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Linux/arch/mips/kernel/vpe.c

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  1 /*
  2  * This file is subject to the terms and conditions of the GNU General Public
  3  * License.  See the file "COPYING" in the main directory of this archive
  4  * for more details.
  5  *
  6  * Copyright (C) 2004, 2005 MIPS Technologies, Inc.  All rights reserved.
  7  * Copyright (C) 2013 Imagination Technologies Ltd.
  8  *
  9  * VPE spport module for loading a MIPS SP program into VPE1. The SP
 10  * environment is rather simple since there are no TLBs. It needs
 11  * to be relocatable (or partiall linked). Initialize your stack in
 12  * the startup-code. The loader looks for the symbol __start and sets
 13  * up the execution to resume from there. To load and run, simply do
 14  * a cat SP 'binary' to the /dev/vpe1 device.
 15  */
 16 #include <linux/kernel.h>
 17 #include <linux/device.h>
 18 #include <linux/fs.h>
 19 #include <linux/init.h>
 20 #include <linux/slab.h>
 21 #include <linux/list.h>
 22 #include <linux/vmalloc.h>
 23 #include <linux/elf.h>
 24 #include <linux/seq_file.h>
 25 #include <linux/syscalls.h>
 26 #include <linux/moduleloader.h>
 27 #include <linux/interrupt.h>
 28 #include <linux/poll.h>
 29 #include <linux/bootmem.h>
 30 #include <asm/mipsregs.h>
 31 #include <asm/mipsmtregs.h>
 32 #include <asm/cacheflush.h>
 33 #include <linux/atomic.h>
 34 #include <asm/mips_mt.h>
 35 #include <asm/processor.h>
 36 #include <asm/vpe.h>
 37 
 38 #ifndef ARCH_SHF_SMALL
 39 #define ARCH_SHF_SMALL 0
 40 #endif
 41 
 42 /* If this is set, the section belongs in the init part of the module */
 43 #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
 44 
 45 struct vpe_control vpecontrol = {
 46         .vpe_list_lock  = __SPIN_LOCK_UNLOCKED(vpe_list_lock),
 47         .vpe_list       = LIST_HEAD_INIT(vpecontrol.vpe_list),
 48         .tc_list_lock   = __SPIN_LOCK_UNLOCKED(tc_list_lock),
 49         .tc_list        = LIST_HEAD_INIT(vpecontrol.tc_list)
 50 };
 51 
 52 /* get the vpe associated with this minor */
 53 struct vpe *get_vpe(int minor)
 54 {
 55         struct vpe *res, *v;
 56 
 57         if (!cpu_has_mipsmt)
 58                 return NULL;
 59 
 60         res = NULL;
 61         spin_lock(&vpecontrol.vpe_list_lock);
 62         list_for_each_entry(v, &vpecontrol.vpe_list, list) {
 63                 if (v->minor == VPE_MODULE_MINOR) {
 64                         res = v;
 65                         break;
 66                 }
 67         }
 68         spin_unlock(&vpecontrol.vpe_list_lock);
 69 
 70         return res;
 71 }
 72 
 73 /* get the vpe associated with this minor */
 74 struct tc *get_tc(int index)
 75 {
 76         struct tc *res, *t;
 77 
 78         res = NULL;
 79         spin_lock(&vpecontrol.tc_list_lock);
 80         list_for_each_entry(t, &vpecontrol.tc_list, list) {
 81                 if (t->index == index) {
 82                         res = t;
 83                         break;
 84                 }
 85         }
 86         spin_unlock(&vpecontrol.tc_list_lock);
 87 
 88         return res;
 89 }
 90 
 91 /* allocate a vpe and associate it with this minor (or index) */
 92 struct vpe *alloc_vpe(int minor)
 93 {
 94         struct vpe *v;
 95 
 96         v = kzalloc(sizeof(struct vpe), GFP_KERNEL);
 97         if (v == NULL)
 98                 goto out;
 99 
100         INIT_LIST_HEAD(&v->tc);
101         spin_lock(&vpecontrol.vpe_list_lock);
102         list_add_tail(&v->list, &vpecontrol.vpe_list);
103         spin_unlock(&vpecontrol.vpe_list_lock);
104 
105         INIT_LIST_HEAD(&v->notify);
106         v->minor = VPE_MODULE_MINOR;
107 
108 out:
109         return v;
110 }
111 
112 /* allocate a tc. At startup only tc0 is running, all other can be halted. */
113 struct tc *alloc_tc(int index)
114 {
115         struct tc *tc;
