xref: /linux/scripts/livepatch/klp-build (revision dea622e183d34e6a4f90acfee9abb605885432bf)
1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3#
4# Build a livepatch module
5
6# shellcheck disable=SC1090,SC2155
7
8if (( BASH_VERSINFO[0]  < 4 || \
9     (BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] < 4) )); then
10		echo "error: this script requires bash 4.4+" >&2
11	exit 1
12fi
13
14set -o errexit
15set -o errtrace
16set -o pipefail
17set -o nounset
18
19# Allow doing 'cmd | mapfile -t array' instead of 'mapfile -t array < <(cmd)'.
20# This helps keep execution in pipes so pipefail+errexit can catch errors.
21shopt -s lastpipe
22
23unset DEBUG_CLONE DIFF_CHECKSUM SKIP_CLEANUP XTRACE
24
25REPLACE=1
26SHORT_CIRCUIT=0
27JOBS="$(getconf _NPROCESSORS_ONLN)"
28VERBOSE="-s"
29shopt -o xtrace | grep -q 'on' && XTRACE=1
30
31# Avoid removing the previous $TMP_DIR until args have been fully processed.
32KEEP_TMP=1
33
34SCRIPT="$(basename "$0")"
35SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
36FIX_PATCH_LINES="$SCRIPT_DIR/fix-patch-lines"
37
38SRC="$(pwd)"
39OBJ="$(pwd)"
40
41CONFIG="$OBJ/.config"
42TMP_DIR="$OBJ/klp-tmp"
43
44ORIG_DIR="$TMP_DIR/orig"
45PATCHED_DIR="$TMP_DIR/patched"
46DIFF_DIR="$TMP_DIR/diff"
47KMOD_DIR="$TMP_DIR/kmod"
48
49STASH_DIR="$TMP_DIR/stash"
50TIMESTAMP="$TMP_DIR/timestamp"
51PATCH_TMP_DIR="$TMP_DIR/tmp"
52
53KLP_DIFF_LOG="$DIFF_DIR/diff.log"
54
55grep0() {
56	command grep "$@" || true
57}
58
59status() {
60	echo "$*"
61}
62
63warn() {
64	echo "error: $SCRIPT: $*" >&2
65}
66
67die() {
68	warn "$@"
69	exit 1
70}
71
72declare -a STASHED_FILES
73
74stash_file() {
75	local file="$1"
76	local rel_file="${file#"$SRC"/}"
77
78	[[ ! -e "$file" ]] && die "no file to stash: $file"
79
80	mkdir -p "$STASH_DIR/$(dirname "$rel_file")"
81	cp -f "$file" "$STASH_DIR/$rel_file"
82
83	STASHED_FILES+=("$rel_file")
84}
85
86restore_files() {
87	local file
88
89	for file in "${STASHED_FILES[@]}"; do
90		mv -f "$STASH_DIR/$file" "$SRC/$file" || warn "can't restore file: $file"
91	done
92
93	STASHED_FILES=()
94}
95
96cleanup() {
97	set +o nounset
98	revert_patches "--recount"
99	restore_files
100	[[ "$KEEP_TMP" -eq 0 ]] && rm -rf "$TMP_DIR"
101	return 0
102}
103
104trap_err() {
105	warn "line ${BASH_LINENO[0]}: '$BASH_COMMAND'"
106}
107
108trap cleanup  EXIT INT TERM HUP
109trap trap_err ERR
110
111__usage() {
112	cat <<EOF
113Usage: $SCRIPT [OPTIONS] PATCH_FILE(s)
114Generate a livepatch module.
