[PATCH bpf-next v4 14/14] arm64: add a comment that warns that orig_x0 should not be moved

[Ilya Leoshkevich <iii@xxxxxxxxxxxxx>]

orig_x0's location is used by libbpf tracing macros, therefore it
should not be moved.

Suggested-by: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
---
 arch/arm64/include/asm/ptrace.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 41b332c054ab..7e34c3737839 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -185,6 +185,10 @@ struct pt_regs {
 			u64 pstate;
 		};
 	};
+	/*
+	 * orig_x0 is not exposed via struct user_pt_regs, but its location is
+	 * assumed by libbpf's tracing macros, so it should not be moved.
+	 */
 	u64 orig_x0;
 #ifdef __AARCH64EB__
 	u32 unused2;
-- 
2.34.1