xref: /openbmc/linux/arch/m68k/kernel/sys_m68k.c (revision 5d0e4d78) 
1 /*
2  * linux/arch/m68k/kernel/sys_m68k.c
3  *
4  * This file contains various random system calls that
5  * have a non-standard calling sequence on the Linux/m68k
6  * platform.
7  */
8 
9 #include <linux/capability.h>
10 #include <linux/errno.h>
11 #include <linux/sched.h>
12 #include <linux/mm.h>
13 #include <linux/fs.h>
14 #include <linux/smp.h>
15 #include <linux/sem.h>
16 #include <linux/msg.h>
17 #include <linux/shm.h>
18 #include <linux/stat.h>
19 #include <linux/syscalls.h>
20 #include <linux/mman.h>
21 #include <linux/file.h>
22 #include <linux/ipc.h>
23 
24 #include <asm/setup.h>
25 #include <linux/uaccess.h>
26 #include <asm/cachectl.h>
27 #include <asm/traps.h>
28 #include <asm/page.h>
29 #include <asm/unistd.h>
30 #include <asm/cacheflush.h>
31 
32 #ifdef CONFIG_MMU
33 
34 #include <asm/tlb.h>
35 
36 asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
37 			     unsigned long error_code);
38 
39 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
40 	unsigned long prot, unsigned long flags,
41 	unsigned long fd, unsigned long pgoff)
42 {
43 	/*
44 	 * This is wrong for sun3 - there PAGE_SIZE is 8Kb,
45 	 * so we need to shift the argument down by 1; m68k mmap64(3)
46 	 * (in libc) expects the last argument of mmap2 in 4Kb units.
47 	 */
48 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
49 }
50 
51 /* Convert virtual (user) address VADDR to physical address PADDR */
52 #define virt_to_phys_040(vaddr)						\
53 ({									\
54   unsigned long _mmusr, _paddr;						\
55 									\
56   __asm__ __volatile__ (".chip 68040\n\t"				\
57 			"ptestr (%1)\n\t"				\
58 			"movec %%mmusr,%0\n\t"				\
59 			".chip 68k"					\
60 			: "=r" (_mmusr)					\
61 			: "a" (vaddr));					\
62   _paddr = (_mmusr & MMU_R_040) ? (_mmusr & PAGE_MASK) : 0;		\
63   _paddr;								\
64 })
65 
66 static inline int
67 cache_flush_040 (unsigned long addr, int scope, int cache, unsigned long len)
68 {
69   unsigned long paddr, i;
70 
71   switch (scope)
72     {
73     case FLUSH_SCOPE_ALL:
74       switch (cache)
75 	{
76 	case FLUSH_CACHE_DATA:
77 	  /* This nop is needed for some broken versions of the 68040.  */
78 	  __asm__ __volatile__ ("nop\n\t"
79 				".chip 68040\n\t"
80 				"cpusha %dc\n\t"
81 				".chip 68k");
82 	  break;
83 	case FLUSH_CACHE_INSN:
84 	  __asm__ __volatile__ ("nop\n\t"
85 				".chip 68040\n\t"
86 				"cpusha %ic\n\t"
87 				".chip 68k");
88 	  break;
89 	default:
90 	case FLUSH_CACHE_BOTH:
91 	  __asm__ __volatile__ ("nop\n\t"
92 				".chip 68040\n\t"
93 				"cpusha %bc\n\t"
94 				".chip 68k");
95 	  break;
96 	}
97       break;
98 
99     case FLUSH_SCOPE_LINE:
100       /* Find the physical address of the first mapped page in the
101 	 address range.  */