115
116Options:
117   -f, --show-first-changed	Show address of first changed instruction
118   -j, --jobs=<jobs>		Build jobs to run simultaneously [default: $JOBS]
119   -o, --output=<file.ko>	Output file [default: livepatch-<patch-name>.ko]
120       --no-replace		Disable livepatch atomic replace
121   -v, --verbose		Pass V=1 to kernel/module builds
122
123Advanced Options:
124   -d, --debug			Show symbol/reloc cloning decisions
125   -S, --short-circuit=STEP	Start at build step (requires prior --keep-tmp)
126				   1|orig	Build original kernel (default)
127				   2|patched	Build patched kernel
128				   3|diff	Diff objects
129				   4|kmod	Build patch module
130   -T, --keep-tmp		Preserve tmp dir on exit
131
132EOF
133}
134
135usage() {
136	__usage >&2
137}
138
139process_args() {
140	local keep_tmp=0
141	local short
142	local long
143	local args
144
145	short="hfj:o:vdS:T"
146	long="help,show-first-changed,jobs:,output:,no-replace,verbose,debug,short-circuit:,keep-tmp"
147
148	args=$(getopt --options "$short" --longoptions "$long" -- "$@") || {
149		echo; usage; exit
150	}
151	eval set -- "$args"
152
153	while true; do
154		case "$1" in
155			-h | --help)
156				usage
157				exit 0
158				;;
159			-f | --show-first-changed)
160				DIFF_CHECKSUM=1
161				shift
162				;;
163			-j | --jobs)
164				JOBS="$2"
165				shift 2
166				;;
167			-o | --output)
168				[[ "$2" != *.ko ]] && die "output filename should end with .ko"
169				OUTFILE="$2"
170				NAME="$(basename "$OUTFILE")"
171				NAME="${NAME%.ko}"
172				NAME="$(module_name_string "$NAME")"
173				shift 2
174				;;
175			--no-replace)
176				REPLACE=0
177				shift
178				;;
179			-v | --verbose)
180				VERBOSE="V=1"
181				shift
182				;;
183			-d | --debug)
184				DEBUG_CLONE=1
185				keep_tmp=1
186				shift
187				;;
188			-S | --short-circuit)
189				[[ ! -d "$TMP_DIR" ]] && die "--short-circuit requires preserved klp-tmp dir"
190				keep_tmp=1
191				case "$2" in
192					1 | orig)	SHORT_CIRCUIT=1; ;;
193					2 | patched)	SHORT_CIRCUIT=2; ;;
194					3 | diff)	SHORT_CIRCUIT=3; ;;
195					4 | mod)	SHORT_CIRCUIT=4; ;;
196					*)		die "invalid short-circuit step '$2'" ;;
197				esac
198				shift 2
199				;;
200			-T | --keep-tmp)
201				keep_tmp=1
202				shift
203				;;
204			--)
205				shift
206				break
207				;;
208			*)
209				usage
210				exit 1
211				;;
212		esac
213	done
214
215	if [[ $# -eq 0 ]]; then
216		usage
217		exit 1
218	fi
219
220	KEEP_TMP="$keep_tmp"
221	PATCHES=("$@")
222}
223
224# temporarily disable xtrace for especially verbose code
225xtrace_save() {
226	[[ -v XTRACE ]] && set +x
227	return 0
228}
229
230xtrace_restore() {
231	[[ -v XTRACE ]] && set -x
232	return 0
233}
234
235validate_config() {
236	xtrace_save "reading .config"
237	source "$CONFIG" || die "no .config file in $(dirname "$CONFIG")"
238	xtrace_restore
239
240	[[ -v CONFIG_LIVEPATCH ]] ||			\
241		die "CONFIG_LIVEPATCH not enabled"
242
243	[[ -v CONFIG_KLP_BUILD ]] ||			\
244		die "CONFIG_KLP_BUILD not enabled"
245
246	[[ -v CONFIG_GCC_PLUGIN_LATENT_ENTROPY ]] &&	\
247		die "kernel option 'CONFIG_GCC_PLUGIN_LATENT_ENTROPY' not supported"
248
249	[[ -v CONFIG_GCC_PLUGIN_RANDSTRUCT ]] &&	\
250		die "kernel option 'CONFIG_GCC_PLUGIN_RANDSTRUCT' not supported"
251
252	[[ -v CONFIG_AS_IS_LLVM ]] &&				\
253		[[ "$CONFIG_AS_VERSION" -lt 200000 ]] &&	\
254		die "Clang assembler version < 20 not supported"
255
256	return 0
257}
258
259# Only allow alphanumerics and '_' and '-' in the module name.  Everything else
260# is replaced with '-'.  Also truncate to 55 chars so the full name + NUL
261# terminator fits in the kernel's 56-byte module name array.
262module_name_string() {
263	echo "${1//[^a-zA-Z0-9_-]/-}" | cut -c 1-55
264}
265
266# If the module name wasn't specified on the cmdline with --output, give it a
267# name based on the patch name.
268set_module_name() {
269	[[ -v NAME ]] && return 0
270
271	if [[ "${#PATCHES[@]}" -eq 1 ]]; then
272		NAME="$(basename "${PATCHES[0]}")"
273		NAME="${NAME%.*}"
274	else
275		NAME="patch"
276	fi
277
278	NAME="livepatch-$NAME"
279	NAME="$(module_name_string "$NAME")"
280
281	OUTFILE="$NAME.ko"
282}
283
284# Hardcode the value printed by the localversion script to prevent patch
285# application from appending it with '+' due to a dirty git working tree.
286set_kernelversion() {
287	local file="$SRC/scripts/setlocalversion"
288	local kernelrelease
289
290	stash_file "$file"
291
292	kernelrelease="$(cd "$SRC" && make syncconfig &>/dev/null && make -s kernelrelease)"
293	[[ -z "$kernelrelease" ]] && die "failed to get kernel version"
294
295	sed -i "2i echo $kernelrelease; exit 0" scripts/setlocalversion
296}
297
298get_patch_files() {
299	local patch="$1"
300
301	grep0 -E '^(--- |\+\+\+ )' "$patch"			\
302		| gawk '{print $2}'				\
303		| sed 's|^[^/]*/||'				\
304		| sort -u
305}
306
307# Make sure git re-stats the changed files
308git_refresh() {
309	local patch="$1"
310	local files=()
311
312	[[ ! -e "$SRC/.git" ]] && return
313
314	get_patch_files "$patch" | mapfile -t files
315
316	(
317		cd "$SRC"
318		git update-index -q --refresh -- "${files[@]}"
319	)
320}
321
322check_unsupported_patches() {
323	local patch
324
325	for patch in "${PATCHES[@]}"; do
326		local files=()
327
328		get_patch_files "$patch" | mapfile -t files
329
330		for file in "${files[@]}"; do
331			case "$file" in
332				lib/*|*.S)
333					die "unsupported patch to $file"
334					;;
335			esac
336		done
337	done
338}
339
340apply_patch() {
341	local patch="$1"
342	shift
343	local extra_args=("$@")
344
345	[[ ! -f "$patch" ]] && die "$patch doesn't exist"
346
347	(
348		cd "$SRC"
349
350		# The sed strips the version signature from 'git format-patch',
351		# otherwise 'git apply --recount' warns.
352		sed -n '/^-- /q;p' "$patch" |
353			git apply "${extra_args[@]}"
354	)
355
356	APPLIED_PATCHES+=("$patch")
357}
358
359revert_patch() {
360	local patch="$1"
361	shift
362	local extra_args=("$@")
363	local tmp=()
364
365	(
366		cd "$SRC"
367
368		sed -n '/^-- /q;p' "$patch" |
369			git apply --reverse "${extra_args[@]}"
370	)
371	git_refresh "$patch"
372
373	for p in "${APPLIED_PATCHES[@]}"; do
374		[[ "$p" == "$patch" ]] && continue
375		tmp+=("$p")
376	done
377
378	APPLIED_PATCHES=("${tmp[@]}")
379}
380
381apply_patches() {
382	local patch
383
384	for patch in "${PATCHES[@]}"; do
385		apply_patch "$patch"
386	done
387}
388
389revert_patches() {
390	local extra_args=("$@")
391	local patches=("${APPLIED_PATCHES[@]}")
392
393	for (( i=${#patches[@]}-1 ; i>=0 ; i-- )) ; do
394		revert_patch "${patches[$i]}" "${extra_args[@]}"
395	done
396
397	APPLIED_PATCHES=()
398}
399
400validate_patches() {
401	check_unsupported_patches
402	apply_patches
403	revert_patches
404}
405
406do_init() {
407	# We're not yet smart enough to handle anything other than in-tree
408	# builds in pwd.
