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-qcom.c | 253 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 253 insertions(+) create mode 100644 drivers/clocksource/timer-qcom.c (limited to 'drivers/clocksource/timer-qcom.c') diff --git a/drivers/clocksource/timer-qcom.c b/drivers/clocksource/timer-qcom.c new file mode 100644 index 000000000..ddb1debe6 --- /dev/null +++ b/drivers/clocksource/timer-qcom.c @@ -0,0 +1,253 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (C) 2007 Google, Inc. + * Copyright (c) 2009-2012,2014, The Linux Foundation. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#define TIMER_MATCH_VAL 0x0000 +#define TIMER_COUNT_VAL 0x0004 +#define TIMER_ENABLE 0x0008 +#define TIMER_ENABLE_CLR_ON_MATCH_EN BIT(1) +#define TIMER_ENABLE_EN BIT(0) +#define TIMER_CLEAR 0x000C +#define DGT_CLK_CTL 0x10 +#define DGT_CLK_CTL_DIV_4 0x3 +#define TIMER_STS_GPT0_CLR_PEND BIT(10) + +#define GPT_HZ 32768 + +static void __iomem *event_base; +static void __iomem *sts_base; + +static irqreturn_t msm_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + /* Stop the timer tick */ + if (clockevent_state_oneshot(evt)) { + u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE); + ctrl &= ~TIMER_ENABLE_EN; + writel_relaxed(ctrl, event_base + TIMER_ENABLE); + } + evt->event_handler(evt); + return IRQ_HANDLED; +} + +static int msm_timer_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE); + + ctrl &= ~TIMER_ENABLE_EN; + writel_relaxed(ctrl, event_base + TIMER_ENABLE); + + writel_relaxed(ctrl, event_base + TIMER_CLEAR); + writel_relaxed(cycles, event_base + TIMER_MATCH_VAL); + + if (sts_base) + while (readl_relaxed(sts_base) & TIMER_STS_GPT0_CLR_PEND) + cpu_relax(); + + writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE); + return 0; +} + +static int msm_timer_shutdown(struct clock_event_device *evt) +{ + u32 ctrl; + + ctrl = readl_relaxed(event_base + TIMER_ENABLE); + ctrl &= ~(TIMER_ENABLE_EN | TIMER_ENABLE_CLR_ON_MATCH_EN); + writel_relaxed(ctrl, event_base + TIMER_ENABLE); + return 0; +} + +static struct clock_event_device __percpu *msm_evt; + +static void __iomem *source_base; + +static notrace u64 msm_read_timer_count(struct clocksource *cs) +{ + return readl_relaxed(source_base + TIMER_COUNT_VAL); +} + +static struct clocksource msm_clocksource = { + .name = "dg_timer", + .rating = 300, + .read = msm_read_timer_count, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int msm_timer_irq; +static int msm_timer_has_ppi; + +static int msm_local_timer_starting_cpu(unsigned int cpu) +{ + struct clock_event_device *evt = per_cpu_ptr(msm_evt, cpu); + int err; + + evt->irq = msm_timer_irq; + evt->name = "msm_timer"; + evt->features = CLOCK_EVT_FEAT_ONESHOT; + evt->rating = 200; + evt->set_state_shutdown = msm_timer_shutdown; + evt->set_state_oneshot = msm_timer_shutdown; + evt->tick_resume = msm_timer_shutdown; + evt->set_next_event = msm_timer_set_next_event; + evt->cpumask = cpumask_of(cpu); + + clockevents_config_and_register(evt, GPT_HZ, 4, 0xffffffff); + + if (msm_timer_has_ppi) { + enable_percpu_irq(evt->irq, IRQ_TYPE_EDGE_RISING); + } else { + err = request_irq(evt->irq, msm_timer_interrupt, + IRQF_TIMER | IRQF_NOBALANCING | + IRQF_TRIGGER_RISING, "gp_timer", evt); + if (err) + pr_err("request_irq failed\n"); + } + + return 0; +} + +static int msm_local_timer_dying_cpu(unsigned int cpu) +{ + struct clock_event_device *evt = per_cpu_ptr(msm_evt, cpu); + + disable_percpu_irq(evt->irq); + return 0; +} + +static u64 notrace msm_sched_clock_read(void) +{ + return msm_clocksource.read(&msm_clocksource); +} + +static unsigned long msm_read_current_timer(void) +{ + return msm_clocksource.read(&msm_clocksource); +} + +static struct delay_timer msm_delay_timer = { + .read_current_timer = msm_read_current_timer, +}; + +static int __init msm_timer_init(u32 dgt_hz, int sched_bits, int irq, + bool percpu) +{ + struct clocksource *cs = &msm_clocksource; + int res = 0; + + msm_timer_irq = irq; + msm_timer_has_ppi = percpu; + + msm_evt = alloc_percpu(struct clock_event_device); + if (!msm_evt) { + pr_err("memory allocation failed for clockevents\n"); + goto err; + } + + if (percpu) + res = request_percpu_irq(irq, msm_timer_interrupt, + "gp_timer", msm_evt); + + if (res) { + pr_err("request_percpu_irq failed\n"); + } else { + /* Install and invoke hotplug callbacks */ + res = cpuhp_setup_state(CPUHP_AP_QCOM_TIMER_STARTING, + "clockevents/qcom/timer:starting", + msm_local_timer_starting_cpu, + msm_local_timer_dying_cpu); + if (res) { + free_percpu_irq(irq, msm_evt); + goto err; + } + } + +err: + writel_relaxed(TIMER_ENABLE_EN, source_base + TIMER_ENABLE); + res = clocksource_register_hz(cs, dgt_hz); + if (res) + pr_err("clocksource_register failed\n"); + sched_clock_register(msm_sched_clock_read, sched_bits, dgt_hz); + msm_delay_timer.freq = dgt_hz; + register_current_timer_delay(&msm_delay_timer); + + return res; +} + +static int __init msm_dt_timer_init(struct device_node *np) +{ + u32 freq; + int irq, ret; + struct resource res; + u32 percpu_offset; + void __iomem *base; + void __iomem *cpu0_base; + + base = of_iomap(np, 0); + if (!base) { + pr_err("Failed to map event base\n"); + return -ENXIO; + } + + /* We use GPT0 for the clockevent */ + irq = irq_of_parse_and_map(np, 1); + if (irq <= 0) { + pr_err("Can't get irq\n"); + return -EINVAL; + } + + /* We use CPU0's DGT for the clocksource */ + if (of_property_read_u32(np, "cpu-offset", &percpu_offset)) + percpu_offset = 0; + + ret = of_address_to_resource(np, 0, &res); + if (ret) { + pr_err("Failed to parse DGT resource\n"); + return ret; + } + + cpu0_base = ioremap(res.start + percpu_offset, resource_size(&res)); + if (!cpu0_base) { + pr_err("Failed to map source base\n"); + return -EINVAL; + } + + if (of_property_read_u32(np, "clock-frequency", &freq)) { + iounmap(cpu0_base); + pr_err("Unknown frequency\n"); + return -EINVAL; + } + + event_base = base + 0x4; + sts_base = base + 0x88; + source_base = cpu0_base + 0x24; + freq /= 4; + writel_relaxed(DGT_CLK_CTL_DIV_4, source_base + DGT_CLK_CTL); + + ret = msm_timer_init(freq, 32, irq, !!percpu_offset); + if (ret) + iounmap(cpu0_base); + + return ret; +} +TIMER_OF_DECLARE(kpss_timer, "qcom,kpss-timer", msm_dt_timer_init); +TIMER_OF_DECLARE(scss_timer, "qcom,scss-timer", msm_dt_timer_init); -- cgit v1.3.1