arch/s390/kernel/machine_kexec.c

   1 /*
   2  * Copyright IBM Corp. 2005, 2011
   3  *
   4  * Author(s): Rolf Adelsberger,
   5  *            Heiko Carstens <heiko.carstens@de.ibm.com>
   6  *            Michael Holzheu <holzheu@linux.vnet.ibm.com>
   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 <linux/suspend.h>
  17 #include <asm/cio.h>
  18 #include <asm/setup.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/pgalloc.h>
  21 #include <asm/smp.h>
  22 #include <asm/reset.h>
  23 #include <asm/ipl.h>
  24 #include <asm/diag.h>
  25 #include <asm/elf.h>
  26 #include <asm/asm-offsets.h>
  27 #include <asm/os_info.h>
  28 #include <asm/switch_to.h>
  29
  30 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
  31
  32 extern const unsigned char relocate_kernel[];
  33 extern const unsigned long long relocate_kernel_len;
  34
  35 #ifdef CONFIG_CRASH_DUMP
  36
  37 /*
  38  * Create ELF notes for one CPU
  39  */
  40 static void add_elf_notes(int cpu)
  41 {
  42         struct save_area *sa = (void *) 4608 + store_prefix();
  43         void *ptr;
  44
  45         memcpy((void *) (4608UL + sa->pref_reg), sa, sizeof(*sa));
  46         ptr = (u64 *) per_cpu_ptr(crash_notes, cpu);
  47         ptr = fill_cpu_elf_notes(ptr, sa, NULL);
  48         memset(ptr, 0, sizeof(struct elf_note));
  49 }
  50
  51 /*
  52  * Initialize CPU ELF notes
  53  */
  54 static void setup_regs(void)
  55 {
  56         unsigned long sa = S390_lowcore.prefixreg_save_area + SAVE_AREA_BASE;
  57         struct _lowcore *lc;
  58         int cpu, this_cpu;
  59
  60         /* Get lowcore pointer from store status of this CPU (absolute zero) */
  61         lc = (struct _lowcore *)(unsigned long)S390_lowcore.prefixreg_save_area;
  62         this_cpu = smp_find_processor_id(stap());
  63         add_elf_notes(this_cpu);
  64         for_each_online_cpu(cpu) {
  65                 if (cpu == this_cpu)
  66                         continue;
  67                 if (smp_store_status(cpu))
  68                         continue;
  69                 add_elf_notes(cpu);
  70         }
  71         if (MACHINE_HAS_VX)
  72                 save_vx_regs_safe((void *) lc->vector_save_area_addr);
  73         /* Copy dump CPU store status info to absolute zero */
  74         memcpy((void *) SAVE_AREA_BASE, (void *) sa, sizeof(struct save_area));
  75 }
  76
  77 /*
  78  * PM notifier callback for kdump
  79  */
  80 static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
  81                                void *ptr)
  82 {
  83         switch (action) {
  84         case PM_SUSPEND_PREPARE:
  85         case PM_HIBERNATION_PREPARE:
  86                 if (crashk_res.start)
  87                         crash_map_reserved_pages();
  88                 break;
  89         case PM_POST_SUSPEND:
  90         case PM_POST_HIBERNATION:
  91                 if (crashk_res.start)
  92                         crash_unmap_reserved_pages();
  93                 break;
  94         default:
  95                 return NOTIFY_DONE;
  96         }
  97         return NOTIFY_OK;
  98 }
  99
 100 static int __init machine_kdump_pm_init(void)
 101 {
 102         pm_notifier(machine_kdump_pm_cb, 0);
 103         return 0;
 104 }
 105 arch_initcall(machine_kdump_pm_init);
 106
 107 /*
 108  * Start kdump: We expect here that a store status has been done on our CPU
 109  */
 110 static void __do_machine_kdump(void *image)
 111 {
 112         int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
 113
 114         __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
 115         start_kdump(1);
 116 }
 117 #endif
 118
 119 /*
 120  * Check if kdump checksums are valid: We call purgatory with parameter "0"
 121  */
 122 static int kdump_csum_valid(struct kimage *image)
 123 {
 124 #ifdef CONFIG_CRASH_DUMP
 125         int (*start_kdump)(int) = (void *)image->start;
 126         int rc;
 127
 128         __arch_local_irq_stnsm(0xfb); /* disable DAT */
 129         rc = start_kdump(0);
 130         __arch_local_irq_stosm(0x04); /* enable DAT */
 131         return rc ? 0 : -EINVAL;
 132 #else
 133         return -EINVAL;
