Merge branch 'bpf-helper-cleanups'

Daniel Borkmann says:

====================
Some BPF helper cleanups

This series contains a couple of misc cleanups and improvements
for BPF helpers. For details please see individual patches. We
let this also sit for a few days with Fengguang's kbuild test
robot, and there were no issues seen (besides one false positive,
see last one for details).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/filter.h

@@ -314,6 +314,70 @@ struct bpf_prog_aux;
 	bpf_size;						\
 })
 
+#define BPF_SIZEOF(type)					\
+	({							\
+		const int __size = bytes_to_bpf_size(sizeof(type)); \
+		BUILD_BUG_ON(__size < 0);			\
+		__size;						\
+	})
+
+#define BPF_FIELD_SIZEOF(type, field)				\
+	({							\
+		const int __size = bytes_to_bpf_size(FIELD_SIZEOF(type, field)); \
+		BUILD_BUG_ON(__size < 0);			\
+		__size;						\
+	})
+
+#define __BPF_MAP_0(m, v, ...) v
+#define __BPF_MAP_1(m, v, t, a, ...) m(t, a)
+#define __BPF_MAP_2(m, v, t, a, ...) m(t, a), __BPF_MAP_1(m, v, __VA_ARGS__)
+#define __BPF_MAP_3(m, v, t, a, ...) m(t, a), __BPF_MAP_2(m, v, __VA_ARGS__)
+#define __BPF_MAP_4(m, v, t, a, ...) m(t, a), __BPF_MAP_3(m, v, __VA_ARGS__)
+#define __BPF_MAP_5(m, v, t, a, ...) m(t, a), __BPF_MAP_4(m, v, __VA_ARGS__)
+
+#define __BPF_REG_0(...) __BPF_PAD(5)
+#define __BPF_REG_1(...) __BPF_MAP(1, __VA_ARGS__), __BPF_PAD(4)
+#define __BPF_REG_2(...) __BPF_MAP(2, __VA_ARGS__), __BPF_PAD(3)
+#define __BPF_REG_3(...) __BPF_MAP(3, __VA_ARGS__), __BPF_PAD(2)
+#define __BPF_REG_4(...) __BPF_MAP(4, __VA_ARGS__), __BPF_PAD(1)
+#define __BPF_REG_5(...) __BPF_MAP(5, __VA_ARGS__)
+
+#define __BPF_MAP(n, ...) __BPF_MAP_##n(__VA_ARGS__)
+#define __BPF_REG(n, ...) __BPF_REG_##n(__VA_ARGS__)
+
+#define __BPF_CAST(t, a)						       \
+	(__force t)							       \
+	(__force							       \
+	 typeof(__builtin_choose_expr(sizeof(t) == sizeof(unsigned long),      \
+				      (unsigned long)0, (t)0))) a
+#define __BPF_V void
+#define __BPF_N
+
+#define __BPF_DECL_ARGS(t, a) t   a
+#define __BPF_DECL_REGS(t, a) u64 a
+
+#define __BPF_PAD(n)							       \
+	__BPF_MAP(n, __BPF_DECL_ARGS, __BPF_N, u64, __ur_1, u64, __ur_2,       \
+		  u64, __ur_3, u64, __ur_4, u64, __ur_5)
+
+#define BPF_CALL_x(x, name, ...)					       \
+	static __always_inline						       \
+	u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__));   \
+	u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__));	       \
+	u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__))	       \
+	{								       \
+		return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
+	}								       \
+	static __always_inline						       \
+	u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))
+
+#define BPF_CALL_0(name, ...)	BPF_CALL_x(0, name, __VA_ARGS__)
+#define BPF_CALL_1(name, ...)	BPF_CALL_x(1, name, __VA_ARGS__)
+#define BPF_CALL_2(name, ...)	BPF_CALL_x(2, name, __VA_ARGS__)
+#define BPF_CALL_3(name, ...)	BPF_CALL_x(3, name, __VA_ARGS__)
+#define BPF_CALL_4(name, ...)	BPF_CALL_x(4, name, __VA_ARGS__)
+#define BPF_CALL_5(name, ...)	BPF_CALL_x(5, name, __VA_ARGS__)
+
 #ifdef CONFIG_COMPAT
 /* A struct sock_filter is architecture independent. */
 struct compat_sock_fprog {

kernel/bpf/core.c

@@ -1018,7 +1018,7 @@ void bpf_user_rnd_init_once(void)
 	prandom_init_once(&bpf_user_rnd_state);
 }
 
-u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_0(bpf_user_rnd_u32)
 {
 	/* Should someone ever have the rather unwise idea to use some
 	 * of the registers passed into this function, then note that

kernel/bpf/helpers.c

@@ -16,6 +16,7 @@
 #include <linux/ktime.h>
 #include <linux/sched.h>
 #include <linux/uidgid.h>
+#include <linux/filter.h>
 
