arch/s390/kernel/machine_kexec.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright IBM Corp. 2005, 2011
   4  *
   5  * Author(s): Rolf Adelsberger,
   6  *            Heiko Carstens <heiko.carstens@de.ibm.com>
   7  *            Michael Holzheu <holzheu@linux.vnet.ibm.com>
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/mm.h>
  12 #include <linux/kexec.h>
  13 #include <linux/delay.h>
  14 #include <linux/reboot.h>
  15 #include <linux/ftrace.h>
  16 #include <linux/debug_locks.h>
  17 #include <linux/suspend.h>
  18 #include <asm/cio.h>
  19 #include <asm/setup.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/smp.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/set_memory.h>
  30 #include <asm/switch_to.h>
  31 #include <asm/nmi.h>
  32
  33 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
  34
  35 extern const unsigned char relocate_kernel[];
  36 extern const unsigned long long relocate_kernel_len;
  37
  38 #ifdef CONFIG_CRASH_DUMP
  39
  40 /*
  41  * PM notifier callback for kdump
  42  */
  43 static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
  44                                void *ptr)
  45 {
  46         switch (action) {
  47         case PM_SUSPEND_PREPARE:
  48         case PM_HIBERNATION_PREPARE:
  49                 if (kexec_crash_image)
  50                         arch_kexec_unprotect_crashkres();
  51                 break;
  52         case PM_POST_SUSPEND:
  53         case PM_POST_HIBERNATION:
  54                 if (kexec_crash_image)
  55                         arch_kexec_protect_crashkres();
  56                 break;
  57         default:
  58                 return NOTIFY_DONE;
  59         }
  60         return NOTIFY_OK;
  61 }
  62
  63 static int __init machine_kdump_pm_init(void)
  64 {
  65         pm_notifier(machine_kdump_pm_cb, 0);
  66         return 0;
  67 }
  68 arch_initcall(machine_kdump_pm_init);
  69
  70 /*
  71  * Reset the system, copy boot CPU registers to absolute zero,
  72  * and jump to the kdump image
  73  */
  74 static void __do_machine_kdump(void *image)
  75 {
  76         int (*start_kdump)(int);
  77         unsigned long prefix;
  78
  79         /* store_status() saved the prefix register to lowcore */
  80         prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
  81
  82         /* Now do the reset  */
  83         s390_reset_system();
  84
  85         /*
  86          * Copy dump CPU store status info to absolute zero.
  87          * This need to be done *after* s390_reset_system set the
  88          * prefix register of this CPU to zero
  89          */
  90         memcpy((void *) __LC_FPREGS_SAVE_AREA,
  91                (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);
  92
  93         __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
  94         start_kdump = (void *)((struct kimage *) image)->start;
  95         start_kdump(1);
  96
  97         /* Die if start_kdump returns */
  98         disabled_wait((unsigned long) __builtin_return_address(0));
  99 }
 100
 101 /*
 102  * Start kdump: create a LGR log entry, store status of all CPUs and
 103  * branch to __do_machine_kdump.
 104  */
 105 static noinline void __machine_kdump(void *image)
 106 {
 107         struct mcesa *mcesa;
 108         union ctlreg2 cr2_old, cr2_new;
 109         int this_cpu, cpu;
 110
 111         lgr_info_log();
 112         /* Get status of the other CPUs */
 113         this_cpu = smp_find_processor_id(stap());
 114         for_each_online_cpu(cpu) {
 115                 if (cpu == this_cpu)
 116                         continue;
 117                 if (smp_store_status(cpu))
 118                         continue;
 119         }
 120         /* Store status of the boot CPU */
 121         mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
 122         if (MACHINE_HAS_VX)
 123                 save_vx_regs((__vector128 *) mcesa->vector_save_area);
 124         if (MACHINE_HAS_GS) {
 125                 __ctl_store(cr2_old.val, 2, 2);
 126                 cr2_new = cr2_old;
 127                 cr2_new.gse = 1;
 128                 __ctl_load(cr2_new.val, 2, 2);
 129                 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area);
 130                 __ctl_load(cr2_old.val, 2, 2);
 131         }
 132         /*
 133          * To create a good backchain for this CPU in the dump store_status
 134          * is passed the address of a function. The address is saved into
 135          * the PSW save area of the boot CPU and the function is invoked as
 136          * a tail call of store_status. The backchain in the dump will look
 137          * like this:
 138          *   restart_int_handler ->  __machine_kexec -> __do_machine_kdump
 139          * The call to store_status() will not return.
