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-imx-tpm.c | 244 ++++++++++++++++++++++++++++++++++++ 1 file changed, 244 insertions(+) create mode 100644 drivers/clocksource/timer-imx-tpm.c (limited to 'drivers/clocksource/timer-imx-tpm.c') diff --git a/drivers/clocksource/timer-imx-tpm.c b/drivers/clocksource/timer-imx-tpm.c new file mode 100644 index 000000000..92c025b70 --- /dev/null +++ b/drivers/clocksource/timer-imx-tpm.c @@ -0,0 +1,244 @@ +// SPDX-License-Identifier: GPL-2.0+ +// +// Copyright 2016 Freescale Semiconductor, Inc. +// Copyright 2017 NXP + +#include +#include +#include +#include +#include +#include + +#include "timer-of.h" + +#define TPM_PARAM 0x4 +#define TPM_PARAM_WIDTH_SHIFT 16 +#define TPM_PARAM_WIDTH_MASK (0xff << 16) +#define TPM_SC 0x10 +#define TPM_SC_CMOD_INC_PER_CNT (0x1 << 3) +#define TPM_SC_CMOD_DIV_DEFAULT 0x3 +#define TPM_SC_CMOD_DIV_MAX 0x7 +#define TPM_SC_TOF_MASK (0x1 << 7) +#define TPM_CNT 0x14 +#define TPM_MOD 0x18 +#define TPM_STATUS 0x1c +#define TPM_STATUS_CH0F BIT(0) +#define TPM_C0SC 0x20 +#define TPM_C0SC_CHIE BIT(6) +#define TPM_C0SC_MODE_SHIFT 2 +#define TPM_C0SC_MODE_MASK 0x3c +#define TPM_C0SC_MODE_SW_COMPARE 0x4 +#define TPM_C0SC_CHF_MASK (0x1 << 7) +#define TPM_C0V 0x24 + +static int counter_width __ro_after_init; +static void __iomem *timer_base __ro_after_init; + +static inline void tpm_timer_disable(void) +{ + unsigned int val; + + /* channel disable */ + val = readl(timer_base + TPM_C0SC); + val &= ~(TPM_C0SC_MODE_MASK | TPM_C0SC_CHIE); + writel(val, timer_base + TPM_C0SC); +} + +static inline void tpm_timer_enable(void) +{ + unsigned int val; + + /* channel enabled in sw compare mode */ + val = readl(timer_base + TPM_C0SC); + val |= (TPM_C0SC_MODE_SW_COMPARE << TPM_C0SC_MODE_SHIFT) | + TPM_C0SC_CHIE; + writel(val, timer_base + TPM_C0SC); +} + +static inline void tpm_irq_acknowledge(void) +{ + writel(TPM_STATUS_CH0F, timer_base + TPM_STATUS); +} + +static inline unsigned long tpm_read_counter(void) +{ + return readl(timer_base + TPM_CNT); +} + +#if defined(CONFIG_ARM) +static struct delay_timer tpm_delay_timer; + +static unsigned long tpm_read_current_timer(void) +{ + return tpm_read_counter(); +} + +static u64 notrace tpm_read_sched_clock(void) +{ + return tpm_read_counter(); +} +#endif + +static int tpm_set_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + unsigned long next, prev, now; + + prev = tpm_read_counter(); + next = prev + delta; + writel(next, timer_base + TPM_C0V); + now = tpm_read_counter(); + + /* + * Need to wait CNT increase at least 1 cycle to make sure + * the C0V has been updated into HW. + */ + if ((next & 0xffffffff) != readl(timer_base + TPM_C0V)) + while (now == tpm_read_counter()) + ; + + /* + * NOTE: We observed in a very small probability, the bus fabric + * contention between GPU and A7 may results a few cycles delay + * of writing CNT registers which may cause the min_delta event got + * missed, so we need add a ETIME check here in case it happened. + */ + return (now - prev) >= delta ? -ETIME : 0; +} + +static int tpm_set_state_oneshot(struct clock_event_device *evt) +{ + tpm_timer_enable(); + + return 0; +} + +static int tpm_set_state_shutdown(struct clock_event_device *evt) +{ + tpm_timer_disable(); + + return 0; +} + +static irqreturn_t tpm_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + tpm_irq_acknowledge(); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct timer_of to_tpm = { + .