uncached.c
2.05 KB
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/*
* 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 <asm/addrspace.h>
#include <asm/bug.h>
#include <asm/cacheflush.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 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;
}