409	[[ ! "$SRC" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
410	[[ ! "$OBJ" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
411
412	(( SHORT_CIRCUIT <= 1 )) && rm -rf "$TMP_DIR"
413	mkdir -p "$TMP_DIR"
414
415	APPLIED_PATCHES=()
416
417	[[ -x "$FIX_PATCH_LINES" ]] || die "can't find fix-patch-lines"
418
419	validate_config
420	set_module_name
421	set_kernelversion
422}
423
424# Refresh the patch hunk headers, specifically the line numbers and counts.
425refresh_patch() {
426	local patch="$1"
427	local tmpdir="$PATCH_TMP_DIR"
428	local files=()
429
430	rm -rf "$tmpdir"
431	mkdir -p "$tmpdir/a"
432	mkdir -p "$tmpdir/b"
433
434	# Get all source files affected by the patch
435	get_patch_files "$patch" | mapfile -t files
436
437	# Copy orig source files to 'a'
438	( cd "$SRC" && echo "${files[@]}" | xargs cp --parents --target-directory="$tmpdir/a" )
439
440	# Copy patched source files to 'b'
441	apply_patch "$patch" --recount
442	( cd "$SRC" && echo "${files[@]}" | xargs cp --parents --target-directory="$tmpdir/b" )
443	revert_patch "$patch" --recount
444
445	# Diff 'a' and 'b' to make a clean patch
446	( cd "$tmpdir" && git diff --no-index --no-prefix a b > "$patch" ) || true
447}
448
449# Copy the patches to a temporary directory, fix their lines so as not to
450# affect the __LINE__ macro for otherwise unchanged functions further down the
451# file, and update $PATCHES to point to the fixed patches.
452fix_patches() {
453	local idx
454	local i
455
456	rm -f "$TMP_DIR"/*.patch
457
458	idx=0001
459	for i in "${!PATCHES[@]}"; do
460		local old_patch="${PATCHES[$i]}"
461		local tmp_patch="$TMP_DIR/tmp.patch"
462		local patch="${PATCHES[$i]}"
463		local new_patch
464
465		new_patch="$TMP_DIR/$idx-fixed-$(basename "$patch")"
466
467		cp -f "$old_patch" "$tmp_patch"
468		refresh_patch "$tmp_patch"
469		"$FIX_PATCH_LINES" "$tmp_patch" > "$new_patch"
470		refresh_patch "$new_patch"
471
472		PATCHES[i]="$new_patch"
473
474		rm -f "$tmp_patch"
475		idx=$(printf "%04d" $(( 10#$idx + 1 )))
476	done
477}
478
479clean_kernel() {
480	local cmd=()
481
482	cmd=("make")
483	cmd+=("--silent")
484	cmd+=("-j$JOBS")
485	cmd+=("clean")
486
487	(
488		cd "$SRC"
489		"${cmd[@]}"
490	)
491}
492
493build_kernel() {
494	local log="$TMP_DIR/build.log"
495	local objtool_args=()
496	local cmd=()
497
498	objtool_args=("--checksum")
499
500	cmd=("make")
501
502	# When a patch to a kernel module references a newly created unexported
503	# symbol which lives in vmlinux or another kernel module, the patched
504	# kernel build fails with the following error:
505	#
506	#   ERROR: modpost: "klp_string" [fs/xfs/xfs.ko] undefined!
