xref: /linux/arch/m68k/kernel/sys_m68k.c (revision cc4589ebfae6f8dbb5cf880a0a67eedab3416492) 
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/smp_lock.h>
16 #include <linux/sem.h>
17 #include <linux/msg.h>
18 #include <linux/shm.h>
19 #include <linux/stat.h>
20 #include <linux/syscalls.h>
21 #include <linux/mman.h>
22 #include <linux/file.h>
23 #include <linux/ipc.h>
24 
25 #include <asm/setup.h>
26 #include <asm/uaccess.h>
27 #include <asm/cachectl.h>
28 #include <asm/traps.h>
29 #include <asm/page.h>
30 #include <asm/unistd.h>
31 #include <linux/elf.h>
32 #include <asm/tlb.h>
33 
34 asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
35 			     unsigned long error_code);
36 
37 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
38 	unsigned long prot, unsigned long flags,
39 	unsigned long fd, unsigned long pgoff)
40 {
41 	/*
42 	 * This is wrong for sun3 - there PAGE_SIZE is 8Kb,
43 	 * so we need to shift the argument down by 1; m68k mmap64(3)
44 	 * (in libc) expects the last argument of mmap2 in 4Kb units.
45 	 */
46 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
47 }
48 
49 /* Convert virtual (user) address VADDR to physical address PADDR */
50 #define virt_to_phys_040(vaddr)						\
51 ({									\
52   unsigned long _mmusr, _paddr;						\
53 									\
54   __asm__ __volatile__ (".chip 68040\n\t"				\
55 			"ptestr (%1)\n\t"				\
56 			"movec %%mmusr,%0\n\t"				\
57 			".chip 68k"					\
58 			: "=r" (_mmusr)					\
59 			: "a" (vaddr));					\
60   _paddr = (_mmusr & MMU_R_040) ? (_mmusr & PAGE_MASK) : 0;		\
61   _paddr;								\
62 })
63 
64 static inline int
65 cache_flush_040 (unsigned long addr, int scope, int cache, unsigned long len)
66 {
67   unsigned long paddr, i;
68 
69   switch (scope)
70     {
71     case FLUSH_SCOPE_ALL:
72       switch (cache)
73 	{
74 	case FLUSH_CACHE_DATA:
75 	  /* This nop is needed for some broken versions of the 68040.  */
76 	  __asm__ __volatile__ ("nop\n\t"
77 				".chip 68040\n\t"
78 				"cpusha %dc\n\t"
79 				".chip 68k");
80 	  break;
81 	case FLUSH_CACHE_INSN:
82 	  __asm__ __volatile__ ("nop\n\t"
83 				".chip 68040\n\t"
84 				"cpusha %ic\n\t"
85 				".chip 68k");
86 	  break;
87 	default:
88 	case FLUSH_CACHE_BOTH:
89 	  __asm__ __volatile__ ("nop\n\t"
90 				".chip 68040\n\t"
91 				"cpusha %bc\n\t"
92 				".chip 68k");
93 	  break;
94 	}
95       break;
96 
97     case FLUSH_SCOPE_LINE:
98       /* Find the physical address of the first mapped page in the
99 	 address range.  */
100       if ((paddr = virt_to_phys_040(addr))) {
101         paddr += addr & ~(PAGE_MASK | 15);
102         len = (len + (addr & 15) + 15) >> 4;
103       } else {
104 	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
105 
106 	if (len <= tmp)
107 	  return 0;
108 	addr += tmp;
109 	len -= tmp;
110 	tmp = PAGE_SIZE;
111 	for (;;)
112 	  {
113 	    if ((paddr = virt_to_phys_040(addr)))
114 	      break;
115 	    if (len <= tmp)
116 	      return 0;
117 	    addr += tmp;
118 	    len -= tmp;
119 	  }
120 	len = (len + 15) >> 4;
121       }
122       i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
123       while (len--)
124 	{
125 	  switch (cache)
126 	    {
127 	    case FLUSH_CACHE_DATA:
128 	      __asm__ __volatile__ ("nop\n\t"
129 				    ".chip 68040\n\t"
130 				    "cpushl %%dc,(%0)\n\t"
131 				    ".chip 68k"
132 				    : : "a" (paddr));
133 	      break;
134 	    case FLUSH_CACHE_INSN:
135 	      __asm__ __volatile__ ("nop\n\t"
136 				    ".chip 68040\n\t"
137 				    "cpushl %%ic,(%0)\n\t"
138 				    ".chip 68k"
139 				    : : "a" (paddr));
140 	      break;
141 	    default:
142 	    case FLUSH_CACHE_BOTH:
143 	      __asm__ __volatile__ ("nop\n\t"
144 				    ".chip 68040\n\t"
145 				    "cpushl %%bc,(%0)\n\t"
146 				    ".chip 68k"
147 				    : : "a" (paddr));
148 	      break;
149 	    }
150 	  if (!--i && len)
151 	    {
152 	      /*
153 	       * No need to page align here since it is done by
154 	       * virt_to_phys_040().
