From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: Wed, 9 Feb 2022 03:17:37 +0100
Subject: libbpf: Add PT_REGS_SYSCALL_REGS macro
Patch-mainline: v5.18-rc1
Git-commit: c5a1ffa0da76da02afc20a0946b594830488b324
References: jsc#PED-1377

Architectures that select ARCH_HAS_SYSCALL_WRAPPER pass a pointer to
struct pt_regs to syscall handlers, others unpack it into individual
function parameters. Introduce a macro to describe what a particular
arch does.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209021745.2215452-3-iii@linux.ibm.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/lib/bpf/bpf_tracing.h |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -326,6 +326,16 @@ struct pt_regs;
 
 #endif /* defined(bpf_target_defined) */
 
+/*
+ * When invoked from a syscall handler kprobe, returns a pointer to a
+ * struct pt_regs containing syscall arguments and suitable for passing to
+ * PT_REGS_PARMn_SYSCALL() and PT_REGS_PARMn_CORE_SYSCALL().
+ */
+#ifndef PT_REGS_SYSCALL_REGS
+/* By default, assume that the arch selects ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ((struct pt_regs *)PT_REGS_PARM1(ctx))
+#endif
+
 #ifndef ___bpf_concat
 #define ___bpf_concat(a, b) a ## b
 #endif