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kpatch-build: add cross-compilation support (#1224 fix) #1233

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Merged
merged 2 commits into from
Feb 14, 2022
Merged

kpatch-build: add cross-compilation support (#1224 fix) #1233

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fd0457b
kpatch-build: add cross-compilation support
omatiusha Jan 12, 2022
0decc79
kpatch-build: introduce ability to ignore distro-specific checks
omatiusha Jan 18, 2022
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2 changes: 1 addition & 1 deletion kpatch-build/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ else ifeq ($(ARCH),ppc64le)
SOURCES += gcc-plugins/ppc64le-plugin.c
PLUGIN = gcc-plugins/ppc64le-plugin.so
TARGETS += $(PLUGIN)
GCC_PLUGINS_DIR := $(shell gcc -print-file-name=plugin)
GCC_PLUGINS_DIR := $(shell $(CROSS_COMPILE)gcc -print-file-name=plugin)
PLUGIN_CFLAGS := $(filter-out -Wconversion, $(CFLAGS))
PLUGIN_CFLAGS += -shared -I$(GCC_PLUGINS_DIR)/include \
-Igcc-plugins -fPIC -fno-rtti -O2 -Wall
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45 changes: 28 additions & 17 deletions kpatch-build/kpatch-build
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Expand Up @@ -58,6 +58,13 @@ APPLIED_PATCHES=0
OOT_MODULE=
KLP_REPLACE=1

GCC="${CROSS_COMPILE:-}gcc"
CLANG="${CROSS_COMPILE:-}clang"
LD="${CROSS_COMPILE:-}ld"
LLD="${CROSS_COMPILE:-}ld.lld"
READELF="${CROSS_COMPILE:-}readelf"
OBJCOPY="${CROSS_COMPILE:-}objcopy"

warn() {
echo "ERROR: $1" >&2
}
Expand Down Expand Up @@ -267,7 +274,7 @@ find_core_symvers() {
}

gcc_version_from_file() {
readelf -p .comment "$1" | grep -m 1 -o 'GCC:.*'
"$READELF" -p .comment "$1" | grep -m 1 -o 'GCC:.*'
}
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@jpoimboe jpoimboe Jan 17, 2022

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clang_version_from_file() and clang_version_check() are missing CROSS_COMPILE.

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@jpoimboe jpoimboe Jan 17, 2022

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Also, instead of sprinkling CROSS_COMPILE everywhere, it may be cleaner to just have GCC, CLANG, READELF, OBJCOPY, LD, LD_LLD variables defined at the top of the file to include CROSS_COMPILE.

(As a further eventual cleanup we might want to just have CC and LD variables instead of GCC/CLANG/LD/LD_LLD, but that might be a little tricky since it depends on the config file, and maybe can be done later.)

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@omatiusha omatiusha Jan 18, 2022

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I do not know if these changes work with clang as well, so I can add them at our own risk


gcc_version_check() {
Expand All @@ -278,7 +285,7 @@ gcc_version_check() {
# gcc --version varies between distributions therefore extract version
# by compiling a test file and compare it to vmlinux's version.
echo 'void main(void) {}' > "$c"
out="$(gcc -c -pg -ffunction-sections -o "$o" "$c" 2>&1)"
out="$("$GCC" -c -pg -ffunction-sections -o "$o" "$c" 2>&1)"
gccver="$(gcc_version_from_file "$o")"
kgccver="$(gcc_version_from_file "$target")"

Expand All @@ -288,7 +295,7 @@ gcc_version_check() {
return 1
fi

out="$(gcc -c -gz=none -o "$o" "$c" 2>&1)"
out="$("$GCC" -c -gz=none -o "$o" "$c" 2>&1)"
if [[ -z "$out" ]]; then
DEBUG_KCFLAGS="-gz=none"
fi
Expand All @@ -308,14 +315,14 @@ gcc_version_check() {
}

clang_version_from_file() {
readelf -p .comment "$1" | grep -m 1 -Eo 'clang version [0-9.]+'
"$READELF" -p .comment "$1" | grep -m 1 -Eo 'clang version [0-9.]+'
}

clang_version_check() {
local target="$1"
local clangver kclangver

clangver=$(clang --version | grep -m 1 -Eo 'clang version [0-9.]+')
clangver=$("$CLANG" --version | grep -m 1 -Eo 'clang version [0-9.]+')
kclangver="$(clang_version_from_file "$target")"

# ensure clang version matches that used to build the kernel
Expand Down Expand Up @@ -360,7 +367,7 @@ find_special_section_data() {
local SPECIAL_VARS
# If $AWK_OPTIONS are blank gawk would treat "" as a blank script
# shellcheck disable=SC2086
SPECIAL_VARS="$(readelf -wi "$VMLINUX" |
SPECIAL_VARS="$("$READELF" -wi "$VMLINUX" |
gawk --non-decimal-data $AWK_OPTIONS '
BEGIN { a = b = e = f = i = j = o = p = s = 0 }

