1 /*
2  * kexec for arm64
3  *
4  * Copyright (C) Linaro.
5  * Copyright (C) Huawei Futurewei Technologies.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/interrupt.h>
13 #include <linux/irq.h>
14 #include <linux/kernel.h>
15 #include <linux/kexec.h>
16 #include <linux/page-flags.h>
17 #include <linux/smp.h>
18 
19 #include <asm/cacheflush.h>
20 #include <asm/cpu_ops.h>
21 #include <asm/daifflags.h>
22 #include <asm/memory.h>
23 #include <asm/mmu.h>
24 #include <asm/mmu_context.h>
25 #include <asm/page.h>
26 
27 #include "cpu-reset.h"
28 
29 /* Global variables for the arm64_relocate_new_kernel routine. */
30 extern const unsigned char arm64_relocate_new_kernel[];
31 extern const unsigned long arm64_relocate_new_kernel_size;
32 
33 /**
34  * kexec_image_info - For debugging output.
35  */
36 #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
37 static void _kexec_image_info(const char *func, int line,
38 	const struct kimage *kimage)
39 {
40 	unsigned long i;
41 
42 	pr_debug("%s:%d:\n", func, line);
43 	pr_debug("  kexec kimage info:\n");
44 	pr_debug("    type:        %d\n", kimage->type);
45 	pr_debug("    start:       %lx\n", kimage->start);
46 	pr_debug("    head:        %lx\n", kimage->head);
47 	pr_debug("    nr_segments: %lu\n", kimage->nr_segments);
48 
49 	for (i = 0; i < kimage->nr_segments; i++) {
50 		pr_debug("      segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
51 			i,
52 			kimage->segment[i].mem,
53 			kimage->segment[i].mem + kimage->segment[i].memsz,
54 			kimage->segment[i].memsz,
55 			kimage->segment[i].memsz /  PAGE_SIZE);
56 	}
57 }
58 
59 void machine_kexec_cleanup(struct kimage *kimage)
60 {
61 	/* Empty routine needed to avoid build errors. */
62 }
63 
64 /**
65  * machine_kexec_prepare - Prepare for a kexec reboot.
66  *
67  * Called from the core kexec code when a kernel image is loaded.
68  * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus
69  * are stuck in the kernel. This avoids a panic once we hit machine_kexec().
70  */
71 int machine_kexec_prepare(struct kimage *kimage)
72 {
73 	kexec_image_info(kimage);
74 
75 	if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
76 		pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
77 		return -EBUSY;
78 	}
79 
80 	return 0;
81 }
82 
83 /**
84  * kexec_list_flush - Helper to flush the kimage list and source pages to PoC.
85  */
86 static void kexec_list_flush(struct kimage *kimage)
87 {
88 	kimage_entry_t *entry;
89 
90 	for (entry = &kimage->head; ; entry++) {
91 		unsigned int flag;
92 		void *addr;
93 
94 		/* flush the list entries. */
95 		__flush_dcache_area(entry, sizeof(kimage_entry_t));
96 
97 		flag = *entry & IND_FLAGS;
98 		if (flag == IND_DONE)
99 			break;
100 
101 		addr = phys_to_virt(*entry & PAGE_MASK);
102 
103 		switch (flag) {
104 		case IND_INDIRECTION:
105 			/* Set entry point just before the new list page. */
106 			entry = (kimage_entry_t *)addr - 1;
107 			break;
108 		case IND_SOURCE:
109 			/* flush the source pages. */
110 			__flush_dcache_area(addr, PAGE_SIZE);
111 			break;
112 		case IND_DESTINATION:
113 			break;
114 		default:
115 			BUG();
116 		}
117 	}
118 }
119 
120 /**
121  * kexec_segment_flush - Helper to flush the kimage segments to PoC.