155 	       */
156 	      addr += PAGE_SIZE;
157 	      i = PAGE_SIZE / 16;
158 	      /* Recompute physical address when crossing a page
159 	         boundary. */
160 	      for (;;)
161 		{
162 		  if ((paddr = virt_to_phys_040(addr)))
163 		    break;
164 		  if (len <= i)
165 		    return 0;
166 		  len -= i;
167 		  addr += PAGE_SIZE;
168 		}
169 	    }
170 	  else
171 	    paddr += 16;
172 	}
173       break;
174 
175     default:
176     case FLUSH_SCOPE_PAGE:
177       len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
178       for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
179 	{
180 	  if (!(paddr = virt_to_phys_040(addr)))
181 	    continue;
182 	  switch (cache)
183 	    {
184 	    case FLUSH_CACHE_DATA:
185 	      __asm__ __volatile__ ("nop\n\t"
186 				    ".chip 68040\n\t"
187 				    "cpushp %%dc,(%0)\n\t"
188 				    ".chip 68k"
189 				    : : "a" (paddr));
190 	      break;
191 	    case FLUSH_CACHE_INSN:
192 	      __asm__ __volatile__ ("nop\n\t"
193 				    ".chip 68040\n\t"
194 				    "cpushp %%ic,(%0)\n\t"
195 				    ".chip 68k"
196 				    : : "a" (paddr));
197 	      break;
198 	    default:
199 	    case FLUSH_CACHE_BOTH:
200 	      __asm__ __volatile__ ("nop\n\t"
201 				    ".chip 68040\n\t"
202 				    "cpushp %%bc,(%0)\n\t"
203 				    ".chip 68k"
204 				    : : "a" (paddr));
205 	      break;
206 	    }
207 	}
208       break;
209     }
210   return 0;
211 }
212 
213 #define virt_to_phys_060(vaddr)				\
214 ({							\
215   unsigned long paddr;					\
216   __asm__ __volatile__ (".chip 68060\n\t"		\
217 			"plpar (%0)\n\t"		\
218 			".chip 68k"			\
219 			: "=a" (paddr)			\
220 			: "0" (vaddr));			\
221   (paddr); /* XXX */					\
222 })
223 
224 static inline int
225 cache_flush_060 (unsigned long addr, int scope, int cache, unsigned long len)
226 {
227   unsigned long paddr, i;
228 
229   /*
230    * 68060 manual says:
231    *  cpush %dc : flush DC, remains valid (with our %cacr setup)
232    *  cpush %ic : invalidate IC
233    *  cpush %bc : flush DC + invalidate IC
234    */
235   switch (scope)
236     {
237     case FLUSH_SCOPE_ALL:
238       switch (cache)
239 	{
240 	case FLUSH_CACHE_DATA:
241 	  __asm__ __volatile__ (".chip 68060\n\t"
242 				"cpusha %dc\n\t"
243 				".chip 68k");
244 	  break;
245 	case FLUSH_CACHE_INSN:
246 	  __asm__ __volatile__ (".chip 68060\n\t"
247 				"cpusha %ic\n\t"
248 				".chip 68k");
249 	  break;
250 	default:
251 	case FLUSH_CACHE_BOTH:
252 	  __asm__ __volatile__ (".chip 68060\n\t"
253 				"cpusha %bc\n\t"
254 				".chip 68k");
255 	  break;
256 	}
257       break;
258 
259     case FLUSH_SCOPE_LINE:
260       /* Find the physical address of the first mapped page in the
261 	 address range.  */
262       len += addr & 15;
263       addr &= -16;
264       if (!(paddr = virt_to_phys_060(addr))) {
265 	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
266 
267 	if (len <= tmp)
268 	  return 0;
269 	addr += tmp;
270 	len -= tmp;
271 	tmp = PAGE_SIZE;
272 	for (;;)
273 	  {
274 	    if ((paddr = virt_to_phys_060(addr)))
275 	      break;
276 	    if (len <= tmp)
277 	      return 0;
278 	    addr += tmp;
279 	    len -= tmp;
280 	  }
281       }
282       len = (len + 15) >> 4;
283       i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
284       while (len--)
285 	{
286 	  switch (cache)
287 	    {
288 	    case FLUSH_CACHE_DATA:
289 	      __asm__ __volatile__ (".chip 68060\n\t"
290 				    "cpushl %%dc,(%0)\n\t"
291 				    ".chip 68k"
292 				    : : "a" (paddr));
293 	      break;
294 	    case FLUSH_CACHE_INSN:
295 	      __asm__ __volatile__ (".chip 68060\n\t"
296 				    "cpushl %%ic,(%0)\n\t"
297 				    ".chip 68k"
298 				    : : "a" (paddr));
299 	      break;
300 	    default:
301 	    case FLUSH_CACHE_BOTH:
302 	      __asm__ __volatile__ (".chip 68060\n\t"
303 				    "cpushl %%bc,(%0)\n\t"
304 				    ".chip 68k"
305 				    : : "a" (paddr));
306 	      break;
307 	    }
308 	  if (!--i && len)
309 	    {
310 
311 	      /*
312 	       * We just want to jump to the first cache line
313 	       * in the next page.
