[PATCH] ARM: perf: fix link error when CONFIG_HW_PERF_EVENTS is not selected

[will.deacon@arm.com (Will Deacon)]

On Thu, Nov 22, 2012 at 11:47:31AM +0000, Marc Zyngier wrote:
> Commit e50c541 (ARM: perf: add guest vs host discrimination) broken the
> link as perf_instruction_pointer and perf_misc_flags are not defined
> when CONFIG_HW_PERF_EVENTS is not selected.
> 
> As it make little sense to try and profile a guest without any HW event,
> just fallback to the original code when this config option is not selected.
> 
> Reported-by: Russell King <linux@arm.linux.org.uk>
> Cc: Will Deacon <will.deacon@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm/include/asm/perf_event.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm/include/asm/perf_event.h b/arch/arm/include/asm/perf_event.h
> index 00416ed..7558775 100644
> --- a/arch/arm/include/asm/perf_event.h
> +++ b/arch/arm/include/asm/perf_event.h
> @@ -21,9 +21,11 @@
>  #define C(_x)				PERF_COUNT_HW_CACHE_##_x
>  #define CACHE_OP_UNSUPPORTED		0xFFFF
>  
> +#ifdef CONFIG_HW_PERF_EVENTS
>  struct pt_regs;
>  extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
>  extern unsigned long perf_misc_flags(struct pt_regs *regs);
>  #define perf_misc_flags(regs)	perf_misc_flags(regs)
> +#endif
>  
>  #endif /* __ARM_PERF_EVENT_H__ */
> -- 

Acked-by: Will Deacon <will.deacon@arm.com>

Thanks Marc for the fix and Russell for reporting the issue.

Please can you stick this in the patch system as I don't have any other
perf patches pending for 3.8?

Will