102       if ((paddr = virt_to_phys_040(addr))) {
103         paddr += addr & ~(PAGE_MASK | 15);
104         len = (len + (addr & 15) + 15) >> 4;
105       } else {
106 	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
107 
108 	if (len <= tmp)
109 	  return 0;
110 	addr += tmp;
111 	len -= tmp;
112 	tmp = PAGE_SIZE;
113 	for (;;)
114 	  {
115 	    if ((paddr = virt_to_phys_040(addr)))
116 	      break;
117 	    if (len <= tmp)
118 	      return 0;
119 	    addr += tmp;
120 	    len -= tmp;
121 	  }
122 	len = (len + 15) >> 4;
123       }
124       i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
125       while (len--)
126 	{
127 	  switch (cache)
128 	    {
129 	    case FLUSH_CACHE_DATA:
130 	      __asm__ __volatile__ ("nop\n\t"
131 				    ".chip 68040\n\t"
132 				    "cpushl %%dc,(%0)\n\t"
133 				    ".chip 68k"
134 				    : : "a" (paddr));
135 	      break;
136 	    case FLUSH_CACHE_INSN:
137 	      __asm__ __volatile__ ("nop\n\t"
138 				    ".chip 68040\n\t"
139 				    "cpushl %%ic,(%0)\n\t"
140 				    ".chip 68k"
141 				    : : "a" (paddr));
142 	      break;
143 	    default:
144 	    case FLUSH_CACHE_BOTH:
145 	      __asm__ __volatile__ ("nop\n\t"
146 				    ".chip 68040\n\t"
147 				    "cpushl %%bc,(%0)\n\t"
148 				    ".chip 68k"
149 				    : : "a" (paddr));
150 	      break;
151 	    }
152 	  if (!--i && len)
153 	    {
154 	      /*
155 	       * No need to page align here since it is done by
156 	       * virt_to_phys_040().
157 	       */
158 	      addr += PAGE_SIZE;
159 	      i = PAGE_SIZE / 16;
160 	      /* Recompute physical address when crossing a page
161 	         boundary. */
162 	      for (;;)
163 		{
164 		  if ((paddr = virt_to_phys_040(addr)))
165 		    break;
166 		  if (len <= i)
167 		    return 0;
168 		  len -= i;
169 		  addr += PAGE_SIZE;
170 		}
171 	    }
172 	  else
173 	    paddr += 16;
174 	}
175       break;
176 
177     default:
178     case FLUSH_SCOPE_PAGE:
179       len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
180       for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
181 	{
182 	  if (!(paddr = virt_to_phys_040(addr)))
183 	    continue;
184 	  switch (cache)
185 	    {
186 	    case FLUSH_CACHE_DATA:
187 	      __asm__ __volatile__ ("nop\n\t"
188 				    ".chip 68040\n\t"
189 				    "cpushp %%dc,(%0)\n\t"
190 				    ".chip 68k"
191 				    : : "a" (paddr));
192 	      break;
193 	    case FLUSH_CACHE_INSN:
194 	      __asm__ __volatile__ ("nop\n\t"
195 				    ".chip 68040\n\t"
196 				    "cpushp %%ic,(%0)\n\t"
197 				    ".chip 68k"
198 				    : : "a" (paddr));
199 	      break;
200 	    default:
201 	    case FLUSH_CACHE_BOTH:
202 	      __asm__ __volatile__ ("nop\n\t"
203 				    ".chip 68040\n\t"
204 				    "cpushp %%bc,(%0)\n\t"
