| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * kexec.c - kexec system call core code. |
| * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com> |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/btf.h> |
| #include <linux/capability.h> |
| #include <linux/mm.h> |
| #include <linux/file.h> |
| #include <linux/slab.h> |
| #include <linux/fs.h> |
| #include <linux/kexec.h> |
| #include <linux/mutex.h> |
| #include <linux/list.h> |
| #include <linux/highmem.h> |
| #include <linux/syscalls.h> |
| #include <linux/reboot.h> |
| #include <linux/ioport.h> |
| #include <linux/hardirq.h> |
| #include <linux/elf.h> |
| #include <linux/elfcore.h> |
| #include <linux/utsname.h> |
| #include <linux/numa.h> |
| #include <linux/suspend.h> |
| #include <linux/device.h> |
| #include <linux/freezer.h> |
| #include <linux/panic_notifier.h> |
| #include <linux/pm.h> |
| #include <linux/cpu.h> |
| #include <linux/uaccess.h> |
| #include <linux/io.h> |
| #include <linux/console.h> |
| #include <linux/vmalloc.h> |
| #include <linux/swap.h> |
| #include <linux/syscore_ops.h> |
| #include <linux/compiler.h> |
| #include <linux/hugetlb.h> |
| #include <linux/objtool.h> |
| #include <linux/kmsg_dump.h> |
| |
| #include <asm/page.h> |
| #include <asm/sections.h> |
| |
| #include <crypto/hash.h> |
| #include "kexec_internal.h" |
| |
| atomic_t __kexec_lock = ATOMIC_INIT(0); |
| |
| /* Flag to indicate we are going to kexec a new kernel */ |
| bool kexec_in_progress = false; |
| |
| bool kexec_file_dbg_print; |
| |
| /* |
| * 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 |
| * new kernel is placed in the control_code_buffer, whose size |
| * is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single |
| * page of memory is necessary, but some architectures require more. |
| * Because this memory must be identity mapped in the transition from |
| * virtual to physical addresses it must live in the range |
| * 0 - TASK_SIZE, as only the user space mappings are arbitrarily |
| * modifiable. |
| * |
| * The assembly stub in the control code buffer is passed a linked list |
| * of descriptor pages detailing the source pages of the new kernel, |
| * and the destination addresses of those source pages. As this data |
| * structure is not used in the context of the current OS, it must |
| * be self-contained. |
| * |
| * The code has been made to work with highmem pages and will use a |
| * destination page in its final resting place (if it happens |
| * to allocate it). The end product of this is that most of the |
| * physical address space, and most of RAM can be used. |
| * |
| * Future directions include: |
| * - allocating a page table with the control code buffer identity |
| * mapped, to simplify machine_kexec and make kexec_on_panic more |
| * reliable. |
| */ |
| |
| /* |
| * KIMAGE_NO_DEST is an impossible destination address..., for |
| * allocating pages whose destination address we do not care about. |
| */ |
| #define KIMAGE_NO_DEST (-1UL) |
| #define PAGE_COUNT(x) (((x) + PAGE_SIZE - 1) >> PAGE_SHIFT) |
| |
| static struct page *kimage_alloc_page(struct kimage *image, |
| gfp_t gfp_mask, |
| unsigned long dest); |
| |
| int sanity_check_segment_list(struct kimage *image) |
| { |
| int i; |
| unsigned long nr_segments = image->nr_segments; |
| unsigned long total_pages = 0; |
| unsigned long nr_pages = totalram_pages(); |
| |
| /* |
| * 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 addresses 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. |
| */ |
| for (i = 0; i < nr_segments; i++) { |
