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/drm/drm_eld.h | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 164 insertions(+) create mode 100644 include/drm/drm_eld.h (limited to 'include/drm/drm_eld.h') diff --git a/include/drm/drm_eld.h b/include/drm/drm_eld.h new file mode 100644 index 000000000..0a88d10b2 --- /dev/null +++ b/include/drm/drm_eld.h @@ -0,0 +1,164 @@ +/* SPDX-License-Identifier: MIT */ +/* + * Copyright © 2023 Intel Corporation + */ + +#ifndef __DRM_ELD_H__ +#define __DRM_ELD_H__ + +#include + +struct cea_sad; + +/* ELD Header Block */ +#define DRM_ELD_HEADER_BLOCK_SIZE 4 + +#define DRM_ELD_VER 0 +# define DRM_ELD_VER_SHIFT 3 +# define DRM_ELD_VER_MASK (0x1f << 3) +# define DRM_ELD_VER_CEA861D (2 << 3) /* supports 861D or below */ +# define DRM_ELD_VER_CANNED (0x1f << 3) + +#define DRM_ELD_BASELINE_ELD_LEN 2 /* in dwords! */ + +/* ELD Baseline Block for ELD_Ver == 2 */ +#define DRM_ELD_CEA_EDID_VER_MNL 4 +# define DRM_ELD_CEA_EDID_VER_SHIFT 5 +# define DRM_ELD_CEA_EDID_VER_MASK (7 << 5) +# define DRM_ELD_CEA_EDID_VER_NONE (0 << 5) +# define DRM_ELD_CEA_EDID_VER_CEA861 (1 << 5) +# define DRM_ELD_CEA_EDID_VER_CEA861A (2 << 5) +# define DRM_ELD_CEA_EDID_VER_CEA861BCD (3 << 5) +# define DRM_ELD_MNL_SHIFT 0 +# define DRM_ELD_MNL_MASK (0x1f << 0) + +#define DRM_ELD_SAD_COUNT_CONN_TYPE 5 +# define DRM_ELD_SAD_COUNT_SHIFT 4 +# define DRM_ELD_SAD_COUNT_MASK (0xf << 4) +# define DRM_ELD_CONN_TYPE_SHIFT 2 +# define DRM_ELD_CONN_TYPE_MASK (3 << 2) +# define DRM_ELD_CONN_TYPE_HDMI (0 << 2) +# define DRM_ELD_CONN_TYPE_DP (1 << 2) +# define DRM_ELD_SUPPORTS_AI (1 << 1) +# define DRM_ELD_SUPPORTS_HDCP (1 << 0) + +#define DRM_ELD_AUD_SYNCH_DELAY 6 /* in units of 2 ms */ +# define DRM_ELD_AUD_SYNCH_DELAY_MAX 0xfa /* 500 ms */ + +#define DRM_ELD_SPEAKER 7 +# define DRM_ELD_SPEAKER_MASK 0x7f +# define DRM_ELD_SPEAKER_RLRC (1 << 6) +# define DRM_ELD_SPEAKER_FLRC (1 << 5) +# define DRM_ELD_SPEAKER_RC (1 << 4) +# define DRM_ELD_SPEAKER_RLR (1 << 3) +# define DRM_ELD_SPEAKER_FC (1 << 2) +# define DRM_ELD_SPEAKER_LFE (1 << 1) +# define DRM_ELD_SPEAKER_FLR (1 << 0) + +#define DRM_ELD_PORT_ID 8 /* offsets 8..15 inclusive */ +# define DRM_ELD_PORT_ID_LEN 8 + +#define DRM_ELD_MANUFACTURER_NAME0 16 +#define DRM_ELD_MANUFACTURER_NAME1 17 + +#define DRM_ELD_PRODUCT_CODE0 18 +#define DRM_ELD_PRODUCT_CODE1 19 + +#define DRM_ELD_MONITOR_NAME_STRING 20 /* offsets 20..