mirror of
https://github.com/torvalds/linux.git
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e5eb28f6d1
heap optimizations". - Kuan-Wei Chiu has also sped up the library sorting code in the series "lib/sort: Optimize the number of swaps and comparisons". - Alexey Gladkov has added the ability for code running within an IPC namespace to alter its IPC and MQ limits. The series is "Allow to change ipc/mq sysctls inside ipc namespace". - Geert Uytterhoeven has contributed some dhrystone maintenance work in the series "lib: dhry: miscellaneous cleanups". - Ryusuke Konishi continues nilfs2 maintenance work in the series "nilfs2: eliminate kmap and kmap_atomic calls" "nilfs2: fix kernel bug at submit_bh_wbc()" - Nathan Chancellor has updated our build tools requirements in the series "Bump the minimum supported version of LLVM to 13.0.1". - Muhammad Usama Anjum continues with the selftests maintenance work in the series "selftests/mm: Improve run_vmtests.sh". - Oleg Nesterov has done some maintenance work against the signal code in the series "get_signal: minor cleanups and fix". Plus the usual shower of singleton patches in various parts of the tree. Please see the individual changelogs for details. -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZfMnvgAKCRDdBJ7gKXxA jjKMAP4/Upq07D4wjkMVPb+QrkipbbLpdcgJ++q3z6rba4zhPQD+M3SFriIJk/Xh tKVmvihFxfAhdDthseXcIf1nBjMALwY= =8rVc -----END PGP SIGNATURE----- Merge tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min heap optimizations". - Kuan-Wei Chiu has also sped up the library sorting code in the series "lib/sort: Optimize the number of swaps and comparisons". - Alexey Gladkov has added the ability for code running within an IPC namespace to alter its IPC and MQ limits. The series is "Allow to change ipc/mq sysctls inside ipc namespace". - Geert Uytterhoeven has contributed some dhrystone maintenance work in the series "lib: dhry: miscellaneous cleanups". - Ryusuke Konishi continues nilfs2 maintenance work in the series "nilfs2: eliminate kmap and kmap_atomic calls" "nilfs2: fix kernel bug at submit_bh_wbc()" - Nathan Chancellor has updated our build tools requirements in the series "Bump the minimum supported version of LLVM to 13.0.1". - Muhammad Usama Anjum continues with the selftests maintenance work in the series "selftests/mm: Improve run_vmtests.sh". - Oleg Nesterov has done some maintenance work against the signal code in the series "get_signal: minor cleanups and fix". Plus the usual shower of singleton patches in various parts of the tree. Please see the individual changelogs for details. * tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits) nilfs2: prevent kernel bug at submit_bh_wbc() nilfs2: fix failure to detect DAT corruption in btree and direct mappings ocfs2: enable ocfs2_listxattr for special files ocfs2: remove SLAB_MEM_SPREAD flag usage assoc_array: fix the return value in assoc_array_insert_mid_shortcut() buildid: use kmap_local_page() watchdog/core: remove sysctl handlers from public header nilfs2: use div64_ul() instead of do_div() mul_u64_u64_div_u64: increase precision by conditionally swapping a and b kexec: copy only happens before uchunk goes to zero get_signal: don't initialize ksig->info if SIGNAL_GROUP_EXIT/group_exec_task get_signal: hide_si_addr_tag_bits: fix the usage of uninitialized ksig get_signal: don't abuse ksig->info.si_signo and ksig->sig const_structs.checkpatch: add device_type Normalise "name (ad@dr)" MODULE_AUTHORs to "name <ad@dr>" dyndbg: replace kstrdup() + strchr() with kstrdup_and_replace() list: leverage list_is_head() for list_entry_is_head() nilfs2: MAINTAINERS: drop unreachable project mirror site smp: make __smp_processor_id() 0-argument macro fat: fix uninitialized field in nostale filehandles ...
1076 lines
27 KiB
C
1076 lines
27 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* kexec.c - kexec system call core code.
