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/base/regmap/regmap-fsi.c | 231 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 231 insertions(+) create mode 100644 drivers/base/regmap/regmap-fsi.c (limited to 'drivers/base/regmap/regmap-fsi.c') diff --git a/drivers/base/regmap/regmap-fsi.c b/drivers/base/regmap/regmap-fsi.c new file mode 100644 index 000000000..3d2f3cb31 --- /dev/null +++ b/drivers/base/regmap/regmap-fsi.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Register map access API - FSI support +// +// Copyright 2022 IBM Corp +// +// Author: Eddie James + +#include +#include +#include + +#include "internal.h" + +static int regmap_fsi32_reg_read(void *context, unsigned int reg, unsigned int *val) +{ + u32 v; + int ret; + + ret = fsi_slave_read(context, reg, &v, sizeof(v)); + if (ret) + return ret; + + *val = v; + return 0; +} + +static int regmap_fsi32_reg_write(void *context, unsigned int reg, unsigned int val) +{ + u32 v = val; + + return fsi_slave_write(context, reg, &v, sizeof(v)); +} + +static const struct regmap_bus regmap_fsi32 = { + .reg_write = regmap_fsi32_reg_write, + .reg_read = regmap_fsi32_reg_read, +}; + +static int regmap_fsi32le_reg_read(void *context, unsigned int reg, unsigned int *val) +{ + __be32 v; + int ret; + + ret = fsi_slave_read(context, reg, &v, sizeof(v)); + if (ret) + return ret; + + *val = be32_to_cpu(v); + return 0; +} + +static int regmap_fsi32le_reg_write(void *context, unsigned int reg, unsigned int val) +{ + __be32 v = cpu_to_be32(val); + + return fsi_slave_write(context, reg, &v, sizeof(v)); +} + +static const struct regmap_bus regmap_fsi32le = { + .reg_write = regmap_fsi32le_reg_write, + .reg_read = regmap_fsi32le_reg_read, +}; + +static int regmap_fsi16_reg_read(void *context, unsigned int reg, unsigned int *val) +{ + u16 v; + int ret; + + ret = fsi_slave_read(context, reg, &v, sizeof(v)); + if (ret) + return ret; + + *val = v; + return 0; +} + +static int regmap_fsi16_reg_write(void *context, unsigned int reg, unsigned int val) +{ + u16 v; + + if (val > 0xffff) + return -EINVAL; + + v = val; + return fsi_slave_write(context, reg, &v, sizeof(v)); +} + +static const struct regmap_bus regmap_fsi16 = { + .reg_write = regmap_fsi16_reg_write, + .reg_read = regmap_fsi16_reg_read, +}; + +static int regmap_fsi16le_reg_read(void *context, unsigned int reg, unsigned int *val) +{ + __be16 v; + int ret; + + ret = fsi_slave_read(context, reg, &v, sizeof(v)); + if (ret) + return ret; + + *val = be16_to_cpu(v); + return 0; +} + +static int regmap_fsi16le_reg_write(void *context, unsigned int reg, unsigned int val) +{ + __be16 v; + + if (val > 0xffff) + return -EINVAL; + + v = cpu_to_be16(val); + return fsi_slave_write(context, reg, &v, sizeof(v)); +} + +static const struct regmap_bus regmap_fsi16le = { + .reg_write = regmap_fsi16le_reg_write, + .reg_read = regmap_fsi16le_reg_read, +}; + +static int regmap_fsi8_reg_read(void *context, unsigned int reg, unsigned int *val) +{ + u8 v; + int ret; + + ret = fsi_slave_read(context, reg, &v, sizeof(v)); + if (ret) + return ret; + + *val = v; + return 0; +} + +static int regmap_fsi8_reg_write(void *context, unsigned int reg, unsigned int val) +{ + u8 v; + + if (val > 0xff) + return -EINVAL; + + v = val; + return fsi_slave_write(context, reg, &v, sizeof(v)); +} + +static const struct regmap_bus regmap_fsi8 = { + .reg_write = regmap_fsi8_reg_write, + .reg_read = regmap_fsi8_reg_read, +}; + +static const struct regmap_bus *regmap_get_fsi_bus(struct fsi_device *fsi_dev, + const struct regmap_config *config) +{ + const struct regmap_bus *bus = NULL; + + if (config->reg_bits == 8 || config->reg_bits == 16 || config->reg_bits == 32) { + switch (config->val_bits) { + case 8: + bus = ®map_fsi8; + break; + case 16: + switch (regmap_get_val_endian(&fsi_dev->dev, NULL, config)) { + case REGMAP_ENDIAN_LITTLE: +#ifdef __LITTLE_ENDIAN + case REGMAP_ENDIAN_NATIVE: +#endif + bus = ®map_fsi16le; + break; + case REGMAP_ENDIAN_DEFAULT: + case REGMAP_ENDIAN_BIG: +#ifdef __BIG_ENDIAN + case REGMAP_ENDIAN_NATIVE: +#endif + bus = ®map_fsi16; + break; + default: + break; + } + break; + case 32: + switch (regmap_get_val_endian(&fsi_dev->dev, NULL, config)) { + case REGMAP_ENDIAN_LITTLE: +#ifdef __LITTLE_ENDIAN + case REGMAP_ENDIAN_NATIVE: +#endif + bus = ®map_fsi32le; + break; + case REGMAP_ENDIAN_DEFAULT: + case REGMAP_ENDIAN_BIG: +#ifdef __BIG_ENDIAN + case REGMAP_ENDIAN_NATIVE: +#endif + bus = ®map_fsi32; + break; + default: + break; + } + break; + } + } + + return bus ?: ERR_PTR(-EOPNOTSUPP); +} + +struct regmap *__regmap_init_fsi(struct fsi_device *fsi_dev, const struct regmap_config *config, + struct lock_class_key *lock_key, const char *lock_name) +{ + const struct regmap_bus *bus = regmap_get_fsi_bus(fsi_dev, config); + + if (IS_ERR(bus)) + return ERR_CAST(bus); + + return __regmap_init(&fsi_dev->dev, bus, fsi_dev->slave, config, lock_key, lock_name); +} +EXPORT_SYMBOL_GPL(__regmap_init_fsi); + +struct regmap *__devm_regmap_init_fsi(struct fsi_device *fsi_dev, + const struct regmap_config *config, + struct lock_class_key *lock_key, const char *lock_name) +{ + const struct regmap_bus *bus = regmap_get_fsi_bus(fsi_dev, config); + + if (IS_ERR(bus)) + return ERR_CAST(bus); + + return __devm_regmap_init(&fsi_dev->dev, bus, fsi_dev->slave, config, lock_key, lock_name); +} +EXPORT_SYMBOL_GPL(__devm_regmap_init_fsi); + +MODULE_LICENSE("GPL"); -- cgit v1.3.1