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/cacheflush.h>
  28 #include <asm/os_info.h>
  29 #include <asm/switch_to.h>
  30
  31 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
  32
  33 extern const unsigned char relocate_kernel[];
  34 extern const unsigned long long relocate_kernel_len;
  35
  36 #ifdef CONFIG_CRASH_DUMP
  37
  38 /*
  39  * PM notifier callback for kdump
  40  */
  41 static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
  42                                void *ptr)
  43 {
  44         switch (action) {
  45         case PM_SUSPEND_PREPARE:
  46         case PM_HIBERNATION_PREPARE:
  47                 if (kexec_crash_image)
  48                         arch_kexec_unprotect_crashkres();
  49                 break;
  50         case PM_POST_SUSPEND:
  51         case PM_POST_HIBERNATION:
  52                 if (kexec_crash_image)
  53                         arch_kexec_protect_crashkres();
  54                 break;
  55         default:
  56                 return NOTIFY_DONE;
  57         }
  58         return NOTIFY_OK;
  59 }
  60
  61 static int __init machine_kdump_pm_init(void)
  62 {
  63         pm_notifier(machine_kdump_pm_cb, 0);
  64         return 0;
  65 }
  66 arch_initcall(machine_kdump_pm_init);
  67
  68 /*
  69  * Reset the system, copy boot CPU registers to absolute zero,
  70  * and jump to the kdump image
  71  */
  72 static void __do_machine_kdump(void *image)
  73 {
  74         int (*start_kdump)(int);
  75         unsigned long prefix;
  76
  77         /* store_status() saved the prefix register to lowcore */
  78         prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
  79
  80         /* Now do the reset  */
  81         s390_reset_system();
  82
  83         /*
  84          * Copy dump CPU store status info to absolute zero.
  85          * This need to be done *after* s390_reset_system set the
  86          * prefix register of this CPU to zero
  87          */
  88         memcpy((void *) __LC_FPREGS_SAVE_AREA,
  89                (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);
  90
  91         __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
  92         start_kdump = (void *)((struct kimage *) image)->start;
  93         start_kdump(1);
  94
  95         /* Die if start_kdump returns */
  96         disabled_wait((unsigned long) __builtin_return_address(0));
  97 }
  98
  99 /*
 100  * Start kdump: create a LGR log entry, store status of all CPUs and
 101  * branch to __do_machine_kdump.
 102  */
 103 static noinline void __machine_kdump(void *image)
 104 {
 105         int this_cpu, cpu;
 106
 107         lgr_info_log();
 108         /* Get status of the other CPUs */
 109         this_cpu = smp_find_processor_id(stap());
 110         for_each_online_cpu(cpu) {
 111                 if (cpu == this_cpu)
 112                         continue;
 113                 if (smp_store_status(cpu))
 114                         continue;
 115         }
 116         /* Store status of the boot CPU */
 117         if (MACHINE_HAS_VX)
 118                 save_vx_regs((void *) &S390_lowcore.vector_save_area);
 119         /*
 120          * To create a good backchain for this CPU in the dump store_status
 121          * is passed the address of a function. The address is saved into
 122          * the PSW save area of the boot CPU and the function is invoked as
 123          * a tail call of store_status. The backchain in the dump will look
 124          * like this:
 125          *   restart_int_handler ->  __machine_kexec -> __do_machine_kdump
 126          * The call to store_status() will not return.
