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![Russell King](/assets/img/avatar_default.png)
kexec physical addresses are the boot-time view of the system. For certain ARM systems (such as Keystone 2), the boot view of the system does not match the kernel's view of the system: the boot view uses a special alias in the lower 4GB of the physical address space. To cater for these kinds of setups, we need to translate between the boot view physical addresses and the normal kernel view physical addresses. This patch extracts the current transation points into linux/kexec.h, and allows an architecture to override the functions. Due to the translations required, we unfortunately end up with six translation functions, which are reduced down to four that the architecture can override. [akpm@linux-foundation.org: kexec.h needs asm/io.h for phys_to_virt()] Link: http://lkml.kernel.org/r/E1b8koP-0004HZ-Vf@rmk-PC.armlinux.org.uk Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Keerthy <j-keerthy@ti.com> Cc: Pratyush Anand <panand@redhat.com> Cc: Vitaly Andrianov <vitalya@ti.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Simon Horman <horms@verge.net.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
269 lines
6.8 KiB
C
269 lines
6.8 KiB
C
/*
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* kexec.c - kexec_load system call
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* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/capability.h>
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#include <linux/mm.h>
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#include <linux/file.h>
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#include <linux/kexec.h>
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#include <linux/mutex.h>
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#include <linux/list.h>
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#include <linux/syscalls.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include "kexec_internal.h"
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static int copy_user_segment_list(struct kimage *image,
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unsigned long nr_segments,
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struct kexec_segment __user *segments)
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{
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int ret;
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size_t segment_bytes;
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/* Read in the segments */
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image->nr_segments = nr_segments;
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segment_bytes = nr_segments * sizeof(*segments);
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ret = copy_from_user(image->segment, segments, segment_bytes);
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if (ret)
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ret = -EFAULT;
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return ret;
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}
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static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
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unsigned long nr_segments,
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struct kexec_segment __user *segments,
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unsigned long flags)
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{
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int ret;
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struct kimage *image;
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bool kexec_on_panic = flags & KEXEC_ON_CRASH;
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if (kexec_on_panic) {
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/* Verify we have a valid entry point */
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if ((entry < phys_to_boot_phys(crashk_res.start)) ||
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(entry > phys_to_boot_phys(crashk_res.end)))
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return -EADDRNOTAVAIL;
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}
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/* Allocate and initialize a controlling structure */
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image = do_kimage_alloc_init();
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if (!image)
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return -ENOMEM;
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image->start = entry;
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ret = copy_user_segment_list(image, nr_segments, segments);
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if (ret)
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goto out_free_image;
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if (kexec_on_panic) {
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/* Enable special crash kernel control page alloc policy. */
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image->control_page = crashk_res.start;
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image->type = KEXEC_TYPE_CRASH;
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}
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ret = sanity_check_segment_list(image);
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if (ret)
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goto out_free_image;
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/*
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* Find a location for the control code buffer, and add it
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* the vector of segments so that it's pages will also be
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* counted as destination pages.
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*/
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ret = -ENOMEM;
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image->control_code_page = kimage_alloc_control_pages(image,
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get_order(KEXEC_CONTROL_PAGE_SIZE));
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if (!image->control_code_page) {
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pr_err("Could not allocate control_code_buffer\n");
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goto out_free_image;
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}
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if (!kexec_on_panic) {
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image->swap_page = kimage_alloc_control_pages(image, 0);
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if (!image->swap_page) {
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pr_err("Could not allocate swap buffer\n");
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goto out_free_control_pages;
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}
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}
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*rimage = image;
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return 0;
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out_free_control_pages:
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kimage_free_page_list(&image->control_pages);
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out_free_image:
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kfree(image);
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return ret;
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}
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static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
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struct kexec_segment __user *segments, unsigned long flags)
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{
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struct kimage **dest_image, *image;
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unsigned long i;
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int ret;
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if (flags & KEXEC_ON_CRASH) {
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dest_image = &kexec_crash_image;
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if (kexec_crash_image)
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arch_kexec_unprotect_crashkres();
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} else {
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dest_image = &kexec_image;
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}
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if (nr_segments == 0) {
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/* Uninstall image */
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kimage_free(xchg(dest_image, NULL));
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return 0;
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}
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if (flags & KEXEC_ON_CRASH) {
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/*
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* Loading another kernel to switch to if this one
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* crashes. Free any current crash dump kernel before
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* we corrupt it.
