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  * PM notifier callback for kdump
  39  */
  40 static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
  41                                void *ptr)
  42 {
  43         switch (action) {
  44         case PM_SUSPEND_PREPARE:
  45         case PM_HIBERNATION_PREPARE:
  46                 if (crashk_res.start)
  47                         crash_map_reserved_pages();
  48                 break;
  49         case PM_POST_SUSPEND:
  50         case PM_POST_HIBERNATION:
  51                 if (crashk_res.start)
  52                         crash_unmap_reserved_pages();
  53                 break;
  54         default:
  55                 return NOTIFY_DONE;
  56         }
  57         return NOTIFY_OK;
  58 }
  59
  60 static int __init machine_kdump_pm_init(void)
  61 {
  62         pm_notifier(machine_kdump_pm_cb, 0);
  63         return 0;
  64 }
  65 arch_initcall(machine_kdump_pm_init);
  66
  67 /*
  68  * Reset the system, copy boot CPU registers to absolute zero,
  69  * and jump to the kdump image
  70  */
  71 static void __do_machine_kdump(void *image)
  72 {
  73         int (*start_kdump)(int);
  74         unsigned long prefix;
  75
  76         /* store_status() saved the prefix register to lowcore */
  77         prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
  78
  79         /* Now do the reset  */
  80         s390_reset_system();
  81
  82         /*
  83          * Copy dump CPU store status info to absolute zero.
  84          * This need to be done *after* s390_reset_system set the
  85          * prefix register of this CPU to zero
  86          */
  87         memcpy((void *) __LC_FPREGS_SAVE_AREA,
  88                (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);
  89
  90         __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
  91         start_kdump = (void *)((struct kimage *) image)->start;
  92         start_kdump(1);
  93
  94         /* Die if start_kdump returns */
  95         disabled_wait((unsigned long) __builtin_return_address(0));
  96 }
  97
  98 /*
  99  * Start kdump: create a LGR log entry, store status of all CPUs and
 100  * branch to __do_machine_kdump.
 101  */
 102 static noinline void __machine_kdump(void *image)
 103 {
 104         int this_cpu, cpu;
 105
 106         lgr_info_log();
 107         /* Get status of the other CPUs */
 108         this_cpu = smp_find_processor_id(stap());
 109         for_each_online_cpu(cpu) {
 110                 if (cpu == this_cpu)
 111                         continue;
 112                 if (smp_store_status(cpu))
 113                         continue;
 114         }
 115         /* Store status of the boot CPU */
 116         if (MACHINE_HAS_VX)
 117                 save_vx_regs((void *) &S390_lowcore.vector_save_area);
 118         /*
 119          * To create a good backchain for this CPU in the dump store_status
 120          * is passed the address of a function. The address is saved into
 121          * the PSW save area of the boot CPU and the function is invoked as
 122          * a tail call of store_status. The backchain in the dump will look
 123          * like this:
 124          *   restart_int_handler ->  __machine_kexec -> __do_machine_kdump
 125          * The call to store_status() will not return.
