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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 80086CA0EEB for ; Thu, 21 Aug 2025 09:39:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hAJlHDvRqPXZP6gjpMtCItfPezDjP3bZ9+iZXylcguQ=; b=OCQefbHGd2l/M52nxfz1DnhIAl yluq8Pcvo5THpMnXa4UUwSnNUQixL59XTB1UoNDyC06y+q5x2/q9f/YeUy9u3hfdwf50C+UhsNZcI C6POBDjAsttqhTSAlQduizbgAULS/DynrFRfKAspyPD8+W+mEcFZqtTiFC0+YELRcbhWUimt/QB9h OCzl8aaKd2AgHvuzJ5h6hsl7bqgcM0cFjs1GNbyr7XIkR4ZLzSj50wujptbzMU7/FmnlTPxMOIpvM YhIgIml734OwXMnAshPsDM2AGKZ19xhAPIHxsSBXUX9HBjhXdCuCyu4nGISda8Key/pSlngrNzGBP RZAyKufw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1up1ln-0000000GQCj-11Mo; Thu, 21 Aug 2025 09:39:43 +0000 Received: from out-186.mta0.migadu.com ([2001:41d0:1004:224b::ba]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uozWG-0000000G4ZA-2oWI for kexec@lists.infradead.org; Thu, 21 Aug 2025 07:15:35 +0000 Message-ID: <284a663f-3bdd-4dcc-b017-b1b3fe6d9eb1@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1755760526; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hAJlHDvRqPXZP6gjpMtCItfPezDjP3bZ9+iZXylcguQ=; b=knxq+tVimd9IbWYeagAu12XA+IPT9X5xTur4GrkRgf067Tk/mT3o5S0OPrDr0B1l9PKhga 52EcIZ52FIgtIwgx/QZTcynLtOlcpA+PLTsRbTdL4qA9kjrvZFC9x1RW5a3riqeJWzp5Qz OKJI161XwmCJRjhiLChhKQj4WusaqA4= Date: Thu, 21 Aug 2025 15:14:46 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v2 3/5] LoongArch/kexec_file: Support loading ELF binary file To: Huacai Chen Cc: WANG Xuerui , Baoquan He , Yao Zi , kexec@lists.infradead.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, Youling Tang References: <20250820055700.24344-1-youling.tang@linux.dev> <20250820055700.24344-4-youling.tang@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Youling Tang In-Reply-To: <20250820055700.24344-4-youling.tang@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250821_001533_450145_C706CEF2 X-CRM114-Status: GOOD ( 33.45 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 2025/8/20 13:56, Youling Tang wrote: > From: Youling Tang > > This patch creates kexec_elf_ops to load ELF binary file > for kexec_file_load() syscall. > > Signed-off-by: Youling Tang > --- > arch/loongarch/Kconfig | 1 + > arch/loongarch/include/asm/kexec.h | 1 + > arch/loongarch/kernel/Makefile | 2 +- > arch/loongarch/kernel/kexec_elf.c | 105 +++++++++++++++++++++ > arch/loongarch/kernel/machine_kexec_file.c | 1 + > 5 files changed, 109 insertions(+), 1 deletion(-) > create mode 100644 arch/loongarch/kernel/kexec_elf.c > > diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig > index 490dc6eed749..bf2664ed7ce3 100644 > --- a/arch/loongarch/Kconfig > +++ b/arch/loongarch/Kconfig > @@ -632,6 +632,7 @@ config ARCH_SELECTS_KEXEC_FILE > def_bool y > depends on KEXEC_FILE > select HAVE_IMA_KEXEC if IMA > + select KEXEC_ELF > select RELOCATABLE > > config ARCH_SUPPORTS_CRASH_DUMP > diff --git a/arch/loongarch/include/asm/kexec.h b/arch/loongarch/include/asm/kexec.h > index 34799db933fb..fecfb3015abc 100644 > --- a/arch/loongarch/include/asm/kexec.h > +++ b/arch/loongarch/include/asm/kexec.h > @@ -43,6 +43,7 @@ struct kimage_arch { > > #ifdef CONFIG_KEXEC_FILE > extern const struct kexec_file_ops kexec_efi_ops; > +extern const struct kexec_file_ops kexec_elf_ops; > > int arch_kimage_file_post_load_cleanup(struct kimage *image); > #define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup > diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile > index dd6183f353e6..001924877772 100644 > --- a/arch/loongarch/kernel/Makefile > +++ b/arch/loongarch/kernel/Makefile > @@ -62,7 +62,7 @@ obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o > obj-$(CONFIG_RELOCATABLE) += relocate.o > > obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o > -obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o kexec_efi.o > +obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o kexec_efi.o kexec_elf.o > obj-$(CONFIG_CRASH_DUMP) += crash_dump.o > > obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o > diff --git a/arch/loongarch/kernel/kexec_elf.c b/arch/loongarch/kernel/kexec_elf.c > new file mode 100644 > index 000000000000..d41ee5fd7cef > --- /dev/null > +++ b/arch/loongarch/kernel/kexec_elf.c > @@ -0,0 +1,105 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Load ELF vmlinux file for the kexec_file_load syscall. > + * > + * Author: Youling Tang > + * Copyright (C) 2025 KylinSoft Corporation. > + */ > + > +#define pr_fmt(fmt) "kexec_file(ELF): " fmt > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static int loongarch_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info, > + struct kexec_buf *kbuf, > + unsigned long *text_offset) > +{ > + int ret = -1; > + size_t i; > + > + /* Read in the PT_LOAD segments. */ > + for (i = 0; i < ehdr->e_phnum; i++) { > + size_t size; > + const struct elf_phdr *phdr; > + struct loongarch_image_header *header; > + > + phdr = &elf_info->proghdrs[i]; > + if (phdr->p_type != PT_LOAD) > + continue; > + > + size = phdr->p_filesz; > + if (size > phdr->p_memsz) > + size = phdr->p_memsz; > + > + kbuf->buffer = (void *)elf_info->buffer + phdr->p_offset; > + kbuf->bufsz = size; > + kbuf->buf_align = phdr->p_align; > + header = (struct loongarch_image_header *)kbuf->buffer; > + *text_offset = le64_to_cpu(header->text_offset); > + kbuf->buf_min = *text_offset; > + kbuf->memsz = le64_to_cpu(header->image_size); Elf kernel resolution should not be used to struct loongarch_image_header, members of the content contained in the inner world of CONFIG_EFI_STUB in the arch/loongarch/kernel/head.S, should use the content inside the elf header information, The kexec-tools tool should also be fixed. However, there is certain content in the elf header information, and the general kexec_elf_load() function cannot be used. Special processing of kbuf->memsz and kbuf->memsz is required. $ readelf -l vmlinux ...   Type           Offset             VirtAddr           PhysAddr                  FileSiz            MemSiz              Flags Align   LOAD           0x0000000000010000 0x9000000000200000 0x9000000000200000                  0x0000000002747a00 0x000000000287a0d8  RWE 0x10000   NOTE           0x0000000000000000 0x0000000000000000 0x0000000000000000                  0x0000000000000000 0x0000000000000000  R      0x8 phdr->p_paddr should have been a physical address, but it is a virtual address on the current LoongArch. This will cause kexec_file to fail when loading the kernel and need to be converted to a physical address. Another patch is working to fix this issue[1]. From the above MemSiz, it can be seen that 0x287a0d8 has not been aligned. Although kexec_add_buffer() will perform PAGE_SIZE alignment on kbuf->memsz, there is still a stampeding in the loaded kernel space and initrd space. The initrd resolution failed when starting the second kernel. It can be known from the link script vmlinux.lds.S that,    BSS_SECTION(0, SZ_64K, 8)    . = ALIGN(PECOFF_SEGMENT_ALIGN); It needs to be aligned according to the SZ_64K