Re: oprofile callgraph support missing for common cpus

[Maynard Johnson <maynardj@us.ibm.com>]

On 11/17/2011 2:38 AM, Joakim Tjernlund wrote:
>
> arch/powerpc/oprofile/common.c has this init code:
>
> int __init oprofile_arch_init(struct oprofile_operations *ops)
> {
> 		 if (!cur_cpu_spec->oprofile_cpu_type)
> 		 		 return -ENODEV;
>
> 		 if (firmware_has_feature(FW_FEATURE_ISERIES))
> 		 		 return -ENODEV;
>
> 		 switch (cur_cpu_spec->oprofile_type) {
> #ifdef CONFIG_PPC_BOOK3S_64
> #ifdef CONFIG_OPROFILE_CELL
> 		 		 case PPC_OPROFILE_CELL:
> 		 		 		 if (firmware_has_feature(FW_FEATURE_LPAR))
> 		 		 		 		 return -ENODEV;
> 		 		 		 model =&op_model_cell;
> 		 		 		 ops->sync_start = model->sync_start;
> 		 		 		 ops->sync_stop = model->sync_stop;
> 		 		 		 break;
> #endif
> 		 		 case PPC_OPROFILE_RS64:
> 		 		 		 model =&op_model_rs64;
> 		 		 		 break;
> 		 		 case PPC_OPROFILE_POWER4:
> 		 		 		 model =&op_model_power4;
> 		 		 		 break;
> 		 		 case PPC_OPROFILE_PA6T:
> 		 		 		 model =&op_model_pa6t;
> 		 		 		 break;
> #endif
> #ifdef CONFIG_6xx
> 		 		 case PPC_OPROFILE_G4:
> 		 		 		 model =&op_model_7450;
> 		 		 		 break;
> #endif
> #if defined(CONFIG_FSL_EMB_PERFMON)
> 		 		 case PPC_OPROFILE_FSL_EMB:
> 		 		 		 model =&op_model_fsl_emb;
> 		 		 		 break;
> #endif
> 		 		 default:
> 		 		 		 return -ENODEV;
> 		 }
>
> 		 model->num_counters = cur_cpu_spec->num_pmcs;
>
> 		 ops->cpu_type = cur_cpu_spec->oprofile_cpu_type;
> 		 ops->create_files = op_powerpc_create_files;
> 		 ops->setup = op_powerpc_setup;
> 		 ops->shutdown = op_powerpc_shutdown;
> 		 ops->start = op_powerpc_start;
> 		 ops->stop = op_powerpc_stop;
> 		 ops->backtrace = op_powerpc_backtrace;
> }
>
> Notice the first
> 		 if (!cur_cpu_spec->oprofile_cpu_type)
> 		 		 return -ENODEV;
>
> 		 if (firmware_has_feature(FW_FEATURE_ISERIES))
> 		 		 return -ENODEV;
> For my e300c2 cpu both if's are false and I don't get support for callgraph/backtrace
> support. Moving the ops->backtrace = op_powerpc_backtrace; to the top
> enables backtrace for me.
What kernel version are you using?  Actually, looking at a 3.0.3 tree I happen 
to have available, I see oprofile h/w event support (in 
arch/powerpc/kernel/cputable.c) for e300c3 and e300c4, but not the other e300 
flavors.  I've added Andy Flemming from Freescale to cc.  Maybe he knows why 
e300c2 isn't supported.

-Maynard

>
> This function needs fixing so its not all or nothing but I cannot make out
> what is what so please, could someone look at this?
>
> I am somewhat behind mainline so I will just use my hack for now.
>
>   Jocke
>
>
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