507	#
508	# The undefined symbols are working as designed in that case.  They get
509	# resolved later when the livepatch module build link pulls all the
510	# disparate objects together into the same kernel module.
511	#
512	# It would be good to have a way to tell modpost to skip checking for
513	# undefined symbols altogether.  For now, just convert the error to a
514	# warning with KBUILD_MODPOST_WARN, and grep out the warning to avoid
515	# confusing the user.
516	#
517	cmd+=("KBUILD_MODPOST_WARN=1")
518
519	cmd+=("$VERBOSE")
520	cmd+=("-j$JOBS")
521	cmd+=("KCFLAGS=-ffunction-sections -fdata-sections")
522	cmd+=("OBJTOOL_ARGS=${objtool_args[*]}")
523	cmd+=("vmlinux")
524	cmd+=("modules")
525
526	(
527		cd "$SRC"
528		"${cmd[@]}"							\
529			1> >(tee -a "$log")					\
530			2> >(tee -a "$log" | grep0 -v "modpost.*undefined!" >&2)
531	)
532}
533
534find_objects() {
535	local opts=("$@")
536
537	# Find root-level vmlinux.o and non-root-level .ko files,
538	# excluding klp-tmp/ and .git/
539	find "$OBJ" \( -path "$TMP_DIR" -o -path "$OBJ/.git" -o	-regex "$OBJ/[^/][^/]*\.ko" \) -prune -o \
540		    -type f "${opts[@]}"				\
541		    \( -name "*.ko" -o -path "$OBJ/vmlinux.o" \)	\
542		    -printf '%P\n'
543}
544
545# Copy all .o archives to $ORIG_DIR
546copy_orig_objects() {
547	local files=()
548
549	rm -rf "$ORIG_DIR"
550	mkdir -p "$ORIG_DIR"
551
552	find_objects | mapfile -t files
553
554	xtrace_save "copying orig objects"
555	for _file in "${files[@]}"; do
556		local rel_file="${_file/.ko/.o}"
557		local file="$OBJ/$rel_file"
558		local file_dir="$(dirname "$file")"
559		local orig_file="$ORIG_DIR/$rel_file"
560		local orig_dir="$(dirname "$orig_file")"
561
562		[[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file"
563
564		mkdir -p "$orig_dir"
565		cp -f "$file" "$orig_dir"
566	done
567	xtrace_restore
568
569	mv -f "$TMP_DIR/build.log" "$ORIG_DIR"
570	touch "$TIMESTAMP"
571}
572
573# Copy all changed objects to $PATCHED_DIR
574copy_patched_objects() {
575	local files=()
576	local opts=()
577	local found=0
578
579	rm -rf "$PATCHED_DIR"
580	mkdir -p "$PATCHED_DIR"
581
582	# Note this doesn't work with some configs, thus the 'cmp' below.
