1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2005, 2011 4 * 5 * Author(s): Rolf Adelsberger, 6 * Michael Holzheu <holzheu@linux.vnet.ibm.com> 7 */ 8 9 #include <linux/device.h> 10 #include <linux/mm.h> 11 #include <linux/kexec.h> 12 #include <linux/delay.h> 13 #include <linux/reboot.h> 14 #include <linux/ftrace.h> 15 #include <linux/debug_locks.h> 16 #include <asm/cio.h> 17 #include <asm/setup.h> 18 #include <asm/smp.h> 19 #include <asm/ipl.h> 20 #include <asm/diag.h> 21 #include <asm/elf.h> 22 #include <asm/asm-offsets.h> 23 #include <asm/cacheflush.h> 24 #include <asm/os_info.h> 25 #include <asm/set_memory.h> 26 #include <asm/stacktrace.h> 27 #include <asm/switch_to.h> 28 #include <asm/nmi.h> 29 30 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long); 31 32 extern const unsigned char relocate_kernel[]; 33 extern const unsigned long long relocate_kernel_len; 34 35 #ifdef CONFIG_CRASH_DUMP 36 37 /* 38 * Reset the system, copy boot CPU registers to absolute zero, 39 * and jump to the kdump image 40 */ 41 static void __do_machine_kdump(void *image) 42 { 43 int (*start_kdump)(int); 44 unsigned long prefix; 45 46 /* store_status() saved the prefix register to lowcore */ 47 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 48 49 /* Now do the reset */ 50 s390_reset_system(); 51 52 /* 53 * Copy dump CPU store status info to absolute zero. 54 * This need to be done *after* s390_reset_system set the 55 * prefix register of this CPU to zero 56 */ 57 memcpy((void *) __LC_FPREGS_SAVE_AREA, 58 (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512); 59 60 __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); 61 start_kdump = (void *)((struct kimage *) image)->start; 62 start_kdump(1); 63 64 /* Die if start_kdump returns */ 65 disabled_wait(); 66 } 67 68 /* 69 * Start kdump: create a LGR log entry, store status of all CPUs and 70 * branch to __do_machine_kdump. 71 */ 72 static noinline void __machine_kdump(void *image) 73 { 74 struct mcesa *mcesa; 75 union ctlreg2 cr2_old, cr2_new; 76 int this_cpu, cpu; 77 78 lgr_info_log(); 79 /* Get status of the other CPUs */ 80 this_cpu = smp_find_processor_id(stap()); 81 for_each_online_cpu(cpu) { 82 if (cpu == this_cpu) 83 continue; 84 if (smp_store_status(cpu)) 85 continue; 86 } 87 /* Store status of the boot CPU */ 88 mcesa = __va(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); 89 if (MACHINE_HAS_VX) 90 save_vx_regs((__vector128 *) mcesa->vector_save_area); 91 if (MACHINE_HAS_GS) { 92 __ctl_store(cr2_old.val, 2, 2); 93 cr2_new = cr2_old; 94 cr2_new.gse = 1; 95 __ctl_load(cr2_new.val, 2, 2); 96 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 97 __ctl_load(cr2_old.val, 2, 2); 98 } 99 /* 100 * To create a good backchain for this CPU in the dump store_status 101 * is passed the address of a function. The address is saved into 102 * the PSW save area of the boot CPU and the function is invoked as 103 * a tail call of store_status. The backchain in the dump will look 104 * like this: 105 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 106 * The call to store_status() will not return. 107 */ 108 store_status(__do_machine_kdump, image); 109 } 110 111 static unsigned long do_start_kdump(unsigned long addr) 112 { 113 struct kimage *image = (struct kimage *) addr; 114 int (*start_kdump)(int) = (void *)image->start; 115 int rc; 116 117 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 118 rc = start_kdump(0); 119 __arch_local_irq_stosm(0x04); /* enable DAT */ 120 return rc; 121 } 122 123 #endif /* CONFIG_CRASH_DUMP */ 124 125 /* 126 * Check if kdump checksums are valid: We call purgatory with parameter "0" 127 */ 128 static bool kdump_csum_valid(struct kimage *image) 129 { 130 #ifdef CONFIG_CRASH_DUMP 131 int rc; 132 133 preempt_disable(); 134 rc = call_on_stack(1, S390_lowcore.nodat_stack, unsigned long, do_start_kdump, 135 unsigned long, (unsigned long)image); 136 preempt_enable(); 137 return rc == 0; 138 #else 139 return false; 140 #endif 141 } 142 143 #ifdef CONFIG_CRASH_DUMP 144 145 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 146 { 147 unsigned long addr, size; 148 149 for (addr = begin; addr < end; addr += PAGE_SIZE) 150 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 151 size = begin - crashk_res.start; 152 if (size) 153 os_info_crashkernel_add(crashk_res.start, size); 154 else 155 os_info_crashkernel_add(0, 0); 156 } 157 158 static void crash_protect_pages(int protect) 159 { 160 unsigned long size; 161 162 if (!crashk_res.end) 163 return; 164 size = resource_size(&crashk_res); 165 if (protect) 166 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 167 else 168 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 169 } 170 171 void arch_kexec_protect_crashkres(void) 172 { 173 crash_protect_pages(1); 174 } 175 176 void arch_kexec_unprotect_crashkres(void) 177 { 178 crash_protect_pages(0); 179 } 180 181 #endif 182 183 /* 184 * Give back memory to hypervisor before new kdump is loaded 185 */ 186 static int machine_kexec_prepare_kdump(void) 187 { 188 #ifdef CONFIG_CRASH_DUMP 189 if (MACHINE_IS_VM) 190 diag10_range(PFN_DOWN(crashk_res.start), 191 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 192 return 0; 193 #else 194 return -EINVAL; 195 #endif 196 } 197 198 int machine_kexec_prepare(struct kimage *image) 199 { 200 void *reboot_code_buffer; 201 202 if (image->type == KEXEC_TYPE_CRASH) 203 return machine_kexec_prepare_kdump(); 204 205 /* We don't support anything but the default image type for now. */ 206 if (image->type != KEXEC_TYPE_DEFAULT) 207 return -EINVAL; 208 209 /* Get the destination where the assembler code should be copied to.*/ 210 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 211 212 /* Then copy it */ 213 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 214 return 0; 215 } 216 217 void machine_kexec_cleanup(struct kimage *image) 218 { 219 } 220 221 void arch_crash_save_vmcoreinfo(void) 222 { 223 VMCOREINFO_SYMBOL(lowcore_ptr); 224 VMCOREINFO_SYMBOL(high_memory); 225 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 226 vmcoreinfo_append_str("SAMODE31=%lx\n", __samode31); 227 vmcoreinfo_append_str("EAMODE31=%lx\n", __eamode31); 228 vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); 229 put_abs_lowcore(vmcore_info, paddr_vmcoreinfo_note()); 230 } 231 232 void machine_shutdown(void) 233 { 234 } 235 236 void machine_crash_shutdown(struct pt_regs *regs) 237 { 238 set_os_info_reipl_block(); 239 } 240 241 /* 242 * Do normal kexec 243 */ 244 static void __do_machine_kexec(void *data) 245 { 246 relocate_kernel_t data_mover; 247 struct kimage *image = data; 248 249 s390_reset_system(); 250 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 251 252 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */ 253 /* Call the moving routine */ 254 (*data_mover)(&image->head, image->start); 255 256 /* Die if kexec returns */ 257 disabled_wait(); 258 } 259 260 /* 261 * Reset system and call either kdump or normal kexec 262 */ 263 static void __machine_kexec(void *data) 264 { 265 pfault_fini(); 266 tracing_off(); 267 debug_locks_off(); 268 #ifdef CONFIG_CRASH_DUMP 269 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 270 __machine_kdump(data); 271 #endif 272 __do_machine_kexec(data); 273 } 274 275 /* 276 * Do either kdump or normal kexec. In case of kdump we first ask 277 * purgatory, if kdump checksums are valid. 278 */ 279 void machine_kexec(struct kimage *image) 280 { 281 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 282 return; 283 tracer_disable(); 284 smp_send_stop(); 285 smp_call_ipl_cpu(__machine_kexec, image); 286 } 287