Rust Binder tracepoints

[Darksonn]

C Binder has many tracepoints. Here is one:

linux/drivers/android/binder_trace.h

Lines 22 to 35 in 11439c4

	TRACE_EVENT(binder_ioctl,
	TP_PROTO(unsigned int cmd, unsigned long arg),
	TP_ARGS(cmd, arg),
	TP_STRUCT__entry(
	__field(unsigned int, cmd)
	__field(unsigned long, arg)
	),
	TP_fast_assign(
	__entry->cmd = cmd;
	__entry->arg = arg;
	),
	TP_printk("cmd=0x%x arg=0x%lx", __entry->cmd, __entry->arg)
	);

Rust Binder implements an equivalent one here:

linux/drivers/android/binder/rust_binder_events.h

Lines 18 to 31 in 11439c4

	TRACE_EVENT(rust_binder_ioctl,
	TP_PROTO(unsigned int cmd, unsigned long arg),
	TP_ARGS(cmd, arg),
	TP_STRUCT__entry(
	__field(unsigned int, cmd)
	__field(unsigned long, arg)
	),
	TP_fast_assign(
	__entry->cmd = cmd;
	__entry->arg = arg;
	),
	TP_printk("cmd=0x%x arg=0x%lx", __entry->cmd, __entry->arg)
	);

together with:

linux/drivers/android/binder/trace.rs

Lines 22 to 26 in 11439c4

	#[inline]
	pub(crate) fn trace_ioctl(cmd: u32, arg: usize) {
	// SAFETY: Always safe to call.
	unsafe { rust_binder_ioctl(cmd, arg as c_ulong) }
	}

However, many tracepoints are missing. To work on this issue, pick one of them and submit a patch adding it. Please compare with the implementation found here in Android's fork, but it may need adjustments when upstreamed.

Oh, also, the current tracepoints are called rust_binder_*, but the rust_ prefix should be removed because the name is part of the uapi, and userspace expects tracepoints to have the old names.

[ojeda]

---

This requires submitting a proper patch to the LKML and the Rust for Linux mailing list. Please recall to test your changes (including generating the documentation if changed, running the Rust doctests if changed, etc.), to use a proper title for the commit, to sign your commit under the Developer's Certificate of Origin and to add a Suggested-by: tag, and a Link: tag to this issue. Please see https://docs.kernel.org/process/submitting-patches.html and https://rust-for-linux.com/contributing for details.

[mqqz]

I submitted a patch that added many of the tracepoints in C Binder but not in Rust 🤓

Link: https://lore.kernel.org/rust-for-linux/20260308-rust-binder-trace-v2-0-9e38637a2193@sdhn.cc/