+/*
+ * kexec.c - kexec system call
+ * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
+ * This Edition is maintained by Matthew Veety (aliasxerog) <mveety@gmail.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#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/utsrelease.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/console.h>
+#include <linux/vmalloc.h>
+
+#include <asm/page.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/system.h>
+#include <asm/sections.h>
+#include <asm/unistd.h>
+
+MODULE_LICENSE("GPL");
+
+/* Syscall table */
+void **sys_call_table;
+
+/* original and new reboot syscall */
+asmlinkage long (*original_reboot)(int magic1, int magic2, unsigned int cmd, void __user *arg);
+extern asmlinkage long reboot(int magic1, int magic2, unsigned int cmd, void __user *arg);
+
+/* Per cpu memory for storing cpu states in case of system crash. */
+note_buf_t* crash_notes;
+
+/* vmcoreinfo stuff */
+unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
+u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
+size_t vmcoreinfo_size;
+size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
+
+/* Location of the reserved area for the crash kernel */
+struct resource crashk_res = {
+ .name = "Crash kernel",
+ .start = 0,
+ .end = 0,
+ .flags = IORESOURCE_BUSY | IORESOURCE_MEM
+};
+
+int kexec_should_crash(struct task_struct *p)
+{
+ if (in_interrupt() || !p->pid || is_global_init(p))
+ return 1;
+ return 0;
+}
+
+/*
+ * 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)
+
+static int kimage_is_destination_range(struct kimage *image,
+ unsigned long start, unsigned long end);
+static struct page *kimage_alloc_page(struct kimage *image,
+ gfp_t gfp_mask,
+ unsigned long dest);
+
+static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
+ unsigned long nr_segments,
+ struct kexec_segment __user *segments)
+{
+ size_t segment_bytes;
+ struct kimage *image;
+ unsigned long i;
+ int result;
+
+ /* Allocate a controlling structure */
+ result = -ENOMEM;
+ image = kzalloc(sizeof(*image), GFP_KERNEL);
+ if (!image)
+ goto out;
+
+ image->head = 0;
+ image->entry = &image->head;
+ image->last_entry = &image->head;
+ image->control_page = ~0; /* By default this does not apply */
+ image->start = entry;
+ image->type = KEXEC_TYPE_DEFAULT;
+
+ /* Initialize the list of control pages */
+ INIT_LIST_HEAD(&image->control_pages);
+
+ /* Initialize the list of destination pages */
+ INIT_LIST_HEAD(&image->dest_pages);
+
+ /* Initialize the list of unuseable pages */
+ INIT_LIST_HEAD(&image->unuseable_pages);
+
+ /* Read in the segments */
+ image->nr_segments = nr_segments;
+ segment_bytes = nr_segments * sizeof(*segments);
+ result = copy_from_user(image->segment, segments, segment_bytes);
+ if (result)
+ goto out;
+
+ /*
+ * Verify we have good destination addresses. The caller is
+ * responsible for making certain we don't attempt to load
+ * the new image into invalid or reserved areas of RAM. This
+ * just verifies it is an address we can use.
+ *
+ * Since the kernel does everything in page size chunks ensure
+ * the destination addreses are page aligned. Too many
+ * special cases crop of when we don't do this. The most
+ * insidious is getting overlapping destination addresses
+ * simply because addresses are changed to page size
+ * granularity.
+ */
+ result = -EADDRNOTAVAIL;
+ for (i = 0; i < nr_segments; i++) {
+ unsigned long mstart, mend;
+
+ mstart = image->segment[i].mem;
+ mend = mstart + image->segment[i].memsz;
+ if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
+ goto out;
+ if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
+ goto out;
+ }
+
+ /* Verify our destination addresses do not overlap.
+ * If we alloed overlapping destination addresses
+ * through very weird things can happen with no
+ * easy explanation as one segment stops on another.
+ */
+ result = -EINVAL;
+ for (i = 0; i < nr_segments; i++) {
+ unsigned long mstart, mend;
+ unsigned long j;
+
+ mstart = image->segment[i].mem;
+ mend = mstart + image->segment[i].memsz;
+ for (j = 0; j < i; j++) {
+ unsigned long pstart, pend;
+ pstart = image->segment[j].mem;
+ pend = pstart + image->segment[j].memsz;
+ /* Do the segments overlap ? */
+ if ((mend > pstart) && (mstart < pend))
+ goto out;
+ }
+ }
+
+ /* Ensure our buffer sizes are strictly less than
+ * our memory sizes. This should always be the case,
+ * and it is easier to check up front than to be surprised
+ * later on.
+ */
+ result = -EINVAL;
+ for (i = 0; i < nr_segments; i++) {
+ if (image->segment[i].bufsz > image->segment[i].memsz)
+ goto out;
+ }
+
+ result = 0;
+out:
+ if (result == 0)
+ *rimage = image;
+ else
+ kfree(image);
+
+ return result;
+
+}
+
+static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
+ unsigned long nr_segments,
+ struct kexec_segment __user *segments)
+{
+ int result;
+ struct kimage *image;
+
+ /* Allocate and initialize a controlling structure */
+ image = NULL;
+ result = do_kimage_alloc(&image, entry, nr_segments, segments);
+ if (result)
+ goto out;
+
+ *rimage = image;
+
+ /*
+ * Find a location for the control code buffer, and add it
+ * the vector of segments so that it's pages will also be
+ * counted as destination pages.
