arch/s390/kernel/machine_kexec.c

   1 /*
   2  * arch/s390/kernel/machine_kexec.c
   3  *
   4  * Copyright IBM Corp. 2005,2011
   5  *
   6  * Author(s): Rolf Adelsberger,
   7  *            Heiko Carstens <heiko.carstens@de.ibm.com>
   8  *            Michael Holzheu <holzheu@linux.vnet.ibm.com>
   9  */
  10
  11 #include <linux/device.h>
  12 #include <linux/mm.h>
  13 #include <linux/kexec.h>
  14 #include <linux/delay.h>
  15 #include <linux/reboot.h>
  16 #include <linux/ftrace.h>
  17 #include <asm/cio.h>
  18 #include <asm/setup.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/pgalloc.h>
  21 #include <asm/system.h>
  22 #include <asm/smp.h>
  23 #include <asm/reset.h>
  24 #include <asm/ipl.h>
  25 #include <asm/diag.h>
  26 #include <asm/asm-offsets.h>
  27
  28 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
  29
  30 extern const unsigned char relocate_kernel[];
  31 extern const unsigned long long relocate_kernel_len;
  32
  33 #ifdef CONFIG_CRASH_DUMP
  34
  35 void *fill_cpu_elf_notes(void *ptr, struct save_area *sa);
  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);
  48         memset(ptr, 0, sizeof(struct elf_note));
  49 }
  50
  51 /*
  52  * Store status of next available physical CPU
  53  */
  54 static int store_status_next(int start_cpu, int this_cpu)
  55 {
  56         struct save_area *sa = (void *) 4608 + store_prefix();
  57         int cpu, rc;
  58
  59         for (cpu = start_cpu; cpu < 65536; cpu++) {
  60                 if (cpu == this_cpu)
  61                         continue;
  62                 do {
  63                         rc = raw_sigp(cpu, sigp_stop_and_store_status);
  64                 } while (rc == sigp_busy);
  65                 if (rc != sigp_order_code_accepted)
  66                         continue;
  67                 if (sa->pref_reg)
  68                         return cpu;
  69         }
  70         return -1;
  71 }
  72
  73 /*
  74  * Initialize CPU ELF notes
  75  */
  76 void setup_regs(void)
  77 {
  78         unsigned long sa = S390_lowcore.prefixreg_save_area + SAVE_AREA_BASE;
  79         int cpu, this_cpu, phys_cpu = 0, first = 1;
  80
  81         this_cpu = stap();
  82
  83         if (!S390_lowcore.prefixreg_save_area)
  84                 first = 0;
  85         for_each_online_cpu(cpu) {
  86                 if (first) {
  87                         add_elf_notes(cpu);
  88                         first = 0;
  89                         continue;
  90                 }
  91                 phys_cpu = store_status_next(phys_cpu, this_cpu);
  92                 if (phys_cpu == -1)
  93                         break;
  94                 add_elf_notes(cpu);
  95                 phys_cpu++;
  96         }
  97         /* Copy dump CPU store status info to absolute zero */
  98         memcpy((void *) SAVE_AREA_BASE, (void *) sa, sizeof(struct save_area));
  99 }
 100
 101 #endif
 102
 103 /*
 104  * Start kdump: We expect here that a store status has been done on our CPU
 105  */
 106 static void __do_machine_kdump(void *image)
 107 {
 108 #ifdef CONFIG_CRASH_DUMP
 109         int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
 110
 111         __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
 112         setup_regs();
 113         start_kdump(1);
 114 #endif
 115 }
 116
 117 /*
 118  * Check if kdump checksums are valid: We call purgatory with parameter "0"
 119  */
 120 static int kdump_csum_valid(struct kimage *image)
 121 {
 122 #ifdef CONFIG_CRASH_DUMP
 123         int (*start_kdump)(int) = (void *)image->start;
 124         int rc;
 125
 126         __arch_local_irq_stnsm(0xfb); /* disable DAT */
 127         rc = start_kdump(0);
 128         __arch_local_irq_stosm(0x04); /* enable DAT */
