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 <asm/cio.h> 18 #include <asm/setup.h> 19 #include <asm/smp.h> 20 #include <asm/ipl.h> 21 #include <asm/diag.h> 22 #include <asm/elf.h> 23 #include <asm/asm-offsets.h> 24 #include <asm/cacheflush.h> 25 #include <asm/os_info.h> 26 #include <asm/set_memory.h> 27 #include <asm/stacktrace.h> 28 #include <asm/switch_to.h> 29 #include <asm/nmi.h> 30 31 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long); 32 33 extern const unsigned char relocate_kernel[]; 34 extern const unsigned long long relocate_kernel_len; 35 36 #ifdef CONFIG_CRASH_DUMP 37 38 /* 39 * Reset the system, copy boot CPU registers to absolute zero, 40 * and jump to the kdump image 41 */ 42 static void __do_machine_kdump(void *image) 43 { 44 int (*start_kdump)(int); 45 unsigned long prefix; 46 47 /* store_status() saved the prefix register to lowcore */ 48 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 49 50 /* Now do the reset */ 51 s390_reset_system(); 52 53 /* 54 * Copy dump CPU store status info to absolute zero. 55 * This need to be done *after* s390_reset_system set the 56 * prefix register of this CPU to zero 57 */ 58 memcpy((void *) __LC_FPREGS_SAVE_AREA, 59 (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512); 60 61 __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); 62 start_kdump = (void *)((struct kimage *) image)->start; 63 start_kdump(1); 64 65 /* Die if start_kdump returns */ 66 disabled_wait(); 67 } 68 69 /* 70 * Start kdump: create a LGR log entry, store status of all CPUs and 71 * branch to __do_machine_kdump. 72 */ 73 static noinline void __machine_kdump(void *image) 74 { 75 struct mcesa *mcesa; 76 union ctlreg2 cr2_old, cr2_new; 77 int this_cpu, cpu; 78 79 lgr_info_log(); 80 /* Get status of the other CPUs */ 81 this_cpu = smp_find_processor_id(stap()); 82 for_each_online_cpu(cpu) { 83 if (cpu == this_cpu) 84 continue; 85 if (smp_store_status(cpu)) 86 continue; 87 } 88 /* Store status of the boot CPU */ 89 mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); 90 if (MACHINE_HAS_VX) 91 save_vx_regs((__vector128 *) mcesa->vector_save_area); 92 if (MACHINE_HAS_GS) { 93 __ctl_store(cr2_old.val, 2, 2); 94 cr2_new = cr2_old; 95 cr2_new.gse = 1; 96 __ctl_load(cr2_new.val, 2, 2); 97 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 98 __ctl_load(cr2_old.val, 2, 2); 99 } 100 /* 101 * To create a good backchain for this CPU in the dump store_status 102 * is passed the address of a function. The address is saved into 103 * the PSW save area of the boot CPU and the function is invoked as 104 * a tail call of store_status. The backchain in the dump will look 105 * like this: 106 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 107 * The call to store_status() will not return. 108 */ 109 store_status(__do_machine_kdump, image); 110 } 111 112 static unsigned long do_start_kdump(unsigned long addr) 113 { 114 struct kimage *image = (struct kimage *) addr; 115 int (*start_kdump)(int) = (void *)image->start; 116 int rc; 117 118 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 119 rc = start_kdump(0); 120 __arch_local_irq_stosm(0x04); /* enable DAT */ 121 return rc; 122 } 123 124 #endif /* CONFIG_CRASH_DUMP */ 125 126 /* 127 * Check if kdump checksums are valid: We call purgatory with parameter "0" 128 */ 129 static bool kdump_csum_valid(struct kimage *image) 130 { 131 #ifdef CONFIG_CRASH_DUMP 132 int rc; 133 134 preempt_disable(); 135 rc = call_on_stack(1, S390_lowcore.nodat_stack, unsigned long, do_start_kdump, 136 unsigned long, (unsigned long)image); 137 preempt_enable(); 138 return rc == 0; 139 #else 140 return