linux/samples/bpf/Makefile
Yonghong Song 6bf3bbe1f4 samples/bpf: workaround clang asm goto compilation errors
x86 compilation has required asm goto support since 4.17.
Since clang does not support asm goto, at 4.17,
Commit b1ae32dbab ("x86/cpufeature: Guard asm_volatile_goto usage
for BPF compilation") worked around the issue by permitting an
alternative implementation without asm goto for clang.

At 5.0, more asm goto usages appeared.
  [yhs@148 x86]$ egrep -r asm_volatile_goto
  include/asm/cpufeature.h:     asm_volatile_goto("1: jmp 6f\n"
  include/asm/jump_label.h:     asm_volatile_goto("1:"
  include/asm/jump_label.h:     asm_volatile_goto("1:"
  include/asm/rmwcc.h:  asm_volatile_goto (fullop "; j" #cc " %l[cc_label]"     \
  include/asm/uaccess.h:        asm_volatile_goto("\n"                          \
  include/asm/uaccess.h:        asm_volatile_goto("\n"                          \
  [yhs@148 x86]$

Compiling samples/bpf directories, most bpf programs failed
compilation with error messages like:
  In file included from /home/yhs/work/bpf-next/samples/bpf/xdp_sample_pkts_kern.c:2:
  In file included from /home/yhs/work/bpf-next/include/linux/ptrace.h:6:
  In file included from /home/yhs/work/bpf-next/include/linux/sched.h:15:
  In file included from /home/yhs/work/bpf-next/include/linux/sem.h:5:
  In file included from /home/yhs/work/bpf-next/include/uapi/linux/sem.h:5:
  In file included from /home/yhs/work/bpf-next/include/linux/ipc.h:9:
  In file included from /home/yhs/work/bpf-next/include/linux/refcount.h:72:
  /home/yhs/work/bpf-next/arch/x86/include/asm/refcount.h:70:9: error: 'asm goto' constructs are not supported yet
        return GEN_BINARY_SUFFIXED_RMWcc(LOCK_PREFIX "subl",
               ^
  /home/yhs/work/bpf-next/arch/x86/include/asm/rmwcc.h:67:2: note: expanded from macro 'GEN_BINARY_SUFFIXED_RMWcc'
        __GEN_RMWcc(op " %[val], %[var]\n\t" suffix, var, cc,           \
        ^
  /home/yhs/work/bpf-next/arch/x86/include/asm/rmwcc.h:21:2: note: expanded from macro '__GEN_RMWcc'
        asm_volatile_goto (fullop "; j" #cc " %l[cc_label]"             \
        ^
  /home/yhs/work/bpf-next/include/linux/compiler_types.h:188:37: note: expanded from macro 'asm_volatile_goto'
  #define asm_volatile_goto(x...) asm goto(x)

Most implementation does not even provide an alternative
implementation. And it is also not practical to make changes
for each call site.

This patch workarounded the asm goto issue by redefining the macro like below:
  #define asm_volatile_goto(x...) asm volatile("invalid use of asm_volatile_goto")

If asm_volatile_goto is not used by bpf programs, which is typically the case, nothing bad
will happen. If asm_volatile_goto is used by bpf programs, which is incorrect, the compiler
will issue an error since "invalid use of asm_volatile_goto" is not valid assembly codes.

With this patch, all bpf programs under samples/bpf can pass compilation.

Note that bpf programs under tools/testing/selftests/bpf/ compiled fine as
they do not access kernel internal headers.

Fixes: e769742d35 ("Revert "x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs"")
Fixes: 18fe58229d ("x86, asm: change the GEN_*_RMWcc() macros to not quote the condition")
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-15 20:57:30 +01:00