+ */
+ result = -ENOMEM;
+ image->control_code_page = kimage_alloc_control_pages(image,
+ get_order(KEXEC_CONTROL_PAGE_SIZE));
+ if (!image->control_code_page) {
+ printk(KERN_ERR "Could not allocate control_code_buffer\n");
+ goto out;
+ }
+
+ image->swap_page = kimage_alloc_control_pages(image, 0);
+ if (!image->swap_page) {
+ printk(KERN_ERR "Could not allocate swap buffer\n");
+ goto out;
+ }
+
+ result = 0;
+ out:
+ if (result == 0)
+ *rimage = image;
+ else
+ kfree(image);
+
+ return result;
+}
+
+static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
+ unsigned long nr_segments,
+ struct kexec_segment __user *segments)
+{
+ int result;
+ struct kimage *image;
+ unsigned long i;
+
+ image = NULL;
+ /* Verify we have a valid entry point */
+ if ((entry < crashk_res.start) || (entry > crashk_res.end)) {
+ result = -EADDRNOTAVAIL;
+ goto out;
+ }
+
+ /* Allocate and initialize a controlling structure */
+ result = do_kimage_alloc(&image, entry, nr_segments, segments);
+ if (result)
+ goto out;
+
+ /* Enable the special crash kernel control page
+ * allocation policy.
+ */
+ image->control_page = crashk_res.start;
+ image->type = KEXEC_TYPE_CRASH;
+
+ /*
+ * Verify we have good destination addresses. Normally
+ * the caller is responsible for making certain we don't
+ * attempt to load the new image into invalid or reserved
+ * areas of RAM. But crash kernels are preloaded into a
+ * reserved area of ram. We must ensure the addresses
+ * are in the reserved area otherwise preloading the
+ * kernel could corrupt things.
+ */
+ result = -EADDRNOTAVAIL;
+ for (i = 0; i < nr_segments; i++) {
+ unsigned long mstart, mend;
+
+ mstart = image->segment[i].mem;
+ mend = mstart + image->segment[i].memsz - 1;
+ /* Ensure we are within the crash kernel limits */
+ if ((mstart < crashk_res.start) || (mend > crashk_res.end))
+ goto out;
+ }
+
+ /*
+ * Find a location for the control code buffer, and add
+ * the vector of segments so that it's pages will also be
+ * counted as destination pages.
+ */
+ result = -ENOMEM;
+ image->control_code_page = kimage_alloc_control_pages(image,
+ get_order(KEXEC_CONTROL_PAGE_SIZE));
+ if (!image->control_code_page) {
+ printk(KERN_ERR "Could not allocate control_code_buffer\n");
+ goto out;
+ }
+
+ result = 0;
+out:
+ if (result == 0)
+ *rimage = image;
+ else
+ kfree(image);
+
+ return result;
+}
+
+static int kimage_is_destination_range(struct kimage *image,
+ unsigned long start,
+ unsigned long end)
+{
+ unsigned long i;
+
+ for (i = 0; i < image->nr_segments; i++) {
+ unsigned long mstart, mend;
+
+ mstart = image->segment[i].mem;
+ mend = mstart + image->segment[i].memsz;
+ if ((end > mstart) && (start < mend))
+ return 1;
+ }
+
+ return 0;
+}
+
+static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+ struct page *pages;
+
+ pages = alloc_pages(gfp_mask, order);
+ if (pages) {
+ unsigned int count, i;
+ pages->mapping = NULL;
+ set_page_private(pages, order);
+ count = 1 << order;
+ for (i = 0; i < count; i++)
+ SetPageReserved(pages + i);
+ }
+
+ return pages;
+}
+
+static void kimage_free_pages(struct page *page)
+{
+ unsigned int order, count, i;
+
+ order = page_private(page);
+ count = 1 << order;
+ for (i = 0; i < count; i++)
+ ClearPageReserved(page + i);
+ __free_pages(page, order);
+}
+
+static void kimage_free_page_list(struct list_head *list)
+{
+ struct list_head *pos, *next;
+
+ list_for_each_safe(pos, next, list) {
+ struct page *page;
+
+ page = list_entry(pos, struct page, lru);
+ list_del(&page->lru);
+ kimage_free_pages(page);
+ }
+}
+
+static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
+ unsigned int order)
+{
+ /* Control pages are special, they are the intermediaries
+ * that are needed while we copy the rest of the pages
+ * to their final resting place. As such they must
+ * not conflict with either the destination addresses
+ * or memory the kernel is already using.
+ *
+ * The only case where we really need more than one of
+ * these are for architectures where we cannot disable
+ * the MMU and must instead generate an identity mapped
+ * page table for all of the memory.
+ *
+ * At worst this runs in O(N) of the image size.
+ */
+ struct list_head extra_pages;
+ struct page *pages;
+ unsigned int count;
+
+ count = 1 << order;
+ INIT_LIST_HEAD(&extra_pages);
+
+ /* Loop while I can allocate a page and the page allocated
+ * is a destination page.
+ */
+ do {
+ unsigned long pfn, epfn, addr, eaddr;
+
+ pages = kimage_alloc_pages(GFP_KERNEL, order);
+ if (!pages)
+ break;
+ pfn = page_to_pfn(pages);
+ epfn = pfn + count;
+ addr = pfn << PAGE_SHIFT;
+ eaddr = epfn << PAGE_SHIFT;
+ if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
+ kimage_is_destination_range(image, addr, eaddr)) {
+ list_add(&pages->lru, &extra_pages);
+ pages = NULL;
+ }
+ } while (!pages);
+
+ if (pages) {
+ /* Remember the allocated page... */
+ list_add(&pages->lru, &image->control_pages);
+
+ /* Because the page is already in it's destination
+ * location we will never allocate another page at
+ * that address. Therefore kimage_alloc_pages
+ * will not return it (again) and we don't need
+ * to give it an entry in image->segment[].