(20+mnl-1) inclusive */ + +#define DRM_ELD_CEA_SAD(mnl, sad) (20 + (mnl) + 3 * (sad)) + +/** + * drm_eld_mnl - Get ELD monitor name length in bytes. + * @eld: pointer to an eld memory structure with mnl set + */ +static inline int drm_eld_mnl(const u8 *eld) +{ + return (eld[DRM_ELD_CEA_EDID_VER_MNL] & DRM_ELD_MNL_MASK) >> DRM_ELD_MNL_SHIFT; +} + +int drm_eld_sad_get(const u8 *eld, int sad_index, struct cea_sad *cta_sad); +int drm_eld_sad_set(u8 *eld, int sad_index, const struct cea_sad *cta_sad); + +/** + * drm_eld_sad - Get ELD SAD structures. + * @eld: pointer to an eld memory structure with sad_count set + */ +static inline const u8 *drm_eld_sad(const u8 *eld) +{ + unsigned int ver, mnl; + + ver = (eld[DRM_ELD_VER] & DRM_ELD_VER_MASK) >> DRM_ELD_VER_SHIFT; + if (ver != 2 && ver != 31) + return NULL; + + mnl = drm_eld_mnl(eld); + if (mnl > 16) + return NULL; + + return eld + DRM_ELD_CEA_SAD(mnl, 0); +} + +/** + * drm_eld_sad_count - Get ELD SAD count. + * @eld: pointer to an eld memory structure with sad_count set + */ +static inline int drm_eld_sad_count(const u8 *eld) +{ + return (eld[DRM_ELD_SAD_COUNT_CONN_TYPE] & DRM_ELD_SAD_COUNT_MASK) >> + DRM_ELD_SAD_COUNT_SHIFT; +} + +/** + * drm_eld_calc_baseline_block_size - Calculate baseline block size in bytes + * @eld: pointer to an eld memory structure with mnl and sad_count set + * + * This is a helper for determining the payload size of the baseline block, in + * bytes, for e.g. setting the Baseline_ELD_Len field in the ELD header block. + */ +static inline int drm_eld_calc_baseline_block_size(const u8 *eld) +{ + return DRM_ELD_MONITOR_NAME_STRING - DRM_ELD_HEADER_BLOCK_SIZE + + drm_eld_mnl(eld) + drm_eld_sad_count(eld) * 3; +} + +/** + * drm_eld_size - Get ELD size in bytes + * @eld: pointer to a complete eld memory structure + * + * The returned value does not include the vendor block. It's vendor specific, + * and comprises of the remaining bytes in the ELD memory buffer after + * drm_eld_size() bytes of header and baseline block. + * + * The returned value is guaranteed to be a multiple of 4. + */ +static inline int drm_eld_size(const u8 *eld) +{ + return DRM_ELD_HEADER_BLOCK_SIZE + eld[DRM_ELD_BASELINE_ELD_LEN] * 4; +} + +/** + * drm_eld_get_spk_alloc - Get speaker allocation + * @eld: pointer to an ELD memory structure + * + * The returned value is the speakers mask. User has to use %DRM_ELD_SPEAKER + * field definitions to identify speakers. + */ +static inline u8 drm_eld_get_spk_alloc(const u8 *eld) +{ + return eld[DRM_ELD_SPEAKER] & DRM_ELD_SPEAKER_MASK; +} + +/** + * drm_eld_get_conn_type - Get device type hdmi/dp connected + * @eld: pointer to an ELD memory structure + * + * The caller need to use %DRM_ELD_CONN_TYPE_HDMI or %DRM_ELD_CONN_TYPE_DP to + * identify the display type connected. + */ +static inline u8 drm_eld_get_conn_type(const u8 *eld) +{ + return eld[DRM_ELD_SAD_COUNT_CONN_TYPE] & DRM_ELD_CONN_TYPE_MASK; +} + +#endif /* __DRM_ELD_H__ */ -- cgit v1.3.1