summaryrefslogtreecommitdiffstats
path: root/arch/tile/kernel/machine_kexec.c
blob: e00d7179989e24946a20185709224d9afd97f1be (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 *
 * based on machine_kexec.c from other architectures in linux-2.6.18
 */

#include <linux/mm.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/cpumask.h>
#include <linux/kernel.h>
#include <linux/elf.h>
#include <linux/highmem.h>
#include <linux/mmu_context.h>
#include <linux/io.h>
#include <linux/timex.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/checksum.h>
#include <hv/hypervisor.h>


/*
 * This stuff is not in elf.h and is not in any other kernel include.
 * This stuff is needed below in the little boot notes parser to
 * extract the command line so we can pass it to the hypervisor.
 */
struct Elf32_Bhdr {
	Elf32_Word b_signature;
	Elf32_Word b_size;
	Elf32_Half b_checksum;
	Elf32_Half b_records;
};
#define ELF_BOOT_MAGIC		0x0E1FB007
#define EBN_COMMAND_LINE	0x00000004
#define roundupsz(X) (((X) + 3) & ~3)

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */


void machine_shutdown(void)
{
	/*
	 * Normally we would stop all the other processors here, but
	 * the check in machine_kexec_prepare below ensures we'll only
	 * get this far if we've been booted with "nosmp" on the
	 * command line or without CONFIG_SMP so there's nothing to do
	 * here (for now).
	 */
}

void machine_crash_shutdown(struct pt_regs *regs)
{
	/*
	 * Cannot happen.  This type of kexec is disabled on this
	 * architecture (and enforced in machine_kexec_prepare below).
	 */
}


int machine_kexec_prepare(struct kimage *image)
{
	if (num_online_cpus() > 1) {
		pr_warning("%s: detected attempt to kexec "
		       "with num_online_cpus() > 1\n",
		       __func__);
		return -ENOSYS;
	}
	if (image->type != KEXEC_TYPE_DEFAULT) {
		pr_warning("%s: detected attempt to kexec "
		       "with unsupported type: %d\n",
		       __func__,
		       image->type);
		return -ENOSYS;
	}
	return 0;
}

void machine_kexec_cleanup(struct kimage *image)
{
	/*
	 * We did nothing in machine_kexec_prepare,
	 * so we have nothing to do here.
	 */
}

/*
 * If we can find elf boot notes on this page, return the command
 * line.  Otherwise, silently return null.  Somewhat kludgy, but no
 * good way to do this without significantly rearchitecting the
 * architecture-independent kexec code.
 */

static unsigned char *kexec_bn2cl(void *pg)
{
	struct Elf32_Bhdr *bhdrp;
	Elf32_Nhdr *nhdrp;
	unsigned char *desc;
	unsigned char *command_line;
	__sum16 csum;

	bhdrp = (struct Elf32_Bhdr *) pg;

	/*
	 * This routine is invoked for every source page, so make
	 * sure to quietly ignore every impossible page.
	 */
	if (bhdrp->b_signature != ELF_BOOT_MAGIC ||
	    bhdrp->b_size > PAGE_SIZE)
		return 0;

	/*
	 * If we get a checksum mismatch, warn with the checksum
	 * so we can diagnose better.
	 */
	csum = ip_compute_csum(pg, bhdrp->b_size);
	if (csum != 0) {
		pr_warning("%s: bad checksum %#x (size %d)\n",
			   __func__, csum, bhdrp->b_size);
		return 0;
	}

	nhdrp = (Elf32_Nhdr *) (bhdrp + 1);

	while (nhdrp->n_type != EBN_COMMAND_LINE) {

		desc = (unsigned char *) (nhdrp + 1);
		desc += roundupsz(nhdrp->n_descsz);

		nhdrp = (Elf32_Nhdr *) desc;