| unsigned long mstart, mend; |
| |
| mstart = image->segment[i].mem; |
| mend = mstart + image->segment[i].memsz; |
| if (mstart > mend) |
| return -EADDRNOTAVAIL; |
| if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK)) |
| return -EADDRNOTAVAIL; |
| if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT) |
| return -EADDRNOTAVAIL; |
| } |
| |
| /* 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. |
| */ |
| 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)) |
| return -EINVAL; |
| } |
| } |
| |
| /* 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. |
| */ |
| for (i = 0; i < nr_segments; i++) { |
| if (image->segment[i].bufsz > image->segment[i].memsz) |
| return -EINVAL; |
| } |
| |
| /* |
| * Verify that no more than half of memory will be consumed. If the |
| * request from userspace is too large, a large amount of time will be |
| * wasted allocating pages, which can cause a soft lockup. |
| */ |
| for (i = 0; i < nr_segments; i++) { |
| if (PAGE_COUNT(image->segment[i].memsz) > nr_pages / 2) |
| return -EINVAL; |
| |
| total_pages += PAGE_COUNT(image->segment[i].memsz); |
| } |
| |
| if (total_pages > nr_pages / 2) |
| return -EINVAL; |
| |
| #ifdef CONFIG_CRASH_DUMP |
| /* |
| * 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. |
| */ |
| |
| if (image->type == KEXEC_TYPE_CRASH) { |
| 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 < phys_to_boot_phys(crashk_res.start)) || |
| (mend > phys_to_boot_phys(crashk_res.end))) |
| return -EADDRNOTAVAIL; |
| } |
| } |
| #endif |
| |
| return 0; |
| } |
| |
| struct kimage *do_kimage_alloc_init(void) |
| { |
| struct kimage *image; |
| |
| /* Allocate a controlling structure */ |
| image = kzalloc(sizeof(*image), GFP_KERNEL); |
| if (!image) |
| return NULL; |
| |
| image->head = 0; |
| image->entry = &image->head; |
| image->last_entry = &image->head; |
| image->control_page = ~0; /* By default this does not apply */ |
| 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 unusable pages */ |
| INIT_LIST_HEAD(&image->unusable_pages); |
| |
| #ifdef CONFIG_CRASH_HOTPLUG |
| image->hp_action = KEXEC_CRASH_HP_NONE; |
| image->elfcorehdr_index = -1; |
| image->elfcorehdr_updated = false; |
| #endif |
| |
| return image; |
| } |
| |
| 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 - 1; |
| 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; |
| |
| if (fatal_signal_pending(current)) |
| return NULL; |
| pages = alloc_pages(gfp_mask & ~__GFP_ZERO, 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); |
| |
| arch_kexec_post_alloc_pages(page_address(pages), count, |
| gfp_mask); |
| |
| if (gfp_mask & __GFP_ZERO) |
| for (i = 0; i < count; i++) |
| clear_highpage(pages + i); |
| } |
| |
| return pages; |
| } |
| |
| static void kimage_free_pages(struct page *page) |
| { |
| unsigned int order, count, i; |
| |
| order = page_private(page); |
| count = 1 << order; |
| |
| arch_kexec_pre_free_pages(page_address(page), count); |
| |
| for (i = 0; i < count; i++) |
| ClearPageReserved(page + i); |
| __free_pages(page, order); |
| } |
| |
| void kimage_free_page_list(struct list_head *list) |
| { |
| struct page *page, *next; |
| |
| list_for_each_entry_safe(page, next, list, 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(KEXEC_CONTROL_MEMORY_GFP, order); |
| if (!pages) |
| break; |
| pfn = page_to_boot_pfn(pages); |
| epfn = pfn + count; |
| addr = pfn << PAGE_SHIFT; |
| eaddr = (epfn << PAGE_SHIFT) - 1; |
| 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 everything to image->dest_pages. |
| * |
| * For now it is simpler to just free the pages. |
