sys_m68k.c

// SPDX-License-Identifier: GPL-2.0
/*
 * linux/arch/m68k/kernel/sys_m68k.c
 *
 * This file contains various random system calls that
 * have a non-standard calling sequence on the Linux/m68k
 * platform.
 */

#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/syscalls.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/ipc.h>

#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/cachectl.h>
#include <asm/traps.h>
#include <asm/page.h>
#include <asm/syscalls.h>
#include <asm/unistd.h>
#include <asm/cacheflush.h>

#ifdef CONFIG_MMU

#include <asm/tlb.h>

#include "../mm/fault.h"

asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
	unsigned long prot, unsigned long flags,
	unsigned long fd, unsigned long pgoff)
{
	/*
	 * This is wrong for sun3 - there PAGE_SIZE is 8Kb,
	 * so we need to shift the argument down by 1; m68k mmap64(3)
	 * (in libc) expects the last argument of mmap2 in 4Kb units.
	 */
	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
}

/* Convert virtual (user) address VADDR to physical address PADDR */
#define virt_to_phys_040(vaddr)						\
({									\
  unsigned long _mmusr, _paddr;						\
									\
  __asm__ __volatile__ (".chip 68040\n\t"				\
			"ptestr (%1)\n\t"				\
			"movec %%mmusr,%0\n\t"				\
			".chip 68k"					\
			: "=r" (_mmusr)					\
			: "a" (vaddr));					\
  _paddr = (_mmusr & MMU_R_040) ? (_mmusr & PAGE_MASK) : 0;		\
  _paddr;								\
})

static inline int
cache_flush_040 (unsigned long addr, int scope, int cache, unsigned long len)
{
  unsigned long paddr, i;

  switch (scope)
    {
    case FLUSH_SCOPE_ALL:
      switch (cache)
	{
	case FLUSH_CACHE_DATA:
	  /* This nop is needed for some broken versions of the 68040.  */
	  __asm__ __volatile__ ("nop\n\t"
				".chip 68040\n\t"
				"cpusha %dc\n\t"
				".chip 68k");
	  break;
	case FLUSH_CACHE_INSN:
	  __asm__ __volatile__ ("nop\n\t"
				".chip 68040\n\t"
				"cpusha %ic\n\t"
				".chip 68k");
	  break;
	default:
	case FLUSH_CACHE_BOTH:
	  __asm__ __volatile__ ("nop\n\t"
				".chip 68040\n\t"
				"cpusha %bc\n\t"
				".chip 68k");
	  break;
	}
      break;

    case FLUSH_SCOPE_LINE:
      /* Find the physical address of the first mapped page in the
	 address range.  */
      if ((paddr = virt_to_phys_040(addr))) {
        paddr += addr & ~(PAGE_MASK | 15);
        len = (len + (addr & 15) + 15) >> 4;
      } else {
	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);

	if (len <= tmp)
	  return 0;
	addr += tmp;
	len -= tmp;
	tmp = PAGE_SIZE;
	for (;;)
	  {
	    if ((paddr = virt_to_phys_040(addr)))
	      break;
	    if (len <= tmp)
	      return 0;
	    addr += tmp;
	    len -= tmp;
	  }
	len = (len + 15) >> 4;
      }
      i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
      while (len--)
	{
	  switch (cache)
	    {
	    case FLUSH_CACHE_DATA:
	      __asm__ __volatile__ ("nop\n\t"
				    ".chip 68040\n\t"
				    "cpushl %%dc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    case FLUSH_CACHE_INSN:
	      __asm__ __volatile__ ("nop\n\t"
				    ".chip 68040\n\t"
				    "cpushl %%ic,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    default:
	    case FLUSH_CACHE_BOTH:
	      __asm__ __volatile__ ("nop\n\t"
				    ".chip 68040\n\t"
				    "cpushl %%bc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    }
	  if (!--i && len)
	    {
	      /*
	       * No need to page align here since it is done by
	       * virt_to_phys_040().
	       */
	      addr += PAGE_SIZE;
	      i = PAGE_SIZE / 16;
	      /* Recompute physical address when crossing a page
	         boundary. */
	      for (;;)
		{
		  if ((paddr = virt_to_phys_040(addr)))
		    break;
		  if (len <= i)
		    return 0;
		  len -= i;
		  addr += PAGE_SIZE;
		}
	    }
	  else
	    paddr += 16;
	}
      break;