		/* still in bounds? */
		if ((unsigned char *) (nhdrp + 1) >
		    ((unsigned char *) pg) + bhdrp->b_size) {

			pr_info("%s: out of bounds\n", __func__);
			return 0;
		}
	}

	command_line = (unsigned char *) (nhdrp + 1);
	desc = command_line;

	while (*desc != '\0') {
		desc++;
		if (((unsigned long)desc & PAGE_MASK) != (unsigned long)pg) {
			pr_info("%s: ran off end of page\n",
			       __func__);
			return 0;
		}
	}

	return command_line;
}

static void kexec_find_and_set_command_line(struct kimage *image)
{
	kimage_entry_t *ptr, entry;

	unsigned char *command_line = 0;
	unsigned char *r;
	HV_Errno hverr;

	for (ptr = &image->head;
	     (entry = *ptr) && !(entry & IND_DONE);
	     ptr = (entry & IND_INDIRECTION) ?
		     phys_to_virt((entry & PAGE_MASK)) : ptr + 1) {

		if ((entry & IND_SOURCE)) {
			void *va =
				kmap_atomic_pfn(entry >> PAGE_SHIFT);
			r = kexec_bn2cl(va);
			if (r) {
				command_line = r;
				break;
			}
			kunmap_atomic(va);
		}
	}

	if (command_line != 0) {
		pr_info("setting new command line to \"%s\"\n",
		       command_line);

		hverr = hv_set_command_line(
			(HV_VirtAddr) command_line, strlen(command_line));
		kunmap_atomic(command_line);
	} else {
		pr_info("%s: no command line found; making empty\n",
		       __func__);
		hverr = hv_set_command_line((HV_VirtAddr) command_line, 0);
	}
	if (hverr)
		pr_warning("%s: hv_set_command_line returned error: %d\n",
			   __func__, hverr);
}

/*
 * The kexec code range-checks all its PAs, so to avoid having it run
 * amok and allocate memory and then sequester it from every other
 * controller, we force it to come from controller zero.  We also
 * disable the oom-killer since if we do end up running out of memory,
 * that almost certainly won't help.
 */
struct page *kimage_alloc_pages_arch(gfp_t gfp_mask, unsigned int order)
{
	gfp_mask |= __GFP_THISNODE | __GFP_NORETRY;
	return alloc_pages_node(0, gfp_mask, order);
}

static void setup_quasi_va_is_pa(void)
{
	HV_PTE *pgtable;
	HV_PTE pte;
	int i;

	/*
	 * Flush our TLB to prevent conflicts between the previous contents
	 * and the new stuff we're about to add.
	 */
	local_flush_tlb_all();

	/* setup VA is PA, at least up to PAGE_OFFSET */

	pgtable = (HV_PTE *)current->mm->pgd;
	pte = hv_pte(_PAGE_KERNEL | _PAGE_HUGE_PAGE);
	pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3);

	for (i = 0; i < pgd_index(PAGE_OFFSET); i++) {
		unsigned long pfn = i << (HPAGE_SHIFT - PAGE_SHIFT);
		if (pfn_valid(pfn))
			__set_pte(&pgtable[i], pfn_pte(pfn, pte));
	}
}


NORET_TYPE void machine_kexec(struct kimage *image)
{
	void *reboot_code_buffer;
	NORET_TYPE void (*rnk)(unsigned long, void *, unsigned long)
		ATTRIB_NORET;

	/* Mask all interrupts before starting to reboot. */
	interrupt_mask_set_mask(~0ULL);

	kexec_find_and_set_command_line(image);

	/*
	 * Adjust the home caching of the control page to be cached on
	 * this cpu, and copy the assembly helper into the control
	 * code page, which we map in the vmalloc area.
	 */
	homecache_change_page_home(image->control_code_page, 0,
				   smp_processor_id());
	reboot_code_buffer = vmap(&image->control_code_page, 1, 0,
				  __pgprot(_PAGE_KERNEL | _PAGE_EXECUTABLE));
	memcpy(reboot_code_buffer, relocate_new_kernel,
	       relocate_new_kernel_size);
	__flush_icache_range(
		(unsigned long) reboot_code_buffer,
		(unsigned long) reboot_code_buffer + relocate_new_kernel_size);

	setup_quasi_va_is_pa();

	/* now call it */
	rnk = reboot_code_buffer;
	(*rnk)(image->head, reboot_code_buffer, image->start);
}