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SubjectRe: [PATCH] mips: lib: uncached: fix uninitialized variable 'sp'
On Mon, 30 Nov 2020 at 21:22, Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> On Fri, Nov 27, 2020 at 12:39 AM Anders Roxell <anders.roxell@linaro.org> wrote:
> >
> > When building mips tinyconfig with clang the following warning show up:
> >
> > /tmp/arch/mips/lib/uncached.c:40:18: note: initialize the variable 'sp' to silence this warning
> > register long sp __asm__("$sp");
> > ^
> > = 0
>
> Hi Anders

Hi Nick,

>, thank you for sending the patch. Do you have the full text
> of the warning; it looks like only the note was included?

oops, looks like I missed this:

/srv/src/kernel/next/arch/mips/lib/uncached.c:45:6: warning: variable
'sp' is uninitialized when used here [-Wuninitialized]
if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
^~
/srv/src/kernel/next/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.

Cheers,
Anders

>
> >
> > Rework to make an explicit inline move.
> >
> > Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> > ---
> > arch/mips/lib/uncached.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c
> > index 09d5deea747f..21a4b94a0558 100644
> > --- a/arch/mips/lib/uncached.c
> > +++ b/arch/mips/lib/uncached.c
> > @@ -37,10 +37,11 @@
> > */
> > 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);
> > --
> > 2.29.2
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers

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