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/reset/reset-a10sr.c | 128 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 drivers/reset/reset-a10sr.c (limited to 'drivers/reset/reset-a10sr.c') diff --git a/drivers/reset/reset-a10sr.c b/drivers/reset/reset-a10sr.c new file mode 100644 index 000000000..99b3bc838 --- /dev/null +++ b/drivers/reset/reset-a10sr.c @@ -0,0 +1,128 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright Intel Corporation (C) 2017. All Rights Reserved + * + * Reset driver for Altera Arria10 MAX5 System Resource Chip + * + * Adapted from reset-socfpga.c + */ + +#include +#include +#include +#include +#include +#include + +#include + +struct a10sr_reset { + struct reset_controller_dev rcdev; + struct regmap *regmap; +}; + +static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc) +{ + return container_of(rc, struct a10sr_reset, rcdev); +} + +static inline int a10sr_reset_shift(unsigned long id) +{ + switch (id) { + case A10SR_RESET_ENET_HPS: + return 1; + case A10SR_RESET_PCIE: + case A10SR_RESET_FILE: + case A10SR_RESET_BQSPI: + case A10SR_RESET_USB: + return id + 11; + default: + return -EINVAL; + } +} + +static int a10sr_reset_update(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct a10sr_reset *a10r = to_a10sr_rst(rcdev); + int offset = a10sr_reset_shift(id); + u8 mask = ALTR_A10SR_REG_BIT_MASK(offset); + int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset); + + return regmap_update_bits(a10r->regmap, index, mask, assert ? 0 : mask); +} + +static int a10sr_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return a10sr_reset_update(rcdev, id, true); +} + +static int a10sr_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return a10sr_reset_update(rcdev, id, false); +} + +static int a10sr_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + int ret; + struct a10sr_reset *a10r = to_a10sr_rst(rcdev); + int offset = a10sr_reset_shift(id); + u8 mask = ALTR_A10SR_REG_BIT_MASK(offset); + int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset); + unsigned int value; + + ret = regmap_read(a10r->regmap, index, &value); + if (ret < 0) + return ret; + + return !!(value & mask); +} + +static const struct reset_control_ops a10sr_reset_ops = { + .assert = a10sr_reset_assert, + .deassert = a10sr_reset_deassert, + .status = a10sr_reset_status, +}; + +static int a10sr_reset_probe(struct platform_device *pdev) +{ + struct altr_a10sr *a10sr = dev_get_drvdata(pdev->dev.parent); + struct a10sr_reset *a10r; + + a10r = devm_kzalloc(&pdev->dev, sizeof(struct a10sr_reset), + GFP_KERNEL); + if (!a10r) + return -ENOMEM; + + a10r->rcdev.owner = THIS_MODULE; + a10r->rcdev.nr_resets = A10SR_RESET_NUM; + a10r->rcdev.ops = &a10sr_reset_ops; + a10r->rcdev.of_node = pdev->dev.of_node; + a10r->regmap = a10sr->regmap; + + platform_set_drvdata(pdev, a10r); + + return devm_reset_controller_register(&pdev->dev, &a10r->rcdev); +} + +static const struct of_device_id a10sr_reset_of_match[] = { + { .compatible = "altr,a10sr-reset" }, + { }, +}; +MODULE_DEVICE_TABLE(of, a10sr_reset_of_match); + +static struct platform_driver a10sr_reset_driver = { + .probe = a10sr_reset_probe, + .driver = { + .name = "altr_a10sr_reset", + .of_match_table = a10sr_reset_of_match, + }, +}; +module_platform_driver(a10sr_reset_driver); + +MODULE_AUTHOR("Thor Thayer "); +MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1