| */ |
| kimage_free_page_list(&extra_pages); |
| |
| return pages; |
| } |
| |
| #ifdef CONFIG_CRASH_DUMP |
| 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 = ALIGN(image->control_page, size); |
| hole_end = hole_start + size - 1; |
| while (hole_end <= crashk_res.end) { |
| unsigned long i; |
| |
| cond_resched(); |
| |
| if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT) |
| 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 = ALIGN(mend, size); |
| 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); |
| image->control_page = hole_end + 1; |
| break; |
| } |
| } |
| |
| /* Ensure that these pages are decrypted if SME is enabled. */ |
| if (pages) |
| arch_kexec_post_alloc_pages(page_address(pages), 1 << order, 0); |
| |
| return pages; |
| } |
| #endif |
| |
| |
| 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; |
| #ifdef CONFIG_CRASH_DUMP |
| case KEXEC_TYPE_CRASH: |
| pages = kimage_alloc_crash_control_pages(image, order); |
| break; |
| #endif |
| } |
| |
| 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_boot_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) |
| { |
| destination &= PAGE_MASK; |
| |
| return kimage_add_entry(image, destination | IND_DESTINATION); |
| } |
| |
| |
| static int kimage_add_page(struct kimage *image, unsigned long page) |
| { |
| page &= PAGE_MASK; |
| |
| return kimage_add_entry(image, page | IND_SOURCE); |
| } |
| |
| |
| 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 unusable pages I have cached */ |
| kimage_free_page_list(&image->unusable_pages); |
| |
| } |
| |
| 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) ? \ |
| boot_phys_to_virt((entry & PAGE_MASK)) : ptr + 1) |
| |
| static void kimage_free_entry(kimage_entry_t entry) |
| { |
| struct page *page; |
| |
| page = boot_pfn_to_page(entry >> PAGE_SHIFT); |
| kimage_free_pages(page); |
| } |
| |
| void kimage_free(struct kimage *image) |
| { |
| kimage_entry_t *ptr, entry; |
| kimage_entry_t ind = 0; |
| |
| if (!image) |
| return; |
| |
| #ifdef CONFIG_CRASH_DUMP |
| if (image->vmcoreinfo_data_copy) { |
| crash_update_vmcoreinfo_safecopy(NULL); |
| vunmap(image->vmcoreinfo_data_copy); |
| } |
| #endif |
| |
| 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); |
| |
| /* |
| * Free up any temporary buffers allocated. This might hit if |
| * error occurred much later after buffer allocation. |
| */ |
| if (image->file_mode) |
| kimage_file_post_load_cleanup(image); |
| |
| 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_boot_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_boot_pfn(page) > |
| (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) { |
| list_add(&page->lru, &image->unusable_pages); |
| continue; |
| } |
| addr = page_to_boot_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 - 1)) |
| 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 = boot_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; |
| } |
| page = old_page; |
| break; |
| } |
| /* Place the page on the destination list, to be used 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; |
| size_t ubytes, mbytes; |
| int result; |
| unsigned char __user *buf = NULL; |
| unsigned char *kbuf = NULL; |
| |
| if (image->file_mode) |
| kbuf = segment->kbuf; |
| else |
| 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_boot_pfn(page) |
| << PAGE_SHIFT); |
| if (result < 0) |
| goto out; |
| |
| ptr = kmap_local_page(page); |
| /* Start with a clear page */ |
| clear_page(ptr); |
| ptr += maddr & ~PAGE_MASK; |
| mchunk = min_t(size_t, mbytes, |
