[PULL][Zesty] Errata workarounds for arm_arch_timer

[dann frazier]

On Fri, Mar 24, 2017 at 10:53 AM, dann frazier
<dann.frazier at canonical.com> wrote:
> On Fri, Mar 24, 2017 at 8:02 AM, Seth Forshee
> <seth.forshee at canonical.com> wrote:
>> On Thu, Mar 23, 2017 at 08:17:31PM -0600, dann frazier wrote:
>> +static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type type,
>> +                                           void *arg)
>> +{
>> +       const struct arch_timer_erratum_workaround *wa;
>> +       ate_match_fn_t match_fn = NULL;
>> +
>> +       if (static_branch_unlikely(&arch_timer_read_ool_enabled))
>> +               return;
>> +
>> +       switch (type) {
>> +       case ate_match_dt:
>> +               match_fn = arch_timer_check_dt_erratum;
>> +               break;
>> +       }
>> +
>> +       wa = arch_timer_iterate_errata(type, match_fn, arg);
>> +       if (!wa)
>> +               return;
>> +
>> +       arch_timer_enable_workaround(wa);
>> +       pr_info("Enabling global workaround for %s\n", wa->desc);
>> +}
>>
>> This function makes me uncomfortable, because match_fn could conceivably
>> be NULL when arch_timer_iterate_errata() is called, and that function
>> doesn't check for NULL (I suspect that the initialization of match_fn to
>> NULL is here was added just to silence a compiler warning).  Not that it
>> looks like any of the callers ultimately end up calling it in a way
>> where it end up NULL, but it's not difficult to imagine that happening.
>
> *nod*
>
>> I'd feel a lot better about it if the switch had a default case which
>> just returned and possibly provided a warning, or something like that.
>
> OK - I'll send that feedback upstream

https://www.spinics.net/lists/arm-kernel/msg571641.html

> and implement a local version of that suggestion for my series.

Added to my branch, updated PR follows:

The following changes since commit 0cf75d7435609372dc1e3c2f32c4cb82a10189ce:

  pinctrl: intel: Add Intel Gemini Lake pin controller support
(2017-03-22 09:23:38 -0600)

are available in the git repository at:

  git://git.launchpad.net/~dannf/ubuntu/+source/linux/+git/linux
arm_arch_timer-erratum

for you to fetch changes up to c44a74f77937503a51c44cc870f57016a58813f7:

  UBUNTU: SAUCE: arm64: arch_timer: Add check for unknown erratum
(2017-03-24 13:59:23 -0600)

----------------------------------------------------------------
Marc Zyngier (18):
      UBUNTU: SAUCE: arm64: Allow checking of a CPU-local erratum
      UBUNTU: SAUCE: arm64: Add CNTVCT_EL0 trap handler
      UBUNTU: SAUCE: arm64: Define Cortex-A73 MIDR
      UBUNTU: SAUCE: arm64: cpu_errata: Allow an erratum to be match
for all revisions of a core
      UBUNTU: SAUCE: arm64: cpu_errata: Add capability to advertise
Cortex-A73 erratum 858921
      UBUNTU: SAUCE: arm64: arch_timer: Add infrastructure for
multiple erratum detection methods
      UBUNTU: SAUCE: arm64: arch_timer: Add erratum handler for
globally defined capability
      UBUNTU: SAUCE: arm64: arch_timer: Add erratum handler for
CPU-specific capability
      UBUNTU: SAUCE: arm64: arch_timer: Move arch_timer_reg_read/write around
      UBUNTU: SAUCE: arm64: arch_timer: Get rid of erratum_workaround_set_sne
      UBUNTU: SAUCE: arm64: arch_timer: Rework the set_next_event workarounds
      UBUNTU: SAUCE: arm64: arch_timer: Make workaround methods optional
      UBUNTU: SAUCE: arm64: arch_timer: Allows a CPU-specific erratum
to only affect a subset of CPUs
      UBUNTU: SAUCE: arm64: arch_timer: Move clocksource_counter and co around
      UBUNTU: SAUCE: arm64: arch_timer: Enable CNTVCT_EL0 trap if
workaround is enabled
      UBUNTU: SAUCE: arm64: arch_timer: Workaround for Cortex-A73 erratum 858921
      UBUNTU: SAUCE: arm64: arch_timer: Allow erratum matching with
ACPI OEM information
      UBUNTU: SAUCE: arm64: arch_timer: Add
HISILICON_ERRATUM_161010101 ACPI matching data

Mark Rutland (1):
      arm64: ptrace: add XZR-safe regs accessors

dann frazier (2):
      UBUNTU: [Config] CONFIG_ARM64_ERRATUM_858921=y
      UBUNTU: SAUCE: arm64: arch_timer: Add check for unknown erratum

 Documentation/arm64/silicon-errata.txt    |   1 +
 arch/arm64/include/asm/arch_timer.h       |  44 ++-
 arch/arm64/include/asm/cpucaps.h          |   3 +-
 arch/arm64/include/asm/cputype.h          |   2 +
 arch/arm64/include/asm/esr.h              |   2 +
 arch/arm64/include/asm/ptrace.h           |  20 ++
 arch/arm64/kernel/cpu_errata.c            |  15 +
 arch/arm64/kernel/cpufeature.c            |  13 +-
 arch/arm64/kernel/traps.c                 |  14 +
 debian.master/config/annotations          |   2 +
 debian.master/config/config.common.ubuntu |   1 +
 drivers/clocksource/Kconfig               |  11 +
 drivers/clocksource/arm_arch_timer.c      | 538
+++++++++++++++++++++++++-----------
 13 files changed, 497 insertions(+), 169 deletions(-)