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 --- fs/proc/stat.c | 180 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 180 insertions(+) create mode 100644 fs/proc/stat.c (limited to 'fs/proc/stat.c') diff --git a/fs/proc/stat.c b/fs/proc/stat.c new file mode 100644 index 000000000..79b42f2bf --- /dev/null +++ b/fs/proc/stat.c @@ -0,0 +1,180 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef arch_irq_stat_cpu +#define arch_irq_stat_cpu(cpu) 0 +#endif + +static void show_irq_gap(struct seq_file *p, unsigned int gap) +{ + static const char zeros[] = " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0"; + + while (gap > 0) { + unsigned int inc; + + inc = min_t(unsigned int, gap, ARRAY_SIZE(zeros) / 2); + seq_write(p, zeros, 2 * inc); + gap -= inc; + } +} + +static void show_all_irqs(struct seq_file *p) +{ + unsigned int i, next = 0; + + for_each_active_irq(i) { + show_irq_gap(p, i - next); + seq_put_decimal_ull(p, " ", kstat_irqs_usr(i)); + next = i + 1; + } + show_irq_gap(p, irq_get_nr_irqs() - next); +} + +static int show_stat(struct seq_file *p, void *v) +{ + int i, j; + u64 user, nice, system, idle, iowait, irq, softirq, steal; + u64 guest, guest_nice; + u64 sum = 0; + u64 sum_softirq = 0; + unsigned int per_softirq_sums[NR_SOFTIRQS] = {0}; + struct timespec64 boottime; + + user = nice = system = idle = iowait = + irq = softirq = steal = 0; + guest = guest_nice = 0; + getboottime64(&boottime); + /* shift boot timestamp according to the timens offset */ + timens_sub_boottime(&boottime); + + for_each_possible_cpu(i) { + struct kernel_cpustat kcpustat; + u64 *cpustat = kcpustat.cpustat; + + kcpustat_cpu_fetch(&kcpustat, i); + + user += cpustat[CPUTIME_USER]; + nice += cpustat[CPUTIME_NICE]; + system += cpustat[CPUTIME_SYSTEM]; + idle += cpustat[CPUTIME_IDLE]; + iowait += cpustat[CPUTIME_IOWAIT]; + irq += cpustat[CPUTIME_IRQ]; + softirq += cpustat[CPUTIME_SOFTIRQ]; + steal += cpustat[CPUTIME_STEAL]; + guest += cpustat[CPUTIME_GUEST]; + guest_nice += cpustat[CPUTIME_GUEST_NICE]; + sum += kstat_cpu_irqs_sum(i); + sum += arch_irq_stat_cpu(i); + + for (j = 0; j < NR_SOFTIRQS; j++) { + unsigned int softirq_stat = kstat_softirqs_cpu(j, i); + + per_softirq_sums[j] += softirq_stat; + sum_softirq += softirq_stat; + } + } + + seq_put_decimal_ull(p, "cpu ", nsec_to_clock_t(user)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(system)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice)); + seq_putc(p, '\n'); + + for_each_online_cpu(i) { + struct kernel_cpustat kcpustat; + u64 *cpustat = kcpustat.cpustat; + + kcpustat_cpu_fetch(&kcpustat, i); + + /* Copy values here to work around gcc-2.95.3, gcc-2.96 */ + user = cpustat[CPUTIME_USER]; + nice = cpustat[CPUTIME_NICE]; + system = cpustat[CPUTIME_SYSTEM]; + idle = cpustat[CPUTIME_IDLE]; + iowait = cpustat[CPUTIME_IOWAIT]; + irq = cpustat[CPUTIME_IRQ]; + softirq = cpustat[CPUTIME_SOFTIRQ]; + steal = cpustat[CPUTIME_STEAL]; + guest = cpustat[CPUTIME_GUEST]; + guest_nice = cpustat[CPUTIME_GUEST_NICE]; + seq_printf(p, "cpu%d", i); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(user)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(system)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest)); + seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice)); + seq_putc(p, '\n'); + } + seq_put_decimal_ull(p, "intr ", (unsigned long long)sum); + + show_all_irqs(p); + + seq_printf(p, + "\nctxt %llu\n" + "btime %llu\n" + "processes %lu\n" + "procs_running %u\n" + "procs_blocked %u\n", + nr_context_switches(), + (unsigned long long)boottime.tv_sec, + total_forks, + nr_running(), + nr_iowait()); + + seq_put_decimal_ull(p, "softirq ", (unsigned long long)sum_softirq); + + for (i = 0; i < NR_SOFTIRQS; i++) + seq_put_decimal_ull(p, " ", per_softirq_sums[i]); + seq_putc(p, '\n'); + + return 0; +} + +static int stat_open(struct inode *inode, struct file *file) +{ + unsigned int size = 1024 + 128 * num_online_cpus(); + + /* minimum size to display an interrupt count : 2 bytes */ + size += 2 * irq_get_nr_irqs(); + return single_open_size(file, show_stat, NULL, size); +} + +static const struct proc_ops stat_proc_ops = { + .proc_flags = PROC_ENTRY_PERMANENT, + .proc_open = stat_open, + .proc_read_iter = seq_read_iter, + .proc_lseek = seq_lseek, + .proc_release = single_release, +}; + +static int __init proc_stat_init(void) +{ + proc_create("stat", 0, NULL, &stat_proc_ops); + return 0; +} +fs_initcall(proc_stat_init); -- cgit v1.3.1