Re: [PATCH v6 00/15] arm64: Self-hosted trace related errata workarounds

[Suzuki K Poulose]

Hi Mathieu,

On 21/10/2021 18:11, Mathieu Poirier wrote:
> On Thu, 21 Oct 2021 at 10:47, Will Deacon <will@xxxxxxxxxx> wrote:
> > Hi Mathieu,
> >
> > [CC Greg]
> >
> > On Thu, Oct 21, 2021 at 10:35:31AM -0600, Mathieu Poirier wrote:
> > > On Thu, Oct 21, 2021 at 09:53:14AM +0100, Will Deacon wrote:
> > > > On Wed, Oct 20, 2021 at 09:42:07AM -0600, Mathieu Poirier wrote:
> > > > > On Tue, Oct 19, 2021 at 05:31:38PM +0100, Suzuki K Poulose wrote:
> > > > > > Suzuki K Poulose (15):
> > > > > >    arm64: Add Neoverse-N2, Cortex-A710 CPU part definition
> > > > > >    arm64: errata: Add detection for TRBE overwrite in FILL mode
> > > > > >    arm64: errata: Add workaround for TSB flush failures
> > > > > >    arm64: errata: Add detection for TRBE write to out-of-range
> > > > > >    coresight: trbe: Add a helper to calculate the trace generated
> > > > > >    coresight: trbe: Add a helper to pad a given buffer area
> > > > > >    coresight: trbe: Decouple buffer base from the hardware base
> > > > > >    coresight: trbe: Allow driver to choose a different alignment
> > > > > >    coresight: trbe: Add infrastructure for Errata handling
> > > > > >    coresight: trbe: Workaround TRBE errata overwrite in FILL mode
> > > > > >    coresight: trbe: Add a helper to determine the minimum buffer size
> > > > > >    coresight: trbe: Make sure we have enough space
> > > > > >    coresight: trbe: Work around write to out of range
> > > > > >    arm64: errata: Enable workaround for TRBE overwrite in FILL mode
> > > > > >    arm64: errata: Enable TRBE workaround for write to out-of-range
> > > > > >      address
> > > > > >
> > > > > >   Documentation/arm64/silicon-errata.rst       |  12 +
> > > > > >   arch/arm64/Kconfig                           | 111 ++++++
> > > > > >   arch/arm64/include/asm/barrier.h             |  16 +-
> > > > > >   arch/arm64/include/asm/cputype.h             |   4 +
> > > > > >   arch/arm64/kernel/cpu_errata.c               |  64 +++
> > > > > >   arch/arm64/tools/cpucaps                     |   3 +
> > > > > >   drivers/hwtracing/coresight/coresight-trbe.c | 394 +++++++++++++++++--
> > > > > >   7 files changed, 567 insertions(+), 37 deletions(-)
> > > > >
> > > > > I have applied this set.
> > > >
> > > > Mathieu -- the plan here (which we have discussed on the list [1]) is
> > > > for the first four patches to be shared with arm64. Since you've gone
> > > > ahead and applied the whole series, please can you provide me a stable
> > > > branch with the first four patches only so that I can include them in
> > > > the arm64 tree?
> > > >
> > > > Failing that, I can create a branch for you to pull and apply the remaining
> > > > patches on top.
> > > >
> > > > Please let me know.
> > >
> > > Coresight patches flow through Greg's tree and as such the coresight-next tree
> > > gets rebased anyway.  I will remove the first 4 patches and push again.  By the
> > > way do you also want to pick up patches 14 and 16 since they are concerned with
> > > "arch/arm64/Kconfig" or should I keep them?
> >
> > I'll take the first 4 and put them on a stable branch, which you can choose
> > to pull if you like (but please don't rebase it or we'll end up with
> > duplicate commits). The rest of the patches, including the later Kconfig
> > changes, are yours but I doubt they'll apply cleanly without the initial
> > changes.
>
> Right - I just had another look at them and what I suggested above won't work.
>
> > Are you sure Greg rebases everything? That sounds a bit weird to me, as it
> > means it's impossible to share branches with other trees. How do you usually
> > handle this situation?
>
> Greg applies the patches I send to him near the end of every cycle -
> see this one [1] as an example.  Unfortunately that way of working
> makes it hard to deal with patchsets such as this one.
>
> To move forward you can either pick up this whole series (just add my
> RB to all the CS patches) or I start sending pull requests to Greg.

I don't think that may work well, as the CoreSight bits in the series
depend on what is in coresight/next. So this series can't be pulled
in to arm64 without what is already in coresight/next.

Suzuki