1 /*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 *
14 * based on machine_kexec.c from other architectures in linux-2.6.18
15 */
16
17 #include <linux/mm.h>
18 #include <linux/kexec.h>
19 #include <linux/delay.h>
20 #include <linux/reboot.h>
21 #include <linux/errno.h>
22 #include <linux/vmalloc.h>
23 #include <linux/cpumask.h>
24 #include <linux/kernel.h>
25 #include <linux/elf.h>
26 #include <linux/highmem.h>
27 #include <linux/mmu_context.h>
28 #include <linux/io.h>
29 #include <linux/timex.h>
30 #include <asm/pgtable.h>
31 #include <asm/pgalloc.h>
32 #include <asm/cacheflush.h>
33 #include <asm/checksum.h>
34 #include <hv/hypervisor.h>
35
36
37 /*
38 * This stuff is not in elf.h and is not in any other kernel include.
39 * This stuff is needed below in the little boot notes parser to
40 * extract the command line so we can pass it to the hypervisor.
41 */
42 struct Elf32_Bhdr {
43 Elf32_Word b_signature;
44 Elf32_Word b_size;
45 Elf32_Half b_checksum;
46 Elf32_Half b_records;
47 };
48 #define ELF_BOOT_MAGIC 0x0E1FB007
49 #define EBN_COMMAND_LINE 0x00000004
50 #define roundupsz(X) (((X) + 3) & ~3)
51
52 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
53
54
machine_shutdown(void)55 void machine_shutdown(void)
56 {
57 /*
58 * Normally we would stop all the other processors here, but
59 * the check in machine_kexec_prepare below ensures we'll only
60 * get this far if we've been booted with "nosmp" on the
61 * command line or without CONFIG_SMP so there's nothing to do
62 * here (for now).
63 */
64 }
65
machine_crash_shutdown(struct pt_regs * regs)66 void machine_crash_shutdown(struct pt_regs *regs)
67 {
68 /*
69 * Cannot happen. This type of kexec is disabled on this
70 * architecture (and enforced in machine_kexec_prepare below).
71 */
72 }
73
74
machine_kexec_prepare(struct kimage * image)75 int machine_kexec_prepare(struct kimage *image)
76 {
77 if (num_online_cpus() > 1) {
78 pr_warning("%s: detected attempt to kexec "
79 "with num_online_cpus() > 1\n",
80 __func__);
81 return -ENOSYS;
82 }
83 if (image->type != KEXEC_TYPE_DEFAULT) {
84 pr_warning("%s: detected attempt to kexec "
85 "with unsupported type: %d\n",
86 __func__,
87 image->type);
88 return -ENOSYS;
89 }
90 return 0;
91 }
92
machine_kexec_cleanup(struct kimage * image)93 void machine_kexec_cleanup(struct kimage *image)
94 {
95 /*
96 * We did nothing in machine_kexec_prepare,
97 * so we have nothing to do here.
98 */
99 }
100
101 /*
102 * If we can find elf boot notes on this page, return the command
103 * line. Otherwise, silently return null. Somewhat kludgy, but no
104 * good way to do this without significantly rearchitecting the
105 * architecture-independent kexec code.
106 */
107
kexec_bn2cl(void * pg)108 static unsigned char *kexec_bn2cl(void *pg)
109 {
110 struct Elf32_Bhdr *bhdrp;
111 Elf32_Nhdr *nhdrp;
112 unsigned char *desc;
113 unsigned char *command_line;
114 __sum16 csum;
115
116 bhdrp = (struct Elf32_Bhdr *) pg;
117
118 /*
119 * This routine is invoked for every source page, so make
120 * sure to quietly ignore every impossible page.
121 */
122 if (bhdrp->b_signature != ELF_BOOT_MAGIC ||
123 bhdrp->b_size > PAGE_SIZE)
124 return 0;
125
126 /*
127 * If we get a checksum mismatch, warn with the checksum
128 * so we can diagnose better.