| PAGE_SIZE - (maddr & ~PAGE_MASK)); |
| uchunk = min(ubytes, mchunk); |
| |
| if (uchunk) { |
| /* For file based kexec, source pages are in kernel memory */ |
| if (image->file_mode) |
| memcpy(ptr, kbuf, uchunk); |
| else |
| result = copy_from_user(ptr, buf, uchunk); |
| ubytes -= uchunk; |
| if (image->file_mode) |
| kbuf += uchunk; |
| else |
| buf += uchunk; |
| } |
| kunmap_local(ptr); |
| if (result) { |
| result = -EFAULT; |
| goto out; |
| } |
| maddr += mchunk; |
| mbytes -= mchunk; |
| |
| cond_resched(); |
| } |
| out: |
| return result; |
| } |
| |
| #ifdef CONFIG_CRASH_DUMP |
| 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; |
| size_t ubytes, mbytes; |
| int result; |
| unsigned char __user *buf = NULL; |
| unsigned char *kbuf = NULL; |
| |
| result = 0; |
| if (image->file_mode) |
| kbuf = segment->kbuf; |
| else |
| buf = segment->buf; |
| ubytes = segment->bufsz; |
| mbytes = segment->memsz; |
| maddr = segment->mem; |
| while (mbytes) { |
| struct page *page; |
| char *ptr; |
| size_t uchunk, mchunk; |
| |
| page = boot_pfn_to_page(maddr >> PAGE_SHIFT); |
| if (!page) { |
| result = -ENOMEM; |
| goto out; |
| } |
| arch_kexec_post_alloc_pages(page_address(page), 1, 0); |
| ptr = kmap_local_page(page); |
| ptr += maddr & ~PAGE_MASK; |
| mchunk = min_t(size_t, mbytes, |
| PAGE_SIZE - (maddr & ~PAGE_MASK)); |
| uchunk = min(ubytes, mchunk); |
| if (mchunk > uchunk) { |
| /* Zero the trailing part of the page */ |
| memset(ptr + uchunk, 0, mchunk - uchunk); |
| } |
| |
| if (uchunk) { |
| /* For file based kexec, source pages are in kernel memory */ |
| if (image->file_mode) |
| memcpy(ptr, kbuf, uchunk); |
| else |
| result = copy_from_user(ptr, buf, uchunk); |
| ubytes -= uchunk; |
| if (image->file_mode) |
| kbuf += uchunk; |
| else |
| buf += uchunk; |
| } |
| kexec_flush_icache_page(page); |
| kunmap_local(ptr); |
| arch_kexec_pre_free_pages(page_address(page), 1); |
| if (result) { |
| result = -EFAULT; |
| goto out; |
| } |
| maddr += mchunk; |
| mbytes -= mchunk; |
| |
| cond_resched(); |
| } |
| out: |
| return result; |
| } |
| #endif |
| |
| 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; |
| #ifdef CONFIG_CRASH_DUMP |
| case KEXEC_TYPE_CRASH: |
| result = kimage_load_crash_segment(image, segment); |
| break; |
| #endif |
| } |
| |
| return result; |
| } |
| |
| struct kexec_load_limit { |
| /* Mutex protects the limit count. */ |
| struct mutex mutex; |
| int limit; |
| }; |
| |
| static struct kexec_load_limit load_limit_reboot = { |
| .mutex = __MUTEX_INITIALIZER(load_limit_reboot.mutex), |
| .limit = -1, |
| }; |
| |
| static struct kexec_load_limit load_limit_panic = { |
| .mutex = __MUTEX_INITIALIZER(load_limit_panic.mutex), |
| .limit = -1, |
| }; |
| |
| struct kimage *kexec_image; |
| struct kimage *kexec_crash_image; |
| static int kexec_load_disabled; |
| |
| #ifdef CONFIG_SYSCTL |
| static int kexec_limit_handler(struct ctl_table *table, int write, |
| void *buffer, size_t *lenp, loff_t *ppos) |
| { |
| struct kexec_load_limit *limit = table->data; |
| int val; |
| struct ctl_table tmp = { |
| .data = &val, |
| .maxlen = sizeof(val), |
| .mode = table->mode, |
| }; |
| int ret; |
| |
| if (write) { |
| ret = proc_dointvec(&tmp, write, buffer, lenp, ppos); |
| if (ret) |
| return ret; |
| |
| if (val < 0) |
| return -EINVAL; |
| |
| mutex_lock(&limit->mutex); |
| if (limit->limit != -1 && val >= limit->limit) |
| ret = -EINVAL; |
| else |
| limit->limit = val; |
| mutex_unlock(&limit->mutex); |
| |
| return ret; |
| } |
| |
| mutex_lock(&limit->mutex); |
