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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9B26C77B7A for ; Fri, 19 May 2023 21:36:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229870AbjESVgl (ORCPT ); Fri, 19 May 2023 17:36:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229788AbjESVgk (ORCPT ); Fri, 19 May 2023 17:36:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 164D3FB; Fri, 19 May 2023 14:36:38 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A6B156130E; Fri, 19 May 2023 21:36:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB353C433D2; Fri, 19 May 2023 21:36:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1684532197; bh=l35e2dTKuxYIv3AwWoUZwqW/L9F98Nv7KOQTMjQN8Cs=; h=Date:To:From:Subject:From; b=1eECqefD0obQndkmxuQwOk9/Qo8rniytzKzHdEXK0eATw3KGKQ4rg1B52u41rdF6S 04X1D9SPeuENkM5Lkj4vGor2HFz+O4kS1AcEuBkZOwYmYhYXWhMEhtkTLj00ZZjTRU hl+Q2W/jbIQXRZ3Rk19JPFwLB9WZunU7lYWhbCmk= Date: Fri, 19 May 2023 14:36:36 -0700 To: mm-commits@vger.kernel.org, zwisler@google.com, trix@redhat.com, tglx@linutronix.de, stable@vger.kernel.org, rostedt@goodmis.org, prudo@redhat.com, paul.walmsley@sifive.com, palmer@rivosinc.com, palmer@dabbelt.com, npiggin@gmail.com, ndesaulniers@google.com, nathan@kernel.org, mpe@ellerman.id.au, mingo@redhat.com, hpa@zytor.com, horms@kernel.org, ebiederm@xmission.com, dyoung@redhat.com, dave.hansen@linux.intel.com, christophe.leroy@csgroup.eu, bp@alien8.de, bhe@redhat.com, aou@eecs.berkeley.edu, ribalda@chromium.org, akpm@linux-foundation.org From: Andrew Morton Subject: + kexec-support-purgatories-with-texthot-sections.patch added to mm-hotfixes-unstable branch Message-Id: <20230519213636.EB353C433D2@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: kexec: support purgatories with .text.hot sections has been added to the -mm mm-hotfixes-unstable branch. Its filename is kexec-support-purgatories-with-texthot-sections.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kexec-support-purgatories-with-texthot-sections.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Ricardo Ribalda Subject: kexec: support purgatories with .text.hot sections Date: Fri, 19 May 2023 16:47:36 +0200 Patch series "kexec: Fix kexec_file_load for llvm16 with PGO", v7. When upreving llvm I realised that kexec stopped working on my test platform. The reason seems to be that due to PGO there are multiple .text sections on the purgatory, and kexec does not supports that. This patch (of 4): Clang16 links the purgatory text in two sections when PGO is in use: [ 1] .text PROGBITS 0000000000000000 00000040 00000000000011a1 0000000000000000 AX 0 0 16 [ 2] .rela.text RELA 0000000000000000 00003498 0000000000000648 0000000000000018 I 24 1 8 ... [17] .text.hot. PROGBITS 0000000000000000 00003220 000000000000020b 0000000000000000 AX 0 0 1 [18] .rela.text.hot. RELA 0000000000000000 00004428 0000000000000078 0000000000000018 I 24 17 8 And both of them have their range [sh_addr ... sh_addr+sh_size] on the area pointed by `e_entry`. This causes that image->start is calculated twice, once for .text and another time for .text.hot. The second calculation leaves image->start in a random location. Because of this, the system crashes immediately after: kexec_core: Starting new kernel Link: https://lkml.kernel.org/r/20230321-kexec_clang16-v7-0-b05c520b7296@chromium.org Link: https://lkml.kernel.org/r/20230321-kexec_clang16-v7-1-b05c520b7296@chromium.org Fixes: 930457057abe ("kernel/kexec_file.c: split up __kexec_load_puragory") Signed-off-by: Ricardo Ribalda Reviewed-by: Ross Zwisler Reviewed-by: Steven Rostedt (Google) Reviewed-by: Philipp Rudo Cc: Albert Ou Cc: Baoquan He Cc: Borislav Petkov (AMD) Cc: Christophe Leroy Cc: Dave Hansen Cc: Dave Young Cc: Eric W. Biederman Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Michael Ellerman Cc: Nathan Chancellor Cc: Nicholas Piggin Cc: Nick Desaulniers Cc: Palmer Dabbelt Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Simon Horman Cc: Thomas Gleixner Cc: Tom Rix Cc: Signed-off-by: Andrew Morton --- kernel/kexec_file.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) --- a/kernel/kexec_file.c~kexec-support-purgatories-with-texthot-sections +++ a/kernel/kexec_file.c @@ -901,10 +901,22 @@ static int kexec_purgatory_setup_sechdrs } offset = ALIGN(offset, align); + + /* + * Check if the segment contains the entry point, if so, + * calculate the value of image->start based on it. + * If the compiler has produced more than one .text section + * (Eg: .text.hot), they are generally after the main .text + * section, and they shall not be used to calculate + * image->start. So do not re-calculate image->start if it + * is not set to the initial value, and warn the user so they + * have a chance to fix their purgatory's linker script. + */ if (sechdrs[i].sh_flags & SHF_EXECINSTR && pi->ehdr->e_entry >= sechdrs[i].sh_addr && pi->ehdr->e_entry < (sechdrs[i].sh_addr - + sechdrs[i].sh_size)) { + + sechdrs[i].sh_size) && + !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) { kbuf->image->start -= sechdrs[i].sh_addr; kbuf->image->start += kbuf->mem + offset; } _ Patches currently in -mm which might be from ribalda@chromium.org are kexec-support-purgatories-with-texthot-sections.patch x86-purgatory-remove-pgo-flags.patch powerpc-purgatory-remove-pgo-flags.patch riscv-purgatory-remove-pgo-flags.patch