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