1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kexec for arm64
4 *
5 * Copyright (C) Linaro.
6 * Copyright (C) Huawei Futurewei Technologies.
7 */
8
9#include <linux/interrupt.h>
10#include <linux/irq.h>
11#include <linux/kernel.h>
12#include <linux/kexec.h>
13#include <linux/page-flags.h>
14#include <linux/reboot.h>
15#include <linux/set_memory.h>
16#include <linux/smp.h>
17
18#include <asm/cacheflush.h>
19#include <asm/cpu_ops.h>
20#include <asm/daifflags.h>
21#include <asm/memory.h>
22#include <asm/mmu.h>
23#include <asm/mmu_context.h>
24#include <asm/page.h>
25#include <asm/sections.h>
26#include <asm/trans_pgd.h>
27
28/**
29 * kexec_image_info - For debugging output.
30 */
31#define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
32static void _kexec_image_info(const char *func, int line,
33 const struct kimage *kimage)
34{
35 kexec_dprintk("%s:%d:\n", func, line);
36 kexec_dprintk(" kexec kimage info:\n");
37 kexec_dprintk(" type: %d\n", kimage->type);
38 kexec_dprintk(" head: %lx\n", kimage->head);
39 kexec_dprintk(" kern_reloc: %pa\n", &kimage->arch.kern_reloc);
40 kexec_dprintk(" el2_vectors: %pa\n", &kimage->arch.el2_vectors);
41}
42
43void machine_kexec_cleanup(struct kimage *kimage)
44{
45 /* Empty routine needed to avoid build errors. */
46}
47
48/**
49 * machine_kexec_prepare - Prepare for a kexec reboot.
50 *
51 * Called from the core kexec code when a kernel image is loaded.
52 * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus
53 * are stuck in the kernel. This avoids a panic once we hit machine_kexec().
54 */
55int machine_kexec_prepare(struct kimage *kimage)
56{
57 if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
58 pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
59 return -EBUSY;
60 }
61
62 return 0;
63}
64
65/**
66 * kexec_segment_flush - Helper to flush the kimage segments to PoC.
67 */
68static void kexec_segment_flush(const struct kimage *kimage)
69{
70 unsigned long i;
71
72 pr_debug("%s:\n", __func__);
73
74 for (i = 0; i < kimage->nr_segments; i++) {
75 pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
76 i,
77 kimage->segment[i].mem,
78 kimage->segment[i].mem + kimage->segment[i].memsz,
79 kimage->segment[i].memsz,
80 kimage->segment[i].memsz / PAGE_SIZE);
81
82 dcache_clean_inval_poc(
83 (unsigned long)phys_to_virt(address: kimage->segment[i].mem),
84 (unsigned long)phys_to_virt(address: kimage->segment[i].mem) +
85 kimage->segment[i].memsz);
86 }
87}
88
89/* Allocates pages for kexec page table */
90static void *kexec_page_alloc(void *arg)
91{
92 struct kimage *kimage = arg;
93 struct page *page = kimage_alloc_control_pages(image: kimage, order: 0);
94 void *vaddr = NULL;
95
96 if (!page)
97 return NULL;
98
99 vaddr = page_address(page);
100 memset(vaddr, 0, PAGE_SIZE);
101
102 return vaddr;
103}
104
105int machine_kexec_post_load(struct kimage *kimage)
106{
107 int rc;
108 pgd_t *trans_pgd;
109 void *reloc_code = page_to_virt(kimage->control_code_page);
110 long reloc_size;
111 struct trans_pgd_info info = {
112 .trans_alloc_page = kexec_page_alloc,
113 .trans_alloc_arg = kimage,
114 };
115
116 /* If in place, relocation is not used, only flush next kernel */
117 if (kimage->head & IND_DONE) {
118 kexec_segment_flush(kimage);
119 kexec_image_info(kimage);
120 return 0;
121 }
122
123 kimage->arch.el2_vectors = 0;
124 if (is_hyp_nvhe()) {
125 rc = trans_pgd_copy_el2_vectors(&info,
126 &kimage->arch.el2_vectors);
127 if (rc)
128 return rc;
129 }
130
131 /* Create a copy of the linear map */
132 trans_pgd = kexec_page_alloc(arg: kimage);
133 if (!trans_pgd)
134 return -ENOMEM;
135 rc = trans_pgd_create_copy(&info, &trans_pgd, PAGE_OFFSET, PAGE_END);
136 if (rc)
137 return rc;
138 kimage->arch.ttbr1 = __pa(trans_pgd);
139 kimage->arch.zero_page = __pa_symbol(empty_zero_page);
140
141 reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
142 memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
143 kimage->arch.kern_reloc = __pa(reloc_code);
144 rc = trans_pgd_idmap_page(&info, &kimage->arch.ttbr0,
145 &kimage->arch.t0sz, reloc_code);
146 if (rc)
147 return rc;
148 kimage->arch.phys_offset = virt_to_phys(address: kimage) - (long)kimage;
149
150 /* Flush the reloc_code in preparation for its execution. */
151 dcache_clean_inval_poc((unsigned long)reloc_code,
152 (unsigned long)reloc_code + reloc_size);
153 icache_inval_pou((uintptr_t)reloc_code,
154 (uintptr_t)reloc_code + reloc_size);
155 kexec_image_info(kimage);
156
157 return 0;
158}
159
160/**
161 * machine_kexec - Do the kexec reboot.
