xref: /linux/arch/powerpc/kexec/file_load.c (revision 8be98d2f2a0a262f8bf8a0bc1fdf522b3c7aab17)
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  */
setup_kdump_cmdline(struct kimage * image,char * cmdline,unsigned long cmdline_len)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(cmdline_ptr, "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(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  */
setup_purgatory(struct kimage * image,const void * slave_code,const void * fdt,unsigned long kernel_load_addr,unsigned long fdt_load_addr)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, "purgatory_start",
84 					     slave_code_buf, SLAVE_CODE_SIZE,
85 					     true);
86 	if (ret) {
87 		kfree(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, "purgatory_start",
95 					     slave_code_buf, SLAVE_CODE_SIZE,
96 					     false);
97 	kfree(slave_code_buf);
98 
99 	ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
100 					     sizeof(kernel_load_addr), false);
101 	if (ret)
102 		return ret;
103 	ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
104 					     sizeof(fdt_load_addr), false);
105 	if (ret)
106 		return ret;
107 
108 	return 0;
109 }
110