1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * arch/ia64/kernel/crash.c
  4 *
  5 * Architecture specific (ia64) functions for kexec based crash dumps.
  6 *
  7 * Created by: Khalid Aziz <khalid.aziz@hp.com>
  8 * Copyright (C) 2005 Hewlett-Packard Development Company, L.P.
  9 * Copyright (C) 2005 Intel Corp	Zou Nan hai <nanhai.zou@intel.com>
 10 *
 11 */
 12#include <linux/smp.h>
 13#include <linux/delay.h>
 14#include <linux/crash_dump.h>
 15#include <linux/memblock.h>
 16#include <linux/kexec.h>
 17#include <linux/elfcore.h>
 18#include <linux/reboot.h>
 19#include <linux/sysctl.h>
 20#include <linux/init.h>
 21#include <linux/kdebug.h>
 22
 23#include <asm/mca.h>
 24
 25int kdump_status[NR_CPUS];
 26static atomic_t kdump_cpu_frozen;
 27atomic_t kdump_in_progress;
 28static int kdump_freeze_monarch;
 29static int kdump_on_init = 1;
 30static int kdump_on_fatal_mca = 1;
 31
 32extern void ia64_dump_cpu_regs(void *);
 33
 34static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
 35
 36void
 37crash_save_this_cpu(void)
 38{
 39	void *buf;
 40	unsigned long cfm, sof, sol;
 41
 42	int cpu = smp_processor_id();
 43	struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu);
 44
 45	elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
 46	memset(prstatus, 0, sizeof(*prstatus));
 47	prstatus->common.pr_pid = current->pid;
 48
 49	ia64_dump_cpu_regs(dst);
 50	cfm = dst[43];
 51	sol = (cfm >> 7) & 0x7f;
 52	sof = cfm & 0x7f;
 53	dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46],
 54			sof - sol);
 55
 56	buf = (u64 *) per_cpu_ptr(crash_notes, cpu);
 57	if (!buf)
 58		return;
 59	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus,
 60			sizeof(*prstatus));
 61	final_note(buf);
 62}
 63
 64#ifdef CONFIG_SMP
 65static int
 66kdump_wait_cpu_freeze(void)
 67{
 68	int cpu_num = num_online_cpus() - 1;
 69	int timeout = 1000;
 70	while(timeout-- > 0) {
 71		if (atomic_read(&kdump_cpu_frozen) == cpu_num)
 72			return 0;
 73		udelay(1000);
 74	}
 75	return 1;
 76}
 77#endif
 78
 79void
 80machine_crash_shutdown(struct pt_regs *pt)
 81{
 82	/* This function is only called after the system
 83	 * has paniced or is otherwise in a critical state.
 84	 * The minimum amount of code to allow a kexec'd kernel
 85	 * to run successfully needs to happen here.
 86	 *
 87	 * In practice this means shooting down the other cpus in
 88	 * an SMP system.
 89	 */
 90	kexec_disable_iosapic();
 91#ifdef CONFIG_SMP
 92	/*
 93	 * If kdump_on_init is set and an INIT is asserted here, kdump will
 94	 * be started again via INIT monarch.
 95	 */
 96	local_irq_disable();
 97	ia64_set_psr_mc();	/* mask MCA/INIT */
 98	if (atomic_inc_return(&kdump_in_progress) != 1)
 99		unw_init_running(kdump_cpu_freeze, NULL);
100
101	/*
102	 * Now this cpu is ready for kdump.
103	 * Stop all others by IPI or INIT.  They could receive INIT from
104	 * outside and might be INIT monarch, but only thing they have to
105	 * do is falling into kdump_cpu_freeze().
106	 *
107	 * If an INIT is asserted here:
108	 * - All receivers might be slaves, since some of cpus could already
109	 *   be frozen and INIT might be masked on monarch.  In this case,
110	 *   all slaves will be frozen soon since kdump_in_progress will let
111	 *   them into DIE_INIT_SLAVE_LEAVE.
112	 * - One might be a monarch, but INIT rendezvous will fail since
113	 *   at least this cpu already have INIT masked so it never join
114	 *   to the rendezvous.  In this case, all slaves and monarch will
115	 *   be frozen soon with no wait since the INIT rendezvous is skipped
116	 *   by kdump_in_progress.
