From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751669AbeB0CDF (ORCPT ); Mon, 26 Feb 2018 21:03:05 -0500 Received: from mail-pl0-f68.google.com ([209.85.160.68]:33380 "EHLO mail-pl0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751396AbeB0CDD (ORCPT ); Mon, 26 Feb 2018 21:03:03 -0500 X-Google-Smtp-Source: AH8x225SsCd2MFBpTjZPMB4+MGzasljKQfH6qIiK0JurBIQpYcX5d8yPmqT9BMtmbJYEXmQTYwiqRw== Date: Tue, 27 Feb 2018 11:03:07 +0900 From: AKASHI Takahiro To: Philipp Rudo Cc: catalin.marinas@arm.com, will.deacon@arm.com, bauerman@linux.vnet.ibm.com, dhowells@redhat.com, vgoyal@redhat.com, herbert@gondor.apana.org.au, davem@davemloft.net, akpm@linux-foundation.org, mpe@ellerman.id.au, dyoung@redhat.com, bhe@redhat.com, arnd@arndb.de, ard.biesheuvel@linaro.org, julien.thierry@arm.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v8 03/13] kexec_file, x86, powerpc: factor out kexec_file_ops functions Message-ID: <20180227020304.GE6019@linaro.org> Mail-Followup-To: AKASHI Takahiro , Philipp Rudo , catalin.marinas@arm.com, will.deacon@arm.com, bauerman@linux.vnet.ibm.com, dhowells@redhat.com, vgoyal@redhat.com, herbert@gondor.apana.org.au, davem@davemloft.net, akpm@linux-foundation.org, mpe@ellerman.id.au, dyoung@redhat.com, bhe@redhat.com, arnd@arndb.de, ard.biesheuvel@linaro.org, julien.thierry@arm.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20180222111732.23051-1-takahiro.akashi@linaro.org> <20180222111732.23051-4-takahiro.akashi@linaro.org> <20180226121718.3432bbd6@ThinkPad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180226121718.3432bbd6@ThinkPad> 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 Mon, Feb 26, 2018 at 12:17:18PM +0100, Philipp Rudo wrote: > Hi AKASHI > > On Thu, 22 Feb 2018 20:17:22 +0900 > AKASHI Takahiro wrote: > > [...] > > > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > > index 990adae52151..a6d14a768b3e 100644 > > --- a/kernel/kexec_file.c > > +++ b/kernel/kexec_file.c > > @@ -26,34 +26,83 @@ > > #include > > #include "kexec_internal.h" > > > > +const __weak struct kexec_file_ops * const kexec_file_loaders[] = {NULL}; > > + > > Having a weak definition of kexec_file_loaders causes trouble on s390 with > gcc 4.8 (newer versions seem to work fine). For me it looks like that in this > version gcc doesn't recognize __weak but use the default value for > optimization. This leads to _kexec_kernel_image_probe to always return ENOEXEC > because the for-loop gets optimized out. I gave it a try to compile with gcc 4.9 (not 4.8) for arm64 and didn't see any errors or warnings, but > The problem can easily be worked around by declaring kexec_file_loaders in > include/linux/kexec.h and defining it in arch code. In particular doing this > > diff --git a/include/linux/kexec.h b/include/linux/kexec.h > index 37e9dce518aa..fc0788540d90 100644 > --- a/include/linux/kexec.h > +++ b/include/linux/kexec.h > @@ -139,6 +139,8 @@ struct kexec_file_ops { > #endif > }; > > +extern const struct kexec_file_ops * const kexec_file_loaders[]; > + > /** > * struct kexec_buf - parameters for finding a place for a buffer in memory > * @image: kexec image in which memory to search. > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > index 17ba407d0e79..4e3d1e4bc7f6 100644 > --- a/kernel/kexec_file.c > +++ b/kernel/kexec_file.c > @@ -31,8 +31,6 @@ > #include > #include "kexec_internal.h" > > -const __weak struct kexec_file_ops * const kexec_file_loaders[] = {NULL}; > - > #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY > static int kexec_calculate_store_digests(struct kimage *image); > #else Your change is just fine with me, too. I will incorporate it in my next version. Thanks, -Takahiro AKASHI > A nice side effect of this solution is, that a developer who forgets to define > kexec_file_loaders gets a linker error. So he directly knows what's missing > instead of first having to find out where/why an error gets returned. > > Otherwise the series is fine for me. > > Thanks > Philipp > > > #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY > > static int kexec_calculate_store_digests(struct kimage *image); > > #else > > static int kexec_calculate_store_digests(struct kimage *image) { return 0; }; > > #endif > > > > +int _kexec_kernel_image_probe(struct kimage *image, void *buf, > > + unsigned long buf_len) > > +{ > > + const struct kexec_file_ops * const *fops; > > + int ret = -ENOEXEC; > > + > > + for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) { > > + ret = (*fops)->probe(buf, buf_len); > > + if (!ret) { > > + image->fops = *fops; > > + return ret; > > + } > > + } > > + > > + return ret; > > +} > > + > > /* Architectures can provide this probe function */ > > int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, > > unsigned long buf_len) > > { > > - return -ENOEXEC; > > + return _kexec_kernel_image_probe(image, buf, buf_len); > > +} > > + > > +void *_kexec_kernel_image_load(struct kimage *image) > > +{ > > + if (!image->fops || !image->fops->load) > > + return ERR_PTR(-ENOEXEC); > > + > > + return image->fops->load(image, image->kernel_buf, > > + image->kernel_buf_len, image->initrd_buf, > > + image->initrd_buf_len, image->cmdline_buf, > > + image->cmdline_buf_len); > > } > > > > void * __weak arch_kexec_kernel_image_load(struct kimage *image) > > { > > - return ERR_PTR(-ENOEXEC); > > + return _kexec_kernel_image_load(image); > > +} > > + > > +int _kimage_file_post_load_cleanup(struct kimage *image) > > +{ > > + if (!image->fops || !image->fops->cleanup) > > + return 0; > > + > > + return image->fops->cleanup(image->image_loader_data); > > } > > > > int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) > > { > > - return -EINVAL; > > + return _kimage_file_post_load_cleanup(image); > > } > > > > #ifdef CONFIG_KEXEC_VERIFY_SIG > > +int _kexec_kernel_verify_sig(struct kimage *image, void *buf, > > + unsigned long buf_len) > > +{ > > + if (!image->fops || !image->fops->verify_sig) { > > + pr_debug("kernel loader does not support signature verification.\n"); > > + return -EKEYREJECTED; > > + } > > + > > + return image->fops->verify_sig(buf, buf_len); > > +} > > + > > int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, > > unsigned long buf_len) > > { > > - return -EKEYREJECTED; > > + return _kexec_kernel_verify_sig(image, buf, buf_len); > > } > > #endif > > >