Re: [PATCH 2/2] [PowerPC Book3E] Introduce new ptrace debug feature flag

[David Gibson <dwg@au1.ibm.com>]

On Fri, Aug 19, 2011 at 01:23:38PM +0530, K.Prasad wrote:
> 
> While PPC_PTRACE_SETHWDEBUG ptrace flag in PowerPC accepts
> PPC_BREAKPOINT_MODE_EXACT mode of breakpoint, the same is not intimated to the
> user-space debuggers (like GDB) who may want to use it. Hence we introduce a
> new PPC_DEBUG_FEATURE_DATA_BP_EXACT flag which will be populated on the
> "features" member of "struct ppc_debug_info" to advertise support for the
> same on Book3E PowerPC processors.

I thought the idea was that the BP_EXACT mode was the default - if the
new interface was supported at all, then BP_EXACT was always
supported.  So, why do you need a new flag?

> 
> Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/ptrace.h |    1 +
>  arch/powerpc/kernel/ptrace.c      |    1 +
>  2 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
> index 48223f9..cf014f9 100644
> --- a/arch/powerpc/include/asm/ptrace.h
> +++ b/arch/powerpc/include/asm/ptrace.h
> @@ -380,6 +380,7 @@ struct ppc_debug_info {
>  #define PPC_DEBUG_FEATURE_INSN_BP_MASK		0x0000000000000002
>  #define PPC_DEBUG_FEATURE_DATA_BP_RANGE		0x0000000000000004
>  #define PPC_DEBUG_FEATURE_DATA_BP_MASK		0x0000000000000008
> +#define PPC_DEBUG_FEATURE_DATA_BP_EXACT		0x0000000000000010
>  
>  #ifndef __ASSEMBLY__
>  
> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> index 18d28b6..71db5a6 100644
> --- a/arch/powerpc/kernel/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace.c
> @@ -1636,6 +1636,7 @@ long arch_ptrace(struct task_struct *child, long request,
>  #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
>  		dbginfo.features |=
>  				   PPC_DEBUG_FEATURE_DATA_BP_RANGE |
> +				   PPC_DEBUG_FEATURE_DATA_BP_EXACT |
>  				   PPC_DEBUG_FEATURE_DATA_BP_MASK;
>  #endif
>  #else /* !CONFIG_PPC_ADV_DEBUG_REGS */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson