[RFC Patch 6/6] Adapt kexec and samples code to recognise PPC64 hardware breakpoint usage

[Geert Uytterhoeven]

On Thu, 14 May 2009, K.Prasad wrote:
> Modify kexec code to disable DABR registers before a reboot. Adapt the samples
> code to populate PPC64-arch specific fields.
> 
> Signed-off-by: K.Prasad <prasad at linux.vnet.ibm.com>
> ---
>  arch/powerpc/kernel/machine_kexec_64.c   |    6 
>  samples/hw_breakpoint/data_breakpoint.c  |    4 
> 
> Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/machine_kexec_64.c
> ===================================================================
> --- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/machine_kexec_64.c	2009-05-14 00:17:24.000000000 +0530
> +++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/machine_kexec_64.c	2009-05-14 09:48:09.000000000 +0530
> @@ -24,6 +24,7 @@
>  #include <asm/sections.h>	/* _end */
>  #include <asm/prom.h>
>  #include <asm/smp.h>
> +#include <asm/hw_breakpoint.h>
>  
>  int default_machine_kexec_prepare(struct kimage *image)
>  {
> @@ -214,6 +215,9 @@
>  	put_cpu();
>  
>  	local_irq_disable();
> +#ifdef CONFIG_PPC64
   ^^^^^^^^^^^^^^^^^^^
> +	hw_breakpoint_disable();
> +#endif
   ^^^^^^

What about providing a dummy definition of hw_breakpoint_disable()
in <asm/hw_breakpoint.h> if !CONFIG_PPC64?

and if you make it safe to always include <asm/hw_breakpoint.h>, you can
get rid of the #ifdef in e.g.

--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/ptrace.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c
@@ -37,6 +37,9 @@
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
+#ifdef CONFIG_PPC64
+#include <asm/hw_breakpoint.h>
+#endif

With kind regards,

Geert Uytterhoeven
Software Architect
Techsoft Centre

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