    default:
    case FLUSH_SCOPE_PAGE:
      len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
      for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
	{
	  if (!(paddr = virt_to_phys_040(addr)))
	    continue;
	  switch (cache)
	    {
	    case FLUSH_CACHE_DATA:
	      __asm__ __volatile__ ("nop\n\t"
				    ".chip 68040\n\t"
				    "cpushp %%dc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    case FLUSH_CACHE_INSN:
	      __asm__ __volatile__ ("nop\n\t"
				    ".chip 68040\n\t"
				    "cpushp %%ic,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    default:
	    case FLUSH_CACHE_BOTH:
	      __asm__ __volatile__ ("nop\n\t"
				    ".chip 68040\n\t"
				    "cpushp %%bc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    }
	}
      break;
    }
  return 0;
}

#define virt_to_phys_060(vaddr)				\
({							\
  unsigned long paddr;					\
  __asm__ __volatile__ (".chip 68060\n\t"		\
			"plpar (%0)\n\t"		\
			".chip 68k"			\
			: "=a" (paddr)			\
			: "0" (vaddr));			\
  (paddr); /* XXX */					\
})

static inline int
cache_flush_060 (unsigned long addr, int scope, int cache, unsigned long len)
{
  unsigned long paddr, i;

  /*
   * 68060 manual says:
   *  cpush %dc : flush DC, remains valid (with our %cacr setup)
   *  cpush %ic : invalidate IC
   *  cpush %bc : flush DC + invalidate IC
   */
  switch (scope)
    {
    case FLUSH_SCOPE_ALL:
      switch (cache)
	{
	case FLUSH_CACHE_DATA:
	  __asm__ __volatile__ (".chip 68060\n\t"
				"cpusha %dc\n\t"
				".chip 68k");
	  break;
	case FLUSH_CACHE_INSN:
	  __asm__ __volatile__ (".chip 68060\n\t"
				"cpusha %ic\n\t"
				".chip 68k");
	  break;
	default:
	case FLUSH_CACHE_BOTH:
	  __asm__ __volatile__ (".chip 68060\n\t"
				"cpusha %bc\n\t"
				".chip 68k");
	  break;
	}
      break;

    case FLUSH_SCOPE_LINE:
      /* Find the physical address of the first mapped page in the
	 address range.  */
      len += addr & 15;
      addr &= -16;
      if (!(paddr = virt_to_phys_060(addr))) {
	unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);

	if (len <= tmp)
	  return 0;
	addr += tmp;
	len -= tmp;
	tmp = PAGE_SIZE;
	for (;;)
	  {
	    if ((paddr = virt_to_phys_060(addr)))
	      break;
	    if (len <= tmp)
	      return 0;
	    addr += tmp;
	    len -= tmp;
	  }
      }
      len = (len + 15) >> 4;
      i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
      while (len--)
	{
	  switch (cache)
	    {
	    case FLUSH_CACHE_DATA:
	      __asm__ __volatile__ (".chip 68060\n\t"
				    "cpushl %%dc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    case FLUSH_CACHE_INSN:
	      __asm__ __volatile__ (".chip 68060\n\t"
				    "cpushl %%ic,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    default:
	    case FLUSH_CACHE_BOTH:
	      __asm__ __volatile__ (".chip 68060\n\t"
				    "cpushl %%bc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    }
	  if (!--i && len)
	    {

