1 /*
2 * arch/ia64/kernel/crash.c
3 *
4 * Architecture specific (ia64) functions for kexec based crash dumps.
5 *
6 * Created by: Khalid Aziz <khalid.aziz@hp.com>
7 * Copyright (C) 2005 Hewlett-Packard Development Company, L.P.
8 * Copyright (C) 2005 Intel Corp Zou Nan hai <nanhai.zou@intel.com>
9 *
10 */
11 #include <linux/smp.h>
12 #include <linux/delay.h>
13 #include <linux/crash_dump.h>
14 #include <linux/bootmem.h>
15 #include <linux/kexec.h>
16 #include <linux/elfcore.h>
17 #include <linux/sysctl.h>
18 #include <linux/init.h>
19 #include <linux/kdebug.h>
20
21 #include <asm/mca.h>
22
23 int kdump_status[NR_CPUS];
24 static atomic_t kdump_cpu_frozen;
25 atomic_t kdump_in_progress;
26 static int kdump_freeze_monarch;
27 static int kdump_on_init = 1;
28 static int kdump_on_fatal_mca = 1;
29
30 static inline Elf64_Word
append_elf_note(Elf64_Word * buf,char * name,unsigned type,void * data,size_t data_len)31 *append_elf_note(Elf64_Word *buf, char *name, unsigned type, void *data,
32 size_t data_len)
33 {
34 struct elf_note *note = (struct elf_note *)buf;
35 note->n_namesz = strlen(name) + 1;
36 note->n_descsz = data_len;
37 note->n_type = type;
38 buf += (sizeof(*note) + 3)/4;
39 memcpy(buf, name, note->n_namesz);
40 buf += (note->n_namesz + 3)/4;
41 memcpy(buf, data, data_len);
42 buf += (data_len + 3)/4;
43 return buf;
44 }
45
46 static void
final_note(void * buf)47 final_note(void *buf)
48 {
49 memset(buf, 0, sizeof(struct elf_note));
50 }
51
52 extern void ia64_dump_cpu_regs(void *);
53
54 static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
55
56 void
crash_save_this_cpu(void)57 crash_save_this_cpu(void)
58 {
59 void *buf;
60 unsigned long cfm, sof, sol;
61
62 int cpu = smp_processor_id();
63 struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu);
64
65 elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
66 memset(prstatus, 0, sizeof(*prstatus));
67 prstatus->pr_pid = current->pid;
68
69 ia64_dump_cpu_regs(dst);
70 cfm = dst[43];
71 sol = (cfm >> 7) & 0x7f;
72 sof = cfm & 0x7f;
73 dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46],
74 sof - sol);
75
76 buf = (u64 *) per_cpu_ptr(crash_notes, cpu);
77 if (!buf)
78 return;
79 buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus,
80 sizeof(*prstatus));
81 final_note(buf);
82 }
83
84 #ifdef CONFIG_SMP
85 static int
kdump_wait_cpu_freeze(void)86 kdump_wait_cpu_freeze(void)
87 {
88 int cpu_num = num_online_cpus() - 1;
89 int timeout = 1000;
90 while(timeout-- > 0) {
91 if (atomic_read(&kdump_cpu_frozen) == cpu_num)
92 return 0;
93 udelay(1000);
94 }
95 return 1;
96 }
97 #endif
98
99 void
machine_crash_shutdown(struct pt_regs * pt)100 machine_crash_shutdown(struct pt_regs *pt)
101 {
102 /* This function is only called after the system
103 * has paniced or is otherwise in a critical state.
104 * The minimum amount of code to allow a kexec'd kernel
105 * to run successfully needs to happen here.
106 *
107 * In practice this means shooting down the other cpus in
108 * an SMP system.
109 */
110 kexec_disable_iosapic();
111 #ifdef CONFIG_SMP
112 /*
113 * If kdump_on_init is set and an INIT is asserted here, kdump will
114 * be started again via INIT monarch.
115 */
116 local_irq_disable();
117 ia64_set_psr_mc(); /* mask MCA/INIT */
118 if (atomic_inc_return(&kdump_in_progress) != 1)
119 unw_init_running(kdump_cpu_freeze, NULL);
120
121 /*
122 * Now this cpu is ready for kdump.
123 * Stop all others by IPI or INIT. They could receive INIT from
124 * outside and might be INIT monarch, but only thing they have to
125 * do is falling into kdump_cpu_freeze().
126 *
127 * If an INIT is asserted here:
128 * - All receivers might be slaves, since some of cpus could already
129 * be frozen and INIT might be masked on monarch. In this case,
130 * all slaves will be frozen soon since kdump_in_progress will let
131 * them into DIE_INIT_SLAVE_LEAVE.
132 * - One might be a monarch, but INIT rendezvous will fail since
133 * at least this cpu already have INIT masked so it never join
134 * to the rendezvous. In this case, all slaves and monarch will
135 * be frozen soon with no wait since the INIT rendezvous is skipped
136 * by kdump_in_progress.
