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}