v4.19.13 snapshot.
diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile
new file mode 100644
index 0000000..53b60ad
--- /dev/null
+++ b/tools/bpf/Makefile
@@ -0,0 +1,107 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../scripts/Makefile.include
+
+prefix ?= /usr/local
+
+CC = gcc
+LEX = flex
+YACC = bison
+MAKE = make
+INSTALL ?= install
+
+CFLAGS += -Wall -O2
+CFLAGS += -D__EXPORTED_HEADERS__ -I$(srctree)/include/uapi -I$(srctree)/include
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+ifeq ($(V),1)
+ Q =
+else
+ Q = @
+endif
+
+FEATURE_USER = .bpf
+FEATURE_TESTS = libbfd disassembler-four-args
+FEATURE_DISPLAY = libbfd disassembler-four-args
+
+check_feat := 1
+NON_CHECK_FEAT_TARGETS := clean bpftool_clean
+ifdef MAKECMDGOALS
+ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),)
+ check_feat := 0
+endif
+endif
+
+ifeq ($(check_feat),1)
+ifeq ($(FEATURES_DUMP),)
+include $(srctree)/tools/build/Makefile.feature
+else
+include $(FEATURES_DUMP)
+endif
+endif
+
+ifeq ($(feature-disassembler-four-args), 1)
+CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
+endif
+
+$(OUTPUT)%.yacc.c: $(srctree)/tools/bpf/%.y
+ $(QUIET_BISON)$(YACC) -o $@ -d $<
+
+$(OUTPUT)%.lex.c: $(srctree)/tools/bpf/%.l
+ $(QUIET_FLEX)$(LEX) -o $@ $<
+
+$(OUTPUT)%.o: $(srctree)/tools/bpf/%.c
+ $(QUIET_CC)$(COMPILE.c) -o $@ $<
+
+$(OUTPUT)%.yacc.o: $(OUTPUT)%.yacc.c
+ $(QUIET_CC)$(COMPILE.c) -o $@ $<
+$(OUTPUT)%.lex.o: $(OUTPUT)%.lex.c
+ $(QUIET_CC)$(COMPILE.c) -o $@ $<
+
+PROGS = $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg $(OUTPUT)bpf_asm
+
+all: $(PROGS) bpftool
+
+$(OUTPUT)bpf_jit_disasm: CFLAGS += -DPACKAGE='bpf_jit_disasm'
+$(OUTPUT)bpf_jit_disasm: $(OUTPUT)bpf_jit_disasm.o
+ $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ -lopcodes -lbfd -ldl
+
+$(OUTPUT)bpf_dbg: $(OUTPUT)bpf_dbg.o
+ $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ -lreadline
+
+$(OUTPUT)bpf_asm: $(OUTPUT)bpf_asm.o $(OUTPUT)bpf_exp.yacc.o $(OUTPUT)bpf_exp.lex.o
+ $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^
+
+$(OUTPUT)bpf_exp.lex.c: $(OUTPUT)bpf_exp.yacc.c
+$(OUTPUT)bpf_exp.yacc.o: $(OUTPUT)bpf_exp.yacc.c
+$(OUTPUT)bpf_exp.lex.o: $(OUTPUT)bpf_exp.lex.c
+
+clean: bpftool_clean
+ $(call QUIET_CLEAN, bpf-progs)
+ $(Q)rm -rf $(OUTPUT)*.o $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg \
+ $(OUTPUT)bpf_asm $(OUTPUT)bpf_exp.yacc.* $(OUTPUT)bpf_exp.lex.*
+ $(call QUIET_CLEAN, core-gen)
+ $(Q)rm -f $(OUTPUT)FEATURE-DUMP.bpf
+
+install: $(PROGS) bpftool_install
+ $(call QUIET_INSTALL, bpf_jit_disasm)
+ $(Q)$(INSTALL) -m 0755 -d $(DESTDIR)$(prefix)/bin
+ $(Q)$(INSTALL) $(OUTPUT)bpf_jit_disasm $(DESTDIR)$(prefix)/bin/bpf_jit_disasm
+ $(call QUIET_INSTALL, bpf_dbg)
+ $(Q)$(INSTALL) $(OUTPUT)bpf_dbg $(DESTDIR)$(prefix)/bin/bpf_dbg
+ $(call QUIET_INSTALL, bpf_asm)
+ $(Q)$(INSTALL) $(OUTPUT)bpf_asm $(DESTDIR)$(prefix)/bin/bpf_asm
+
+bpftool:
+ $(call descend,bpftool)
+
+bpftool_install:
+ $(call descend,bpftool,install)
+
+bpftool_clean:
+ $(call descend,bpftool,clean)
+
+.PHONY: all install clean bpftool bpftool_install bpftool_clean