Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2
3// Copyright (C) 2025 Google LLC.
4
5//! Keep track of statistics for binder_logs.
6
7use crate::defs::*;
8use core::sync::atomic::{AtomicU32, Ordering::Relaxed};
9use kernel::{ioctl::_IOC_NR, seq_file::SeqFile, seq_print};
10
11const BC_COUNT: usize = _IOC_NR(BC_REPLY_SG) as usize + 1;
12const BR_COUNT: usize = _IOC_NR(BR_TRANSACTION_PENDING_FROZEN) as usize + 1;
13
14pub(crate) static GLOBAL_STATS: BinderStats = BinderStats::new();
15
16pub(crate) struct BinderStats {
17 bc: [AtomicU32; BC_COUNT],
18 br: [AtomicU32; BR_COUNT],
19}
20
21impl BinderStats {
22 pub(crate) const fn new() -> Self {
23 #[expect(clippy::declare_interior_mutable_const)]
24 const ZERO: AtomicU32 = AtomicU32::new(0);
25
26 Self {
27 bc: [ZERO; BC_COUNT],
28 br: [ZERO; BR_COUNT],
29 }
30 }
31
32 pub(crate) fn inc_bc(&self, bc: u32) {
33 let idx = _IOC_NR(bc) as usize;
34 if let Some(bc_ref) = self.bc.get(idx) {
35 bc_ref.fetch_add(1, Relaxed);
36 }
37 }
38
39 pub(crate) fn inc_br(&self, br: u32) {
40 let idx = _IOC_NR(br) as usize;
41 if let Some(br_ref) = self.br.get(idx) {
42 br_ref.fetch_add(1, Relaxed);
43 }
44 }
45
46 pub(crate) fn debug_print(&self, prefix: &str, m: &SeqFile) {
47 for (i, cnt) in self.bc.iter().enumerate() {
48 let cnt = cnt.load(Relaxed);
49 if cnt > 0 {
50 seq_print!(m, "{}{}: {}\n", prefix, command_string(i), cnt);
51 }
52 }
53 for (i, cnt) in self.br.iter().enumerate() {
54 let cnt = cnt.load(Relaxed);
55 if cnt > 0 {
56 seq_print!(m, "{}{}: {}\n", prefix, return_string(i), cnt);
57 }
58 }
59 }
60}
61
62mod strings {
63 use core::str::from_utf8_unchecked;
64 use kernel::str::{CStr, CStrExt as _};
65
66 extern "C" {
67 static binder_command_strings: [*const u8; super::BC_COUNT];
68 static binder_return_strings: [*const u8; super::BR_COUNT];
69 }
70
71 pub(super) fn command_string(i: usize) -> &'static str {
72 // SAFETY: Accessing `binder_command_strings` is always safe.
73 let c_str_ptr = unsafe { binder_command_strings[i] };
74 // SAFETY: The `binder_command_strings` array only contains nul-terminated strings.
75 let bytes = unsafe { CStr::from_char_ptr(c_str_ptr) }.to_bytes();
76 // SAFETY: The `binder_command_strings` array only contains strings with ascii-chars.
77 unsafe { from_utf8_unchecked(bytes) }
78 }
79
80 pub(super) fn return_string(i: usize) -> &'static str {
81 // SAFETY: Accessing `binder_return_strings` is always safe.
82 let c_str_ptr = unsafe { binder_return_strings[i] };
83 // SAFETY: The `binder_command_strings` array only contains nul-terminated strings.
84 let bytes = unsafe { CStr::from_char_ptr(c_str_ptr) }.to_bytes();
85 // SAFETY: The `binder_command_strings` array only contains strings with ascii-chars.
86 unsafe { from_utf8_unchecked(bytes) }
87 }
88}
89use strings::{command_string, return_string};