205 				    ".chip 68k"
206 				    : : "a" (paddr));
207 	      break;
208 	    }
209 	}
210       break;
211     }
212   return 0;
213 }
214 
215 #define virt_to_phys_060(vaddr)				\
216 ({							\
217   unsigned long paddr;					\
218   __asm__ __volatile__ (".chip 68060\n\t"		\
219 			"plpar (%0)\n\t"		\
220 			".chip 68k"			\
221 			: "=a" (paddr)			\
222 			: "0" (vaddr));			\
223   (paddr); /* XXX */					\
224 })
225 
226 static inline int
227 cache_flush_060 (unsigned long addr, int scope, int cache, unsigned long len)
228 {
229   unsigned long paddr, i;
230 
231   /*
232    * 68060 manual says:
233    *  cpush %dc : flush DC, remains valid (with our %cacr setup)
234    *  cpush %ic : invalidate IC
235    *  cpush %bc : flush DC + invalidate IC
236    */
237   switch (scope)
238     {
239     case FLUSH_SCOPE_ALL:
240       switch (cache)
241 	{
242 	case FLUSH_CACHE_DATA:
243 	  __asm__ __volatile__ (".chip 68060\n\t"
244 				"cpusha %dc\n\t"
245 				".chip 68k");
246 	  break;
247 	case FLUSH_CACHE_INSN:
248 	  __asm__ __volatile__ (".chip 68060\n\t"
249 				"cpusha %ic\n\t"
250 				".chip 68k");
251 	  break;
252 	default:
253 	case FLUSH_CACHE_BOTH:
254 	  __asm__ __volatile__ (".chip 68060\n\t"
255 				"cpusha %bc\n\t"
256 				".chip 68k");
257 	  break;
258 	}
259       break;
260 
261     case FLUSH_SCOPE_LINE:
262       /* Find the physical address of the first mapped page in the
263 	 address range.  */
264       len += addr & 15;
265       addr &= -16;
266       if (!(paddr = virt_to_phys_060(addr))) {
267 	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
268 
269 	if (len <= tmp)
270 	  return 0;
271 	addr += tmp;
272 	len -= tmp;
273 	tmp = PAGE_SIZE;
274 	for (;;)
275 	  {
276 	    if ((paddr = virt_to_phys_060(addr)))
277 	      break;
278 	    if (len <= tmp)
279 	      return 0;
280 	    addr += tmp;
281 	    len -= tmp;
282 	  }
283       }
284       len = (len + 15) >> 4;
285       i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
286       while (len--)
287 	{
288 	  switch (cache)
289 	    {
290 	    case FLUSH_CACHE_DATA:
291 	      __asm__ __volatile__ (".chip 68060\n\t"
292 				    "cpushl %%dc,(%0)\n\t"
293 				    ".chip 68k"
294 				    : : "a" (paddr));
295 	      break;
296 	    case FLUSH_CACHE_INSN:
297 	      __asm__ __volatile__ (".chip 68060\n\t"
298 				    "cpushl %%ic,(%0)\n\t"
299 				    ".chip 68k"
300 				    : : "a" (paddr));
301 	      break;
302 	    default:
303 	    case FLUSH_CACHE_BOTH:
304 	      __asm__ __volatile__ (".chip 68060\n\t"
305 				    "cpushl %%bc,(%0)\n\t"
306 				    ".chip 68k"
307 				    : : "a" (paddr));
308 	      break;
309 	    }
310 	  if (!--i && len)
311 	    {
312 
313 	      /*
314 	       * We just want to jump to the first cache line
315 	       * in the next page.
