/*
* kexec.c - kexec system call core code.
* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/kexec.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/ioport.h>
#include <linux/hardirq.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/utsname.h>
#include <linux/numa.h>
#include <linux/suspend.h>
#include <linux/device.h>
#include <linux/freezer.h>
#include <linux/pm.h>
#include <linux/cpu.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/swap.h>
#include <linux/syscore_ops.h>
#include <linux/compiler.h>
#include <linux/hugetlb.h>
#include <linux/frame.h>
#include <asm/page.h>
#include <asm/sections.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include "kexec_internal.h"
DEFINE_MUTEX(kexec_mutex);
/* Per cpu memory for storing cpu states in case of system crash. */
note_buf_t __percpu *crash_notes;
/* Flag to indicate we are going to kexec a new kernel */
bool kexec_in_progress = false;
/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
struct resource crashk_low_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
int kexec_should_crash(struct task_struct *p)
{
/*
* If crash_kexec_post_notifiers is enabled, don't run
* crash_kexec() here yet, which must be run after panic
* notifiers in panic().
*/
if (crash_kexec_post_notifiers)
return 0;
/*
* There are 4 panic() calls in do_exit() path, each of which
* corresponds to each of these 4 conditions.
*/
if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
return 1;
return 0;
}
int kexec_crash_loaded(void)
{
return !!kexec_crash_image;
}
EXPORT_SYMBOL_GPL(kexec_crash_loaded);
/*
* When kexec transitions to the new kernel there is a one-to-one
* mapping between physical and virtual addresses. On processors
* where you can disable the MMU this is trivial, and easy. For
* others it is still a simple predictable page table to setup.
*
* In that environment kexec copies the new kernel to its final
* resting place. This means I can only support memory whose
* physical address can fit in an unsigned long. In particular
* addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
* If the assembly stub has more restrictive requirements
* KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
* defined more restrictively in <asm/kexec.h>.
*
* The code for the transition from the current kernel to the
* the new kernel is placed in the control_code_buffer, whose size
* is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
* page of memory is necessary, but some architectures require more.
* Because this memory must be identity mapped in the transition from
* virtual to physical addresses it must live in the range
* 0 - TASK_SIZE, as only the user space mappings are arbitrarily
* modifiable.
*
* The assembly stub in the control code buffer is passed a linked list
* of descriptor pages detailing the source pages of the new kernel,
* and the destination addresses of those source pages. As this data
* structure is not used in the context of the current OS, it must
* be self-contained.
*
* The code has been made to work with highmem pages and will use a
* destination page in its final resting place (if it happens
* to allocate it). The end product of this is that most of the
* physical address space, and most of RAM can be used.
*
* Future directions include:
* - allocating a page table with the control code buffer identity
* mapped, to simplify machine_kexec and make kexec_on_panic more
* reliable.
*/
/*
* KIMAGE_NO_DEST is an impossible destination address..., for
* allocating pages whose destination address we do not care about.
*/
#define KIMAGE_NO_DEST (-1UL)
#define PAGE_COUNT(x) (((x) + PAGE_SIZE - 1) >> PAGE_SHIFT)
static struct page *kimage_alloc_page(struct kimage *image,
gfp_t gfp_mask,
unsigned long dest);
int sanity_check_segment_list(struct kimage *image)
{
int i;
unsigned long nr_segments = image->nr_segments;
unsigned long total_pages = 0;
unsign