text: /*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 2005 Thiemo Seufer
   * Copyright (C) 2005  MIPS Technologies, Inc.  All rights reserved.
   *	Author: Maciej W. Rozycki <macro@mips.com>
   */
  
  #include <linux/init.h>
  
  #include <asm/addrspace.h>
  #include <asm/bug.h>
  
  #ifndef CKSEG2
  #define CKSEG2 CKSSEG
  #endif
  #ifndef TO_PHYS_MASK
  #define TO_PHYS_MASK -1
  #endif
  
  /*
   * FUNC is executed in one of the uncached segments, depending on its
   * original address as follows:
   *
   * 1. If the original address is in CKSEG0 or CKSEG1, then the uncached
   *    segment used is CKSEG1.
   * 2. If the original address is in XKPHYS, then the uncached segment
   *    used is XKPHYS(2).
   * 3. Otherwise it's a bug.
   *
   * The same remapping is done with the stack pointer.  Stack handling
   * works because we don't handle stack arguments or more complex return
   * values, so we can avoid sharing the same stack area between a cached
   * and the uncached mode.
   */
  unsigned long __cpuinit run_uncached(void *func)
  {
  	register long sp __asm__("$sp");
  	register long ret __asm__("$2");
  	long lfunc = (long)func, ufunc;
  	long usp;
  
  	if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
  		usp = CKSEG1ADDR(sp);
  #ifdef CONFIG_64BIT
  	else if ((long long)sp >= (long long)PHYS_TO_XKPHYS(0, 0) &&
  		 (long long)sp < (long long)PHYS_TO_XKPHYS(8, 0))
  		usp = PHYS_TO_XKPHYS(K_CALG_UNCACHED,
  				     XKPHYS_TO_PHYS((long long)sp));
  #endif
  	else {
  		BUG();
  		usp = sp;
  	}
  	if (lfunc >= (long)CKSEG0 && lfunc < (long)CKSEG2)
  		ufunc = CKSEG1ADDR(lfunc);
  #ifdef CONFIG_64BIT
  	else if ((long long)lfunc >= (long long)PHYS_TO_XKPHYS(0, 0) &&
  		 (long long)lfunc < (long long)PHYS_TO_XKPHYS(8, 0))
  		ufunc = PHYS_TO_XKPHYS(K_CALG_UNCACHED,
  				       XKPHYS_TO_PHYS((long long)lfunc));
  #endif
  	else {
  		BUG();
  		ufunc = lfunc;
  	}
  
  	__asm__ __volatile__ (
  		"	move	$16, $sp\n"
  		"	move	$sp, %1\n"
  		"	jalr	%2\n"
  		"	move	$sp, $16"
  		: "=r" (ret)
  		: "r" (usp), "r" (ufunc)
  		: "$16", "$31");
  
  	return ret;
  }
  