 127          */
 128         store_status(__do_machine_kdump, image);
 129 }
 130 #endif
 131
 132 /*
 133  * Check if kdump checksums are valid: We call purgatory with parameter "0"
 134  */
 135 static int kdump_csum_valid(struct kimage *image)
 136 {
 137 #ifdef CONFIG_CRASH_DUMP
 138         int (*start_kdump)(int) = (void *)image->start;
 139         int rc;
 140
 141         __arch_local_irq_stnsm(0xfb); /* disable DAT */
 142         rc = start_kdump(0);
 143         __arch_local_irq_stosm(0x04); /* enable DAT */
 144         return rc ? 0 : -EINVAL;
 145 #else
 146         return -EINVAL;
 147 #endif
 148 }
 149
 150 #ifdef CONFIG_CRASH_DUMP
 151
 152 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
 153 {
 154         unsigned long addr, size;
 155
 156         for (addr = begin; addr < end; addr += PAGE_SIZE)
 157                 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
 158         size = begin - crashk_res.start;
 159         if (size)
 160                 os_info_crashkernel_add(crashk_res.start, size);
 161         else
 162                 os_info_crashkernel_add(0, 0);
 163 }
 164
 165 static void crash_protect_pages(int protect)
 166 {
 167         unsigned long size;
 168
 169         if (!crashk_res.end)
 170                 return;
 171         size = resource_size(&crashk_res);
 172         if (protect)
 173                 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT);
 174         else
 175                 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT);
 176 }
 177
 178 void arch_kexec_protect_crashkres(void)
 179 {
 180         crash_protect_pages(1);
 181 }
 182
 183 void arch_kexec_unprotect_crashkres(void)
 184 {
 185         crash_protect_pages(0);
 186 }
 187
 188 #endif
 189
 190 /*
 191  * Give back memory to hypervisor before new kdump is loaded
 192  */
 193 static int machine_kexec_prepare_kdump(void)
 194 {
 195 #ifdef CONFIG_CRASH_DUMP
 196         if (MACHINE_IS_VM)
 197                 diag10_range(PFN_DOWN(crashk_res.start),
 198                              PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 199         return 0;
 200 #else
 201         return -EINVAL;
 202 #endif
 203 }
 204
 205 int machine_kexec_prepare(struct kimage *image)
 206 {
 207         void *reboot_code_buffer;
 208
 209         /* Can't replace kernel image since it is read-only. */
 210         if (ipl_flags & IPL_NSS_VALID)
 211                 return -EOPNOTSUPP;
 212
 213         if (image->type == KEXEC_TYPE_CRASH)
 214                 return machine_kexec_prepare_kdump();
 215
 216         /* We don't support anything but the default image type for now. */
 217         if (image->type != KEXEC_TYPE_DEFAULT)
 218                 return -EINVAL;
 219
 220         /* Get the destination where the assembler code should be copied to.*/
 221         reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
 222
 223         /* Then copy it */
 224         memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 225         return 0;
 226 }
 227
 228 void machine_kexec_cleanup(struct kimage *image)
 229 {
 230 }
 231
 232 void arch_crash_save_vmcoreinfo(void)
 233 {
 234         VMCOREINFO_SYMBOL(lowcore_ptr);
 235         VMCOREINFO_SYMBOL(high_memory);
 236         VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 237 }
 238
 239 void machine_shutdown(void)
 240 {
 241 }
 242
 243 void machine_crash_shutdown(struct pt_regs *regs)
 244 {
 245 }
 246
 247 /*
 248  * Do normal kexec
 249  */
 250 static void __do_machine_kexec(void *data)
 251 {
 252         relocate_kernel_t data_mover;
 253         struct kimage *image = data;
 254
 255         s390_reset_system();
 256         data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 257
 258         /* Call the moving routine */
 259         (*data_mover)(&image->head, image->start);
 260
 261         /* Die if kexec returns */
 262         disabled_wait((unsigned long) __builtin_return_address(0));
 263 }
 264
 265 /*
 266  * Reset system and call either kdump or normal kexec
 267  */
 268 static void __machine_kexec(void *data)
 269 {
 270         __arch_local_irq_stosm(0x04); /* enable DAT */
 271         pfault_fini();
 272         tracing_off();
 273         debug_locks_off();
 274 #ifdef CONFIG_CRASH_DUMP
 275         if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
 276                 __machine_kdump(data);
 277 #endif
 278         __do_machine_kexec(data);
 279 }
 280
 281 /*
 282  * Do either kdump or normal kexec. In case of kdump we first ask
 283  * purgatory, if kdump checksums are valid.
 284  */
 285 void machine_kexec(struct kimage *image)
 286 {
 287         if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 288                 return;
 289         tracer_disable();
 290         smp_send_stop();
 291         smp_call_ipl_cpu(__machine_kexec, image);
 292 }