arch/powerpc/kexec/file_load.c

   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 }