583	opts=("-newer")
584	opts+=("$TIMESTAMP")
585
586	find_objects "${opts[@]}" | mapfile -t files
587
588	xtrace_save "copying changed objects"
589	for _file in "${files[@]}"; do
590		local rel_file="${_file/.ko/.o}"
591		local file="$OBJ/$rel_file"
592		local orig_file="$ORIG_DIR/$rel_file"
593		local patched_file="$PATCHED_DIR/$rel_file"
594		local patched_dir="$(dirname "$patched_file")"
595
596		[[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file"
597
598		cmp -s "$orig_file" "$file" && continue
599
600		mkdir -p "$patched_dir"
601		cp -f "$file" "$patched_dir"
602		found=1
603	done
604	xtrace_restore
605
606	(( found == 0 )) && die "no changes detected"
607
608	mv -f "$TMP_DIR/build.log" "$PATCHED_DIR"
609}
610
611# Diff changed objects, writing output object to $DIFF_DIR
612diff_objects() {
613	local log="$KLP_DIFF_LOG"
614	local files=()
615	local opts=()
616
617	rm -rf "$DIFF_DIR"
618	mkdir -p "$DIFF_DIR"
619
620	find "$PATCHED_DIR" -type f -name "*.o" | mapfile -t files
621	[[ ${#files[@]} -eq 0 ]] && die "no changes detected"
622
623	[[ -v DEBUG_CLONE ]] && opts=("--debug")
624
625	# Diff all changed objects
626	for file in "${files[@]}"; do
627		local rel_file="${file#"$PATCHED_DIR"/}"
628		local orig_file="$rel_file"
629		local patched_file="$PATCHED_DIR/$rel_file"
630		local out_file="$DIFF_DIR/$rel_file"
631		local filter=()
632		local cmd=()
633
634		mkdir -p "$(dirname "$out_file")"
635
636		cmd=("$SRC/tools/objtool/objtool")
637		cmd+=("klp")
638		cmd+=("diff")
639		(( ${#opts[@]} > 0 )) && cmd+=("${opts[@]}")
640		cmd+=("$orig_file")
641		cmd+=("$patched_file")
642		cmd+=("$out_file")
643
644		if [[ -v DIFF_CHECKSUM ]]; then
645			filter=("grep0")
646			filter+=("-Ev")
647			filter+=("DEBUG: .*checksum: ")
648		else
649			filter=("cat")
650		fi
651
652		(
653			cd "$ORIG_DIR"
654			"${cmd[@]}"							\
655				1> >(tee -a "$log")					\
656				2> >(tee -a "$log" | "${filter[@]}" >&2) ||		\
657				die "objtool klp diff failed"
658		)
659	done
660}
661
662# For each changed object, run objtool with --debug-checksum to get the
663# per-instruction checksums, and then diff those to find the first changed
664# instruction for each function.
665diff_checksums() {
666	local orig_log="$ORIG_DIR/checksum.log"
667	local patched_log="$PATCHED_DIR/checksum.log"
668	local -A funcs
669	local cmd=()
670	local line
671	local file
672	local func
673
674	gawk '/\.o: changed function: / {
675		sub(/:$/, "", $1)
676		print $1, $NF
677	}' "$KLP_DIFF_LOG" | mapfile -t lines
678
679	for line in "${lines[@]}"; do
680		read -r file func <<< "$line"
681		if [[ ! -v funcs["$file"] ]]; then
682			funcs["$file"]="$func"
683		else
684			funcs["$file"]+=" $func"
685		fi
686	done
687
688	cmd=("$SRC/tools/objtool/objtool")
689	cmd+=("--checksum")
690	cmd+=("--link")
691	cmd+=("--dry-run")
692
693	for file in "${!funcs[@]}"; do
694		local opt="--debug-checksum=${funcs[$file]// /,}"
695
696		(
697			cd "$ORIG_DIR"
698			"${cmd[@]}" "$opt" "$file" &> "$orig_log" || \
699				( cat "$orig_log" >&2; die "objtool --debug-checksum failed" )
700
701			cd "$PATCHED_DIR"
702			"${cmd[@]}" "$opt" "$file" &> "$patched_log" ||	\
703				( cat "$patched_log" >&2; die "objtool --debug-checksum failed" )
704		)
705
706		for func in ${funcs[$file]}; do
707			diff <( grep0 -E "^DEBUG: .*checksum: $func " "$orig_log"    | sed "s|$ORIG_DIR/||")	\