| val = limit->limit; |
| mutex_unlock(&limit->mutex); |
| |
| return proc_dointvec(&tmp, write, buffer, lenp, ppos); |
| } |
| |
| static struct ctl_table kexec_core_sysctls[] = { |
| { |
| .procname = "kexec_load_disabled", |
| .data = &kexec_load_disabled, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| /* only handle a transition from default "0" to "1" */ |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = SYSCTL_ONE, |
| .extra2 = SYSCTL_ONE, |
| }, |
| { |
| .procname = "kexec_load_limit_panic", |
| .data = &load_limit_panic, |
| .mode = 0644, |
| .proc_handler = kexec_limit_handler, |
| }, |
| { |
| .procname = "kexec_load_limit_reboot", |
| .data = &load_limit_reboot, |
| .mode = 0644, |
| .proc_handler = kexec_limit_handler, |
| }, |
| }; |
| |
| static int __init kexec_core_sysctl_init(void) |
| { |
| register_sysctl_init("kernel", kexec_core_sysctls); |
| return 0; |
| } |
| late_initcall(kexec_core_sysctl_init); |
| #endif |
| |
| bool kexec_load_permitted(int kexec_image_type) |
| { |
| struct kexec_load_limit *limit; |
| |
| /* |
| * Only the superuser can use the kexec syscall and if it has not |
| * been disabled. |
| */ |
| if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) |
| return false; |
| |
| /* Check limit counter and decrease it.*/ |
| limit = (kexec_image_type == KEXEC_TYPE_CRASH) ? |
| &load_limit_panic : &load_limit_reboot; |
| mutex_lock(&limit->mutex); |
| if (!limit->limit) { |
| mutex_unlock(&limit->mutex); |
| return false; |
| } |
| if (limit->limit != -1) |
| limit->limit--; |
| mutex_unlock(&limit->mutex); |
| |
| return true; |
| } |
| |
| /* |
| * 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 (!kexec_trylock()) |
| return -EBUSY; |
| if (!kexec_image) { |
| error = -EINVAL; |
| goto Unlock; |
| } |
| |
| #ifdef CONFIG_KEXEC_JUMP |
| if (kexec_image->preserve_context) { |
| pm_prepare_console(); |
| error = freeze_processes(); |
| if (error) { |
| error = -EBUSY; |
| goto Restore_console; |
| } |
| suspend_console(); |
| error = dpm_suspend_start(PMSG_FREEZE); |
| if (error) |
| goto Resume_console; |
| /* At this point, dpm_suspend_start() has been called, |
| * but *not* dpm_suspend_end(). We *must* call |
| * dpm_suspend_end() 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 = dpm_suspend_end(PMSG_FREEZE); |
| if (error) |
| goto Resume_devices; |
| error = suspend_disable_secondary_cpus(); |
| if (error) |
| goto Enable_cpus; |
| local_irq_disable(); |
| error = syscore_suspend(); |
| if (error) |
| goto Enable_irqs; |
| } else |
| #endif |
| { |
| kexec_in_progress = true; |
| kernel_restart_prepare("kexec reboot"); |
| migrate_to_reboot_cpu(); |
| syscore_shutdown(); |
| |
| /* |
| * migrate_to_reboot_cpu() disables CPU hotplug assuming that |
| * no further code needs to use CPU hotplug (which is true in |
| * the reboot case). However, the kexec path depends on using |
| * CPU hotplug again; so re-enable it here. |
| */ |
| cpu_hotplug_enable(); |
| pr_notice("Starting new kernel\n"); |
| machine_shutdown(); |
| } |
| |
| kmsg_dump(KMSG_DUMP_SHUTDOWN); |
| machine_kexec(kexec_image); |
| |
| #ifdef CONFIG_KEXEC_JUMP |
| if (kexec_image->preserve_context) { |
| syscore_resume(); |
| Enable_irqs: |
| local_irq_enable(); |
| Enable_cpus: |
| suspend_enable_secondary_cpus(); |
| dpm_resume_start(PMSG_RESTORE); |
| Resume_devices: |
| dpm_resume_end(PMSG_RESTORE); |
| Resume_console: |
| resume_console(); |
| thaw_processes(); |
| Restore_console: |
| pm_restore_console(); |
| } |
| #endif |
| |
| Unlock: |
| kexec_unlock(); |
| return error; |
| } |