316 	       */
317 	      addr += PAGE_SIZE;
318 	      addr &= PAGE_MASK;
319 
320 	      i = PAGE_SIZE / 16;
321 	      /* Recompute physical address when crossing a page
322 	         boundary. */
323 	      for (;;)
324 	        {
325 	          if ((paddr = virt_to_phys_060(addr)))
326 	            break;
327 	          if (len <= i)
328 	            return 0;
329 	          len -= i;
330 	          addr += PAGE_SIZE;
331 	        }
332 	    }
333 	  else
334 	    paddr += 16;
335 	}
336       break;
337 
338     default:
339     case FLUSH_SCOPE_PAGE:
340       len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
341       addr &= PAGE_MASK;	/* Workaround for bug in some
342 				   revisions of the 68060 */
343       for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
344 	{
345 	  if (!(paddr = virt_to_phys_060(addr)))
346 	    continue;
347 	  switch (cache)
348 	    {
349 	    case FLUSH_CACHE_DATA:
350 	      __asm__ __volatile__ (".chip 68060\n\t"
351 				    "cpushp %%dc,(%0)\n\t"
352 				    ".chip 68k"
353 				    : : "a" (paddr));
354 	      break;
355 	    case FLUSH_CACHE_INSN:
356 	      __asm__ __volatile__ (".chip 68060\n\t"
357 				    "cpushp %%ic,(%0)\n\t"
358 				    ".chip 68k"
359 				    : : "a" (paddr));
360 	      break;
361 	    default:
362 	    case FLUSH_CACHE_BOTH:
363 	      __asm__ __volatile__ (".chip 68060\n\t"
364 				    "cpushp %%bc,(%0)\n\t"
365 				    ".chip 68k"
366 				    : : "a" (paddr));
367 	      break;
368 	    }
369 	}
370       break;
371     }
372   return 0;
373 }
374 
375 /* sys_cacheflush -- flush (part of) the processor cache.  */
376 asmlinkage int
377 sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
378 {
379 	int ret = -EINVAL;
380 
381 	if (scope < FLUSH_SCOPE_LINE || scope > FLUSH_SCOPE_ALL ||
382 	    cache & ~FLUSH_CACHE_BOTH)
383 		goto out;
384 
385 	if (scope == FLUSH_SCOPE_ALL) {
386 		/* Only the superuser may explicitly flush the whole cache. */
387 		ret = -EPERM;
388 		if (!capable(CAP_SYS_ADMIN))
389 			goto out;
390 	} else {
391 		struct vm_area_struct *vma;
392 
393 		/* Check for overflow.  */
394 		if (addr + len < addr)
395 			goto out;
396 
397 		/*
398 		 * Verify that the specified address region actually belongs
399 		 * to this process.
400 		 */
401 		down_read(&current->mm->mmap_sem);
402 		vma = find_vma(current->mm, addr);
403 		if (!vma || addr < vma->vm_start || addr + len > vma->vm_end)
404 			goto out_unlock;
405 	}
406 
407 	if (CPU_IS_020_OR_030) {
408 		if (scope == FLUSH_SCOPE_LINE && len < 256) {
409 			unsigned long cacr;
410 			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
411 			if (cache & FLUSH_CACHE_INSN)
412 				cacr |= 4;
413 			if (cache & FLUSH_CACHE_DATA)
414 				cacr |= 0x400;
415 			len >>= 2;
416 			while (len--) {
417 				__asm__ __volatile__ ("movec %1, %%caar\n\t"
418 						      "movec %0, %%cacr"
419 						      : /* no outputs */
420 						      : "r" (cacr), "r" (addr));
421 				addr += 4;
422 			}
423 		} else {
424 			/* Flush the whole cache, even if page granularity requested. */
425 			unsigned long cacr;
426 			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
427 			if (cache & FLUSH_CACHE_INSN)
428 				cacr |= 8;
429 			if (cache & FLUSH_CACHE_DATA)
430 				cacr |= 0x800;
431 			__asm__ __volatile__ ("movec %0, %%cacr" : : "r" (cacr));
432 		}
433 		ret = 0;
434 		goto out_unlock;
435 	} else {
436 	    /*
437 	     * 040 or 060: don't blindly trust 'scope', someone could
438 	     * try to flush a few megs of memory.
