Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * kexec.c - kexec_load system call
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/capability.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/file.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/kexec.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/mutex.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/list.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/syscalls.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/vmalloc.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include "kexec_internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) static int copy_user_segment_list(struct kimage *image,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 				  unsigned long nr_segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 				  struct kexec_segment __user *segments)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	size_t segment_bytes;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	/* Read in the segments */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	image->nr_segments = nr_segments;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 	segment_bytes = nr_segments * sizeof(*segments);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	ret = copy_from_user(image->segment, segments, segment_bytes);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 		ret = -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 			     unsigned long nr_segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 			     struct kexec_segment __user *segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 			     unsigned long flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	struct kimage *image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	bool kexec_on_panic = flags & KEXEC_ON_CRASH;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	if (kexec_on_panic) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 		/* Verify we have a valid entry point */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 		if ((entry < phys_to_boot_phys(crashk_res.start)) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 		    (entry > phys_to_boot_phys(crashk_res.end)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 			return -EADDRNOTAVAIL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	/* Allocate and initialize a controlling structure */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	image = do_kimage_alloc_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	if (!image)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	image->start = entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	ret = copy_user_segment_list(image, nr_segments, segments);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 		goto out_free_image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	if (kexec_on_panic) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		/* Enable special crash kernel control page alloc policy. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		image->control_page = crashk_res.start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		image->type = KEXEC_TYPE_CRASH;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	ret = sanity_check_segment_list(image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		goto out_free_image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	 * Find a location for the control code buffer, and add it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	 * the vector of segments so that it's pages will also be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	 * counted as destination pages.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	ret = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	image->control_code_page = kimage_alloc_control_pages(image,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 					   get_order(KEXEC_CONTROL_PAGE_SIZE));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	if (!image->control_code_page) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		pr_err("Could not allocate control_code_buffer\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 		goto out_free_image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	if (!kexec_on_panic) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		image->swap_page = kimage_alloc_control_pages(image, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 		if (!image->swap_page) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 			pr_err("Could not allocate swap buffer\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 			goto out_free_control_pages;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	*rimage = image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) out_free_control_pages:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	kimage_free_page_list(&image->control_pages);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) out_free_image:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	kfree(image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 		struct kexec_segment __user *segments, unsigned long flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	struct kimage **dest_image, *image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	unsigned long i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	if (flags & KEXEC_ON_CRASH) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		dest_image = &kexec_crash_image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 		if (kexec_crash_image)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 			arch_kexec_unprotect_crashkres();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 		dest_image = &kexec_image;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	if (nr_segments == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 		/* Uninstall image */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 		kimage_free(xchg(dest_image, NULL));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	if (flags & KEXEC_ON_CRASH) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 		 * Loading another kernel to switch to if this one
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		 * crashes.  Free any current crash dump kernel before
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 		 * we corrupt it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		kimage_free(xchg(&kexec_crash_image, NULL));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	if (flags & KEXEC_PRESERVE_CONTEXT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		image->preserve_context = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	ret = machine_kexec_prepare(image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	 * Some architecture(like S390) may touch the crash memory before
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	ret = kimage_crash_copy_vmcoreinfo(image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	for (i = 0; i < nr_segments; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		ret = kimage_load_segment(image, &image->segment[i]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 			goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	kimage_terminate(image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	ret = machine_kexec_post_load(image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	/* Install the new kernel and uninstall the old */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	image = xchg(dest_image, image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 		arch_kexec_protect_crashkres();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	kimage_free(image);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178)  * Exec Kernel system call: for obvious reasons only root may call it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180)  * This call breaks up into three pieces.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181)  * - A generic part which loads the new kernel from the current
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182)  *   address space, and very carefully places the data in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183)  *   allocated pages.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185)  * - A generic part that interacts with the kernel and tells all of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)  *   the devices to shut down.  Preventing on-going dmas, and placing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187)  *   the devices in a consistent state so a later kernel can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188)  *   reinitialize them.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)  * - A machine specific part that includes the syscall number
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191)  *   and then copies the image to it's final destination.  And
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192)  *   jumps into the image at entry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194)  * kexec does not sync, or unmount filesystems so if you need
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195)  * that to happen you need to do that yourself.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) static inline int kexec_load_check(unsigned long nr_segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 				   unsigned long flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	int result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	/* We only trust the superuser with rebooting the system. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	/* Permit LSMs and IMA to fail the kexec */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	result = security_kernel_load_data(LOADING_KEXEC_IMAGE, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	if (result < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 		return result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	 * kexec can be used to circumvent module loading restrictions, so
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	 * prevent loading in that case
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	result = security_locked_down(LOCKDOWN_KEXEC);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	if (result)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 		return result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	 * Verify we have a legal set of flags
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	 * This leaves us room for future extensions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	/* Put an artificial cap on the number
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 	 * of segments passed to kexec_load.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	if (nr_segments > KEXEC_SEGMENT_MAX)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 		struct kexec_segment __user *, segments, unsigned long, flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 	int result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	result = kexec_load_check(nr_segments, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 	if (result)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 		return result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	/* Verify we are on the appropriate architecture */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 		((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	/* Because we write directly to the reserved memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	 * region when loading crash kernels we need a mutex here to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	 * prevent multiple crash  kernels from attempting to load
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	 * simultaneously, and to prevent a crash kernel from loading
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	 * over the top of a in use crash kernel.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	 * KISS: always take the mutex.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	if (!mutex_trylock(&kexec_mutex))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 		return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	result = do_kexec_load(entry, nr_segments, segments, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	mutex_unlock(&kexec_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	return result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) #ifdef CONFIG_COMPAT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 		       compat_ulong_t, nr_segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 		       struct compat_kexec_segment __user *, segments,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		       compat_ulong_t, flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 	struct compat_kexec_segment in;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	struct kexec_segment out, __user *ksegments;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	unsigned long i, result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	result = kexec_load_check(nr_segments, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	if (result)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		return result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	/* Don't allow clients that don't understand the native
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	 * architecture to do anything.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 	for (i = 0; i < nr_segments; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 		result = copy_from_user(&in, &segments[i], sizeof(in));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		if (result)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 		out.buf   = compat_ptr(in.buf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 		out.bufsz = in.bufsz;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 		out.mem   = in.mem;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 		out.memsz = in.memsz;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 		result = copy_to_user(&ksegments[i], &out, sizeof(out));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 		if (result)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 	/* Because we write directly to the reserved memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	 * region when loading crash kernels we need a mutex here to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 	 * prevent multiple crash  kernels from attempting to load
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	 * simultaneously, and to prevent a crash kernel from loading
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	 * over the top of a in use crash kernel.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 	 * KISS: always take the mutex.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	if (!mutex_trylock(&kexec_mutex))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 		return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	result = do_kexec_load(entry, nr_segments, ksegments, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	mutex_unlock(&kexec_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	return result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) #endif