Re: [Qemu-devel] [PATCH 01/13] target/arm: A53: Initialize PMCEID[0]

[Aaron Lindsay <alindsay@codeaurora.org>]

On Oct 09 19:19, Peter Maydell wrote:
> On 19 April 2017 at 18:41, Aaron Lindsay <alindsay@codeaurora.org> wrote:
> > A53 advertises ARM_FEATURE_PMU, but wasn't initializing pmceid[01]
> >
> > Signed-off-by: Aaron Lindsay <alindsay@codeaurora.org>
> > ---
> >  target/arm/cpu.c   | 2 +-
> >  target/arm/cpu64.c | 2 ++
> >  2 files changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> > index 04b062c..921b028 100644
> > --- a/target/arm/cpu.c
> > +++ b/target/arm/cpu.c
> > @@ -1342,7 +1342,7 @@ static void cortex_a15_initfn(Object *obj)
> >      cpu->id_pfr0 = 0x00001131;
> >      cpu->id_pfr1 = 0x00011011;
> >      cpu->id_dfr0 = 0x02010555;
> > -    cpu->pmceid0 = 0x0000000;
> > +    cpu->pmceid0 = 0x00000000;
> >      cpu->pmceid1 = 0x00000000;
> >      cpu->id_afr0 = 0x00000000;
> >      cpu->id_mmfr0 = 0x10201105;
> 
> This is A15 code, which the commit message doesn't say anything about.
> Fixing this code style nit should probably be a separate patch.

I'll split this off for the next version.

> > diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> > index 670c07a..7b1642e 100644
> > --- a/target/arm/cpu64.c
> > +++ b/target/arm/cpu64.c
> > @@ -198,6 +198,8 @@ static void aarch64_a53_initfn(Object *obj)
> >      cpu->id_isar5 = 0x00011121;
> >      cpu->id_aa64pfr0 = 0x00002222;
> >      cpu->id_aa64dfr0 = 0x10305106;
> > +    cpu->pmceid0 = 0x00000000;
> > +    cpu->pmceid1 = 0x00000000;
> >      cpu->id_aa64isar0 = 0x00011120;
> >      cpu->id_aa64mmfr0 = 0x00001122; /* 40 bit physical addr */
> >      cpu->dbgdidr = 0x3516d000;
> 
> Does this actually make a difference? The field values should be 0
> anyway if the CPU-specific initfn doesn't set them to anything.

Perhaps not. I thought the omission was accidental since A15 and A57
both initialize them to zero (added in
4054bfa9e7986c9b7d2bf70f9e10af9647e376fc: "target-arm: Add the pmceid0
and pmceid1 registers")

-Aaron

-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.