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

[Richard Henderson <richard.henderson@linaro.org>]

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.
> 
> 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~