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*/
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kimage_free(xchg(&kexec_crash_image, NULL));
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}
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ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
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if (ret)
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return ret;
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if (flags & KEXEC_PRESERVE_CONTEXT)
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image->preserve_context = 1;
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ret = machine_kexec_prepare(image);
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if (ret)
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goto out;
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for (i = 0; i < nr_segments; i++) {
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ret = kimage_load_segment(image, &image->segment[i]);
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if (ret)
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goto out;
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}
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kimage_terminate(image);
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/* Install the new kernel and uninstall the old */
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image = xchg(dest_image, image);
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out:
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if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
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arch_kexec_protect_crashkres();
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kimage_free(image);
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return ret;
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}
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/*
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* Exec Kernel system call: for obvious reasons only root may call it.
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*
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* This call breaks up into three pieces.
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* - A generic part which loads the new kernel from the current
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* address space, and very carefully places the data in the
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* allocated pages.
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*
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* - A generic part that interacts with the kernel and tells all of
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* the devices to shut down. Preventing on-going dmas, and placing
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* the devices in a consistent state so a later kernel can
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* reinitialize them.
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*
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* - A machine specific part that includes the syscall number
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* and then copies the image to it's final destination. And
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* jumps into the image at entry.
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*
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* kexec does not sync, or unmount filesystems so if you need
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* that to happen you need to do that yourself.
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*/
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SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
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struct kexec_segment __user *, segments, unsigned long, flags)
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{
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int result;
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/* We only trust the superuser with rebooting the system. */
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if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
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return -EPERM;
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/*
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* Verify we have a legal set of flags
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* This leaves us room for future extensions.
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*/
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if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
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return -EINVAL;
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/* Verify we are on the appropriate architecture */
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if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
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((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
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return -EINVAL;
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/* Put an artificial cap on the number
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* of segments passed to kexec_load.
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*/
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if (nr_segments > KEXEC_SEGMENT_MAX)
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return -EINVAL;
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/* Because we write directly to the reserved memory
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* region when loading crash kernels we need a mutex here to
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* prevent multiple crash kernels from attempting to load
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* simultaneously, and to prevent a crash kernel from loading
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* over the top of a in use crash kernel.
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*
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* KISS: always take the mutex.
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*/
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if (!mutex_trylock(&kexec_mutex))
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return -EBUSY;
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result = do_kexec_load(entry, nr_segments, segments, flags);
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mutex_unlock(&kexec_mutex);
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return result;
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}
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#ifdef CONFIG_COMPAT
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COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
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compat_ulong_t, nr_segments,
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struct compat_kexec_segment __user *, segments,
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compat_ulong_t, flags)
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{
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struct compat_kexec_segment in;
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struct kexec_segment out, __user *ksegments;
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unsigned long i, result;
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/* Don't allow clients that don't understand the native
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* architecture to do anything.
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*/
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if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
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return -EINVAL;
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if (nr_segments > KEXEC_SEGMENT_MAX)
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return -EINVAL;
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ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
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for (i = 0; i < nr_segments; i++) {
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result = copy_from_user(&in, &segments[i], sizeof(in));
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if (result)
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return -EFAULT;
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out.buf = compat_ptr(in.buf);
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out.bufsz = in.bufsz;
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out.mem = in.mem;
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out.memsz = in.memsz;
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result = copy_to_user(&ksegments[i], &out, sizeof(out));
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if (result)
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return -EFAULT;
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}
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return sys_kexec_load(entry, nr_segments, ksegments, flags);
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}
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#endif
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