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 | |
34 | typedef void (*relocate_kernel_t)(unsigned long, unsigned long, unsigned long); |
35 | typedef int (*purgatory_t)(int); |
36 | |
37 | extern const unsigned char relocate_kernel[]; |
38 | extern 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 | */ |
46 | static 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 | */ |
78 | static 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 | */ |
122 | static 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 | |
137 | void 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 | |
150 | static void crash_protect_pages(int protect) |
151 | { |
152 | unsigned long size; |
153 | |
154 | if (!crashk_res.end) |
155 | return; |
156 | size = resource_size(res: &crashk_res); |
157 | if (protect) |
158 | set_memory_ro(addr: crashk_res.start, numpages: size >> PAGE_SHIFT); |
159 | else |
160 | set_memory_rw(addr: crashk_res.start, numpages: size >> PAGE_SHIFT); |
161 | } |
162 | |
163 | void arch_kexec_protect_crashkres(void) |
164 | { |
165 | crash_protect_pages(protect: 1); |
166 | } |
167 | |
168 | void arch_kexec_unprotect_crashkres(void) |
169 | { |
170 | crash_protect_pages(protect: 0); |
171 | } |
172 | |
173 | #endif |
174 | |
175 | /* |
176 | * Give back memory to hypervisor before new kdump is loaded |
177 | */ |
178 | static 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 | |
190 | int 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 | |
209 | void machine_kexec_cleanup(struct kimage *image) |
210 | { |
211 | } |
212 | |
213 | void machine_shutdown(void) |
214 | { |
215 | } |
216 | |
217 | void machine_crash_shutdown(struct pt_regs *regs) |
218 | { |
219 | set_os_info_reipl_block(); |
220 | } |
221 | |
222 | /* |
223 | * Do normal kexec |
224 | */ |
225 | static 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(address: &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 | */ |
249 | static 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(image: 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 | */ |
265 | void 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 | |