1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Load ELF vmlinux file for the kexec_file_load syscall. 4 * 5 * Author: Youling Tang <tangyouling@kylinos.cn> 6 * Copyright (C) 2025 KylinSoft Corporation. 7 */ 8 9 #define pr_fmt(fmt) "kexec_file(ELF): " fmt 10 11 #include <linux/elf.h> 12 #include <linux/kexec.h> 13 #include <linux/slab.h> 14 #include <linux/types.h> 15 #include <linux/memblock.h> 16 #include <asm/setup.h> 17 18 #define elf_kexec_probe kexec_elf_probe 19 20 static int _elf_kexec_load(struct kimage *image, 21 struct elfhdr *ehdr, struct kexec_elf_info *elf_info, 22 struct kexec_buf *kbuf, unsigned long *text_offset) 23 { 24 int i, ret = -1; 25 26 /* Read in the PT_LOAD segments. */ 27 for (i = 0; i < ehdr->e_phnum; i++) { 28 size_t size; 29 const struct elf_phdr *phdr; 30 31 phdr = &elf_info->proghdrs[i]; 32 if (phdr->p_type != PT_LOAD) 33 continue; 34 35 size = phdr->p_filesz; 36 if (size > phdr->p_memsz) 37 size = phdr->p_memsz; 38 39 kbuf->buffer = (void *)elf_info->buffer + phdr->p_offset; 40 kbuf->bufsz = size; 41 kbuf->buf_align = phdr->p_align; 42 *text_offset = __pa(phdr->p_paddr); 43 kbuf->buf_min = *text_offset; 44 kbuf->memsz = ALIGN(phdr->p_memsz, SZ_64K); 45 kbuf->mem = KEXEC_BUF_MEM_UNKNOWN; 46 ret = kexec_add_buffer(kbuf); 47 if (ret < 0) 48 break; 49 } 50 51 return ret; 52 } 53 54 static void *elf_kexec_load(struct kimage *image, 55 char *kernel, unsigned long kernel_len, 56 char *initrd, unsigned long initrd_len, 57 char *cmdline, unsigned long cmdline_len) 58 { 59 int ret; 60 unsigned long text_offset, kernel_segment_number; 61 struct elfhdr ehdr; 62 struct kexec_buf kbuf; 63 struct kexec_elf_info elf_info; 64 struct kexec_segment *kernel_segment; 65 66 ret = kexec_build_elf_info(kernel, kernel_len, &ehdr, &elf_info); 67 if (ret < 0) 68 return ERR_PTR(ret); 69 70 /* 71 * Load the kernel 72 * FIXME: Non-relocatable kernel rejected for kexec_file (require CONFIG_RELOCATABLE) 73 */ 74 kbuf.image = image; 75 kbuf.buf_max = ULONG_MAX; 76 kbuf.top_down = false; 77 78 kernel_segment_number = image->nr_segments; 79 80 ret = _elf_kexec_load(image, &ehdr, &elf_info, &kbuf, &text_offset); 81 if (ret < 0) 82 goto out; 83 84 /* Load additional data */ 85 kernel_segment = &image->segment[kernel_segment_number]; 86 ret = load_other_segments(image, kernel_segment->mem, kernel_segment->memsz, 87 initrd, initrd_len, cmdline, cmdline_len); 88 if (ret < 0) 89 goto out; 90 91 /* Make sure the second kernel jumps to the correct "kernel_entry". */ 92 image->start = kernel_segment->mem + __pa(ehdr.e_entry) - text_offset; 93 94 kexec_dprintk("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 95 kernel_segment->mem, kbuf.bufsz, kernel_segment->memsz); 96 97 out: 98 kexec_free_elf_info(&elf_info); 99 return ret ? ERR_PTR(ret) : NULL; 100 } 101 102 const struct kexec_file_ops kexec_elf_ops = { 103 .probe = elf_kexec_probe, 104 .load = elf_kexec_load, 105 }; 106