+ */
+ }
+ /* Deal with the destination pages I have inadvertently allocated.
+ *
+ * Ideally I would convert multi-page allocations into single
+ * page allocations, and add everyting to image->dest_pages.
+ *
+ * For now it is simpler to just free the pages.
+ */
+ kimage_free_page_list(&extra_pages);
+
+ return pages;
+}
+
+static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
+ unsigned int order)
+{
+ /* Control pages are special, they are the intermediaries
+ * that are needed while we copy the rest of the pages
+ * to their final resting place. As such they must
+ * not conflict with either the destination addresses
+ * or memory the kernel is already using.
+ *
+ * Control pages are also the only pags we must allocate
+ * when loading a crash kernel. All of the other pages
+ * are specified by the segments and we just memcpy
+ * into them directly.
+ *
+ * The only case where we really need more than one of
+ * these are for architectures where we cannot disable
+ * the MMU and must instead generate an identity mapped
+ * page table for all of the memory.
+ *
+ * Given the low demand this implements a very simple
+ * allocator that finds the first hole of the appropriate
+ * size in the reserved memory region, and allocates all
+ * of the memory up to and including the hole.
+ */
+ unsigned long hole_start, hole_end, size;
+ struct page *pages;
+
+ pages = NULL;
+ size = (1 << order) << PAGE_SHIFT;
+ hole_start = (image->control_page + (size - 1)) & ~(size - 1);
+ hole_end = hole_start + size - 1;
+ while (hole_end <= crashk_res.end) {
+ unsigned long i;
+
+ if (hole_end > KEXEC_CONTROL_MEMORY_LIMIT)
+ break;
+ if (hole_end > crashk_res.end)
+ break;
+ /* See if I overlap any of the segments */
+ for (i = 0; i < image->nr_segments; i++) {
+ unsigned long mstart, mend;
+
+ mstart = image->segment[i].mem;
+ mend = mstart + image->segment[i].memsz - 1;
+ if ((hole_end >= mstart) && (hole_start <= mend)) {
+ /* Advance the hole to the end of the segment */
+ hole_start = (mend + (size - 1)) & ~(size - 1);
+ hole_end = hole_start + size - 1;
+ break;
+ }
+ }
+ /* If I don't overlap any segments I have found my hole! */
+ if (i == image->nr_segments) {
+ pages = pfn_to_page(hole_start >> PAGE_SHIFT);
+ break;
+ }
+ }
+ if (pages)
+ image->control_page = hole_end;
+
+ return pages;
+}
+
+
+struct page *kimage_alloc_control_pages(struct kimage *image,
+ unsigned int order)
+{
+ struct page *pages = NULL;
+
+ switch (image->type) {
+ case KEXEC_TYPE_DEFAULT:
+ pages = kimage_alloc_normal_control_pages(image, order);
+ break;
+ case KEXEC_TYPE_CRASH:
+ pages = kimage_alloc_crash_control_pages(image, order);
+ break;
+ }
+
+ return pages;
+}
+
+static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
+{
+ if (*image->entry != 0)
+ image->entry++;
+
+ if (image->entry == image->last_entry) {
+ kimage_entry_t *ind_page;
+ struct page *page;
+
+ page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
+ if (!page)
+ return -ENOMEM;
+
+ ind_page = page_address(page);
+ *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
+ image->entry = ind_page;
+ image->last_entry = ind_page +
+ ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
+ }
+ *image->entry = entry;
+ image->entry++;
+ *image->entry = 0;
+
+ return 0;
+}
+
+static int kimage_set_destination(struct kimage *image,
+ unsigned long destination)
+{
+ int result;
+
+ destination &= PAGE_MASK;
+ result = kimage_add_entry(image, destination | IND_DESTINATION);
+ if (result == 0)
+ image->destination = destination;
+
+ return result;
+}
+
+
+static int kimage_add_page(struct kimage *image, unsigned long page)
+{
+ int result;
+
+ page &= PAGE_MASK;
+ result = kimage_add_entry(image, page | IND_SOURCE);
+ if (result == 0)
+ image->destination += PAGE_SIZE;
+
+ return result;
+}
+
+
+static void kimage_free_extra_pages(struct kimage *image)
+{
+ /* Walk through and free any extra destination pages I may have */
+ kimage_free_page_list(&image->dest_pages);
+
+ /* Walk through and free any unuseable pages I have cached */
+ kimage_free_page_list(&image->unuseable_pages);
+
+}
+static void kimage_terminate(struct kimage *image)
+{
+ if (*image->entry != 0)
+ image->entry++;
+
+ *image->entry = IND_DONE;
+}
+
+#define for_each_kimage_entry(image, ptr, entry) \
+ for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
+ ptr = (entry & IND_INDIRECTION)? \
+ phys_to_virt((entry & PAGE_MASK)): ptr +1)
+
+static void kimage_free_entry(kimage_entry_t entry)
+{
+ struct page *page;
+
+ page = pfn_to_page(entry >> PAGE_SHIFT);
+ kimage_free_pages(page);
+}
+
+static void kimage_free(struct kimage *image)
+{
+ kimage_entry_t *ptr, entry;
+ kimage_entry_t ind = 0;
+
+ if (!image)
+ return;
+
+ kimage_free_extra_pages(image);
+ for_each_kimage_entry(image, ptr, entry) {
+ if (entry & IND_INDIRECTION) {
+ /* Free the previous indirection page */
+ if (ind & IND_INDIRECTION)
+ kimage_free_entry(ind);
+ /* Save this indirection page until we are
+ * done with it.
