13 files changed, 1097 insertions, 23 deletions
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 6af392f9cd02..68e6fafcb80c 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -28,8 +28,10 @@ endif
 KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
 
 ifdef CONFIG_CC_IS_CLANG
-# The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable.
+# The kernel builds with '-std=gnu11' and '-fms-extensions' so use of GNU and
+# Microsoft extensions is acceptable.
 KBUILD_CFLAGS += -Wno-gnu
+KBUILD_CFLAGS += -Wno-microsoft-anon-tag
 
 # Clang checks for overflow/truncation with '%p', while GCC does not:
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 1d581ba5df66..28a1c08e3b22 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -20,7 +20,7 @@ name-fix-token = $(subst $(comma),_,$(subst -,_,$1))
 name-fix = $(call stringify,$(call name-fix-token,$1))
 basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget))
 modname_flags  = -DKBUILD_MODNAME=$(call name-fix,$(modname)) \
-		 -D__KBUILD_MODNAME=kmod_$(call name-fix-token,$(modname))
+		 -D__KBUILD_MODNAME=$(call name-fix-token,$(modname))
 modfile_flags  = -DKBUILD_MODFILE=$(call stringify,$(modfile))
 
 _c_flags       = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
@@ -191,13 +191,13 @@ objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE)		+= --static-call
 objtool-args-$(CONFIG_HAVE_UACCESS_VALIDATION)		+= --uaccess
 objtool-args-$(or $(CONFIG_GCOV_KERNEL),$(CONFIG_KCOV))	+= --no-unreachable
 objtool-args-$(CONFIG_PREFIX_SYMBOLS)			+= --prefix=$(CONFIG_FUNCTION_PADDING_BYTES)
-objtool-args-$(CONFIG_OBJTOOL_WERROR)			+= --Werror
+objtool-args-$(CONFIG_OBJTOOL_WERROR)			+= --werror
 
 objtool-args = $(objtool-args-y)					\
 	$(if $(delay-objtool), --link)					\
 	$(if $(part-of-module), --module)
 
-delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))
+delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT),$(CONFIG_KLP_BUILD))
 
 cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool-args) $@)
 cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 23c8751285d7..527352c222ff 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -41,7 +41,7 @@ objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
 ifeq ($(delay-objtool),y)
 vmlinux-objtool-args-y					+= $(objtool-args-y)
 else
-vmlinux-objtool-args-$(CONFIG_OBJTOOL_WERROR)		+= --Werror
+vmlinux-objtool-args-$(CONFIG_OBJTOOL_WERROR)		+= --werror
 endif
 
 vmlinux-objtool-args-$(CONFIG_NOINSTR_VALIDATION)	+= --noinstr \
@@ -63,11 +63,15 @@ quiet_cmd_ld_vmlinux.o = LD      $@
 	--start-group $(KBUILD_VMLINUX_LIBS) --end-group \
 	$(cmd_objtool)
 
+cmd_check_function_names = $(srctree)/scripts/check-function-names.sh $@
+
 define rule_ld_vmlinux.o
 	$(call cmd_and_savecmd,ld_vmlinux.o)
 	$(call cmd,gen_objtooldep)
+	$(call cmd,check_function_names)
 endef
 
+
 vmlinux.o: $(initcalls-lds) vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed_rule,ld_vmlinux.o)
 
diff --git a/scripts/atomic/gen-atomic-instrumented.sh b/scripts/atomic/gen-atomic-instrumented.sh
index 592f3ec89b5f..9c1d53f81eb2 100755
--- a/scripts/atomic/gen-atomic-instrumented.sh
+++ b/scripts/atomic/gen-atomic-instrumented.sh
@@ -12,7 +12,7 @@ gen_param_check()
 	local arg="$1"; shift
 	local type="${arg%%:*}"
 	local name="$(gen_param_name "${arg}")"
-	local rw="write"
+	local rw="atomic_write"
 
 	case "${type#c}" in
 	i) return;;
@@ -20,14 +20,17 @@ gen_param_check()
 
 	if [ ${type#c} != ${type} ]; then
 		# We don't write to constant parameters.
-		rw="read"
+		rw="atomic_read"
+	elif [ "${type}" = "p" ] ; then
+		# The "old" argument in try_cmpxchg() gets accessed non-atomically
+		rw="read_write"
 	elif [ "${meta}" != "s" ]; then
 		# An atomic RMW: if this parameter is not a constant, and this atomic is
 		# not just a 's'tore, this parameter is both read from and written to.
-		rw="read_write"
+		rw="atomic_read_write"
 	fi
 
-	printf "\tinstrument_atomic_${rw}(${name}, sizeof(*${name}));\n"
+	printf "\tinstrument_${rw}(${name}, sizeof(*${name}));\n"
 }
 
