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 /* 146 * Check if kdump checksums are valid: We call purgatory with parameter "0" 147 */ 148 static bool 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; 158 #else 159 return false; 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 if (image->type == KEXEC_TYPE_CRASH) 223 return machine_kexec_prepare_kdump(); 224 225 /* We don't support anything but the default image type for now. */ 226 if (image->type != KEXEC_TYPE_DEFAULT) 227 return -EINVAL; 228 229 /* Get the destination where the assembler code should be copied to.*/ 230 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 231 232 /* Then copy it */ 233 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 234 return 0; 235 } 236 237 void machine_kexec_cleanup(struct kimage *image) 238 { 239 } 240 241 void arch_crash_save_vmcoreinfo(void) 242 { 243 VMCOREINFO_SYMBOL(lowcore_ptr); 244 VMCOREINFO_SYMBOL(high_memory); 245 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 246 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 247 } 248 249 void machine_shutdown(void) 250 { 251 } 252 253 void machine_crash_shutdown(struct pt_regs *regs) 254 { 255 set_os_info_reipl_block(); 256 } 257 258 /* 259 * Do normal kexec 260 */ 261 static void __do_machine_kexec(void *data) 262 { 263 relocate_kernel_t data_mover; 264 struct kimage *image = data; 265 266 s390_reset_system(); 267 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 268 269 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */ 270 /* Call the moving routine */ 271 (*data_mover)(&image->head, image->start); 272 273 /* Die if kexec returns */ 274 disabled_wait((unsigned long) __builtin_return_address(0)); 275 } 276 277 /* 278 * Reset system and call either kdump or normal kexec 279 */ 280 static void __machine_kexec(void *data) 281 { 282 __arch_local_irq_stosm(0x04); /* enable DAT */ 283 pfault_fini(); 284 tracing_off(); 285 debug_locks_off(); 286 #ifdef CONFIG_CRASH_DUMP 287 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 288 __machine_kdump(data); 289 #endif 290 __do_machine_kexec(data); 291 } 292 293 /* 294 * Do either kdump or normal kexec. In case of kdump we first ask 295 * purgatory, if kdump checksums are valid. 296 */ 297 void machine_kexec(struct kimage *image) 298 { 299 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 300 return; 301 tracer_disable(); 302 smp_send_stop(); 303 smp_call_ipl_cpu(__machine_kexec, image); 304 } 305