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 union ctlreg2 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.val, 2, 2); 127 cr2_new = cr2_old; 128 cr2_new.gse = 1; 129 __ctl_load(cr2_new.val, 2, 2); 130 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 131 __ctl_load(cr2_old.val, 2, 2); 132 } 133 /* 134 * To create a good backchain for this CPU in the dump store_status 135 * is passed the address of a function. The address is saved into 136 * the PSW save area of the boot CPU and the function is invoked as 137 * a tail call of store_status. The backchain in the dump will look 138 * like this: 139 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 140 * The call to store_status() will not return. 141 */ 142 store_status(__do_machine_kdump, image); 143 } 144 #endif 145 146 /* 147 * Check if kdump checksums are valid: We call purgatory with parameter "0" 148 */ 149 static bool kdump_csum_valid(struct kimage *image) 150 { 151 #ifdef CONFIG_CRASH_DUMP 152 int (*start_kdump)(int) = (void *)image->start; 153 int rc; 154 155 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 156 rc = start_kdump(0); 157 __arch_local_irq_stosm(0x04); /* enable DAT */ 158 return rc == 0; 159 #else 160 return false; 161 #endif 162 } 163 164 #ifdef CONFIG_CRASH_DUMP 165 166 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 167 { 168 unsigned long addr, size; 169 170 for (addr = begin; addr < end; addr += PAGE_SIZE) 171 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 172 size = begin - crashk_res.start; 173 if (size) 174 os_info_crashkernel_add(crashk_res.start, size); 175 else 176 os_info_crashkernel_add(0, 0); 177 } 178 179 static void crash_protect_pages(int protect) 180 { 181 unsigned long size; 182 183 if (!crashk_res.end) 184 return; 185 size = resource_size(&crashk_res); 186 if (protect) 187 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 188 else 189 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 190 } 191 192 void arch_kexec_protect_crashkres(void) 193 { 194 crash_protect_pages(1); 195 } 196 197 void arch_kexec_unprotect_crashkres(void) 198 { 199 crash_protect_pages(0); 200 } 201 202 #endif 203 204 /* 205 * Give back memory to hypervisor before new kdump is loaded 206 */ 207 static int machine_kexec_prepare_kdump(void) 208 { 209 #ifdef CONFIG_CRASH_DUMP 210 if (MACHINE_IS_VM) 211 diag10_range(PFN_DOWN(crashk_res.start), 212 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 213 return 0; 214 #else 215 return -EINVAL; 216 #endif 217 } 218 219 int machine_kexec_prepare(struct kimage *image) 220 { 221 void *reboot_code_buffer; 222 223 if (image->type == KEXEC_TYPE_CRASH) 224 return machine_kexec_prepare_kdump(); 225 226 /* We don't support anything but the default image type for now. */ 227 if (image->type != KEXEC_TYPE_DEFAULT) 228 return -EINVAL; 229 230 /* Get the destination where the assembler code should be copied to.*/ 231 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 232 233 /* Then copy it */ 234 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 235 return 0; 236 } 237 238 void machine_kexec_cleanup(struct kimage *image) 239 { 240 } 241 242 void arch_crash_save_vmcoreinfo(void) 243 { 244 VMCOREINFO_SYMBOL(lowcore_ptr); 245 VMCOREINFO_SYMBOL(high_memory); 246 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 247 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 248 } 249 250 void machine_shutdown(void) 251 { 252 } 253 254 void machine_crash_shutdown(struct pt_regs *regs) 255 { 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