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
25 int kdump_status[NR_CPUS];
26 static atomic_t kdump_cpu_frozen;
27 atomic_t kdump_in_progress;
28 static int kdump_freeze_monarch;
29 static int kdump_on_init = 1;
30 static int kdump_on_fatal_mca = 1;
31
32 extern void ia64_dump_cpu_regs(void *);
33
34 static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
35
36 void
crash_save_this_cpu(void)37 crash_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
65 static int
kdump_wait_cpu_freeze(void)66 kdump_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
79 void
machine_crash_shutdown(struct pt_regs * pt)80 machine_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
128 static void
machine_kdump_on_init(void)129 machine_kdump_on_init(void)
130 {
131 crash_save_vmcoreinfo();
132 local_irq_disable();
133 kexec_disable_iosapic();
134 machine_kexec(ia64_kimage);
135 }
136
137 void
kdump_cpu_freeze(struct unw_frame_info * info,void * arg)138 kdump_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
156 static int
kdump_init_notifier(struct notifier_block * self,unsigned long val,void * data)157 kdump_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
220 static 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
238 static struct ctl_table sys_table[] = {
239 {
240 .procname = "kernel",
241 .mode = 0555,
242 .child = kdump_ctl_table,
243 },
244 { }
245 };
246 #endif
247
248 static int
machine_crash_setup(void)249 machine_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
267