 126          */
 127         store_status(__do_machine_kdump, image);
 128 }
 129 #endif
 130
 131 /*
 132  * Check if kdump checksums are valid: We call purgatory with parameter "0"
 133  */
 134 static int kdump_csum_valid(struct kimage *image)
 135 {
 136 #ifdef CONFIG_CRASH_DUMP
 137         int (*start_kdump)(int) = (void *)image->start;
 138         int rc;
 139
 140         __arch_local_irq_stnsm(0xfb); /* disable DAT */
 141         rc = start_kdump(0);
 142         __arch_local_irq_stosm(0x04); /* enable DAT */
 143         return rc ? 0 : -EINVAL;
 144 #else
 145         return -EINVAL;
 146 #endif
 147 }
 148
 149 /*
 150  * Map or unmap crashkernel memory
 151  */
 152 static void crash_map_pages(int enable)
 153 {
 154         unsigned long size = resource_size(&crashk_res);
 155
 156         BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
 157                size % KEXEC_CRASH_MEM_ALIGN);
 158         if (enable)
 159                 vmem_add_mapping(crashk_res.start, size);
 160         else {
 161                 vmem_remove_mapping(crashk_res.start, size);
 162                 if (size)
 163                         os_info_crashkernel_add(crashk_res.start, size);
 164                 else
 165                         os_info_crashkernel_add(0, 0);
 166         }
 167 }
 168
 169 /*
 170  * Map crashkernel memory
 171  */
 172 void crash_map_reserved_pages(void)
 173 {
 174         crash_map_pages(1);
 175 }
 176
 177 /*
 178  * Unmap crashkernel memory
 179  */
 180 void crash_unmap_reserved_pages(void)
 181 {
 182         crash_map_pages(0);
 183 }
 184
 185 /*
 186  * Give back memory to hypervisor before new kdump is loaded
 187  */
 188 static int machine_kexec_prepare_kdump(void)
 189 {
 190 #ifdef CONFIG_CRASH_DUMP
 191         if (MACHINE_IS_VM)
 192                 diag10_range(PFN_DOWN(crashk_res.start),
 193                              PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 194         return 0;
 195 #else
 196         return -EINVAL;
 197 #endif
 198 }
 199
 200 int machine_kexec_prepare(struct kimage *image)
 201 {
 202         void *reboot_code_buffer;
 203
 204         /* Can't replace kernel image since it is read-only. */
 205         if (ipl_flags & IPL_NSS_VALID)
 206                 return -EOPNOTSUPP;
 207
 208         if (image->type == KEXEC_TYPE_CRASH)
 209                 return machine_kexec_prepare_kdump();
 210
 211         /* We don't support anything but the default image type for now. */
 212         if (image->type != KEXEC_TYPE_DEFAULT)
 213                 return -EINVAL;
 214
 215         /* Get the destination where the assembler code should be copied to.*/
 216         reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
 217
 218         /* Then copy it */
 219         memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 220         return 0;
 221 }
 222
 223 void machine_kexec_cleanup(struct kimage *image)
 224 {
 225 }
 226
 227 void arch_crash_save_vmcoreinfo(void)
 228 {
 229         VMCOREINFO_SYMBOL(lowcore_ptr);
 230         VMCOREINFO_SYMBOL(high_memory);
 231         VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 232 }
 233
 234 void machine_shutdown(void)
 235 {
 236 }
 237
 238 void machine_crash_shutdown(struct pt_regs *regs)
 239 {
 240 }
 241
 242 /*
 243  * Do normal kexec
 244  */
 245 static void __do_machine_kexec(void *data)
 246 {
 247         relocate_kernel_t data_mover;
 248         struct kimage *image = data;
 249
 250         s390_reset_system();
 251         data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 252
 253         /* Call the moving routine */
 254         (*data_mover)(&image->head, image->start);
 255
 256         /* Die if kexec returns */
 257         disabled_wait((unsigned long) __builtin_return_address(0));
 258 }
 259
 260 /*
 261  * Reset system and call either kdump or normal kexec
 262  */
 263 static void __machine_kexec(void *data)
 264 {
 265         __arch_local_irq_stosm(0x04); /* enable DAT */
 266         pfault_fini();
 267         tracing_off();
 268         debug_locks_off();
 269 #ifdef CONFIG_CRASH_DUMP
 270         if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
 271                 __machine_kdump(data);
 272 #endif
 273         __do_machine_kexec(data);
 274 }
 275
 276 /*
 277  * Do either kdump or normal kexec. In case of kdump we first ask
 278  * purgatory, if kdump checksums are valid.
 279  */
 280 void machine_kexec(struct kimage *image)
 281 {
 282         if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 283                 return;
 284         tracer_disable();
 285         smp_send_stop();
 286         smp_call_ipl_cpu(__machine_kexec, image);
 287 }