Linux Kernel  3.7.1
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crash.c
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1 /*
2  * arch/ia64/kernel/crash.c
3  *
4  * Architecture specific (ia64) functions for kexec based crash dumps.
5  *
6  * Created by: Khalid Aziz <[email protected]>
7  * Copyright (C) 2005 Hewlett-Packard Development Company, L.P.
8  * Copyright (C) 2005 Intel Corp Zou Nan hai <[email protected]>
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 
24 static atomic_t kdump_cpu_frozen;
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
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
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 
55 
56 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
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
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  */
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  */
117  ia64_set_psr_mc(); /* mask MCA/INIT */
118  if (atomic_inc_return(&kdump_in_progress) != 1)
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  */
139  /* not all cpu response to IPI, send INIT to freeze them */
140  if (kdump_wait_cpu_freeze()) {
142  /* wait again, don't go ahead if possible */
143  kdump_wait_cpu_freeze();
144  }
145 #endif
146 }
147 
148 static void
149 machine_kdump_on_init(void)
150 {
155 }
156 
157 void
159 {
160  int cpuid;
161 
163  cpuid = smp_processor_id();
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
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) {
185  if (!kdump_freeze_monarch)
186  break;
187  /* fall through */
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)
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) {
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;
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;
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,
247  },
248  {
249  .procname = "kdump_on_fatal_mca",
250  .data = &kdump_on_fatal_mca,
251  .maxlen = sizeof(int),
252  .mode = 0644,
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
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