size, so that after alignment, its size is consistent with _kernel_asize (loongarch_image_header->image_size). The following modifications will be used in the next version to fix it， --- a/arch/loongarch/kernel/kexec_elf.c +++ b/arch/loongarch/kernel/kexec_elf.c @@ -28,7 +28,6 @@ static int loongarch_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,         for (i = 0; i < ehdr->e_phnum; i++) {                 size_t size;                 const struct elf_phdr *phdr; -               struct loongarch_image_header *header;                 phdr = &elf_info->proghdrs[i];                 if (phdr->p_type != PT_LOAD) @@ -41,10 +40,9 @@ static int loongarch_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,                 kbuf->buffer = (void *)elf_info->buffer + phdr->p_offset;                 kbuf->bufsz = size;                 kbuf->buf_align = phdr->p_align; -               header = (struct loongarch_image_header *)kbuf->buffer; -               *text_offset = le64_to_cpu(header->text_offset); -               kbuf->buf_min = *text_offset; -               kbuf->memsz = le64_to_cpu(header->image_size); +               *text_offset = __pa(phdr->p_paddr); +               kbuf->buf_min = _*text_offset; +               kbuf->memsz = ALIGN(phdr->p_memsz, SZ_64K);                 kbuf->mem = KEXEC_BUF_MEM_UNKNOWN; [1]: https://lore.kernel.org/loongarch/00651F3A-6649-4C69-B365-352C8D323902@flygoat.com/T/#t Thanks, Youling. > + kbuf->mem = KEXEC_BUF_MEM_UNKNOWN; > + ret = kexec_add_buffer(kbuf); > + if (ret) > + break; > + } > + > + return ret; > +} > + > +static void *elf_kexec_load(struct kimage *image, char *kernel_buf, > + unsigned long kernel_len, char *initrd, > + unsigned long initrd_len, char *cmdline, > + unsigned long cmdline_len) > +{ > + int ret; > + unsigned long text_offset = 0, kernel_segment_number; > + struct elfhdr ehdr; > + struct kexec_elf_info elf_info; > + struct kexec_segment *kernel_segment; > + struct kexec_buf kbuf; > + > + ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info); > + if (ret) > + return ERR_PTR(ret); > + > + /* Load the kernel */ > + kbuf.image = image; > + kbuf.buf_max = ULONG_MAX; > + kbuf.top_down = false; > + > + kernel_segment_number = image->nr_segments; > + > + ret = loongarch_kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &text_offset); > + if (ret) > + goto out; > + > + /* Load additional data */ > + kernel_segment = &image->segment[kernel_segment_number]; > + ret = load_other_segments(image, kernel_segment->mem, kernel_segment->memsz, > + initrd, initrd_len, cmdline, cmdline_len); > + if (ret) > + goto out; > + > + /* Make sure the second kernel jumps to the correct "kernel_entry". */ > + image->start = kernel_segment->mem + __pa(ehdr.e_entry) - text_offset; > + > + kexec_dprintk("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n", > + kernel_segment->mem, kbuf.bufsz, kernel_segment->memsz); > + > +out: > + kexec_free_elf_info(&elf_info); > + return ret ? ERR_PTR(ret) : NULL; > +} > + > +const struct kexec_file_ops kexec_elf_ops = { > + .probe = kexec_elf_probe, > + .load = elf_kexec_load, > +}; > diff --git a/arch/loongarch/kernel/machine_kexec_file.c b/arch/loongarch/kernel/machine_kexec_file.c > index a713acf32db8..dc6e37457559 100644 > --- a/arch/loongarch/kernel/machine_kexec_file.c > +++ b/arch/loongarch/kernel/machine_kexec_file.c > @@ -22,6 +22,7 @@ > > const struct kexec_file_ops * const kexec_file_loaders[] = { > &kexec_efi_ops, > + &kexec_elf_ops, > NULL > }; >