[PATCH v5 bpf-next 2/9] bpf: Compile resolve_btfids tool at kernel compilation start

Jiri Olsa
2020-07-03T09:51:37Z

The resolve_btfids tool will be used during the vmlinux linking,
so it's necessary it's ready for it.

Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
Makefile | 22 ++++++++++++++++++----
tools/Makefile | 3 +++
tools/bpf/Makefile | 9 ++++++++-
3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index ae5d8220f431..8db4fd8097e0 100644
--- a/Makefile
+++ b/Makefile
@@ -1053,9 +1053,10 @@ export mod_sign_cmd

HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)

+has_libelf = $(call try-run,\
+ echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
+
ifdef CONFIG_STACK_VALIDATION
- has_libelf := $(call try-run,\
- echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
ifeq ($(has_libelf),1)
objtool_target := tools/objtool FORCE
else
@@ -1064,6 +1065,14 @@ ifdef CONFIG_STACK_VALIDATION
endif
endif

+ifdef CONFIG_DEBUG_INFO_BTF
+ ifeq ($(has_libelf),1)
+ resolve_btfids_target := tools/bpf/resolve_btfids FORCE
+ else
+ ERROR_RESOLVE_BTFIDS := 1
+ endif
+endif
+
PHONY += prepare0

export MODORDER := $(extmod-prefix)modules.order
@@ -1175,7 +1184,7 @@ prepare0: archprepare
$(Q)$(MAKE) $(build)=.

# All the preparing..
-prepare: prepare0 prepare-objtool
+prepare: prepare0 prepare-objtool prepare-resolve_btfids

# Support for using generic headers in asm-generic
asm-generic := -f $(srctree)/scripts/Makefile.asm-generic obj
@@ -1188,7 +1197,7 @@ uapi-asm-generic:
$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/uapi/asm \
generic=include/uapi/asm-generic

-PHONY += prepare-objtool
+PHONY += prepare-objtool prepare-resolve_btfids
prepare-objtool: $(objtool_target)
ifeq ($(SKIP_STACK_VALIDATION),1)
ifdef CONFIG_UNWINDER_ORC
@@ -1199,6 +1208,11 @@ else
endif
endif

+prepare-resolve_btfids: $(resolve_btfids_target)
+ifeq ($(ERROR_RESOLVE_BTFIDS),1)
+ @echo "error: Cannot resolve BTF IDs for CONFIG_DEBUG_INFO_BTF, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
+ @false
+endif
# Generate some files
# ---------------------------------------------------------------------------

diff --git a/tools/Makefile b/tools/Makefile
index bd778812e915..85af6ebbce91 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -67,6 +67,9 @@ cpupower: FORCE
cgroup firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging: FORCE
$(call descend,$@)

+bpf/%: FORCE
+ $(call descend,$@)
+
liblockdep: FORCE
$(call descend,lib/lockdep)

diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile
index 6df1850f8353..74bc9a105225 100644
--- a/tools/bpf/Makefile
+++ b/tools/bpf/Makefile
@@ -123,5 +123,12 @@ runqslower_install:
runqslower_clean:
$(call descend,runqslower,clean)

+resolve_btfids:
+ $(call descend,resolve_btfids)
+
+resolve_btfids_clean:
+ $(call descend,resolve_btfids,clean)
+
.PHONY: all install clean bpftool bpftool_install bpftool_clean \
- runqslower runqslower_install runqslower_clean
+ runqslower runqslower_install runqslower_clean \
+ resolve_btfids resolve_btfids_clean
--
2.25.4