[PATCH v2 09/13] powerpc/xmon: Dump prefixed instructions

[Jordan Niethe]

On Tue, Feb 11, 2020 at 5:39 PM Christophe Leroy
<christophe.leroy at c-s.fr> wrote:
>
>
>
> Le 11/02/2020 à 06:33, Jordan Niethe a écrit :
> > Currently when xmon is dumping instructions it reads a word at a time
> > and then prints that instruction (either as a hex number or by
> > disassembling it). For prefixed instructions it would be nice to show
> > its prefix and suffix as together. Use read_instr() so that if a prefix
> > is encountered its suffix is loaded too. Then print these in the form:
> >      prefix:suffix
> > Xmon uses the disassembly routines from GNU binutils. These currently do
> > not support prefixed instructions so we will not disassemble the
> > prefixed instructions yet.
> >
> > Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
> > ---
> > v2: Rename sufx to suffix
> > ---
> >   arch/powerpc/xmon/xmon.c | 50 +++++++++++++++++++++++++++++++---------
> >   1 file changed, 39 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> > index 0b085642bbe7..513901ee18b0 100644
> > --- a/arch/powerpc/xmon/xmon.c
> > +++ b/arch/powerpc/xmon/xmon.c
> > @@ -2903,6 +2903,21 @@ prdump(unsigned long adrs, long ndump)
> >       }
> >   }
> >
> > +static bool instrs_are_equal(unsigned long insta, unsigned long suffixa,
> > +                          unsigned long instb, unsigned long suffixb)
> > +{
> > +     if (insta != instb)
> > +             return false;
> > +
> > +     if (!IS_PREFIX(insta) && !IS_PREFIX(instb))
> > +             return true;
> > +
> > +     if (IS_PREFIX(insta) && IS_PREFIX(instb))
> > +             return suffixa == suffixb;
> > +
> > +     return false;
> > +}
> > +
> >   typedef int (*instruction_dump_func)(unsigned long inst, unsigned long addr);
> >
> >   static int
> > @@ -2911,12 +2926,11 @@ generic_inst_dump(unsigned long adr, long count, int praddr,
> >   {
> >       int nr, dotted;
> >       unsigned long first_adr;
> > -     unsigned int inst, last_inst = 0;
> > -     unsigned char val[4];
> > +     unsigned int inst, suffix, last_inst = 0, last_suffix = 0;
> >
> >       dotted = 0;
> > -     for (first_adr = adr; count > 0; --count, adr += 4) {
> > -             nr = mread(adr, val, 4);
> > +     for (first_adr = adr; count > 0; --count, adr += nr) {
> > +             nr = read_instr(adr, &inst, &suffix);
> >               if (nr == 0) {
> >                       if (praddr) {
> >                               const char *x = fault_chars[fault_type];
> > @@ -2924,8 +2938,9 @@ generic_inst_dump(unsigned long adr, long count, int praddr,
> >                       }
> >                       break;
> >               }
> > -             inst = GETWORD(val);
> > -             if (adr > first_adr && inst == last_inst) {
> > +             if (adr > first_adr && instrs_are_equal(inst, suffix,
> > +                                                     last_inst,
> > +                                                     last_suffix)) {
> >                       if (!dotted) {
> >                               printf(" ...\n");
> >                               dotted = 1;
> > @@ -2934,11 +2949,24 @@ generic_inst_dump(unsigned long adr, long count, int praddr,
> >               }
> >               dotted = 0;
> >               last_inst = inst;
> > -             if (praddr)
> > -                     printf(REG"  %.8x", adr, inst);
> > -             printf("\t");
> > -             dump_func(inst, adr);
> > -             printf("\n");
> > +             last_suffix = suffix;
> > +             if (IS_PREFIX(inst)) {
> > +                     if (praddr)
> > +                             printf(REG"  %.8x:%.8x", adr, inst, suffix);
> > +                     printf("\t");
> > +                     /*
> > +                      * Just use this until binutils ppc disassembly
> > +                      * prints prefixed instructions.
> > +                      */
> > +                     printf("%.8x:%.8x", inst, suffix);
> > +                     printf("\n");
> > +             } else {
> > +                     if (praddr)
> > +                             printf(REG"  %.8x", adr, inst);
> > +                     printf("\t");
> > +                     dump_func(inst, adr);
> > +                     printf("\n");
> > +             }
>
> What about:
>
>
>                 if (pr_addr) {
>                         printf(REG"  %.8x", adr, inst);
>                         if (IS_PREFIX(inst))
>                                 printf(":%.8x", suffix);
>                 }
>                 printf("\t");
>                 if (IS_PREFIX(inst))
>                         printf("%.8x:%.8x", inst, suffix);
>                 else
>                         dump_func(inst, adr);
>                 printf("\n");
>
Yeah that looks better.
> >       }
> >       return adr - first_adr;
> >   }
> >
>
> Christophe