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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * kexec.c - kexec system call core code.
- * Copyright (C) 2002-2004 Eric Biederman <[email protected]>
- */
- #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- #include <linux/capability.h>
- #include <linux/mm.h>
- #include <linux/file.h>
- #include <linux/slab.h>
- #include <linux/fs.h>
- #include <linux/kexec.h>
- #include <linux/mutex.h>
- #include <linux/list.h>
- #include <linux/highmem.h>
- #include <linux/syscalls.h>
- #include <linux/reboot.h>
- #include <linux/ioport.h>
- #include <linux/hardirq.h>
- #include <linux/elf.h>
- #include <linux/elfcore.h>
- #include <linux/utsname.h>
- #include <linux/numa.h>
- #include <linux/suspend.h>
- #include <linux/device.h>
- #include <linux/freezer.h>
- #include <linux/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);
- /* Per cpu memory for storing cpu states in case of system crash. */
- note_buf_t __percpu *crash_notes;
- /* Flag to indicate we are going to kexec a new kernel */
- bool kexec_in_progress = false;
- /* Location of the reserved area for the crash kernel */
- struct resource crashk_res = {
- .name = "Crash kernel",
- .start = 0,
- .end = 0,
- .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
- .desc = IORES_DESC_CRASH_KERNEL
- };
- struct resource crashk_low_res = {
- .name = "Crash kernel",
- .start = 0,
- .end = 0,
- .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
- .desc = IORES_DESC_CRASH_KERNEL
- };
- int kexec_should_crash(struct task_struct *p)
- {
- /*
- * If crash_kexec_post_notifiers is enabled, don't run
- * crash_kexec() here yet, which must be run after panic
- * notifiers in panic().
- */
- if (crash_kexec_post_notifiers)
- return 0;
- /*
- * There are 4 panic() calls in make_task_dead() path, each of which
- * corresponds to each of these 4 conditions.
- */
- if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
- return 1;
- return 0;
- }
- int kexec_crash_loaded(void)
- {
- return !!kexec_crash_image;
- }
- EXPORT_SYMBOL_GPL(kexec_crash_loaded);
- /*
- * When kexec transitions to the new kernel there is a one-to-one
- * mapping between physical and virtual addresses. On processors
- * where you can disable the MMU this is trivial, and easy. For
- * others it is still a simple predictable page table to setup.
- *
- * In that environment kexec copies the new kernel to its final
- * resting place. This means I can only support memory whose
- * physical address can fit in an unsigned long. In particular
- * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
- * If the assembly stub has more restrictive requirements
- * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
- * defined more restrictively in <asm/kexec.h>.
- *
- * The code for the transition from the current kernel to the
- * 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;
- /*
- * 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;
- }
- }
- 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);
- 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;
- 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;
- 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;
- }
- 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;
- 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 = (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);
- image->control_page = hole_end;
- 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;
- }
- 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;
- }
- int kimage_crash_copy_vmcoreinfo(struct kimage *image)
- {
- struct page *vmcoreinfo_page;
- void *safecopy;
- if (image->type != KEXEC_TYPE_CRASH)
- return 0;
- /*
- * For kdump, allocate one vmcoreinfo safe copy from the
- * crash memory. as we have arch_kexec_protect_crashkres()
- * after kexec syscall, we naturally protect it from write
- * (even read) access under kernel direct mapping. But on
- * the other hand, we still need to operate it when crash
- * happens to generate vmcoreinfo note, hereby we rely on
- * vmap for this purpose.
- */
- vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
- if (!vmcoreinfo_page) {
- pr_warn("Could not allocate vmcoreinfo buffer\n");
- return -ENOMEM;
- }
- safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
- if (!safecopy) {
- pr_warn("Could not vmap vmcoreinfo buffer\n");
- return -ENOMEM;
- }
- image->vmcoreinfo_data_copy = safecopy;
- crash_update_vmcoreinfo_safecopy(safecopy);
- return 0;
- }
- 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)
- {
- int result;
- destination &= PAGE_MASK;
- result = kimage_add_entry(image, destination | IND_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);
- 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 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;
- if (image->vmcoreinfo_data_copy) {
- crash_update_vmcoreinfo_safecopy(NULL);
- vunmap(image->vmcoreinfo_data_copy);
- }
- 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))
- 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);
- /* 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);
- kunmap_local(ptr);
- if (result) {
- result = -EFAULT;
- goto out;
- }
- ubytes -= uchunk;
- maddr += mchunk;
- if (image->file_mode)
- kbuf += mchunk;
- else
- buf += mchunk;
- mbytes -= mchunk;
- cond_resched();
- }
- 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;
- 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);
- }
- /* 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);
- kexec_flush_icache_page(page);
- kunmap_local(ptr);
- arch_kexec_pre_free_pages(page_address(page), 1);
- if (result) {
- result = -EFAULT;
- goto out;
- }
- ubytes -= uchunk;
- maddr += mchunk;
- if (image->file_mode)
- kbuf += mchunk;
- else
- buf += mchunk;
- mbytes -= mchunk;
- cond_resched();
- }
- out:
- return result;
- }
- 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;
- }
- struct kimage *kexec_image;
- struct kimage *kexec_crash_image;
- int kexec_load_disabled;
- #ifdef CONFIG_SYSCTL
- 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,
- },
- { }
- };
- static int __init kexec_core_sysctl_init(void)
- {
- register_sysctl_init("kernel", kexec_core_sysctls);
- return 0;
- }
- late_initcall(kexec_core_sysctl_init);
- #endif
- /*
- * No panic_cpu check version of crash_kexec(). This function is called
- * only when panic_cpu holds the current CPU number; this is the only CPU
- * which processes crash_kexec routines.
