LXR linux/arch/powerpc/kexec/file

   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 */
  36char *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 */
  71int 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