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selftests/bpf: Allow building with extra flags

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In order to specify extra compilation or linking flags to BPF selftests,
it is possible to set EXTRA_CFLAGS and EXTRA_LDFLAGS from the command
line. The problem is that they are not propagated to sub-make calls
(runqslower, bpftool, libbpf) and in the better case are not applied, in
the worse case cause the entire build fail.

Propagate EXTRA_CFLAGS and EXTRA_LDFLAGS to the sub-makes.

This, for instance, allows to build selftests as PIE with

    $ make EXTRA_CFLAGS='-fPIE' EXTRA_LDFLAGS='-pie'

Without this change, the command would fail because libbpf.a would not
be built with -fPIE and other PIE binaries would not link against it.

The only problem is that we have to explicitly provide empty
EXTRA_CFLAGS='' and EXTRA_LDFLAGS='' to the builds of kernel modules as
we don't want to build modules with flags used for userspace (the above
example would fail as kernel doesn't support PIE).

Signed-off-by: Viktor Malik <vmalik@redhat.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This commit is contained in:
Viktor Malik 2024-11-01 09:27:11 +01:00 committed by Andrii Nakryiko
parent 5f67329cb2
commit ec8d3b5c2a
1 changed files with 23 additions and 11 deletions
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34
tools/testing/selftests/bpf/Makefile
View File

@ -297,25 +297,33 @@ $(OUTPUT)/sign-file: ../../../../scripts/sign-file.c
$(OUTPUT)/bpf_testmod.ko: $(VMLINUX_BTF) $(RESOLVE_BTFIDS) $(wildcard bpf_testmod/Makefile bpf_testmod/*.[ch])
$(call msg,MOD,,$@)
$(Q)$(RM) bpf_testmod/bpf_testmod.ko # force re-compilation
$(Q)$(MAKE) $(submake_extras) RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) -C bpf_testmod
$(Q)$(MAKE) $(submake_extras) -C bpf_testmod \
RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) \
EXTRA_CFLAGS='' EXTRA_LDFLAGS=''
$(Q)cp bpf_testmod/bpf_testmod.ko $@
$(OUTPUT)/bpf_test_no_cfi.ko: $(VMLINUX_BTF) $(RESOLVE_BTFIDS) $(wildcard bpf_test_no_cfi/Makefile bpf_test_no_cfi/*.[ch])
$(call msg,MOD,,$@)
$(Q)$(RM) bpf_test_no_cfi/bpf_test_no_cfi.ko # force re-compilation
$(Q)$(MAKE) $(submake_extras) RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) -C bpf_test_no_cfi
$(Q)$(MAKE) $(submake_extras) -C bpf_test_no_cfi \
RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) \
EXTRA_CFLAGS='' EXTRA_LDFLAGS=''
$(Q)cp bpf_test_no_cfi/bpf_test_no_cfi.ko $@
$(OUTPUT)/bpf_test_modorder_x.ko: $(VMLINUX_BTF) $(RESOLVE_BTFIDS) $(wildcard bpf_test_modorder_x/Makefile bpf_test_modorder_x/*.[ch])
$(call msg,MOD,,$@)
$(Q)$(RM) bpf_test_modorder_x/bpf_test_modorder_x.ko # force re-compilation
$(Q)$(MAKE) $(submake_extras) RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) -C bpf_test_modorder_x
$(Q)$(MAKE) $(submake_extras) -C bpf_test_modorder_x \
RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) \
EXTRA_CFLAGS='' EXTRA_LDFLAGS=''
$(Q)cp bpf_test_modorder_x/bpf_test_modorder_x.ko $@
$(OUTPUT)/bpf_test_modorder_y.ko: $(VMLINUX_BTF) $(RESOLVE_BTFIDS) $(wildcard bpf_test_modorder_y/Makefile bpf_test_modorder_y/*.[ch])
$(call msg,MOD,,$@)
$(Q)$(RM) bpf_test_modorder_y/bpf_test_modorder_y.ko # force re-compilation
$(Q)$(MAKE) $(submake_extras) RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) -C bpf_test_modorder_y
$(Q)$(MAKE) $(submake_extras) -C bpf_test_modorder_y \
RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) \
EXTRA_CFLAGS='' EXTRA_LDFLAGS=''
$(Q)cp bpf_test_modorder_y/bpf_test_modorder_y.ko $@
@ -335,8 +343,8 @@ $(OUTPUT)/runqslower: $(BPFOBJ) | $(DEFAULT_BPFTOOL) $(RUNQSLOWER_OUTPUT)
BPFTOOL_OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \
BPFOBJ_OUTPUT=$(BUILD_DIR)/libbpf/ \
BPFOBJ=$(BPFOBJ) BPF_INCLUDE=$(INCLUDE_DIR) \
EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS)' \
EXTRA_LDFLAGS='$(SAN_LDFLAGS)' && \
EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS) $(EXTRA_CFLAGS)' \
EXTRA_LDFLAGS='$(SAN_LDFLAGS) $(EXTRA_LDFLAGS)' && \
cp $(RUNQSLOWER_OUTPUT)runqslower $@
TEST_GEN_PROGS_EXTENDED += $(TRUNNER_BPFTOOL)
@ -369,7 +377,8 @@ $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \
$(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool
$(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \
ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD="$(HOSTLD)" \
EXTRA_CFLAGS='-g $(OPT_FLAGS)' \
EXTRA_CFLAGS='-g $(OPT_FLAGS) $(EXTRA_CFLAGS)' \
EXTRA_LDFLAGS='$(EXTRA_LDFLAGS)' \
OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \
LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
LIBBPF_DESTDIR=$(HOST_SCRATCH_DIR)/ \
@ -380,7 +389,8 @@ $(CROSS_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \
$(BPFOBJ) | $(BUILD_DIR)/bpftool
$(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \
ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) \
EXTRA_CFLAGS='-g $(OPT_FLAGS)' \
EXTRA_CFLAGS='-g $(OPT_FLAGS) $(EXTRA_CFLAGS)' \
EXTRA_LDFLAGS='$(EXTRA_LDFLAGS)' \
OUTPUT=$(BUILD_DIR)/bpftool/ \
LIBBPF_OUTPUT=$(BUILD_DIR)/libbpf/ \
LIBBPF_DESTDIR=$(SCRATCH_DIR)/ \
@ -403,8 +413,8 @@ $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
$(APIDIR)/linux/bpf.h \
| $(BUILD_DIR)/libbpf
$(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(BUILD_DIR)/libbpf/ \
EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS)' \
EXTRA_LDFLAGS='$(SAN_LDFLAGS)' \
EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS) $(EXTRA_CFLAGS)' \
EXTRA_LDFLAGS='$(SAN_LDFLAGS) $(EXTRA_LDFLAGS)' \
DESTDIR=$(SCRATCH_DIR) prefix= all install_headers
ifneq ($(BPFOBJ),$(HOST_BPFOBJ))
@ -412,7 +422,9 @@ $(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
$(APIDIR)/linux/bpf.h \
| $(HOST_BUILD_DIR)/libbpf
$(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) \
EXTRA_CFLAGS='-g $(OPT_FLAGS)' ARCH= CROSS_COMPILE= \
ARCH= CROSS_COMPILE= \
EXTRA_CFLAGS='-g $(OPT_FLAGS) $(EXTRA_CFLAGS)' \
EXTRA_LDFLAGS='$(EXTRA_LDFLAGS)' \
OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
CC="$(HOSTCC)" LD="$(HOSTLD)" \
DESTDIR=$(HOST_SCRATCH_DIR)/ prefix= all install_headers