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* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/btf.h>
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#include <linux/capability.h>
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#include <linux/mm.h>
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#include <linux/file.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/kexec.h>
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#include <linux/mutex.h>
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#include <linux/list.h>
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#include <linux/highmem.h>
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#include <linux/syscalls.h>
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#include <linux/reboot.h>
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#include <linux/ioport.h>
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#include <linux/hardirq.h>
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#include <linux/elf.h>
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#include <linux/elfcore.h>
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#include <linux/utsname.h>
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#include <linux/numa.h>
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#include <linux/suspend.h>
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#include <linux/device.h>
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#include <linux/freezer.h>
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#include <linux/panic_notifier.h>
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#include <linux/pm.h>
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#include <linux/cpu.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/console.h>
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#include <linux/vmalloc.h>
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#include <linux/swap.h>
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#include <linux/syscore_ops.h>
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#include <linux/compiler.h>
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#include <linux/hugetlb.h>
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#include <linux/objtool.h>
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#include <linux/kmsg_dump.h>
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#include <asm/page.h>
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#include <asm/sections.h>
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#include <crypto/hash.h>
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#include "kexec_internal.h"
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atomic_t __kexec_lock = ATOMIC_INIT(0);
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/* Flag to indicate we are going to kexec a new kernel */
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bool kexec_in_progress = false;
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bool kexec_file_dbg_print;
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/*
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* When kexec transitions to the new kernel there is a one-to-one
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* mapping between physical and virtual addresses. On processors
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* where you can disable the MMU this is trivial, and easy. For
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* others it is still a simple predictable page table to setup.
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*
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* In that environment kexec copies the new kernel to its final
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* resting place. This means I can only support memory whose
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* physical address can fit in an unsigned long. In particular
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* addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
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* If the assembly stub has more restrictive requirements
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* KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
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* defined more restrictively in <asm/kexec.h>.
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*
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* The code for the transition from the current kernel to the
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* new kernel is placed in the control_code_buffer, whose size
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* is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
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* page of memory is necessary, but some architectures require more.
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* Because this memory must be identity mapped in the transition from
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* virtual to physical addresses it must live in the range
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* 0 - TASK_SIZE, as only the user space mappings are arbitrarily
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* modifiable.
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*
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* The assembly stub in the control code buffer is passed a linked list
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* of descriptor pages detailing the source pages of the new kernel,
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* and the destination addresses of those source pages. As this data
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* structure is not used in the context of the current OS, it must
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* be self-contained.
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*
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* The code has been made to work with highmem pages and will use a
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* destination page in its final resting place (if it happens
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* to allocate it). The end product of this is that most of the
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* physical address space, and most of RAM can be used.
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*
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* Future directions include:
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* - allocating a page table with the control code buffer identity
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* mapped, to simplify machine_kexec and make kexec_on_panic more
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* reliable.
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*/
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/*
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* KIMAGE_NO_DEST is an impossible destination address..., for
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* allocating pages whose destination address we do not care about.
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*/
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#define KIMAGE_NO_DEST (-1UL)
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#define PAGE_COUNT(x) (((x) + PAGE_SIZE - 1) >> PAGE_SHIFT)
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static struct page *kimage_alloc_page(struct kimage *image,
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gfp_t gfp_mask,
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unsigned long dest);
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int sanity_check_segment_list(struct kimage *image)
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{
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int i;
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unsigned long nr_segments = image->nr_segments;
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unsigned long total_pages = 0;
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unsigned long nr_pages = totalram_pages();
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/*
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* Verify we have good destination addresses. The caller is
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* responsible for making certain we don't attempt to load
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* the new image into invalid or reserved areas of RAM. This
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* just verifies it is an address we can use.
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*
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* Since the kernel does everything in page size chunks ensure
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* the destination addresses are page aligned. Too many
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* special cases crop of when we don't do this. The most
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* insidious is getting overlapping destination addresses
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* simply because addresses are changed to page size
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* granularity.
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*/
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for (i = 0; i < nr_segments; i++) {
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unsigned long mstart, mend;
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mstart = image->segment[i].mem;
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mend = mstart + image->segment[i].memsz;
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if (mstart > mend)
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return -EADDRNOTAVAIL;
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if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
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return -EADDRNOTAVAIL;
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if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
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return -EADDRNOTAVAIL;
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}
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/* Verify our destination addresses do not overlap.
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* If we alloed overlapping destination addresses
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* through very weird things can happen with no
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* easy explanation as one segment stops on another.
