mirror of
https://github.com/torvalds/linux.git
synced 2024-11-29 07:31:29 +00:00
5b058973d3
When building mips tinyconfig with clang the following warning show up:
arch/mips/lib/uncached.c:45:6: warning: variable 'sp' is uninitialized when used here [-Wuninitialized]
if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
^~
arch/mips/lib/uncached.c:40:18: note: initialize the variable 'sp' to silence this warning
register long sp __asm__("$sp");
^
= 0
1 warning generated.
Rework to make an explicit inline move, instead of the non-standard use
of specifying registers for local variables. This is what's written
from the gcc-10 manual [1] about specifying registers for local
variables:
"6.47.5.2 Specifying Registers for Local Variables
.................................................
[...]
"The only supported use for this feature is to specify registers for
input and output operands when calling Extended 'asm' (*note Extended
Asm::). [...]".
[1] https://docs.w3cub.com/gcc~10/local-register-variables
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
/*
|
|
* 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 ret __asm__("$2");
|
|
long lfunc = (long)func, ufunc;
|
|
long usp;
|
|
long sp;
|
|
|
|
__asm__("move %0, $sp" : "=r" (sp));
|
|
|
|
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;
|
|
}
|