116 
117         tc = kzalloc(sizeof(struct tc), GFP_KERNEL);
118         if (tc == NULL)
119                 goto out;
120 
121         INIT_LIST_HEAD(&tc->tc);
122         tc->index = index;
123 
124         spin_lock(&vpecontrol.tc_list_lock);
125         list_add_tail(&tc->list, &vpecontrol.tc_list);
126         spin_unlock(&vpecontrol.tc_list_lock);
127 
128 out:
129         return tc;
130 }
131 
132 /* clean up and free everything */
133 void release_vpe(struct vpe *v)
134 {
135         list_del(&v->list);
136         if (v->load_addr)
137                 release_progmem(v);
138         kfree(v);
139 }
140 
141 /* Find some VPE program space */
142 void *alloc_progmem(unsigned long len)
143 {
144         void *addr;
145 
146 #ifdef CONFIG_MIPS_VPE_LOADER_TOM
147         /*
148          * This means you must tell Linux to use less memory than you
149          * physically have, for example by passing a mem= boot argument.
150          */
151         addr = pfn_to_kaddr(max_low_pfn);
152         memset(addr, 0, len);
153 #else
154         /* simple grab some mem for now */
155         addr = kzalloc(len, GFP_KERNEL);
156 #endif
157 
158         return addr;
159 }
160 
161 void release_progmem(void *ptr)
162 {
163 #ifndef CONFIG_MIPS_VPE_LOADER_TOM
164         kfree(ptr);
165 #endif
166 }
167 
168 /* Update size with this section: return offset. */
169 static long get_offset(unsigned long *size, Elf_Shdr *sechdr)
170 {
171         long ret;
172 
173         ret = ALIGN(*size, sechdr->sh_addralign ? : 1);
174         *size = ret + sechdr->sh_size;
175         return ret;
176 }
177 
178 /* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
179    might -- code, read-only data, read-write data, small data.  Tally
180    sizes, and place the offsets into sh_entsize fields: high bit means it
181    belongs in init. */
182 static void layout_sections(struct module *mod, const Elf_Ehdr *hdr,
183                             Elf_Shdr *sechdrs, const char *secstrings)
184 {
185         static unsigned long const masks[][2] = {
186                 /* NOTE: all executable code must be the first section
187                  * in this array; otherwise modify the text_size
188                  * finder in the two loops below */
189                 {SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL},
190                 {SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL},
191                 {SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL},
192                 {ARCH_SHF_SMALL | SHF_ALLOC, 0}
193         };
194         unsigned int m, i;
195 
196         for (i = 0; i < hdr->e_shnum; i++)
197                 sechdrs[i].sh_entsize = ~0UL;
198 
199         for (m = 0; m < ARRAY_SIZE(masks); ++m) {
200                 for (i = 0; i < hdr->e_shnum; ++i) {
201                         Elf_Shdr *s = &sechdrs[i];
202 
203                         if ((s->sh_flags & masks[m][0]) != masks[m][0]
204                             || (s->sh_flags & masks[m][1])
205                             || s->sh_entsize != ~0UL)
206                                 continue;
207                         s->sh_entsize =
208                                 get_offset((unsigned long *)&mod->core_size, s);
209                 }
210 
211                 if (m == 0)
212                         mod->core_text_size = mod->core_size;
213 
214         }
215 }
216 
217 /* from module-elf32.c, but subverted a little */
218 
219 struct mips_hi16 {
220         struct mips_hi16 *next;
221         Elf32_Addr *addr;
222         Elf32_Addr value;
223 };
224 
225 static struct mips_hi16 *mips_hi16_list;
226 static unsigned int gp_offs, gp_addr;
227 
228 static int apply_r_mips_none(struct module *me, uint32_t *location,
229                              Elf32_Addr v)
230 {
231         return 0;
232 }
233 
234 static int apply_r_mips_gprel16(struct module *me, uint32_t *location,
