| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.10 030/152] mips: lib: uncached: fix non-standard usage of variable sp | Date | Mon, 18 Jan 2021 12:33:25 +0100 |
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From: Anders Roxell <anders.roxell@linaro.org>
commit 5b058973d3205578aa6c9a71392e072a11ca44ef upstream.
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__("$sp"); ^ = 0 1 warning generated.
Rework to make an explicit inline move, instead of the non-standard use of specifying registers for local variables. This is what's written from the gcc-10 manual [1] about specifying registers for local variables:
"6.47.5.2 Specifying Registers for Local Variables ................................................. [...]
"The only supported use for this feature is to specify registers for input and output operands when calling Extended 'asm' (*note Extended Asm::). [...]".
[1] https://docs.w3cub.com/gcc~10/local-register-variables Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/mips/lib/uncached.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/mips/lib/uncached.c +++ b/arch/mips/lib/uncached.c @@ -37,10 +37,12 @@ */ unsigned long run_uncached(void *func) { - register long sp __asm__("$sp"); 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);
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