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