129 */
130 csum = ip_compute_csum(pg, bhdrp->b_size);
131 if (csum != 0) {
132 pr_warning("%s: bad checksum %#x (size %d)\n",
133 __func__, csum, bhdrp->b_size);
134 return 0;
135 }
136
137 nhdrp = (Elf32_Nhdr *) (bhdrp + 1);
138
139 while (nhdrp->n_type != EBN_COMMAND_LINE) {
140
141 desc = (unsigned char *) (nhdrp + 1);
142 desc += roundupsz(nhdrp->n_descsz);
143
144 nhdrp = (Elf32_Nhdr *) desc;
145
146 /* still in bounds? */
147 if ((unsigned char *) (nhdrp + 1) >
148 ((unsigned char *) pg) + bhdrp->b_size) {
149
150 pr_info("%s: out of bounds\n", __func__);
151 return 0;
152 }
153 }
154
155 command_line = (unsigned char *) (nhdrp + 1);
156 desc = command_line;
157
158 while (*desc != '\0') {
159 desc++;
160 if (((unsigned long)desc & PAGE_MASK) != (unsigned long)pg) {
161 pr_info("%s: ran off end of page\n",
162 __func__);
163 return 0;
164 }
165 }
166
167 return command_line;
168 }
169
kexec_find_and_set_command_line(struct kimage * image)170 static void kexec_find_and_set_command_line(struct kimage *image)
171 {
172 kimage_entry_t *ptr, entry;
173
174 unsigned char *command_line = 0;
175 unsigned char *r;
176 HV_Errno hverr;
177
178 for (ptr = &image->head;
179 (entry = *ptr) && !(entry & IND_DONE);
180 ptr = (entry & IND_INDIRECTION) ?
181 phys_to_virt((entry & PAGE_MASK)) : ptr + 1) {
182
183 if ((entry & IND_SOURCE)) {
184 void *va =
185 kmap_atomic_pfn(entry >> PAGE_SHIFT);
186 r = kexec_bn2cl(va);
187 if (r) {
188 command_line = r;
189 break;
190 }
191 kunmap_atomic(va);
192 }
193 }
194
195 if (command_line != 0) {
196 pr_info("setting new command line to \"%s\"\n",
197 command_line);
198
199 hverr = hv_set_command_line(
200 (HV_VirtAddr) command_line, strlen(command_line));
201 kunmap_atomic(command_line);
202 } else {
203 pr_info("%s: no command line found; making empty\n",
204 __func__);
205 hverr = hv_set_command_line((HV_VirtAddr) command_line, 0);
206 }
207 if (hverr)
208 pr_warning("%s: hv_set_command_line returned error: %d\n",
209 __func__, hverr);
210 }
211
212 /*
213 * The kexec code range-checks all its PAs, so to avoid having it run
214 * amok and allocate memory and then sequester it from every other
215 * controller, we force it to come from controller zero. We also
216 * disable the oom-killer since if we do end up running out of memory,
217 * that almost certainly won't help.
218 */
kimage_alloc_pages_arch(gfp_t gfp_mask,unsigned int order)219 struct page *kimage_alloc_pages_arch(gfp_t gfp_mask, unsigned int order)
220 {
221 gfp_mask |= __GFP_THISNODE | __GFP_NORETRY;
222 return alloc_pages_node(0, gfp_mask, order);
223 }
224
setup_quasi_va_is_pa(void)225 static void setup_quasi_va_is_pa(void)
226 {
227 HV_PTE *pgtable;
228 HV_PTE pte;
229 int i;
230
231 /*
232 * Flush our TLB to prevent conflicts between the previous contents
233 * and the new stuff we're about to add.
234 */
235 local_flush_tlb_all();
236
237 /* setup VA is PA, at least up to PAGE_OFFSET */
238
239 pgtable = (HV_PTE *)current->mm->pgd;
240 pte = hv_pte(_PAGE_KERNEL | _PAGE_HUGE_PAGE);
241 pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3);
242
243 for (i = 0; i < pgd_index(PAGE_OFFSET); i++) {
244 unsigned long pfn = i << (HPAGE_SHIFT - PAGE_SHIFT);
245 if (pfn_valid(pfn))
246 __set_pte(&pgtable[i], pfn_pte(pfn, pte));
247 }
248 }
249
250
machine_kexec(struct kimage * image)251 void machine_kexec(struct kimage *image)
252 {
253 void *reboot_code_buffer;
254 void (*rnk)(unsigned long, void *, unsigned long)
255 __noreturn;
256
257 /* Mask all interrupts before starting to reboot. */
258 interrupt_mask_set_mask(~0ULL);
259
260 kexec_find_and_set_command_line(image);
261
262 /*
263 * Adjust the home caching of the control page to be cached on
264 * this cpu, and copy the assembly helper into the control
265 * code page, which we map in the vmalloc area.
266 */
267 homecache_change_page_home(image->control_code_page, 0,
268 smp_processor_id());
269 reboot_code_buffer = vmap(&image->control_code_page, 1, 0,
270 __pgprot(_PAGE_KERNEL | _PAGE_EXECUTABLE));
271 memcpy(reboot_code_buffer, relocate_new_kernel,
272 relocate_new_kernel_size);
273 __flush_icache_range(
274 (unsigned long) reboot_code_buffer,
275 (unsigned long) reboot_code_buffer + relocate_new_kernel_size);
276
277 setup_quasi_va_is_pa();
278
279 /* now call it */
280 rnk = reboot_code_buffer;
281 (*rnk)(image->head, reboot_code_buffer, image->start);
282 }
283