314 	       */
315 	      addr += PAGE_SIZE;
316 	      addr &= PAGE_MASK;
317 
318 	      i = PAGE_SIZE / 16;
319 	      /* Recompute physical address when crossing a page
320 	         boundary. */
321 	      for (;;)
322 	        {
323 	          if ((paddr = virt_to_phys_060(addr)))
324 	            break;
325 	          if (len <= i)
326 	            return 0;
327 	          len -= i;
328 	          addr += PAGE_SIZE;
329 	        }
330 	    }
331 	  else
332 	    paddr += 16;
333 	}
334       break;
335 
336     default:
337     case FLUSH_SCOPE_PAGE:
338       len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
339       addr &= PAGE_MASK;	/* Workaround for bug in some
340 				   revisions of the 68060 */
341       for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
342 	{
343 	  if (!(paddr = virt_to_phys_060(addr)))
344 	    continue;
345 	  switch (cache)
346 	    {
347 	    case FLUSH_CACHE_DATA:
348 	      __asm__ __volatile__ (".chip 68060\n\t"
349 				    "cpushp %%dc,(%0)\n\t"
350 				    ".chip 68k"
351 				    : : "a" (paddr));
352 	      break;
353 	    case FLUSH_CACHE_INSN:
354 	      __asm__ __volatile__ (".chip 68060\n\t"
355 				    "cpushp %%ic,(%0)\n\t"
356 				    ".chip 68k"
357 				    : : "a" (paddr));
358 	      break;
359 	    default:
360 	    case FLUSH_CACHE_BOTH:
361 	      __asm__ __volatile__ (".chip 68060\n\t"
362 				    "cpushp %%bc,(%0)\n\t"
363 				    ".chip 68k"
364 				    : : "a" (paddr));
365 	      break;
366 	    }
367 	}
368       break;
369     }
370   return 0;
371 }
372 
373 /* sys_cacheflush -- flush (part of) the processor cache.  */
374 asmlinkage int
375 sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
376 {
377 	struct vm_area_struct *vma;
378 	int ret = -EINVAL;
379 
380 	lock_kernel();
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 		/*
392 		 * Verify that the specified address region actually belongs
393 		 * to this process.
394 		 */
395 		vma = find_vma (current->mm, addr);
396 		ret = -EINVAL;
397 		/* Check for overflow.  */
398 		if (addr + len < addr)
399 			goto out;
400 		if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end)
401 			goto out;
402 	}
403 
404 	if (CPU_IS_020_OR_030) {
405 		if (scope == FLUSH_SCOPE_LINE && len < 256) {
406 			unsigned long cacr;
407 			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
408 			if (cache & FLUSH_CACHE_INSN)
409 				cacr |= 4;
410 			if (cache & FLUSH_CACHE_DATA)
411 				cacr |= 0x400;
412 			len >>= 2;
413 			while (len--) {
414 				__asm__ __volatile__ ("movec %1, %%caar\n\t"
415 						      "movec %0, %%cacr"
416 						      : /* no outputs */
417 						      : "r" (cacr), "r" (addr));
418 				addr += 4;
419 			}
420 		} else {
421 			/* Flush the whole cache, even if page granularity requested. */
422 			unsigned long cacr;
423 			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
424 			if (cache & FLUSH_CACHE_INSN)
425 				cacr |= 8;
426 			if (cache & FLUSH_CACHE_DATA)
427 				cacr |= 0x800;
428 			__asm__ __volatile__ ("movec %0, %%cacr" : : "r" (cacr));
429 		}
430 		ret = 0;
431 		goto out;
432 	} else {
433 	    /*
434 	     * 040 or 060: don't blindly trust 'scope', someone could
435 	     * try to flush a few megs of memory.