287 lines
9.8 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
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_attach2
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 += load_sock_ops
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
# Libbpf dependencies
LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a
CGROUP_HELPERS := ../../tools/testing/selftests/bpf/cgroup_helpers.o
TRACE_HELPERS := ../../tools/testing/selftests/bpf/trace_helpers.o
fds_example-objs := bpf_load.o fds_example.o
sockex1-objs := bpf_load.o sockex1_user.o
sockex2-objs := bpf_load.o sockex2_user.o
sockex3-objs := bpf_load.o sockex3_user.o
tracex1-objs := bpf_load.o tracex1_user.o
tracex2-objs := bpf_load.o tracex2_user.o
tracex3-objs := bpf_load.o tracex3_user.o
tracex4-objs := bpf_load.o tracex4_user.o
tracex5-objs := bpf_load.o tracex5_user.o
tracex6-objs := bpf_load.o tracex6_user.o
tracex7-objs := bpf_load.o tracex7_user.o
load_sock_ops-objs := bpf_load.o load_sock_ops.o
test_probe_write_user-objs := bpf_load.o test_probe_write_user_user.o
trace_output-objs := bpf_load.o trace_output_user.o $(TRACE_HELPERS)
lathist-objs := bpf_load.o lathist_user.o
offwaketime-objs := bpf_load.o offwaketime_user.o $(TRACE_HELPERS)
spintest-objs := bpf_load.o spintest_user.o $(TRACE_HELPERS)
map_perf_test-objs := bpf_load.o map_perf_test_user.o
test_overhead-objs := bpf_load.o test_overhead_user.o
test_cgrp2_array_pin-objs := test_cgrp2_array_pin.o
test_cgrp2_attach-objs := test_cgrp2_attach.o
test_cgrp2_attach2-objs := test_cgrp2_attach2.o $(CGROUP_HELPERS)
test_cgrp2_sock-objs := test_cgrp2_sock.o
test_cgrp2_sock2-objs := bpf_load.o test_cgrp2_sock2.o
xdp1-objs := xdp1_user.o
# reuse xdp1 source intentionally
xdp2-objs := xdp1_user.o
xdp_router_ipv4-objs := bpf_load.o xdp_router_ipv4_user.o
test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
test_current_task_under_cgroup_user.o
trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
xdp_tx_iptunnel-objs := bpf_load.o xdp_tx_iptunnel_user.o
test_map_in_map-objs := bpf_load.o test_map_in_map_user.o
per_socket_stats_example-objs := cookie_uid_helper_example.o
xdp_redirect-objs := bpf_load.o xdp_redirect_user.o
xdp_redirect_map-objs := bpf_load.o xdp_redirect_map_user.o
xdp_redirect_cpu-objs := bpf_load.o xdp_redirect_cpu_user.o
xdp_monitor-objs := bpf_load.o xdp_monitor_user.o
xdp_rxq_info-objs := xdp_rxq_info_user.o
syscall_tp-objs := bpf_load.o syscall_tp_user.o
cpustat-objs := bpf_load.o cpustat_user.o
xdp_adjust_tail-objs := xdp_adjust_tail_user.o
xdpsock-objs := xdpsock_user.o
xdp_fwd-objs := xdp_fwd_user.o
task_fd_query-objs := bpf_load.o task_fd_query_user.o $(TRACE_HELPERS)
xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)
# Tell kbuild to always build the programs
always := $(hostprogs-y)
always += sockex1_kern.o
always += sockex2_kern.o
always += sockex3_kern.o
always += tracex1_kern.o
always += tracex2_kern.o
always += tracex3_kern.o
always += tracex4_kern.o
always += tracex5_kern.o
always += tracex6_kern.o
always += tracex7_kern.o
always += sock_flags_kern.o
always += test_probe_write_user_kern.o
always += trace_output_kern.o
always += tcbpf1_kern.o
always += tc_l2_redirect_kern.o
always += lathist_kern.o
always += offwaketime_kern.o
always += spintest_kern.o
always += map_perf_test_kern.o
always += test_overhead_tp_kern.o
always += test_overhead_raw_tp_kern.o
always += test_overhead_kprobe_kern.o
always += parse_varlen.o parse_simple.o parse_ldabs.o
always += test_cgrp2_tc_kern.o
always += xdp1_kern.o
always += xdp2_kern.o
always += xdp_router_ipv4_kern.o
always += test_current_task_under_cgroup_kern.o
always += trace_event_kern.o
always += sampleip_kern.o
always += lwt_len_hist_kern.o
always += xdp_tx_iptunnel_kern.o
always += test_map_in_map_kern.o
always += cookie_uid_helper_example.o
always += tcp_synrto_kern.o
always += tcp_rwnd_kern.o
always += tcp_bufs_kern.o
always += tcp_cong_kern.o
always += tcp_iw_kern.o
