1/*
2 * machine_kexec.c - handle transition of Linux booting another kernel
3 */
4
5#include <linux/mm.h>
6#include <linux/kexec.h>
7#include <linux/delay.h>
8#include <linux/reboot.h>
9#include <linux/io.h>
10#include <linux/irq.h>
11#include <linux/memblock.h>
12#include <asm/pgtable.h>
13#include <linux/of_fdt.h>
14#include <asm/pgalloc.h>
15#include <asm/mmu_context.h>
16#include <asm/cacheflush.h>
17#include <asm/fncpy.h>
18#include <asm/mach-types.h>
19#include <asm/smp_plat.h>
20#include <asm/system_misc.h>
21
22extern void relocate_new_kernel(void);
23extern const unsigned int relocate_new_kernel_size;
24
25extern unsigned long kexec_start_address;
26extern unsigned long kexec_indirection_page;
27extern unsigned long kexec_mach_type;
28extern unsigned long kexec_boot_atags;
29
30static atomic_t waiting_for_crash_ipi;
31
32static unsigned long dt_mem;
33/*
34 * Provide a dummy crash_notes definition while crash dump arrives to arm.
35 * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
36 */
37
38int machine_kexec_prepare(struct kimage *image)
39{
40	struct kexec_segment *current_segment;
41	__be32 header;
42	int i, err;
43
44	/*
45	 * Validate that if the current HW supports SMP, then the SW supports
46	 * and implements CPU hotplug for the current HW. If not, we won't be
47	 * able to kexec reliably, so fail the prepare operation.
48	 */
49	if (num_possible_cpus() > 1 && platform_can_secondary_boot() &&
50	    !platform_can_cpu_hotplug())
51		return -EINVAL;
52
53	/*
54	 * No segment at default ATAGs address. try to locate
55	 * a dtb using magic.
56	 */
57	for (i = 0; i < image->nr_segments; i++) {
58		current_segment = &image->segment[i];
59
60		if (!memblock_is_region_memory(current_segment->mem,
61					       current_segment->memsz))
62			return -EINVAL;
63
64		err = get_user(header, (__be32*)current_segment->buf);
65		if (err)
66			return err;
67
68		if (be32_to_cpu(header) == OF_DT_HEADER)
69			dt_mem = current_segment->mem;
70	}
71	return 0;
72}
73
74void machine_kexec_cleanup(struct kimage *image)
75{
76}
77
78void machine_crash_nonpanic_core(void *unused)
79{
80	struct pt_regs regs;
81
82	crash_setup_regs(&regs, NULL);
83	printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
84	       smp_processor_id());
85	crash_save_cpu(&regs, smp_processor_id());
86	flush_cache_all();
87
88	set_cpu_online(smp_processor_id(), false);
89	atomic_dec(&waiting_for_crash_ipi);
90	while (1)
91		cpu_relax();
92}
93
94static void machine_kexec_mask_interrupts(void)
95{
96	unsigned int i;
97	struct irq_desc *desc;
98
99	for_each_irq_desc(i, desc) {
100		struct irq_chip *chip;
101
102		chip = irq_desc_get_chip(desc);
103		if (!chip)
104			continue;
105
106		if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
107			chip->irq_eoi(&desc->irq_data);
108
109		if (chip->irq_mask)
110			chip->irq_mask(&desc->irq_data);
111
112		if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
113			chip->irq_disable(&desc->irq_data);
114	}
115}
116
117void machine_crash_shutdown(struct pt_regs *regs)
118{
119	unsigned long msecs;
120
121	local_irq_disable();
122
123	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
124	smp_call_function(machine_crash_nonpanic_core, NULL, false);
125	msecs = 1000; /* Wait at most a second for the other cpus to stop */
126	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
127		mdelay(1);
128		msecs--;
129	}
130	if (atomic_read(&waiting_for_crash_ipi) > 0)
131		pr_warn("Non-crashing CPUs did not react to IPI\n");
132
133	crash_save_cpu(regs, smp_processor_id());
134	machine_kexec_mask_interrupts();
135
136	pr_info("Loading crashdump kernel...\n");
137}
138
139/*
140 * Function pointer to optional machine-specific reinitialization
141 */
142void (*kexec_reinit)(void);
143
144void machine_kexec(struct kimage *image)
145{
146	unsigned long page_list;
147	unsigned long reboot_code_buffer_phys;
148	unsigned long reboot_entry = (unsigned long)relocate_new_kernel;
149	unsigned long reboot_entry_phys;
150	void *reboot_code_buffer;
151
152	/*
153	 * This can only happen if machine_shutdown() failed to disable some
154	 * CPU, and that can only happen if the checks in
155	 * machine_kexec_prepare() were not correct. If this fails, we can't
156	 * reliably kexec anyway, so BUG_ON is appropriate.
157	 */
158	BUG_ON(num_online_cpus() > 1);
159
160	page_list = image->head & PAGE_MASK;
161
162	/* we need both effective and real address here */
163	reboot_code_buffer_phys =
164	    page_to_pfn(image->control_code_page) << PAGE_SHIFT;
165	reboot_code_buffer = page_address(image->control_code_page);
166
167	/* Prepare parameters for reboot_code_buffer*/
168	set_kernel_text_rw();
169	kexec_start_address = image->start;
170	kexec_indirection_page = page_list;
171	kexec_mach_type = machine_arch_type;
172	kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET
173				     + KEXEC_ARM_ATAGS_OFFSET;
174
175	/* copy our kernel relocation code to the control code page */
176	reboot_entry = fncpy(reboot_code_buffer,
177			     reboot_entry,
178			     relocate_new_kernel_size);
179	reboot_entry_phys = (unsigned long)reboot_entry +
180		(reboot_code_buffer_phys - (unsigned long)reboot_code_buffer);
181
182	pr_info("Bye!\n");
183
184	if (kexec_reinit)
185		kexec_reinit();
186
187	soft_restart(reboot_entry_phys);
188}
189
190void arch_crash_save_vmcoreinfo(void)
191{
192#ifdef CONFIG_ARM_LPAE
193	VMCOREINFO_CONFIG(ARM_LPAE);
194#endif
195}
196