { > #ifdef CONFIG_X86_IO_APIC > - /* > - * We need to put APICs in legacy mode so that we can > - * get timer interrupts in second kernel. kexec/kdump > - * paths already have calls to disable_IO_APIC() in > - * one form or other. kexec jump path also need > - * one. > - */ > - disable_IO_APIC(); > + /* > + * We need to put APICs in legacy mode so that we can > + * get timer interrupts in second kernel. > + */ > + switch_to_legacy_irq_mode(); > #endif > - } > > control_page = page_address(image->control_code_page); > memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE); > diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c > index 1f790cf9d38f..b5c0cbed6791 100644 > --- a/arch/x86/kernel/machine_kexec_64.c > +++ b/arch/x86/kernel/machine_kexec_64.c > @@ -288,18 +288,13 @@ void machine_kexec(struct kimage *image) > local_irq_disable(); > hw_breakpoint_disable(); > > - if (image->preserve_context) { > #ifdef CONFIG_X86_IO_APIC > - /* > - * We need to put APICs in legacy mode so that we can > - * get timer interrupts in second kernel. kexec/kdump > - * paths already have calls to disable_IO_APIC() in > - * one form or other. kexec jump path also need > - * one. > - */ > - disable_IO_APIC(); > + /* > + * We need to put APICs in legacy mode so that we can > + * get timer interrupts in second kernel. > + */ > + switch_to_legacy_irq_mode(); > #endif > - } > > control_page = page_address(image->control_code_page) + PAGE_SIZE; > memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE); > diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c > index 2126b9d27c34..b70cc0f38a29 100644 > --- a/arch/x86/kernel/reboot.c > +++ b/arch/x86/kernel/reboot.c > @@ -666,7 +666,7 @@ void native_machine_shutdown(void) > * Even without the erratum, it still makes sense to quiet IO APIC > * before disabling Local APIC. > */ > - disable_IO_APIC(); > + clear_IO_APIC(); > #endif > > #ifdef CONFIG_SMP > -- > 2.5.5 >