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/mfd/altera-sysmgr.c | 203 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 drivers/mfd/altera-sysmgr.c (limited to 'drivers/mfd/altera-sysmgr.c') diff --git a/drivers/mfd/altera-sysmgr.c b/drivers/mfd/altera-sysmgr.c new file mode 100644 index 000000000..90c6902d5 --- /dev/null +++ b/drivers/mfd/altera-sysmgr.c @@ -0,0 +1,203 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018-2019, Intel Corporation. + * Copyright (C) 2012 Freescale Semiconductor, Inc. + * Copyright (C) 2012 Linaro Ltd. + * + * Based on syscon driver. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * struct altr_sysmgr - Altera SOCFPGA System Manager + * @regmap: the regmap used for System Manager accesses. + */ +struct altr_sysmgr { + struct regmap *regmap; +}; + +static struct platform_driver altr_sysmgr_driver; + +/** + * s10_protected_reg_write + * Write to a protected SMC register. + * @base: Base address of System Manager + * @reg: Address offset of register + * @val: Value to write + * Return: INTEL_SIP_SMC_STATUS_OK (0) on success + * INTEL_SIP_SMC_REG_ERROR on error + * INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported + */ +static int s10_protected_reg_write(void *base, + unsigned int reg, unsigned int val) +{ + struct arm_smccc_res result; + unsigned long sysmgr_base = (unsigned long)base; + + arm_smccc_smc(INTEL_SIP_SMC_REG_WRITE, sysmgr_base + reg, + val, 0, 0, 0, 0, 0, &result); + + return (int)result.a0; +} + +/** + * s10_protected_reg_read + * Read the status of a protected SMC register + * @base: Base address of System Manager. + * @reg: Address of register + * @val: Value read. + * Return: INTEL_SIP_SMC_STATUS_OK (0) on success + * INTEL_SIP_SMC_REG_ERROR on error + * INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported + */ +static int s10_protected_reg_read(void *base, + unsigned int reg, unsigned int *val) +{ + struct arm_smccc_res result; + unsigned long sysmgr_base = (unsigned long)base; + + arm_smccc_smc(INTEL_SIP_SMC_REG_READ, sysmgr_base + reg, + 0, 0, 0, 0, 0, 0, &result); + + *val = (unsigned int)result.a1; + + return (int)result.a0; +} + +static struct regmap_config altr_sysmgr_regmap_cfg = { + .name = "altr_sysmgr", + .reg_bits = 32, + .reg_stride = 4, + .val_bits = 32, + .fast_io = true, + .use_single_read = true, + .use_single_write = true, +}; + +/** + * altr_sysmgr_regmap_lookup_by_phandle + * Find the sysmgr previous configured in probe() and return regmap property. + * Return: regmap if found or error if not found. + * + * @np: Pointer to device's Device Tree node + * @property: Device Tree property name which references the sysmgr + */ +struct regmap *altr_sysmgr_regmap_lookup_by_phandle(struct device_node *np, + const char *property) +{ + struct device *dev; + struct altr_sysmgr *sysmgr; + struct device_node *sysmgr_np; + + if (property) + sysmgr_np = of_parse_phandle(np, property, 0); + else + sysmgr_np = np; + + if (!sysmgr_np) + return ERR_PTR(-ENODEV); + + dev = driver_find_device_by_of_node(&altr_sysmgr_driver.driver, + (void *)sysmgr_np); + if (property) + of_node_put(sysmgr_np); + + if (!dev) + return ERR_PTR(-EPROBE_DEFER); + + sysmgr = dev_get_drvdata(dev); + + put_device(dev); + + return sysmgr->regmap; +} +EXPORT_SYMBOL_GPL(altr_sysmgr_regmap_lookup_by_phandle); + +static int sysmgr_probe(struct platform_device *pdev) +{ + struct altr_sysmgr *sysmgr; + struct regmap *regmap; + struct resource *res; + struct regmap_config sysmgr_config = altr_sysmgr_regmap_cfg; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + void __iomem *base; + + sysmgr = devm_kzalloc(dev, sizeof(*sysmgr), GFP_KERNEL); + if (!sysmgr) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENOENT; + + sysmgr_config.max_register = resource_size(res) - + sysmgr_config.reg_stride; + if (of_device_is_compatible(np, "altr,sys-mgr-s10")) { + sysmgr_config.reg_read = s10_protected_reg_read; + sysmgr_config.reg_write = s10_protected_reg_write; + + /* Need physical address for SMCC call */ + regmap = devm_regmap_init(dev, NULL, + (void *)(uintptr_t)res->start, + &sysmgr_config); + } else { + base = devm_ioremap(dev, res->start, resource_size(res)); + if (!base) + return -ENOMEM; + + sysmgr_config.max_register = resource_size(res) - 4; + regmap = devm_regmap_init_mmio(dev, base, &sysmgr_config); + } + + if (IS_ERR(regmap)) { + pr_err("regmap init failed\n"); + return PTR_ERR(regmap); + } + + sysmgr->regmap = regmap; + + platform_set_drvdata(pdev, sysmgr); + + return 0; +} + +static const struct of_device_id altr_sysmgr_of_match[] = { + { .compatible = "altr,sys-mgr" }, + { .compatible = "altr,sys-mgr-s10" }, + {}, +}; +MODULE_DEVICE_TABLE(of, altr_sysmgr_of_match); + +static struct platform_driver altr_sysmgr_driver = { + .probe = sysmgr_probe, + .driver = { + .name = "altr,system_manager", + .of_match_table = altr_sysmgr_of_match, + }, +}; + +static int __init altr_sysmgr_init(void) +{ + return platform_driver_register(&altr_sysmgr_driver); +} +core_initcall(altr_sysmgr_init); + +static void __exit altr_sysmgr_exit(void) +{ + platform_driver_unregister(&altr_sysmgr_driver); +} +module_exit(altr_sysmgr_exit); + +MODULE_AUTHOR("Thor Thayer <>"); +MODULE_DESCRIPTION("SOCFPGA System Manager driver"); -- cgit v1.3.1