439 	     */
440 
441 	    if (len>=3*PAGE_SIZE && scope<FLUSH_SCOPE_PAGE)
442 	        scope=FLUSH_SCOPE_PAGE;
443 	    if (len>=10*PAGE_SIZE && scope<FLUSH_SCOPE_ALL)
444 	        scope=FLUSH_SCOPE_ALL;
445 	    if (CPU_IS_040) {
446 		ret = cache_flush_040 (addr, scope, cache, len);
447 	    } else if (CPU_IS_060) {
448 		ret = cache_flush_060 (addr, scope, cache, len);
449 	    }
450 	}
451 out_unlock:
452 	up_read(&current->mm->mmap_sem);
453 out:
454 	return ret;
455 }
456 
457 /* This syscall gets its arguments in A0 (mem), D2 (oldval) and
458    D1 (newval).  */
459 asmlinkage int
460 sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
461 		      unsigned long __user * mem)
462 {
463 	/* This was borrowed from ARM's implementation.  */
464 	for (;;) {
465 		struct mm_struct *mm = current->mm;
466 		pgd_t *pgd;
467 		pmd_t *pmd;
468 		pte_t *pte;
469 		spinlock_t *ptl;
470 		unsigned long mem_value;
471 
472 		down_read(&mm->mmap_sem);
473 		pgd = pgd_offset(mm, (unsigned long)mem);
474 		if (!pgd_present(*pgd))
475 			goto bad_access;
476 		pmd = pmd_offset(pgd, (unsigned long)mem);
477 		if (!pmd_present(*pmd))
478 			goto bad_access;
479 		pte = pte_offset_map_lock(mm, pmd, (unsigned long)mem, &ptl);
480 		if (!pte_present(*pte) || !pte_dirty(*pte)
481 		    || !pte_write(*pte)) {
482 			pte_unmap_unlock(pte, ptl);
483 			goto bad_access;
484 		}
485 
486 		/*
487 		 * No need to check for EFAULT; we know that the page is
488 		 * present and writable.
489 		 */
490 		__get_user(mem_value, mem);
491 		if (mem_value == oldval)
492 			__put_user(newval, mem);
493 
494 		pte_unmap_unlock(pte, ptl);
495 		up_read(&mm->mmap_sem);
496 		return mem_value;
497 
498 	      bad_access:
499 		up_read(&mm->mmap_sem);
500 		/* This is not necessarily a bad access, we can get here if
501 		   a memory we're trying to write to should be copied-on-write.
502 		   Make the kernel do the necessary page stuff, then re-iterate.
503 		   Simulate a write access fault to do that.  */
504 		{
505 			/* The first argument of the function corresponds to
506 			   D1, which is the first field of struct pt_regs.  */
507 			struct pt_regs *fp = (struct pt_regs *)&newval;
508 
509 			/* '3' is an RMW flag.  */
510 			if (do_page_fault(fp, (unsigned long)mem, 3))
511 				/* If the do_page_fault() failed, we don't
512 				   have anything meaningful to return.
513 				   There should be a SIGSEGV pending for
514 				   the process.  */
515 				return 0xdeadbeef;
516 		}
517 	}
518 }
519 
520 #else
521 
522 /* sys_cacheflush -- flush (part of) the processor cache.  */
523 asmlinkage int
524 sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
525 {
526 	flush_cache_all();
527 	return 0;
528 }
529 
530 /* This syscall gets its arguments in A0 (mem), D2 (oldval) and
531    D1 (newval).  */
532 asmlinkage int
533 sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
534 		      unsigned long __user * mem)
535 {
536 	struct mm_struct *mm = current->mm;
537 	unsigned long mem_value;
538 
539 	down_read(&mm->mmap_sem);
540 
541 	mem_value = *mem;
542 	if (mem_value == oldval)
543 		*mem = newval;
544 
545 	up_read(&mm->mmap_sem);
546 	return mem_value;
547 }
548 
549 #endif /* CONFIG_MMU */
550 
551 asmlinkage int sys_getpagesize(void)
552 {
553 	return PAGE_SIZE;
554 }
555 
556 asmlinkage unsigned long sys_get_thread_area(void)
557 {
558 	return current_thread_info()->tp_value;
559 }
560 
561 asmlinkage int sys_set_thread_area(unsigned long tp)
562 {
563 	current_thread_info()->tp_value = tp;
564 	return 0;
565 }
566 
567 asmlinkage int sys_atomic_barrier(void)
568 {
569 	/* no code needed for uniprocs */
570 	return 0;
571 }
572