On Mon, Aug 19, 2024 at 06:03:05PM +0200, Vegard Nossum wrote:
> Make link-vmlinux.sh print the commands it wants to run instead of
> actually running them when $dry_run is defined.
Do we need link-vmlinux.sh to show it's commands? Couldn't we just show
the call of link-vmlinux.sh instead (and replace/hide the '+' prefix if
'dry_run' is set)? Why not? (I guess, you found good reasons. Can you
please add them to the commit message?)
>
> This is needed in order for make -n/--dry-run to output a complete
> build script.
>
> Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
> ---
> scripts/Makefile.vmlinux | 15 ++++++++++++--
> scripts/link-vmlinux.sh | 44 ++++++++++++++++++++++++++--------------
> 2 files changed, 42 insertions(+), 17 deletions(-)
>
> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> index 10d80e07f945c..1fe0faab52889 100644
> --- a/scripts/Makefile.vmlinux
> +++ b/scripts/Makefile.vmlinux
> @@ -1,5 +1,12 @@
> # SPDX-License-Identifier: GPL-2.0-only
>
> +# there doesn't seem to be a straightforward way for 'make -n' to output
> +# one command while actually executing another, so we resort to this hack
> +# where we set an environment variable differently depending on whether
> +# we are executing from 'make' or executing from the 'make -n' log.
> +LINK_VMLINUX=scripts/link-vmlinux.sh
> +export LINK_VMLINUX
> +
> PHONY := __default
> __default: vmlinux
>
> @@ -29,7 +36,8 @@ ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
>
> # Final link of vmlinux with optional arch pass after final link
> cmd_link_vmlinux = \
> - $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)"; \
> + "$${LINK_VMLINUX}" \
> + "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)"; \
> $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
>
> # We don't know how to build these
> @@ -37,7 +45,10 @@ PHONY += vmlinux.o
> PHONY += $(KBUILD_LDS)
>
> targets += vmlinux
> -vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
> +vmlinux: $(LINK_VMLINUX) vmlinux.o $(KBUILD_LDS) FORCE
> +ifdef dry_run
> + @LINK_VMLINUX=/bin/true
> +endif
> +$(call if_changed_dep,link_vmlinux)
>
> # Add FORCE to the prequisites of a target to force it to be always rebuilt.
> diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
> index f7b2503cdba95..fd32e48a8a455 100755
> --- a/scripts/link-vmlinux.sh
> +++ b/scripts/link-vmlinux.sh
> @@ -32,6 +32,17 @@ LD="$1"
> KBUILD_LDFLAGS="$2"
> LDFLAGS_vmlinux="$3"
>
> +# If $dry_run is set, just echo the command instead of executing it.
> +run()
> +{
> + if [ ! -v dry_run ]
> + then
> + eval "$1"
> + else
> + echo "$1"
> + fi
> +}
> +
> is_enabled() {
> grep -q "^$1=y" include/config/auto.conf
> }
> @@ -40,7 +51,10 @@ is_enabled() {
> # Will be supressed by "make -s"
> info()
> {
> - printf " %-7s %s\n" "${1}" "${2}"
> + if [ ! -v dry_run ]
> + then
> + printf " %-7s %s\n" "${1}" "${2}"
> + fi
> }
>
> # Link of vmlinux
Do you have some thoughts about the
if is_enabled ...
lines? Do we need to defer the evaluation of include/config/auto.conf,
too?
> @@ -97,10 +111,10 @@ vmlinux_link()
> ldflags="${ldflags} ${wl}-Map=${output}.map"
> fi
>
> - ${ld} ${ldflags} -o ${output} \
> + run "${ld} ${ldflags} -o ${output} \
> ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \
> ${wl}--start-group ${libs} ${wl}--end-group \
> - ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs}
> + ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs}"
> }
>
> # generate .BTF typeinfo from DWARF debuginfo
> @@ -129,8 +143,8 @@ gen_btf()
> # deletes all symbols including __start_BTF and __stop_BTF, which will
> # be redefined in the linker script. Add 2>/dev/null to suppress GNU
> # objcopy warnings: "empty loadable segment detected at ..."
> - ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
> - --strip-all ${1} "${btf_data}" 2>/dev/null
> + run "${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
> + --strip-all ${1} "${btf_data}" 2>/dev/null"
^^^^^^^^^^^^^
Backslashes to keep ${btf_data} quoted are missing.
> # Change e_type to ET_REL so that it can be used to link final vmlinux.
> # GNU ld 2.35+ and lld do not allow an ET_EXEC input.
> if is_enabled CONFIG_CPU_BIG_ENDIAN; then
printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none
'dd' should probably be called via 'run'.
> @@ -161,11 +175,11 @@ kallsyms()
> fi
>
> info KSYMS "${2}.S"
> - scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S"
> + run "scripts/kallsyms ${kallsymopt} \"${1}\" > \"${2}.S\""
>
> info AS "${2}.o"
> - ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
> - ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S"
> + run "${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
> + ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o \"${2}.o\" \"${2}.S\""
>
> kallsymso=${2}.o
> }
> @@ -184,12 +198,12 @@ sysmap_and_kallsyms()
> mksysmap()
> {
> info NM ${2}
> - ${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}"
> + run "${NM} -n \"${1}\" | sed -f \"${srctree}/scripts/mksysmap\" > \"${2}\""
> }
>
> sorttable()
> {
> - ${objtree}/scripts/sorttable ${1}
> + run "${objtree}/scripts/sorttable ${1}"
> }
>
> cleanup()
I know, 'link-vmlinux.sh clean' will not by called by 'make --dry-run
clean' (as there is no '+' prefix in the call in Makefile), but for
consistency, I'd like to see also cleanup() be prepared for handling
dry_run correctly.
Can you please move patch 11 (resetting of KBUILD_VERBOSE if '--dry-run'
or '--silent' is given) before this one?
Does '${MAKE} ...' also need to be called via 'run'?
> @@ -270,13 +284,13 @@ if is_enabled CONFIG_KALLSYMS; then
> strip_debug=1
>
> sysmap_and_kallsyms .tmp_vmlinux1
> - size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
> + [ -v dry_run ] || size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
>
> vmlinux_link .tmp_vmlinux2
> sysmap_and_kallsyms .tmp_vmlinux2
> - size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
> + [ -v dry_run ] || size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
>
> - if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
> + if [ ! -v dry_run ] || [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
> vmlinux_link .tmp_vmlinux3
> sysmap_and_kallsyms .tmp_vmlinux3
> fi
> @@ -289,7 +303,7 @@ vmlinux_link vmlinux
> # fill in BTF IDs
> if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then
> info BTFIDS vmlinux
> - ${RESOLVE_BTFIDS} vmlinux
> + run ${RESOLVE_BTFIDS} vmlinux
Quotes are missing, as run only evaluated its first argument.
> fi
>
> mksysmap vmlinux System.map
> @@ -303,7 +317,7 @@ if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
I am sceptical about
if ! sorttable vmlinux
and similar. With dry_run being set, sorttable shows the call of
'sorttable' and always returns success. In effect, the resulting output
shell build script will miss such error detection.
I think it would be really good, if we could skip patching
link-vmlinux.sh but show its call instead.
Kind regards,
Nicolas
> fi
>
> # step a (see comment above)
> -if is_enabled CONFIG_KALLSYMS; then
> +if [ ! -v dry_run ] && is_enabled CONFIG_KALLSYMS; then
> if ! cmp -s System.map "${kallsyms_sysmap}"; then
> echo >&2 Inconsistent kallsyms data
> echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
> --
> 2.34.1
>
--
Nicolas
