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