From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751830AbeEGFV0 (ORCPT ); Mon, 7 May 2018 01:21:26 -0400 Received: from mail-io0-f194.google.com ([209.85.223.194]:45733 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750811AbeEGFVX (ORCPT ); Mon, 7 May 2018 01:21:23 -0400 X-Google-Smtp-Source: AB8JxZrJ4mSX2d0s/LKhDRheUzQAarUnLxW9m2JkZIhONjp+gLFAMxRxHOyICP6nSXetyJRRX49Rxw== Date: Mon, 7 May 2018 14:22:09 +0900 From: AKASHI Takahiro To: James Morse Cc: catalin.marinas@arm.com, will.deacon@arm.com, dhowells@redhat.com, vgoyal@redhat.com, herbert@gondor.apana.org.au, davem@davemloft.net, dyoung@redhat.com, bhe@redhat.com, arnd@arndb.de, ard.biesheuvel@linaro.org, bhsharma@redhat.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 03/11] arm64: kexec_file: invoke the kernel without purgatory Message-ID: <20180507052208.GD11326@linaro.org> Mail-Followup-To: AKASHI Takahiro , James Morse , catalin.marinas@arm.com, will.deacon@arm.com, dhowells@redhat.com, vgoyal@redhat.com, herbert@gondor.apana.org.au, davem@davemloft.net, dyoung@redhat.com, bhe@redhat.com, arnd@arndb.de, ard.biesheuvel@linaro.org, bhsharma@redhat.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20180425062629.29404-1-takahiro.akashi@linaro.org> <20180425062629.29404-4-takahiro.akashi@linaro.org> <9c830fe8-56d8-b43a-6265-43d31dffe61a@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9c830fe8-56d8-b43a-6265-43d31dffe61a@arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 01, 2018 at 06:46:06PM +0100, James Morse wrote: > Hi Akashi, > > On 25/04/18 07:26, AKASHI Takahiro wrote: > > On arm64, purugatory would do almosty nothing. So just invoke secondary > > kernel directy by jumping into its entry code. > > (Nits: purgatory, almost, directly) Oops, I think I ran spell before ... > > > While, in this case, cpu_soft_restart() must be called with dtb address > > in the fifth argument, the behavior still stays compatible with kexec_load > > case as long as the argument is null. > > > > diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S > > index 8021b46c9743..391df91328ac 100644 > > --- a/arch/arm64/kernel/cpu-reset.S > > +++ b/arch/arm64/kernel/cpu-reset.S > > @@ -24,9 +24,9 @@ > > * > > * @el2_switch: Flag to indicate a swich to EL2 is needed. > > (Nit: switch) ditto > > * @entry: Location to jump to for soft reset. > > - * arg0: First argument passed to @entry. > > - * arg1: Second argument passed to @entry. > > - * arg2: Third argument passed to @entry. > > + * arg0: First argument passed to @entry. (relocation list) > > + * arg1: Second argument passed to @entry.(physcal kernel entry) > > (Nit: physical) ditto > > > + * arg2: Third argument passed to @entry. (physical dtb address) > > * > > * Put the CPU into the same state as it would be if it had been reset, and > > * branch to what would be the reset vector. It must be executed with the > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > > index f76ea92dff91..f7dbba00be10 100644 > > --- a/arch/arm64/kernel/machine_kexec.c > > +++ b/arch/arm64/kernel/machine_kexec.c > > @@ -205,10 +205,17 @@ void machine_kexec(struct kimage *kimage) > > * uses physical addressing to relocate the new image to its final > > * position and transfers control to the image entry point when the > > * relocation is complete. > > + * In case of kexec_file_load syscall, we directly start the kernel, > > + * skipping purgatory. > > We're not really skipping purgatory, purgatory doesn't exist! For regular kexec > the image/payload we run is up to kexec-tools. For kexec_file_load its a > kernel-image. Purgatory is a kexec-tools-ism. You are right, but in general, purgatory is expected to exist by generic kexec code and does exist on all architectures, kexec_load() or kexec_file_load(), except arm64's kexec_file_load case. So it would be nice to have some explicit notes here. > > > cpu_soft_restart(kimage != kexec_crash_image, > > - reboot_code_buffer_phys, kimage->head, kimage->start, 0); > > + reboot_code_buffer_phys, kimage->head, kimage->start, > > +#ifdef CONFIG_KEXEC_FILE > > + kimage->purgatory_info.purgatory_buf ? > > + 0 : kimage->arch.dtb_mem); > > +#else > > + 0); > > +#endif > > Where does kimage->arch.dtb_mem come from? This patch won't build until patch 8 > adds the config option, which is going to make bisecting any kexec side-effects > tricky. CONFIG_KEXEC_FILE is also used in patch #4, #5 and #6. I don't know how we can fix this as the implementation is divided into several patches. (So bisecting doesn't work anyway.) > purgatory_buf seems to only be set in kexec_purgatory_setup_kbuf(), called from > kexec_load_purgatory(), which we don't use. How does this get a value? > > Would it be better to always use kimage->arch.dtb_mem, and ensure