235                                 Elf32_Addr v)
236 {
237         int rel;
238 
239         if (!(*location & 0xffff)) {
240                 rel = (int)v - gp_addr;
241         } else {
242                 /* .sbss + gp(relative) + offset */
243                 /* kludge! */
244                 rel =  (int)(short)((int)v + gp_offs +
245                                     (int)(short)(*location & 0xffff) - gp_addr);
246         }
247 
248         if ((rel > 32768) || (rel < -32768)) {
249                 pr_debug("VPE loader: apply_r_mips_gprel16: relative address 0x%x out of range of gp register\n",
250                          rel);
251                 return -ENOEXEC;
252         }
253 
254         *location = (*location & 0xffff0000) | (rel & 0xffff);
255 
256         return 0;
257 }
258 
259 static int apply_r_mips_pc16(struct module *me, uint32_t *location,
260                              Elf32_Addr v)
261 {
262         int rel;
263         rel = (((unsigned int)v - (unsigned int)location));
264         rel >>= 2; /* because the offset is in _instructions_ not bytes. */
265         rel -= 1;  /* and one instruction less due to the branch delay slot. */
266 
267         if ((rel > 32768) || (rel < -32768)) {
268                 pr_debug("VPE loader: apply_r_mips_pc16: relative address out of range 0x%x\n",
269                          rel);
270                 return -ENOEXEC;
271         }
272 
273         *location = (*location & 0xffff0000) | (rel & 0xffff);
274 
275         return 0;
276 }
277 
278 static int apply_r_mips_32(struct module *me, uint32_t *location,
279                            Elf32_Addr v)
280 {
281         *location += v;
282 
283         return 0;
284 }
285 
286 static int apply_r_mips_26(struct module *me, uint32_t *location,
287                            Elf32_Addr v)
288 {
289         if (v % 4) {
290                 pr_debug("VPE loader: apply_r_mips_26: unaligned relocation\n");
291                 return -ENOEXEC;
292         }
293 
294 /*
295  * Not desperately convinced this is a good check of an overflow condition
296  * anyway. But it gets in the way of handling undefined weak symbols which
297  * we want to set to zero.
298  * if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
299  * printk(KERN_ERR
300  * "module %s: relocation overflow\n",
301  * me->name);
302  * return -ENOEXEC;
303  * }
304  */
305 
306         *location = (*location & ~0x03ffffff) |
307                 ((*location + (v >> 2)) & 0x03ffffff);
308         return 0;
309 }
310 
311 static int apply_r_mips_hi16(struct module *me, uint32_t *location,
312                              Elf32_Addr v)
313 {
314         struct mips_hi16 *n;
315 
316         /*
317          * We cannot relocate this one now because we don't know the value of
318          * the carry we need to add.  Save the information, and let LO16 do the
319          * actual relocation.
320          */
321         n = kmalloc(sizeof(*n), GFP_KERNEL);
322         if (!n)
323                 return -ENOMEM;
324 
325         n->addr = location;
326         n->value = v;
327         n->next = mips_hi16_list;
328         mips_hi16_list = n;
329 
330         return 0;
331 }
332 
333 static int apply_r_mips_lo16(struct module *me, uint32_t *location,
334                              Elf32_Addr v)
335 {
336         unsigned long insnlo = *location;
337         Elf32_Addr val, vallo;
338         struct mips_hi16 *l, *next;
339 
340         /* Sign extend the addend we extract from the lo insn.  */
341         vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
342 
343         if (mips_hi16_list != NULL) {
344 
345                 l = mips_hi16_list;
346                 while (l != NULL) {
347                         unsigned long insn;
348 
349                         /*
350                          * The value for the HI16 had best be the same.
