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/touchscreen.c | 208 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 drivers/input/touchscreen.c (limited to 'drivers/input/touchscreen.c') diff --git a/drivers/input/touchscreen.c b/drivers/input/touchscreen.c new file mode 100644 index 000000000..d699b24bb --- /dev/null +++ b/drivers/input/touchscreen.c @@ -0,0 +1,208 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Generic helper functions for touchscreens and other two-dimensional + * pointing devices + * + * Copyright (c) 2014 Sebastian Reichel + */ + +#include +#include +#include +#include +#include +#include + +static bool touchscreen_get_prop_u32(struct device *dev, + const char *property, + unsigned int default_value, + unsigned int *value) +{ + u32 val; + int error; + + error = device_property_read_u32(dev, property, &val); + if (error) { + *value = default_value; + return false; + } + + *value = val; + return true; +} + +static void touchscreen_set_params(struct input_dev *dev, + unsigned long axis, + int min, int max, int fuzz) +{ + struct input_absinfo *absinfo; + + if (!test_bit(axis, dev->absbit)) { + dev_warn(&dev->dev, + "Parameters are specified but the axis %lu is not set up\n", + axis); + return; + } + + absinfo = &dev->absinfo[axis]; + absinfo->minimum = min; + absinfo->maximum = max; + absinfo->fuzz = fuzz; +} + +/** + * touchscreen_parse_properties - parse common touchscreen properties + * @input: input device that should be parsed + * @multitouch: specifies whether parsed properties should be applied to + * single-touch or multi-touch axes + * @prop: pointer to a struct touchscreen_properties into which to store + * axis swap and invert info for use with touchscreen_report_x_y(); + * or %NULL + * + * This function parses common properties for touchscreens and sets up the + * input device accordingly. The function keeps previously set up default + * values if no value is specified. + */ +void touchscreen_parse_properties(struct input_dev *input, bool multitouch, + struct touchscreen_properties *prop) +{ + struct device *dev = input->dev.parent; + struct input_absinfo *absinfo; + unsigned int axis, axis_x, axis_y; + unsigned int minimum, maximum, fuzz; + bool data_present; + + input_alloc_absinfo(input); + if (!input->absinfo) + return; + + axis_x = multitouch ? ABS_MT_POSITION_X : ABS_X; + axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y; + + data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x", + input_abs_get_min(input, axis_x), + &minimum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x", + input_abs_get_max(input, + axis_x) + 1, + &maximum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x", + input_abs_get_fuzz(input, axis_x), + &fuzz); + if (data_present) + touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz); + + data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y", + input_abs_get_min(input, axis_y), + &minimum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y", + input_abs_get_max(input, + axis_y) + 1, + &maximum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y", + input_abs_get_fuzz(input, axis_y), + &fuzz); + if (data_present) + touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz); + + axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE; + data_present = touchscreen_get_prop_u32(dev, + "touchscreen-max-pressure", + input_abs_get_max(input, axis), + &maximum); + data_present |= touchscreen_get_prop_u32(dev, + "touchscreen-fuzz-pressure", + input_abs_get_fuzz(input, axis), + &fuzz); + if (data_present) + touchscreen_set_params(input, axis, 0, maximum, fuzz); + + if (!prop) + return; + + prop->max_x = input_abs_get_max(input, axis_x); + prop->max_y = input_abs_get_max(input, axis_y); + + prop->invert_x = + device_property_read_bool(dev, "touchscreen-inverted-x"); + if (prop->invert_x) { + absinfo = &input->absinfo[axis_x]; + absinfo->maximum -= absinfo->minimum; + absinfo->minimum = 0; + } + + prop->invert_y = + device_property_read_bool(dev, "touchscreen-inverted-y"); + if (prop->invert_y) { + absinfo = &input->absinfo[axis_y]; + absinfo->maximum -= absinfo->minimum; + absinfo->minimum = 0; + } + + prop->swap_x_y = + device_property_read_bool(dev, "touchscreen-swapped-x-y"); + if (prop->swap_x_y) + swap(input->absinfo[axis_x], input->absinfo[axis_y]); +} +EXPORT_SYMBOL(touchscreen_parse_properties); + +static void +touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop, + unsigned int *x, unsigned int *y) +{ + if (prop->invert_x) + *x = prop->max_x - *x; + + if (prop->invert_y) + *y = prop->max_y - *y; + + if (prop->swap_x_y) + swap(*x, *y); +} + +/** + * touchscreen_set_mt_pos - Set input_mt_pos coordinates + * @pos: input_mt_pos to set coordinates of + * @prop: pointer to a struct touchscreen_properties + * @x: X coordinate to store in pos + * @y: Y coordinate to store in pos + * + * Adjust the passed in x and y values applying any axis inversion and + * swapping requested in the passed in touchscreen_properties and store + * the result in a struct input_mt_pos. + */ +void touchscreen_set_mt_pos(struct input_mt_pos *pos, + const struct touchscreen_properties *prop, + unsigned int x, unsigned int y) +{ + touchscreen_apply_prop_to_x_y(prop, &x, &y); + pos->x = x; + pos->y = y; +} +EXPORT_SYMBOL(touchscreen_set_mt_pos); + +/** + * touchscreen_report_pos - Report touchscreen coordinates + * @input: input_device to report coordinates for + * @prop: pointer to a struct touchscreen_properties + * @x: X coordinate to report + * @y: Y coordinate to report + * @multitouch: Report coordinates on single-touch or multi-touch axes + * + * Adjust the passed in x and y values applying any axis inversion and + * swapping requested in the passed in touchscreen_properties and then + * report the resulting coordinates on the input_dev's x and y axis. + */ +void touchscreen_report_pos(struct input_dev *input, + const struct touchscreen_properties *prop, + unsigned int x, unsigned int y, + bool multitouch) +{ + touchscreen_apply_prop_to_x_y(prop, &x, &y); + input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x); + input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y); +} +EXPORT_SYMBOL(touchscreen_report_pos); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Helper functions for touchscreens and other devices"); -- cgit v1.3.1