	      /*
	       * We just want to jump to the first cache line
	       * in the next page.
	       */
	      addr += PAGE_SIZE;
	      addr &= PAGE_MASK;

	      i = PAGE_SIZE / 16;
	      /* Recompute physical address when crossing a page
	         boundary. */
	      for (;;)
	        {
	          if ((paddr = virt_to_phys_060(addr)))
	            break;
	          if (len <= i)
	            return 0;
	          len -= i;
	          addr += PAGE_SIZE;
	        }
	    }
	  else
	    paddr += 16;
	}
      break;

    default:
    case FLUSH_SCOPE_PAGE:
      len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
      addr &= PAGE_MASK;	/* Workaround for bug in some
				   revisions of the 68060 */
      for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
	{
	  if (!(paddr = virt_to_phys_060(addr)))
	    continue;
	  switch (cache)
	    {
	    case FLUSH_CACHE_DATA:
	      __asm__ __volatile__ (".chip 68060\n\t"
				    "cpushp %%dc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    case FLUSH_CACHE_INSN:
	      __asm__ __volatile__ (".chip 68060\n\t"
				    "cpushp %%ic,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    default:
	    case FLUSH_CACHE_BOTH:
	      __asm__ __volatile__ (".chip 68060\n\t"
				    "cpushp %%bc,(%0)\n\t"
				    ".chip 68k"
				    : : "a" (paddr));
	      break;
	    }
	}
      break;
    }
  return 0;
}

/* sys_cacheflush -- flush (part of) the processor cache.  */
asmlinkage int
sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
{
	int ret = -EINVAL;

	if (scope < FLUSH_SCOPE_LINE || scope > FLUSH_SCOPE_ALL ||
	    cache & ~FLUSH_CACHE_BOTH)
		goto out;

	if (scope == FLUSH_SCOPE_ALL) {
		/* Only the superuser may explicitly flush the whole cache. */
		ret = -EPERM;
		if (!capable(CAP_SYS_ADMIN))
			goto out;

		mmap_read_lock(current->mm);
	} else {
		struct vm_area_struct *vma;

		/* Check for overflow.  */
		if (addr + len < addr)
			goto out;

		/*
		 * Verify that the specified address region actually belongs
		 * to this process.
		 */
		mmap_read_lock(current->mm);
		vma = vma_lookup(current->mm, addr);
		if (!vma || addr + len > vma->vm_end)
			goto out_unlock;
	}

	if (CPU_IS_020_OR_030) {
		if (scope == FLUSH_SCOPE_LINE && len < 256) {
			unsigned long cacr;
			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
			if (cache & FLUSH_CACHE_INSN)
				cacr |= 4;
			if (cache & FLUSH_CACHE_DATA)
				cacr |= 0x400;
			len >>= 2;
			while (len--) {
				__asm__ __volatile__ ("movec %1, %%caar\n\t"
						      "movec %0, %%cacr"
						      : /* no outputs */
						      : "r" (cacr), "r" (addr));
				addr += 4;
			}
		} else {
			/* Flush the whole cache, even if page granularity requested. */
			unsigned long cacr;
			__asm__ ("movec %%cacr, %0" : "=r" (cacr));
			if (cache & FLUSH_CACHE_INSN)
				cacr |= 8;
			if (cache & FLUSH_CACHE_DATA)
				cacr |= 0x800;
			__asm__ __volatile__ ("movec %0, %%cacr" : : "r" (cacr));
		}
		ret = 0;
		goto out_unlock;
	} else {
	    /*
	     * 040 or 060: don't blindly trust 'scope', someone could
	     * try to flush a few megs of memory.
	     */

	    if (len>=3*PAGE_SIZE && scope<FLUSH_SCOPE_PAGE)
	        scope=FLUSH_SCOPE_PAGE;
	    if (len>=10*PAGE_SIZE && scope<FLUSH_SCOPE_ALL)
	        scope=FLUSH_SCOPE_ALL;
	    if (CPU_IS_040) {
		ret = cache_flush_040 (addr, scope, cache, len);
	    } else if (CPU_IS_060) {
		ret = cache_flush_060 (addr, scope, cache, len);
	    }
	}
out_unlock:
	mmap_read_unlock(current->mm);
out:
	return ret;
}