 #gen_params_checks(meta, arg...)
diff --git a/scripts/check-function-names.sh b/scripts/check-function-names.sh
new file mode 100755
index 000000000000..410042591cfc
--- /dev/null
+++ b/scripts/check-function-names.sh
@@ -0,0 +1,25 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Certain function names are disallowed due to section name ambiguities
+# introduced by -ffunction-sections.
+#
+# See the comment above TEXT_MAIN in include/asm-generic/vmlinux.lds.h.
+
+objfile="$1"
+
+if [ ! -f "$objfile" ]; then
+	echo "usage: $0 <file.o>" >&2
+	exit 1
+fi
+
+bad_symbols=$(nm "$objfile" | awk '$2 ~ /^[TtWw]$/ {print $3}' | grep -E '^(startup|exit|split|unlikely|hot|unknown)(\.|$)')
+
+if [ -n "$bad_symbols" ]; then
+	echo "$bad_symbols" | while read -r sym; do
+		echo "$objfile: error: $sym() function name creates ambiguity with -ffunction-sections" >&2
+	done
+	exit 1
+fi
+
+exit 0
diff --git a/scripts/faddr2line b/scripts/faddr2line
index 1fa6beef9f97..622875396bcf 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # SPDX-License-Identifier: GPL-2.0
 #
 # Translate stack dump function offsets.
@@ -76,6 +76,10 @@ ADDR2LINE="${UTIL_PREFIX}addr2line${UTIL_SUFFIX}"
 AWK="awk"
 GREP="grep"
 
+# Enforce ASCII-only output from tools like readelf
+# ensuring sed processes strings correctly.
+export LANG=C
+
 command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed"
 command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed"
 command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed"
@@ -107,14 +111,19 @@ find_dir_prefix() {
 
 run_readelf() {
 	local objfile=$1
-	local out=$(${READELF} --file-header --section-headers --symbols --wide $objfile)
+	local tmpfile
+	tmpfile=$(mktemp)
+
+	${READELF} --file-header --section-headers --symbols --wide "$objfile" > "$tmpfile"
 
 	# This assumes that readelf first prints the file header, then the section headers, then the symbols.
 	# Note: It seems that GNU readelf does not prefix section headers with the "There are X section headers"
 	# line when multiple options are given, so let's also match with the "Section Headers:" line.
-	ELF_FILEHEADER=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/q;p')
-	ELF_SECHEADERS=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/,$p' | sed -n '/Symbol table .* contains [0-9]* entries:/q;p')
-	ELF_SYMS=$(echo "${out}" | sed -n '/Symbol table .* contains [0-9]* entries:/,$p')
+	ELF_FILEHEADER=$(sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/q;p' "$tmpfile")
+	ELF_SECHEADERS=$(sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/,$p' "$tmpfile" | sed -n '/Symbol table .* contains [0-9]* entries:/q;p')
+	ELF_SYMS=$(sed -n '/Symbol table .* contains [0-9]* entries:/,$p' "$tmpfile")
+
+	rm -f -- "$tmpfile"
 }
 
 check_vmlinux() {
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 433849ff7529..2df714ba51a9 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -60,7 +60,8 @@ vmlinux_link()
 	# skip output file argument
 	shift
 
