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