137 */
138 kdump_smp_send_stop();
139 /* not all cpu response to IPI, send INIT to freeze them */
140 if (kdump_wait_cpu_freeze()) {
141 kdump_smp_send_init();
142 /* wait again, don't go ahead if possible */
143 kdump_wait_cpu_freeze();
144 }
145 #endif
146 }
147
148 static void
machine_kdump_on_init(void)149 machine_kdump_on_init(void)
150 {
151 crash_save_vmcoreinfo();
152 local_irq_disable();
153 kexec_disable_iosapic();
154 machine_kexec(ia64_kimage);
155 }
156
157 void
kdump_cpu_freeze(struct unw_frame_info * info,void * arg)158 kdump_cpu_freeze(struct unw_frame_info *info, void *arg)
159 {
160 int cpuid;
161
162 local_irq_disable();
163 cpuid = smp_processor_id();
164 crash_save_this_cpu();
165 current->thread.ksp = (__u64)info->sw - 16;
166
167 ia64_set_psr_mc(); /* mask MCA/INIT and stop reentrance */
168
169 atomic_inc(&kdump_cpu_frozen);
170 kdump_status[cpuid] = 1;
171 mb();
172 for (;;)
173 cpu_relax();
174 }
175
176 static int
kdump_init_notifier(struct notifier_block * self,unsigned long val,void * data)177 kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data)
178 {
179 struct ia64_mca_notify_die *nd;
180 struct die_args *args = data;
181
182 if (atomic_read(&kdump_in_progress)) {
183 switch (val) {
184 case DIE_INIT_MONARCH_LEAVE:
185 if (!kdump_freeze_monarch)
186 break;
187 /* fall through */
188 case DIE_INIT_SLAVE_LEAVE:
189 case DIE_INIT_MONARCH_ENTER:
190 case DIE_MCA_RENDZVOUS_LEAVE:
191 unw_init_running(kdump_cpu_freeze, NULL);
192 break;
193 }
194 }
195
196 if (!kdump_on_init && !kdump_on_fatal_mca)
197 return NOTIFY_DONE;
198
199 if (!ia64_kimage) {
200 if (val == DIE_INIT_MONARCH_LEAVE)
201 ia64_mca_printk(KERN_NOTICE
202 "%s: kdump not configured\n",
203 __func__);
204 return NOTIFY_DONE;
205 }
206
207 if (val != DIE_INIT_MONARCH_LEAVE &&
208 val != DIE_INIT_MONARCH_PROCESS &&
209 val != DIE_MCA_MONARCH_LEAVE)
210 return NOTIFY_DONE;
211
212 nd = (struct ia64_mca_notify_die *)args->err;
213
214 switch (val) {
215 case DIE_INIT_MONARCH_PROCESS:
216 /* Reason code 1 means machine check rendezvous*/
217 if (kdump_on_init && (nd->sos->rv_rc != 1)) {
218 if (atomic_inc_return(&kdump_in_progress) != 1)
219 kdump_freeze_monarch = 1;
220 }
221 break;
222 case DIE_INIT_MONARCH_LEAVE:
223 /* Reason code 1 means machine check rendezvous*/
224 if (kdump_on_init && (nd->sos->rv_rc != 1))
225 machine_kdump_on_init();
226 break;
227 case DIE_MCA_MONARCH_LEAVE:
228 /* *(nd->data) indicate if MCA is recoverable */
229 if (kdump_on_fatal_mca && !(*(nd->data))) {
230 if (atomic_inc_return(&kdump_in_progress) == 1)
231 machine_kdump_on_init();
232 /* We got fatal MCA while kdump!? No way!! */
233 }
234 break;
235 }
236 return NOTIFY_DONE;
237 }
238
239 #ifdef CONFIG_SYSCTL
240 static ctl_table kdump_ctl_table[] = {
241 {
242 .procname = "kdump_on_init",
243 .data = &kdump_on_init,
244 .maxlen = sizeof(int),
245 .mode = 0644,
246 .proc_handler = proc_dointvec,
247 },
248 {
249 .procname = "kdump_on_fatal_mca",
250 .data = &kdump_on_fatal_mca,
251 .maxlen = sizeof(int),
252 .mode = 0644,
253 .proc_handler = proc_dointvec,
254 },
255 { }
256 };
257
258 static ctl_table sys_table[] = {
259 {
260 .procname = "kernel",
261 .mode = 0555,
262 .child = kdump_ctl_table,
263 },
264 { }
265 };
266 #endif
267
268 static int
machine_crash_setup(void)269 machine_crash_setup(void)
270 {
271 /* be notified before default_monarch_init_process */
272 static struct notifier_block kdump_init_notifier_nb = {
273 .notifier_call = kdump_init_notifier,
274 .priority = 1,
275 };
276 int ret;
277 if((ret = register_die_notifier(&kdump_init_notifier_nb)) != 0)
278 return ret;
279 #ifdef CONFIG_SYSCTL
280 register_sysctl_table(sys_table);
281 #endif
282 return 0;
283 }
284
285 __initcall(machine_crash_setup);
286
287