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 #endif
 107
 108 /*
 109  * Start kdump: We expect here that a store status has been done on our CPU
 110  */
 111 static void __do_machine_kdump(void *image)
 112 {
 113 #ifdef CONFIG_CRASH_DUMP
 114         int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
 115
 116         setup_regs();
 117         __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
 118         start_kdump(1);
 119 #endif
 120 }
 121
 122 /*
 123  * Check if kdump checksums are valid: We call purgatory with parameter "0"
 124  */
 125 static int kdump_csum_valid(struct kimage *image)
 126 {
 127 #ifdef CONFIG_CRASH_DUMP
 128         int (*start_kdump)(int) = (void *)image->start;
 129         int rc;
 130
 131         __arch_local_irq_stnsm(0xfb); /* disable DAT */
 132         rc = start_kdump(0);
 133         __arch_local_irq_stosm(0x04); /* enable DAT */
 134         return rc ? 0 : -EINVAL;
 135 #else
 136         return -EINVAL;
 137 #endif
 138 }
 139
 140 /*
 141  * Map or unmap crashkernel memory
 142  */
 143 static void crash_map_pages(int enable)
 144 {
 145         unsigned long size = resource_size(&crashk_res);
 146
 147         BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
 148                size % KEXEC_CRASH_MEM_ALIGN);
 149         if (enable)
 150                 vmem_add_mapping(crashk_res.start, size);
 151         else {
 152                 vmem_remove_mapping(crashk_res.start, size);
 153                 if (size)
 154                         os_info_crashkernel_add(crashk_res.start, size);
 155                 else
 156                         os_info_crashkernel_add(0, 0);
 157         }
 158 }
 159
 160 /*
 161  * Map crashkernel memory
 162  */
 163 void crash_map_reserved_pages(void)
 164 {
 165         crash_map_pages(1);
 166 }
 167
 168 /*
 169  * Unmap crashkernel memory
 170  */
 171 void crash_unmap_reserved_pages(void)
 172 {
 173         crash_map_pages(0);
 174 }
 175
 176 /*
 177  * Give back memory to hypervisor before new kdump is loaded
 178  */
 179 static int machine_kexec_prepare_kdump(void)
 180 {
 181 #ifdef CONFIG_CRASH_DUMP
 182         if (MACHINE_IS_VM)
 183                 diag10_range(PFN_DOWN(crashk_res.start),
 184                              PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 185         return 0;
 186 #else
 187         return -EINVAL;
 188 #endif
 189 }
 190
 191 int machine_kexec_prepare(struct kimage *image)
 192 {
 193         void *reboot_code_buffer;
 194
 195         /* Can't replace kernel image since it is read-only. */
 196         if (ipl_flags & IPL_NSS_VALID)
 197                 return -EOPNOTSUPP;
 198
 199         if (image->type == KEXEC_TYPE_CRASH)
 200                 return machine_kexec_prepare_kdump();
 201
 202         /* We don't support anything but the default image type for now. */
 203         if (image->type != KEXEC_TYPE_DEFAULT)
 204                 return -EINVAL;
 205
 206         /* Get the destination where the assembler code should be copied to.*/
 207         reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
 208
 209         /* Then copy it */
 210         memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 211         return 0;
 212 }
 213
 214 void machine_kexec_cleanup(struct kimage *image)
 215 {
 216 }
 217
 218 void arch_crash_save_vmcoreinfo(void)
 219 {
 220         VMCOREINFO_SYMBOL(lowcore_ptr);
 221         VMCOREINFO_SYMBOL(high_memory);
 222         VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 223 }
 224
 225 void machine_shutdown(void)
 226 {
 227 }
 228
 229 void machine_crash_shutdown(struct pt_regs *regs)
 230 {
 231 }
 232
 233 /*
 234  * Do normal kexec
 235  */
 236 static void __do_machine_kexec(void *data)
 237 {
 238         relocate_kernel_t data_mover;
 239         struct kimage *image = data;
 240
 241         data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 242
 243         /* Call the moving routine */
 244         (*data_mover)(&image->head, image->start);
 245 }
 246
 247 /*
 248  * Reset system and call either kdump or normal kexec
 249  */
 250 static void __machine_kexec(void *data)
 251 {
 252         struct kimage *image = data;
 253
 254         __arch_local_irq_stosm(0x04); /* enable DAT */
 255         pfault_fini();
 256         tracing_off();
 257         debug_locks_off();
 258         if (image->type == KEXEC_TYPE_CRASH) {
 259                 lgr_info_log();
 260                 s390_reset_system(__do_machine_kdump, data);
 261         } else {
 262                 s390_reset_system(__do_machine_kexec, data);
 263         }
 264         disabled_wait((unsigned long) __builtin_return_address(0));
 265 }
 266
 267 /*
 268  * Do either kdump or normal kexec. In case of kdump we first ask
 269  * purgatory, if kdump checksums are valid.
 270  */
 271 void machine_kexec(struct kimage *image)
 272 {
 273         if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 274                 return;
 275         tracer_disable();
 276         smp_send_stop();
 277         smp_call_ipl_cpu(__machine_kexec, image);
 278 }