[PATCH bpf-next 8/8] samples: bpf: Makefile: base progs build on Makefile.progs

[Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>]

The main reason for that - HOSTCC and CC have different aims.
It was tested for arm cross compilation, based on linaro toolchain,
but should work for others.

In order to split cross compilation with host build, base bpf samples
on Makefile.progs. It's also convenient when NFC is used:

export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabihf-
make samples/bpf/ SYSROOT="path/to/sysroot"

Sysroot contains correct headers installed ofc.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 samples/bpf/Makefile   | 164 ++++++++++++++++++++++++-----------------
 samples/bpf/README.rst |   7 ++
 2 files changed, 102 insertions(+), 69 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 043f9cc14cdd..ed7131851172 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -4,55 +4,53 @@ BPF_SAMPLES_PATH ?= $(abspath $(srctree)/$(src))
 TOOLS_PATH := $(BPF_SAMPLES_PATH)/../../tools
 
 # List of programs to build
-hostprogs-y := test_lru_dist
-hostprogs-y += sock_example
-hostprogs-y += fds_example
-hostprogs-y += sockex1
-hostprogs-y += sockex2
-hostprogs-y += sockex3
-hostprogs-y += tracex1
-hostprogs-y += tracex2
-hostprogs-y += tracex3
-hostprogs-y += tracex4
-hostprogs-y += tracex5
-hostprogs-y += tracex6
-hostprogs-y += tracex7
-hostprogs-y += test_probe_write_user
-hostprogs-y += trace_output
-hostprogs-y += lathist
-hostprogs-y += offwaketime
-hostprogs-y += spintest
-hostprogs-y += map_perf_test
-hostprogs-y += test_overhead
-hostprogs-y += test_cgrp2_array_pin
-hostprogs-y += test_cgrp2_attach
-hostprogs-y += test_cgrp2_sock
-hostprogs-y += test_cgrp2_sock2
-hostprogs-y += xdp1
-hostprogs-y += xdp2
-hostprogs-y += xdp_router_ipv4
-hostprogs-y += test_current_task_under_cgroup
-hostprogs-y += trace_event
-hostprogs-y += sampleip
-hostprogs-y += tc_l2_redirect
-hostprogs-y += lwt_len_hist
-hostprogs-y += xdp_tx_iptunnel
-hostprogs-y += test_map_in_map
-hostprogs-y += per_socket_stats_example
-hostprogs-y += xdp_redirect
-hostprogs-y += xdp_redirect_map
-hostprogs-y += xdp_redirect_cpu
-hostprogs-y += xdp_monitor
-hostprogs-y += xdp_rxq_info
-hostprogs-y += syscall_tp
-hostprogs-y += cpustat
-hostprogs-y += xdp_adjust_tail
-hostprogs-y += xdpsock
-hostprogs-y += xdp_fwd
-hostprogs-y += task_fd_query
-hostprogs-y += xdp_sample_pkts
-hostprogs-y += ibumad
-hostprogs-y += hbm
+progs-y := test_lru_dist
+progs-y += sock_example
+progs-y += fds_example
+progs-y += sockex1
+progs-y += sockex2
+progs-y += sockex3
+progs-y += tracex1
+progs-y += tracex2
+progs-y += tracex3
+progs-y += tracex4
+progs-y += tracex5
+progs-y += tracex6
+progs-y += tracex7
+progs-y += test_probe_write_user
+progs-y += trace_output
+progs-y += lathist
+progs-y += offwaketime
+progs-y += spintest
+progs-y += map_perf_test
+progs-y += test_overhead
+progs-y += test_cgrp2_array_pin
+progs-y += test_cgrp2_attach
+progs-y += test_cgrp2_sock
+progs-y += test_cgrp2_sock2
+progs-y += xdp1
+progs-y += xdp2
+progs-y += xdp_router_ipv4
+progs-y += test_current_task_under_cgroup
+progs-y += trace_event
+progs-y += sampleip
+progs-y += tc_l2_redirect
+progs-y += lwt_len_hist
+progs-y += xdp_tx_iptunnel
+progs-y += test_map_in_map
+progs-y += xdp_redirect_map
+progs-y += xdp_redirect_cpu
+progs-y += xdp_monitor
+progs-y += xdp_rxq_info
+progs-y += syscall_tp
+progs-y += cpustat
+progs-y += xdp_adjust_tail
+progs-y += xdpsock
+progs-y += xdp_fwd
+progs-y += task_fd_query
+progs-y += xdp_sample_pkts
+progs-y += ibumad
+progs-y += hbm
 
 # Libbpf dependencies
 LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a
@@ -111,7 +109,7 @@ ibumad-objs := bpf_load.o ibumad_user.o $(TRACE_HELPERS)
 hbm-objs := bpf_load.o hbm.o $(CGROUP_HELPERS)
 
 # Tell kbuild to always build the programs
-always := $(hostprogs-y)
+always := $(progs-y)
 always += sockex1_kern.o
 always += sockex2_kern.o
 always += sockex3_kern.o
@@ -171,26 +169,51 @@ always += ibumad_kern.o
 always += hbm_out_kern.o
 always += hbm_edt_kern.o
 