 /* If kernel subsystem is allowing eBPF programs to call this function,
  * inside its own verifier_ops->get_func_proto() callback it should return
@@ -26,24 +27,10 @@
  * if program is allowed to access maps, so check rcu_read_lock_held in
  * all three functions.
  */
-static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
 {
-	/* verifier checked that R1 contains a valid pointer to bpf_map
-	 * and R2 points to a program stack and map->key_size bytes were
-	 * initialized
-	 */
-	struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
-	void *key = (void *) (unsigned long) r2;
-	void *value;
-
 	WARN_ON_ONCE(!rcu_read_lock_held());
-
-	value = map->ops->map_lookup_elem(map, key);
-
-	/* lookup() returns either pointer to element value or NULL
-	 * which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type
-	 */
-	return (unsigned long) value;
+	return (unsigned long) map->ops->map_lookup_elem(map, key);
 }
 
 const struct bpf_func_proto bpf_map_lookup_elem_proto = {
@@ -54,15 +41,11 @@ const struct bpf_func_proto bpf_map_lookup_elem_proto = {
 	.arg2_type	= ARG_PTR_TO_MAP_KEY,
 };
 
-static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
+	   void *, value, u64, flags)
 {
-	struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
-	void *key = (void *) (unsigned long) r2;
-	void *value = (void *) (unsigned long) r3;
-
 	WARN_ON_ONCE(!rcu_read_lock_held());
-
-	return map->ops->map_update_elem(map, key, value, r4);
+	return map->ops->map_update_elem(map, key, value, flags);
 }
 
 const struct bpf_func_proto bpf_map_update_elem_proto = {
@@ -75,13 +58,9 @@ const struct bpf_func_proto bpf_map_update_elem_proto = {
 	.arg4_type	= ARG_ANYTHING,
 };
 
-static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
 {
-	struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
-	void *key = (void *) (unsigned long) r2;
-
 	WARN_ON_ONCE(!rcu_read_lock_held());
-
 	return map->ops->map_delete_elem(map, key);
 }
 
@@ -99,7 +78,7 @@ const struct bpf_func_proto bpf_get_prandom_u32_proto = {
 	.ret_type	= RET_INTEGER,
 };
 
-static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_0(bpf_get_smp_processor_id)
 {
 	return smp_processor_id();
 }
@@ -110,7 +89,7 @@ const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
 	.ret_type	= RET_INTEGER,
 };
 
-static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_0(bpf_ktime_get_ns)
 {
 	/* NMI safe access to clock monotonic */
 	return ktime_get_mono_fast_ns();
@@ -122,11 +101,11 @@ const struct bpf_func_proto bpf_ktime_get_ns_proto = {
 	.ret_type	= RET_INTEGER,
 };
 
-static u64 bpf_get_current_pid_tgid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_0(bpf_get_current_pid_tgid)
 {
 	struct task_struct *task = current;
 
-	if (!task)
+	if (unlikely(!task))
 		return -EINVAL;
 
 	return (u64) task->tgid << 32 | task->pid;
@@ -138,18 +117,18 @@ const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
 	.ret_type	= RET_INTEGER,
 };
 
-static u64 bpf_get_current_uid_gid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+BPF_CALL_0(bpf_get_current_uid_gid)
 {
 	struct task_struct *task = current;
 	kuid_t uid;
 	kgid_t gid;
 
-	if (!task)
+	if (unlikely(!task))
 		return -EINVAL;
 
 	current_uid_gid(&uid, &gid);
 	return (u64) from_kgid(&init_user_ns, gid) << 32 |
-		from_kuid(&init_user_ns, uid);
+		     from_kuid(&init_user_ns, uid);
 }
 
 const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
@@ -158,10 +137,9 @@ const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
 	.ret_type	= RET_INTEGER,
 };
 
-static u64 bpf_get_current_comm(u64 r1, u64 size, u64 r3, u64 r4, u64 r5)
+BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
 {
 	struct task_struct *task = current;
-	char *buf = (char *) (long) r1;
 
 	if (unlikely(!task))
 		goto err_clear;

kernel/bpf/stackmap.c

@@ -116,10 +116,9 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
 	return ERR_PTR(err);
 }
 
-u64 bpf_get_stackid(u64 r1, u64 r2, u64 flags, u64 r4, u64 r5)
+BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map,
+	   u64, flags)
 {
-	struct pt_regs *regs = (struct pt_regs *) (long) r1;
-	struct bpf_map *map = (struct bpf_map *) (long) r2;
 	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
 	struct perf_callchain_entry *trace;
 	struct stack_map_bucket *bucket, *new_bucket, *old_bucket;