From db16c1fe92d7ba7d39061faef897842baee2c887 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Tue, 13 Apr 2021 21:00:43 +0200 Subject: bpf: Generate BTF_KIND_FLOAT when linking vmlinux pahole v1.21 supports the --btf_gen_floats flag, which makes it generate the information about the floating-point types [1]. Adjust link-vmlinux.sh to pass this flag to pahole in case it's supported, which is determined using a simple version check. [1] https://lore.kernel.org/dwarves/YHRiXNX1JUF2Az0A@kernel.org/ Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210413190043.21918-1-iii@linux.ibm.com --- scripts/link-vmlinux.sh | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'scripts/link-vmlinux.sh') diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 3b261b0f74f0..667aacb9261c 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -213,6 +213,7 @@ vmlinux_link() gen_btf() { local pahole_ver + local extra_paholeopt= if ! [ -x "$(command -v ${PAHOLE})" ]; then echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" @@ -227,8 +228,12 @@ gen_btf() vmlinux_link ${1} + if [ "${pahole_ver}" -ge "121" ]; then + extra_paholeopt="${extra_paholeopt} --btf_gen_floats" + fi + info "BTF" ${2} - LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} + LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${extra_paholeopt} ${1} # Create ${2} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all -- cgit v1.2.3 From 5cc1247204616528b427e276c97c5bc4c9612347 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 5 Mar 2021 10:27:07 +0100 Subject: kbuild: add CONFIG_VMLINUX_MAP expert option It can be quite useful to have ld emit a link map file, in order to debug or verify that special sections end up where they are supposed to, and to see what LD_DEAD_CODE_DATA_ELIMINATION manages to get rid of. The only reason I'm not just adding this unconditionally is that the .map file can be rather large (several MB), and that's a waste of space when one isn't interested in these things. Also make it depend on CONFIG_EXPERT. Signed-off-by: Rasmus Villemoes Signed-off-by: Masahiro Yamada --- scripts/link-vmlinux.sh | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'scripts/link-vmlinux.sh') diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 3b261b0f74f0..855fd4e6f03e 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -155,6 +155,7 @@ vmlinux_link() local output=${1} local objects local strip_debug + local map_option info LD ${output} @@ -166,6 +167,10 @@ vmlinux_link() strip_debug=-Wl,--strip-debug fi + if [ -n "${CONFIG_VMLINUX_MAP}" ]; then + map_option="-Map=${output}.map" + fi + if [ "${SRCARCH}" != "um" ]; then if [ -n "${CONFIG_LTO_CLANG}" ]; then # Use vmlinux.o instead of performing the slow LTO @@ -187,6 +192,7 @@ vmlinux_link() ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \ ${strip_debug#-Wl,} \ -o ${output} \ + ${map_option} \ -T ${lds} ${objects} else objects="-Wl,--whole-archive \ @@ -200,6 +206,7 @@ vmlinux_link() ${CC} ${CFLAGS_vmlinux} \ ${strip_debug} \ -o ${output} \ + ${map_option:+-Wl,${map_option}} \ -Wl,-T,${lds} \ ${objects} \ -lutil -lrt -lpthread @@ -303,6 +310,7 @@ cleanup() rm -f .tmp_vmlinux* rm -f System.map rm -f vmlinux + rm -f vmlinux.map rm -f vmlinux.o } -- cgit v1.2.3 From 0b956e204132ce3fe4221a062638bf83a30e6200 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 5 Mar 2021 11:02:12 +0100 Subject: kbuild: apply fixdep logic to link-vmlinux.sh The patch adding CONFIG_VMLINUX_MAP revealed a small defect in the build system: link-vmlinux.sh takes decisions based on CONFIG_* options, but changing one of those does not always lead to vmlinux being linked again. For most of the CONFIG_* knobs referenced previously, this has probably been hidden by those knobs also affecting some object file, hence indirectly also vmlinux. But CONFIG_VMLINUX_MAP is only handled inside link-vmlinux.sh, and changing CONFIG_VMLINUX_MAP=n to CONFIG_VMLINUX_MAP=y does not cause the build system to re-link (and hence have vmlinux.map emitted). Since that map file is mostly a debugging aid, this is merely a nuisance which is easily worked around by