351                          */
352                         if (v != l->value) {
353                                 pr_debug("VPE loader: apply_r_mips_lo16/hi16: inconsistent value information\n");
354                                 goto out_free;
355                         }
356 
357                         /*
358                          * Do the HI16 relocation.  Note that we actually don't
359                          * need to know anything about the LO16 itself, except
360                          * where to find the low 16 bits of the addend needed
361                          * by the LO16.
362                          */
363                         insn = *l->addr;
364                         val = ((insn & 0xffff) << 16) + vallo;
365                         val += v;
366 
367                         /*
368                          * Account for the sign extension that will happen in
369                          * the low bits.
370                          */
371                         val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
372 
373                         insn = (insn & ~0xffff) | val;
374                         *l->addr = insn;
375 
376                         next = l->next;
377                         kfree(l);
378                         l = next;
379                 }
380 
381                 mips_hi16_list = NULL;
382         }
383 
384         /*
385          * Ok, we're done with the HI16 relocs.  Now deal with the LO16.
386          */
387         val = v + vallo;
388         insnlo = (insnlo & ~0xffff) | (val & 0xffff);
389         *location = insnlo;
390 
391         return 0;
392 
393 out_free:
394         while (l != NULL) {
395                 next = l->next;
396                 kfree(l);
397                 l = next;
398         }
399         mips_hi16_list = NULL;
400 
401         return -ENOEXEC;
402 }
403 
404 static int (*reloc_handlers[]) (struct module *me, uint32_t *location,
405                                 Elf32_Addr v) = {
406         [R_MIPS_NONE]   = apply_r_mips_none,
407         [R_MIPS_32]     = apply_r_mips_32,
408         [R_MIPS_26]     = apply_r_mips_26,
409         [R_MIPS_HI16]   = apply_r_mips_hi16,
410         [R_MIPS_LO16]   = apply_r_mips_lo16,
411         [R_MIPS_GPREL16] = apply_r_mips_gprel16,
412         [R_MIPS_PC16] = apply_r_mips_pc16
413 };
414 
415 static char *rstrs[] = {
416         [R_MIPS_NONE]   = "MIPS_NONE",
417         [R_MIPS_32]     = "MIPS_32",
418         [R_MIPS_26]     = "MIPS_26",
419         [R_MIPS_HI16]   = "MIPS_HI16",
420         [R_MIPS_LO16]   = "MIPS_LO16",
421         [R_MIPS_GPREL16] = "MIPS_GPREL16",
422         [R_MIPS_PC16] = "MIPS_PC16"
423 };
424 
425 static int apply_relocations(Elf32_Shdr *sechdrs,
426                       const char *strtab,
427                       unsigned int symindex,
428                       unsigned int relsec,
429                       struct module *me)
430 {
431         Elf32_Rel *rel = (void *) sechdrs[relsec].sh_addr;
432         Elf32_Sym *sym;
433         uint32_t *location;
434         unsigned int i;
435         Elf32_Addr v;
436         int res;
437 
438         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
439                 Elf32_Word r_info = rel[i].r_info;
440 
441                 /* This is where to make the change */
442                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
443                         + rel[i].r_offset;
444                 /* This is the symbol it is referring to */
445                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
446                         + ELF32_R_SYM(r_info);
447 
448                 if (!sym->st_value) {
449                         pr_debug("%s: undefined weak symbol %s\n",
450                                  me->name, strtab + sym->st_name);
451                         /* just print the warning, dont barf */
452                 }
453 
454                 v = sym->st_value;
455 
456                 res = reloc_handlers[ELF32_R_TYPE(r_info)](me, location, v);
457                 if (res) {
458                         char *r = rstrs[ELF32_R_TYPE(r_info)];
459                         pr_warn("VPE loader: .text+0x%x relocation type %s for symbol \"%s\" failed\n",
460                                 rel[i].r_offset, r ? r : "UNKNOWN",
461                                 strtab + sym->st_name);
462                         return res;
463                 }
464         }
465 
466         return 0;
467 }
468 
469 static inline void save_gp_address(unsigned int secbase, unsigned int rel)
470 {
471         gp_addr = secbase + rel;
472         gp_offs = gp_addr - (secbase & 0xffff0000);
473 }
474 /* end module-elf32.c */
475 
476 /* Change all symbols so that sh_value encodes the pointer directly. */
477 static void simplify_symbols(Elf_Shdr *sechdrs,
478                             unsigned int symindex,
479                             const char *strtab,
480                             const char *secstrings,
481                             unsigned int nsecs, struct module *mod)
482 {
483         Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
484         unsigned long secbase, bssbase = 0;
485         unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
486         int size;
487 
488         /* find the .bss section for COMMON symbols */
489         for (i = 0; i < nsecs; i++) {
490                 if (strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) == 0) {
491                         bssbase = sechdrs[i].sh_addr;
492                         break;
493                 }
494         }
495 
496         for (i = 1; i < n; i++) {
497                 switch (sym[i].st_shndx) {
498                 case SHN_COMMON:
499                         /* Allocate space for the symbol in the .bss section.
