samples/bpf, selftests/bpf: Use bpf_probe_read_kernel

A handful of samples and selftests fail to build on s390, because
after commit 0ebeea8c ("bpf: Restrict bpf_probe_read{, str}()
only to archs where they work") bpf_probe_read is not available
anymore.

Fix by using bpf_probe_read_kernel.
Signed-off-by: NIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720114806.88823-1-iii@linux.ibm.com

samples/bpf/offwaketime_kern.c

@@ -12,7 +12,12 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 
-#define _(P) ({typeof(P) val; bpf_probe_read(&val, sizeof(val), &P); val;})
+#define _(P)                                                                   \
+	({                                                                     \
+		typeof(P) val;                                                 \
+		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \
+		val;                                                           \
+	})
 
 #define MINBLOCK_US	1
 

samples/bpf/test_overhead_kprobe_kern.c

@@ -10,7 +10,12 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 
-#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})
+#define _(P)                                                                   \
+	({                                                                     \
+		typeof(P) val = 0;                                             \
+		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \
+		val;                                                           \
+	})
 
 SEC("kprobe/__set_task_comm")
 int prog(struct pt_regs *ctx)
@@ -25,8 +30,9 @@ int prog(struct pt_regs *ctx)
 	tsk = (void *)PT_REGS_PARM1(ctx);
 
 	pid = _(tsk->pid);
-	bpf_probe_read(oldcomm, sizeof(oldcomm), &tsk->comm);
-	bpf_probe_read(newcomm, sizeof(newcomm), (void *)PT_REGS_PARM2(ctx));
+	bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm);
+	bpf_probe_read_kernel(newcomm, sizeof(newcomm),
+			      (void *)PT_REGS_PARM2(ctx));
 	signal = _(tsk->signal);
 	oom_score_adj = _(signal->oom_score_adj);
 	return 0;

samples/bpf/tracex1_kern.c

@@ -11,7 +11,12 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 
-#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})
+#define _(P)                                                                   \
+	({                                                                     \
+		typeof(P) val = 0;                                             \
+		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \
+		val;                                                           \
+	})
 
 /* kprobe is NOT a stable ABI
  * kernel functions can be removed, renamed or completely change semantics.
@@ -34,7 +39,7 @@ int bpf_prog1(struct pt_regs *ctx)
 	dev = _(skb->dev);
 	len = _(skb->len);
 
-	bpf_probe_read(devname, sizeof(devname), dev->name);
+	bpf_probe_read_kernel(devname, sizeof(devname), dev->name);
 
 	if (devname[0] == 'l' && devname[1] == 'o') {
 		char fmt[] = "skb %p len %d\n";

samples/bpf/tracex5_kern.c

@@ -47,7 +47,7 @@ PROG(SYS__NR_write)(struct pt_regs *ctx)
 {
 	struct seccomp_data sd;
 
-	bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
+	bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
 	if (sd.args[2] == 512) {
 		char fmt[] = "write(fd=%d, buf=%p, size=%d)\n";
 		bpf_trace_printk(fmt, sizeof(fmt),
@@ -60,7 +60,7 @@ PROG(SYS__NR_read)(struct pt_regs *ctx)
 {
 	struct seccomp_data sd;
 
-	bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
+	bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
 	if (sd.args[2] > 128 && sd.args[2] <= 1024) {
 		char fmt[] = "read(fd=%d, buf=%p, size=%d)\n";
 		bpf_trace_printk(fmt, sizeof(fmt),

tools/bpf/bpftool/skeleton/pid_iter.bpf.c

@@ -71,7 +71,8 @@ int iter(struct bpf_iter__task_file *ctx)
 
 	e.pid = task->tgid;
 	e.id = get_obj_id(file->private_data, obj_type);
-	bpf_probe_read(&e.comm, sizeof(e.comm), task->group_leader->comm);
+	bpf_probe_read_kernel(&e.comm, sizeof(e.comm),
+			      task->group_leader->comm);
 	bpf_seq_write(ctx->meta->seq, &e, sizeof(e));
 
 	return 0;

tools/testing/selftests/bpf/progs/bpf_iter_netlink.c

@@ -36,10 +36,10 @@ int dump_netlink(struct bpf_iter__netlink *ctx)
 	if (!nlk->groups)  {
 		group = 0;
 	} else {
-		/* FIXME: temporary use bpf_probe_read here, needs
+		/* FIXME: temporary use bpf_probe_read_kernel here, needs
 		 * verifier support to do direct access.
 		 */
-		bpf_probe_read(&group, sizeof(group), &nlk->groups[0]);
+		bpf_probe_read_kernel(&group, sizeof(group), &nlk->groups[0]);
 	}
 	BPF_SEQ_PRINTF(seq, "%-10u %08x %-8d %-8d %-5d %-8d ",
 		       nlk->portid, (u32)group,
@@ -56,7 +56,7 @@ int dump_netlink(struct bpf_iter__netlink *ctx)
 		 * with current verifier.
 		 */
 		inode = SOCK_INODE(sk);
-		bpf_probe_read(&ino, sizeof(ino), &inode->i_ino);
+		bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
 	}
 	BPF_SEQ_PRINTF(seq, "%-8u %-8lu\n", s->sk_drops.counter, ino);
 

tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c

@@ -57,7 +57,7 @@ static long sock_i_ino(const struct sock *sk)
 		return 0;
 
 	inode = &container_of(sk_socket, struct socket_alloc, socket)->vfs_inode;
-	bpf_probe_read(&ino, sizeof(ino), &inode->i_ino);
+	bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
 	return ino;
 }
 

tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c

@@ -57,7 +57,7 @@ static long sock_i_ino(const struct sock *sk)
 		return 0;
 
 	inode = &container_of(sk_socket, struct socket_alloc, socket)->vfs_inode;
-	bpf_probe_read(&ino, sizeof(ino), &inode->i_ino);
+	bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
 	return ino;
 }
 

tools/testing/selftests/bpf/progs/bpf_iter_udp4.c

@@ -18,7 +18,7 @@ static long sock_i_ino(const struct sock *sk)
 		return 0;
 
 	inode = &container_of(sk_socket, struct socket_alloc, socket)->vfs_inode;
-	bpf_probe_read(&ino, sizeof(ino), &inode->i_ino);
+	bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
 	return ino;
 }
 

tools/testing/selftests/bpf/progs/bpf_iter_udp6.c

@@ -25,7 +25,7 @@ static long sock_i_ino(const struct sock *sk)
 		return 0;
 
 	inode = &container_of(sk_socket, struct socket_alloc, socket)->vfs_inode;
-	bpf_probe_read(&ino, sizeof(ino), &inode->i_ino);
+	bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
 	return ino;
 }