On Thu, Jul 20, 2023 at 04:23:32PM -0700, Easwar Hariharan wrote: > From: Suzuki K Poulose <suzuki.poulose@xxxxxxx> > > commit fa82d0b4b833790ac4572377fb777dcea24a9d69 upstream > > Arm Neoverse-N2 (#2067961) and Cortex-A710 (#2054223) suffers > from errata, where a TSB (trace synchronization barrier) > fails to flush the trace data completely, when executed from > a trace prohibited region. In Linux we always execute it > after we have moved the PE to trace prohibited region. So, > we can apply the workaround every time a TSB is executed. > > The work around is to issue two TSB consecutively. > > NOTE: This errata is defined as LOCAL_CPU_ERRATUM, implying > that a late CPU could be blocked from booting if it is the > first CPU that requires the workaround. This is because we > do not allow setting a cpu_hwcaps after the SMP boot. The > other alternative is to use "this_cpu_has_cap()" instead > of the faster system wide check, which may be a bit of an > overhead, given we may have to do this in nvhe KVM host > before a guest entry. > > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > Cc: Mike Leach <mike.leach@xxxxxxxxxx> > Cc: Mark Rutland <mark.rutland@xxxxxxx> > Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> > Cc: Marc Zyngier <maz@xxxxxxxxxx> > Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> > Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> > Link: https://lore.kernel.org/r/20211019163153.3692640-4-suzuki.poulose@xxxxxxx > Signed-off-by: Will Deacon <will@xxxxxxxxxx> > --- > Documentation/arm64/silicon-errata.rst | 4 ++++ > arch/arm64/Kconfig | 33 ++++++++++++++++++++++++++ > arch/arm64/include/asm/barrier.h | 16 ++++++++++++- > arch/arm64/kernel/cpu_errata.c | 19 +++++++++++++++ > arch/arm64/tools/cpucaps | 1 + > 5 files changed, 72 insertions(+), 1 deletion(-) As you forwarded this patch on to me, you forgot to sign-off on it :( I've taken patch 1/4 of this series, but not the rest. Please redo them, and send the needed backports for 6.1.y and 6.4.y as a separate series (obviously I can't apply patches in a series to trees that already have them.) thanks, greg k-h
