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 <asm/tlbflush.h>
35 #include <asm/homecache.h>
36 #include <hv/hypervisor.h>
37
38
39 /*
40 * This stuff is not in elf.h and is not in any other kernel include.
41 * This stuff is needed below in the little boot notes parser to
42 * extract the command line so we can pass it to the hypervisor.
43 */
44 struct Elf32_Bhdr {
45 Elf32_Word b_signature;
46 Elf32_Word b_size;
47 Elf32_Half b_checksum;
48 Elf32_Half b_records;
49 };
50 #define ELF_BOOT_MAGIC 0x0E1FB007
51 #define EBN_COMMAND_LINE 0x00000004
52 #define roundupsz(X) (((X) + 3) & ~3)
53
54 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
55
56
machine_shutdown(void)57 void machine_shutdown(void)
58 {
59 /*
60 * Normally we would stop all the other processors here, but
61 * the check in machine_kexec_prepare below ensures we'll only
62 * get this far if we've been booted with "nosmp" on the
63 * command line or without CONFIG_SMP so there's nothing to do
64 * here (for now).
65 */
66 }
67
machine_crash_shutdown(struct pt_regs * regs)68 void machine_crash_shutdown(struct pt_regs *regs)
69 {
70 /*
71 * Cannot happen. This type of kexec is disabled on this
72 * architecture (and enforced in machine_kexec_prepare below).
73 */
74 }
75
76
machine_kexec_prepare(struct kimage * image)77 int machine_kexec_prepare(struct kimage *image)
78 {
79 if (num_online_cpus() > 1) {
80 pr_warning("%s: detected attempt to kexec "
81 "with num_online_cpus() > 1\n",
82 __func__);
83 return -ENOSYS;
84 }
85 if (image->type != KEXEC_TYPE_DEFAULT) {
86 pr_warning("%s: detected attempt to kexec "
87 "with unsupported type: %d\n",
88 __func__,
89 image->type);
90 return -ENOSYS;
91 }
92 return 0;
93 }
94
machine_kexec_cleanup(struct kimage * image)95 void machine_kexec_cleanup(struct kimage *image)
96 {
97 /*
98 * We did nothing in machine_kexec_prepare,
99 * so we have nothing to do here.
100 */
101 }
102
103 /*
104 * If we can find elf boot notes on this page, return the command
105 * line. Otherwise, silently return null. Somewhat kludgy, but no
106 * good way to do this without significantly rearchitecting the
107 * architecture-independent kexec code.
108 */
109
kexec_bn2cl(void * pg)110 static unsigned char *kexec_bn2cl(void *pg)
111 {
112 struct Elf32_Bhdr *bhdrp;
113 Elf32_Nhdr *nhdrp;
114 unsigned char *desc;
115 unsigned char *command_line;
116 __sum16 csum;
117
118 bhdrp = (struct Elf32_Bhdr *) pg;
119
120 /*
121 * This routine is invoked for every source page, so make
122 * sure to quietly ignore every impossible page.
123 */
124 if (bhdrp->b_signature != ELF_BOOT_MAGIC ||
125 bhdrp->b_size > PAGE_SIZE)
126 return 0;
127
128 /*
129 * If we get a checksum mismatch, warn with the checksum
130 * so we can diagnose better.
131 */
132 csum = ip_compute_csum(pg, bhdrp->b_size);
133 if (csum != 0) {
134 pr_warning("%s: bad checksum %#x (size %d)\n",
135 __func__, csum, bhdrp->b_size);
136 return 0;
137 }
138
139 nhdrp = (Elf32_Nhdr *) (bhdrp + 1);
140
141 while (nhdrp->n_type != EBN_COMMAND_LINE) {
142
143 desc = (unsigned char *) (nhdrp + 1);
144 desc += roundupsz(nhdrp->n_descsz);
145
146 nhdrp = (Elf32_Nhdr *) desc;
147
148 /* still in bounds? */
149 if ((unsigned char *) (nhdrp + 1) >
150 ((unsigned char *) pg) + bhdrp->b_size) {
151
152 pr_info("%s: out of bounds\n", __func__);
153 return 0;
154 }
155 }
156
157 command_line = (unsigned char *) (nhdrp + 1);
158 desc = command_line;
159
160 while (*desc != '\0') {
161 desc++;
162 if (((unsigned long)desc & PAGE_MASK) != (unsigned long)pg) {
163 pr_info("%s: ran off end of page\n",
164 __func__);
165 return 0;
166 }
167 }
168
169 return command_line;
170 }
171
kexec_find_and_set_command_line(struct kimage * image)172 static void kexec_find_and_set_command_line(struct kimage *image)
173 {
174 kimage_entry_t *ptr, entry;
175
176 unsigned char *command_line = 0;
177 unsigned char *r;
178 HV_Errno hverr;
179
180 for (ptr = &image->head;
181 (entry = *ptr) && !(entry & IND_DONE);
182 ptr = (entry & IND_INDIRECTION) ?