122  */
123 static void kexec_segment_flush(const struct kimage *kimage)
124 {
125 	unsigned long i;
126 
127 	pr_debug("%s:\n", __func__);
128 
129 	for (i = 0; i < kimage->nr_segments; i++) {
130 		pr_debug("  segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
131 			i,
132 			kimage->segment[i].mem,
133 			kimage->segment[i].mem + kimage->segment[i].memsz,
134 			kimage->segment[i].memsz,
135 			kimage->segment[i].memsz /  PAGE_SIZE);
136 
137 		__flush_dcache_area(phys_to_virt(kimage->segment[i].mem),
138 			kimage->segment[i].memsz);
139 	}
140 }
141 
142 /**
143  * machine_kexec - Do the kexec reboot.
144  *
145  * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
146  */
147 void machine_kexec(struct kimage *kimage)
148 {
149 	phys_addr_t reboot_code_buffer_phys;
150 	void *reboot_code_buffer;
151 	bool in_kexec_crash = (kimage == kexec_crash_image);
152 	bool stuck_cpus = cpus_are_stuck_in_kernel();
153 
154 	/*
155 	 * New cpus may have become stuck_in_kernel after we loaded the image.
156 	 */
157 	BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1)));
158 	WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
159 		"Some CPUs may be stale, kdump will be unreliable.\n");
160 
161 	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
162 	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
163 
164 	kexec_image_info(kimage);
165 
166 	pr_debug("%s:%d: control_code_page:        %p\n", __func__, __LINE__,
167 		kimage->control_code_page);
168 	pr_debug("%s:%d: reboot_code_buffer_phys:  %pa\n", __func__, __LINE__,
169 		&reboot_code_buffer_phys);
170 	pr_debug("%s:%d: reboot_code_buffer:       %p\n", __func__, __LINE__,
171 		reboot_code_buffer);
172 	pr_debug("%s:%d: relocate_new_kernel:      %p\n", __func__, __LINE__,
173 		arm64_relocate_new_kernel);
174 	pr_debug("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
175 		__func__, __LINE__, arm64_relocate_new_kernel_size,
176 		arm64_relocate_new_kernel_size);
177 
178 	/*
179 	 * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
180 	 * after the kernel is shut down.
181 	 */
182 	memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
183 		arm64_relocate_new_kernel_size);
184 
185 	/* Flush the reboot_code_buffer in preparation for its execution. */
186 	__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
187 
188 	/*
189 	 * Although we've killed off the secondary CPUs, we don't update
190 	 * the online mask if we're handling a crash kernel and consequently
191 	 * need to avoid flush_icache_range(), which will attempt to IPI
192 	 * the offline CPUs. Therefore, we must use the __* variant here.
193 	 */
194 	__flush_icache_range((uintptr_t)reboot_code_buffer,
195 			     arm64_relocate_new_kernel_size);
196 
197 	/* Flush the kimage list and its buffers. */
198 	kexec_list_flush(kimage);
199 
200 	/* Flush the new image if already in place. */
201 	if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE))
202 		kexec_segment_flush(kimage);
203 
204 	pr_info("Bye!\n");
205 
206 	local_daif_mask();
207 
208 	/*
209 	 * cpu_soft_restart will shutdown the MMU, disable data caches, then
210 	 * transfer control to the reboot_code_buffer which contains a copy of
211 	 * the arm64_relocate_new_kernel routine.  arm64_relocate_new_kernel
212 	 * uses physical addressing to relocate the new image to its final
213 	 * position and transfers control to the image entry point when the
214 	 * relocation is complete.
215 	 */
216 
217 	cpu_soft_restart(reboot_code_buffer_phys, kimage->head, kimage->start, 0);
218 
219 	BUG(); /* Should never get here. */
220 }
221 
222 static void machine_kexec_mask_interrupts(void)
223 {
224 	unsigned int i;
225 	struct irq_desc *desc;
226 
227 	for_each_irq_desc(i, desc) {
228 		struct irq_chip *chip;
229 		int ret;
230 
231 		chip = irq_desc_get_chip(desc);
232 		if (!chip)
233 			continue;
234 
235 		/*
236 		 * First try to remove the active state. If this
237 		 * fails, try to EOI the interrupt.