117	 */
118	kdump_smp_send_stop();
119	/* not all cpu response to IPI, send INIT to freeze them */
120	if (kdump_wait_cpu_freeze()) {
121		kdump_smp_send_init();
122		/* wait again, don't go ahead if possible */
123		kdump_wait_cpu_freeze();
124	}
125#endif
126}
127
128static void
129machine_kdump_on_init(void)
130{
131	crash_save_vmcoreinfo();
132	local_irq_disable();
133	kexec_disable_iosapic();
134	machine_kexec(ia64_kimage);
135}
136
137void
138kdump_cpu_freeze(struct unw_frame_info *info, void *arg)
139{
140	int cpuid;
141
142	local_irq_disable();
143	cpuid = smp_processor_id();
144	crash_save_this_cpu();
145	current->thread.ksp = (__u64)info->sw - 16;
146
147	ia64_set_psr_mc();	/* mask MCA/INIT and stop reentrance */
148
149	atomic_inc(&kdump_cpu_frozen);
150	kdump_status[cpuid] = 1;
151	mb();
152	for (;;)
153		cpu_relax();
154}
155
156static int
157kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data)
158{
159	struct ia64_mca_notify_die *nd;
160	struct die_args *args = data;
161
162	if (atomic_read(&kdump_in_progress)) {
163		switch (val) {
164		case DIE_INIT_MONARCH_LEAVE:
165			if (!kdump_freeze_monarch)
166				break;
167			fallthrough;
168		case DIE_INIT_SLAVE_LEAVE:
169		case DIE_INIT_MONARCH_ENTER:
170		case DIE_MCA_RENDZVOUS_LEAVE:
171			unw_init_running(kdump_cpu_freeze, NULL);
172			break;
173		}
174	}
175
176	if (!kdump_on_init && !kdump_on_fatal_mca)
177		return NOTIFY_DONE;
178
179	if (!ia64_kimage) {
180		if (val == DIE_INIT_MONARCH_LEAVE)
181			ia64_mca_printk(KERN_NOTICE
182					"%s: kdump not configured\n",
183					__func__);
184		return NOTIFY_DONE;
185	}
186
187	if (val != DIE_INIT_MONARCH_LEAVE &&
188	    val != DIE_INIT_MONARCH_PROCESS &&
189	    val != DIE_MCA_MONARCH_LEAVE)
190		return NOTIFY_DONE;
191
192	nd = (struct ia64_mca_notify_die *)args->err;
193
194	switch (val) {
195	case DIE_INIT_MONARCH_PROCESS:
196		/* Reason code 1 means machine check rendezvous*/
197		if (kdump_on_init && (nd->sos->rv_rc != 1)) {
198			if (atomic_inc_return(&kdump_in_progress) != 1)
199				kdump_freeze_monarch = 1;
200		}
201		break;
202	case DIE_INIT_MONARCH_LEAVE:
203		/* Reason code 1 means machine check rendezvous*/
204		if (kdump_on_init && (nd->sos->rv_rc != 1))
205			machine_kdump_on_init();
206		break;
207	case DIE_MCA_MONARCH_LEAVE:
208		/* *(nd->data) indicate if MCA is recoverable */
209		if (kdump_on_fatal_mca && !(*(nd->data))) {
210			if (atomic_inc_return(&kdump_in_progress) == 1)
211				machine_kdump_on_init();
212			/* We got fatal MCA while kdump!? No way!! */
213		}
214		break;
215	}
216	return NOTIFY_DONE;
217}
218
219#ifdef CONFIG_SYSCTL
220static struct ctl_table kdump_ctl_table[] = {
221	{
222		.procname = "kdump_on_init",
223		.data = &kdump_on_init,
224		.maxlen = sizeof(int),
225		.mode = 0644,
226		.proc_handler = proc_dointvec,
227	},
228	{
229		.procname = "kdump_on_fatal_mca",
230		.data = &kdump_on_fatal_mca,
231		.maxlen = sizeof(int),
232		.mode = 0644,
233		.proc_handler = proc_dointvec,
234	},
235	{ }
236};
237
238static struct ctl_table sys_table[] = {
239	{
240	  .procname = "kernel",
241	  .mode = 0555,
242	  .child = kdump_ctl_table,
243	},
244	{ }
245};
246#endif
247
248static int
249machine_crash_setup(void)
250{
251	/* be notified before default_monarch_init_process */
252	static struct notifier_block kdump_init_notifier_nb = {
253		.notifier_call = kdump_init_notifier,
254		.priority = 1,
255	};
256	int ret;
257	if((ret = register_die_notifier(&kdump_init_notifier_nb)) != 0)
258		return ret;
259#ifdef CONFIG_SYSCTL
260	register_sysctl_table(sys_table);
261#endif
262	return 0;
263}
264
265__initcall(machine_crash_setup);
266