From fc2f191f850d9a2fb1b78c51d49076e60fb42c49 Mon Sep 17 00:00:00 2001 From: Alice Ryhl Date: Mon, 3 Mar 2025 08:45:16 +0000 Subject: [PATCH] panic_qr: use new #[export] macro This validates at compile time that the signatures match what is in the header file. It highlights one annoyance with the compile-time check, which is that it can only be used with functions marked unsafe. If the function is not unsafe, then this error is emitted: error[E0308]: `if` and `else` have incompatible types --> /drivers/gpu/drm/drm_panic_qr.rs:987:19 | 986 | #[export] | --------- expected because of this 987 | pub extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize { | ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected unsafe fn, found safe fn | = note: expected fn item `unsafe extern "C" fn(_, _) -> _ {kernel::bindings::drm_panic_qr_max_data_size}` found fn item `extern "C" fn(_, _) -> _ {drm_panic_qr_max_data_size}` The signature declarations are moved to a header file so it can be included in the Rust bindings helper, and the extern keyword is removed as it is unnecessary. Reviewed-by: Andreas Hindborg Reviewed-by: Tamir Duberstein Acked-by: Simona Vetter Acked-by: Greg Kroah-Hartman Signed-off-by: Alice Ryhl Reviewed-by: Jocelyn Falempe Link: https://lore.kernel.org/r/20250303-export-macro-v3-5-41fbad85a27f@google.com [ Fixed `rustfmt`. Moved on top the unsafe requirement comment to follow the usual style, and slightly reworded it for clarity. Formatted bindings helper comment. - Miguel ] Signed-off-by: Miguel Ojeda --- drivers/gpu/drm/drm_panic.c | 5 ----- drivers/gpu/drm/drm_panic_qr.rs | 13 +++++++++---- include/drm/drm_panic.h | 7 +++++++ rust/bindings/bindings_helper.h | 5 +++++ 4 files changed, 21 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index f128d345b16df..dee5301dd7299 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -486,11 +486,6 @@ static void drm_panic_qr_exit(void) stream.workspace = NULL; } -extern size_t drm_panic_qr_max_data_size(u8 version, size_t url_len); - -extern u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size, - u8 *tmp, size_t tmp_size); - static int drm_panic_get_qr_code_url(u8 **qr_image) { struct kmsg_dump_iter iter; diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs index bcf248f69252c..ecd87e8ffe05a 100644 --- a/drivers/gpu/drm/drm_panic_qr.rs +++ b/drivers/gpu/drm/drm_panic_qr.rs @@ -27,7 +27,7 @@ //! * use core::cmp; -use kernel::str::CStr; +use kernel::{prelude::*, str::CStr}; #[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd)] struct Version(usize); @@ -929,7 +929,7 @@ impl QrImage<'_> { /// * `tmp` must be valid for reading and writing for `tmp_size` bytes. /// /// They must remain valid for the duration of the function call. -#[no_mangle] +#[export] pub unsafe extern "C" fn drm_panic_qr_generate( url: *const kernel::ffi::c_char, data: *mut u8, @@ -980,8 +980,13 @@ pub unsafe extern "C" fn drm_panic_qr_generate( /// * If `url_len` > 0, remove the 2 segments header/length and also count the /// conversion to numeric segments. /// * If `url_len` = 0, only removes 3 bytes for 1 binary segment. -#[no_mangle] -pub extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize { +/// +/// # Safety +/// +/// Always safe to call. +// Required to be unsafe due to the `#[export]` annotation. +#[export] +pub unsafe extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize { #[expect(clippy::manual_range_contains)] if version < 1 || version > 40 { return 0; diff --git a/include/drm/drm_panic.h b/include/drm/drm_panic.h index f4e1fa9ae607a..ff78d00c3da50 100644 --- a/include/drm/drm_panic.h +++ b/include/drm/drm_panic.h @@ -163,4 +163,11 @@ static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) #endif +#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE) +size_t drm_panic_qr_max_data_size(u8 version, size_t url_len); + +u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size, + u8 *tmp, size_t tmp_size); +#endif + #endif /* __DRM_PANIC_H__ */ diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index f46cf3bb70695..ae39fc18a8bf0 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -37,6 +37,11 @@ #include #include +#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE) +// Used by `#[export]` in `drivers/gpu/drm/drm_panic_qr.rs`. +#include +#endif + /* `bindgen` gets confused at certain things. */ const size_t RUST_CONST_HELPER_ARCH_SLAB_MINALIGN = ARCH_SLAB_MINALIGN; const size_t RUST_CONST_HELPER_PAGE_SIZE = PAGE_SIZE; -- 2.50.1