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__("$sp"); ^ = 0 1 warning generated.
Rework to make an explicit inline move, instead of the non-standard use of specifying registers for local variables. This is what's written from the gcc-10 manual [1] about specifying registers for local variables:
"6.47.5.2 Specifying Registers for Local Variables ................................................. [...]
"The only supported use for this feature is to specify registers for input and output operands when calling Extended 'asm' (*note Extended Asm::). [...]".
Cc: stable@vger.kernel.org # v5.4+ [1] https://docs.w3cub.com/gcc~10/local-register-variables Signed-off-by: Anders Roxell anders.roxell@linaro.org Reported-by: Nathan Chancellor natechancellor@gmail.com Reported-by: Naresh Kamboju naresh.kamboju@linaro.org Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de --- arch/mips/lib/uncached.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c index 09d5deea747f..f80a67c092b6 100644 --- a/arch/mips/lib/uncached.c +++ b/arch/mips/lib/uncached.c @@ -37,10 +37,12 @@ */ unsigned long run_uncached(void *func) { - register long sp __asm__("$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);