Re: [RFC PATCH v2 03/15] perf bpf: Save pt_regs info from debuginfo

[He Kuang <hekuang@huawei.com>]

On 2015/5/24 21:31, Masami Hiramatsu wrote:
> On 2015/05/24 17:27, He Kuang wrote:
>> Save reg number in function convert_variable_location() instead of the
>> register string name, so we can fetch the target register from bpf
>> context register later.
> 
> This is not needed because you can also get reg number from reg string
> afterwards.
> 
> Thank you,

Ok, thanks
> 
>>
>> Signed-off-by: He Kuang <hekuang@huawei.com>
>> ---
>>   tools/perf/util/include/dwarf-regs.h | 13 +++++++++++++
>>   tools/perf/util/probe-event.h        |  1 +
>>   tools/perf/util/probe-finder.c       | 11 +++++++++++
>>   3 files changed, 25 insertions(+)
>>
>> diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
>> index 8f14965..566ff6d 100644
>> --- a/tools/perf/util/include/dwarf-regs.h
>> +++ b/tools/perf/util/include/dwarf-regs.h
>> @@ -2,7 +2,20 @@
>>   #define _PERF_DWARF_REGS_H_
>>   
>>   #ifdef HAVE_DWARF_SUPPORT
>> +struct arch_regs_info {
>> +	const char      *name;  /* Architecture dependent register string */
>> +	int             offset; /* Reg offset in struct pt_regs */
>> +	int             size;   /* Reg size */
>> +};
>> +
>> +#define ARCH_REGS_INFO(r, pt_reg_name)					\
>> +	{.name	= r,							\
>> +	.offset = offsetof(struct pt_regs, pt_reg_name),		\
>> +	.size   = sizeof(((struct pt_regs *)0)->pt_reg_name)}		\
>> +
>>   const char *get_arch_regstr(unsigned int n);
>> +int get_arch_reg_offset(unsigned int n);
>> +int get_arch_reg_size(unsigned int n);
>>   #endif
>>   
>>   #endif
>> diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
>> index d6b7834..6c19395 100644
>> --- a/tools/perf/util/probe-event.h
>> +++ b/tools/perf/util/probe-event.h
>> @@ -29,6 +29,7 @@ struct probe_trace_arg {
>>   	char				*value;	/* Base value */
>>   	char				*type;	/* Type name */
>>   	struct probe_trace_arg_ref	*ref;	/* Referencing offset */
>> +	unsigned int                    regn;   /* Regn from dwarf */
>>   };
>>   
>>   /* kprobe-tracer and uprobe-tracer tracing event (point + arg) */
>> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
>> index ee27b74..681af00 100644
>> --- a/tools/perf/util/probe-finder.c
>> +++ b/tools/perf/util/probe-finder.c
>> @@ -159,6 +159,16 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
>>   	return ref;
>>   }
>>   
>> +int __attribute__ ((weak))
>> +get_arch_reg_offset(unsigned int n __maybe_unused) {
>> +	return -1;
>> +}
>> +
>> +int __attribute__ ((weak))
>> +get_arch_reg_size(unsigned int n __maybe_unused) {
>> +	return -1;
>> +}
>> +
>>   /*
>>    * Convert a location into trace_arg.
>>    * If tvar == NULL, this just checks variable can be converted.
>> @@ -260,6 +270,7 @@ static_var:
>>   		return -ERANGE;
>>   	}
>>   
>> +	tvar->regn = regn;
>>   	tvar->value = strdup(regs);
>>   	if (tvar->value == NULL)
>>   		return -ENOMEM;
>>
> 
>