Re: [PATCH] target/mips: Fix ll/sc after 7dd547e5ab6b31e7a0cfc182d3ad131dd55a948f

["Philippe Mathieu-Daudé" <philippe@mathieu-daude.net>]

On Mon, Feb 3, 2020 at 8:52 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
> On 2/2/20 3:34 PM, James Clarke wrote:
> > From: Alex Richardson <Alexander.Richardson@cl.cam.ac.uk>
> >
> > After 7dd547e5ab6b31e7a0cfc182d3ad131dd55a948f the env->llval value is
> > loaded as an unsigned value (instead of sign-extended as before).
> > Therefore, the CMPXCHG in gen_st_cond() in translate.c fails if the sign
> > bit is set in the loaded value.
> > Fix this by sign-extending the llval value for the 32-bit case.

Thanks!

This fix the problem I spent my Saturday debugging:
https://lists.gnu.org/archive/html/qemu-devel/2020-02/msg00071.html
Too bad we crossed by few hours, you'd have saved my Saturday.

Thomas, I think this also fixes the problem you reported here:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg676025.html

Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> >
> > I discovered this issue because FreeBSD MIPS64 was looping forever in an
> > atomic helper function when trying to start /sbin/init.
> >
> > Signed-off-by: Alex Richardson <Alexander.Richardson@cl.cam.ac.uk>
> > Fixes: 7dd547e5ab6b ("target/mips: Use cpu_*_mmuidx_ra instead of MMU_MODE*_SUFFIX")
> > Buglink: https://bugs.launchpad.net/qemu/+bug/1861605
> > Cc: Aurelien Jarno <aurelien@aurel32.net>
> > Cc: Aleksandar Markovic <amarkovic@wavecomp.com>
> > Cc: Aleksandar Rikalo <aleksandar.rikalo@rt-rk.com>
> > Cc: Richard Henderson <richard.henderson@linaro.org>
> > Signed-off-by: James Clarke <jrtc27@jrtc27.com>
> > ---
> >  target/mips/op_helper.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
>
> My fault.  Sorry about that.
>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>
>
> r~
>