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*/
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for (i = 0; i < nr_segments; i++) {
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unsigned long mstart, mend;
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unsigned long j;
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mstart = image->segment[i].mem;
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mend = mstart + image->segment[i].memsz;
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for (j = 0; j < i; j++) {
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unsigned long pstart, pend;
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pstart = image->segment[j].mem;
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pend = pstart + image->segment[j].memsz;
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/* Do the segments overlap ? */
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if ((mend > pstart) && (mstart < pend))
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return -EINVAL;
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}
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}
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/* Ensure our buffer sizes are strictly less than
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* our memory sizes. This should always be the case,
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* and it is easier to check up front than to be surprised
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* later on.
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*/
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for (i = 0; i < nr_segments; i++) {
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if (image->segment[i].bufsz > image->segment[i].memsz)
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return -EINVAL;
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}
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/*
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* Verify that no more than half of memory will be consumed. If the
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* request from userspace is too large, a large amount of time will be
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* wasted allocating pages, which can cause a soft lockup.
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*/
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for (i = 0; i < nr_segments; i++) {
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if (PAGE_COUNT(image->segment[i].memsz) > nr_pages / 2)
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return -EINVAL;
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total_pages += PAGE_COUNT(image->segment[i].memsz);
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}
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if (total_pages > nr_pages / 2)
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return -EINVAL;
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#ifdef CONFIG_CRASH_DUMP
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/*
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* Verify we have good destination addresses. Normally
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* the caller is responsible for making certain we don't
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* attempt to load the new image into invalid or reserved
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* areas of RAM. But crash kernels are preloaded into a
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* reserved area of ram. We must ensure the addresses
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* are in the reserved area otherwise preloading the
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* kernel could corrupt things.
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*/
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if (image->type == KEXEC_TYPE_CRASH) {
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for (i = 0; i < nr_segments; i++) {
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unsigned long mstart, mend;
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mstart = image->segment[i].mem;
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mend = mstart + image->segment[i].memsz - 1;
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/* Ensure we are within the crash kernel limits */
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if ((mstart < phys_to_boot_phys(crashk_res.start)) ||
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(mend > phys_to_boot_phys(crashk_res.end)))
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return -EADDRNOTAVAIL;
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}
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}
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#endif
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return 0;
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}
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struct kimage *do_kimage_alloc_init(void)
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{
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struct kimage *image;
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/* Allocate a controlling structure */
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image = kzalloc(sizeof(*image), GFP_KERNEL);
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if (!image)
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return NULL;
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image->head = 0;
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image->entry = &image->head;
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image->last_entry = &image->head;
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image->control_page = ~0; /* By default this does not apply */
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image->type = KEXEC_TYPE_DEFAULT;
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/* Initialize the list of control pages */
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INIT_LIST_HEAD(&image->control_pages);
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/* Initialize the list of destination pages */
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INIT_LIST_HEAD(&image->dest_pages);
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/* Initialize the list of unusable pages */
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INIT_LIST_HEAD(&image->unusable_pages);
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#ifdef CONFIG_CRASH_HOTPLUG
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image->hp_action = KEXEC_CRASH_HP_NONE;
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image->elfcorehdr_index = -1;
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image->elfcorehdr_updated = false;
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#endif
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return image;
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}
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int kimage_is_destination_range(struct kimage *image,
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unsigned long start,
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unsigned long end)
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{
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unsigned long i;
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for (i = 0; i < image->nr_segments; i++) {
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unsigned long mstart, mend;
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mstart = image->segment[i].mem;
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mend = mstart + image->segment[i].memsz - 1;
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if ((end >= mstart) && (start <= mend))
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return 1;
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}
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return 0;
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}
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static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
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{
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struct page *pages;
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if (fatal_signal_pending(current))
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return NULL;
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pages = alloc_pages(gfp_mask & ~__GFP_ZERO, order);
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if (pages) {
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unsigned int count, i;
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pages->mapping = NULL;
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set_page_private(pages, order);
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count = 1 << order;
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for (i = 0; i < count; i++)
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SetPageReserved(pages + i);
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arch_kexec_post_alloc_pages(page_address(pages), count,
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gfp_mask);
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if (gfp_mask & __GFP_ZERO)
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for (i = 0; i < count; i++)
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clear_highpage(pages + i);
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}
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return pages;
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}
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static void kimage_free_pages(struct page *page)
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{
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unsigned int order, count, i;
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order = page_private(page);
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count = 1 << order;
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arch_kexec_pre_free_pages(page_address(page), count);
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for (i = 0; i < count; i++)
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ClearPageReserved(page + i);
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__free_pages(page, order);
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}
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void kimage_free_page_list(struct list_head *list)
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{
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struct page *page, *next;
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list_for_each_entry_safe(page, next, list, lru) {
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list_del(&page->lru);
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kimage_free_pages(page);
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}
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}
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static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
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unsigned int order)
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{
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/* Control pages are special, they are the intermediaries
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* that are needed while we copy the rest of the pages
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* to their final resting place. As such they must
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* not conflict with either the destination addresses
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* or memory the kernel is already using.
