libbpf: Define arm64 syscall regs spec in bpf_tracing.h

Define explicit table of registers used for syscall argument passing.
We need PT_REGS_PARM1_[CORE_]SYSCALL macros overrides, similarly to
s390x, due to orig_x0 not being present in UAPI's pt_regs, so we need to
utilize BPF CO-RE and custom pt_regs___arm64 definition.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Alan Maguire <alan.maguire@oracle.com> # arm64
Link: https://lore.kernel.org/bpf/20230120200914.3008030-18-andrii@kernel.org

tools/lib/bpf/bpf_tracing.h

@@ -233,13 +233,22 @@ struct pt_regs___arm64 {
 #define __PT_PARM6_REG regs[5]
 #define __PT_PARM7_REG regs[6]
 #define __PT_PARM8_REG regs[7]
+
+#define __PT_PARM1_SYSCALL_REG orig_x0
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+#define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1_CORE_SYSCALL(x)
+#define PT_REGS_PARM1_CORE_SYSCALL(x) \
+	BPF_CORE_READ((const struct pt_regs___arm64 *)(x), __PT_PARM1_SYSCALL_REG)
+
 #define __PT_RET_REG regs[30]
 #define __PT_FP_REG regs[29]	/* Works only with CONFIG_FRAME_POINTER */
 #define __PT_RC_REG regs[0]
 #define __PT_SP_REG sp
 #define __PT_IP_REG pc
-#define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1_CORE_SYSCALL(x)
-#define PT_REGS_PARM1_CORE_SYSCALL(x) BPF_CORE_READ((const struct pt_regs___arm64 *)(x), orig_x0)
 
 #elif defined(bpf_target_mips)