false; 141 #endif 142 } 143 144 #ifdef CONFIG_CRASH_DUMP 145 146 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 147 { 148 unsigned long addr, size; 149 150 for (addr = begin; addr < end; addr += PAGE_SIZE) 151 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 152 size = begin - crashk_res.start; 153 if (size) 154 os_info_crashkernel_add(crashk_res.start, size); 155 else 156 os_info_crashkernel_add(0, 0); 157 } 158 159 static void crash_protect_pages(int protect) 160 { 161 unsigned long size; 162 163 if (!crashk_res.end) 164 return; 165 size = resource_size(&crashk_res); 166 if (protect) 167 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 168 else 169 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 170 } 171 172 void arch_kexec_protect_crashkres(void) 173 { 174 crash_protect_pages(1); 175 } 176 177 void arch_kexec_unprotect_crashkres(void) 178 { 179 crash_protect_pages(0); 180 } 181 182 #endif 183 184 /* 185 * Give back memory to hypervisor before new kdump is loaded 186 */ 187 static int machine_kexec_prepare_kdump(void) 188 { 189 #ifdef CONFIG_CRASH_DUMP 190 if (MACHINE_IS_VM) 191 diag10_range(PFN_DOWN(crashk_res.start), 192 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 193 return 0; 194 #else 195 return -EINVAL; 196 #endif 197 } 198 199 int machine_kexec_prepare(struct kimage *image) 200 { 201 void *reboot_code_buffer; 202 203 if (image->type == KEXEC_TYPE_CRASH) 204 return machine_kexec_prepare_kdump(); 205 206 /* We don't support anything but the default image type for now. */ 207 if (image->type != KEXEC_TYPE_DEFAULT) 208 return -EINVAL; 209 210 /* Get the destination where the assembler code should be copied to.*/ 211 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 212 213 /* Then copy it */ 214 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 215 return 0; 216 } 217 218 void machine_kexec_cleanup(struct kimage *image) 219 { 220 } 221 222 void arch_crash_save_vmcoreinfo(void) 223 { 224 VMCOREINFO_SYMBOL(lowcore_ptr); 225 VMCOREINFO_SYMBOL(high_memory); 226 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 227 vmcoreinfo_append_str("SAMODE31=%lx\n", __samode31); 228 vmcoreinfo_append_str("EAMODE31=%lx\n", __eamode31); 229 vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); 230 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 231 } 232 233 void machine_shutdown(void) 234 { 235 } 236 237 void machine_crash_shutdown(struct pt_regs *regs) 238 { 239 set_os_info_reipl_block(); 240 } 241 242 /* 243 * Do normal kexec 244 */ 245 static void __do_machine_kexec(void *data) 246 { 247 relocate_kernel_t data_mover; 248 struct kimage *image = data; 249 250 s390_reset_system(); 251 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 252 253 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */ 254 /* Call the moving routine */ 255 (*data_mover)(&image->head, image->start); 256 257 /* Die if kexec returns */ 258 disabled_wait(); 259 } 260 261 /* 262 * Reset system and call either kdump or normal kexec 263 */ 264 static void __machine_kexec(void *data) 265 { 266 pfault_fini(); 267 tracing_off(); 268 debug_locks_off(); 269 #ifdef CONFIG_CRASH_DUMP 270 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 271 __machine_kdump(data); 272 #endif 273 __do_machine_kexec(data); 274 } 275 276 /* 277 * Do either kdump or normal kexec. In case of kdump we first ask 278 * purgatory, if kdump checksums are valid. 279 */ 280 void machine_kexec(struct kimage *image) 281 { 282 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 283 return; 284 tracer_disable(); 285 smp_send_stop(); 286 smp_call_ipl_cpu(__machine_kexec, image); 287 } 288