500                            st_value is currently size.
501                            We want it to have the address of the symbol. */
502 
503                         size = sym[i].st_value;
504                         sym[i].st_value = bssbase;
505 
506                         bssbase += size;
507                         break;
508 
509                 case SHN_ABS:
510                         /* Don't need to do anything */
511                         break;
512 
513                 case SHN_UNDEF:
514                         /* ret = -ENOENT; */
515                         break;
516 
517                 case SHN_MIPS_SCOMMON:
518                         pr_debug("simplify_symbols: ignoring SHN_MIPS_SCOMMON symbol <%s> st_shndx %d\n",
519                                  strtab + sym[i].st_name, sym[i].st_shndx);
520                         /* .sbss section */
521                         break;
522 
523                 default:
524                         secbase = sechdrs[sym[i].st_shndx].sh_addr;
525 
526                         if (strncmp(strtab + sym[i].st_name, "_gp", 3) == 0)
527                                 save_gp_address(secbase, sym[i].st_value);
528 
529                         sym[i].st_value += secbase;
530                         break;
531                 }
532         }
533 }
534 
535 #ifdef DEBUG_ELFLOADER
536 static void dump_elfsymbols(Elf_Shdr *sechdrs, unsigned int symindex,
537                             const char *strtab, struct module *mod)
538 {
539         Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
540         unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
541 
542         pr_debug("dump_elfsymbols: n %d\n", n);
543         for (i = 1; i < n; i++) {
544                 pr_debug(" i %d name <%s> 0x%x\n", i, strtab + sym[i].st_name,
545                          sym[i].st_value);
546         }
547 }
548 #endif
549 
550 static int find_vpe_symbols(struct vpe *v, Elf_Shdr *sechdrs,
551                                       unsigned int symindex, const char *strtab,
552                                       struct module *mod)
553 {
554         Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
555         unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
556 
557         for (i = 1; i < n; i++) {
558                 if (strcmp(strtab + sym[i].st_name, "__start") == 0)
559                         v->__start = sym[i].st_value;
560 
561                 if (strcmp(strtab + sym[i].st_name, "vpe_shared") == 0)
562                         v->shared_ptr = (void *)sym[i].st_value;
563         }
564 
565         if ((v->__start == 0) || (v->shared_ptr == NULL))
566                 return -1;
567 
568         return 0;
569 }
570 
571 /*
572  * Allocates a VPE with some program code space(the load address), copies the
573  * contents of the program (p)buffer performing relocatations/etc, free's it
574  * when finished.