 140          */
 141         store_status(__do_machine_kdump, image);
 142 }
 143 #endif
 144
 145 static unsigned long do_start_kdump(unsigned long addr)
 146 {
 147         struct kimage *image = (struct kimage *) addr;
 148         int (*start_kdump)(int) = (void *)image->start;
 149         int rc;
 150
 151         __arch_local_irq_stnsm(0xfb); /* disable DAT */
 152         rc = start_kdump(0);
 153         __arch_local_irq_stosm(0x04); /* enable DAT */
 154         return rc;
 155 }
 156
 157 /*
 158  * Check if kdump checksums are valid: We call purgatory with parameter "0"
 159  */
 160 static bool kdump_csum_valid(struct kimage *image)
 161 {
 162 #ifdef CONFIG_CRASH_DUMP
 163         int rc;
 164
 165         rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image);
 166         return rc == 0;
 167 #else
 168         return false;
 169 #endif
 170 }
 171
 172 #ifdef CONFIG_CRASH_DUMP
 173
 174 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
 175 {
 176         unsigned long addr, size;
 177
 178         for (addr = begin; addr < end; addr += PAGE_SIZE)
 179                 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
 180         size = begin - crashk_res.start;
 181         if (size)
 182                 os_info_crashkernel_add(crashk_res.start, size);
 183         else
 184                 os_info_crashkernel_add(0, 0);
 185 }
 186
 187 static void crash_protect_pages(int protect)
 188 {
 189         unsigned long size;
 190
 191         if (!crashk_res.end)
 192                 return;
 193         size = resource_size(&crashk_res);
 194         if (protect)
 195                 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT);
 196         else
 197                 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT);
 198 }
 199
 200 void arch_kexec_protect_crashkres(void)
 201 {
 202         crash_protect_pages(1);
 203 }
 204
 205 void arch_kexec_unprotect_crashkres(void)
 206 {
 207         crash_protect_pages(0);
 208 }
 209
 210 #endif
 211
 212 /*
 213  * Give back memory to hypervisor before new kdump is loaded
 214  */
 215 static int machine_kexec_prepare_kdump(void)
 216 {
 217 #ifdef CONFIG_CRASH_DUMP
 218         if (MACHINE_IS_VM)
 219                 diag10_range(PFN_DOWN(crashk_res.start),
 220                              PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 221         return 0;
 222 #else
 223         return -EINVAL;
 224 #endif
 225 }
 226
 227 int machine_kexec_prepare(struct kimage *image)
 228 {
 229         void *reboot_code_buffer;
 230
 231         if (image->type == KEXEC_TYPE_CRASH)
 232                 return machine_kexec_prepare_kdump();
 233
 234         /* We don't support anything but the default image type for now. */
 235         if (image->type != KEXEC_TYPE_DEFAULT)
 236                 return -EINVAL;
 237
 238         /* Get the destination where the assembler code should be copied to.*/
 239         reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
 240
 241         /* Then copy it */
 242         memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 243         return 0;
 244 }
 245
 246 void machine_kexec_cleanup(struct kimage *image)
 247 {
 248 }
 249
 250 void arch_crash_save_vmcoreinfo(void)
 251 {
 252         VMCOREINFO_SYMBOL(lowcore_ptr);
 253         VMCOREINFO_SYMBOL(high_memory);
 254         VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 255         mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
 256 }
 257
 258 void machine_shutdown(void)
 259 {
 260 }
 261
 262 void machine_crash_shutdown(struct pt_regs *regs)
 263 {
 264         set_os_info_reipl_block();
 265 }
 266
 267 /*
 268  * Do normal kexec
 269  */
 270 static void __do_machine_kexec(void *data)
 271 {
 272         relocate_kernel_t data_mover;
 273         struct kimage *image = data;
 274
 275         s390_reset_system();
 276         data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 277
 278         __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */
 279         /* Call the moving routine */
 280         (*data_mover)(&image->head, image->start);
 281
 282         /* Die if kexec returns */
 283         disabled_wait((unsigned long) __builtin_return_address(0));
 284 }
 285
 286 /*
 287  * Reset system and call either kdump or normal kexec
 288  */
 289 static void __machine_kexec(void *data)
 290 {
 291         __arch_local_irq_stosm(0x04); /* enable DAT */
 292         pfault_fini();
 293         tracing_off();
 294         debug_locks_off();
 295 #ifdef CONFIG_CRASH_DUMP
 296         if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
 297                 __machine_kdump(data);
 298 #endif
 299         __do_machine_kexec(data);
 300 }
 301
 302 /*
 303  * Do either kdump or normal kexec. In case of kdump we first ask
 304  * purgatory, if kdump checksums are valid.
 305  */
 306 void machine_kexec(struct kimage *image)
 307 {
 308         if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 309                 return;
 310         tracer_disable();
 311         smp_send_stop();
 312         smp_call_ipl_cpu(__machine_kexec, image);
 313 }