/* This syscall gets its arguments in A0 (mem), D2 (oldval) and
   D1 (newval).  */
asmlinkage int
sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
		      unsigned long __user * mem)
{
	/* This was borrowed from ARM's implementation.  */
	for (;;) {
		struct mm_struct *mm = current->mm;
		pgd_t *pgd;
		p4d_t *p4d;
		pud_t *pud;
		pmd_t *pmd;
		pte_t *pte;
		spinlock_t *ptl;
		unsigned long mem_value;

		mmap_read_lock(mm);
		pgd = pgd_offset(mm, (unsigned long)mem);
		if (!pgd_present(*pgd))
			goto bad_access;
		p4d = p4d_offset(pgd, (unsigned long)mem);
		if (!p4d_present(*p4d))
			goto bad_access;
		pud = pud_offset(p4d, (unsigned long)mem);
		if (!pud_present(*pud))
			goto bad_access;
		pmd = pmd_offset(pud, (unsigned long)mem);
		if (!pmd_present(*pmd))
			goto bad_access;
		pte = pte_offset_map_lock(mm, pmd, (unsigned long)mem, &ptl);
		if (!pte)
			goto bad_access;
		if (!pte_present(*pte) || !pte_dirty(*pte)
		    || !pte_write(*pte)) {
			pte_unmap_unlock(pte, ptl);
			goto bad_access;
		}

		/*
		 * No need to check for EFAULT; we know that the page is
		 * present and writable.
		 */
		__get_user(mem_value, mem);
		if (mem_value == oldval)
			__put_user(newval, mem);

		pte_unmap_unlock(pte, ptl);
		mmap_read_unlock(mm);
		return mem_value;

	      bad_access:
		mmap_read_unlock(mm);
		/* This is not necessarily a bad access, we can get here if
		   a memory we're trying to write to should be copied-on-write.
		   Make the kernel do the necessary page stuff, then re-iterate.
		   Simulate a write access fault to do that.  */
		{
			/* The first argument of the function corresponds to
			   D1, which is the first field of struct pt_regs.  */
			struct pt_regs *fp = (struct pt_regs *)&newval;

			/* '3' is an RMW flag.  */
			if (do_page_fault(fp, (unsigned long)mem, 3))
				/* If the do_page_fault() failed, we don't
				   have anything meaningful to return.
				   There should be a SIGSEGV pending for
				   the process.  */
				return 0xdeadbeef;
		}
	}
}

#else

/* sys_cacheflush -- flush (part of) the processor cache.  */
asmlinkage int
sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
{
	flush_cache_all();
	return 0;
}

/* This syscall gets its arguments in A0 (mem), D2 (oldval) and
   D1 (newval).  */
asmlinkage int
sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
		      unsigned long __user * mem)
{
	struct mm_struct *mm = current->mm;
	unsigned long mem_value;

	mmap_read_lock(mm);

	mem_value = *mem;
	if (mem_value == oldval)
		*mem = newval;

	mmap_read_unlock(mm);
	return mem_value;
}

#endif /* CONFIG_MMU */

asmlinkage int sys_getpagesize(void)
{
	return PAGE_SIZE;
}

asmlinkage unsigned long sys_get_thread_area(void)
{
	return current_thread_info()->tp_value;
}

asmlinkage int sys_set_thread_area(unsigned long tp)
{
	current_thread_info()->tp_value = tp;
	return 0;
}

asmlinkage int sys_atomic_barrier(void)
{
	/* no code needed for uniprocs */
	return 0;
}