575  */
576 static int vpe_elfload(struct vpe *v)
577 {
578         Elf_Ehdr *hdr;
579         Elf_Shdr *sechdrs;
580         long err = 0;
581         char *secstrings, *strtab = NULL;
582         unsigned int len, i, symindex = 0, strindex = 0, relocate = 0;
583         struct module mod; /* so we can re-use the relocations code */
584 
585         memset(&mod, 0, sizeof(struct module));
586         strcpy(mod.name, "VPE loader");
587 
588         hdr = (Elf_Ehdr *) v->pbuffer;
589         len = v->plen;
590 
591         /* Sanity checks against insmoding binaries or wrong arch,
592            weird elf version */
593         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
594             || (hdr->e_type != ET_REL && hdr->e_type != ET_EXEC)
595             || !elf_check_arch(hdr)
596             || hdr->e_shentsize != sizeof(*sechdrs)) {
597                 pr_warn("VPE loader: program wrong arch or weird elf version\n");
598 
599                 return -ENOEXEC;
600         }
601 
602         if (hdr->e_type == ET_REL)
603                 relocate = 1;
604 
605         if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr)) {
606                 pr_err("VPE loader: program length %u truncated\n", len);
607 
608                 return -ENOEXEC;
609         }
610 
611         /* Convenience variables */
612         sechdrs = (void *)hdr + hdr->e_shoff;
613         secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
614         sechdrs[0].sh_addr = 0;
615 
616         /* And these should exist, but gcc whinges if we don't init them */
617         symindex = strindex = 0;
618 
619         if (relocate) {
620                 for (i = 1; i < hdr->e_shnum; i++) {
621                         if ((sechdrs[i].sh_type != SHT_NOBITS) &&
622                             (len < sechdrs[i].sh_offset + sechdrs[i].sh_size)) {
623                                 pr_err("VPE program length %u truncated\n",
624                                        len);
625                                 return -ENOEXEC;
626                         }
627 
628                         /* Mark all sections sh_addr with their address in the
629                            temporary image. */
630                         sechdrs[i].sh_addr = (size_t) hdr +
631                                 sechdrs[i].sh_offset;
632 
633                         /* Internal symbols and strings. */
634                         if (sechdrs[i].sh_type == SHT_SYMTAB) {
635                                 symindex = i;
636                                 strindex = sechdrs[i].sh_link;
637                                 strtab = (char *)hdr +
638                                         sechdrs[strindex].sh_offset;
639                         }
640                 }
641                 layout_sections(&mod, hdr, sechdrs, secstrings);
642         }
643 
644         v->load_addr = alloc_progmem(mod.core_size);
645         if (!v->load_addr)
646                 return -ENOMEM;
647 
648         pr_info("VPE loader: loading to %p\n", v->load_addr);
649 
650         if (relocate) {
651                 for (i = 0; i < hdr->e_shnum; i++) {
652                         void *dest;
653 
654                         if (!(sechdrs[i].sh_flags & SHF_ALLOC))
655                                 continue;
656 
657                         dest = v->load_addr + sechdrs[i].sh_entsize;
658 
659                         if (sechdrs[i].sh_type != SHT_NOBITS)
660                                 memcpy(dest, (void *)sechdrs[i].sh_addr,
661                                        sechdrs[i].sh_size);
662                         /* Update sh_addr to point to copy in image. */
663                         sechdrs[i].sh_addr = (unsigned long)dest;
664 
665                         pr_debug(" section sh_name %s sh_addr 0x%x\n",
666                                  secstrings + sechdrs[i].sh_name,
667                                  sechdrs[i].sh_addr);
668                 }
669 
670                 /* Fix up syms, so that st_value is a pointer to location. */
671                 simplify_symbols(sechdrs, symindex, strtab, secstrings,
672                                  hdr->e_shnum, &mod);
673 
674                 /* Now do relocations. */
675                 for (i = 1; i < hdr->e_shnum; i++) {
676                         const char *strtab = (char *)sechdrs[strindex].sh_addr;
677                         unsigned int info = sechdrs[i].sh_info;
