xref: /openbmc/linux/arch/m68k/kernel/sys_m68k.c (revision 65417d9f) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/arch/m68k/kernel/sys_m68k.c
4  *
5  * This file contains various random system calls that
6  * have a non-standard calling sequence on the Linux/m68k
7  * platform.
8  */
9 
10 #include <linux/capability.h>
11 #include <linux/errno.h>
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/fs.h>
15 #include <linux/smp.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 <linux/uaccess.h>
27 #include <asm/cachectl.h>
28 #include <asm/traps.h>
29 #include <asm/page.h>
30 #include <asm/unistd.h>
31 #include <asm/cacheflush.h>
32 
33 #ifdef CONFIG_MMU
34 
35 #include <asm/tlb.h>
36 
37 asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
38 			     unsigned long error_code);
39 
40 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
41 	unsigned long prot, unsigned long flags,
42 	unsigned long fd, unsigned long pgoff)
43 {
44 	/*
45 	 * This is wrong for sun3 - there PAGE_SIZE is 8Kb,
46 	 * so we need to shift the argument down by 1; m68k mmap64(3)
47 	 * (in libc) expects the last argument of mmap2 in 4Kb units.
48 	 */
49 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
50 }
51 
52 /* Convert virtual (user) address VADDR to physical address PADDR */
53 #define virt_to_phys_040(vaddr)						\
54 ({									\
55   unsigned long _mmusr, _paddr;						\
56 									\
57   __asm__ __volatile__ (".chip 68040\n\t"				\
58 			"ptestr (%1)\n\t"				\
59 			"movec %%mmusr,%0\n\t"				\
60 			".chip 68k"					\
61 			: "=r" (_mmusr)					\
62 			: "a" (vaddr));					\
63   _paddr = (_mmusr & MMU_R_040) ? (_mmusr & PAGE_MASK) : 0;		\
64   _paddr;								\
65 })
66 
67 static inline int
68 cache_flush_040 (unsigned long addr, int scope, int cache, unsigned long len)
69 {
70   unsigned long paddr, i;
71 
72   switch (scope)
73     {
74     case FLUSH_SCOPE_ALL:
75       switch (cache)
76 	{
77 	case FLUSH_CACHE_DATA:
78 	  /* This nop is needed for some broken versions of the 68040.  */
79 	  __asm__ __volatile__ ("nop\n\t"
80 				".chip 68040\n\t"
81 				"cpusha %dc\n\t"
82 				".chip 68k");
83 	  break;
84 	case FLUSH_CACHE_INSN:
85 	  __asm__ __volatile__ ("nop\n\t"
86 				".chip 68040\n\t"
87 				"cpusha %ic\n\t"
88 				".chip 68k");
89 	  break;
90 	default:
91 	case FLUSH_CACHE_BOTH:
92 	  __asm__ __volatile__ ("nop\n\t"
93 				".chip 68040\n\t"
94 				"cpusha %bc\n\t"
95 				".chip 68k");
96 	  break;
97 	}
98       break;
99 
100     case FLUSH_SCOPE_LINE:
101       /* Find the physical address of the first mapped page in the
102 	 address range.  */
103       if ((paddr = virt_to_phys_040(addr))) {
104         paddr += addr & ~(PAGE_MASK | 15);
105         len = (len + (addr & 15) + 15) >> 4;
106       } else {
107 	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
108 
109 	if (len <= tmp)
110 	  return 0;
111 	addr += tmp;
112 	len -= tmp;
113 	tmp = PAGE_SIZE;
114 	for (;;)
115 	  {
116 	    if ((paddr = virt_to_phys_040(addr)))
117 	      break;
118 	    if (len <= tmp)
119 	      return 0;
120 	    addr += tmp;
121 	    len -= tmp;
122 	  }
123 	len = (len + 15) >> 4;
124       }
125       i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
126       while (len--)
127 	{
128 	  switch (cache)
129 	    {
130 	    case FLUSH_CACHE_DATA:
131 	      __asm__ __volatile__ ("nop\n\t"
132 				    ".chip 68040\n\t"
133 				    "cpushl %%dc,(%0)\n\t"
134 				    ".chip 68k"
135 				    : : "a" (paddr));
136 	      break;
137 	    case FLUSH_CACHE_INSN:
138 	      __asm__ __volatile__ ("nop\n\t"
139 				    ".chip 68040\n\t"
140 				    "cpushl %%ic,(%0)\n\t"
141 				    ".chip 68k"
142 				    : : "a" (paddr));
143 	      break;
144 	    default:
145 	    case FLUSH_CACHE_BOTH:
146 	      __asm__ __volatile__ ("nop\n\t"
147 				    ".chip 68040\n\t"
148 				    "cpushl %%bc,(%0)\n\t"
149 				    ".chip 68k"
150 				    : : "a" (paddr));
151 	      break;
152 	    }
153 	  if (!--i && len)
154 	    {
155 	      /*
156 	       * No need to page align here since it is done by
157 	       * virt_to_phys_040().
