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/rtc/rtc-msm6242.c | 228 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 228 insertions(+) create mode 100644 drivers/rtc/rtc-msm6242.c (limited to 'drivers/rtc/rtc-msm6242.c') diff --git a/drivers/rtc/rtc-msm6242.c b/drivers/rtc/rtc-msm6242.c new file mode 100644 index 000000000..80e364baa --- /dev/null +++ b/drivers/rtc/rtc-msm6242.c @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Oki MSM6242 RTC Driver + * + * Copyright 2009 Geert Uytterhoeven + * + * Based on the A2000 TOD code in arch/m68k/amiga/config.c + * Copyright (C) 1993 Hamish Macdonald + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include + + +enum { + MSM6242_SECOND1 = 0x0, /* 1-second digit register */ + MSM6242_SECOND10 = 0x1, /* 10-second digit register */ + MSM6242_MINUTE1 = 0x2, /* 1-minute digit register */ + MSM6242_MINUTE10 = 0x3, /* 10-minute digit register */ + MSM6242_HOUR1 = 0x4, /* 1-hour digit register */ + MSM6242_HOUR10 = 0x5, /* PM/AM, 10-hour digit register */ + MSM6242_DAY1 = 0x6, /* 1-day digit register */ + MSM6242_DAY10 = 0x7, /* 10-day digit register */ + MSM6242_MONTH1 = 0x8, /* 1-month digit register */ + MSM6242_MONTH10 = 0x9, /* 10-month digit register */ + MSM6242_YEAR1 = 0xa, /* 1-year digit register */ + MSM6242_YEAR10 = 0xb, /* 10-year digit register */ + MSM6242_WEEK = 0xc, /* Week register */ + MSM6242_CD = 0xd, /* Control Register D */ + MSM6242_CE = 0xe, /* Control Register E */ + MSM6242_CF = 0xf, /* Control Register F */ +}; + +#define MSM6242_HOUR10_AM (0 << 2) +#define MSM6242_HOUR10_PM (1 << 2) +#define MSM6242_HOUR10_HR_MASK (3 << 0) + +#define MSM6242_WEEK_SUNDAY 0 +#define MSM6242_WEEK_MONDAY 1 +#define MSM6242_WEEK_TUESDAY 2 +#define MSM6242_WEEK_WEDNESDAY 3 +#define MSM6242_WEEK_THURSDAY 4 +#define MSM6242_WEEK_FRIDAY 5 +#define MSM6242_WEEK_SATURDAY 6 + +#define MSM6242_CD_30_S_ADJ (1 << 3) /* 30-second adjustment */ +#define MSM6242_CD_IRQ_FLAG (1 << 2) +#define MSM6242_CD_BUSY (1 << 1) +#define MSM6242_CD_HOLD (1 << 0) + +#define MSM6242_CE_T_MASK (3 << 2) +#define MSM6242_CE_T_64HZ (0 << 2) /* period 1/64 second */ +#define MSM6242_CE_T_1HZ (1 << 2) /* period 1 second */ +#define MSM6242_CE_T_1MINUTE (2 << 2) /* period 1 minute */ +#define MSM6242_CE_T_1HOUR (3 << 2) /* period 1 hour */ + +#define MSM6242_CE_ITRPT_STND (1 << 1) +#define MSM6242_CE_MASK (1 << 0) /* STD.P output control */ + +#define MSM6242_CF_TEST (1 << 3) +#define MSM6242_CF_12H (0 << 2) +#define MSM6242_CF_24H (1 << 2) +#define MSM6242_CF_STOP (1 << 1) +#define MSM6242_CF_REST (1 << 0) /* reset */ + + +struct msm6242_priv { + u32 __iomem *regs; + struct rtc_device *rtc; +}; + +static inline unsigned int msm6242_read(struct msm6242_priv *priv, + unsigned int reg) +{ + return __raw_readl(&priv->regs[reg]) & 0xf; +} + +static inline void msm6242_write(struct msm6242_priv *priv, unsigned int val, + unsigned int reg) +{ + __raw_writel(val, &priv->regs[reg]); +} + +static void msm6242_lock(struct msm6242_priv *priv) +{ + int cnt = 5; + + msm6242_write(priv, MSM6242_CD_HOLD|MSM6242_CD_IRQ_FLAG, MSM6242_CD); + + while ((msm6242_read(priv, MSM6242_CD) & MSM6242_CD_BUSY) && cnt) { + msm6242_write(priv, MSM6242_CD_IRQ_FLAG, MSM6242_CD); + udelay(70); + msm6242_write(priv, MSM6242_CD_HOLD|MSM6242_CD_IRQ_FLAG, MSM6242_CD); + cnt--; + } + + if (!cnt) + pr_warn("timed out waiting for RTC (0x%x)\n", + msm6242_read(priv, MSM6242_CD)); +} + +static