From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- kernel/kexec.c | 306 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 306 insertions(+) create mode 100644 kernel/kexec.c (limited to 'kernel/kexec.c') diff --git a/kernel/kexec.c b/kernel/kexec.c new file mode 100644 index 000000000..f0f0c6555 --- /dev/null +++ b/kernel/kexec.c @@ -0,0 +1,306 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kexec.c - kexec_load system call + * Copyright (C) 2002-2004 Eric Biederman + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kexec_internal.h" + +static int copy_user_segment_list(struct kimage *image, + unsigned long nr_segments, + struct kexec_segment __user *segments) +{ + int ret; + size_t segment_bytes; + + /* Read in the segments */ + image->nr_segments = nr_segments; + segment_bytes = nr_segments * sizeof(*segments); + ret = copy_from_user(image->segment, segments, segment_bytes); + if (ret) + ret = -EFAULT; + + return ret; +} + +static int kimage_alloc_init(struct kimage **rimage, unsigned long entry, + unsigned long nr_segments, + struct kexec_segment __user *segments, + unsigned long flags) +{ + int ret; + struct kimage *image; + bool kexec_on_panic = flags & KEXEC_ON_CRASH; + + if (kexec_on_panic) { + /* Verify we have a valid entry point */ + if ((entry < phys_to_boot_phys(crashk_res.start)) || + (entry > phys_to_boot_phys(crashk_res.end))) + return -EADDRNOTAVAIL; + } + + /* Allocate and initialize a controlling structure */ + image = do_kimage_alloc_init(); + if (!image) + return -ENOMEM; + + image->start = entry; + + ret = copy_user_segment_list(image, nr_segments, segments); + if (ret) + goto out_free_image; + + if (kexec_on_panic) { + /* Enable special crash kernel control page alloc policy. */ + image->control_page = crashk_res.start; + image->type = KEXEC_TYPE_CRASH; + } + + ret = sanity_check_segment_list(image); + if (ret) + goto out_free_image; + + /* + * Find a location for the control code buffer, and add it + * the vector of segments so that it's pages will also be + * counted as destination pages. + */ + ret = -ENOMEM; + image->control_code_page = kimage_alloc_control_pages(image, + get_order(KEXEC_CONTROL_PAGE_SIZE)); + if (!image->control_code_page) { + pr_err("Could not allocate control_code_buffer\n"); + goto out_free_image; + } + + if (!kexec_on_panic) { + image->swap_page = kimage_alloc_control_pages(image, 0); + if (!image->swap_page) { + pr_err("Could not allocate swap buffer\n"); + goto out_free_control_pages; + } + } + + *rimage = image; + return 0; +out_free_control_pages: + kimage_free_page_list(&image->control_pages); +out_free_image: + kfree(image); + return ret; +} + +static int do_kexec_load(unsigned long entry, unsigned long nr_segments, + struct kexec_segment __user *segments, unsigned long flags) +{ + struct kimage **dest_image, *image; + unsigned long i; + int ret; + + /* + * Because we write directly to the reserved memory region when loading + * crash kernels we need a serialization here to prevent multiple crash + * kernels from attempting to load simultaneously. + */ + if (!kexec_trylock()) + return -EBUSY; + + if (flags & KEXEC_ON_CRASH) { + dest_image = &kexec_crash_image; + if (kexec_crash_image) + arch_kexec_unprotect_crashkres(); + } else { + dest_image = &kexec_image; + } + + if (nr_segments == 0) { + /* Uninstall image */ + kimage_free(xchg(dest_image, NULL)); + ret = 0; + goto out_unlock; + } + if (flags & KEXEC_ON_CRASH) { + /* + * Loading another kernel to switch to if this one + * crashes. Free any current crash dump kernel before + * we corrupt it. + */ + kimage_free(xchg(&kexec_crash_image, NULL)); + } + + ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags); + if (ret) + goto out_unlock; + + if (flags & KEXEC_PRESERVE_CONTEXT) + image->preserve_context = 1; + + ret = machine_kexec_prepare(image); + if (ret) + goto out; + + /* + * Some architecture(like S390) may touch