bpf: add initial suite for selftests

Add a start of a test suite for kernel selftests. This moves test_verifier
and test_maps over to tools/testing/selftests/bpf/ along with various
code improvements and also adds a script for invoking test_bpf module.
The test suite can simply be run via selftest framework, f.e.:

  # cd tools/testing/selftests/bpf/
  # make
  # make run_tests

Both test_verifier and test_maps were kind of misplaced in samples/bpf/
directory and we were looking into adding them to selftests for a while
now, so it can be picked up by kbuild bot et al and hopefully also get
more exposure and thus new test case additions.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -2521,6 +2521,8 @@ L:	netdev@vger.kernel.org
 L:	linux-kernel@vger.kernel.org
 S:	Supported
 F:	kernel/bpf/
+F:	tools/testing/selftests/bpf/
+F:	lib/test_bpf.c
 
 BROADCOM B44 10/100 ETHERNET DRIVER
 M:	Michael Chan <michael.chan@broadcom.com>
@@ -8413,7 +8415,6 @@ F:	include/uapi/linux/net_namespace.h
 F:	tools/net/
 F:	tools/testing/selftests/net/
 F:	lib/random32.c
-F:	lib/test_bpf.c
 
 NETWORKING [IPv4/IPv6]
 M:	"David S. Miller" <davem@davemloft.net>

samples/bpf/Makefile

@@ -2,7 +2,6 @@
 obj- := dummy.o
 
 # List of programs to build
-hostprogs-y := test_verifier test_maps
 hostprogs-y += sock_example
 hostprogs-y += fds_example
 hostprogs-y += sockex1
@@ -28,8 +27,6 @@ hostprogs-y += test_current_task_under_cgroup
 hostprogs-y += trace_event
 hostprogs-y += sampleip
 
-test_verifier-objs := test_verifier.o libbpf.o
-test_maps-objs := test_maps.o libbpf.o
 sock_example-objs := sock_example.o libbpf.o
 fds_example-objs := bpf_load.o libbpf.o fds_example.o
 sockex1-objs := bpf_load.o libbpf.o sockex1_user.o

tools/include/linux/filter.h

@@ -218,6 +218,30 @@
 		.off   = OFF,					\
 		.imm   = IMM })
 
+/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
+
+#define BPF_LD_IMM64(DST, IMM)					\
+	BPF_LD_IMM64_RAW(DST, 0, IMM)
+
+#define BPF_LD_IMM64_RAW(DST, SRC, IMM)				\
+	((struct bpf_insn) {					\
+		.code  = BPF_LD | BPF_DW | BPF_IMM,		\
+		.dst_reg = DST,					\
+		.src_reg = SRC,					\
+		.off   = 0,					\
+		.imm   = (__u32) (IMM) }),			\
+	((struct bpf_insn) {					\
+		.code  = 0, /* zero is reserved opcode */	\
+		.dst_reg = 0,					\
+		.src_reg = 0,					\
+		.off   = 0,					\
+		.imm   = ((__u64) (IMM)) >> 32 })
+
+/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
+
+#define BPF_LD_MAP_FD(DST, MAP_FD)				\
+	BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
+
 /* Program exit */
 
 #define BPF_EXIT_INSN()						\

tools/testing/selftests/Makefile

@@ -1,4 +1,5 @@
-TARGETS = breakpoints
+TARGETS =  bpf
+TARGETS += breakpoints
 TARGETS += capabilities
 TARGETS += cpu-hotplug
 TARGETS += efivarfs

tools/testing/selftests/bpf/.gitignore

@@ -0,0 +1,2 @@
+test_verifier
+test_maps

tools/testing/selftests/bpf/Makefile

@@ -0,0 +1,13 @@
+CFLAGS += -Wall -O2
+
+test_objs = test_verifier test_maps
+
+TEST_PROGS := test_verifier test_maps test_kmod.sh
+TEST_FILES := $(test_objs)
+
+all: $(test_objs)
+
+include ../lib.mk
+
+clean:
+	$(RM) $(test_objs)