708			     <( grep0 -E "^DEBUG: .*checksum: $func " "$patched_log" | sed "s|$PATCHED_DIR/||")	\
709				| gawk '/^< DEBUG: / {
710					gsub(/:/, "")
711					printf "%s: %s: %s\n", $3, $5, $6
712					exit
713			}' || true
714		done
715	done
716}
717
718# Build and post-process livepatch module in $KMOD_DIR
719build_patch_module() {
720	local makefile="$KMOD_DIR/Kbuild"
721	local log="$KMOD_DIR/build.log"
722	local kmod_file
723	local cflags=()
724	local files=()
725	local cmd=()
726
727	rm -rf "$KMOD_DIR"
728	mkdir -p "$KMOD_DIR"
729
730	cp -f "$SRC/scripts/livepatch/init.c" "$KMOD_DIR"
731
732	echo "obj-m := $NAME.o" > "$makefile"
733	echo -n "$NAME-y := init.o" >> "$makefile"
734
735	find "$DIFF_DIR" -type f -name "*.o" | mapfile -t files
736	[[ ${#files[@]} -eq 0 ]] && die "no changes detected"
737
738	for file in "${files[@]}"; do
739		local rel_file="${file#"$DIFF_DIR"/}"
740		local orig_file="$ORIG_DIR/$rel_file"
741		local orig_dir="$(dirname "$orig_file")"
742		local kmod_file="$KMOD_DIR/$rel_file"
743		local kmod_dir="$(dirname "$kmod_file")"
744		local cmd_file="$kmod_dir/.$(basename "$file").cmd"
745
746		mkdir -p "$kmod_dir"
747		cp -f "$file" "$kmod_dir"
748
749		# Tell kbuild this is a prebuilt object
750		cp -f "$file" "${kmod_file}_shipped"
751
752		# Make modpost happy
753		touch "$cmd_file"
754
755		echo -n " $rel_file" >> "$makefile"
756	done
757
758	echo >> "$makefile"
759
760	cflags=("-ffunction-sections")
761	cflags+=("-fdata-sections")
762	[[ $REPLACE -eq 0 ]] && cflags+=("-DKLP_NO_REPLACE")
763
764	cmd=("make")
765	cmd+=("$VERBOSE")
766	cmd+=("-j$JOBS")
767	cmd+=("--directory=.")
768	cmd+=("M=$KMOD_DIR")
769	cmd+=("KCFLAGS=${cflags[*]}")
770
771	# Build a "normal" kernel module with init.c and the diffed objects
772	(
773		cd "$SRC"
774		"${cmd[@]}"							\
775			1> >(tee -a "$log")					\
776			2> >(tee -a "$log" >&2)
777	)
778
779	kmod_file="$KMOD_DIR/$NAME.ko"
780
781	# Save off the intermediate binary for debugging
782	cp -f "$kmod_file" "$kmod_file.orig"
783
784	# Work around issue where slight .config change makes corrupt BTF
785	objcopy --remove-section=.BTF "$kmod_file"
786
787	# Fix (and work around) linker wreckage for klp syms / relocs
788	"$SRC/tools/objtool/objtool" klp post-link "$kmod_file" || die "objtool klp post-link failed"
789
790	cp -f "$kmod_file" "$OUTFILE"
791}
792
793
794################################################################################
795
796process_args "$@"
797do_init
798
799if (( SHORT_CIRCUIT <= 1 )); then
800	status "Validating patch(es)"
801	validate_patches
802	status "Building original kernel"
803	clean_kernel
804	build_kernel
805	status "Copying original object files"
806	copy_orig_objects
807fi
808
809if (( SHORT_CIRCUIT <= 2 )); then
810	status "Fixing patch(es)"
811	fix_patches
812	apply_patches
813	status "Building patched kernel"
814	build_kernel
815	revert_patches
816	status "Copying patched object files"
817	copy_patched_objects
818fi
819
820if (( SHORT_CIRCUIT <= 3 )); then
821	status "Diffing objects"
822	diff_objects
823	if [[ -v DIFF_CHECKSUM ]]; then
824		status "Finding first changed instructions"
825		diff_checksums
826	fi
827fi
828
829if (( SHORT_CIRCUIT <= 4 )); then
830	status "Building patch module: $OUTFILE"
831	build_patch_module
832fi
833
834status "SUCCESS"
835