| /* |
| * kexec.c - kexec system call |
| * 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. |
| */ |
| |
| #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/spinlock.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 <asm/page.h> |
| #include <asm/uaccess.h> |
| #include <asm/io.h> |
| #include <asm/system.h> |
| #include <asm/sections.h> |
| |
| /* 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) || panic_on_oops) |
| 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_CODE_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_CODE_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_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_CODE_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 int kimage_terminate(struct kimage *image) |
| { |
| if (*image->entry != 0) |
| image->entry++; |
| |
| *image->entry = IND_DONE; |
| |
| return 0; |
| } |
| |
| #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. |
| */ |
| 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; |
| /* |
| * A home grown binary mutex. |
| * Nothing can wait so this mutex is safe to use |
| * in interrupt context :) |
| */ |
| static int kexec_lock; |
| |
| asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, |
| struct kexec_segment __user *segments, |
| unsigned long flags) |
| { |
| struct kimage **dest_image, *image; |
| int locked; |
| 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. |
| */ |
| locked = xchg(&kexec_lock, 1); |
| if (locked) |
| 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; |
| |
| 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; |
| } |
| result = kimage_terminate(image); |
| if (result) |
| goto out; |
| } |
| /* Install the new kernel, and Uninstall the old */ |
| image = xchg(dest_image, image); |
| |
| out: |
| locked = xchg(&kexec_lock, 0); /* Release the mutex */ |
| BUG_ON(!locked); |
| 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) |
| { |
| int locked; |
| |
| |
| /* Take the kexec_lock 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... |
| */ |
| locked = xchg(&kexec_lock, 1); |
| if (!locked) { |
| 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); |
| } |
| locked = xchg(&kexec_lock, 0); |
| BUG_ON(!locked); |
| } |
| } |
| |
| 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_CPUS)) |
| 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); |
| } |
| |
| static int __init crash_notes_memory_init(void) |
| { |
| /* 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; |
| } |
| return 0; |
| } |
| module_init(crash_notes_memory_init) |
| |
| |
| /* |
| * 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); |
| } |
| |
| static int __init crash_save_vmcoreinfo_init(void) |
| { |
| VMCOREINFO_OSRELEASE(init_uts_ns.name.release); |
| VMCOREINFO_PAGESIZE(PAGE_SIZE); |
| |
| VMCOREINFO_SYMBOL(init_uts_ns); |
| VMCOREINFO_SYMBOL(node_online_map); |
| VMCOREINFO_SYMBOL(swapper_pg_dir); |
| VMCOREINFO_SYMBOL(_stext); |
| |
| #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_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(crash_save_vmcoreinfo_init) |