1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * powerpc 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/setup.h> |
22 | |
23 | #define SLAVE_CODE_SIZE 256 /* First 0x100 bytes */ |
24 | |
25 | /** |
26 | * setup_kdump_cmdline - Prepend "elfcorehdr=<addr> " to command line |
27 | * of kdump kernel for exporting the core. |
28 | * @image: Kexec image |
29 | * @cmdline: Command line parameters to update. |
30 | * @cmdline_len: Length of the cmdline parameters. |
31 | * |
32 | * kdump segment must be setup before calling this function. |
33 | * |
34 | * Returns new cmdline buffer for kdump kernel on success, NULL otherwise. |
35 | */ |
36 | char *setup_kdump_cmdline(struct kimage *image, char *cmdline, |
37 | unsigned long cmdline_len) |
38 | { |
39 | int elfcorehdr_strlen; |
40 | char *cmdline_ptr; |
41 | |
42 | cmdline_ptr = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL); |
43 | if (!cmdline_ptr) |
44 | return NULL; |
45 | |
46 | elfcorehdr_strlen = sprintf(buf: cmdline_ptr, fmt: "elfcorehdr=0x%lx " , |
47 | image->elf_load_addr); |
48 | |
49 | if (elfcorehdr_strlen + cmdline_len > COMMAND_LINE_SIZE) { |
50 | pr_err("Appending elfcorehdr=<addr> exceeds cmdline size\n" ); |
51 | kfree(objp: cmdline_ptr); |
52 | return NULL; |
53 | } |
54 | |
55 | memcpy(cmdline_ptr + elfcorehdr_strlen, cmdline, cmdline_len); |
56 | // Ensure it's nul terminated |
57 | cmdline_ptr[COMMAND_LINE_SIZE - 1] = '\0'; |
58 | return cmdline_ptr; |
59 | } |
60 | |
61 | /** |
62 | * setup_purgatory - initialize the purgatory's global variables |
63 | * @image: kexec image. |
64 | * @slave_code: Slave code for the purgatory. |
65 | * @fdt: Flattened device tree for the next kernel. |
66 | * @kernel_load_addr: Address where the kernel is loaded. |
67 | * @fdt_load_addr: Address where the flattened device tree is loaded. |
68 | * |
69 | * Return: 0 on success, or negative errno on error. |
70 | */ |
71 | int setup_purgatory(struct kimage *image, const void *slave_code, |
72 | const void *fdt, unsigned long kernel_load_addr, |
73 | unsigned long fdt_load_addr) |
74 | { |
75 | unsigned int *slave_code_buf, master_entry; |
76 | int ret; |
77 | |
78 | slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL); |
79 | if (!slave_code_buf) |
80 | return -ENOMEM; |
81 | |
82 | /* Get the slave code from the new kernel and put it in purgatory. */ |
83 | ret = kexec_purgatory_get_set_symbol(image, name: "purgatory_start" , |
84 | buf: slave_code_buf, SLAVE_CODE_SIZE, |
85 | get_value: true); |
86 | if (ret) { |
87 | kfree(objp: slave_code_buf); |
88 | return ret; |
89 | } |
90 | |
91 | master_entry = slave_code_buf[0]; |
92 | memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE); |
93 | slave_code_buf[0] = master_entry; |
94 | ret = kexec_purgatory_get_set_symbol(image, name: "purgatory_start" , |
95 | buf: slave_code_buf, SLAVE_CODE_SIZE, |
96 | get_value: false); |
97 | kfree(objp: slave_code_buf); |
98 | |
99 | ret = kexec_purgatory_get_set_symbol(image, name: "kernel" , buf: &kernel_load_addr, |
100 | size: sizeof(kernel_load_addr), get_value: false); |
101 | if (ret) |
102 | return ret; |
103 | ret = kexec_purgatory_get_set_symbol(image, name: "dt_offset" , buf: &fdt_load_addr, |
104 | size: sizeof(fdt_load_addr), get_value: false); |
105 | if (ret) |
106 | return ret; |
107 | |
108 | return 0; |
109 | } |
110 | |