machine_kexec_file.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * kexec_file for LoongArch
  4 *
  5 * Author: Youling Tang <tangyouling@kylinos.cn>
  6 * Copyright (C) 2025 KylinSoft Corporation.
  7 *
  8 * Most code is derived from LoongArch port of kexec-tools
  9 */
 10
 11#define pr_fmt(fmt) "kexec_file: " fmt
 12
 13#include <linux/ioport.h>
 14#include <linux/kernel.h>
 15#include <linux/kexec.h>
 16#include <linux/memblock.h>
 17#include <linux/slab.h>
 18#include <linux/string.h>
 19#include <linux/types.h>
 20#include <linux/vmalloc.h>
 21#include <asm/bootinfo.h>
 22
 23const struct kexec_file_ops * const kexec_file_loaders[] = {
 24	&kexec_efi_ops,
 25	&kexec_elf_ops,
 26	NULL
 27};
 28
 29int arch_kimage_file_post_load_cleanup(struct kimage *image)
 30{
 31	vfree(image->elf_headers);
 32	image->elf_headers = NULL;
 33	image->elf_headers_sz = 0;
 34
 35	return kexec_image_post_load_cleanup_default(image);
 36}
 37
 38/* Add the "kexec_file" command line parameter to command line. */
 39static void cmdline_add_loader(unsigned long *cmdline_tmplen, char *modified_cmdline)
 40{
 41	int loader_strlen;
 42
 43	loader_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "kexec_file ");
 44	*cmdline_tmplen += loader_strlen;
 45}
 46
 47/* Add the "initrd=start,size" command line parameter to command line. */
 48static void cmdline_add_initrd(struct kimage *image, unsigned long *cmdline_tmplen,
 49				char *modified_cmdline, unsigned long initrd)
 50{
 51	int initrd_strlen;
 52
 53	initrd_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "initrd=0x%lx,0x%lx ",
 54		initrd, image->initrd_buf_len);
 55	*cmdline_tmplen += initrd_strlen;
 56}
 57
 58#ifdef CONFIG_CRASH_DUMP
 59
 60static int prepare_elf_headers(void **addr, unsigned long *sz)
 61{
 62	int ret, nr_ranges;
 63	uint64_t i;
 64	phys_addr_t start, end;
 65	struct crash_mem *cmem;
 66
 67	nr_ranges = 2; /* for exclusion of crashkernel region */
 68	for_each_mem_range(i, &start, &end)
 69		nr_ranges++;
 70
 71	cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
 72	if (!cmem)
 73		return -ENOMEM;
 74
 75	cmem->max_nr_ranges = nr_ranges;
 76	cmem->nr_ranges = 0;
 77	for_each_mem_range(i, &start, &end) {
 78		cmem->ranges[cmem->nr_ranges].start = start;
 79		cmem->ranges[cmem->nr_ranges].end = end - 1;
 80		cmem->nr_ranges++;
 81	}
 82
 83	/* Exclude crashkernel region */
 84	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
 85	if (ret < 0)
 86		goto out;
 87
 88	if (crashk_low_res.end) {
 89		ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
 90		if (ret < 0)
 91			goto out;
 92	}
 93
 94	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
 95
 96out:
 97	kfree(cmem);
 98	return ret;
 99}
100
101/*
102 * Add the "mem=size@start" command line parameter to command line, indicating the
103 * memory region the new kernel can use to boot into.
104 */
105static void cmdline_add_mem(unsigned long *cmdline_tmplen, char *modified_cmdline)
106{
107	int mem_strlen = 0;
108
109	mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
110		crashk_res.end - crashk_res.start + 1, crashk_res.start);
111	*cmdline_tmplen += mem_strlen;
112
113	if (crashk_low_res.end) {
114		mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
115			crashk_low_res.end - crashk_low_res.start + 1, crashk_low_res.start);
116		*cmdline_tmplen += mem_strlen;
117	}
118}
119
120/* Add the "elfcorehdr=size@start" command line parameter to command line. */
121static void cmdline_add_elfcorehdr(struct kimage *image, unsigned long *cmdline_tmplen,
122				   char *modified_cmdline, unsigned long elfcorehdr_sz)
123{
124	int elfcorehdr_strlen = 0;
125
126	elfcorehdr_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "elfcorehdr=0x%lx@0x%lx ",
127		elfcorehdr_sz, image->elf_load_addr);
128	*cmdline_tmplen += elfcorehdr_strlen;
129}
130
131#endif
132
133/*
134 * Try to add the initrd to the image. If it is not possible to find valid
135 * locations, this function will undo changes to the image and return non zero.
