cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

crash.c (2432B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/kernel.h>
      3#include <linux/smp.h>
      4#include <linux/reboot.h>
      5#include <linux/kexec.h>
      6#include <linux/memblock.h>
      7#include <linux/crash_dump.h>
      8#include <linux/delay.h>
      9#include <linux/irq.h>
     10#include <linux/types.h>
     11#include <linux/sched.h>
     12#include <linux/sched/task_stack.h>
     13
     14/* This keeps a track of which one is crashing cpu. */
     15static int crashing_cpu = -1;
     16static cpumask_t cpus_in_crash = CPU_MASK_NONE;
     17
     18#ifdef CONFIG_SMP
     19static void crash_shutdown_secondary(void *passed_regs)
     20{
     21	struct pt_regs *regs = passed_regs;
     22	int cpu = smp_processor_id();
     23
     24	/*
     25	 * If we are passed registers, use those.  Otherwise get the
     26	 * regs from the last interrupt, which should be correct, as
     27	 * we are in an interrupt.  But if the regs are not there,
     28	 * pull them from the top of the stack.  They are probably
     29	 * wrong, but we need something to keep from crashing again.
     30	 */
     31	if (!regs)
     32		regs = get_irq_regs();
     33	if (!regs)
     34		regs = task_pt_regs(current);
     35
     36	if (!cpu_online(cpu))
     37		return;
     38
     39	/* We won't be sent IPIs any more. */
     40	set_cpu_online(cpu, false);
     41
     42	local_irq_disable();
     43	if (!cpumask_test_cpu(cpu, &cpus_in_crash))
     44		crash_save_cpu(regs, cpu);
     45	cpumask_set_cpu(cpu, &cpus_in_crash);
     46
     47	while (!atomic_read(&kexec_ready_to_reboot))
     48		cpu_relax();
     49
     50	kexec_reboot();
     51
     52	/* NOTREACHED */
     53}
     54
     55static void crash_kexec_prepare_cpus(void)
     56{
     57	static int cpus_stopped;
     58	unsigned int msecs;
     59	unsigned int ncpus;
     60
     61	if (cpus_stopped)
     62		return;
     63
     64	ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
     65
     66	smp_call_function(crash_shutdown_secondary, NULL, 0);
     67	smp_wmb();
     68
     69	/*
     70	 * The crash CPU sends an IPI and wait for other CPUs to
     71	 * respond. Delay of at least 10 seconds.
     72	 */
     73	pr_emerg("Sending IPI to other cpus...\n");
     74	msecs = 10000;
     75	while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
     76		cpu_relax();
     77		mdelay(1);
     78	}
     79
     80	cpus_stopped = 1;
     81}
     82
     83/* Override the weak function in kernel/panic.c */
     84void crash_smp_send_stop(void)
     85{
     86	if (_crash_smp_send_stop)
     87		_crash_smp_send_stop();
     88
     89	crash_kexec_prepare_cpus();
     90}
     91
     92#else /* !defined(CONFIG_SMP)  */
     93static void crash_kexec_prepare_cpus(void) {}
     94#endif /* !defined(CONFIG_SMP)	*/
     95
     96void default_machine_crash_shutdown(struct pt_regs *regs)
     97{
     98	local_irq_disable();
     99	crashing_cpu = smp_processor_id();
    100	crash_save_cpu(regs, crashing_cpu);
    101	crash_kexec_prepare_cpus();
    102	cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
    103}