Re: [PATCH 3/3] tools/perf/arch/powerc: Add get_arch_regnum for powerpc

[Athira Rajeev <atrajeev@linux.vnet.ibm.com>]

> On 09-Mar-2024, at 3:24 PM, Christophe Leroy <christophe.leroy@csgroup.eu> wrote:
> 
> 
> 
> Le 09/03/2024 à 08:25, Athira Rajeev a écrit :
>> The function get_dwarf_regnum() returns a DWARF register number
>> from a register name string. This calls arch specific function
>> get_arch_regnum to return register number for corresponding arch.
>> Add mappings for register name to register number in powerpc code:
>> arch/powerpc/util/dwarf-regs.c
>> 
>> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
>> ---
>>  tools/perf/arch/powerpc/util/dwarf-regs.c | 29 +++++++++++++++++++++++
>>  1 file changed, 29 insertions(+)
>> 
>> diff --git a/tools/perf/arch/powerpc/util/dwarf-regs.c b/tools/perf/arch/powerpc/util/dwarf-regs.c
>> index 0c4f4caf53ac..d955e3e577ea 100644
>> --- a/tools/perf/arch/powerpc/util/dwarf-regs.c
>> +++ b/tools/perf/arch/powerpc/util/dwarf-regs.c
>> @@ -98,3 +98,32 @@ int regs_query_register_offset(const char *name)
>>   return roff->ptregs_offset;
>>   return -EINVAL;
>>  }
>> +
>> +struct dwarf_regs_idx {
>> + const char *name;
>> + int idx;
>> +};
>> +
>> +static const struct dwarf_regs_idx powerpc_regidx_table[] = {
>> + { "r0", 0 }, { "r1", 1 }, { "r2", 2 }, { "r3", 3 }, { "r4", 4 },
>> + { "r5", 5 }, { "r6", 6 }, { "r7", 7 }, { "r8", 8 }, { "r9", 9 },
>> + { "r10", 10 }, { "r11", 11 }, { "r12", 12 }, { "r13", 13 }, { "r14", 14 },
>> + { "r15", 15 }, { "r16", 16 }, { "r17", 17 }, { "r18", 18 }, { "r19", 19 },
>> + { "r20", 20 }, { "r21", 21 }, { "r22", 22 }, { "r23", 23 }, { "r24", 24 },
>> + { "r25", 25 }, { "r26", 26 }, { "r27", 27 }, { "r27", 27 }, { "r28", 28 },
>> + { "r29", 29 }, { "r30", 30 }, { "r31", 31 },
>> +};
>> +
>> +int get_arch_regnum(const char *name)
>> +{
>> + unsigned int i;
>> +
>> + if (*name != 'r')
>> + return -EINVAL;
>> +
>> + for (i = 0; i < ARRAY_SIZE(powerpc_regidx_table); i++)
>> + if (!strcmp(powerpc_regidx_table[i].name, name))
>> + return powerpc_regidx_table[i].idx;
> 
> Can you do more simple ?
> 
> Something like:
> 
> int n;
> 
> if (*name != 'r')
> return -EINVAL;
> n = atoi(name + 1);
> return n >= 0 && n < 32 ? n : -ENOENT;

Hi Christophe,

Thanks for reviewing patch and for the suggestions.

Sure, I will check this approach and address in V2

Thanks
Athira
> 
>> +
>> + return -ENOENT;
>> +}