just deleting vmlinux and building again. But one could imagine other (possibly future) CONFIG options that actually do affect the vmlinux binary but which are not captured through some object file dependency. To fix this, make link-vmlinux.sh emit a .vmlinux.d file in the same format as the dependency files generated by gcc, and apply the fixdep logic to that. I've tested that this correctly works with both in-tree and out-of-tree builds. Signed-off-by: Rasmus Villemoes Signed-off-by: Masahiro Yamada --- scripts/link-vmlinux.sh | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'scripts/link-vmlinux.sh') diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 855fd4e6f03e..e9516bdfcc6f 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -312,6 +312,7 @@ cleanup() rm -f vmlinux rm -f vmlinux.map rm -f vmlinux.o + rm -f .vmlinux.d } on_exit() @@ -449,3 +450,6 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then exit 1 fi fi + +# For fixdep +echo "vmlinux: $0" > .vmlinux.d -- cgit v1.2.3 From 51eb95e2da41802454f48b9afeb4d96a77295035 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 4 May 2021 20:35:27 -0700 Subject: kbuild: Don't remove link-vmlinux temporary files on exit/signal Keep them around until they are cleaned up by make clean. This uses a bit more disk space, but makes it easier to debug any problems with the kernel link process. Suggested-by: Masahiro Yamada Signed-off-by: Andi Kleen Signed-off-by: Masahiro Yamada --- scripts/link-vmlinux.sh | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'scripts/link-vmlinux.sh') diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 7d112681f332..f4de4c97015b 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -320,20 +320,6 @@ cleanup() rm -f .vmlinux.d } -on_exit() -{ - if [ $? -ne 0 ]; then - cleanup - fi -} -trap on_exit EXIT - -on_signals() -{ - exit 1 -} -trap on_signals HUP INT QUIT TERM - # Use "make V=1" to debug this script case "${KBUILD_VERBOSE}" in *1*) -- cgit v1.2.3 From ff2e6efda0d5c51b33e2bcc0b0b981ac0a0ef214 Mon Sep 17 00:00:00 2001 From: Javier Martinez Canillas Date: Wed, 26 May 2021 23:52:28 +0200 Subject: kbuild: Quote OBJCOPY var to avoid a pahole call break the build The ccache tool can be used to speed up cross-compilation, by calling the compiler and binutils through ccache. For example, following should work: $ export ARCH=arm64 CROSS_COMPILE="ccache aarch64-linux-gnu-" $ make M=drivers/gpu/drm/rockchip/ but pahole fails to extract the BTF info from DWARF, breaking the build: CC [M] drivers/gpu/drm/rockchip//rockchipdrm.mod.o LD [M] drivers/gpu/drm/rockchip//rockchipdrm.ko BTF [M] drivers/gpu/drm/rockchip//rockchipdrm.ko aarch64-linux-gnu-objcopy: invalid option -- 'J' Usage: aarch64-linux-gnu-objcopy [option(s)] in-file [out-file] Copies a binary file, possibly transforming it in the process ... make[1]: *** [scripts/Makefile.modpost:156: __modpost] Error 2 make: *** [Makefile:1866: modules] Error 2 this fails because OBJCOPY is set to "ccache aarch64-linux-gnu-copy" and later pahole is executed with the following command line: LLVM_OBJCOPY=$(OBJCOPY) $(PAHOLE) -J --btf_base vmlinux $@ which gets expanded to: LLVM_OBJCOPY=ccache aarch64-linux-gnu-objcopy pahole -J ... instead of: LLVM_OBJCOPY="ccache aarch64-linux-gnu-objcopy" pahole -J ... Fixes: 5f9ae91f7c0d ("kbuild: Build kernel module BTFs if BTF is enabled and pahole supports it") Signed-off-by: Javier Martinez Canillas Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Acked-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/bpf/20210526215228.3729875-1-javierm@redhat.com --- scripts/link-vmlinux.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts/link-vmlinux.sh') diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index f4de4c97015b..0e0f6466b18d 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -240,7 +240,7 @@ gen_btf() fi info "BTF" ${2} - LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${extra_paholeopt} ${1} + LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${extra_paholeopt} ${1} # Create ${2} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all -- cgit v1.2.3