+ */
+ ind = entry;
+ }
+ else if (entry & IND_SOURCE)
+ kimage_free_entry(entry);
+ }
+ /* Free the final indirection page */
+ if (ind & IND_INDIRECTION)
+ kimage_free_entry(ind);
+
+ /* Handle any machine specific cleanup */
+ machine_kexec_cleanup(image);
+
+ /* Free the kexec control pages... */
+ kimage_free_page_list(&image->control_pages);
+ kfree(image);
+}
+
+static kimage_entry_t *kimage_dst_used(struct kimage *image,
+ unsigned long page)
+{
+ kimage_entry_t *ptr, entry;
+ unsigned long destination = 0;
+
+ for_each_kimage_entry(image, ptr, entry) {
+ if (entry & IND_DESTINATION)
+ destination = entry & PAGE_MASK;
+ else if (entry & IND_SOURCE) {
+ if (page == destination)
+ return ptr;
+ destination += PAGE_SIZE;
+ }
+ }
+
+ return NULL;
+}
+
+static struct page *kimage_alloc_page(struct kimage *image,
+ gfp_t gfp_mask,
+ unsigned long destination)
+{
+ /*
+ * Here we implement safeguards to ensure that a source page
+ * is not copied to its destination page before the data on
+ * the destination page is no longer useful.
+ *
+ * To do this we maintain the invariant that a source page is
+ * either its own destination page, or it is not a
+ * destination page at all.
+ *
+ * That is slightly stronger than required, but the proof
+ * that no problems will not occur is trivial, and the
+ * implementation is simply to verify.
+ *
+ * When allocating all pages normally this algorithm will run
+ * in O(N) time, but in the worst case it will run in O(N^2)
+ * time. If the runtime is a problem the data structures can
+ * be fixed.
+ */
+ struct page *page;
+ unsigned long addr;
+
+ /*
+ * Walk through the list of destination pages, and see if I
+ * have a match.
+ */
+ list_for_each_entry(page, &image->dest_pages, lru) {
+ addr = page_to_pfn(page) << PAGE_SHIFT;
+ if (addr == destination) {
+ list_del(&page->lru);
+ return page;
+ }
+ }
+ page = NULL;
+ while (1) {
+ kimage_entry_t *old;
+
+ /* Allocate a page, if we run out of memory give up */
+ page = kimage_alloc_pages(gfp_mask, 0);
+ if (!page)
+ return NULL;
+ /* If the page cannot be used file it away */
+ if (page_to_pfn(page) >
+ (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
+ list_add(&page->lru, &image->unuseable_pages);
+ continue;
+ }
+ addr = page_to_pfn(page) << PAGE_SHIFT;
+
+ /* If it is the destination page we want use it */
+ if (addr == destination)
+ break;
+
+ /* If the page is not a destination page use it */
+ if (!kimage_is_destination_range(image, addr,
+ addr + PAGE_SIZE))
+ break;
+
+ /*
+ * I know that the page is someones destination page.
+ * See if there is already a source page for this
+ * destination page. And if so swap the source pages.
+ */
+ old = kimage_dst_used(image, addr);
+ if (old) {
+ /* If so move it */
+ unsigned long old_addr;
+ struct page *old_page;
+
+ old_addr = *old & PAGE_MASK;
+ old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
+ copy_highpage(page, old_page);
+ *old = addr | (*old & ~PAGE_MASK);
+
+ /* The old page I have found cannot be a
+ * destination page, so return it if it's
+ * gfp_flags honor the ones passed in.
+ */
+ if (!(gfp_mask & __GFP_HIGHMEM) &&
+ PageHighMem(old_page)) {
+ kimage_free_pages(old_page);
+ continue;
+ }
+ addr = old_addr;
+ page = old_page;
+ break;
+ }
+ else {
+ /* Place the page on the destination list I
+ * will use it later.
+ */
+ list_add(&page->lru, &image->dest_pages);
+ }
+ }
+
+ return page;
+}
+
+static int kimage_load_normal_segment(struct kimage *image,
+ struct kexec_segment *segment)
+{
+ unsigned long maddr;
+ unsigned long ubytes, mbytes;
+ int result;
+ unsigned char __user *buf;
+
+ result = 0;
+ buf = segment->buf;
+ ubytes = segment->bufsz;
+ mbytes = segment->memsz;
+ maddr = segment->mem;
+
+ result = kimage_set_destination(image, maddr);
+ if (result < 0)
+ goto out;
+
+ while (mbytes) {
+ struct page *page;
+ char *ptr;
+ size_t uchunk, mchunk;
+
+ page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
+ if (!page) {
+ result = -ENOMEM;
+ goto out;
+ }
+ result = kimage_add_page(image, page_to_pfn(page)
+ << PAGE_SHIFT);
+ if (result < 0)
+ goto out;
+
+ ptr = kmap(page);
+ /* Start with a clear page */
+ memset(ptr, 0, PAGE_SIZE);
+ ptr += maddr & ~PAGE_MASK;
+ mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
+ if (mchunk > mbytes)
+ mchunk = mbytes;
+
+ uchunk = mchunk;
+ if (uchunk > ubytes)
+ uchunk = ubytes;
+
+ result = copy_from_user(ptr, buf, uchunk);
+ kunmap(page);
+ if (result) {
+ result = (result < 0) ? result : -EIO;
+ goto out;
+ }
+ ubytes -= uchunk;
+ maddr += mchunk;
+ buf += mchunk;
+ mbytes -= mchunk;
+ }
+out:
+ return result;
+}
+
+static int kimage_load_crash_segment(struct kimage *image,
+ struct kexec_segment *segment)
+{
+ /* For crash dumps kernels we simply copy the data from
+ * user space to it's destination.
