Re: [PATCH v2] mips: lib: uncached: fix non-standard usage of variable 'sp'

From: Thomas Bogendoerfer
Date: Mon Dec 14 2020 - 10:28:26 EST


On Fri, Dec 11, 2020 at 11:24:37AM +0100, Anders Roxell wrote:
> 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@xxxxxxxxxx>
> ---
> arch/mips/lib/uncached.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)

applied to mips-next.

Thomas.

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