158 	       */
159 	      addr += PAGE_SIZE;
160 	      i = PAGE_SIZE / 16;
161 	      /* Recompute physical address when crossing a page
162 	         boundary. */
163 	      for (;;)
164 		{
165 		  if ((paddr = virt_to_phys_040(addr)))
166 		    break;
167 		  if (len <= i)
168 		    return 0;
169 		  len -= i;
170 		  addr += PAGE_SIZE;
171 		}
172 	    }
173 	  else
174 	    paddr += 16;
175 	}
176       break;
177 
178     default:
179     case FLUSH_SCOPE_PAGE:
180       len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
181       for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
182 	{
183 	  if (!(paddr = virt_to_phys_040(addr)))
184 	    continue;
185 	  switch (cache)
186 	    {
187 	    case FLUSH_CACHE_DATA:
188 	      __asm__ __volatile__ ("nop\n\t"
189 				    ".chip 68040\n\t"
190 				    "cpushp %%dc,(%0)\n\t"
191 				    ".chip 68k"
192 				    : : "a" (paddr));
193 	      break;
194 	    case FLUSH_CACHE_INSN:
195 	      __asm__ __volatile__ ("nop\n\t"
196 				    ".chip 68040\n\t"
197 				    "cpushp %%ic,(%0)\n\t"
198 				    ".chip 68k"
199 				    : : "a" (paddr));
200 	      break;
201 	    default:
202 	    case FLUSH_CACHE_BOTH:
203 	      __asm__ __volatile__ ("nop\n\t"
204 				    ".chip 68040\n\t"
205 				    "cpushp %%bc,(%0)\n\t"
206 				    ".chip 68k"
207 				    : : "a" (paddr));
208 	      break;
209 	    }
210 	}
211       break;
212     }
213   return 0;
214 }
215 
216 #define virt_to_phys_060(vaddr)				\
217 ({							\
218   unsigned long paddr;					\
219   __asm__ __volatile__ (".chip 68060\n\t"		\
220 			"plpar (%0)\n\t"		\
221 			".chip 68k"			\
222 			: "=a" (paddr)			\
223 			: "0" (vaddr));			\
224   (paddr); /* XXX */					\
225 })
226 
227 static inline int
228 cache_flush_060 (unsigned long addr, int scope, int cache, unsigned long len)
229 {
230   unsigned long paddr, i;
231 
232   /*
233    * 68060 manual says:
234    *  cpush %dc : flush DC, remains valid (with our %cacr setup)
235    *  cpush %ic : invalidate IC
236    *  cpush %bc : flush DC + invalidate IC
237    */
238   switch (scope)
239     {
240     case FLUSH_SCOPE_ALL:
241       switch (cache)
242 	{
243 	case FLUSH_CACHE_DATA:
244 	  __asm__ __volatile__ (".chip 68060\n\t"
245 				"cpusha %dc\n\t"
246 				".chip 68k");
247 	  break;
248 	case FLUSH_CACHE_INSN:
249 	  __asm__ __volatile__ (".chip 68060\n\t"
250 				"cpusha %ic\n\t"
251 				".chip 68k");
252 	  break;
253 	default:
254 	case FLUSH_CACHE_BOTH:
255 	  __asm__ __volatile__ (".chip 68060\n\t"
256 				"cpusha %bc\n\t"
257 				".chip 68k");
258 	  break;
259 	}
260       break;
261 
262     case FLUSH_SCOPE_LINE:
263       /* Find the physical address of the first mapped page in the
264 	 address range.  */
265       len += addr & 15;
266       addr &= -16;
267       if (!(paddr = virt_to_phys_060(addr))) {
268 	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
269 
270 	if (len <= tmp)
271 	  return 0;
272 	addr += tmp;
273 	len -= tmp;
274 	tmp = PAGE_SIZE;
275 	for (;;)
276 	  {
277 	    if ((paddr = virt_to_phys_060(addr)))
278 	      break;
279 	    if (len <= tmp)
280 	      return 0;
281 	    addr += tmp;
282 	    len -= tmp;
283 	  }
284       }
285       len = (len + 15) >> 4;
286       i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
287       while (len--)
288 	{
289 	  switch (cache)
290 	    {
291 	    case FLUSH_CACHE_DATA:
292 	      __asm__ __volatile__ (".chip 68060\n\t"
293 				    "cpushl %%dc,(%0)\n\t"
294 				    ".chip 68k"
295 				    : : "a" (paddr));
296 	      break;
297 	    case FLUSH_CACHE_INSN:
298 	      __asm__ __volatile__ (".chip 68060\n\t"
299 				    "cpushl %%ic,(%0)\n\t"
300 				    ".chip 68k"
301 				    : : "a" (paddr));
302 	      break;
303 	    default:
304 	    case FLUSH_CACHE_BOTH:
305 	      __asm__ __volatile__ (".chip 68060\n\t"
306 				    "cpushl %%bc,(%0)\n\t"
307 				    ".chip 68k"
308 				    : : "a" (paddr));
309 	      break;
310 	    }
311 	  if (!--i && len)
312 	    {
313 
314 	      /*
315 	       * We just want to jump to the first cache line
316 	       * in the next page.