+ * We do things a page at a time for the sake of kmap.
+ */
+ unsigned long maddr;
+ unsigned long ubytes, mbytes;
+ int result;
+ unsigned char __user *buf;
+
+ result = 0;
+ buf = segment->buf;
+ ubytes = segment->bufsz;
+ mbytes = segment->memsz;
+ maddr = segment->mem;
+ while (mbytes) {
+ struct page *page;
+ char *ptr;
+ size_t uchunk, mchunk;
+
+ page = pfn_to_page(maddr >> PAGE_SHIFT);
+ if (!page) {
+ result = -ENOMEM;
+ goto out;
+ }
+ ptr = kmap(page);
+ ptr += maddr & ~PAGE_MASK;
+ mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
+ if (mchunk > mbytes)
+ mchunk = mbytes;
+
+ uchunk = mchunk;
+ if (uchunk > ubytes) {
+ uchunk = ubytes;
+ /* Zero the trailing part of the page */
+ memset(ptr + uchunk, 0, mchunk - uchunk);
+ }
+ result = copy_from_user(ptr, buf, uchunk);
+ kexec_flush_icache_page(page);
+ kunmap(page);
+ if (result) {
+ result = (result < 0) ? result : -EIO;
+ goto out;
+ }
+ ubytes -= uchunk;
+ maddr += mchunk;
+ buf += mchunk;
+ mbytes -= mchunk;
+ }
+out:
+ return result;
+}
+
+static int kimage_load_segment(struct kimage *image,
+ struct kexec_segment *segment)
+{
+ int result = -ENOMEM;
+
+ switch (image->type) {
+ case KEXEC_TYPE_DEFAULT:
+ result = kimage_load_normal_segment(image, segment);
+ break;
+ case KEXEC_TYPE_CRASH:
+ result = kimage_load_crash_segment(image, segment);
+ break;
+ }
+
+ return result;
+}
+
+/*
+ * Exec Kernel system call: for obvious reasons only root may call it.
+ *
+ * This call breaks up into three pieces.
+ * - A generic part which loads the new kernel from the current
+ * address space, and very carefully places the data in the
+ * allocated pages.
+ *
+ * - A generic part that interacts with the kernel and tells all of
+ * the devices to shut down. Preventing on-going dmas, and placing
+ * the devices in a consistent state so a later kernel can
+ * reinitialize them.
+ *
+ * - A machine specific part that includes the syscall number
+ * and the copies the image to it's final destination. And
+ * jumps into the image at entry.
+ *
+ * kexec does not sync, or unmount filesystems so if you need
+ * that to happen you need to do that yourself.
+ */
+struct kimage *kexec_image;
+struct kimage *kexec_crash_image;
+
+static DEFINE_MUTEX(kexec_mutex);
+
+asmlinkage long kexec_load(unsigned long entry, unsigned long nr_segments, struct kexec_segment __user *segments, unsigned long flags)
+{
+ struct kimage **dest_image, *image;
+ int result;
+
+ /* We only trust the superuser with rebooting the system. */
+ if (!capable(CAP_SYS_BOOT))
+ return -EPERM;
+
+ /*
+ * Verify we have a legal set of flags
+ * This leaves us room for future extensions.
+ */
+ if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
+ return -EINVAL;
+
+ /* Verify we are on the appropriate architecture */
+ if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
+ ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
+ return -EINVAL;
+
+ /* Put an artificial cap on the number
+ * of segments passed to kexec_load.
+ */
+ if (nr_segments > KEXEC_SEGMENT_MAX)
+ return -EINVAL;
+
+ image = NULL;
+ result = 0;
+
+ /* Because we write directly to the reserved memory
+ * region when loading crash kernels we need a mutex here to
+ * prevent multiple crash kernels from attempting to load
+ * simultaneously, and to prevent a crash kernel from loading
+ * over the top of a in use crash kernel.
+ *
+ * KISS: always take the mutex.
+ */
+ if (!mutex_trylock(&kexec_mutex))
+ return -EBUSY;
+
+ dest_image = &kexec_image;
+ if (flags & KEXEC_ON_CRASH)
+ dest_image = &kexec_crash_image;
+ if (nr_segments > 0) {
+ unsigned long i;
+
+ /* Loading another kernel to reboot into */
+ if ((flags & KEXEC_ON_CRASH) == 0)
+ result = kimage_normal_alloc(&image, entry,
+ nr_segments, segments);
+ /* Loading another kernel to switch to if this one crashes */
+ else if (flags & KEXEC_ON_CRASH) {
+ /* Free any current crash dump kernel before
+ * we corrupt it.