 129         return rc ? 0 : -EINVAL;
 130 #else
 131         return -EINVAL;
 132 #endif
 133 }
 134
 135 /*
 136  * Map or unmap crashkernel memory
 137  */
 138 static void crash_map_pages(int enable)
 139 {
 140         unsigned long size = resource_size(&crashk_res);
 141
 142         BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
 143                size % KEXEC_CRASH_MEM_ALIGN);
 144         if (enable)
 145                 vmem_add_mapping(crashk_res.start, size);
 146         else
 147                 vmem_remove_mapping(crashk_res.start, size);
 148 }
 149
 150 /*
 151  * Map crashkernel memory
 152  */
 153 void crash_map_reserved_pages(void)
 154 {
 155         crash_map_pages(1);
 156 }
 157
 158 /*
 159  * Unmap crashkernel memory
 160  */
 161 void crash_unmap_reserved_pages(void)
 162 {
 163         crash_map_pages(0);
 164 }
 165
 166 /*
 167  * Give back memory to hypervisor before new kdump is loaded
 168  */
 169 static int machine_kexec_prepare_kdump(void)
 170 {
 171 #ifdef CONFIG_CRASH_DUMP
 172         if (MACHINE_IS_VM)
 173                 diag10_range(PFN_DOWN(crashk_res.start),
 174                              PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 175         return 0;
 176 #else
 177         return -EINVAL;
 178 #endif
 179 }
 180
 181 int machine_kexec_prepare(struct kimage *image)
 182 {
 183         void *reboot_code_buffer;
 184
 185         /* Can't replace kernel image since it is read-only. */
 186         if (ipl_flags & IPL_NSS_VALID)
 187                 return -ENOSYS;
 188
 189         if (image->type == KEXEC_TYPE_CRASH)
 190                 return machine_kexec_prepare_kdump();
 191
 192         /* We don't support anything but the default image type for now. */
 193         if (image->type != KEXEC_TYPE_DEFAULT)
 194                 return -EINVAL;
 195
 196         /* Get the destination where the assembler code should be copied to.*/
 197         reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
 198
 199         /* Then copy it */
 200         memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 201         return 0;
 202 }
 203
 204 void machine_kexec_cleanup(struct kimage *image)
 205 {
 206 }
 207
 208 void arch_crash_save_vmcoreinfo(void)
 209 {
 210         VMCOREINFO_SYMBOL(lowcore_ptr);
 211         VMCOREINFO_SYMBOL(high_memory);
 212         VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 213 }
 214
 215 void machine_shutdown(void)
 216 {
 217 }
 218
 219 /*
 220  * Do normal kexec
 221  */
 222 static void __do_machine_kexec(void *data)
 223 {
 224         relocate_kernel_t data_mover;
 225         struct kimage *image = data;
 226
 227         data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 228
 229         /* Call the moving routine */
 230         (*data_mover)(&image->head, image->start);
 231 }
 232
 233 /*
 234  * Reset system and call either kdump or normal kexec
 235  */
 236 static void __machine_kexec(void *data)
 237 {
 238         struct kimage *image = data;
 239
 240         pfault_fini();
 241         if (image->type == KEXEC_TYPE_CRASH)
 242                 s390_reset_system(__do_machine_kdump, data);
 243         else
 244                 s390_reset_system(__do_machine_kexec, data);
 245         disabled_wait((unsigned long) __builtin_return_address(0));
 246 }
 247
 248 /*
 249  * Do either kdump or normal kexec. In case of kdump we first ask
 250  * purgatory, if kdump checksums are valid.
 251  */
 252 void machine_kexec(struct kimage *image)
 253 {
 254         if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 255                 return;
 256         tracer_disable();
 257         smp_send_stop();
 258         smp_switch_to_ipl_cpu(__machine_kexec, image);
 259 }