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 static unsigned long do_start_kdump(unsigned long addr) 146 { 147 struct kimage *image = (struct kimage *) addr; 148 int (*start_kdump)(int) = (void *)image->start; 149 int rc; 150 151 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 152 rc = start_kdump(0); 153 __arch_local_irq_stosm(0x04); /* enable DAT */ 154 return rc; 155 } 156 157 /* 158 * Check if kdump checksums are valid: We call purgatory with parameter "0" 159 */ 160 static bool kdump_csum_valid(struct kimage *image) 161 { 162 #ifdef CONFIG_CRASH_DUMP 163 int rc; 164 165 rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image); 166 return rc == 0; 167 #else 168 return false; 169 #endif 170 } 171 172 #ifdef CONFIG_CRASH_DUMP 173 174 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 175 { 176 unsigned long addr, size; 177 178 for (addr = begin; addr < end; addr += PAGE_SIZE) 179 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 180 size = begin - crashk_res.start; 181 if (size) 182 os_info_crashkernel_add(crashk_res.start, size); 183 else 184 os_info_crashkernel_add(0, 0); 185 } 186 187 static void crash_protect_pages(int protect) 188 { 189 unsigned long size; 190 191 if (!crashk_res.end) 192 return; 193 size = resource_size(&crashk_res); 194 if (protect) 195 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 196 else 197 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 198 } 199 200 void arch_kexec_protect_crashkres(void) 201 { 202 crash_protect_pages(1); 203 } 204 205 void arch_kexec_unprotect_crashkres(void) 206 { 207 crash_protect_pages(0); 208 } 209 210 #endif 211 212 /* 213 * Give back memory to hypervisor before new kdump is loaded 214 */ 215 static int machine_kexec_prepare_kdump(void) 216 { 217 #ifdef CONFIG_CRASH_DUMP 218 if (MACHINE_IS_VM) 219 diag10_range(PFN_DOWN(crashk_res.start), 220 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 221 return 0; 222 #else 223 return -EINVAL; 224 #endif 225 } 226 227 int machine_kexec_prepare(struct kimage *image) 228 { 229 void *reboot_code_buffer; 230 231 if (image->type == KEXEC_TYPE_CRASH) 232 return machine_kexec_prepare_kdump(); 233 234 /* We don't support anything but the default image type for now. */ 235 if (image->type != KEXEC_TYPE_DEFAULT) 236 return -EINVAL; 237 238 /* Get the destination where the assembler code should be copied to.*/ 239 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 240 241 /* Then copy it */ 242 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 243 return 0; 244 } 245 246 void machine_kexec_cleanup(struct kimage *image) 247 { 248 } 249 250 void arch_crash_save_vmcoreinfo(void) 251 { 252 VMCOREINFO_SYMBOL(lowcore_ptr); 253 VMCOREINFO_SYMBOL(high_memory); 254 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 255 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 256 } 257 258 void machine_shutdown(void) 259 { 260 } 261 262 void machine_crash_shutdown(struct pt_regs *regs) 263 { 264 set_os_info_reipl_block(); 265 } 266 267 /* 268 * Do normal kexec 269 */ 270 static void __do_machine_kexec(void *data) 271 { 272 relocate_kernel_t data_mover; 273 struct kimage *image = data; 274 275 s390_reset_system(); 276 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 277 278 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */ 279 /* Call the moving routine */ 280 (*data_mover)(&image->head, image->start); 281 282 /* Die if kexec returns */ 283 disabled_wait((unsigned long) __builtin_return_address(0)); 284 } 285 286 /* 287 * Reset system and call either kdump or normal kexec 288 */ 289 static void __machine_kexec(void *data) 290 { 291 __arch_local_irq_stosm(0x04); /* enable DAT */ 292 pfault_fini(); 293 tracing_off(); 294 debug_locks_off(); 295 #ifdef CONFIG_CRASH_DUMP 296 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 297 __machine_kdump(data); 298 #endif 299 __do_machine_kexec(data); 300 } 301 302 /* 303 * Do either kdump or normal kexec. In case of kdump we first ask 304 * purgatory, if kdump checksums are valid. 305 */ 306 void machine_kexec(struct kimage *image) 307 { 308 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 309 return; 310 tracer_disable(); 311 smp_send_stop(); 312 smp_call_ipl_cpu(__machine_kexec, image); 313 } 314