libbpf: Define powerpc syscall regs spec in bpf_tracing.h

Define explicit table of registers used for syscall argument passing.
Note that 7th arg is supported on 32-bit powerpc architecture, by not on
powerpc64.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230120200914.3008030-20-andrii@kernel.org

tools/lib/bpf/bpf_tracing.h

@@ -294,13 +294,24 @@ struct pt_regs___arm64 {
 #define __PT_PARM6_REG gpr[8]
 #define __PT_PARM7_REG gpr[9]
 #define __PT_PARM8_REG gpr[10]
+
+/* powerpc does not select ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ctx
+#define __PT_PARM1_SYSCALL_REG orig_gpr3
+#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
+#if !defined(__arch64__)
+#define __PT_PARM7_SYSCALL_REG __PT_PARM7_REG /* only powerpc (not powerpc64) */
+#endif
+
 #define __PT_RET_REG regs[31]
 #define __PT_FP_REG __unsupported__
 #define __PT_RC_REG gpr[3]
 #define __PT_SP_REG sp
 #define __PT_IP_REG nip
-/* powerpc does not select ARCH_HAS_SYSCALL_WRAPPER. */
-#define PT_REGS_SYSCALL_REGS(ctx) ctx
 
 #elif defined(bpf_target_sparc)