678 
679                         /* Not a valid relocation section? */
680                         if (info >= hdr->e_shnum)
681                                 continue;
682 
683                         /* Don't bother with non-allocated sections */
684                         if (!(sechdrs[info].sh_flags & SHF_ALLOC))
685                                 continue;
686 
687                         if (sechdrs[i].sh_type == SHT_REL)
688                                 err = apply_relocations(sechdrs, strtab,
689                                                         symindex, i, &mod);
690                         else if (sechdrs[i].sh_type == SHT_RELA)
691                                 err = apply_relocate_add(sechdrs, strtab,
692                                                          symindex, i, &mod);
693                         if (err < 0)
694                                 return err;
695 
696                 }
697         } else {
698                 struct elf_phdr *phdr = (struct elf_phdr *)
699                                                 ((char *)hdr + hdr->e_phoff);
700 
701                 for (i = 0; i < hdr->e_phnum; i++) {
702                         if (phdr->p_type == PT_LOAD) {
703                                 memcpy((void *)phdr->p_paddr,
704                                        (char *)hdr + phdr->p_offset,
705                                        phdr->p_filesz);
706                                 memset((void *)phdr->p_paddr + phdr->p_filesz,
707                                        0, phdr->p_memsz - phdr->p_filesz);
708                     }
709                     phdr++;
710                 }
711 
712                 for (i = 0; i < hdr->e_shnum; i++) {
713                         /* Internal symbols and strings. */
714                         if (sechdrs[i].sh_type == SHT_SYMTAB) {
715                                 symindex = i;
716                                 strindex = sechdrs[i].sh_link;
717                                 strtab = (char *)hdr +
718                                         sechdrs[strindex].sh_offset;
719 
720                                 /*
721                                  * mark symtab's address for when we try
722                                  * to find the magic symbols
723                                  */
724                                 sechdrs[i].sh_addr = (size_t) hdr +
725                                         sechdrs[i].sh_offset;
726                         }
727                 }
728         }
729 
730         /* make sure it's physically written out */
731         flush_icache_range((unsigned long)v->load_addr,
732                            (unsigned long)v->load_addr + v->len);
733 
734         if ((find_vpe_symbols(v, sechdrs, symindex, strtab, &mod)) < 0) {
735                 if (v->__start == 0) {
736                         pr_warn("VPE loader: program does not contain a __start symbol\n");
737                         return -ENOEXEC;
738                 }
739 
740                 if (v->shared_ptr == NULL)
741                         pr_warn("VPE loader: program does not contain vpe_shared symbol.\n"
742                                 " Unable to use AMVP (AP/SP) facilities.\n");
743         }
744 
745         pr_info(" elf loaded\n");
746         return 0;
747 }
748 
749 static int getcwd(char *buff, int size)
750 {
751         mm_segment_t old_fs;
752         int ret;
753 
754         old_fs = get_fs();
755         set_fs(KERNEL_DS);
756 
757         ret = sys_getcwd(buff, size);
758 
759         set_fs(old_fs);
760 
761         return ret;
762 }
763 
764 /* checks VPE is unused and gets ready to load program  */
765 static int vpe_open(struct inode *inode, struct file *filp)
766 {
767         enum vpe_state state;
768         struct vpe_notifications *notifier;
769         struct vpe *v;
770         int ret;
771 
772         if (VPE_MODULE_MINOR != iminor(inode)) {
773                 /* assume only 1 device at the moment. */
774                 pr_warn("VPE loader: only vpe1 is supported\n");
775 
776                 return -ENODEV;
777         }
778 
779         v = get_vpe(aprp_cpu_index());
780         if (v == NULL) {
781                 pr_warn("VPE loader: unable to get vpe\n");
782 
783                 return -ENODEV;
784         }
785 
786         state = xchg(&v->state, VPE_STATE_INUSE);