317 	       */
318 	      addr += PAGE_SIZE;
319 	      addr &= PAGE_MASK;
320 
321 	      i = PAGE_SIZE / 16;
322 	      /* Recompute physical address when crossing a page
323 	         boundary. */
324 	      for (;;)
325 	        {
326 	          if ((paddr = virt_to_phys_060(addr)))
327 	            break;
328 	          if (len <= i)
329 	            return 0;
330 	          len -= i;
331 	          addr += PAGE_SIZE;
332 	        }
333 	    }
334 	  else
335 	    paddr += 16;
336 	}
337       break;
338 
339     default:
340     case FLUSH_SCOPE_PAGE:
341       len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
342       addr &= PAGE_MASK;	/* Workaround for bug in some
343 				   revisions of the 68060 */
344       for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
345 	{
346 	  if (!(paddr = virt_to_phys_060(addr)))
347 	    continue;
348 	  switch (cache)
349 	    {
350 	    case FLUSH_CACHE_DATA:
351 	      __asm__ __volatile__ (".chip 68060\n\t"
352 				    "cpushp %%dc,(%0)\n\t"
353 				    ".chip 68k"
354 				    : : "a" (paddr));
355 	      break;
356 	    case FLUSH_CACHE_INSN:
357 	      __asm__ __volatile__ (".chip 68060\n\t"
358 				    "cpushp %%ic,(%0)\n\t"
359 				    ".chip 68k"
360 				    : : "a" (paddr));
361 	      break;
362 	    default:
363 	    case FLUSH_CACHE_BOTH:
364 	      __asm__ __volatile__ (".chip 68060\n\t"
365 				    "cpushp %%bc,(%0)\n\t"
366 				    ".chip 68k"
367 				    : : "a" (paddr));
368 	      break;
369 	    }
370 	}
371       break;
372     }
373   return 0;
374 }
375 
376 /* sys_cacheflush -- flush (part of) the processor cache.  */
377 asmlinkage int
378 sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
379 {
380 	int ret = -EINVAL;
381 
382 	if (scope < FLUSH_SCOPE_LINE || scope > FLUSH_SCOPE_ALL ||
383 	    cache & ~FLUSH_CACHE_BOTH)
384 		goto out;
385 
386 	if (scope == FLUSH_SCOPE_ALL) {
387 		/* Only the superuser may explicitly flush the whole cache. */
388 		ret = -EPERM;
389 		if (!capable(CAP_SYS_ADMIN))
390 			goto out;
391 	} else {
392 		struct vm_area_struct *vma;
393 
394 		/* Check for overflow.  */
395 		if (addr + len < addr)
396 			goto out;
397 
398 		/*
399 		 * Verify that the specified address region actually belongs
400 		 * to this process.
401 		 */
402 		down_read(&current->mm->mmap_sem);
403 		vma = find_vma(current->mm, addr);
404 		if (!vma || addr < vma->vm_start || addr + len > vma->vm_end)
405 			goto out_unlock;
406 	}
407 
408 	if (CPU_IS_020_OR_030) {
409 		if (scope == FLUSH_SCOPE_LINE && len < 256) {
410 			unsigned long cacr;
411 			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
412 			if (cache & FLUSH_CACHE_INSN)
413 				cacr |= 4;
414 			if (cache & FLUSH_CACHE_DATA)
415 				cacr |= 0x400;
416 			len >>= 2;
417 			while (len--) {
418 				__asm__ __volatile__ ("movec %1, %%caar\n\t"
419 						      "movec %0, %%cacr"
420 						      : /* no outputs */
421 						      : "r" (cacr), "r" (addr));
422 				addr += 4;
423 			}
424 		} else {
425 			/* Flush the whole cache, even if page granularity requested. */
426 			unsigned long cacr;
427 			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
428 			if (cache & FLUSH_CACHE_INSN)
429 				cacr |= 8;
430 			if (cache & FLUSH_CACHE_DATA)
431 				cacr |= 0x800;
432 			__asm__ __volatile__ ("movec %0, %%cacr" : : "r" (cacr));
433 		}
434 		ret = 0;
435 		goto out_unlock;
436 	} else {
437 	    /*
438 	     * 040 or 060: don't blindly trust 'scope', someone could
439 	     * try to flush a few megs of memory.