183 phys_to_virt((entry & PAGE_MASK)) : ptr + 1) {
184
185 if ((entry & IND_SOURCE)) {
186 void *va =
187 kmap_atomic_pfn(entry >> PAGE_SHIFT);
188 r = kexec_bn2cl(va);
189 if (r) {
190 command_line = r;
191 break;
192 }
193 kunmap_atomic(va);
194 }
195 }
196
197 if (command_line != 0) {
198 pr_info("setting new command line to \"%s\"\n",
199 command_line);
200
201 hverr = hv_set_command_line(
202 (HV_VirtAddr) command_line, strlen(command_line));
203 kunmap_atomic(command_line);
204 } else {
205 pr_info("%s: no command line found; making empty\n",
206 __func__);
207 hverr = hv_set_command_line((HV_VirtAddr) command_line, 0);
208 }
209 if (hverr)
210 pr_warning("%s: hv_set_command_line returned error: %d\n",
211 __func__, hverr);
212 }
213
214 /*
215 * The kexec code range-checks all its PAs, so to avoid having it run
216 * amok and allocate memory and then sequester it from every other
217 * controller, we force it to come from controller zero. We also
218 * disable the oom-killer since if we do end up running out of memory,
219 * that almost certainly won't help.
220 */
kimage_alloc_pages_arch(gfp_t gfp_mask,unsigned int order)221 struct page *kimage_alloc_pages_arch(gfp_t gfp_mask, unsigned int order)
222 {
223 gfp_mask |= __GFP_THISNODE | __GFP_NORETRY;
224 return alloc_pages_node(0, gfp_mask, order);
225 }
226
227 /*
228 * Address range in which pa=va mapping is set in setup_quasi_va_is_pa().
229 * For tilepro, PAGE_OFFSET is used since this is the largest possbile value
230 * for tilepro, while for tilegx, we limit it to entire middle level page
231 * table which we assume has been allocated and is undoubtedly large enough.
232 */
233 #ifndef __tilegx__
234 #define QUASI_VA_IS_PA_ADDR_RANGE PAGE_OFFSET
235 #else
236 #define QUASI_VA_IS_PA_ADDR_RANGE PGDIR_SIZE
237 #endif
238
setup_quasi_va_is_pa(void)239 static void setup_quasi_va_is_pa(void)
240 {
241 HV_PTE pte;
242 unsigned long i;
243
244 /*
245 * Flush our TLB to prevent conflicts between the previous contents
246 * and the new stuff we're about to add.
247 */
248 local_flush_tlb_all();
249
250 /*
251 * setup VA is PA, at least up to QUASI_VA_IS_PA_ADDR_RANGE.
252 * Note here we assume that level-1 page table is defined by
253 * HPAGE_SIZE.
254 */
255 pte = hv_pte(_PAGE_KERNEL | _PAGE_HUGE_PAGE);
256 pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3);
257 for (i = 0; i < (QUASI_VA_IS_PA_ADDR_RANGE >> HPAGE_SHIFT); i++) {
258 unsigned long vaddr = i << HPAGE_SHIFT;
259 pgd_t *pgd = pgd_offset(current->mm, vaddr);
260 pud_t *pud = pud_offset(pgd, vaddr);
261 pte_t *ptep = (pte_t *) pmd_offset(pud, vaddr);
262 unsigned long pfn = i << (HPAGE_SHIFT - PAGE_SHIFT);
263
264 if (pfn_valid(pfn))
265 __set_pte(ptep, pfn_pte(pfn, pte));
266 }
267 }
268
269
machine_kexec(struct kimage * image)270 void machine_kexec(struct kimage *image)
271 {
272 void *reboot_code_buffer;
273 pte_t *ptep;
274 void (*rnk)(unsigned long, void *, unsigned long)
275 __noreturn;
276
277 /* Mask all interrupts before starting to reboot. */
278 interrupt_mask_set_mask(~0ULL);
279
280 kexec_find_and_set_command_line(image);
281
282 /*
283 * Adjust the home caching of the control page to be cached on
284 * this cpu, and copy the assembly helper into the control
285 * code page, which we map in the vmalloc area.
286 */
287 homecache_change_page_home(image->control_code_page, 0,
288 smp_processor_id());
289 reboot_code_buffer = page_address(image->control_code_page);
290 BUG_ON(reboot_code_buffer == NULL);
291 ptep = virt_to_pte(NULL, (unsigned long)reboot_code_buffer);
292 __set_pte(ptep, pte_mkexec(*ptep));
293 memcpy(reboot_code_buffer, relocate_new_kernel,
294 relocate_new_kernel_size);
295 __flush_icache_range(
296 (unsigned long) reboot_code_buffer,
297 (unsigned long) reboot_code_buffer + relocate_new_kernel_size);
298
299 setup_quasi_va_is_pa();
300
301 /* now call it */
302 rnk = reboot_code_buffer;
303 (*rnk)(image->head, reboot_code_buffer, image->start);
304 }
305