787         if (state != VPE_STATE_UNUSED) {
788                 pr_debug("VPE loader: tc in use dumping regs\n");
789 
790                 list_for_each_entry(notifier, &v->notify, list)
791                         notifier->stop(aprp_cpu_index());
792 
793                 release_progmem(v->load_addr);
794                 cleanup_tc(get_tc(aprp_cpu_index()));
795         }
796 
797         /* this of-course trashes what was there before... */
798         v->pbuffer = vmalloc(P_SIZE);
799         if (!v->pbuffer) {
800                 pr_warn("VPE loader: unable to allocate memory\n");
801                 return -ENOMEM;
802         }
803         v->plen = P_SIZE;
804         v->load_addr = NULL;
805         v->len = 0;
806 
807         v->cwd[0] = 0;
808         ret = getcwd(v->cwd, VPE_PATH_MAX);
809         if (ret < 0)
810                 pr_warn("VPE loader: open, getcwd returned %d\n", ret);
811 
812         v->shared_ptr = NULL;
813         v->__start = 0;
814 
815         return 0;
816 }
817 
818 static int vpe_release(struct inode *inode, struct file *filp)
819 {
820         struct vpe *v;
821         Elf_Ehdr *hdr;
822         int ret = 0;
823 
824         v = get_vpe(aprp_cpu_index());
825         if (v == NULL)
826                 return -ENODEV;
827 
828         hdr = (Elf_Ehdr *) v->pbuffer;
829         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) == 0) {
830                 if ((vpe_elfload(v) >= 0) && vpe_run) {
831                         vpe_run(v);
832                 } else {
833                         pr_warn("VPE loader: ELF load failed.\n");
834                         ret = -ENOEXEC;
835                 }
836         } else {
837                 pr_warn("VPE loader: only elf files are supported\n");
838                 ret = -ENOEXEC;
839         }
840 
841         /* It's good to be able to run the SP and if it chokes have a look at
842            the /dev/rt?. But if we reset the pointer to the shared struct we
843            lose what has happened. So perhaps if garbage is sent to the vpe
844            device, use it as a trigger for the reset. Hopefully a nice
845            executable will be along shortly. */
846         if (ret < 0)
847                 v->shared_ptr = NULL;
848 
849         vfree(v->pbuffer);
850         v->plen = 0;
851 
852         return ret;
853 }
854 
855 static ssize_t vpe_write(struct file *file, const char __user *buffer,
856                          size_t count, loff_t *ppos)
857 {
858         size_t ret = count;
859         struct vpe *v;
860 
861         if (iminor(file_inode(file)) != VPE_MODULE_MINOR)
862                 return -ENODEV;
863 
864         v = get_vpe(aprp_cpu_index());
865 
866         if (v == NULL)
867                 return -ENODEV;
868 
869         if ((count + v->len) > v->plen) {
870                 pr_warn("VPE loader: elf size too big. Perhaps strip uneeded symbols\n");
871                 return -ENOMEM;
872         }
873 
874         count -= copy_from_user(v->pbuffer + v->len, buffer, count);
875         if (!count)
876                 return -EFAULT;
877 
878         v->len += count;
879         return ret;
880 }
881 
882 const struct file_operations vpe_fops = {
883         .owner = THIS_MODULE,
884         .open = vpe_open,
885         .release = vpe_release,
886         .write = vpe_write,
887         .llseek = noop_llseek,
888 };
889 
890 void *vpe_get_shared(int index)
891 {
892         struct vpe *v = get_vpe(index);
893 
894         if (v == NULL)
895                 return NULL;
896 
897         return v->shared_ptr;
898 }
899 EXPORT_SYMBOL(vpe_get_shared);
900 
901 int vpe_notify(int index, struct vpe_notifications *notify)
902 {
903         struct vpe *v = get_vpe(index);
904 
905         if (v == NULL)
906                 return -1;
907 
908         list_add(&notify->list, &v->notify);
909         return 0;
910 }
911 EXPORT_SYMBOL(vpe_notify);
912 
913 char *vpe_getcwd(int index)
914 {
915         struct vpe *v = get_vpe(index);
916 
917         if (v == NULL)
918                 return NULL;
919 
920         return v->cwd;
921 }
922 EXPORT_SYMBOL(vpe_getcwd);
923 
924 module_init(vpe_module_init);
925 module_exit(vpe_module_exit);
926 MODULE_DESCRIPTION("MIPS VPE Loader");
927 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
928 MODULE_LICENSE("GPL");
929 

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