+ */
+ kimage_free(xchg(&kexec_crash_image, NULL));
+ result = kimage_crash_alloc(&image, entry,
+ nr_segments, segments);
+ }
+ if (result)
+ goto out;
+
+ if (flags & KEXEC_PRESERVE_CONTEXT)
+ image->preserve_context = 1;
+ result = machine_kexec_prepare(image);
+ if (result)
+ goto out;
+
+ for (i = 0; i < nr_segments; i++) {
+ result = kimage_load_segment(image, &image->segment[i]);
+ if (result)
+ goto out;
+ }
+ kimage_terminate(image);
+ }
+ /* Install the new kernel, and Uninstall the old */
+ image = xchg(dest_image, image);
+
+out:
+ mutex_unlock(&kexec_mutex);
+ kimage_free(image);
+
+ return result;
+}
+
+#ifdef CONFIG_COMPAT
+asmlinkage long compat_sys_kexec_load(unsigned long entry,
+ unsigned long nr_segments,
+ struct compat_kexec_segment __user *segments,
+ unsigned long flags)
+{
+ struct compat_kexec_segment in;
+ struct kexec_segment out, __user *ksegments;
+ unsigned long i, result;
+
+ /* Don't allow clients that don't understand the native
+ * architecture to do anything.
+ */
+ if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
+ return -EINVAL;
+
+ if (nr_segments > KEXEC_SEGMENT_MAX)
+ return -EINVAL;
+
+ ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
+ for (i=0; i < nr_segments; i++) {
+ result = copy_from_user(&in, &segments[i], sizeof(in));
+ if (result)
+ return -EFAULT;
+
+ out.buf = compat_ptr(in.buf);
+ out.bufsz = in.bufsz;
+ out.mem = in.mem;
+ out.memsz = in.memsz;
+
+ result = copy_to_user(&ksegments[i], &out, sizeof(out));
+ if (result)
+ return -EFAULT;
+ }
+
+ return sys_kexec_load(entry, nr_segments, ksegments, flags);
+}
+#endif
+
+void crash_kexec(struct pt_regs *regs)
+{
+ /* Take the kexec_mutex here to prevent sys_kexec_load
+ * running on one cpu from replacing the crash kernel
+ * we are using after a panic on a different cpu.
+ *
+ * If the crash kernel was not located in a fixed area
+ * of memory the xchg(&kexec_crash_image) would be
+ * sufficient. But since I reuse the memory...
+ */
+ if (mutex_trylock(&kexec_mutex)) {
+ if (kexec_crash_image) {
+ struct pt_regs fixed_regs;
+ crash_setup_regs(&fixed_regs, regs);
+ crash_save_vmcoreinfo();
+ machine_crash_shutdown(&fixed_regs);
+ machine_kexec(kexec_crash_image);
+ }
+ mutex_unlock(&kexec_mutex);
+ }
+}
+
+static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
+ size_t data_len)
+{
+ struct elf_note note;
+
+ note.n_namesz = strlen(name) + 1;
+ note.n_descsz = data_len;
+ note.n_type = type;
+ memcpy(buf, ¬e, sizeof(note));
+ buf += (sizeof(note) + 3)/4;
+ memcpy(buf, name, note.n_namesz);
+ buf += (note.n_namesz + 3)/4;
+ memcpy(buf, data, note.n_descsz);
+ buf += (note.n_descsz + 3)/4;
+
+ return buf;
+}
+
+static void final_note(u32 *buf)
+{
+ struct elf_note note;
+
+ note.n_namesz = 0;
+ note.n_descsz = 0;
+ note.n_type = 0;
+ memcpy(buf, ¬e, sizeof(note));
+}
+
+void crash_save_cpu(struct pt_regs *regs, int cpu)
+{
+ struct elf_prstatus prstatus;
+ u32 *buf;
+
+ if ((cpu < 0) || (cpu >= nr_cpu_ids))
+ return;
+
+ /* Using ELF notes here is opportunistic.
+ * I need a well defined structure format
+ * for the data I pass, and I need tags
+ * on the data to indicate what information I have
+ * squirrelled away. ELF notes happen to provide
+ * all of that, so there is no need to invent something new.