the crash memory before + * machine_kexec_prepare(), we must copy vmcoreinfo data after it. + */ + ret = kimage_crash_copy_vmcoreinfo(image); + if (ret) + goto out; + + for (i = 0; i < nr_segments; i++) { + ret = kimage_load_segment(image, &image->segment[i]); + if (ret) + goto out; + } + + kimage_terminate(image); + + ret = machine_kexec_post_load(image); + if (ret) + goto out; + + /* Install the new kernel and uninstall the old */ + image = xchg(dest_image, image); + +out: + if ((flags & KEXEC_ON_CRASH) && kexec_crash_image) + arch_kexec_protect_crashkres(); + + kimage_free(image); +out_unlock: + kexec_unlock(); + return ret; +} + +/* + * Exec Kernel system call: for obvious reasons only root may call it. + * + * This call breaks up into three pieces. + * - A generic part which loads the new kernel from the current + * address space, and very carefully places the data in the + * allocated pages. + * + * - A generic part that interacts with the kernel and tells all of + * the devices to shut down. Preventing on-going dmas, and placing + * the devices in a consistent state so a later kernel can + * reinitialize them. + * + * - A machine specific part that includes the syscall number + * and then copies the image to it's final destination. And + * jumps into the image at entry. + * + * kexec does not sync, or unmount filesystems so if you need + * that to happen you need to do that yourself. + */ + +static inline int kexec_load_check(unsigned long nr_segments, + unsigned long flags) +{ + int result; + + /* We only trust the superuser with rebooting the system. */ + if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + return -EPERM; + + /* Permit LSMs and IMA to fail the kexec */ + result = security_kernel_load_data(LOADING_KEXEC_IMAGE, false); + if (result < 0) + return result; + + /* + * kexec can be used to circumvent module loading restrictions, so + * prevent loading in that case + */ + result = security_locked_down(LOCKDOWN_KEXEC); + if (result) + return result; + + /* + * Verify we have a legal set of flags + * This leaves us room for future extensions. + */ + if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK)) + return -EINVAL; + + /* Put an artificial cap on the number + * of segments passed to kexec_load. + */ + if (nr_segments > KEXEC_SEGMENT_MAX) + return -EINVAL; + + return 0; +} + +SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, + struct kexec_segment __user *, segments, unsigned long, flags) +{ + int result; + + result = kexec_load_check(nr_segments, flags); + if (result) + return result; + + /* Verify we are on the appropriate architecture */ + if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) && + ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT)) + return -EINVAL; + + result = do_kexec_load(entry, nr_segments, segments, flags); + + return result; +} + +#ifdef CONFIG_COMPAT +COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry, + compat_ulong_t, nr_segments, + struct compat_kexec_segment __user *, segments, + compat_ulong_t, flags) +{ + struct compat_kexec_segment in; + struct kexec_segment out, __user *ksegments; + unsigned long i, result; + + result = kexec_load_check(nr_segments, flags); + if (result) + return result; + + /* Don't allow clients that don't understand the native + * architecture to do anything. + */ + if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT) + return -EINVAL; + + ksegments = compat_alloc_user_space(nr_segments * sizeof(out)); + for (i = 0; i < nr_segments; i++) { + result = copy_from_user(&in, &segments[i], sizeof(in)); + if (result) + return -EFAULT; + + out.buf = compat_ptr(in.buf); + out.bufsz = in.bufsz; + out.mem = in.mem; + out.memsz = in.memsz; + + result = copy_to_user(&ksegments[i], &out, sizeof(out)); + if (result) + return -EFAULT; + } + + result = do_kexec_load(entry, nr_segments, ksegments, flags); + + return result; +} +#endif -- cgit v1.2.3