projects/linux·blob master · refs

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1// SPDX-License-Identifier: GPL-2.0
2
3// Copyright (C) 2024, 2025 FUJITA Tomonori <[email protected]>
4
5//! Support for BUG and WARN functionality.
6//!
7//! C header: [`include/asm-generic/bug.h`](srctree/include/asm-generic/bug.h)
8
9#[macro_export]
10#[doc(hidden)]
11#[cfg(not(testlib))]
12#[cfg(all(CONFIG_BUG, not(CONFIG_UML), not(CONFIG_LOONGARCH), not(CONFIG_ARM)))]
13#[cfg(CONFIG_DEBUG_BUGVERBOSE)]
14macro_rules! warn_flags {
15 ($file:expr, $flags:expr) => {
16 const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
17 const _FILE: &[u8] = $file.as_bytes();
18 // Plus one for null-terminator.
19 static FILE: [u8; _FILE.len() + 1] = {
20 let mut bytes = [0; _FILE.len() + 1];
21 let mut i = 0;
22 while i < _FILE.len() {
23 bytes[i] = _FILE[i];
24 i += 1;
25 }
26 bytes
27 };
28
29 // SAFETY:
30 // - `file`, `line`, `flags`, and `size` are all compile-time constants or
31 // symbols, preventing any invalid memory access.
32 // - The asm block has no side effects and does not modify any registers
33 // or memory. It is purely for embedding metadata into the ELF section.
34 unsafe {
35 $crate::asm!(
36 concat!(
37 "/* {size} */",
38 include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
39 include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
40 file = sym FILE,
41 line = const line!(),
42 flags = const FLAGS,
43 size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
44 );
45 }
46 }
47}
48
49#[macro_export]
50#[doc(hidden)]
51#[cfg(not(testlib))]
52#[cfg(all(CONFIG_BUG, not(CONFIG_UML), not(CONFIG_LOONGARCH), not(CONFIG_ARM)))]
53#[cfg(not(CONFIG_DEBUG_BUGVERBOSE))]
54macro_rules! warn_flags {
55 ($file:expr, $flags:expr) => {
56 const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
57
58 if false {
59 _ = $file;
60 }
61
62 // SAFETY:
63 // - `flags` and `size` are all compile-time constants, preventing
64 // any invalid memory access.
65 // - The asm block has no side effects and does not modify any registers
66 // or memory. It is purely for embedding metadata into the ELF section.
67 unsafe {
68 $crate::asm!(
69 concat!(
70 "/* {size} */",
71 include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
72 include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
73 flags = const FLAGS,
74 size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
75 );
76 }
77 }
78}
79
80#[macro_export]
81#[doc(hidden)]
82#[cfg(not(testlib))]
83#[cfg(all(CONFIG_BUG, CONFIG_UML))]
84macro_rules! warn_flags {
85 ($file:expr, $flags:expr) => {
86 if false {
87 _ = $file;
88 }
89
90 // SAFETY: It is always safe to call `warn_slowpath_fmt()`
91 // with a valid null-terminated string.
92 unsafe {
93 $crate::bindings::warn_slowpath_fmt(
94 $crate::str::CStrExt::as_char_ptr($crate::c_str!(::core::file!())),
95 line!() as $crate::ffi::c_int,
96 $flags as $crate::ffi::c_uint,
97 ::core::ptr::null(),
98 );
99 }
100 };
101}
102
103#[macro_export]
104#[doc(hidden)]
105#[cfg(not(testlib))]
106#[cfg(all(CONFIG_BUG, any(CONFIG_LOONGARCH, CONFIG_ARM)))]
107macro_rules! warn_flags {
108 ($file:expr, $flags:expr) => {
109 if false {
110 _ = $file;
111 _ = $flags;
112 }
113
114 // SAFETY: It is always safe to call `WARN_ON()`.
115 unsafe { $crate::bindings::WARN_ON(true) }
116 };
117}
118
119#[macro_export]
120#[doc(hidden)]
121#[cfg(any(testlib, not(CONFIG_BUG)))]
122macro_rules! warn_flags {
123 ($file:expr, $flags:expr) => {
124 if false {
125 _ = $file;
126 _ = $flags;
127 }
128 };
129}
130
131#[doc(hidden)]
132pub const fn bugflag_taint(value: u32) -> u32 {
133 value << 8
134}
135
136/// Report a warning if `cond` is true and return the condition's evaluation result.
137#[macro_export]
138macro_rules! warn_on {
139 ($cond:expr) => {{
140 let cond = $cond;
141
142 #[cfg(CONFIG_DEBUG_BUGVERBOSE_DETAILED)]
143 const COND_STR: &str = concat!("[", stringify!($cond), "] ", file!());
144 #[cfg(not(CONFIG_DEBUG_BUGVERBOSE_DETAILED))]
145 const COND_STR: &str = file!();
146
147 if cond {
148 const WARN_ON_FLAGS: u32 = $crate::bug::bugflag_taint($crate::bindings::TAINT_WARN);
149
150 $crate::warn_flags!(COND_STR, WARN_ON_FLAGS);
151 }
152 cond
153 }};
154}