that is 0 for > regular kexec (as we can't know where the dtb is)? (image_arg may then be a > better name). The problem is arch.dtb_mem is currently defined only if CONFIG_KEXEC_FILE. So I would like to - merge this patch with patch#8 - change the condition #ifdef CONFIG_KEXEC_FILE kimage->file_mode ? kimage->arch.dtb_mem : 0); #else 0); #endif Thanks, -Takahiro AKASHI > > Thanks, > > James From mboxrd@z Thu Jan 1 00:00:00 1970 From: takahiro.akashi@linaro.org (AKASHI Takahiro) Date: Mon, 7 May 2018 14:22:09 +0900 Subject: [PATCH v9 03/11] arm64: kexec_file: invoke the kernel without purgatory In-Reply-To: <9c830fe8-56d8-b43a-6265-43d31dffe61a@arm.com> References: <20180425062629.29404-1-takahiro.akashi@linaro.org> <20180425062629.29404-4-takahiro.akashi@linaro.org> <9c830fe8-56d8-b43a-6265-43d31dffe61a@arm.com> Message-ID: <20180507052208.GD11326@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, May 01, 2018 at 06:46:06PM +0100, James Morse wrote: > Hi Akashi, > > On 25/04/18 07:26, AKASHI Takahiro wrote: > > On arm64, purugatory would do almosty nothing. So just invoke secondary > > kernel directy by jumping into its entry code. > > (Nits: purgatory, almost, directly) Oops, I think I ran spell before ... > > > While, in this case, cpu_soft_restart() must be called with dtb address > > in the fifth argument, the behavior still stays compatible with kexec_load > > case as long as the argument is null. > > > > diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S > > index 8021b46c9743..391df91328ac 100644 > > --- a/arch/arm64/kernel/cpu-reset.S > > +++ b/arch/arm64/kernel/cpu-reset.S > > @@ -24,9 +24,9 @@ > > * > > * @el2_switch: Flag to indicate a swich to EL2 is needed. > > (Nit: switch) ditto > > * @entry: Location to jump to for soft reset. > > - * arg0: First argument passed to @entry. > > - * arg1: Second argument passed to @entry. > > - * arg2: Third argument passed to @entry. > > + * arg0: First argument passed to @entry. (relocation list) > > + * arg1: Second argument passed to @entry.(physcal kernel entry) > > (Nit: physical) ditto > > > + * arg2: Third argument passed to @entry. (physical dtb address) > > * > > * Put the CPU into the same state as it would be if it had been reset, and > > * branch to what would be the reset vector. It must be executed with the > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > > index f76ea92dff91..f7dbba00be10 100644 > > --- a/arch/arm64/kernel/machine_kexec.c > > +++ b/arch/arm64/kernel/machine_kexec.c > > @@ -205,10 +205,17 @@ void machine_kexec(struct kimage *kimage) > > * uses physical addressing to relocate the new image to its final > > * position and transfers control to the image entry point when the > > * relocation is complete. > > + * In case of kexec_file_load syscall, we directly start the kernel, > > + * skipping purgatory. > > We're not really skipping purgatory, purgatory doesn't exist! For regular kexec > the image/payload we run is up to kexec-tools. For kexec_file_load its a > kernel-image. Purgatory is a kexec-tools-ism. You are right, but in general, purgatory is expected to exist by generic kexec code and does exist on all architectures, kexec_load() or kexec_file_load(), except arm64's kexec_file_load case. So it would be nice to have some explicit notes here. > > > cpu_soft_restart(kimage != kexec_crash_image, > > - reboot_code_buffer_phys, kimage->head, kimage->start, 0); > > + reboot_code_buffer_phys, kimage->head, kimage->start, > > +#ifdef CONFIG_KEXEC_FILE > > + kimage->purgatory_info.purgatory_buf ? > > + 0 : kimage->arch.dtb_mem); > > +#else > > + 0); > > +#endif > > Where does kimage->arch.dtb_mem come from? This patch won't build until patch 8 > adds the config option, which is going to make bisecting any kexec side-effects > tricky. CONFIG_KEXEC_FILE is also used in patch #4, #5 and #6. I don't know how we can fix this as the implementation is divided into several patches. (So bisecting doesn't work anyway.) > purgatory_buf seems to only be set in kexec_purgatory_setup_kbuf(), called from > kexec_load_purgatory(), which we don't use. How does this get a value? > > Would it be better to always use kimage->arch.dtb_mem, and ensure that is 0 for > regular kexec (as we can't know where the dtb is)? (image_arg may then be a > better name). The problem is arch.dtb_mem is currently defined only if CONFIG_KEXEC_FILE. So I would like to - merge this patch with patch#8 - change the condition #ifdef CONFIG_KEXEC_FILE kimage->file_mode ? kimage->arch.dtb_mem : 0); #else 0); #endif Thanks, -Takahiro AKASHI > > Thanks, > > James From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-io0-x243.google.com ([2607:f8b0:4001:c06::243]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fFYac-0001FC-M3 for kexec@lists.infradead.org; Mon, 07 May 2018 05:21:36 +0000 Received: by mail-io0-x243.google.com with SMTP id r9-v6so32206300iod.6 for ; Sun, 06 May 2018 22:21:23 -0700 (PDT) Date: Mon, 7 May 2018 14:22:09 +0900 From: AKASHI Takahiro Subject: Re: [PATCH v9 03/11] arm64: kexec_file: invoke the kernel without purgatory Message-ID: <20180507052208.GD11326@linaro.org> References: <20180425062629.29404-1-takahiro.akashi@linaro.org> <20180425062629.29404-4-takahiro.akashi@linaro.org> <9c830fe8-56d8-b43a-6265-43d31dffe61a@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <9c830fe8-56d8-b43a-6265-43d31dffe61a@arm.