selftests/bpf: Add a test to confirm PT_REGS_PARM4_SYSCALL

Add a selftest to verify the behavior of PT_REGS_xxx
and the CORE variant.

Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220124141622.4378-4-Kenta.Tada@sony.com

1 files changed, 56 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
new file mode 100644
index 000000000000..c8e60220cda8
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2022 Sony Group Corporation */
+#include <vmlinux.h>
+
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+
+int arg1 = 0;
+unsigned long arg2 = 0;
+unsigned long arg3 = 0;
+unsigned long arg4_cx = 0;
+unsigned long arg4 = 0;
+unsigned long arg5 = 0;
+
+int arg1_core = 0;
+unsigned long arg2_core = 0;
+unsigned long arg3_core = 0;
+unsigned long arg4_core_cx = 0;
+unsigned long arg4_core = 0;
+unsigned long arg5_core = 0;
+
+const volatile pid_t filter_pid = 0;
+
+SEC("kprobe/" SYS_PREFIX "sys_prctl")
+int BPF_KPROBE(handle_sys_prctl)
+{
+	struct pt_regs *real_regs;
+	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+
+	if (pid != filter_pid)
+		return 0;
+
+	real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);
+
+	/* test for PT_REGS_PARM */
+	bpf_probe_read_kernel(&arg1, sizeof(arg1), &PT_REGS_PARM1_SYSCALL(real_regs));
+	bpf_probe_read_kernel(&arg2, sizeof(arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
+	bpf_probe_read_kernel(&arg3, sizeof(arg3), &PT_REGS_PARM3_SYSCALL(real_regs));
+	bpf_probe_read_kernel(&arg4_cx, sizeof(arg4_cx), &PT_REGS_PARM4(real_regs));
+	bpf_probe_read_kernel(&arg4, sizeof(arg4), &PT_REGS_PARM4_SYSCALL(real_regs));
+	bpf_probe_read_kernel(&arg5, sizeof(arg5), &PT_REGS_PARM5_SYSCALL(real_regs));
+
+	/* test for the CORE variant of PT_REGS_PARM */
+	arg1_core = PT_REGS_PARM1_CORE_SYSCALL(real_regs);
+	arg2_core = PT_REGS_PARM2_CORE_SYSCALL(real_regs);
+	arg3_core = PT_REGS_PARM3_CORE_SYSCALL(real_regs);
+	arg4_core_cx = PT_REGS_PARM4_CORE(real_regs);
+	arg4_core = PT_REGS_PARM4_CORE_SYSCALL(real_regs);
+	arg5_core = PT_REGS_PARM5_CORE_SYSCALL(real_regs);
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";