238 		 */
239 		ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
240 
241 		if (ret && irqd_irq_inprogress(&desc->irq_data) &&
242 		    chip->irq_eoi)
243 			chip->irq_eoi(&desc->irq_data);
244 
245 		if (chip->irq_mask)
246 			chip->irq_mask(&desc->irq_data);
247 
248 		if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
249 			chip->irq_disable(&desc->irq_data);
250 	}
251 }
252 
253 /**
254  * machine_crash_shutdown - shutdown non-crashing cpus and save registers
255  */
256 void machine_crash_shutdown(struct pt_regs *regs)
257 {
258 	local_irq_disable();
259 
260 	/* shutdown non-crashing cpus */
261 	crash_smp_send_stop();
262 
263 	/* for crashing cpu */
264 	crash_save_cpu(regs, smp_processor_id());
265 	machine_kexec_mask_interrupts();
266 
267 	pr_info("Starting crashdump kernel...\n");
268 }
269 
270 void arch_kexec_protect_crashkres(void)
271 {
272 	int i;
273 
274 	kexec_segment_flush(kexec_crash_image);
275 
276 	for (i = 0; i < kexec_crash_image->nr_segments; i++)
277 		set_memory_valid(
278 			__phys_to_virt(kexec_crash_image->segment[i].mem),
279 			kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0);
280 }
281 
282 void arch_kexec_unprotect_crashkres(void)
283 {
284 	int i;
285 
286 	for (i = 0; i < kexec_crash_image->nr_segments; i++)
287 		set_memory_valid(
288 			__phys_to_virt(kexec_crash_image->segment[i].mem),
289 			kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1);
290 }
291 
292 #ifdef CONFIG_HIBERNATION
293 /*
294  * To preserve the crash dump kernel image, the relevant memory segments
295  * should be mapped again around the hibernation.
296  */
297 void crash_prepare_suspend(void)
298 {
299 	if (kexec_crash_image)
300 		arch_kexec_unprotect_crashkres();
301 }
302 
303 void crash_post_resume(void)
304 {
305 	if (kexec_crash_image)
306 		arch_kexec_protect_crashkres();
307 }
308 
309 /*
310  * crash_is_nosave
311  *
312  * Return true only if a page is part of reserved memory for crash dump kernel,
313  * but does not hold any data of loaded kernel image.
314  *
315  * Note that all the pages in crash dump kernel memory have been initially
316  * marked as Reserved in kexec_reserve_crashkres_pages().
317  *
318  * In hibernation, the pages which are Reserved and yet "nosave" are excluded
319  * from the hibernation iamge. crash_is_nosave() does thich check for crash
320  * dump kernel and will reduce the total size of hibernation image.
321  */
322 
323 bool crash_is_nosave(unsigned long pfn)
324 {
325 	int i;
326 	phys_addr_t addr;
327 
328 	if (!crashk_res.end)
329 		return false;
330 
331 	/* in reserved memory? */
332 	addr = __pfn_to_phys(pfn);
333 	if ((addr < crashk_res.start) || (crashk_res.end < addr))
334 		return false;
335 
336 	if (!kexec_crash_image)
337 		return true;
338 
339 	/* not part of loaded kernel image? */
340 	for (i = 0; i < kexec_crash_image->nr_segments; i++)
341 		if (addr >= kexec_crash_image->segment[i].mem &&
342 				addr < (kexec_crash_image->segment[i].mem +
343 					kexec_crash_image->segment[i].memsz))
344 			return false;
345 
346 	return true;
347 }
348 
349 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
350 {
351 	unsigned long addr;
352 	struct page *page;
353 
354 	for (addr = begin; addr < end; addr += PAGE_SIZE) {
355 		page = phys_to_page(addr);
356 		ClearPageReserved(page);
357 		free_reserved_page(page);
358 	}
359 }
360 #endif /* CONFIG_HIBERNATION */
361 
362 void arch_crash_save_vmcoreinfo(void)
363 {
364 	VMCOREINFO_NUMBER(VA_BITS);
365 	/* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */
366 	vmcoreinfo_append_str("NUMBER(kimage_voffset)=0x%llx\n",
367 						kimage_voffset);
368 	vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%llx\n",
369 						PHYS_OFFSET);
370 	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
371 }
372