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/stacktrace.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(); 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 } 144 145 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 #endif /* CONFIG_CRASH_DUMP */ 158 159 /* 160 * Check if kdump checksums are valid: We call purgatory with parameter "0" 161 */ 162 static bool kdump_csum_valid(struct kimage *image) 163 { 164 #ifdef CONFIG_CRASH_DUMP 165 int rc; 166 167 preempt_disable(); 168 rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image); 169 preempt_enable(); 170 return rc == 0; 171 #else 172 return false; 173 #endif 174 } 175 176 #ifdef CONFIG_CRASH_DUMP 177 178 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 179 { 180 unsigned long addr, size; 181 182 for (addr = begin; addr < end; addr += PAGE_SIZE) 183 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 184 size = begin - crashk_res.start; 185 if (size) 186 os_info_crashkernel_add(crashk_res.start, size); 187 else 188 os_info_crashkernel_add(0, 0); 189 } 190 191 static void crash_protect_pages(int protect) 192 { 193 unsigned long size; 194 195 if (!crashk_res.end) 196 return; 197 size = resource_size(&crashk_res); 198 if (protect) 199 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 200 else 201 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 202 } 203 204 void arch_kexec_protect_crashkres(void) 205 { 206 crash_protect_pages(1); 207 } 208 209 void arch_kexec_unprotect_crashkres(void) 210 { 211 crash_protect_pages(0); 212 } 213 214 #endif 215 216 /* 217 * Give back memory to hypervisor before new kdump is loaded 218 */ 219 static int machine_kexec_prepare_kdump(void) 220 { 221 #ifdef CONFIG_CRASH_DUMP 222 if (MACHINE_IS_VM) 223 diag10_range(PFN_DOWN(crashk_res.start), 224 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 225 return 0; 226 #else 227 return -EINVAL; 228 #endif 229 } 230 231 int machine_kexec_prepare(struct kimage *image) 232 { 233 void *reboot_code_buffer; 234 235 if (image->type == KEXEC_TYPE_CRASH) 236 return machine_kexec_prepare_kdump(); 237 238 /* We don't support anything but the default image type for now. */ 239 if (image->type != KEXEC_TYPE_DEFAULT) 240 return -EINVAL; 241 242 /* Get the destination where the assembler code should be copied to.*/ 243 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 244 245 /* Then copy it */ 246 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 247 return 0; 248 } 249 250 void machine_kexec_cleanup(struct kimage *image) 251 { 252 } 253 254 void arch_crash_save_vmcoreinfo(void) 255 { 256 VMCOREINFO_SYMBOL(lowcore_ptr); 257 VMCOREINFO_SYMBOL(high_memory); 258 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 259 vmcoreinfo_append_str("SDMA=%lx\n", __sdma); 260 vmcoreinfo_append_str("EDMA=%lx\n", __edma); 261 vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); 262 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 263 } 264 265 void machine_shutdown(void) 266 { 267 } 268 269 void machine_crash_shutdown(struct pt_regs *regs) 270 { 271 set_os_info_reipl_block(); 272 } 273 274 /* 275 * Do normal kexec 276 */ 277 static void __do_machine_kexec(void *data) 278 { 279 relocate_kernel_t data_mover; 280 struct kimage *image = data; 281 282 s390_reset_system(); 283 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 284 285 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */ 286 /* Call the moving routine */ 287 (*data_mover)(&image->head, image->start); 288 289 /* Die if kexec returns */ 290 disabled_wait(); 291 } 292 293 /* 294 * Reset system and call either kdump or normal kexec 295 */ 296 static void __machine_kexec(void *data) 297 { 298 __arch_local_irq_stosm(0x04); /* enable DAT */ 299 pfault_fini(); 300 tracing_off(); 301 debug_locks_off(); 302 #ifdef CONFIG_CRASH_DUMP 303 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 304 __machine_kdump(data); 305 #endif 306 __do_machine_kexec(data); 307 } 308 309 /* 310 * Do either kdump or normal kexec. In case of kdump we first ask 311 * purgatory, if kdump checksums are valid. 312 */ 313 void machine_kexec(struct kimage *image) 314 { 315 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 316 return; 317 tracer_disable(); 318 smp_send_stop(); 319 smp_call_ipl_cpu(__machine_kexec, image); 320 } 321