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 (kexec_crash_image) 47 arch_kexec_unprotect_crashkres(); 48 break; 49 case PM_POST_SUSPEND: 50 case PM_POST_HIBERNATION: 51 if (kexec_crash_image) 52 arch_kexec_protect_crashkres(); 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 /* Create initial mapping for crashkernel memory */ 64 arch_kexec_unprotect_crashkres(); 65 return 0; 66 } 67 arch_initcall(machine_kdump_pm_init); 68 69 /* 70 * Reset the system, copy boot CPU registers to absolute zero, 71 * and jump to the kdump image 72 */ 73 static void __do_machine_kdump(void *image) 74 { 75 int (*start_kdump)(int); 76 unsigned long prefix; 77 78 /* store_status() saved the prefix register to lowcore */ 79 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 80 81 /* Now do the reset */ 82 s390_reset_system(); 83 84 /* 85 * Copy dump CPU store status info to absolute zero. 86 * This need to be done *after* s390_reset_system set the 87 * prefix register of this CPU to zero 88 */ 89 memcpy((void *) __LC_FPREGS_SAVE_AREA, 90 (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512); 91 92 __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); 93 start_kdump = (void *)((struct kimage *) image)->start; 94 start_kdump(1); 95 96 /* Die if start_kdump returns */ 97 disabled_wait((unsigned long) __builtin_return_address(0)); 98 } 99 100 /* 101 * Start kdump: create a LGR log entry, store status of all CPUs and 102 * branch to __do_machine_kdump. 103 */ 104 static noinline void __machine_kdump(void *image) 105 { 106 int this_cpu, cpu; 107 108 lgr_info_log(); 109 /* Get status of the other CPUs */ 110 this_cpu = smp_find_processor_id(stap()); 111 for_each_online_cpu(cpu) { 112 if (cpu == this_cpu) 113 continue; 114 if (smp_store_status(cpu)) 115 continue; 116 } 117 /* Store status of the boot CPU */ 118 if (MACHINE_HAS_VX) 119 save_vx_regs((void *) &S390_lowcore.vector_save_area); 120 /* 121 * To create a good backchain for this CPU in the dump store_status 122 * is passed the address of a function. The address is saved into 123 * the PSW save area of the boot CPU and the function is invoked as 124 * a tail call of store_status. The backchain in the dump will look 125 * like this: 126 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 127 * The call to store_status() will not return. 128 */ 129 store_status(__do_machine_kdump, image); 130 } 131 #endif 132 133 /* 134 * Check if kdump checksums are valid: We call purgatory with parameter "0" 135 */ 136 static int kdump_csum_valid(struct kimage *image) 137 { 138 #ifdef CONFIG_CRASH_DUMP 139 int (*start_kdump)(int) = (void *)image->start; 140 int rc; 141 142 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 143 rc = start_kdump(0); 144 __arch_local_irq_stosm(0x04); /* enable DAT */ 145 return rc ? 0 : -EINVAL; 146 #else 147 return -EINVAL; 148 #endif 149 } 150 151 #ifdef CONFIG_CRASH_DUMP 152 153 /* 154 * Map or unmap crashkernel memory 155 */ 156 static void crash_map_pages(int enable) 157 { 158 unsigned long size = resource_size(&crashk_res); 159 160 BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN || 161 size % KEXEC_CRASH_MEM_ALIGN); 162 if (enable) 163 vmem_add_mapping(crashk_res.start, size); 164 else { 165 vmem_remove_mapping(crashk_res.start, size); 166 if (size) 167 os_info_crashkernel_add(crashk_res.start, size); 168 else 169 os_info_crashkernel_add(0, 0); 170 } 171 } 172 173 /* 174 * Unmap crashkernel memory 175 */ 176 void arch_kexec_protect_crashkres(void) 177 { 178 if (crashk_res.end) 179 crash_map_pages(0); 180 } 181 182 /* 183 * Map crashkernel memory 184 */ 185 void arch_kexec_unprotect_crashkres(void) 186 { 187 if (crashk_res.end) 188 crash_map_pages(1); 189 } 190 191 #endif 192 193 /* 194 * Give back memory to hypervisor before new kdump is loaded 195 */ 196 static int machine_kexec_prepare_kdump(void) 197 { 198 #ifdef CONFIG_CRASH_DUMP 199 if (MACHINE_IS_VM) 200 diag10_range(PFN_DOWN(crashk_res.start), 201 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 202 return 0; 203 #else 204 return -EINVAL; 205 #endif 206 } 207 208 int machine_kexec_prepare(struct kimage *image) 209 { 210 void *reboot_code_buffer; 211 212 /* Can't replace kernel image since it is read-only. */ 213 if (ipl_flags & IPL_NSS_VALID) 214 return -EOPNOTSUPP; 215 216 if (image->type == KEXEC_TYPE_CRASH) 217 return machine_kexec_prepare_kdump(); 218 219 /* We don't support anything but the default image type for now. */ 220 if (image->type != KEXEC_TYPE_DEFAULT) 221 return -EINVAL; 222 223 /* Get the destination where the assembler code should be copied to.*/ 224 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 225 226 /* Then copy it */ 227 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 228 return 0; 229 } 230 231 void machine_kexec_cleanup(struct kimage *image) 232 { 233 } 234 235 void arch_crash_save_vmcoreinfo(void) 236 { 237 VMCOREINFO_SYMBOL(lowcore_ptr); 238 VMCOREINFO_SYMBOL(high_memory); 239 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 240 } 241 242 void machine_shutdown(void) 243 { 244 } 245 246 void machine_crash_shutdown(struct pt_regs *regs) 247 { 248 } 249 250 /* 251 * Do normal kexec 252 */ 253 static void __do_machine_kexec(void *data) 254 { 255 relocate_kernel_t data_mover; 256 struct kimage *image = data; 257 258 s390_reset_system(); 259 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 260 261 /* Call the moving routine */ 262 (*data_mover)(&image->head, image->start); 263 264 /* Die if kexec returns */ 265 disabled_wait((unsigned long) __builtin_return_address(0)); 266 } 267 268 /* 269 * Reset system and call either kdump or normal kexec 270 */ 271 static void __machine_kexec(void *data) 272 { 273 __arch_local_irq_stosm(0x04); /* enable DAT */ 274 pfault_fini(); 275 tracing_off(); 276 debug_locks_off(); 277 #ifdef CONFIG_CRASH_DUMP 278 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 279 __machine_kdump(data); 280 #endif 281 __do_machine_kexec(data); 282 } 283 284 /* 285 * Do either kdump or normal kexec. In case of kdump we first ask 286 * purgatory, if kdump checksums are valid. 287 */ 288 void machine_kexec(struct kimage *image) 289 { 290 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 291 return; 292 tracer_disable(); 293 smp_send_stop(); 294 smp_call_ipl_cpu(__machine_kexec, image); 295 } 296