-	if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
+	if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT ||
+	   is_enabled CONFIG_KLP_BUILD; then
 		# Use vmlinux.o instead of performing the slow LTO link again.
 		objs=vmlinux.o
 		libs=
diff --git a/scripts/livepatch/fix-patch-lines b/scripts/livepatch/fix-patch-lines
new file mode 100755
index 000000000000..fa7d4f6592e6
--- /dev/null
+++ b/scripts/livepatch/fix-patch-lines
@@ -0,0 +1,79 @@
+#!/usr/bin/awk -f
+# SPDX-License-Identifier: GPL-2.0
+#
+# Use #line directives to preserve original __LINE__ numbers across patches to
+# avoid unwanted compilation changes.
+
+BEGIN {
+	in_hunk = 0
+	skip    = 0
+}
+
+/^--- / {
+	skip = $2 !~ /\.(c|h)$/
+	print
+	next
+}
+
+/^@@/ {
+	if (skip) {
+		print
+		next
+	}
+
+	in_hunk = 1
+
+	# @@ -1,3 +1,4 @@:
+	#   1: line number in old file
+	#   3: how many lines the hunk covers in old file
+	#   1: line number in new file
+	#   4: how many lines the hunk covers in new file
+
+	match($0, /^@@ -([0-9]+)(,([0-9]+))? \+([0-9]+)(,([0-9]+))? @@/, m)
+
+	# Set 'cur' to the old file's line number at the start of the hunk.  It
+	# gets incremented for every context line and every line removal, so
+	# that it always represents the old file's current line number.
+	cur = m[1]
+
+	# last = last line number of current hunk
+	last = cur + (m[3] ? m[3] : 1) - 1
+
+	need_line_directive = 0
+
+	print
+	next
+}
+
+{
+	if (skip || !in_hunk || $0 ~ /^\\ No newline at end of file/) {
+		print
+		next
+	}
+
+	# change line
+	if ($0 ~ /^[+-]/) {
+		# inject #line after this group of changes
+		need_line_directive = 1
+
+		if ($0 ~ /^-/)
+			cur++
+
+		print
+		next
+	}
+
+	# If this is the first context line after a group of changes, inject
+	# the #line directive to force the compiler to correct the line
+	# numbering to match the original file.
+	if (need_line_directive) {
+		print "+#line " cur
+		need_line_directive = 0
+	}
+
+	if (cur == last)
+		in_hunk = 0
+
+	cur++
+	print
+}
diff --git a/scripts/livepatch/init.c b/scripts/livepatch/init.c
new file mode 100644
index 000000000000..2274d8f5a482
--- /dev/null
+++ b/scripts/livepatch/init.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Init code for a livepatch kernel module
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/livepatch.h>
+
+extern struct klp_object_ext __start_klp_objects[];
+extern struct klp_object_ext __stop_klp_objects[];
+
+static struct klp_patch *patch;
+
+static int __init livepatch_mod_init(void)
+{
+	struct klp_object *objs;
+	unsigned int nr_objs;
+	int ret;
+
+	nr_objs = __stop_klp_objects - __start_klp_objects;
+
+	if (!nr_objs) {
+		pr_err("nothing to patch!\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	patch = kzalloc(sizeof(*patch), GFP_KERNEL);
+	if (!patch) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	objs = kzalloc(sizeof(struct klp_object) * (nr_objs + 1),  GFP_KERNEL);
+	if (!objs) {
+		ret = -ENOMEM;
+		goto err_free_patch;
+	}
+
+	for (int i = 0; i < nr_objs; i++) {
+		struct klp_object_ext *obj_ext = __start_klp_objects + i;
+		struct klp_func_ext *funcs_ext = obj_ext->funcs;
+		unsigned int nr_funcs = obj_ext->nr_funcs;
+		struct klp_func *funcs = objs[i].funcs;
+		struct klp_object *obj = objs + i;
+
+		funcs = kzalloc(sizeof(struct klp_func) * (nr_funcs + 1), GFP_KERNEL);
+		if (!funcs) {
+			ret = -ENOMEM;
+			for (int j = 0; j < i; j++)
+				kfree(objs[i].funcs);
+			goto err_free_objs;
+		}
+
+		for (int j = 0; j < nr_funcs; j++) {
+			funcs[j].old_name   = funcs_ext[j].old_name;
+			funcs[j].new_func   = funcs_ext[j].new_func;
+			funcs[j].old_sympos = funcs_ext[j].sympos;
+		}
+
+		obj->name = obj_ext->name;
+		obj->funcs = funcs;
+
+		memcpy(&obj->callbacks, &obj_ext->callbacks, sizeof(struct klp_callbacks));
+	}
+
+	patch->mod = THIS_MODULE;
+	patch->objs = objs;
+
+	/* TODO patch->states */
+
+#ifdef KLP_NO_REPLACE
+	patch->replace = false;
+#else
+	patch->replace = true;
+#endif
+
+	return klp_enable_patch(patch);
+
+err_free_objs:
+	kfree(objs);
+err_free_patch:
+	kfree(patch);
+err:
+	return ret;
+}
+
+static void __exit livepatch_mod_exit(void)
+{
+	unsigned int nr_objs;
+
+	nr_objs = __stop_klp_objects - __start_klp_objects;
+
+	for (int i = 0; i < nr_objs; i++)
+		kfree(patch->objs[i].funcs);
+
+	kfree(patch->objs);
+	kfree(patch);
+}
+
+module_init(livepatch_mod_init);
+module_exit(livepatch_mod_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_DESCRIPTION("Livepatch module");
diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
new file mode 100755
index 000000000000..882272120c9e
--- /dev/null
+++ b/scripts/livepatch/klp-build
@@ -0,0 +1,831 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Build a livepatch module
+
+# shellcheck disable=SC1090,SC2155
+
+if (( BASH_VERSINFO[0]  < 4 || \
+     (BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] < 4) )); then