 134 #endif
 135 }
 136
 137 /*
 138  * Map or unmap crashkernel memory
 139  */
 140 static void crash_map_pages(int enable)
 141 {
 142         unsigned long size = resource_size(&crashk_res);
 143
 144         BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
 145                size % KEXEC_CRASH_MEM_ALIGN);
 146         if (enable)
 147                 vmem_add_mapping(crashk_res.start, size);
 148         else {
 149                 vmem_remove_mapping(crashk_res.start, size);
 150                 if (size)
 151                         os_info_crashkernel_add(crashk_res.start, size);
 152                 else
 153                         os_info_crashkernel_add(0, 0);
 154         }
 155 }
 156
 157 /*
 158  * Map crashkernel memory
 159  */
 160 void crash_map_reserved_pages(void)
 161 {
 162         crash_map_pages(1);
 163 }
 164
 165 /*
 166  * Unmap crashkernel memory
 167  */
 168 void crash_unmap_reserved_pages(void)
 169 {
 170         crash_map_pages(0);
 171 }
 172
 173 /*
 174  * Give back memory to hypervisor before new kdump is loaded
 175  */
 176 static int machine_kexec_prepare_kdump(void)
 177 {
 178 #ifdef CONFIG_CRASH_DUMP
 179         if (MACHINE_IS_VM)
 180                 diag10_range(PFN_DOWN(crashk_res.start),
 181                              PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 182         return 0;
 183 #else
 184         return -EINVAL;
 185 #endif
 186 }
 187
 188 int machine_kexec_prepare(struct kimage *image)
 189 {
 190         void *reboot_code_buffer;
 191
 192         /* Can't replace kernel image since it is read-only. */
 193         if (ipl_flags & IPL_NSS_VALID)
 194                 return -EOPNOTSUPP;
 195
 196         if (image->type == KEXEC_TYPE_CRASH)
 197                 return machine_kexec_prepare_kdump();
 198
 199         /* We don't support anything but the default image type for now. */
 200         if (image->type != KEXEC_TYPE_DEFAULT)
 201                 return -EINVAL;
 202
 203         /* Get the destination where the assembler code should be copied to.*/
 204         reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
 205
 206         /* Then copy it */
 207         memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 208         return 0;
 209 }
 210
 211 void machine_kexec_cleanup(struct kimage *image)
 212 {
 213 }
 214
 215 void arch_crash_save_vmcoreinfo(void)
 216 {
 217         VMCOREINFO_SYMBOL(lowcore_ptr);
 218         VMCOREINFO_SYMBOL(high_memory);
 219         VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 220 }
 221
 222 void machine_shutdown(void)
 223 {
 224 }
 225
 226 void machine_crash_shutdown(struct pt_regs *regs)
 227 {
 228 }
 229
 230 /*
 231  * Do normal kexec
 232  */
 233 static void __do_machine_kexec(void *data)
 234 {
 235         relocate_kernel_t data_mover;
 236         struct kimage *image = data;
 237
 238         data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 239
 240         /* Call the moving routine */
 241         (*data_mover)(&image->head, image->start);
 242 }
 243
 244 /*
 245  * Reset system and call either kdump or normal kexec
 246  */
 247 static void __machine_kexec(void *data)
 248 {
 249         __arch_local_irq_stosm(0x04); /* enable DAT */
 250         pfault_fini();
 251         tracing_off();
 252         debug_locks_off();
 253 #ifdef CONFIG_CRASH_DUMP
 254         if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) {
 255
 256                 lgr_info_log();
 257                 s390_reset_system(setup_regs, __do_machine_kdump, data);
 258         } else
 259 #endif
 260                 s390_reset_system(NULL, __do_machine_kexec, data);
 261         disabled_wait((unsigned long) __builtin_return_address(0));
 262 }
 263
 264 /*
 265  * Do either kdump or normal kexec. In case of kdump we first ask
 266  * purgatory, if kdump checksums are valid.
 267  */
 268 void machine_kexec(struct kimage *image)
 269 {
 270         if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 271                 return;
 272         tracer_disable();
 273         smp_send_stop();
 274         smp_call_ipl_cpu(__machine_kexec, image);
 275 }