- */
- void __noclone __crash_kexec(struct pt_regs *regs)
- {
- /* 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...
- */
- if (kexec_trylock()) {
- 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);
- }
- kexec_unlock();
- }
- }
- STACK_FRAME_NON_STANDARD(__crash_kexec);
- void crash_kexec(struct pt_regs *regs)
- {
- int old_cpu, this_cpu;
- /*
- * Only one CPU is allowed to execute the crash_kexec() code as with
- * panic(). Otherwise parallel calls of panic() and crash_kexec()
- * may stop each other. To exclude them, we use panic_cpu here too.
- */
- this_cpu = raw_smp_processor_id();
- old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
- if (old_cpu == PANIC_CPU_INVALID) {
- /* This is the 1st CPU which comes here, so go ahead. */
- __crash_kexec(regs);
- /*
- * Reset panic_cpu to allow another panic()/crash_kexec()
- * call.
- */
- atomic_set(&panic_cpu, PANIC_CPU_INVALID);
- }
- }
- ssize_t crash_get_memory_size(void)
- {
- ssize_t size = 0;
- if (!kexec_trylock())
- return -EBUSY;
- if (crashk_res.end != crashk_res.start)
- size = resource_size(&crashk_res);
- kexec_unlock();
- return size;
- }
- int crash_shrink_memory(unsigned long new_size)
- {
- int ret = 0;
- unsigned long start, end;
- unsigned long old_size;
- struct resource *ram_res;
- if (!kexec_trylock())
- return -EBUSY;
- if (kexec_crash_image) {
- ret = -ENOENT;
- goto unlock;
- }
- start = crashk_res.start;
- end = crashk_res.end;
- old_size = (end == 0) ? 0 : end - start + 1;
- new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
- if (new_size >= old_size) {
- ret = (new_size == old_size) ? 0 : -EINVAL;
- goto unlock;
- }
- ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
- if (!ram_res) {
- ret = -ENOMEM;
- goto unlock;
- }
- end = start + new_size;
- crash_free_reserved_phys_range(end, crashk_res.end);
- if ((start == end) && (crashk_res.parent != NULL))
- release_resource(&crashk_res);
- ram_res->start = end;
- ram_res->end = crashk_res.end;
- ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
- ram_res->name = "System RAM";
- crashk_res.end = end - 1;
- insert_resource(&iomem_resource, ram_res);
- unlock:
- kexec_unlock();
- return ret;
- }
- 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.common.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. */
- size_t size, align;
- /*
- * crash_notes could be allocated across 2 vmalloc pages when percpu
- * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
- * pages are also on 2 continuous physical pages. In this case the
- * 2nd part of crash_notes in 2nd page could be lost since only the
- * starting address and size of crash_notes are exported through sysfs.
- * Here round up the size of crash_notes to the nearest power of two
- * and pass it to __alloc_percpu as align value. This can make sure
- * crash_notes is allocated inside one physical page.
- */
- size = sizeof(note_buf_t);
- align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
- /*
- * Break compile if size is bigger than PAGE_SIZE since crash_notes
- * definitely will be in 2 pages with that.
- */
- BUILD_BUG_ON(size > PAGE_SIZE);
- crash_notes = __alloc_percpu(size, align);
- if (!crash_notes) {
- pr_warn("Memory allocation for saving cpu register states failed\n");
- return -ENOMEM;
- }
- return 0;
- }
- subsys_initcall(crash_notes_memory_init);
- /*
- * 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();
- /*
- * 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;
- }
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