+		echo "error: this script requires bash 4.4+" >&2
+	exit 1
+fi
+
+set -o errexit
+set -o errtrace
+set -o pipefail
+set -o nounset
+
+# Allow doing 'cmd | mapfile -t array' instead of 'mapfile -t array < <(cmd)'.
+# This helps keep execution in pipes so pipefail+errexit can catch errors.
+shopt -s lastpipe
+
+unset DEBUG_CLONE DIFF_CHECKSUM SKIP_CLEANUP XTRACE
+
+REPLACE=1
+SHORT_CIRCUIT=0
+JOBS="$(getconf _NPROCESSORS_ONLN)"
+VERBOSE="-s"
+shopt -o xtrace | grep -q 'on' && XTRACE=1
+
+# Avoid removing the previous $TMP_DIR until args have been fully processed.
+KEEP_TMP=1
+
+SCRIPT="$(basename "$0")"
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+FIX_PATCH_LINES="$SCRIPT_DIR/fix-patch-lines"
+
+SRC="$(pwd)"
+OBJ="$(pwd)"
+
+CONFIG="$OBJ/.config"
+TMP_DIR="$OBJ/klp-tmp"
+
+ORIG_DIR="$TMP_DIR/orig"
+PATCHED_DIR="$TMP_DIR/patched"
+DIFF_DIR="$TMP_DIR/diff"
+KMOD_DIR="$TMP_DIR/kmod"
+
+STASH_DIR="$TMP_DIR/stash"
+TIMESTAMP="$TMP_DIR/timestamp"
+PATCH_TMP_DIR="$TMP_DIR/tmp"
+
+KLP_DIFF_LOG="$DIFF_DIR/diff.log"
+
+grep0() {
+	command grep "$@" || true
+}
+
+status() {
+	echo "$*"
+}
+
+warn() {
+	echo "error: $SCRIPT: $*" >&2
+}
+
+die() {
+	warn "$@"
+	exit 1
+}
+
+declare -a STASHED_FILES
+
+stash_file() {
+	local file="$1"
+	local rel_file="${file#"$SRC"/}"
+
+	[[ ! -e "$file" ]] && die "no file to stash: $file"
+
+	mkdir -p "$STASH_DIR/$(dirname "$rel_file")"
+	cp -f "$file" "$STASH_DIR/$rel_file"
+
+	STASHED_FILES+=("$rel_file")
+}
+
+restore_files() {
+	local file
+
+	for file in "${STASHED_FILES[@]}"; do
+		mv -f "$STASH_DIR/$file" "$SRC/$file" || warn "can't restore file: $file"
+	done
+
+	STASHED_FILES=()
+}
+
+cleanup() {
+	set +o nounset
+	revert_patches "--recount"
+	restore_files
+	[[ "$KEEP_TMP" -eq 0 ]] && rm -rf "$TMP_DIR"
+	return 0
+}
+
+trap_err() {
+	warn "line ${BASH_LINENO[0]}: '$BASH_COMMAND'"
+}
+
+trap cleanup  EXIT INT TERM HUP
+trap trap_err ERR
+
+__usage() {
+	cat <<EOF
+Usage: $SCRIPT [OPTIONS] PATCH_FILE(s)
+Generate a livepatch module.
+
+Options:
+   -f, --show-first-changed	Show address of first changed instruction
+   -j, --jobs=<jobs>		Build jobs to run simultaneously [default: $JOBS]
+   -o, --output=<file.ko>	Output file [default: livepatch-<patch-name>.ko]
+       --no-replace		Disable livepatch atomic replace
+   -v, --verbose		Pass V=1 to kernel/module builds
+
+Advanced Options:
+   -d, --debug			Show symbol/reloc cloning decisions
+   -S, --short-circuit=STEP	Start at build step (requires prior --keep-tmp)
+				   1|orig	Build original kernel (default)
+				   2|patched	Build patched kernel
+				   3|diff	Diff objects
+				   4|kmod	Build patch module
+   -T, --keep-tmp		Preserve tmp dir on exit
+
+EOF
+}
+
+usage() {
+	__usage >&2
+}
+
+process_args() {
+	local keep_tmp=0
+	local short
+	local long
+	local args
+
+	short="hfj:o:vdS:T"
+	long="help,show-first-changed,jobs:,output:,no-replace,verbose,debug,short-circuit:,keep-tmp"
+
+	args=$(getopt --options "$short" --longoptions "$long" -- "$@") || {
+		echo; usage; exit
+	}
+	eval set -- "$args"
+
+	while true; do
+		case "$1" in
+			-h | --help)
+				usage
+				exit 0
+				;;
+			-f | --show-first-changed)
+				DIFF_CHECKSUM=1
+				shift
+				;;
+			-j | --jobs)
+				JOBS="$2"
+				shift 2
+				;;
+			-o | --output)
+				[[ "$2" != *.ko ]] && die "output filename should end with .ko"
+				OUTFILE="$2"
+				NAME="$(basename "$OUTFILE")"
+				NAME="${NAME%.ko}"
+				NAME="$(module_name_string "$NAME")"
+				shift 2
+				;;
+			--no-replace)
+				REPLACE=0
+				shift
+				;;
+			-v | --verbose)
+				VERBOSE="V=1"
+				shift
+				;;
+			-d | --debug)
+				DEBUG_CLONE=1
+				keep_tmp=1
+				shift
+				;;
+			-S | --short-circuit)
+				[[ ! -d "$TMP_DIR" ]] && die "--short-circuit requires preserved klp-tmp dir"
+				keep_tmp=1
+				case "$2" in
+					1 | orig)	SHORT_CIRCUIT=1; ;;
+					2 | patched)	SHORT_CIRCUIT=2; ;;
+					3 | diff)	SHORT_CIRCUIT=3; ;;
+					4 | mod)	SHORT_CIRCUIT=4; ;;
+					*)		die "invalid short-circuit step '$2'" ;;
+				esac
+				shift 2
+				;;
+			-T | --keep-tmp)
+				keep_tmp=1
+				shift
+				;;
+			--)
+				shift
+				break
+				;;
+			*)
+				usage
+				exit 1
+				;;
+		esac
+	done
+
+	if [[ $# -eq 0 ]]; then
+		usage
+		exit 1
+	fi
+
+	KEEP_TMP="$keep_tmp"
+	PATCHES=("$@")
+}
+
+# temporarily disable xtrace for especially verbose code
+xtrace_save() {
+	[[ -v XTRACE ]] && set +x
+	return 0
+}
+
+xtrace_restore() {
+	[[ -v XTRACE ]] && set -x
+	return 0
+}
+
+validate_config() {
+	xtrace_save "reading .config"
+	source "$CONFIG" || die "no .config file in $(dirname "$CONFIG")"
+	xtrace_restore
+
+	[[ -v CONFIG_LIVEPATCH ]] ||			\
+		die "CONFIG_LIVEPATCH not enabled"
+
+	[[ -v CONFIG_KLP_BUILD ]] ||			\
+		die "CONFIG_KLP_BUILD not enabled"
+
+	[[ -v CONFIG_GCC_PLUGIN_LATENT_ENTROPY ]] &&	\
+		die "kernel option 'CONFIG_GCC_PLUGIN_LATENT_ENTROPY' not supported"
+
+	[[ -v CONFIG_GCC_PLUGIN_RANDSTRUCT ]] &&	\
+		die "kernel option 'CONFIG_GCC_PLUGIN_RANDSTRUCT' not supported"
+
+	return 0
+}
+
+# Only allow alphanumerics and '_' and '-' in the module name.  Everything else
+# is replaced with '-'.  Also truncate to 55 chars so the full name + NUL
+# terminator fits in the kernel's 56-byte module name array.
+module_name_string() {
+	echo "${1//[^a-zA-Z0-9_-]/-}" | cut -c 1-55
+}
+
+# If the module name wasn't specified on the cmdline with --output, give it a
+# name based on the patch name.
+set_module_name() {
+	[[ -v NAME ]] && return 0
+
+	if [[ "${#PATCHES[@]}" -eq 1 ]]; then
+		NAME="$(basename "${PATCHES[0]}")"
+		NAME="${NAME%.*}"
+	else
+		NAME="patch"
+	fi
+
+	NAME="livepatch-$NAME"
+	NAME="$(module_name_string "$NAME")"
+
+	OUTFILE="$NAME.ko"
+}
+
+# Hardcode the value printed by the localversion script to prevent patch
+# application from appending it with '+' due to a dirty git working tree.
+set_kernelversion() {
+	local file="$SRC/scripts/setlocalversion"
+	local localversion
+
+	stash_file "$file"
+
+	localversion="$(cd "$SRC" && make --no-print-directory kernelversion)"
+	localversion="$(cd "$SRC" && KERNELVERSION="$localversion" ./scripts/setlocalversion)"
+	[[ -z "$localversion" ]] && die "setlocalversion failed"
+
+	sed -i "2i echo $localversion; exit 0" scripts/setlocalversion
+}
+
+get_patch_files() {
+	local patch="$1"
+
+	grep0 -E '^(--- |\+\+\+ )' "$patch"			\
+		| gawk '{print $2}'				\
+		| sed 's|^[^/]*/||'				\
+		| sort -u
+}
+
+# Make sure git re-stats the changed files
+git_refresh() {
+	local patch="$1"
+	local files=()
+
+	[[ ! -e "$SRC/.git" ]] && return
+
+	get_patch_files "$patch" | mapfile -t files
+
+	(
+		cd "$SRC"
+		git update-index -q --refresh -- "${files[@]}"
+	)
+}
+
+check_unsupported_patches() {
+	local patch
+
+	for patch in "${PATCHES[@]}"; do
+		local files=()
+
+		get_patch_files "$patch" | mapfile -t files
+
+		for file in "${files[@]}"; do
+			case "$file" in
+				lib/*|*.S)
+					die "unsupported patch to $file"
+					;;
+			esac
+		done
+	done
+}
+
+apply_patch() {
+	local patch="$1"
+	shift
+	local extra_args=("$@")
+
+	[[ ! -f "$patch" ]] && die "$patch doesn't exist"
+
+	(
+		cd "$SRC"
+
+		# The sed strips the version signature from 'git format-patch',
+		# otherwise 'git apply --recount' warns.
+		sed -n '/^-- /q;p' "$patch" |
+			git apply "${extra_args[@]}"
+	)
+
+	APPLIED_PATCHES+=("$patch")
+}
+
+revert_patch() {
+	local patch="$1"
+	shift
+	local extra_args=("$@")
+	local tmp=()
+
+	(
+		cd "$SRC"
+
+		sed -n '/^-- /q;p' "$patch" |
+			git apply --reverse "${extra_args[@]}"
+	)
+	git_refresh "$patch"
+
+	for p in "${APPLIED_PATCHES[@]}"; do
+		[[ "$p" == "$patch" ]] && continue
+		tmp+=("$p")
+	done
+
+	APPLIED_PATCHES=("${tmp[@]}")
+}
+
+apply_patches() {
+	local patch
+
+	for patch in "${PATCHES[@]}"; do
+		apply_patch "$patch"
+	done
+}
+
+revert_patches() {
+	local extra_args=("$@")
+	local patches=("${APPLIED_PATCHES[@]}")
+
+	for (( i=${#patches[@]}-1 ; i>=0 ; i-- )) ; do
+		revert_patch "${patches[$i]}" "${extra_args[@]}"
+	done
+
+	APPLIED_PATCHES=()
+}
+
+validate_patches() {
+	check_unsupported_patches
+	apply_patches
+	revert_patches
+}
+
+do_init() {
+	# We're not yet smart enough to handle anything other than in-tree
+	# builds in pwd.
+	[[ ! "$SRC" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
+	[[ ! "$OBJ" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
+
+	(( SHORT_CIRCUIT <= 1 )) && rm -rf "$TMP_DIR"
+	mkdir -p "$TMP_DIR"
+
+	APPLIED_PATCHES=()
+
+	[[ -x "$FIX_PATCH_LINES" ]] || die "can't find fix-patch-lines"
+
+	validate_config
+	set_module_name
+	set_kernelversion
+}
+
+# Refresh the patch hunk headers, specifically the line numbers and counts.
+refresh_patch() {
+	local patch="$1"
+	local tmpdir="$PATCH_TMP_DIR"
+	local files=()
+
+	rm -rf "$tmpdir"
+	mkdir -p "$tmpdir/a"
+	mkdir -p "$tmpdir/b"
+
+	# Get all source files affected by the patch
+	get_patch_files "$patch" | mapfile -t files
+
+	# Copy orig source files to 'a'
+	( cd "$SRC" && echo "${files[@]}" | xargs cp --parents --target-directory="$tmpdir/a" )
+
+	# Copy patched source files to 'b'
+	apply_patch "$patch" --recount
+	( cd "$SRC" && echo "${files[@]}" | xargs cp --parents --target-directory="$tmpdir/b" )
+	revert_patch "$patch" --recount
+
+	# Diff 'a' and 'b' to make a clean patch
+	( cd "$tmpdir" && git diff --no-index --no-prefix a b > "$patch" ) || true
+}
+
+# Copy the patches to a temporary directory, fix their lines so as not to
+# affect the __LINE__ macro for otherwise unchanged functions further down the
+# file, and update $PATCHES to point to the fixed patches.
+fix_patches() {
+	local idx
+	local i
+
+	rm -f "$TMP_DIR"/*.patch
+
+	idx=0001
+	for i in "${!PATCHES[@]}"; do
+		local old_patch="${PATCHES[$i]}"
+		local tmp_patch="$TMP_DIR/tmp.patch"
+		local patch="${PATCHES[$i]}"
+		local new_patch
+
+		new_patch="$TMP_DIR/$idx-fixed-$(basename "$patch")"
+
+		cp -f "$old_patch" "$tmp_patch"
+		refresh_patch "$tmp_patch"
+		"$FIX_PATCH_LINES" "$tmp_patch" > "$new_patch"
+		refresh_patch "$new_patch"
+
+		PATCHES[i]="$new_patch"
+
+		rm -f "$tmp_patch"
+		idx=$(printf "%04d" $(( 10#$idx + 1 )))
+	done
+}
+
+clean_kernel() {
+	local cmd=()
+
+	cmd=("make")
+	cmd+=("--silent")
+	cmd+=("-j$JOBS")
+	cmd+=("clean")
+
+	(
+		cd "$SRC"
+		"${cmd[@]}"
+	)
+}
+
+build_kernel() {
+	local log="$TMP_DIR/build.log"
+	local objtool_args=()
+	local cmd=()
+
+	objtool_args=("--checksum")
+
+	cmd=("make")
+
+	# When a patch to a kernel module references a newly created unexported
+	# symbol which lives in vmlinux or another kernel module, the patched
+	# kernel build fails with the following error:
+	#
+	#   ERROR: modpost: "klp_string" [fs/xfs/xfs.ko] undefined!
+	#
+	# The undefined symbols are working as designed in that case.  They get
+	# resolved later when the livepatch module build link pulls all the
+	# disparate objects together into the same kernel module.
+	#
+	# It would be good to have a way to tell modpost to skip checking for
+	# undefined symbols altogether.  For now, just convert the error to a
+	# warning with KBUILD_MODPOST_WARN, and grep out the warning to avoid
+	# confusing the user.
+	#
+	cmd+=("KBUILD_MODPOST_WARN=1")
+
+	cmd+=("$VERBOSE")
+	cmd+=("-j$JOBS")
+	cmd+=("KCFLAGS=-ffunction-sections -fdata-sections")
+	cmd+=("OBJTOOL_ARGS=${objtool_args[*]}")
+	cmd+=("vmlinux")
+	cmd+=("modules")
+
+	(
+		cd "$SRC"
+		"${cmd[@]}"							\
+			1> >(tee -a "$log")					\
+			2> >(tee -a "$log" | grep0 -v "modpost.*undefined!" >&2)
+	)
+}
+
+find_objects() {
+	local opts=("$@")
+
+	# Find root-level vmlinux.o and non-root-level .ko files,
+	# excluding klp-tmp/ and .git/
+	find "$OBJ" \( -path "$TMP_DIR" -o -path "$OBJ/.git" -o	-regex "$OBJ/[^/][^/]*\.ko" \) -prune -o \
+		    -type f "${opts[@]}"				\
+		    \( -name "*.ko" -o -path "$OBJ/vmlinux.o" \)	\
+		    -printf '%P\n'
+}
+
+# Copy all .o archives to $ORIG_DIR
+copy_orig_objects() {
+	local files=()
+
+	rm -rf "$ORIG_DIR"
+	mkdir -p "$ORIG_DIR"
+
+	find_objects | mapfile -t files
+
+	xtrace_save "copying orig objects"
+	for _file in "${files[@]}"; do
+		local rel_file="${_file/.ko/.o}"
+		local file="$OBJ/$rel_file"
+		local file_dir="$(dirname "$file")"
+		local orig_file="$ORIG_DIR/$rel_file"
+		local orig_dir="$(dirname "$orig_file")"
+		local cmd_file="$file_dir/.$(basename "$file").cmd"
+
+		[[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file"
+
+		mkdir -p "$orig_dir"
+		cp -f "$file" "$orig_dir"
+		[[ -e "$cmd_file" ]] && cp -f "$cmd_file" "$orig_dir"
+	done
+	xtrace_restore
+
+	mv -f "$TMP_DIR/build.log" "$ORIG_DIR"
+	touch "$TIMESTAMP"
+}
+
+# Copy all changed objects to $PATCHED_DIR
+copy_patched_objects() {
+	local files=()
+	local opts=()
+	local found=0
+
+	rm -rf "$PATCHED_DIR"
+	mkdir -p "$PATCHED_DIR"
+
+	# Note this doesn't work with some configs, thus the 'cmp' below.
+	opts=("-newer")
+	opts+=("$TIMESTAMP")
+
+	find_objects "${opts[@]}" | mapfile -t files
+
+	xtrace_save "copying changed objects"
+	for _file in "${files[@]}"; do
+		local rel_file="${_file/.ko/.o}"
+		local file="$OBJ/$rel_file"
+		local orig_file="$ORIG_DIR/$rel_file"
+		local patched_file="$PATCHED_DIR/$rel_file"
+		local patched_dir="$(dirname "$patched_file")"
+
+		[[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file"
+
+		cmp -s "$orig_file" "$file" && continue
+
+		mkdir -p "$patched_dir"
+		cp -f "$file" "$patched_dir"
+		found=1
+	done
+	xtrace_restore
+
+	(( found == 0 )) && die "no changes detected"
+
+	mv -f "$TMP_DIR/build.log" "$PATCHED_DIR"
+}
+
+# Diff changed objects, writing output object to $DIFF_DIR
+diff_objects() {
+	local log="$KLP_DIFF_LOG"
+	local files=()
+	local opts=()
+
+	rm -rf "$DIFF_DIR"
+	mkdir -p "$DIFF_DIR"
+
+	find "$PATCHED_DIR" -type f -name "*.o" | mapfile -t files
+	[[ ${#files[@]} -eq 0 ]] && die "no changes detected"
+
+	[[ -v DEBUG_CLONE ]] && opts=("--debug")
+
+	# Diff all changed objects
+	for file in "${files[@]}"; do
+		local rel_file="${file#"$PATCHED_DIR"/}"
+		local orig_file="$rel_file"
+		local patched_file="$PATCHED_DIR/$rel_file"
+		local out_file="$DIFF_DIR/$rel_file"
+		local filter=()
+		local cmd=()
+
+		mkdir -p "$(dirname "$out_file")"
+
+		cmd=("$SRC/tools/objtool/objtool")
+		cmd+=("klp")
+		cmd+=("diff")
+		(( ${#opts[@]} > 0 )) && cmd+=("${opts[@]}")
+		cmd+=("$orig_file")
+		cmd+=("$patched_file")
+		cmd+=("$out_file")
+
+		if [[ -v DIFF_CHECKSUM ]]; then
+			filter=("grep0")
+			filter+=("-Ev")
+			filter+=("DEBUG: .*checksum: ")
+		else
+			filter=("cat")
+		fi
+
+		(
+			cd "$ORIG_DIR"
+			"${cmd[@]}"							\
+				1> >(tee -a "$log")					\
+				2> >(tee -a "$log" | "${filter[@]}" >&2) ||		\
+				die "objtool klp diff failed"
+		)
+	done
+}
+
+# For each changed object, run objtool with --debug-checksum to get the
+# per-instruction checksums, and then diff those to find the first changed
+# instruction for each function.
+diff_checksums() {
+	local orig_log="$ORIG_DIR/checksum.log"
+	local patched_log="$PATCHED_DIR/checksum.log"
+	local -A funcs
+	local cmd=()
+	local line
+	local file
+	local func
+
+	gawk '/\.o: changed function: / {
+		sub(/:$/, "", $1)
+		print $1, $NF
+	}' "$KLP_DIFF_LOG" | mapfile -t lines
+
+	for line in "${lines[@]}"; do
+		read -r file func <<< "$line"
+		if [[ ! -v funcs["$file"] ]]; then
+			funcs["$file"]="$func"
+		else
+			funcs["$file"]+=" $func"
+		fi
+	done
+
+	cmd=("$SRC/tools/objtool/objtool")
+	cmd+=("--checksum")
+	cmd+=("--link")
+	cmd+=("--dry-run")
+
+	for file in "${!funcs[@]}"; do
+		local opt="--debug-checksum=${funcs[$file]// /,}"
+
+		(
+			cd "$ORIG_DIR"
+			"${cmd[@]}" "$opt" "$file" &> "$orig_log" || \
+				( cat "$orig_log" >&2; die "objtool --debug-checksum failed" )
+
+			cd "$PATCHED_DIR"
+			"${cmd[@]}" "$opt" "$file" &> "$patched_log" ||	\
+				( cat "$patched_log" >&2; die "objtool --debug-checksum failed" )
+		)
+
+		for func in ${funcs[$file]}; do
+			diff <( grep0 -E "^DEBUG: .*checksum: $func " "$orig_log"    | sed "s|$ORIG_DIR/||")	\
+			     <( grep0 -E "^DEBUG: .*checksum: $func " "$patched_log" | sed "s|$PATCHED_DIR/||")	\
+				| gawk '/^< DEBUG: / {
+					gsub(/:/, "")
+					printf "%s: %s: %s\n", $3, $5, $6
+					exit
+			}' || true
+		done
+	done
+}
+
+# Build and post-process livepatch module in $KMOD_DIR
+build_patch_module() {
+	local makefile="$KMOD_DIR/Kbuild"
+	local log="$KMOD_DIR/build.log"
+	local kmod_file
+	local cflags=()
+	local files=()
+	local cmd=()
+
+	rm -rf "$KMOD_DIR"
+	mkdir -p "$KMOD_DIR"
+
+	cp -f "$SRC/scripts/livepatch/init.c" "$KMOD_DIR"
+
+	echo "obj-m := $NAME.o" > "$makefile"
+	echo -n "$NAME-y := init.o" >> "$makefile"
+
+	find "$DIFF_DIR" -type f -name "*.o" | mapfile -t files
+	[[ ${#files[@]} -eq 0 ]] && die "no changes detected"
+
+	for file in "${files[@]}"; do
+		local rel_file="${file#"$DIFF_DIR"/}"
+		local orig_file="$ORIG_DIR/$rel_file"
+		local orig_dir="$(dirname "$orig_file")"
+		local kmod_file="$KMOD_DIR/$rel_file"
+		local kmod_dir="$(dirname "$kmod_file")"
+		local cmd_file="$orig_dir/.$(basename "$file").cmd"
+
+		mkdir -p "$kmod_dir"
+		cp -f "$file" "$kmod_dir"
+		[[ -e "$cmd_file" ]] && cp -f "$cmd_file" "$kmod_dir"
+
+		# Tell kbuild this is a prebuilt object
+		cp -f "$file" "${kmod_file}_shipped"
+
+		echo -n " $rel_file" >> "$makefile"
+	done
+
+	echo >> "$makefile"
+
+	cflags=("-ffunction-sections")
+	cflags+=("-fdata-sections")
+	[[ $REPLACE -eq 0 ]] && cflags+=("-DKLP_NO_REPLACE")
+
+	cmd=("make")
+	cmd+=("$VERBOSE")
+	cmd+=("-j$JOBS")
+	cmd+=("--directory=.")
+	cmd+=("M=$KMOD_DIR")
+	cmd+=("KCFLAGS=${cflags[*]}")
+
+	# Build a "normal" kernel module with init.c and the diffed objects
+	(
+		cd "$SRC"
+		"${cmd[@]}"							\
+			1> >(tee -a "$log")					\
+			2> >(tee -a "$log" >&2)
+	)
+
+	kmod_file="$KMOD_DIR/$NAME.ko"
+
+	# Save off the intermediate binary for debugging
+	cp -f "$kmod_file" "$kmod_file.orig"
+
+	# Work around issue where slight .config change makes corrupt BTF
+	objcopy --remove-section=.BTF "$kmod_file"
+
+	# Fix (and work around) linker wreckage for klp syms / relocs
+	"$SRC/tools/objtool/objtool" klp post-link "$kmod_file" || die "objtool klp post-link failed"
+
+	cp -f "$kmod_file" "$OUTFILE"
+}
+
+
+################################################################################
+
+process_args "$@"
+do_init
+
+if (( SHORT_CIRCUIT <= 1 )); then
+	status "Validating patch(es)"
+	validate_patches
+	status "Building original kernel"
+	clean_kernel
+	build_kernel
+	status "Copying original object files"
+	copy_orig_objects
+fi
+
+if (( SHORT_CIRCUIT <= 2 )); then
+	status "Fixing patch(es)"
+	fix_patches
+	apply_patches
+	status "Building patched kernel"
+	build_kernel
+	revert_patches
+	status "Copying patched object files"
+	copy_patched_objects
+fi
+
+if (( SHORT_CIRCUIT <= 3 )); then
+	status "Diffing objects"
+	diff_objects
+	if [[ -v DIFF_CHECKSUM ]]; then
+		status "Finding first changed instructions"
+		diff_checksums
+	fi
+fi
+
+if (( SHORT_CIRCUIT <= 4 )); then
+	status "Building patch module: $OUTFILE"
+	build_patch_module
+fi
+
+status "SUCCESS"
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 47c8aa2a6939..755b842f1f9b 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -606,6 +606,11 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 		    strstarts(symname, "_savevr_") ||
 		    strcmp(symname, ".TOC.") == 0)
 			return 1;
+
+	/* ignore linker-created section bounds variables */
+	if (strstarts(symname, "__start_") || strstarts(symname, "__stop_"))
+		return 1;
+
 	/* Do not ignore this symbol */
 	return 0;
 }
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index ee79c41059f3..3037d5e5527c 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -34,16 +34,22 @@ SECTIONS {
 
 	__patchable_function_entries : { *(__patchable_function_entries) }
 
+	__klp_funcs		0: ALIGN(8) { KEEP(*(__klp_funcs)) }
+
+	__klp_objects		0: ALIGN(8) {
+		__start_klp_objects = .;
+		KEEP(*(__klp_objects))
+		__stop_klp_objects = .;
+	}
+
 #ifdef CONFIG_ARCH_USES_CFI_TRAPS
-	__kcfi_traps 		: { KEEP(*(.kcfi_traps)) }
+	__kcfi_traps		: { KEEP(*(.kcfi_traps)) }
 #endif
 
-#ifdef CONFIG_LTO_CLANG
-	/*
-	 * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and
-	 * -ffunction-sections, which increases the size of the final module.
-	 * Merge the split sections in the final binary.
-	 */
+	.text : {
+		*(.text .text.[0-9a-zA-Z_]*)
+	}
+
 	.bss : {
 		*(.bss .bss.[0-9a-zA-Z_]*)
 		*(.bss..L*)
@@ -58,7 +64,7 @@ SECTIONS {
 		*(.rodata .rodata.[0-9a-zA-Z_]*)
 		*(.rodata..L*)
 	}
-#endif
+
 	MOD_SEPARATE_CODETAG_SECTIONS()
 }
 
diff --git a/scripts/syscall.tbl b/scripts/syscall.tbl
index d1ae5e92c615..e74868be513c 100644
--- a/scripts/syscall.tbl
+++ b/scripts/syscall.tbl
@@ -410,3 +410,4 @@
 467	common	open_tree_attr			sys_open_tree_attr
 468	common	file_getattr			sys_file_getattr
 469	common	file_setattr			sys_file_setattr
+470	common	listns				sys_listns