436 	     */
437 
438 	    if (len>=3*PAGE_SIZE && scope<FLUSH_SCOPE_PAGE)
439 	        scope=FLUSH_SCOPE_PAGE;
440 	    if (len>=10*PAGE_SIZE && scope<FLUSH_SCOPE_ALL)
441 	        scope=FLUSH_SCOPE_ALL;
442 	    if (CPU_IS_040) {
443 		ret = cache_flush_040 (addr, scope, cache, len);
444 	    } else if (CPU_IS_060) {
445 		ret = cache_flush_060 (addr, scope, cache, len);
446 	    }
447 	}
448 out:
449 	unlock_kernel();
450 	return ret;
451 }
452 
453 asmlinkage int sys_getpagesize(void)
454 {
455 	return PAGE_SIZE;
456 }
457 
458 /*
459  * Do a system call from kernel instead of calling sys_execve so we
460  * end up with proper pt_regs.
461  */
462 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
463 {
464 	register long __res asm ("%d0") = __NR_execve;
465 	register long __a asm ("%d1") = (long)(filename);
466 	register long __b asm ("%d2") = (long)(argv);
467 	register long __c asm ("%d3") = (long)(envp);
468 	asm volatile ("trap  #0" : "+d" (__res)
469 			: "d" (__a), "d" (__b), "d" (__c));
470 	return __res;
471 }
472 
473 asmlinkage unsigned long sys_get_thread_area(void)
474 {
475 	return current_thread_info()->tp_value;
476 }
477 
478 asmlinkage int sys_set_thread_area(unsigned long tp)
479 {
480 	current_thread_info()->tp_value = tp;
481 	return 0;
482 }
483 
484 /* This syscall gets its arguments in A0 (mem), D2 (oldval) and
485    D1 (newval).  */
486 asmlinkage int
487 sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
488 		      unsigned long __user * mem)
489 {
490 	/* This was borrowed from ARM's implementation.  */
491 	for (;;) {
492 		struct mm_struct *mm = current->mm;
493 		pgd_t *pgd;
494 		pmd_t *pmd;
495 		pte_t *pte;
496 		spinlock_t *ptl;
497 		unsigned long mem_value;
498 
499 		down_read(&mm->mmap_sem);
500 		pgd = pgd_offset(mm, (unsigned long)mem);
501 		if (!pgd_present(*pgd))
502 			goto bad_access;
503 		pmd = pmd_offset(pgd, (unsigned long)mem);
504 		if (!pmd_present(*pmd))
505 			goto bad_access;
506 		pte = pte_offset_map_lock(mm, pmd, (unsigned long)mem, &ptl);
507 		if (!pte_present(*pte) || !pte_dirty(*pte)
508 		    || !pte_write(*pte)) {
509 			pte_unmap_unlock(pte, ptl);
510 			goto bad_access;
511 		}
512 
513 		mem_value = *mem;
514 		if (mem_value == oldval)
515 			*mem = newval;
516 
517 		pte_unmap_unlock(pte, ptl);
518 		up_read(&mm->mmap_sem);
519 		return mem_value;
520 
521 	      bad_access:
522 		up_read(&mm->mmap_sem);
523 		/* This is not necessarily a bad access, we can get here if
524 		   a memory we're trying to write to should be copied-on-write.
525 		   Make the kernel do the necessary page stuff, then re-iterate.
526 		   Simulate a write access fault to do that.  */
527 		{
528 			/* The first argument of the function corresponds to
529 			   D1, which is the first field of struct pt_regs.  */
530 			struct pt_regs *fp = (struct pt_regs *)&newval;
531 
532 			/* '3' is an RMW flag.  */
533 			if (do_page_fault(fp, (unsigned long)mem, 3))
534 				/* If the do_page_fault() failed, we don't
535 				   have anything meaningful to return.
536 				   There should be a SIGSEGV pending for
537 				   the process.  */
538 				return 0xdeadbeef;
539 		}
540 	}
541 }
542 
543 asmlinkage int sys_atomic_barrier(void)
544 {
545 	/* no code needed for uniprocs */
546 	return 0;
547 }
548