162 *
163 * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
164 */
165void machine_kexec(struct kimage *kimage)
166{
167 bool in_kexec_crash = (kimage == kexec_crash_image);
168 bool stuck_cpus = cpus_are_stuck_in_kernel();
169
170 /*
171 * New cpus may have become stuck_in_kernel after we loaded the image.
172 */
173 BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1)));
174 WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
175 "Some CPUs may be stale, kdump will be unreliable.\n");
176
177 pr_info("Bye!\n");
178
179 local_daif_mask();
180
181 /*
182 * Both restart and kernel_reloc will shutdown the MMU, disable data
183 * caches. However, restart will start new kernel or purgatory directly,
184 * kernel_reloc contains the body of arm64_relocate_new_kernel
185 * In kexec case, kimage->start points to purgatory assuming that
186 * kernel entry and dtb address are embedded in purgatory by
187 * userspace (kexec-tools).
188 * In kexec_file case, the kernel starts directly without purgatory.
189 */
190 if (kimage->head & IND_DONE) {
191 typeof(cpu_soft_restart) *restart;
192
193 cpu_install_idmap();
194 restart = (void *)__pa_symbol(cpu_soft_restart);
195 restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem,
196 0, 0);
197 } else {
198 void (*kernel_reloc)(struct kimage *kimage);
199
200 if (is_hyp_nvhe())
201 __hyp_set_vectors(kimage->arch.el2_vectors);
202 cpu_install_ttbr0(kimage->arch.ttbr0, kimage->arch.t0sz);
203 kernel_reloc = (void *)kimage->arch.kern_reloc;
204 kernel_reloc(kimage);
205 }
206
207 BUG(); /* Should never get here. */
208}
209
210static void machine_kexec_mask_interrupts(void)
211{
212 unsigned int i;
213 struct irq_desc *desc;
214
215 for_each_irq_desc(i, desc) {
216 struct irq_chip *chip;
217 int ret;
218
219 chip = irq_desc_get_chip(desc);
220 if (!chip)
221 continue;
222
223 /*
224 * First try to remove the active state. If this
225 * fails, try to EOI the interrupt.
226 */
227 ret = irq_set_irqchip_state(irq: i, which: IRQCHIP_STATE_ACTIVE, state: false);
228
229 if (ret && irqd_irq_inprogress(d: &desc->irq_data) &&
230 chip->irq_eoi)
231 chip->irq_eoi(&desc->irq_data);
232
233 if (chip->irq_mask)
234 chip->irq_mask(&desc->irq_data);
235
236 if (chip->irq_disable && !irqd_irq_disabled(d: &desc->irq_data))
237 chip->irq_disable(&desc->irq_data);
238 }
239}
240
241/**
242 * machine_crash_shutdown - shutdown non-crashing cpus and save registers
243 */
244void machine_crash_shutdown(struct pt_regs *regs)
245{
246 local_irq_disable();
247
248 /* shutdown non-crashing cpus */
249 crash_smp_send_stop();
250
251 /* for crashing cpu */
252 crash_save_cpu(regs, smp_processor_id());
253 machine_kexec_mask_interrupts();
254
255 pr_info("Starting crashdump kernel...\n");
256}
257
258#if defined(CONFIG_CRASH_DUMP) && defined(CONFIG_HIBERNATION)
259/*
260 * To preserve the crash dump kernel image, the relevant memory segments
261 * should be mapped again around the hibernation.
262 */
263void crash_prepare_suspend(void)
264{
265 if (kexec_crash_image)
266 arch_kexec_unprotect_crashkres();
267}
268
269void crash_post_resume(void)
270{
271 if (kexec_crash_image)
272 arch_kexec_protect_crashkres();
273}
274
275/*
276 * crash_is_nosave
277 *
278 * Return true only if a page is part of reserved memory for crash dump kernel,
279 * but does not hold any data of loaded kernel image.
280 *
281 * Note that all the pages in crash dump kernel memory have been initially
282 * marked as Reserved as memory was allocated via memblock_reserve().
283 *
284 * In hibernation, the pages which are Reserved and yet "nosave" are excluded
285 * from the hibernation iamge. crash_is_nosave() does thich check for crash
286 * dump kernel and will reduce the total size of hibernation image.
287 */
288
289bool crash_is_nosave(unsigned long pfn)
290{
291 int i;
292 phys_addr_t addr;
293
294 if (!crashk_res.end)
295 return false;
296
297 /* in reserved memory? */
298 addr = __pfn_to_phys(pfn);
299 if ((addr < crashk_res.start) || (crashk_res.end < addr)) {
300 if (!crashk_low_res.end)
301 return false;
302
303 if ((addr < crashk_low_res.start) || (crashk_low_res.end < addr))
304 return false;
305 }
306
307 if (!kexec_crash_image)
308 return true;
309
310 /* not part of loaded kernel image? */
311 for (i = 0; i < kexec_crash_image->nr_segments; i++)
312 if (addr >= kexec_crash_image->segment[i].mem &&
313 addr < (kexec_crash_image->segment[i].mem +
314 kexec_crash_image->segment[i].memsz))
315 return false;
316
317 return true;
318}
319
320void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
321{
322 unsigned long addr;
323 struct page *page;
324
325 for (addr = begin; addr < end; addr += PAGE_SIZE) {
326 page = phys_to_page(addr);
327 free_reserved_page(page);
328 }
329}
330#endif /* CONFIG_HIBERNATION */
331

source code of linux/arch/arm64/kernel/machine_kexec.c