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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ppc64 code to implement the kexec_file_load syscall
4 *
5 * Copyright (C) 2004 Adam Litke (agl@us.ibm.com)
6 * Copyright (C) 2004 IBM Corp.
7 * Copyright (C) 2004,2005 Milton D Miller II, IBM Corporation
8 * Copyright (C) 2005 R Sharada (sharada@in.ibm.com)
9 * Copyright (C) 2006 Mohan Kumar M (mohan@in.ibm.com)
10 * Copyright (C) 2016 IBM Corporation
11 *
12 * Based on kexec-tools' kexec-elf-ppc64.c, fs2dt.c.
13 * Heavily modified for the kernel by
14 * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
15 */
16
17#include <linux/slab.h>
18#include <linux/kexec.h>
19#include <linux/of_fdt.h>
20#include <linux/libfdt.h>
21#include <asm/ima.h>
22
23#define SLAVE_CODE_SIZE 256
24
25const struct kexec_file_ops * const kexec_file_loaders[] = {
26 &kexec_elf64_ops,
27 NULL
28};
29
30int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
31 unsigned long buf_len)
32{
33 /* We don't support crash kernels yet. */
34 if (image->type == KEXEC_TYPE_CRASH)
35 return -EOPNOTSUPP;
36
37 return kexec_image_probe_default(image, buf, buf_len);
38}
39
40/**
41 * setup_purgatory - initialize the purgatory's global variables
42 * @image: kexec image.
43 * @slave_code: Slave code for the purgatory.
44 * @fdt: Flattened device tree for the next kernel.
45 * @kernel_load_addr: Address where the kernel is loaded.
46 * @fdt_load_addr: Address where the flattened device tree is loaded.
47 *
48 * Return: 0 on success, or negative errno on error.
49 */
50int setup_purgatory(struct kimage *image, const void *slave_code,
51 const void *fdt, unsigned long kernel_load_addr,
52 unsigned long fdt_load_addr)
53{
54 unsigned int *slave_code_buf, master_entry;
55 int ret;
56
57 slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
58 if (!slave_code_buf)
59 return -ENOMEM;
60
61 /* Get the slave code from the new kernel and put it in purgatory. */
62 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
63 slave_code_buf, SLAVE_CODE_SIZE,
64 true);
65 if (ret) {
66 kfree(slave_code_buf);
67 return ret;
68 }
69
70 master_entry = slave_code_buf[0];
71 memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
72 slave_code_buf[0] = master_entry;
73 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
74 slave_code_buf, SLAVE_CODE_SIZE,
75 false);
76 kfree(slave_code_buf);
77
78 ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
79 sizeof(kernel_load_addr), false);
80 if (ret)
81 return ret;
82 ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
83 sizeof(fdt_load_addr), false);
84 if (ret)
85 return ret;
86
87 return 0;
88}
89
90/**
91 * delete_fdt_mem_rsv - delete memory reservation with given address and size
92 *
93 * Return: 0 on success, or negative errno on error.
94 */
95int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
96{
97 int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
98
99 for (i = 0; i < num_rsvs; i++) {
100 uint64_t rsv_start, rsv_size;
101
102 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
103 if (ret) {
104 pr_err("Malformed device tree.\n");
105 return -EINVAL;
106 }
107
108 if (rsv_start == start && rsv_size == size) {
109 ret = fdt_del_mem_rsv(fdt, i);
110 if (ret) {
111 pr_err("Error deleting device tree reservation.\n");
112 return -EINVAL;
113 }
114
115 return 0;
116 }
117 }
118
119 return -ENOENT;
120}
121
122/*
123 * setup_new_fdt - modify /chosen and memory reservation for the next kernel
124 * @image: kexec image being loaded.
125 * @fdt: Flattened device tree for the next kernel.
126 * @initrd_load_addr: Address where the next initrd will be loaded.
127 * @initrd_len: Size of the next initrd, or 0 if there will be none.
128 * @cmdline: Command line for the next kernel, or NULL if there will
129 * be none.
130 *
131 * Return: 0 on success, or negative errno on error.
132 */
133int setup_new_fdt(const struct kimage *image, void *fdt,
134 unsigned long initrd_load_addr, unsigned long initrd_len,
135 const char *cmdline)
136{
137 int ret, chosen_node;
138 const void *prop;
139
140 /* Remove memory reservation for the current device tree. */
141 ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
142 fdt_totalsize(initial_boot_params));
143 if (ret == 0)
144 pr_debug("Removed old device tree reservation.\n");
145 else if (ret != -ENOENT)
146 return ret;
147
148 chosen_node = fdt_path_offset(fdt, "/chosen");
149 if (chosen_node == -FDT_ERR_NOTFOUND) {
150 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
151 "chosen");
152 if (chosen_node < 0) {
153 pr_err("Error creating /chosen.\n");
154 return -EINVAL;
155 }
156 } else if (chosen_node < 0) {
157 pr_err("Malformed device tree: error reading /chosen.\n");
158 return -EINVAL;
159 }
160
161 /* Did we boot using an initrd? */
162 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
163 if (prop) {
164 uint64_t tmp_start, tmp_end, tmp_size;
165
166 tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));
167
168 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL);
169 if (!prop) {
170 pr_err("Malformed device tree.\n");
171 return -EINVAL;
172 }
173 tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop));
174
175 /*
176 * kexec reserves exact initrd size, while firmware may
177 * reserve a multiple of PAGE_SIZE, so check for both.
178 */
179 tmp_size = tmp_end - tmp_start;
180 ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
181 if (ret == -ENOENT)
182 ret = delete_fdt_mem_rsv(fdt, tmp_start,
183 round_up(tmp_size, PAGE_SIZE));
184 if (ret == 0)
185 pr_debug("Removed old initrd reservation.\n");
186 else if (ret != -ENOENT)
187 return ret;
188
189 /* If there's no new initrd, delete the old initrd's info. */
190 if (initrd_len == 0) {
191 ret = fdt_delprop(fdt, chosen_node,
192 "linux,initrd-start");
193 if (ret) {
194 pr_err("Error deleting linux,initrd-start.\n");
195 return -EINVAL;
196 }
197
198 ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
199 if (ret) {
200 pr_err("Error deleting linux,initrd-end.\n");
201 return -EINVAL;
202 }
203 }
204 }
205
206 if (initrd_len) {
207 ret = fdt_setprop_u64(fdt, chosen_node,
208 "linux,initrd-start",
209 initrd_load_addr);
210 if (ret < 0)
211 goto err;
212
213 /* initrd-end is the first address after the initrd image. */
214 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
215 initrd_load_addr + initrd_len);
216 if (ret < 0)
217 goto err;
218
219 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
220 if (ret) {
221 pr_err("Error reserving initrd memory: %s\n",
222 fdt_strerror(ret));
223 return -EINVAL;
224 }
225 }
226
227 if (cmdline != NULL) {
228 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
229 if (ret < 0)
230 goto err;
231 } else {
232 ret = fdt_delprop(fdt, chosen_node, "bootargs");
233 if (ret && ret != -FDT_ERR_NOTFOUND) {
234 pr_err("Error deleting bootargs.\n");
235 return -EINVAL;
236 }
237 }
238
239 ret = setup_ima_buffer(image, fdt, chosen_node);
240 if (ret) {
241 pr_err("Error setting up the new device tree.\n");
242 return ret;
243 }
244
245 ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
246 if (ret)
247 goto err;
248
249 return 0;
250
251err:
252 pr_err("Error setting up the new device tree.\n");
253 return -EINVAL;
254}