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/pgtable.h> 20 #include <asm/pgalloc.h> 21 #include <asm/smp.h> 22 #include <asm/ipl.h> 23 #include <asm/diag.h> 24 #include <asm/elf.h> 25 #include <asm/asm-offsets.h> 26 #include <asm/cacheflush.h> 27 #include <asm/os_info.h> 28 #include <asm/set_memory.h> 29 #include <asm/stacktrace.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 * Reset the system, copy boot CPU registers to absolute zero, 42 * and jump to the kdump image 43 */ 44 static void __do_machine_kdump(void *image) 45 { 46 int (*start_kdump)(int); 47 unsigned long prefix; 48 49 /* store_status() saved the prefix register to lowcore */ 50 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 51 52 /* Now do the reset */ 53 s390_reset_system(); 54 55 /* 56 * Copy dump CPU store status info to absolute zero. 57 * This need to be done *after* s390_reset_system set the 58 * prefix register of this CPU to zero 59 */ 60 memcpy((void *) __LC_FPREGS_SAVE_AREA, 61 (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512); 62 63 __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); 64 start_kdump = (void *)((struct kimage *) image)->start; 65 start_kdump(1); 66 67 /* Die if start_kdump returns */ 68 disabled_wait(); 69 } 70 71 /* 72 * Start kdump: create a LGR log entry, store status of all CPUs and 73 * branch to __do_machine_kdump. 74 */ 75 static noinline void __machine_kdump(void *image) 76 { 77 struct mcesa *mcesa; 78 union ctlreg2 cr2_old, cr2_new; 79 int this_cpu, cpu; 80 81 lgr_info_log(); 82 /* Get status of the other CPUs */ 83 this_cpu = smp_find_processor_id(stap()); 84 for_each_online_cpu(cpu) { 85 if (cpu == this_cpu) 86 continue; 87 if (smp_store_status(cpu)) 88 continue; 89 } 90 /* Store status of the boot CPU */ 91 mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); 92 if (MACHINE_HAS_VX) 93 save_vx_regs((__vector128 *) mcesa->vector_save_area); 94 if (MACHINE_HAS_GS) { 95 __ctl_store(cr2_old.val, 2, 2); 96 cr2_new = cr2_old; 97 cr2_new.gse = 1; 98 __ctl_load(cr2_new.val, 2, 2); 99 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 100 __ctl_load(cr2_old.val, 2, 2); 101 } 102 /* 103 * To create a good backchain for this CPU in the dump store_status 104 * is passed the address of a function. The address is saved into 105 * the PSW save area of the boot CPU and the function is invoked as 106 * a tail call of store_status. The backchain in the dump will look 107 * like this: 108 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 109 * The call to store_status() will not return. 110 */ 111 store_status(__do_machine_kdump, image); 112 } 113 114 static unsigned long do_start_kdump(unsigned long addr) 115 { 116 struct kimage *image = (struct kimage *) addr; 117 int (*start_kdump)(int) = (void *)image->start; 118 int rc; 119 120 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 121 rc = start_kdump(0); 122 __arch_local_irq_stosm(0x04); /* enable DAT */ 123 return rc; 124 } 125 126 #endif /* CONFIG_CRASH_DUMP */ 127 128 /* 129 * Check if kdump checksums are valid: We call purgatory with parameter "0" 130 */ 131 static bool kdump_csum_valid(struct kimage *image) 132 { 133 #ifdef CONFIG_CRASH_DUMP 134 int rc; 135 136 preempt_disable(); 137 rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image); 138 preempt_enable(); 139 return rc == 0; 140 #else 141 return false; 142 #endif 143 } 144 145 #ifdef CONFIG_CRASH_DUMP 146 147 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 148 { 149 unsigned long addr, size; 150 151 for (addr = begin; addr < end; addr += PAGE_SIZE) 152 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 153 size = begin - crashk_res.start; 154 if (size) 155 os_info_crashkernel_add(crashk_res.start, size); 156 else 157 os_info_crashkernel_add(0, 0); 158 } 159 160 static void crash_protect_pages(int protect) 161 { 162 unsigned long size; 163 164 if (!crashk_res.end) 165 return; 166 size = resource_size(&crashk_res); 167 if (protect) 168 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 169 else 170 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 171 } 172 173 void arch_kexec_protect_crashkres(void) 174 { 175 crash_protect_pages(1); 176 } 177 178 void arch_kexec_unprotect_crashkres(void) 179 { 180 crash_protect_pages(0); 181 } 182 183 #endif 184 185 /* 186 * Give back memory to hypervisor before new kdump is loaded 187 */ 188 static int machine_kexec_prepare_kdump(void) 189 { 190 #ifdef CONFIG_CRASH_DUMP 191 if (MACHINE_IS_VM) 192 diag10_range(PFN_DOWN(crashk_res.start), 193 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 194 return 0; 195 #else 196 return -EINVAL; 197 #endif 198 } 199 200 int machine_kexec_prepare(struct kimage *image) 201 { 202 void *reboot_code_buffer; 203 204 if (image->type == KEXEC_TYPE_CRASH) 205 return machine_kexec_prepare_kdump(); 206 207 /* We don't support anything but the default image type for now. */ 208 if (image->type != KEXEC_TYPE_DEFAULT) 209 return -EINVAL; 210 211 /* Get the destination where the assembler code should be copied to.*/ 212 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 213 214 /* Then copy it */ 215 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 216 return 0; 217 } 218 219 void machine_kexec_cleanup(struct kimage *image) 220 { 221 } 222 223 void arch_crash_save_vmcoreinfo(void) 224 { 225 VMCOREINFO_SYMBOL(lowcore_ptr); 226 VMCOREINFO_SYMBOL(high_memory); 227 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 228 vmcoreinfo_append_str("SDMA=%lx\n", __sdma); 229 vmcoreinfo_append_str("EDMA=%lx\n", __edma); 230 vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); 231 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 232 } 233 234 void machine_shutdown(void) 235 { 236 } 237 238 void machine_crash_shutdown(struct pt_regs *regs) 239 { 240 set_os_info_reipl_block(); 241 } 242 243 /* 244 * Do normal kexec 245 */ 246 static void __do_machine_kexec(void *data) 247 { 248 relocate_kernel_t data_mover; 249 struct kimage *image = data; 250 251 s390_reset_system(); 252 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 253 254 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */ 255 /* Call the moving routine */ 256 (*data_mover)(&image->head, image->start); 257 258 /* Die if kexec returns */ 259 disabled_wait(); 260 } 261 262 /* 263 * Reset system and call either kdump or normal kexec 264 */ 265 static void __machine_kexec(void *data) 266 { 267 __arch_local_irq_stosm(0x04); /* enable DAT */ 268 pfault_fini(); 269 tracing_off(); 270 debug_locks_off(); 271 #ifdef CONFIG_CRASH_DUMP 272 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 273 __machine_kdump(data); 274 #endif 275 __do_machine_kexec(data); 276 } 277 278 /* 279 * Do either kdump or normal kexec. In case of kdump we first ask 280 * purgatory, if kdump checksums are valid. 281 */ 282 void machine_kexec(struct kimage *image) 283 { 284 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 285 return; 286 tracer_disable(); 287 smp_send_stop(); 288 smp_call_ipl_cpu(__machine_kexec, image); 289 } 290