tools/testing/selftests/bpf/bpf_sys.h

@@ -0,0 +1,108 @@
+#ifndef __BPF_SYS__
+#define __BPF_SYS__
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include <sys/syscall.h>
+
+#include <linux/bpf.h>
+
+static inline __u64 bpf_ptr_to_u64(const void *ptr)
+{
+	return (__u64)(unsigned long) ptr;
+}
+
+static inline int bpf(int cmd, union bpf_attr *attr, unsigned int size)
+{
+#ifdef __NR_bpf
+	return syscall(__NR_bpf, cmd, attr, size);
+#else
+	fprintf(stderr, "No bpf syscall, kernel headers too old?\n");
+	errno = ENOSYS;
+	return -1;
+#endif
+}
+
+static inline int bpf_map_lookup(int fd, const void *key, void *value)
+{
+	union bpf_attr attr = {};
+
+	attr.map_fd = fd;
+	attr.key = bpf_ptr_to_u64(key);
+	attr.value = bpf_ptr_to_u64(value);
+
+	return bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
+}
+
+static inline int bpf_map_update(int fd, const void *key, const void *value,
+				 uint64_t flags)
+{
+	union bpf_attr attr = {};
+
+	attr.map_fd = fd;
+	attr.key = bpf_ptr_to_u64(key);
+	attr.value = bpf_ptr_to_u64(value);
+	attr.flags = flags;
+
+	return bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
+}
+
+static inline int bpf_map_delete(int fd, const void *key)
+{
+	union bpf_attr attr = {};
+
+	attr.map_fd = fd;
+	attr.key = bpf_ptr_to_u64(key);
+
+	return bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
+}
+
+static inline int bpf_map_next_key(int fd, const void *key, void *next_key)
+{
+	union bpf_attr attr = {};
+
+	attr.map_fd = fd;
+	attr.key = bpf_ptr_to_u64(key);
+	attr.next_key = bpf_ptr_to_u64(next_key);
+
+	return bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
+}
+
+static inline int bpf_map_create(enum bpf_map_type type, uint32_t size_key,
+				 uint32_t size_value, uint32_t max_elem,
+				 uint32_t flags)
+{
+	union bpf_attr attr = {};
+
+	attr.map_type = type;
+	attr.key_size = size_key;
+	attr.value_size = size_value;
+	attr.max_entries = max_elem;
+	attr.map_flags = flags;
+
+	return bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
+}
+
+static inline int bpf_prog_load(enum bpf_prog_type type,
+				const struct bpf_insn *insns, size_t size_insns,
+				const char *license, char *log, size_t size_log)
+{
+	union bpf_attr attr = {};
+
+	attr.prog_type = type;
+	attr.insns = bpf_ptr_to_u64(insns);
+	attr.insn_cnt = size_insns / sizeof(struct bpf_insn);
+	attr.license = bpf_ptr_to_u64(license);
+
+	if (size_log > 0) {
+		attr.log_buf = bpf_ptr_to_u64(log);
+		attr.log_size = size_log;
+		attr.log_level = 1;
+		log[0] = 0;
+	}
+
+	return bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+}
+
+#endif /* __BPF_SYS__ */

tools/testing/selftests/bpf/config

@@ -0,0 +1,5 @@
+CONFIG_BPF=y
+CONFIG_BPF_SYSCALL=y
+CONFIG_NET_CLS_BPF=m
+CONFIG_BPF_EVENTS=y
+CONFIG_TEST_BPF=m

tools/testing/selftests/bpf/test_kmod.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+SRC_TREE=../../../../
+
+test_run()
+{
+	sysctl -w net.core.bpf_jit_enable=$1 2>&1 > /dev/null
+	sysctl -w net.core.bpf_jit_harden=$2 2>&1 > /dev/null
+
+	echo "[ JIT enabled:$1 hardened:$2 ]"
+	dmesg -C
+	insmod $SRC_TREE/lib/test_bpf.ko 2> /dev/null
+	if [ $? -ne 0 ]; then
+		rc=1
+	fi
+	rmmod  test_bpf 2> /dev/null
+	dmesg | grep FAIL
+}
+
+test_save()
+{
+	JE=`sysctl -n net.core.bpf_jit_enable`
+	JH=`sysctl -n net.core.bpf_jit_harden`
+}
+
+test_restore()
+{
+	sysctl -w net.core.bpf_jit_enable=$JE 2>&1 > /dev/null
+	sysctl -w net.core.bpf_jit_harden=$JH 2>&1 > /dev/null
+}
+
+rc=0
+test_save
+test_run 0 0
+test_run 1 0
+test_run 1 1
+test_run 1 2
+test_restore
+exit $rc