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

[Christophe Leroy]

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 <atraj...@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;

> +
> +     return -ENOENT;
> +}