| 1 | // SPDX-License-Identifier: GPL-2.0 |
|---|---|
| 2 | /* |
| 3 | * lib/smp_processor_id.c |
| 4 | * |
| 5 | * DEBUG_PREEMPT variant of smp_processor_id(). |
| 6 | */ |
| 7 | #include <linux/export.h> |
| 8 | #include <linux/kprobes.h> |
| 9 | #include <linux/sched.h> |
| 10 | |
| 11 | noinstr static |
| 12 | unsigned int check_preemption_disabled(const char *what1, const char *what2) |
| 13 | { |
| 14 | int this_cpu = raw_smp_processor_id(); |
| 15 | |
| 16 | if (likely(preempt_count())) |
| 17 | goto out; |
| 18 | |
| 19 | if (irqs_disabled()) |
| 20 | goto out; |
| 21 | |
| 22 | if (is_percpu_thread()) |
| 23 | goto out; |
| 24 | |
| 25 | #ifdef CONFIG_SMP |
| 26 | if (current->migration_disabled) |
| 27 | goto out; |
| 28 | #endif |
| 29 | |
| 30 | /* |
| 31 | * It is valid to assume CPU-locality during early bootup: |
| 32 | */ |
| 33 | if (system_state < SYSTEM_SCHEDULING) |
| 34 | goto out; |
| 35 | |
| 36 | /* |
| 37 | * Avoid recursion: |
| 38 | */ |
| 39 | preempt_disable_notrace(); |
| 40 | |
| 41 | instrumentation_begin(); |
| 42 | if (!printk_ratelimit()) |
| 43 | goto out_enable; |
| 44 | |
| 45 | printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n", |
| 46 | what1, what2, preempt_count() - 1, current->comm, current->pid); |
| 47 | |
| 48 | printk("caller is %pS\n", __builtin_return_address(0)); |
| 49 | dump_stack(); |
| 50 | |
| 51 | out_enable: |
| 52 | instrumentation_end(); |
| 53 | preempt_enable_no_resched_notrace(); |
| 54 | out: |
| 55 | return this_cpu; |
| 56 | } |
| 57 | |
| 58 | noinstr unsigned int debug_smp_processor_id(void) |
| 59 | { |
| 60 | return check_preemption_disabled(what1: "smp_processor_id", what2: ""); |
| 61 | } |
| 62 | EXPORT_SYMBOL(debug_smp_processor_id); |
| 63 | |
| 64 | noinstr void __this_cpu_preempt_check(const char *op) |
| 65 | { |
| 66 | check_preemption_disabled(what1: "__this_cpu_", what2: op); |
| 67 | } |
| 68 | EXPORT_SYMBOL(__this_cpu_preempt_check); |
| 69 |