+ */
+ buf = (u32*)per_cpu_ptr(crash_notes, cpu);
+ if (!buf)
+ return;
+ memset(&prstatus, 0, sizeof(prstatus));
+ prstatus.pr_pid = current->pid;
+ elf_core_copy_regs(&prstatus.pr_reg, regs);
+ buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
+ &prstatus, sizeof(prstatus));
+ final_note(buf);
+}
+
+/*
+ * parsing the "crashkernel" commandline
+ *
+ * this code is intended to be called from architecture specific code
+ */
+
+
+/*
+ * This function parses command lines in the format
+ *
+ * crashkernel=ramsize-range:size[,...][@offset]
+ *
+ * The function returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_mem(char *cmdline,
+ unsigned long long system_ram,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base)
+{
+ char *cur = cmdline, *tmp;
+
+ /* for each entry of the comma-separated list */
+ do {
+ unsigned long long start, end = ULLONG_MAX, size;
+
+ /* get the start of the range */
+ start = memparse(cur, &tmp);
+ if (cur == tmp) {
+ pr_warning("crashkernel: Memory value expected\n");
+ return -EINVAL;
+ }
+ cur = tmp;
+ if (*cur != '-') {
+ pr_warning("crashkernel: '-' expected\n");
+ return -EINVAL;
+ }
+ cur++;
+
+ /* if no ':' is here, than we read the end */
+ if (*cur != ':') {
+ end = memparse(cur, &tmp);
+ if (cur == tmp) {
+ pr_warning("crashkernel: Memory "
+ "value expected\n");
+ return -EINVAL;
+ }
+ cur = tmp;
+ if (end <= start) {
+ pr_warning("crashkernel: end <= start\n");
+ return -EINVAL;
+ }
+ }
+
+ if (*cur != ':') {
+ pr_warning("crashkernel: ':' expected\n");
+ return -EINVAL;
+ }
+ cur++;
+
+ size = memparse(cur, &tmp);
+ if (cur == tmp) {
+ pr_warning("Memory value expected\n");
+ return -EINVAL;
+ }
+ cur = tmp;
+ if (size >= system_ram) {
+ pr_warning("crashkernel: invalid size\n");
+ return -EINVAL;
+ }
+
+ /* match ? */
+ if (system_ram >= start && system_ram < end) {
+ *crash_size = size;
+ break;
+ }
+ } while (*cur++ == ',');
+
+ if (*crash_size > 0) {
+ while (*cur != ' ' && *cur != '@')
+ cur++;
+ if (*cur == '@') {
+ cur++;
+ *crash_base = memparse(cur, &tmp);
+ if (cur == tmp) {
+ pr_warning("Memory value expected "
+ "after '@'\n");
+ return -EINVAL;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * That function parses "simple" (old) crashkernel command lines like
+ *
+ * crashkernel=size[@offset]
+ *
+ * It returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_simple(char *cmdline,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base)
+{
+ char *cur = cmdline;
+
+ *crash_size = memparse(cmdline, &cur);
+ if (cmdline == cur) {
+ pr_warning("crashkernel: memory value expected\n");
+ return -EINVAL;
+ }
+
+ if (*cur == '@')
+ *crash_base = memparse(cur+1, &cur);
+
+ return 0;
+}
+
+/*
+ * That function is the entry point for command line parsing and should be
+ * called from the arch-specific code.
+ */
+int __init parse_crashkernel(char *cmdline,
+ unsigned long long system_ram,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base)
+{
+ char *p = cmdline, *ck_cmdline = NULL;
+ char *first_colon, *first_space;
+
+ BUG_ON(!crash_size || !crash_base);
+ *crash_size = 0;
+ *crash_base = 0;
+
+ /* find crashkernel and use the last one if there are more */
+ p = strstr(p, "crashkernel=");
+ while (p) {
+ ck_cmdline = p;
+ p = strstr(p+1, "crashkernel=");
+ }
+
+ if (!ck_cmdline)
+ return -EINVAL;
+
+ ck_cmdline += 12; /* strlen("crashkernel=") */
+
+ /*
+ * if the commandline contains a ':', then that's the extended
+ * syntax -- if not, it must be the classic syntax
+ */
+ first_colon = strchr(ck_cmdline, ':');
+ first_space = strchr(ck_cmdline, ' ');
+ if (first_colon && (!first_space || first_colon < first_space))
+ return parse_crashkernel_mem(ck_cmdline, system_ram,
+ crash_size, crash_base);
+ else
+ return parse_crashkernel_simple(ck_cmdline, crash_size,
+ crash_base);
+
+ return 0;
+}
+
+
+
+void crash_save_vmcoreinfo(void)
+{
+ u32 *buf;
+
+ if (!vmcoreinfo_size)
+ return;
+
+ vmcoreinfo_append_str("CRASHTIME=%ld", get_seconds());
+
+ buf = (u32 *)vmcoreinfo_note;
+
+ buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
+ vmcoreinfo_size);
+
+ final_note(buf);
+}
+
+void vmcoreinfo_append_str(const char *fmt, ...)
+{
+ va_list args;
+ char buf[0x50];
+ int r;
+
+ va_start(args, fmt);
+ r = vsnprintf(buf, sizeof(buf), fmt, args);
+ va_end(args);
+
+ if (r + vmcoreinfo_size > vmcoreinfo_max_size)
+ r = vmcoreinfo_max_size - vmcoreinfo_size;
+
+ memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
+
+ vmcoreinfo_size += r;
+}
+
+/*
+ * provide an empty default implementation here -- architecture
+ * code may override this
+ */
+void __attribute__ ((weak)) arch_crash_save_vmcoreinfo(void)
+{}
+
+unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
+{
+ return __pa((unsigned long)(char *)&vmcoreinfo_note);
+}
+
+/*
+ * Move into place and start executing a preloaded standalone
+ * executable. If nothing was preloaded return an error.
+ */
+int kernel_kexec(void)
+{
+ int error = 0;
+
+ if (!mutex_trylock(&kexec_mutex))
+ return -EBUSY;
+ if (!kexec_image) {
+ error = -EINVAL;
+ goto Unlock;
+ }
+
+#ifdef CONFIG_KEXEC_JUMP
+ if (kexec_image->preserve_context) {
+ mutex_lock(&pm_mutex);
+ pm_prepare_console();
+ error = freeze_processes();
+ if (error) {
+ error = -EBUSY;
+ goto Restore_console;
+ }
+ suspend_console();
+ error = device_suspend(PMSG_FREEZE);
+ if (error)
+ goto Resume_console;
+ error = disable_nonboot_cpus();
+ if (error)
+ goto Resume_devices;
+ device_pm_lock();
+ local_irq_disable();
+ /* At this point, device_suspend() has been called,
+ * but *not* device_power_down(). We *must*
+ * device_power_down() now. Otherwise, drivers for
+ * some devices (e.g. interrupt controllers) become
+ * desynchronized with the actual state of the
+ * hardware at resume time, and evil weirdness ensues.
