selftests/bpf: Add tests for BPF exceptions

Add selftests to cover success and failure cases of API usage, runtime
behavior and invariants that need to be maintained for implementation
correctness.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230912233214.1518551-18-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 135 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/exceptions_assert.c b/tools/testing/selftests/bpf/progs/exceptions_assert.c
new file mode 100644
index 000000000000..fa35832e6748
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/exceptions_assert.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+#include <limits.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_endian.h>
+#include "bpf_misc.h"
+#include "bpf_experimental.h"
+
+#define check_assert(type, op, name, value)				\
+	SEC("?tc")							\
+	__log_level(2) __failure					\
+	int check_assert_##op##_##name(void *ctx)			\
+	{								\
+		type num = bpf_ktime_get_ns();				\
+		bpf_assert_##op(num, value);				\
+		return *(u64 *)num;					\
+	}
+
+__msg(": R0_w=-2147483648 R10=fp0")
+check_assert(s64, eq, int_min, INT_MIN);
+__msg(": R0_w=2147483647 R10=fp0")
+check_assert(s64, eq, int_max, INT_MAX);
+__msg(": R0_w=0 R10=fp0")
+check_assert(s64, eq, zero, 0);
+__msg(": R0_w=-9223372036854775808 R1_w=-9223372036854775808 R10=fp0")
+check_assert(s64, eq, llong_min, LLONG_MIN);
+__msg(": R0_w=9223372036854775807 R1_w=9223372036854775807 R10=fp0")
+check_assert(s64, eq, llong_max, LLONG_MAX);
+
+__msg(": R0_w=scalar(smax=2147483646) R10=fp0")
+check_assert(s64, lt, pos, INT_MAX);
+__msg(": R0_w=scalar(umin=9223372036854775808,var_off=(0x8000000000000000; 0x7fffffffffffffff))")
+check_assert(s64, lt, zero, 0);
+__msg(": R0_w=scalar(umin=9223372036854775808,umax=18446744071562067967,var_off=(0x8000000000000000; 0x7fffffffffffffff))")
+check_assert(s64, lt, neg, INT_MIN);
+
+__msg(": R0_w=scalar(smax=2147483647) R10=fp0")
+check_assert(s64, le, pos, INT_MAX);
+__msg(": R0_w=scalar(smax=0) R10=fp0")
+check_assert(s64, le, zero, 0);
+__msg(": R0_w=scalar(umin=9223372036854775808,umax=18446744071562067968,var_off=(0x8000000000000000; 0x7fffffffffffffff))")
+check_assert(s64, le, neg, INT_MIN);
+
+__msg(": R0_w=scalar(umin=2147483648,umax=9223372036854775807,var_off=(0x0; 0x7fffffffffffffff))")
+check_assert(s64, gt, pos, INT_MAX);
+__msg(": R0_w=scalar(umin=1,umax=9223372036854775807,var_off=(0x0; 0x7fffffffffffffff))")
+check_assert(s64, gt, zero, 0);
+__msg(": R0_w=scalar(smin=-2147483647) R10=fp0")
+check_assert(s64, gt, neg, INT_MIN);
+
+__msg(": R0_w=scalar(umin=2147483647,umax=9223372036854775807,var_off=(0x0; 0x7fffffffffffffff))")
+check_assert(s64, ge, pos, INT_MAX);
+__msg(": R0_w=scalar(umax=9223372036854775807,var_off=(0x0; 0x7fffffffffffffff)) R10=fp0")
+check_assert(s64, ge, zero, 0);
+__msg(": R0_w=scalar(smin=-2147483648) R10=fp0")
+check_assert(s64, ge, neg, INT_MIN);
+
+SEC("?tc")
+__log_level(2) __failure
+__msg(": R0=0 R1=ctx(off=0,imm=0) R2=scalar(smin=-2147483646,smax=2147483645) R10=fp0")
+int check_assert_range_s64(struct __sk_buff *ctx)
+{
+	struct bpf_sock *sk = ctx->sk;
+	s64 num;
+
+	_Static_assert(_Generic((sk->rx_queue_mapping), s32: 1, default: 0), "type match");
+	if (!sk)
+		return 0;
+	num = sk->rx_queue_mapping;
+	bpf_assert_range(num, INT_MIN + 2, INT_MAX - 2);
+	return *((u8 *)ctx + num);
+}
+
+SEC("?tc")
+__log_level(2) __failure
+__msg(": R1=ctx(off=0,imm=0) R2=scalar(umin=4096,umax=8192,var_off=(0x0; 0x3fff))")
+int check_assert_range_u64(struct __sk_buff *ctx)
+{
+	u64 num = ctx->len;
+
+	bpf_assert_range(num, 4096, 8192);
+	return *((u8 *)ctx + num);
+}
+
+SEC("?tc")
+__log_level(2) __failure
+__msg(": R0=0 R1=ctx(off=0,imm=0) R2=4096 R10=fp0")
+int check_assert_single_range_s64(struct __sk_buff *ctx)
+{
+	struct bpf_sock *sk = ctx->sk;
+	s64 num;
+
+	_Static_assert(_Generic((sk->rx_queue_mapping), s32: 1, default: 0), "type match");
+	if (!sk)
+		return 0;
+	num = sk->rx_queue_mapping;
+
+	bpf_assert_range(num, 4096, 4096);
+	return *((u8 *)ctx + num);
+}
+
+SEC("?tc")
+__log_level(2) __failure
+__msg(": R1=ctx(off=0,imm=0) R2=4096 R10=fp0")
+int check_assert_single_range_u64(struct __sk_buff *ctx)
+{
+	u64 num = ctx->len;
+
+	bpf_assert_range(num, 4096, 4096);
+	return *((u8 *)ctx + num);
+}
+
+SEC("?tc")
+__log_level(2) __failure
+__msg(": R1=pkt(off=64,r=64,imm=0) R2=pkt_end(off=0,imm=0) R6=pkt(off=0,r=64,imm=0) R10=fp0")
+int check_assert_generic(struct __sk_buff *ctx)
+{
+	u8 *data_end = (void *)(long)ctx->data_end;
+	u8 *data = (void *)(long)ctx->data;
+
+	bpf_assert(data + 64 <= data_end);
+	return data[128];
+}
+
+SEC("?fentry/bpf_check")
+__failure __msg("At program exit the register R0 has value (0x40; 0x0)")
+int check_assert_with_return(void *ctx)
+{
+	bpf_assert_with(!ctx, 64);
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";