Re: [PATCH v4 06/10] powerpc/watchpoint: Set CPU_FTR_DAWR1 based on pa-features bit

[Jordan Niethe]

On Fri, Jul 17, 2020 at 2:10 PM Ravi Bangoria
 wrote:
>
> As per the PAPR, bit 0 of byte 64 in pa-features property indicates
> availability of 2nd DAWR registers. i.e. If this bit is set, 2nd
> DAWR is present, otherwise not. Host generally uses "cpu-features",
> which masks "pa-features". But "cpu-features" are still not used for
> guests and thus this change is mostly applicable for guests only.
>
> Signed-off-by: Ravi Bangoria 
I checked those PAPR values are correct and checked running a powernv
kernel in p10 mambo with dt_cpu_ftrs=off and it does set the
CPU_FTR_DAWR1 bit.
(using p10 skiboot).
Tested-by: Jordan Niethe 
> ---
>  arch/powerpc/kernel/prom.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> index 9cc49f265c86..c76c09b97bc8 100644
> --- a/arch/powerpc/kernel/prom.c
> +++ b/arch/powerpc/kernel/prom.c
> @@ -175,6 +175,8 @@ static struct ibm_pa_feature {
>  */
> { .pabyte = 22, .pabit = 0, .cpu_features = CPU_FTR_TM_COMP,
>   .cpu_user_ftrs2 = PPC_FEATURE2_HTM_COMP | 
> PPC_FEATURE2_HTM_NOSC_COMP },
> +
> +   { .pabyte = 64, .pabit = 0, .cpu_features = CPU_FTR_DAWR1 },
>  };
>
>  static void __init scan_features(unsigned long node, const unsigned char 
> *ftrs,
> --
> 2.26.2
>

[PATCH v4 06/10] powerpc/watchpoint: Set CPU_FTR_DAWR1 based on pa-features bit

[Ravi Bangoria]

As per the PAPR, bit 0 of byte 64 in pa-features property indicates
availability of 2nd DAWR registers. i.e. If this bit is set, 2nd
DAWR is present, otherwise not. Host generally uses "cpu-features",
which masks "pa-features". But "cpu-features" are still not used for
guests and thus this change is mostly applicable for guests only.

Signed-off-by: Ravi Bangoria 
---
 arch/powerpc/kernel/prom.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 9cc49f265c86..c76c09b97bc8 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -175,6 +175,8 @@ static struct ibm_pa_feature {
 */
{ .pabyte = 22, .pabit = 0, .cpu_features = CPU_FTR_TM_COMP,
  .cpu_user_ftrs2 = PPC_FEATURE2_HTM_COMP | PPC_FEATURE2_HTM_NOSC_COMP 
},
+
+   { .pabyte = 64, .pabit = 0, .cpu_features = CPU_FTR_DAWR1 },
 };
 
 static void __init scan_features(unsigned long node, const unsigned char *ftrs,
-- 
2.26.2