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK, + .clkevt = { + .name = "i.MX TPM Timer", + .rating = 200, + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ, + .set_state_shutdown = tpm_set_state_shutdown, + .set_state_oneshot = tpm_set_state_oneshot, + .set_next_event = tpm_set_next_event, + .cpumask = cpu_possible_mask, + }, + .of_irq = { + .handler = tpm_timer_interrupt, + .flags = IRQF_TIMER, + }, + .of_clk = { + .name = "per", + }, +}; + +static int __init tpm_clocksource_init(void) +{ +#if defined(CONFIG_ARM) + tpm_delay_timer.read_current_timer = &tpm_read_current_timer; + tpm_delay_timer.freq = timer_of_rate(&to_tpm) >> 3; + register_current_timer_delay(&tpm_delay_timer); + + sched_clock_register(tpm_read_sched_clock, counter_width, + timer_of_rate(&to_tpm) >> 3); +#endif + + return clocksource_mmio_init(timer_base + TPM_CNT, + "imx-tpm", + timer_of_rate(&to_tpm) >> 3, + to_tpm.clkevt.rating, + counter_width, + clocksource_mmio_readl_up); +} + +static void __init tpm_clockevent_init(void) +{ + clockevents_config_and_register(&to_tpm.clkevt, + timer_of_rate(&to_tpm) >> 3, + 300, + GENMASK(counter_width - 1, + 1)); +} + +static int __init tpm_timer_init(struct device_node *np) +{ + struct clk *ipg; + int ret; + + ipg = of_clk_get_by_name(np, "ipg"); + if (IS_ERR(ipg)) { + pr_err("tpm: failed to get ipg clk\n"); + return -ENODEV; + } + /* enable clk before accessing registers */ + ret = clk_prepare_enable(ipg); + if (ret) { + pr_err("tpm: ipg clock enable failed (%d)\n", ret); + clk_put(ipg); + return ret; + } + + ret = timer_of_init(np, &to_tpm); + if (ret) + return ret; + + timer_base = timer_of_base(&to_tpm); + + counter_width = (readl(timer_base + TPM_PARAM) + & TPM_PARAM_WIDTH_MASK) >> TPM_PARAM_WIDTH_SHIFT; + /* use rating 200 for 32-bit counter and 150 for 16-bit counter */ + to_tpm.clkevt.rating = counter_width == 0x20 ? 200 : 150; + + /* + * Initialize tpm module to a known state + * 1) Counter disabled + * 2) TPM counter operates in up counting mode + * 3) Timer Overflow Interrupt disabled + * 4) Channel0 disabled + * 5) DMA transfers disabled + */ + /* make sure counter is disabled */ + writel(0, timer_base + TPM_SC); + /* TOF is W1C */ + writel(TPM_SC_TOF_MASK, timer_base + TPM_SC); + writel(0, timer_base + TPM_CNT); + /* CHF is W1C */ + writel(TPM_C0SC_CHF_MASK, timer_base + TPM_C0SC); + + /* + * increase per cnt, + * div 8 for 32-bit counter and div 128 for 16-bit counter + */ + writel(TPM_SC_CMOD_INC_PER_CNT | + (counter_width == 0x20 ? + TPM_SC_CMOD_DIV_DEFAULT : TPM_SC_CMOD_DIV_MAX), + timer_base + TPM_SC); + + /* set MOD register to maximum for free running mode */ + writel(GENMASK(counter_width - 1, 0), timer_base + TPM_MOD); + + tpm_clockevent_init(); + + return tpm_clocksource_init(); +} +TIMER_OF_DECLARE(imx7ulp, "fsl,imx7ulp-tpm", tpm_timer_init); -- cgit v1.3.1