always += tcp_clamp_kern.o
always += tcp_basertt_kern.o
always += tcp_tos_reflect_kern.o
always += xdp_redirect_kern.o
always += xdp_redirect_map_kern.o
always += xdp_redirect_cpu_kern.o
always += xdp_monitor_kern.o
always += xdp_rxq_info_kern.o
always += xdp2skb_meta_kern.o
always += syscall_tp_kern.o
always += cpustat_kern.o
always += xdp_adjust_tail_kern.o
always += xdpsock_kern.o
always += xdp_fwd_kern.o
always += task_fd_query_kern.o
always += xdp_sample_pkts_kern.o
KBUILD_HOSTCFLAGS += -I$(objtree)/usr/include
KBUILD_HOSTCFLAGS += -I$(srctree)/tools/lib/
KBUILD_HOSTCFLAGS += -I$(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
HOSTCFLAGS_trace_helpers.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_trace_output_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_offwaketime_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_spintest_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_trace_event_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_sampleip_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_task_fd_query_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_xdp_sample_pkts_user.o += -I$(srctree)/tools/lib/bpf/
KBUILD_HOSTLDLIBS += $(LIBBPF) -lelf
HOSTLDLIBS_tracex4 += -lrt
HOSTLDLIBS_trace_output += -lrt
HOSTLDLIBS_map_perf_test += -lrt
HOSTLDLIBS_test_overhead += -lrt
HOSTLDLIBS_xdpsock += -pthread
# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
# make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
LLC ?= llc
CLANG ?= clang
LLVM_OBJCOPY ?= llvm-objcopy
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 $(ARCH)
endif
BTF_LLC_PROBE := $(shell $(LLC) -march=bpf -mattr=help 2>&1 | grep dwarfris)
BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF)
BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm')
BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \
$(CLANG) -target bpf -O2 -g -c -x c - -o ./llvm_btf_verify.o; \
readelf -S ./llvm_btf_verify.o | grep BTF; \
/bin/rm -f ./llvm_btf_verify.o)
ifneq ($(BTF_LLVM_PROBE),)
EXTRA_CFLAGS += -g
else
ifneq ($(and $(BTF_LLC_PROBE),$(BTF_PAHOLE_PROBE),$(BTF_OBJCOPY_PROBE)),)
EXTRA_CFLAGS += -g
LLC_FLAGS += -mattr=dwarfris
DWARF2BTF = y
endif
endif
# Trick to allow make to be run from this directory
all:
$(MAKE) -C ../../ $(CURDIR)/ BPF_SAMPLES_PATH=$(CURDIR)
clean:
$(MAKE) -C ../../ M=$(CURDIR) clean
@rm -f *~
$(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=
$(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE
$(call filechk,offsets,__SYSCALL_NRS_H__)
targets += syscall_nrs.s
clean-files += syscall_nrs.h
FORCE:
# Verify LLVM compiler tools are available and bpf target is supported by llc
.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC)
verify_cmds: $(CLANG) $(LLC)
@for TOOL in $^ ; do \
if ! (which -- "$${TOOL}" > /dev/null 2>&1); then \
echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\
exit 1; \
else true; fi; \
done
verify_target_bpf: verify_cmds
@if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \
echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\
echo " NOTICE: LLVM version >= 3.7.1 required" ;\
exit 2; \
else true; fi
$(BPF_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF)
$(src)/*.c: verify_target_bpf $(LIBBPF)
$(obj)/tracex5_kern.o: $(obj)/syscall_nrs.h
# 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.
$(obj)/%.o: $(src)/%.c
@echo " CLANG-bpf " $@
$(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) -I$(obj) \
-I$(srctree)/tools/testing/selftests/bpf/ \
-D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \
-D__TARGET_ARCH_$(ARCH) -Wno-compare-distinct-pointer-types \
-Wno-gnu-variable-sized-type-not-at-end \
-Wno-address-of-packed-member -Wno-tautological-compare \
-Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \
-I$(srctree)/samples/bpf/ -include asm_goto_workaround.h \
-O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@
ifeq ($(DWARF2BTF),y)
$(BTF_PAHOLE) -J $@
endif