diff mbox series

[RFC,v2,02/31] x86: tracing: Add ftrace_regs definition in the header

Message ID 169945348320.55307.17578137376868880969.stgit@devnote2
State New
Headers
Series tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph |

Commit Message

Masami Hiramatsu (Google) Nov. 8, 2023, 2:24 p.m. UTC 
  From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Add ftrace_regs definition for x86_64 in the ftrace header to
clarify what register will be accessible from ftrace_regs.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 Changes in v2:
  - Newly added.
---
 arch/x86/include/asm/ftrace.h |    6 ++++++
 1 file changed, 6 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 897cf02c20b1..fc60974a1d89 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -36,6 +36,12 @@  static inline unsigned long ftrace_call_adjust(unsigned long addr)
 
 #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
 struct ftrace_regs {
+	/*
+	 * On the x86_64, the ftrace_regs saves;
+	 * rax, rcx, rdx, rdi, rsi, r8, r9, rbp and rsp.
+	 * Also orig_ax is used for passing direct trampoline address.
+	 * x86_32 doesn't support ftrace_regs.
+	 */
 	struct pt_regs		regs;
 };