136 */
137int load_other_segments(struct kimage *image,
138			unsigned long kernel_load_addr, unsigned long kernel_size,
139			char *initrd, unsigned long initrd_len, char *cmdline, unsigned long cmdline_len)
140{
141	int ret = 0;
142	unsigned long cmdline_tmplen = 0;
143	unsigned long initrd_load_addr = 0;
144	unsigned long orig_segments = image->nr_segments;
145	char *modified_cmdline = NULL;
146	struct kexec_buf kbuf = {};
147
148	kbuf.image = image;
149	/* Don't allocate anything below the kernel */
150	kbuf.buf_min = kernel_load_addr + kernel_size;
151
152	modified_cmdline = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
153	if (!modified_cmdline)
154		return -EINVAL;
155
156	cmdline_add_loader(&cmdline_tmplen, modified_cmdline);
157	/* Ensure it's null terminated */
158	modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
159
160#ifdef CONFIG_CRASH_DUMP
161	/* Load elf core header */
162	if (image->type == KEXEC_TYPE_CRASH) {
163		void *headers;
164		unsigned long headers_sz;
165
166		ret = prepare_elf_headers(&headers, &headers_sz);
167		if (ret < 0) {
168			pr_err("Preparing elf core header failed\n");
169			goto out_err;
170		}
171
172		kbuf.buffer = headers;
173		kbuf.bufsz = headers_sz;
174		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
175		kbuf.memsz = headers_sz;
176		kbuf.buf_align = SZ_64K; /* largest supported page size */
177		kbuf.buf_max = ULONG_MAX;
178		kbuf.top_down = true;
179
180		ret = kexec_add_buffer(&kbuf);
181		if (ret < 0) {
182			vfree(headers);
183			goto out_err;
184		}
185		image->elf_headers = headers;
186		image->elf_load_addr = kbuf.mem;
187		image->elf_headers_sz = headers_sz;
188
189		kexec_dprintk("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
190			      image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
191
192		/* Add the mem=size@start parameter to the command line */
193		cmdline_add_mem(&cmdline_tmplen, modified_cmdline);
194
195		/* Add the elfcorehdr=size@start parameter to the command line */
196		cmdline_add_elfcorehdr(image, &cmdline_tmplen, modified_cmdline, headers_sz);
197	}
198#endif
199
200	/* Load initrd */
201	if (initrd) {
202		kbuf.buffer = initrd;
203		kbuf.bufsz = initrd_len;
204		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
205		kbuf.memsz = initrd_len;
206		kbuf.buf_align = 0;
207		/* within 1GB-aligned window of up to 32GB in size */
208		kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) + (unsigned long)SZ_1G * 32;
209		kbuf.top_down = false;
210
211		ret = kexec_add_buffer(&kbuf);
212		if (ret < 0)
213			goto out_err;
214		initrd_load_addr = kbuf.mem;
215
216		kexec_dprintk("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
217			      initrd_load_addr, kbuf.bufsz, kbuf.memsz);
218
219		/* Add the initrd=start,size parameter to the command line */
220		cmdline_add_initrd(image, &cmdline_tmplen, modified_cmdline, initrd_load_addr);
221	}
222
223	if (cmdline_len + cmdline_tmplen > COMMAND_LINE_SIZE) {
224		pr_err("Appending command line exceeds COMMAND_LINE_SIZE\n");
225		ret = -EINVAL;
226		goto out_err;
227	}
228
229	memcpy(modified_cmdline + cmdline_tmplen, cmdline, cmdline_len);
230	cmdline = modified_cmdline;
231	image->arch.cmdline_ptr = (unsigned long)cmdline;
232
233	return 0;
234
235out_err:
236	image->nr_segments = orig_segments;
237	kfree(modified_cmdline);
238	return ret;
239}