+ */
+ error = device_power_down(PMSG_FREEZE);
+ if (error)
+ goto Enable_irqs;
+
+ /* Suspend system devices */
+ error = sysdev_suspend(PMSG_FREEZE);
+ if (error)
+ goto Power_up_devices;
+ } else
+#endif
+ {
+ kernel_restart_prepare(NULL);
+ printk(KERN_EMERG "Starting new kernel\n");
+ machine_shutdown();
+ }
+
+ machine_kexec(kexec_image);
+
+#ifdef CONFIG_KEXEC_JUMP
+ if (kexec_image->preserve_context) {
+ sysdev_resume();
+ Power_up_devices:
+ device_power_up(PMSG_RESTORE);
+ Enable_irqs:
+ local_irq_enable();
+ device_pm_unlock();
+ enable_nonboot_cpus();
+ Resume_devices:
+ device_resume(PMSG_RESTORE);
+ Resume_console:
+ resume_console();
+ thaw_processes();
+ Restore_console:
+ pm_restore_console();
+ mutex_unlock(&pm_mutex);
+ }
+#endif
+
+ Unlock:
+ mutex_unlock(&kexec_mutex);
+ return error;
+}
+
+unsigned long **find_sys_call_table(void) {
+ unsigned long **sctable;
+ unsigned long ptr;
+ extern int loops_per_jiffy;
+ sctable = NULL;
+ for (ptr = (unsigned long)&unlock_kernel; ptr < (unsigned long)&loops_per_jiffy; ptr += sizeof(void *)) {
+ unsigned long *p;
+ p = (unsigned long *)ptr;
+ if (p[__NR_close] == (unsigned long) sys_close) {
+ sctable = (unsigned long **)p;
+ return &sctable[0];
+ }
+ }
+ return NULL;
+}
+
+static int __init kexec_module_init(void)
+{
+// sys_call_table=(void **)find_sys_call_table();
+// if(sys_call_table==NULL) {
+// printk(KERN_ERR "Cannot find the system call address\n");
+// return -1; // do not load
+// }
+
+ sys_call_table=(void **)0xc003d004;
+
+ /* Set kexec_load() syscall. */
+ sys_call_table[__NR_kexec_load]=kexec_load;
+
+ /* Swap reboot() syscall and store original */
+ original_reboot=sys_call_table[__NR_reboot];
+ sys_call_table[__NR_reboot]=reboot;
+
+ /* crash_notes_memory_init */
+ /* Allocate memory for saving cpu registers. */
+ crash_notes = alloc_percpu(note_buf_t);
+ if (!crash_notes) {
+ printk("Kexec: Memory allocation for saving cpu register"
+ " states failed\n");
+ return -ENOMEM;
+ }
+
+ /* crash_vmcoreinfo_init */
+ VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
+ VMCOREINFO_PAGESIZE(PAGE_SIZE);
+
+ VMCOREINFO_SYMBOL(init_uts_ns);
+ VMCOREINFO_SYMBOL(node_online_map);
+
+#ifndef CONFIG_NEED_MULTIPLE_NODES
+ VMCOREINFO_SYMBOL(mem_map);
+ VMCOREINFO_SYMBOL(contig_page_data);
+#endif
+#ifdef CONFIG_SPARSEMEM
+ VMCOREINFO_SYMBOL(mem_section);
+ VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
+ VMCOREINFO_STRUCT_SIZE(mem_section);
+ VMCOREINFO_OFFSET(mem_section, section_mem_map);
+#endif
+ VMCOREINFO_STRUCT_SIZE(page);
+ VMCOREINFO_STRUCT_SIZE(pglist_data);
+ VMCOREINFO_STRUCT_SIZE(zone);
+ VMCOREINFO_STRUCT_SIZE(free_area);
+ VMCOREINFO_STRUCT_SIZE(list_head);
+ VMCOREINFO_SIZE(nodemask_t);
+ VMCOREINFO_OFFSET(page, flags);
+ VMCOREINFO_OFFSET(page, _count);
+ VMCOREINFO_OFFSET(page, mapping);
+ VMCOREINFO_OFFSET(page, lru);
+ VMCOREINFO_OFFSET(pglist_data, node_zones);
+ VMCOREINFO_OFFSET(pglist_data, nr_zones);
+#ifdef CONFIG_FLAT_NODE_MEM_MAP
+ VMCOREINFO_OFFSET(pglist_data, node_mem_map);
+#endif
+ VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
+ VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
+ VMCOREINFO_OFFSET(pglist_data, node_id);
+ VMCOREINFO_OFFSET(zone, free_area);
+ VMCOREINFO_OFFSET(zone, vm_stat);
+ VMCOREINFO_OFFSET(zone, spanned_pages);
+ VMCOREINFO_OFFSET(free_area, free_list);
+ VMCOREINFO_OFFSET(list_head, next);
+ VMCOREINFO_OFFSET(list_head, prev);
+ VMCOREINFO_OFFSET(vm_struct, addr);
+ VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
+ VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
+ VMCOREINFO_NUMBER(NR_FREE_PAGES);
+ VMCOREINFO_NUMBER(PG_lru);
+ VMCOREINFO_NUMBER(PG_private);
+ VMCOREINFO_NUMBER(PG_swapcache);
+
+ arch_crash_save_vmcoreinfo();
+
+ return 0;
+}
+
+module_init(kexec_module_init)
+
projects / ms2-kexec / commitdiff