From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- include/acpi/video.h | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 include/acpi/video.h (limited to 'include/acpi/video.h') diff --git a/include/acpi/video.h b/include/acpi/video.h new file mode 100644 index 000000000..044c46313 --- /dev/null +++ b/include/acpi/video.h @@ -0,0 +1,121 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ACPI_VIDEO_H +#define __ACPI_VIDEO_H + +#include /* for ENODEV */ +#include /* for bool */ + +struct acpi_video_brightness_flags { + u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */ + u8 _BCL_reversed:1; /* _BCL package is in a reversed order */ + u8 _BQC_use_index:1; /* _BQC returns an index value */ +}; + +struct acpi_video_device_brightness { + int curr; + int count; + int *levels; + struct acpi_video_brightness_flags flags; +}; + +struct acpi_device; + +#define ACPI_VIDEO_CLASS "video" + +#define ACPI_VIDEO_DISPLAY_CRT 1 +#define ACPI_VIDEO_DISPLAY_TV 2 +#define ACPI_VIDEO_DISPLAY_DVI 3 +#define ACPI_VIDEO_DISPLAY_LCD 4 + +#define ACPI_VIDEO_DISPLAY_LEGACY_MONITOR 0x0100 +#define ACPI_VIDEO_DISPLAY_LEGACY_PANEL 0x0110 +#define ACPI_VIDEO_DISPLAY_LEGACY_TV 0x0200 + +#define ACPI_VIDEO_NOTIFY_SWITCH 0x80 +#define ACPI_VIDEO_NOTIFY_PROBE 0x81 +#define ACPI_VIDEO_NOTIFY_CYCLE 0x82 +#define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT 0x83 +#define ACPI_VIDEO_NOTIFY_PREV_OUTPUT 0x84 +#define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS 0x85 +#define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS 0x86 +#define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS 0x87 +#define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS 0x88 +#define ACPI_VIDEO_NOTIFY_DISPLAY_OFF 0x89 + +enum acpi_backlight_type { + acpi_backlight_undef = -1, + acpi_backlight_none = 0, + acpi_backlight_video, + acpi_backlight_vendor, + acpi_backlight_native, + acpi_backlight_nvidia_wmi_ec, + acpi_backlight_apple_gmux, + acpi_backlight_dell_uart, +}; + +#if IS_ENABLED(CONFIG_ACPI_VIDEO) +extern int acpi_video_register(void); +extern void acpi_video_unregister(void); +extern void acpi_video_register_backlight(void); +extern int acpi_video_get_edid(struct acpi_device *device, int type, + int device_id, void **edid); +/* + * Note: The value returned by acpi_video_handles_brightness_key_presses() + * may change over time and should not be cached. + */ +extern bool acpi_video_handles_brightness_key_presses(void); +extern int acpi_video_get_levels(struct acpi_device *device, + struct acpi_video_device_brightness **dev_br, + int *pmax_level); + +extern enum acpi_backlight_type __acpi_video_get_backlight_type(bool native, + bool *auto_detect); + +static inline enum acpi_backlight_type acpi_video_get_backlight_type(void) +{ + return __acpi_video_get_backlight_type(false, NULL); +} + +/* + * This function MUST only be called by GPU drivers to check if the driver + * should register a backlight class device. This function not only checks + * if a GPU native backlight device should be registered it *also* tells + * the ACPI video-detect code that native GPU backlight control is available. + * Therefor calling this from any place other then the GPU driver is wrong! + * To check if GPU native backlight control is used in other places instead use: + * if (acpi_video_get_backlight_type() == acpi_backlight_native) { ... } + */ +static inline bool acpi_video_backlight_use_native(void) +{ + return __acpi_video_get_backlight_type(true, NULL) == acpi_backlight_native; +} +#else +static inline int acpi_video_register(void) { return -ENODEV; } +static inline void acpi_video_unregister(void) { return; } +static inline void acpi_video_register_backlight(void) { return; } +static inline int acpi_video_get_edid(struct acpi_device *device, int type, + int device_id, void **edid) +{ + return -ENODEV; +} +static inline enum acpi_backlight_type acpi_video_get_backlight_type(void) +{ + return acpi_backlight_vendor; +} +static inline bool acpi_video_backlight_use_native(void) +{ + return true; +} +static inline bool acpi_video_handles_brightness_key_presses(void) +{ + return false; +} +static inline int acpi_video_get_levels(struct acpi_device *device, + struct acpi_video_device_brightness **dev_br, + int *pmax_level) +{ + return -ENODEV; +} +#endif + +#endif -- cgit v1.3.1