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: James Morse Cc: herbert@gondor.apana.org.au, bhe@redhat.com, ard.biesheuvel@linaro.org, catalin.marinas@arm.com, bhsharma@redhat.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, dhowells@redhat.com, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, kexec@lists.infradead.org, dyoung@redhat.com, davem@davemloft.net, vgoyal@redhat.com On Tue, May 01, 2018 at 06:46:06PM +0100, James Morse wrote: > Hi Akashi, > > On 25/04/18 07:26, AKASHI Takahiro wrote: > > On arm64, purugatory would do almosty nothing. So just invoke secondary > > kernel directy by jumping into its entry code. > > (Nits: purgatory, almost, directly) Oops, I think I ran spell before ... > > > While, in this case, cpu_soft_restart() must be called with dtb address > > in the fifth argument, the behavior still stays compatible with kexec_load > > case as long as the argument is null. > > > > diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S > > index 8021b46c9743..391df91328ac 100644 > > --- a/arch/arm64/kernel/cpu-reset.S > > +++ b/arch/arm64/kernel/cpu-reset.S > > @@ -24,9 +24,9 @@ > > * > > * @el2_switch: Flag to indicate a swich to EL2 is needed. > > (Nit: switch) ditto > > * @entry: Location to jump to for soft reset. > > - * arg0: First argument passed to @entry. > > - * arg1: Second argument passed to @entry. > > - * arg2: Third argument passed to @entry. > > + * arg0: First argument passed to @entry. (relocation list) > > + * arg1: Second argument passed to @entry.(physcal kernel entry) > > (Nit: physical) ditto > > > + * arg2: Third argument passed to @entry. (physical dtb address) > > * > > * Put the CPU into the same state as it would be if it had been reset, and > > * branch to what would be the reset vector. It must be executed with the > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > > index f76ea92dff91..f7dbba00be10 100644 > > --- a/arch/arm64/kernel/machine_kexec.c > > +++ b/arch/arm64/kernel/machine_kexec.c > > @@ -205,10 +205,17 @@ void machine_kexec(struct kimage *kimage) > > * uses physical addressing to relocate the new image to its final > > * position and transfers control to the image entry point when the > > * relocation is complete. > > + * In case of kexec_file_load syscall, we directly start the kernel, > > + * skipping purgatory. > > We're not really skipping purgatory, purgatory doesn't exist! For regular kexec > the image/payload we run is up to kexec-tools. For kexec_file_load its a > kernel-image. Purgatory is a kexec-tools-ism. You are right, but in general, purgatory is expected to exist by generic kexec code and does exist on all architectures, kexec_load() or kexec_file_load(), except arm64's kexec_file_load case. So it would be nice to have some explicit notes here. > > > cpu_soft_restart(kimage != kexec_crash_image, > > - reboot_code_buffer_phys, kimage->head, kimage->start, 0); > > + reboot_code_buffer_phys, kimage->head, kimage->start, > > +#ifdef CONFIG_KEXEC_FILE > > + kimage->purgatory_info.purgatory_buf ? > > + 0 : kimage->arch.dtb_mem); > > +#else > > + 0); > > +#endif > > Where does kimage->arch.dtb_mem come from? This patch won't build until patch 8 > adds the config option, which is going to make bisecting any kexec side-effects > tricky. CONFIG_KEXEC_FILE is also used in patch #4, #5 and #6. I don't know how we can fix this as the implementation is divided into several patches. (So bisecting doesn't work anyway.) > purgatory_buf seems to only be set in kexec_purgatory_setup_kbuf(), called from > kexec_load_purgatory(), which we don't use. How does this get a value? > > Would it be better to always use kimage->arch.dtb_mem, and ensure that is 0 for > regular kexec (as we can't know where the dtb is)? (image_arg may then be a > better name). The problem is arch.dtb_mem is currently defined only if CONFIG_KEXEC_FILE. So I would like to - merge this patch with patch#8 - change the condition #ifdef CONFIG_KEXEC_FILE kimage->file_mode ? kimage->arch.dtb_mem : 0); #else 0); #endif Thanks, -Takahiro AKASHI > > Thanks, > > James _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec