1#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0
3
4TARGET=$1
5ARCH=$2
6SMP=$3
7PREEMPT=$4
8PREEMPT_DYNAMIC=$5
9PREEMPT_RT=$6
10CC_VERSION="$7"
11LD=$8
12
13# Do not expand names
14set -f
15
16# Fix the language to get consistent output
17LC_ALL=C
18export LC_ALL
19
20if [ -z "$KBUILD_BUILD_VERSION" ]; then
21	VERSION=$(cat .version 2>/dev/null || echo 1)
22else
23	VERSION=$KBUILD_BUILD_VERSION
24fi
25
26if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
27	TIMESTAMP=`date`
28else
29	TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
30fi
31if test -z "$KBUILD_BUILD_USER"; then
32	LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
33else
34	LINUX_COMPILE_BY=$KBUILD_BUILD_USER
35fi
36if test -z "$KBUILD_BUILD_HOST"; then
37	LINUX_COMPILE_HOST=`uname -n`
38else
39	LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
40fi
41
42UTS_VERSION="#$VERSION"
43CONFIG_FLAGS=""
44if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
45
46if [ -n "$PREEMPT_RT" ] ; then
47	CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"
48elif [ -n "$PREEMPT_DYNAMIC" ] ; then
49	CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_DYNAMIC"
50elif [ -n "$PREEMPT" ] ; then
51	CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"
52fi
53
54# Truncate to maximum length
55UTS_LEN=64
56UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)"
57
58# Generate a temporary compile.h
59
60{ echo /\* This file is auto generated, version $VERSION \*/
61  if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi
62
63  echo \#define UTS_MACHINE \"$ARCH\"
64
65  echo \#define UTS_VERSION \"$UTS_VERSION\"
66
67  printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY"
68  echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\"
69
70  LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
71		      | sed 's/[[:space:]]*$//')
72  printf '#define LINUX_COMPILER "%s"\n' "$CC_VERSION, $LD_VERSION"
73} > .tmpcompile
74
75# Only replace the real compile.h if the new one is different,
76# in order to preserve the timestamp and avoid unnecessary
77# recompilations.
78# We don't consider the file changed if only the date/time changed,
79# unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for
80# reproducible builds with that value referring to a commit timestamp).
81# A kernel config change will increase the generation number, thus
82# causing compile.h to be updated (including date/time) due to the
83# changed comment in the
84# first line.
85
86if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
87   IGNORE_PATTERN="UTS_VERSION"
88else
89   IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED"
90fi
91
92if [ -r $TARGET ] && \
93      grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \
94      grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \
95      cmp -s .tmpver.1 .tmpver.2; then
96   rm -f .tmpcompile
97else
98   echo "  UPD     $TARGET"
99   mv -f .tmpcompile $TARGET
100fi
101rm -f .tmpver.1 .tmpver.2
102