440 	     */
441 
442 	    if (len>=3*PAGE_SIZE && scope<FLUSH_SCOPE_PAGE)
443 	        scope=FLUSH_SCOPE_PAGE;
444 	    if (len>=10*PAGE_SIZE && scope<FLUSH_SCOPE_ALL)
445 	        scope=FLUSH_SCOPE_ALL;
446 	    if (CPU_IS_040) {
447 		ret = cache_flush_040 (addr, scope, cache, len);
448 	    } else if (CPU_IS_060) {
449 		ret = cache_flush_060 (addr, scope, cache, len);
450 	    }
451 	}
452 out_unlock:
453 	up_read(&current->mm->mmap_sem);
454 out:
455 	return ret;
456 }
457 
458 /* This syscall gets its arguments in A0 (mem), D2 (oldval) and
459    D1 (newval).  */
460 asmlinkage int
461 sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
462 		      unsigned long __user * mem)
463 {
464 	/* This was borrowed from ARM's implementation.  */
465 	for (;;) {
466 		struct mm_struct *mm = current->mm;
467 		pgd_t *pgd;
468 		pmd_t *pmd;
469 		pte_t *pte;
470 		spinlock_t *ptl;
471 		unsigned long mem_value;
472 
473 		down_read(&mm->mmap_sem);
474 		pgd = pgd_offset(mm, (unsigned long)mem);
475 		if (!pgd_present(*pgd))
476 			goto bad_access;
477 		pmd = pmd_offset(pgd, (unsigned long)mem);
478 		if (!pmd_present(*pmd))
479 			goto bad_access;
480 		pte = pte_offset_map_lock(mm, pmd, (unsigned long)mem, &ptl);
481 		if (!pte_present(*pte) || !pte_dirty(*pte)
482 		    || !pte_write(*pte)) {
483 			pte_unmap_unlock(pte, ptl);
484 			goto bad_access;
485 		}
486 
487 		/*
488 		 * No need to check for EFAULT; we know that the page is
489 		 * present and writable.
490 		 */
491 		__get_user(mem_value, mem);
492 		if (mem_value == oldval)
493 			__put_user(newval, mem);
494 
495 		pte_unmap_unlock(pte, ptl);
496 		up_read(&mm->mmap_sem);
497 		return mem_value;
498 
499 	      bad_access:
500 		up_read(&mm->mmap_sem);
501 		/* This is not necessarily a bad access, we can get here if
502 		   a memory we're trying to write to should be copied-on-write.
503 		   Make the kernel do the necessary page stuff, then re-iterate.
504 		   Simulate a write access fault to do that.  */
505 		{
506 			/* The first argument of the function corresponds to
507 			   D1, which is the first field of struct pt_regs.  */
508 			struct pt_regs *fp = (struct pt_regs *)&newval;
509 
510 			/* '3' is an RMW flag.  */
511 			if (do_page_fault(fp, (unsigned long)mem, 3))
512 				/* If the do_page_fault() failed, we don't
513 				   have anything meaningful to return.
514 				   There should be a SIGSEGV pending for
515 				   the process.  */
516 				return 0xdeadbeef;
517 		}
518 	}
519 }
520 
521 #else
522 
523 /* sys_cacheflush -- flush (part of) the processor cache.  */
524 asmlinkage int
525 sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
526 {
527 	flush_cache_all();
528 	return 0;
529 }
530 
531 /* This syscall gets its arguments in A0 (mem), D2 (oldval) and
532    D1 (newval).  */
533 asmlinkage int
534 sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
535 		      unsigned long __user * mem)
536 {
537 	struct mm_struct *mm = current->mm;
538 	unsigned long mem_value;
539 
540 	down_read(&mm->mmap_sem);
541 
542 	mem_value = *mem;
543 	if (mem_value == oldval)
544 		*mem = newval;
545 
546 	up_read(&mm->mmap_sem);
547 	return mem_value;
548 }
549 
550 #endif /* CONFIG_MMU */
551 
552 asmlinkage int sys_getpagesize(void)
553 {
554 	return PAGE_SIZE;
555 }
556 
557 asmlinkage unsigned long sys_get_thread_area(void)
558 {
559 	return current_thread_info()->tp_value;
560 }
561 
562 asmlinkage int sys_set_thread_area(unsigned long tp)
563 {
564 	current_thread_info()->tp_value = tp;
565 	return 0;
566 }
567 
568 asmlinkage int sys_atomic_barrier(void)
569 {
570 	/* no code needed for uniprocs */
571 	return 0;
572 }
573