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*
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* The only case where we really need more than one of
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* these are for architectures where we cannot disable
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* the MMU and must instead generate an identity mapped
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* page table for all of the memory.
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*
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* At worst this runs in O(N) of the image size.
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*/
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struct list_head extra_pages;
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struct page *pages;
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unsigned int count;
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count = 1 << order;
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INIT_LIST_HEAD(&extra_pages);
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/* Loop while I can allocate a page and the page allocated
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* is a destination page.
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*/
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do {
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unsigned long pfn, epfn, addr, eaddr;
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pages = kimage_alloc_pages(KEXEC_CONTROL_MEMORY_GFP, order);
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if (!pages)
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break;
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pfn = page_to_boot_pfn(pages);
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epfn = pfn + count;
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addr = pfn << PAGE_SHIFT;
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eaddr = (epfn << PAGE_SHIFT) - 1;
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if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
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kimage_is_destination_range(image, addr, eaddr)) {
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list_add(&pages->lru, &extra_pages);
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pages = NULL;
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}
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} while (!pages);
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if (pages) {
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/* Remember the allocated page... */
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list_add(&pages->lru, &image->control_pages);
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|
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/* Because the page is already in it's destination
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* location we will never allocate another page at
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* that address. Therefore kimage_alloc_pages
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* will not return it (again) and we don't need
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* to give it an entry in image->segment[].
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*/
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}
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/* Deal with the destination pages I have inadvertently allocated.
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*
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* Ideally I would convert multi-page allocations into single
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* page allocations, and add everything to image->dest_pages.
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*
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* For now it is simpler to just free the pages.
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*/
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kimage_free_page_list(&extra_pages);
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return pages;
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}
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#ifdef CONFIG_CRASH_DUMP
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static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
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unsigned int order)
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{
|
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/* Control pages are special, they are the intermediaries
|
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* 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
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* or memory the kernel is already using.
|
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*
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* Control pages are also the only pags we must allocate
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* when loading a crash kernel. All of the other pages
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* are specified by the segments and we just memcpy
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* into them directly.
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|
*
|
|
* 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.
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|
*
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|
* Given the low demand this implements a very simple
|
|
* allocator that finds the first hole of the appropriate
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* size in the reserved memory region, and allocates all
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* of the memory up to and including the hole.
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|
*/
|
|
unsigned long hole_start, hole_end, size;
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struct page *pages;
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pages = NULL;
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size = (1 << order) << PAGE_SHIFT;
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hole_start = ALIGN(image->control_page, size);
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hole_end = hole_start + size - 1;
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while (hole_end <= crashk_res.end) {
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unsigned long i;
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cond_resched();
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|
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if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT)
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break;
|
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/* See if I overlap any of the segments */
|
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for (i = 0; i < image->nr_segments; i++) {
|
|
unsigned long mstart, mend;
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|
|
|
mstart = image->segment[i].mem;
|
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mend = mstart + image->segment[i].memsz - 1;
|
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if ((hole_end >= mstart) && (hole_start <= mend)) {
|
|
/* Advance the hole to the end of the segment */
|
|
hole_start = ALIGN(mend, size);
|
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hole_end = hole_start + size - 1;
|
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break;
|
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}
|
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}
|
|
/* 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);
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|
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;
|
|
}
|