Re: [Qemu-devel] [PATCH v1 1/1] mips: properly compute hflags and fcr0 on cpu reset

["Andreas Färber" <afaerber@suse.de>]

Am 02.03.2012 22:03, schrieb Meador Inge:
> Currently 'cpu_reset' doesn't fully compute all of the needed
> HFLAGs and fails to setup fcr0 after clearing the CPU state.
> This can cause instruction exceptions.  For example, using
> 'madd.d' on machines that should support it is kindly greeted
> with:
> 
> qemu: uncaught target signal 4 (Illegal instruction) - core dumped
> Illegal instruction (core dumped)
> 
> because fcr0 is bogus and MIPS_HFLAG_COP1X is not correcly set in hflags.
> 
> This is fixed by modifying 'cpu_reset' to use 'compute_hflags' and
> initializing 'fcr0' from the current CPU model.

fcr0 issue has also been

Reported-by: Khansa Butt <khansa@kics.edu.pk>

e.g., http://patchwork.ozlabs.org/patch/133974/

Your use of compute_hflags() looks more future-proof.

> 
> Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com>
> Signed-off-by: Nathan Froyd <froydnj@codesourcery.com>
> Signed-off-by: Meador Inge <meadori@codesourcery.com>
> ---
>  target-mips/cpu.h       |   49 +++++++++++++++++++++++++++++++++++++++++++++++
>  target-mips/op_helper.c |   49 -----------------------------------------------
>  target-mips/translate.c |   17 +++------------
>  3 files changed, 53 insertions(+), 62 deletions(-)
> 
> diff --git a/target-mips/cpu.h b/target-mips/cpu.h
> index 71cb4e8..fc65348 100644
> --- a/target-mips/cpu.h
> +++ b/target-mips/cpu.h
> @@ -737,4 +737,53 @@ static inline void cpu_pc_from_tb(CPUState *env, TranslationBlock *tb)
>      env->hflags |= tb->flags & MIPS_HFLAG_BMASK;
>  }
>  
> +static inline void compute_hflags(CPUState *env)
> +{

Moving helper functions like these to cpu.h has proven troublesome for
QOM'ification (when they need access to MIPSCPU[Class] in addition to
CPUMIPSState) but it'll do for now.

Reviewed-by: Andreas Färber <afaerber@suse.de>

Andreas

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