void msm6242_unlock(struct msm6242_priv *priv) +{ + msm6242_write(priv, MSM6242_CD_IRQ_FLAG, MSM6242_CD); +} + +static int msm6242_read_time(struct device *dev, struct rtc_time *tm) +{ + struct msm6242_priv *priv = dev_get_drvdata(dev); + + msm6242_lock(priv); + + tm->tm_sec = msm6242_read(priv, MSM6242_SECOND10) * 10 + + msm6242_read(priv, MSM6242_SECOND1); + tm->tm_min = msm6242_read(priv, MSM6242_MINUTE10) * 10 + + msm6242_read(priv, MSM6242_MINUTE1); + tm->tm_hour = (msm6242_read(priv, MSM6242_HOUR10) & + MSM6242_HOUR10_HR_MASK) * 10 + + msm6242_read(priv, MSM6242_HOUR1); + tm->tm_mday = msm6242_read(priv, MSM6242_DAY10) * 10 + + msm6242_read(priv, MSM6242_DAY1); + tm->tm_wday = msm6242_read(priv, MSM6242_WEEK); + tm->tm_mon = msm6242_read(priv, MSM6242_MONTH10) * 10 + + msm6242_read(priv, MSM6242_MONTH1) - 1; + tm->tm_year = msm6242_read(priv, MSM6242_YEAR10) * 10 + + msm6242_read(priv, MSM6242_YEAR1); + if (tm->tm_year <= 69) + tm->tm_year += 100; + + if (!(msm6242_read(priv, MSM6242_CF) & MSM6242_CF_24H)) { + unsigned int pm = msm6242_read(priv, MSM6242_HOUR10) & + MSM6242_HOUR10_PM; + if (!pm && tm->tm_hour == 12) + tm->tm_hour = 0; + else if (pm && tm->tm_hour != 12) + tm->tm_hour += 12; + } + + msm6242_unlock(priv); + + return 0; +} + +static int msm6242_set_time(struct device *dev, struct rtc_time *tm) +{ + struct msm6242_priv *priv = dev_get_drvdata(dev); + + msm6242_lock(priv); + + msm6242_write(priv, tm->tm_sec / 10, MSM6242_SECOND10); + msm6242_write(priv, tm->tm_sec % 10, MSM6242_SECOND1); + msm6242_write(priv, tm->tm_min / 10, MSM6242_MINUTE10); + msm6242_write(priv, tm->tm_min % 10, MSM6242_MINUTE1); + if (msm6242_read(priv, MSM6242_CF) & MSM6242_CF_24H) + msm6242_write(priv, tm->tm_hour / 10, MSM6242_HOUR10); + else if (tm->tm_hour >= 12) + msm6242_write(priv, MSM6242_HOUR10_PM + (tm->tm_hour - 12) / 10, + MSM6242_HOUR10); + else + msm6242_write(priv, tm->tm_hour / 10, MSM6242_HOUR10); + msm6242_write(priv, tm->tm_hour % 10, MSM6242_HOUR1); + msm6242_write(priv, tm->tm_mday / 10, MSM6242_DAY10); + msm6242_write(priv, tm->tm_mday % 10, MSM6242_DAY1); + if (tm->tm_wday != -1) + msm6242_write(priv, tm->tm_wday, MSM6242_WEEK); + msm6242_write(priv, (tm->tm_mon + 1) / 10, MSM6242_MONTH10); + msm6242_write(priv, (tm->tm_mon + 1) % 10, MSM6242_MONTH1); + if (tm->tm_year >= 100) + tm->tm_year -= 100; + msm6242_write(priv, tm->tm_year / 10, MSM6242_YEAR10); + msm6242_write(priv, tm->tm_year % 10, MSM6242_YEAR1); + + msm6242_unlock(priv); + return 0; +} + +static const struct rtc_class_ops msm6242_rtc_ops = { + .read_time = msm6242_read_time, + .set_time = msm6242_set_time, +}; + +static int __init msm6242_rtc_probe(struct platform_device *pdev) +{ + struct resource *res; + struct msm6242_priv *priv; + struct rtc_device *rtc; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + if (!priv->regs) + return -ENOMEM; + platform_set_drvdata(pdev, priv); + + rtc = devm_rtc_device_register(&pdev->dev, "rtc-msm6242", + &msm6242_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + priv->rtc = rtc; + return 0; +} + +static struct platform_driver msm6242_rtc_driver = { + .driver = { + .name = "rtc-msm6242", + }, +}; + +module_platform_driver_probe(msm6242_rtc_driver, msm6242_rtc_probe); + +MODULE_AUTHOR("Geert Uytterhoeven "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Oki MSM6242 RTC driver"); +MODULE_ALIAS("platform:rtc-msm6242"); -- cgit v1.3.1