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/clocksource/timer-rda.c | 202 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 drivers/clocksource/timer-rda.c (limited to 'drivers/clocksource/timer-rda.c') diff --git a/drivers/clocksource/timer-rda.c b/drivers/clocksource/timer-rda.c new file mode 100644 index 000000000..0be8e0597 --- /dev/null +++ b/drivers/clocksource/timer-rda.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * RDA8810PL SoC timer driver + * + * Copyright RDA Microelectronics Company Limited + * Copyright (c) 2017 Andreas Färber + * Copyright (c) 2018 Manivannan Sadhasivam + * + * RDA8810PL has two independent timers: OSTIMER (56 bit) and HWTIMER (64 bit). + * Each timer provides optional interrupt support. In this driver, OSTIMER is + * used for clockevents and HWTIMER is used for clocksource. + */ + +#include +#include +#include + +#include "timer-of.h" + +#define RDA_OSTIMER_LOADVAL_L 0x000 +#define RDA_OSTIMER_CTRL 0x004 +#define RDA_HWTIMER_LOCKVAL_L 0x024 +#define RDA_HWTIMER_LOCKVAL_H 0x028 +#define RDA_TIMER_IRQ_MASK_SET 0x02c +#define RDA_TIMER_IRQ_MASK_CLR 0x030 +#define RDA_TIMER_IRQ_CLR 0x034 + +#define RDA_OSTIMER_CTRL_ENABLE BIT(24) +#define RDA_OSTIMER_CTRL_REPEAT BIT(28) +#define RDA_OSTIMER_CTRL_LOAD BIT(30) + +#define RDA_TIMER_IRQ_MASK_OSTIMER BIT(0) + +#define RDA_TIMER_IRQ_CLR_OSTIMER BIT(0) + +static int rda_ostimer_start(void __iomem *base, bool periodic, u64 cycles) +{ + u32 ctrl, load_l; + + load_l = (u32)cycles; + ctrl = ((cycles >> 32) & 0xffffff); + ctrl |= RDA_OSTIMER_CTRL_LOAD | RDA_OSTIMER_CTRL_ENABLE; + if (periodic) + ctrl |= RDA_OSTIMER_CTRL_REPEAT; + + /* Enable ostimer interrupt first */ + writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER, + base + RDA_TIMER_IRQ_MASK_SET); + + /* Write low 32 bits first, high 24 bits are with ctrl */ + writel_relaxed(load_l, base + RDA_OSTIMER_LOADVAL_L); + writel_relaxed(ctrl, base + RDA_OSTIMER_CTRL); + + return 0; +} + +static int rda_ostimer_stop(void __iomem *base) +{ + /* Disable ostimer interrupt first */ + writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER, + base + RDA_TIMER_IRQ_MASK_CLR); + + writel_relaxed(0, base + RDA_OSTIMER_CTRL); + + return 0; +} + +static int rda_ostimer_set_state_shutdown(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + + rda_ostimer_stop(timer_of_base(to)); + + return 0; +} + +static int rda_ostimer_set_state_oneshot(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + + rda_ostimer_stop(timer_of_base(to)); + + return 0; +} + +static int rda_ostimer_set_state_periodic(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + unsigned long cycles_per_jiffy; + + rda_ostimer_stop(timer_of_base(to)); + + cycles_per_jiffy = ((unsigned long long)NSEC_PER_SEC / HZ * + evt->mult) >> evt->shift; + rda_ostimer_start(timer_of_base(to), true, cycles_per_jiffy); + + return 0; +} + +static int rda_ostimer_tick_resume(struct clock_event_device *evt) +{ + return 0; +} + +static int rda_ostimer_set_next_event(unsigned long evt, + struct clock_event_device *ev) +{ + struct timer_of *to = to_timer_of(ev); + + rda_ostimer_start(timer_of_base(to), false, evt); + + return 0; +} + +static irqreturn_t rda_ostimer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + struct timer_of *to = to_timer_of(evt); + + /* clear timer int */ + writel_relaxed(RDA_TIMER_IRQ_CLR_OSTIMER, + timer_of_base(to) + RDA_TIMER_IRQ_CLR); + + if (evt->event_handler) + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct timer_of rda_ostimer_of = { + .flags = TIMER_OF_IRQ | TIMER_OF_BASE, + + .clkevt = { + .name = "rda-ostimer", + .rating = 250, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_DYNIRQ, + .set_state_shutdown = rda_ostimer_set_state_shutdown, + .set_state_oneshot = rda_ostimer_set_state_oneshot, + .set_state_periodic = rda_ostimer_set_state_periodic, + .tick_resume = rda_ostimer_tick_resume, + .set_next_event = rda_ostimer_set_next_event, + }, + + .of_base = { + .name = "rda-timer", + .index = 0, + }, + + .of_irq = { + .name = "ostimer", + .handler = rda_ostimer_interrupt, + .flags = IRQF_TIMER, + }, +}; + +static u64 rda_hwtimer_clocksource_read(void) +{ + void __iomem *base = timer_of_base(&rda_ostimer_of); + u32 lo, hi; + + /* Always read low 32 bits first */ + do { + lo = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_L); + hi = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H); + } while (hi != readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H)); + + return ((u64)hi << 32) | lo; +} + +static u64 rda_hwtimer_read(struct clocksource *cs) +{ + return rda_hwtimer_clocksource_read(); +} + +static struct clocksource rda_hwtimer_clocksource = { + .name = "rda-timer", + .rating = 400, + .read = rda_hwtimer_read, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init rda_timer_init(struct device_node *np) +{ + unsigned long rate = 2000000; + int ret; + + ret = timer_of_init(np, &rda_ostimer_of); + if (ret) + return ret; + + clocksource_register_hz(&rda_hwtimer_clocksource, rate); + sched_clock_register(rda_hwtimer_clocksource_read, 64, rate); + + clockevents_config_and_register(&rda_ostimer_of.clkevt, rate, + 0x2, UINT_MAX); + + return 0; +} + +TIMER_OF_DECLARE(rda8810pl, "rda,8810pl-timer", rda_timer_init); -- cgit v1.3.1