[v3,4/5] print: use new #[export] macro for rust_fmt_argument

Commit Message

Alice Ryhl March 3, 2025, 8:45 a.m. UTC

This moves the rust_fmt_argument function over to use the new #[export]
macro, which will verify at compile-time that the function signature
matches what is in the header file.

Reviewed-by: Andreas Hindborg <[e-mail]>
Reviewed-by: Tamir Duberstein <[e-mail]>
Acked-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Alice Ryhl <[e-mail]>
---
 include/linux/sprintf.h | 3 +++
 lib/vsprintf.c          | 3 ---
 rust/kernel/print.rs    | 3 ++-
 3 files changed, 5 insertions(+), 4 deletions(-)

Comments

Andy Shevchenko March 3, 2025, 9:46 a.m. UTC | #1

On Mon, Mar 03, 2025 at 08:45:15AM +0000, Alice Ryhl wrote:
> This moves the rust_fmt_argument function over to use the new #[export]
> macro, which will verify at compile-time that the function signature
> matches what is in the header file.

...

>  extern bool no_hash_pointers;
>  int no_hash_pointers_enable(char *str);
>  
> +/* Used for Rust formatting ('%pA'). */

In case you need a new version, please drop a period at the end as this is the
style used in the sprintf.h already.

> +char *rust_fmt_argument(char *buf, char *end, const void *ptr);

Alice Ryhl March 3, 2025, 9:49 a.m. UTC | #2

On Mon, Mar 3, 2025 at 10:46 AM Andy Shevchenko
<[e-mail]> wrote:
>
> On Mon, Mar 03, 2025 at 08:45:15AM +0000, Alice Ryhl wrote:
> > This moves the rust_fmt_argument function over to use the new #[export]
> > macro, which will verify at compile-time that the function signature
> > matches what is in the header file.
>
> ...
>
> >  extern bool no_hash_pointers;
> >  int no_hash_pointers_enable(char *str);
> >
> > +/* Used for Rust formatting ('%pA'). */
>
> In case you need a new version, please drop a period at the end as this is the
> style used in the sprintf.h already.

Sure, I will remove the period if I send a new version.

Alice

Petr Mladek March 3, 2025, 10:40 a.m. UTC | #3

On Mon 2025-03-03 08:45:15, Alice Ryhl wrote:
> This moves the rust_fmt_argument function over to use the new #[export]
> macro, which will verify at compile-time that the function signature
> matches what is in the header file.
> 
> Reviewed-by: Andreas Hindborg <[e-mail]>
> Reviewed-by: Tamir Duberstein <[e-mail]>
> Acked-by: Greg Kroah-Hartman <[e-mail]>
> Signed-off-by: Alice Ryhl <[e-mail]>

Acked-by: Petr Mladek <[e-mail]>

Best Regards,
Petr

Patch

diff --git a/include/linux/sprintf.h b/include/linux/sprintf.h
index 33dcbec71925..029ad83efd74 100644
--- a/include/linux/sprintf.h
+++ b/include/linux/sprintf.h
@@ -24,4 +24,7 @@  __scanf(2, 0) int vsscanf(const char *, const char *, va_list);
 extern bool no_hash_pointers;
 int no_hash_pointers_enable(char *str);
 
+/* Used for Rust formatting ('%pA'). */
+char *rust_fmt_argument(char *buf, char *end, const void *ptr);
+
 #endif	/* _LINUX_KERNEL_SPRINTF_H */
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index a8ac4c4fffcf..1da61c3e011f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2284,9 +2284,6 @@  int __init no_hash_pointers_enable(char *str)
 }
 early_param("no_hash_pointers", no_hash_pointers_enable);
 
-/* Used for Rust formatting ('%pA'). */
-char *rust_fmt_argument(char *buf, char *end, const void *ptr);
-
 /*
  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
  * by an extra set of alphanumeric characters that are extended format
diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs
index 61ee36c5e5f5..cf4714242e14 100644
--- a/rust/kernel/print.rs
+++ b/rust/kernel/print.rs
@@ -8,13 +8,14 @@ 
 
 use crate::{
     ffi::{c_char, c_void},
+    prelude::*,
     str::RawFormatter,
 };
 use core::fmt;
 
 // Called from `vsprintf` with format specifier `%pA`.
 #[expect(clippy::missing_safety_doc)]
-#[no_mangle]
+#[export]
 unsafe extern "C" fn rust_fmt_argument(
     buf: *mut c_char,
     end: *mut c_char,