-KBUILD_HOSTCFLAGS += -I$(objtree)/usr/include
-KBUILD_HOSTCFLAGS += -I$(srctree)/tools/lib/bpf/
-KBUILD_HOSTCFLAGS += -I$(srctree)/tools/testing/selftests/bpf/
-KBUILD_HOSTCFLAGS += -I$(srctree)/tools/lib/ -I$(srctree)/tools/include
-KBUILD_HOSTCFLAGS += -I$(srctree)/tools/perf
-
-HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable
-
-KBUILD_HOSTLDLIBS		+= $(LIBBPF) -lelf
-HOSTLDLIBS_tracex4		+= -lrt
-HOSTLDLIBS_trace_output	+= -lrt
-HOSTLDLIBS_map_perf_test	+= -lrt
-HOSTLDLIBS_test_overhead	+= -lrt
-HOSTLDLIBS_xdpsock		+= -pthread
-
 # Strip all expet -D options needed to handle linux headers
 # for arm it's __LINUX_ARM_ARCH__ and potentially others fork vars
 D_OPTIONS = $(shell echo "$(KBUILD_CFLAGS) " | sed 's/[[:blank:]]/\n/g' | \
 	sed '/^-D/!d' | tr '\n' ' ')
 
+ifdef SYSROOT
+ccflags-y += --sysroot=${SYSROOT}
+ccflags-y += -I${SYSROOT}/usr/include
+CLANG_EXTRA_CFLAGS := $(ccflags-y)
+PROGS_LDFLAGS := -L${SYSROOT}/usr/lib
+endif
+
+ccflags-y += -I$(srctree)/tools/lib/bpf/
+ccflags-y += -I$(srctree)/tools/testing/selftests/bpf/
+ccflags-y += -I$(srctree)/tools/lib/
+ccflags-y += -I$(srctree)/tools/perf
+
+ccflags-y += $(D_OPTIONS)
+ccflags-y += -Wall
+ccflags-y += -Wmissing-prototypes
+ccflags-y += -Wstrict-prototypes
+ccflags-y += -fomit-frame-pointer
+
+PROGS_CFLAGS := $(ccflags-y)
+
+ccflags-y += -I$(objtree)/usr/include
+ccflags-y += -I$(srctree)/tools/include
+
+PROGCFLAGS_bpf_load.o += -I$(objtree)/usr/include -I$(srctree)/tools/include \
+			 -Wno-unused-variable
+PROGCFLAGS_sampleip_user.o += -I$(srctree)/tools/include
+PROGCFLAGS_task_fd_query_user.o += -I$(srctree)/tools/include
+PROGCFLAGS_trace_event_user.o += -I$(srctree)/tools/include
+PROGCFLAGS_trace_output_user.o += -I$(srctree)/tools/include
+PROGCFLAGS_tracex6_user.o += -I$(srctree)/tools/include
+PROGCFLAGS_xdp_sample_pkts_user.o += -I$(srctree)/tools/include
+PROGCFLAGS_xdpsock_user.o += -I$(srctree)/tools/include
+
+PROGS_LDLIBS			:= $(LIBBPF) -lelf
+PROGLDLIBS_tracex4		+= -lrt
+PROGLDLIBS_trace_output		+= -lrt
+PROGLDLIBS_map_perf_test	+= -lrt
+PROGLDLIBS_test_overhead	+= -lrt
+PROGLDLIBS_xdpsock		+= -pthread
+
 CLANG_EXTRA_CFLAGS += $(D_OPTIONS)
 
 # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
@@ -202,15 +225,14 @@ BTF_PAHOLE ?= pahole
 
 # Detect that we're cross compiling and use the cross compiler
 ifdef CROSS_COMPILE
-HOSTCC = $(CROSS_COMPILE)gcc
 CLANG_ARCH_ARGS = --target=$(notdir $(CROSS_COMPILE:%-=%))
 endif
 
 # Don't evaluate probes and warnings if we need to run make recursively
 ifneq ($(src),)
 HDR_PROBE := $(shell printf "\#include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \
-	$(HOSTCC) $(KBUILD_HOSTCFLAGS) -x c - -o /dev/null 2>/dev/null && \
-	echo okay)
+	$(CC) $(PROGS_CFLAGS) $(PROGS_LDFLAGS) -x c - -o /dev/null \
+	2>/dev/null && echo okay)
 
 ifeq ($(HDR_PROBE),)
 $(warning WARNING: Detected possible issues with include path.)
@@ -246,7 +268,9 @@ clean:
 
 $(LIBBPF): FORCE
 # Fix up variables inherited from Kbuild that tools/ build system won't like
-	$(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(BPF_SAMPLES_PATH)/../../ O=
+	$(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(ccflags-y)" \
+		EXTRA_CXXFLAGS="$(ccflags-y)" LDFLAGS=$(PROGS_LDFLAGS) \
+		srctree=$(BPF_SAMPLES_PATH)/../../ O=
 
 $(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
 	$(call filechk,offsets,__SYSCALL_NRS_H__)
@@ -283,6 +307,8 @@ $(obj)/hbm_out_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
 $(obj)/hbm.o: $(src)/hbm.h
 $(obj)/hbm_edt_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
 
+-include $(BPF_SAMPLES_PATH)/Makefile.prog
+
 # asm/sysreg.h - inline assembly used by it is incompatible with llvm.
 # But, there is no easy way to fix it, so just exclude it since it is
 # useless for BPF samples.
diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
index 5f27e4faca50..6b5e4eace977 100644
--- a/samples/bpf/README.rst
+++ b/samples/bpf/README.rst
@@ -74,3 +74,10 @@ samples for the cross target.
 export ARCH=arm64
 export CROSS_COMPILE="aarch64-linux-gnu-"
 make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
+
+If need to use environment of target board, the SYSROOT also can be set,
+pointing on FS of target board:
+
+make samples/bpf/ LLC=~/git/llvm/build/bin/llc \
+     CLANG=~/git/llvm/build/bin/clang \
+     SYSROOT=~/some_sdk/linux-devkit/sysroots/aarch64-linux-gnu
-- 
2.17.1