Expand Down Expand Up @@ -698,8 +705,11 @@ fi

# Don't check external file.
# shellcheck disable=SC1090
[[ -f "$RELEASE_FILE" ]] && source "$RELEASE_FILE"
DISTRO="$ID"
if [[ -z "$USERSRCDIR" ]] && [[ -f "$RELEASE_FILE" ]]; then
source "$RELEASE_FILE"
DISTRO="$ID"
fi

if [[ "$DISTRO" = fedora ]] || [[ "$DISTRO" = rhel ]] || [[ "$DISTRO" = ol ]] || [[ "$DISTRO" = centos ]] || [[ "$DISTRO" = openEuler ]]; then
[[ -z "$VMLINUX" ]] && VMLINUX="/usr/lib/debug/lib/modules/$ARCHVERSION/vmlinux"
[[ -e "$VMLINUX" ]] || die "kernel-debuginfo-$ARCHVERSION not installed"
Expand Down Expand Up @@ -929,17 +939,17 @@ unset KPATCH_GCC_TEMPDIR
KPATCH_CC_PREFIX="$TOOLSDIR/kpatch-cc "
declare -a MAKEVARS
if [[ -n "$CONFIG_CC_IS_CLANG" ]]; then
MAKEVARS+=("CC=${KPATCH_CC_PREFIX}clang")
MAKEVARS+=("CC=${KPATCH_CC_PREFIX}${CLANG}")
MAKEVARS+=("HOSTCC=clang")
else
MAKEVARS+=("CC=${KPATCH_CC_PREFIX}gcc")
MAKEVARS+=("CC=${KPATCH_CC_PREFIX}${GCC}")
fi

if [[ -n "$CONFIG_LD_IS_LLD" ]]; then
MAKEVARS+=("LD=${KPATCH_CC_PREFIX}ld.lld")
MAKEVARS+=("LD=${KPATCH_CC_PREFIX}${LLD}")
MAKEVARS+=("HOSTLD=ld.lld")
else
MAKEVARS+=("LD=${KPATCH_CC_PREFIX}ld")
MAKEVARS+=("LD=${KPATCH_CC_PREFIX}${LD}")
fi


Expand Down Expand Up @@ -1072,7 +1082,7 @@ for i in $FILES; do
SYMVERS_FILE="$BUILDDIR/Module.symvers"
fi

readelf -s --wide "$KOBJFILE_PATH" > "$SYMTAB"
"$READELF" -s --wide "$KOBJFILE_PATH" > "$SYMTAB"
if [[ "$ARCH" = "ppc64le" ]]; then
sed -ri 's/\s+\[<localentry>: 8\]//' "$SYMTAB"
fi
Expand Down Expand Up @@ -1129,7 +1139,7 @@ fi
cd "$TEMPDIR/output" || die
# $KPATCH_LDFLAGS and result of find used as list, no quotes.
# shellcheck disable=SC2086,SC2046
ld -r $KPATCH_LDFLAGS -o ../patch/tmp_output.o $(find . -name "*.o") 2>&1 | logger || die
"$LD" -r $KPATCH_LDFLAGS -o ../patch/tmp_output.o $(find . -name "*.o") 2>&1 | logger || die

if [[ "$USE_KLP" -eq 1 ]]; then
cp -f "$TEMPDIR"/patch/tmp_output.o "$TEMPDIR"/patch/output.o || die
Expand All @@ -1138,7 +1148,7 @@ if [[ "$USE_KLP" -eq 1 ]]; then
else
# Add .kpatch.checksum for kpatch script
md5sum ../patch/tmp_output.o | awk '{printf "%s\0", $1}' > checksum.tmp || die
objcopy --add-section .kpatch.checksum=checksum.tmp --set-section-flags .kpatch.checksum=alloc,load,contents,readonly ../patch/tmp_output.o || die
"$OBJCOPY" --add-section .kpatch.checksum=checksum.tmp --set-section-flags .kpatch.checksum=alloc,load,contents,readonly ../patch/tmp_output.o || die
rm -f checksum.tmp
"$TOOLSDIR"/create-kpatch-module "$TEMPDIR"/patch/tmp_output.o "$TEMPDIR"/patch/output.o 2>&1 | logger 1
check_pipe_status create-kpatch-module
Expand All @@ -1154,7 +1164,8 @@ done

export KPATCH_BUILD="$KERNEL_SRCDIR" KPATCH_NAME="$MODNAME" \
KBUILD_EXTRA_SYMBOLS="$KBUILD_EXTRA_SYMBOLS" \
KPATCH_LDFLAGS="$KPATCH_LDFLAGS"
KPATCH_LDFLAGS="$KPATCH_LDFLAGS" \
CROSS_COMPILE="$CROSS_COMPILE"
save_env

make "${MAKEVARS[@]}" 2>&1 | logger || die
Expand Down Expand Up @@ -1192,7 +1203,7 @@ if [[ -n "$CONFIG_MODVERSIONS" ]]; then
fi
fi

readelf --wide --symbols "$TEMPDIR/patch/$MODNAME.ko" 2>/dev/null | \
"$READELF" --wide --symbols "$TEMPDIR/patch/$MODNAME.ko" 2>/dev/null | \
sed -r 's/\s+\[<localentry>: 8\]//' | \
awk '($4=="FUNC" || $4=="OBJECT") && ($5=="GLOBAL" || $5=="WEAK") && $7!="UND" {print $NF}' \
>"${TEMPDIR}"/new_symbols
Expand Down