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(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 */ 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