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/guarded_storage.h> 17#include <asm/pfault.h> 18#include <asm/cio.h> 19#include <asm/fpu.h> 20#include <asm/setup.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/abs_lowcore.h> 28#include <asm/os_info.h> 29#include <asm/set_memory.h> 30#include <asm/stacktrace.h> 31#include <asm/nmi.h> 32#include <asm/sclp.h> 33 34typedef void (*relocate_kernel_t)(unsigned long, unsigned long, unsigned long); 35typedef int (*purgatory_t)(int); 36 37extern const unsigned char relocate_kernel[]; 38extern const unsigned long long relocate_kernel_len; 39 40#ifdef CONFIG_CRASH_DUMP 41 42/* 43 * Reset the system, copy boot CPU registers to absolute zero, 44 * and jump to the kdump image 45 */ 46static void __do_machine_kdump(void *data) 47{ 48 struct kimage *image = data; 49 purgatory_t purgatory; 50 unsigned long prefix; 51 52 purgatory = (purgatory_t)image->start; 53 54 /* store_status() saved the prefix register to lowcore */ 55 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 56 57 /* Now do the reset */ 58 s390_reset_system(); 59 60 /* 61 * Copy dump CPU store status info to absolute zero. 62 * This need to be done *after* s390_reset_system set the 63 * prefix register of this CPU to zero 64 */ 65 memcpy(absolute_pointer(__LC_FPREGS_SAVE_AREA), 66 phys_to_virt(prefix + __LC_FPREGS_SAVE_AREA), 512); 67 68 call_nodat(1, int, purgatory, int, 1); 69 70 /* Die if kdump returns */ 71 disabled_wait(); 72} 73 74/* 75 * Start kdump: create a LGR log entry, store status of all CPUs and 76 * branch to __do_machine_kdump. 77 */ 78static noinline void __machine_kdump(void *image) 79{ 80 struct mcesa *mcesa; 81 union ctlreg2 cr2_old, cr2_new; 82 int this_cpu, cpu; 83 84 lgr_info_log(); 85 /* Get status of the other CPUs */ 86 this_cpu = smp_find_processor_id(stap()); 87 for_each_online_cpu(cpu) { 88 if (cpu == this_cpu) 89 continue; 90 if (smp_store_status(cpu)) 91 continue; 92 } 93 /* Store status of the boot CPU */ 94 mcesa = __va(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); 95 if (cpu_has_vx()) 96 save_vx_regs((__vector128 *) mcesa->vector_save_area); 97 if (MACHINE_HAS_GS) { 98 local_ctl_store(2, &cr2_old.reg); 99 cr2_new = cr2_old; 100 cr2_new.gse = 1; 101 local_ctl_load(2, &cr2_new.reg); 102 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 103 local_ctl_load(2, &cr2_old.reg); 104 } 105 /* 106 * To create a good backchain for this CPU in the dump store_status 107 * is passed the address of a function. The address is saved into 108 * the PSW save area of the boot CPU and the function is invoked as 109 * a tail call of store_status. The backchain in the dump will look 110 * like this: 111 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 112 * The call to store_status() will not return. 113 */ 114 store_status(__do_machine_kdump, image); 115} 116 117#endif /* CONFIG_CRASH_DUMP */ 118 119/* 120 * Check if kdump checksums are valid: We call purgatory with parameter "0" 121 */ 122static bool kdump_csum_valid(struct kimage *image) 123{ 124#ifdef CONFIG_CRASH_DUMP 125 purgatory_t purgatory = (purgatory_t)image->start; 126 int rc; 127 128 rc = call_nodat(1, int, purgatory, int, 0); 129 return rc == 0; 130#else 131 return false; 132#endif 133} 134 135#ifdef CONFIG_CRASH_DUMP 136 137void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 138{ 139 unsigned long addr, size; 140 141 for (addr = begin; addr < end; addr += PAGE_SIZE) 142 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 143 size = begin - crashk_res.start; 144 if (size) 145 os_info_crashkernel_add(crashk_res.start, size); 146 else 147 os_info_crashkernel_add(0, 0); 148} 149 150static void crash_protect_pages(int protect) 151{ 152 unsigned long size; 153 154 if (!crashk_res.end) 155 return; 156 size = resource_size(&crashk_res); 157 if (protect) 158 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 159 else 160 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 161} 162 163void arch_kexec_protect_crashkres(void) 164{ 165 crash_protect_pages(1); 166} 167 168void arch_kexec_unprotect_crashkres(void) 169{ 170 crash_protect_pages(0); 171} 172 173#endif 174 175/* 176 * Give back memory to hypervisor before new kdump is loaded 177 */ 178static int machine_kexec_prepare_kdump(void) 179{ 180#ifdef CONFIG_CRASH_DUMP 181 if (MACHINE_IS_VM) 182 diag10_range(PFN_DOWN(crashk_res.start), 183 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 184 return 0; 185#else 186 return -EINVAL; 187#endif 188} 189 190int machine_kexec_prepare(struct kimage *image) 191{ 192 void *reboot_code_buffer; 193 194 if (image->type == KEXEC_TYPE_CRASH) 195 return machine_kexec_prepare_kdump(); 196 197 /* We don't support anything but the default image type for now. */ 198 if (image->type != KEXEC_TYPE_DEFAULT) 199 return -EINVAL; 200 201 /* Get the destination where the assembler code should be copied to.*/ 202 reboot_code_buffer = page_to_virt(image->control_code_page); 203 204 /* Then copy it */ 205 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 206 return 0; 207} 208 209void machine_kexec_cleanup(struct kimage *image) 210{ 211} 212 213void machine_shutdown(void) 214{ 215} 216 217void machine_crash_shutdown(struct pt_regs *regs) 218{ 219 set_os_info_reipl_block(); 220} 221 222/* 223 * Do normal kexec 224 */ 225static void __do_machine_kexec(void *data) 226{ 227 unsigned long data_mover, entry, diag308_subcode; 228 struct kimage *image = data; 229 230 data_mover = page_to_phys(image->control_code_page); 231 entry = virt_to_phys(&image->head); 232 diag308_subcode = DIAG308_CLEAR_RESET; 233 if (sclp.has_iplcc) 234 diag308_subcode |= DIAG308_FLAG_EI; 235 s390_reset_system(); 236 237 call_nodat(3, void, (relocate_kernel_t)data_mover, 238 unsigned long, entry, 239 unsigned long, image->start, 240 unsigned long, diag308_subcode); 241 242 /* Die if kexec returns */ 243 disabled_wait(); 244} 245 246/* 247 * Reset system and call either kdump or normal kexec 248 */ 249static void __machine_kexec(void *data) 250{ 251 pfault_fini(); 252 tracing_off(); 253 debug_locks_off(); 254#ifdef CONFIG_CRASH_DUMP 255 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 256 __machine_kdump(data); 257#endif 258 __do_machine_kexec(data); 259} 260 261/* 262 * Do either kdump or normal kexec. In case of kdump we first ask 263 * purgatory, if kdump checksums are valid. 264 */ 265void machine_kexec(struct kimage *image) 266{ 267 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 268 return; 269 tracer_disable(); 270 smp_send_stop(); 271 smp_call_ipl_cpu(__machine_kexec, image); 272} 273