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machine_kexec.c
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1 /*
2  * Copyright IBM Corp. 2005, 2011
3  *
4  * Author(s): Rolf Adelsberger,
5  * Heiko Carstens <[email protected]>
6  * Michael Holzheu <[email protected]>
7  */
8 
9 #include <linux/device.h>
10 #include <linux/mm.h>
11 #include <linux/kexec.h>
12 #include <linux/delay.h>
13 #include <linux/reboot.h>
14 #include <linux/ftrace.h>
15 #include <linux/debug_locks.h>
16 #include <asm/cio.h>
17 #include <asm/setup.h>
18 #include <asm/pgtable.h>
19 #include <asm/pgalloc.h>
20 #include <asm/smp.h>
21 #include <asm/reset.h>
22 #include <asm/ipl.h>
23 #include <asm/diag.h>
24 #include <asm/elf.h>
25 #include <asm/asm-offsets.h>
26 #include <asm/os_info.h>
27 
28 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
29 
30 extern const unsigned char relocate_kernel[];
31 extern const unsigned long long relocate_kernel_len;
32 
33 #ifdef CONFIG_CRASH_DUMP
34 
35 /*
36  * Create ELF notes for one CPU
37  */
38 static void add_elf_notes(int cpu)
39 {
40  struct save_area *sa = (void *) 4608 + store_prefix();
41  void *ptr;
42 
43  memcpy((void *) (4608UL + sa->pref_reg), sa, sizeof(*sa));
44  ptr = (u64 *) per_cpu_ptr(crash_notes, cpu);
45  ptr = fill_cpu_elf_notes(ptr, sa);
46  memset(ptr, 0, sizeof(struct elf_note));
47 }
48 
49 /*
50  * Initialize CPU ELF notes
51  */
52 void setup_regs(void)
53 {
54  unsigned long sa = S390_lowcore.prefixreg_save_area + SAVE_AREA_BASE;
55  int cpu, this_cpu;
56 
57  this_cpu = smp_find_processor_id(stap());
58  add_elf_notes(this_cpu);
59  for_each_online_cpu(cpu) {
60  if (cpu == this_cpu)
61  continue;
62  if (smp_store_status(cpu))
63  continue;
64  add_elf_notes(cpu);
65  }
66  /* Copy dump CPU store status info to absolute zero */
67  memcpy((void *) SAVE_AREA_BASE, (void *) sa, sizeof(struct save_area));
68 }
69 
70 #endif
71 
72 /*
73  * Start kdump: We expect here that a store status has been done on our CPU
74  */
75 static void __do_machine_kdump(void *image)
76 {
77 #ifdef CONFIG_CRASH_DUMP
78  int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
79 
80  setup_regs();
82  start_kdump(1);
83 #endif
84 }
85 
86 /*
87  * Check if kdump checksums are valid: We call purgatory with parameter "0"
88  */
89 static int kdump_csum_valid(struct kimage *image)
90 {
91 #ifdef CONFIG_CRASH_DUMP
92  int (*start_kdump)(int) = (void *)image->start;
93  int rc;
94 
95  __arch_local_irq_stnsm(0xfb); /* disable DAT */
96  rc = start_kdump(0);
97  __arch_local_irq_stosm(0x04); /* enable DAT */
98  return rc ? 0 : -EINVAL;
99 #else
100  return -EINVAL;
101 #endif
102 }
103 
104 /*
105  * Map or unmap crashkernel memory
106  */
107 static void crash_map_pages(int enable)
108 {
109  unsigned long size = resource_size(&crashk_res);
110 
112  size % KEXEC_CRASH_MEM_ALIGN);
113  if (enable)
114  vmem_add_mapping(crashk_res.start, size);
115  else {
116  vmem_remove_mapping(crashk_res.start, size);
117  if (size)
118  os_info_crashkernel_add(crashk_res.start, size);
119  else
121  }
122 }
123 
124 /*
125  * Map crashkernel memory
126  */
128 {
129  crash_map_pages(1);
130 }
131 
132 /*
133  * Unmap crashkernel memory
134  */
136 {
137  crash_map_pages(0);
138 }
139 
140 /*
141  * Give back memory to hypervisor before new kdump is loaded
142  */
143 static int machine_kexec_prepare_kdump(void)
144 {
145 #ifdef CONFIG_CRASH_DUMP
146  if (MACHINE_IS_VM)
147  diag10_range(PFN_DOWN(crashk_res.start),
148  PFN_DOWN(crashk_res.end - crashk_res.start + 1));
149  return 0;
150 #else
151  return -EINVAL;
152 #endif
153 }
154 
155 int machine_kexec_prepare(struct kimage *image)
156 {
157  void *reboot_code_buffer;
158 
159  /* Can't replace kernel image since it is read-only. */
160  if (ipl_flags & IPL_NSS_VALID)
161  return -EOPNOTSUPP;
162 
163  if (image->type == KEXEC_TYPE_CRASH)
164  return machine_kexec_prepare_kdump();
165 
166  /* We don't support anything but the default image type for now. */
167  if (image->type != KEXEC_TYPE_DEFAULT)
168  return -EINVAL;
169 
170  /* Get the destination where the assembler code should be copied to.*/
171  reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
172 
173  /* Then copy it */
174  memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
175  return 0;
176 }
177 
178 void machine_kexec_cleanup(struct kimage *image)
179 {
180 }
181 
183 {
184  VMCOREINFO_SYMBOL(lowcore_ptr);
185  VMCOREINFO_SYMBOL(high_memory);
186  VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
187 }
188 
190 {
191 }
192 
194 {
195 }
196 
197 /*
198  * Do normal kexec
199  */
200 static void __do_machine_kexec(void *data)
201 {
202  relocate_kernel_t data_mover;
203  struct kimage *image = data;
204 
205  data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
206 
207  /* Call the moving routine */
208  (*data_mover)(&image->head, image->start);
209 }
210 
211 /*
212  * Reset system and call either kdump or normal kexec
213  */
214 static void __machine_kexec(void *data)
215 {
216  struct kimage *image = data;
217 
218  __arch_local_irq_stosm(0x04); /* enable DAT */
219  pfault_fini();
220  tracing_off();
221  debug_locks_off();
222  if (image->type == KEXEC_TYPE_CRASH) {
223  lgr_info_log();
224  s390_reset_system(__do_machine_kdump, data);
225  } else {
226  s390_reset_system(__do_machine_kexec, data);
227  }
228  disabled_wait((unsigned long) __builtin_return_address(0));
229 }
230 
231 /*
232  * Do either kdump or normal kexec. In case of kdump we first ask
233  * purgatory, if kdump checksums are valid.
234  */
235 void machine_kexec(struct kimage *image)
236 {
237  if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
238  return;
239  tracer_disable();
240  smp_send_stop();
241  smp_call_ipl_cpu(__machine_kexec, image);
242 }