arch/tile/kernel/machine_kexec.c

   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
  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
  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
  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
  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
 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
 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  */
 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
 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
 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 }