Re: [PATCH v2 2/3] hw/mips/gt64xxx: Remove dynamic field width from trace events

[Philippe Mathieu-Daudé]

On 11/14/19 10:24 PM, Philippe Mathieu-Daudé wrote:
> On 11/8/19 4:58 PM, Eric Blake wrote:
> > On 11/8/19 8:40 AM, Philippe Mathieu-Daudé wrote:
> > > Since not all trace backends support dynamic field width in
> > > format (dtrace via stap does not), replace by a static field
> > > width instead.
> > >
> > > Reported-by: Eric Blake <address@hidden>
> > > Buglink: https://bugs.launchpad.net/qemu/+bug/1844817
> > > Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> > > ---
> > > v2: Do not update qemu_log_mask()
> > > ---
> > >   hw/mips/gt64xxx_pci.c | 16 ++++++++--------
> > >   hw/mips/trace-events  |  4 ++--
> > >   2 files changed, 10 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/hw/mips/gt64xxx_pci.c b/hw/mips/gt64xxx_pci.c
> > > index 5cab9c1ee1..6743e7c929 100644
> > > --- a/hw/mips/gt64xxx_pci.c
> > > +++ b/hw/mips/gt64xxx_pci.c
> > > @@ -642,19 +642,19 @@ static void gt64120_writel(void *opaque, hwaddr 
> > > addr,
> > >           /* not really implemented */
> > >           s->regs[saddr] = ~(~(s->regs[saddr]) | ~(val & 0xfffffffe));
> > >           s->regs[saddr] |= !!(s->regs[saddr] & 0xfffffffe);
> > > -        trace_gt64120_write("INTRCAUSE", size << 1, val);
> > > +        trace_gt64120_write("INTRCAUSE", size << 3, val);
> >
> > Again, this isn't mentioned in the commit message.  Why are you 
> > changing parameter values?
> >
> >
> > > +++ b/hw/mips/trace-events
> > > @@ -1,4 +1,4 @@
> > >   # gt64xxx.c
> > > -gt64120_read(const char *regname, int width, uint64_t value) 
> > > "gt64120 read %s value:0x%0*" PRIx64
> > > -gt64120_write(const char *regname, int width, uint64_t value) 
> > > "gt64120 write %s value:0x%0*" PRIx64
> > > +gt64120_read(const char *regname, int width, uint64_t value) 
> > > "gt64120 read %s width:%d value:0x%08" PRIx64
> > > +gt64120_write(const char *regname, int width, uint64_t value) 
> > > "gt64120 write %s width:%d value:0x%08" PRIx64
> >
> > Huh, we were really broken - the old code (if passed to printf) would 
> > try to parse 4 parameters, even though it was only passed 3.  But it 
> > looks like you still need a v3.
>
> Oops. I am surprise the compiler doesn't emit a warning here...

I'm sorry I can't see the 4th parameter.

Before: "gt64120 read %s value:0x%0*" PRIx64

#1 's' for 'const char *regname'
#2 '0*' for 'int width'
#3 'x' for 'uint64_t value'

After: "gt64120 read %s width:%d value:0x%08" PRIx64

#1 's' for 'const char *regname'
#2 'd' for 'int width'
#3 '08x' for 'uint64_t value'

Am I missing something?