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/reset.h> 24 #include <asm/ipl.h> 25 #include <asm/diag.h> 26 #include <asm/elf.h> 27 #include <asm/asm-offsets.h> 28 #include <asm/cacheflush.h> 29 #include <asm/os_info.h> 30 #include <asm/set_memory.h> 31 #include <asm/switch_to.h> 32 #include <asm/nmi.h> 33 34 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long); 35 36 extern const unsigned char relocate_kernel[]; 37 extern const unsigned long long relocate_kernel_len; 38 39 #ifdef CONFIG_CRASH_DUMP 40 41 /* 42 * PM notifier callback for kdump 43 */ 44 static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action, 45 void *ptr) 46 { 47 switch (action) { 48 case PM_SUSPEND_PREPARE: 49 case PM_HIBERNATION_PREPARE: 50 if (kexec_crash_image) 51 arch_kexec_unprotect_crashkres(); 52 break; 53 case PM_POST_SUSPEND: 54 case PM_POST_HIBERNATION: 55 if (kexec_crash_image) 56 arch_kexec_protect_crashkres(); 57 break; 58 default: 59 return NOTIFY_DONE; 60 } 61 return NOTIFY_OK; 62 } 63 64 static int __init machine_kdump_pm_init(void) 65 { 66 pm_notifier(machine_kdump_pm_cb, 0); 67 return 0; 68 } 69 arch_initcall(machine_kdump_pm_init); 70 71 /* 72 * Reset the system, copy boot CPU registers to absolute zero, 73 * and jump to the kdump image 74 */ 75 static void __do_machine_kdump(void *image) 76 { 77 int (*start_kdump)(int); 78 unsigned long prefix; 79 80 /* store_status() saved the prefix register to lowcore */ 81 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 82 83 /* Now do the reset */ 84 s390_reset_system(); 85 86 /* 87 * Copy dump CPU store status info to absolute zero. 88 * This need to be done *after* s390_reset_system set the 89 * prefix register of this CPU to zero 90 */ 91 memcpy((void *) __LC_FPREGS_SAVE_AREA, 92 (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512); 93 94 __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); 95 start_kdump = (void *)((struct kimage *) image)->start; 96 start_kdump(1); 97 98 /* Die if start_kdump returns */ 99 disabled_wait((unsigned long) __builtin_return_address(0)); 100 } 101 102 /* 103 * Start kdump: create a LGR log entry, store status of all CPUs and 104 * branch to __do_machine_kdump. 105 */ 106 static noinline void __machine_kdump(void *image) 107 { 108 struct mcesa *mcesa; 109 unsigned long cr2_old, cr2_new; 110 int this_cpu, cpu; 111 112 lgr_info_log(); 113 /* Get status of the other CPUs */ 114 this_cpu = smp_find_processor_id(stap()); 115 for_each_online_cpu(cpu) { 116 if (cpu == this_cpu) 117 continue; 118 if (smp_store_status(cpu)) 119 continue; 120 } 121 /* Store status of the boot CPU */ 122 mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); 123 if (MACHINE_HAS_VX) 124 save_vx_regs((__vector128 *) mcesa->vector_save_area); 125 if (MACHINE_HAS_GS) { 126 __ctl_store(cr2_old, 2, 2); 127 cr2_new = cr2_old | (1UL << 4); 128 __ctl_load(cr2_new, 2, 2); 129 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 130 __ctl_load(cr2_old, 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 /* 146 * Check if kdump checksums are valid: We call purgatory with parameter "0" 147 */ 148 static int kdump_csum_valid(struct kimage *image) 149 { 150 #ifdef CONFIG_CRASH_DUMP 151 int (*start_kdump)(int) = (void *)image->start; 152 int rc; 153 154 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 155 rc = start_kdump(0); 156 __arch_local_irq_stosm(0x04); /* enable DAT */ 157 return rc ? 0 : -EINVAL; 158 #else 159 return -EINVAL; 160 #endif 161 } 162 163 #ifdef CONFIG_CRASH_DUMP 164 165 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 166 { 167 unsigned long addr, size; 168 169 for (addr = begin; addr < end; addr += PAGE_SIZE) 170 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 171 size = begin - crashk_res.start; 172 if (size) 173 os_info_crashkernel_add(crashk_res.start, size); 174 else 175 os_info_crashkernel_add(0, 0); 176 } 177 178 static void crash_protect_pages(int protect) 179 { 180 unsigned long size; 181 182 if (!crashk_res.end) 183 return; 184 size = resource_size(&crashk_res); 185 if (protect) 186 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 187 else 188 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 189 } 190 191 void arch_kexec_protect_crashkres(void) 192 { 193 crash_protect_pages(1); 194 } 195 196 void arch_kexec_unprotect_crashkres(void) 197 { 198 crash_protect_pages(0); 199 } 200 201 #endif 202 203 /* 204 * Give back memory to hypervisor before new kdump is loaded 205 */ 206 static int machine_kexec_prepare_kdump(void) 207 { 208 #ifdef CONFIG_CRASH_DUMP 209 if (MACHINE_IS_VM) 210 diag10_range(PFN_DOWN(crashk_res.start), 211 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 212 return 0; 213 #else 214 return -EINVAL; 215 #endif 216 } 217 218 int machine_kexec_prepare(struct kimage *image) 219 { 220 void *reboot_code_buffer; 221 222 /* Can't replace kernel image since it is read-only. */ 223 if (ipl_flags & IPL_NSS_VALID) 224 return -EOPNOTSUPP; 225 226 if (image->type == KEXEC_TYPE_CRASH) 227 return machine_kexec_prepare_kdump(); 228 229 /* We don't support anything but the default image type for now. */ 230 if (image->type != KEXEC_TYPE_DEFAULT) 231 return -EINVAL; 232 233 /* Get the destination where the assembler code should be copied to.*/ 234 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 235 236 /* Then copy it */ 237 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 238 return 0; 239 } 240 241 void machine_kexec_cleanup(struct kimage *image) 242 { 243 } 244 245 void arch_crash_save_vmcoreinfo(void) 246 { 247 VMCOREINFO_SYMBOL(lowcore_ptr); 248 VMCOREINFO_SYMBOL(high_memory); 249 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 250 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 251 } 252 253 void machine_shutdown(void) 254 { 255 } 256 257 void machine_crash_shutdown(struct pt_regs *regs) 258 { 259 } 260 261 /* 262 * Do normal kexec 263 */ 264 static void __do_machine_kexec(void *data) 265 { 266 relocate_kernel_t data_mover; 267 struct kimage *image = data; 268 269 s390_reset_system(); 270 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 271 272 /* Call the moving routine */ 273 (*data_mover)(&image->head, image->start); 274 275 /* Die if kexec returns */ 276 disabled_wait((unsigned long) __builtin_return_address(0)); 277 } 278 279 /* 280 * Reset system and call either kdump or normal kexec 281 */ 282 static void __machine_kexec(void *data) 283 { 284 __arch_local_irq_stosm(0x04); /* enable DAT */ 285 pfault_fini(); 286 tracing_off(); 287 debug_locks_off(); 288 #ifdef CONFIG_CRASH_DUMP 289 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 290 __machine_kdump(data); 291 #endif 292 __do_machine_kexec(data); 293 } 294 295 /* 296 * Do either kdump or normal kexec. In case of kdump we first ask 297 * purgatory, if kdump checksums are valid. 298 */ 299 void machine_kexec(struct kimage *image) 300 { 301 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 302 return; 303 tracer_disable(); 304 smp_send_stop(); 305 smp_call_ipl_cpu(__machine_kexec, image); 306 } 307