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 --- drivers/input/input-compat.c | 163 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 163 insertions(+) create mode 100644 drivers/input/input-compat.c (limited to 'drivers/input/input-compat.c') diff --git a/drivers/input/input-compat.c b/drivers/input/input-compat.c new file mode 100644 index 000000000..a5043193e --- /dev/null +++ b/drivers/input/input-compat.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 32bit compatibility wrappers for the input subsystem. + * + * Very heavily based on evdev.c - Copyright (c) 1999-2002 Vojtech Pavlik + */ + +#include +#include +#include +#include "input-compat.h" + +#ifdef CONFIG_COMPAT + +int input_event_from_user(const char __user *buffer, + struct input_event *event) +{ + if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) { + struct input_event_compat compat_event; + + if (copy_from_user(&compat_event, buffer, + sizeof(struct input_event_compat))) + return -EFAULT; + + event->input_event_sec = compat_event.sec; + event->input_event_usec = compat_event.usec; + event->type = compat_event.type; + event->code = compat_event.code; + event->value = compat_event.value; + + } else { + if (copy_from_user(event, buffer, sizeof(struct input_event))) + return -EFAULT; + } + + return 0; +} + +int input_event_to_user(char __user *buffer, + const struct input_event *event) +{ + if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) { + struct input_event_compat compat_event; + + compat_event.sec = event->input_event_sec; + compat_event.usec = event->input_event_usec; + compat_event.type = event->type; + compat_event.code = event->code; + compat_event.value = event->value; + + if (copy_to_user(buffer, &compat_event, + sizeof(struct input_event_compat))) + return -EFAULT; + + } else { + if (copy_to_user(buffer, event, sizeof(struct input_event))) + return -EFAULT; + } + + return 0; +} + +int input_ff_effect_from_user(const char __user *buffer, size_t size, + struct ff_effect *effect) +{ + if (in_compat_syscall()) { + struct ff_effect_compat *compat_effect; + + if (size != sizeof(struct ff_effect_compat)) + return -EINVAL; + + /* + * It so happens that the pointer which needs to be changed + * is the last field in the structure, so we can retrieve the + * whole thing and replace just the pointer. + */ + compat_effect = (struct ff_effect_compat *)effect; + + if (copy_from_user(compat_effect, buffer, + sizeof(struct ff_effect_compat))) + return -EFAULT; + + if (compat_effect->type == FF_PERIODIC && + compat_effect->u.periodic.waveform == FF_CUSTOM) + effect->u.periodic.custom_data = + compat_ptr(compat_effect->u.periodic.custom_data); + } else { + if (size != sizeof(struct ff_effect)) + return -EINVAL; + + if (copy_from_user(effect, buffer, sizeof(struct ff_effect))) + return -EFAULT; + } + + return 0; +} + +int input_bits_to_string(char *buf, int buf_size, unsigned long bits, + bool skip_empty) +{ + int len = 0; + + if (in_compat_syscall()) { + u32 dword = bits >> 32; + if (dword || !skip_empty) + len += snprintf(buf, buf_size, "%x ", dword); + + dword = bits & 0xffffffffUL; + if (dword || !skip_empty || len) + len += snprintf(buf + len, max(buf_size - len, 0), + "%x", dword); + } else { + if (bits || !skip_empty) + len += snprintf(buf, buf_size, "%lx", bits); + } + + return len; +} + +#else + +int input_event_from_user(const char __user *buffer, + struct input_event *event) +{ + if (copy_from_user(event, buffer, sizeof(struct input_event))) + return -EFAULT; + + return 0; +} + +int input_event_to_user(char __user *buffer, + const struct input_event *event) +{ + if (copy_to_user(buffer, event, sizeof(struct input_event))) + return -EFAULT; + + return 0; +} + +int input_ff_effect_from_user(const char __user *buffer, size_t size, + struct ff_effect *effect) +{ + if (size != sizeof(struct ff_effect)) + return -EINVAL; + + if (copy_from_user(effect, buffer, sizeof(struct ff_effect))) + return -EFAULT; + + return 0; +} + +int input_bits_to_string(char *buf, int buf_size, unsigned long bits, + bool skip_empty) +{ + return bits || !skip_empty ? + snprintf(buf, buf_size, "%lx", bits) : 0; +} + +#endif /* CONFIG_COMPAT */ + +EXPORT_SYMBOL_GPL(input_event_from_user); +EXPORT_SYMBOL_GPL(input_event_to_user); +EXPORT_SYMBOL_GPL(input_ff_effect_from_user); -- cgit v1.3.1