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

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

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 <eblake@redhat.com>
>> Buglink: https://bugs.launchpad.net/qemu/+bug/1844817
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>> 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...