From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752768AbeBZLRb (ORCPT ); Mon, 26 Feb 2018 06:17:31 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47010 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751999AbeBZLR3 (ORCPT ); Mon, 26 Feb 2018 06:17:29 -0500 Date: Mon, 26 Feb 2018 12:17:18 +0100 From: Philipp Rudo To: AKASHI Takahiro 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 In-Reply-To: <20180222111732.23051-4-takahiro.akashi@linaro.org> References: <20180222111732.23051-1-takahiro.akashi@linaro.org> <20180222111732.23051-4-takahiro.akashi@linaro.org> Organization: IBM X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18022611-0040-0000-0000-00000437E848 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18022611-0041-0000-0000-000020DA0F03 Message-Id: <20180226121718.3432bbd6@ThinkPad> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-26_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802260153 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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 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 >