Revision f32393c943e297b8ae180c8f83d81a156c7d0412 authored by Nathan Fontenot on 30 April 2015, 01:42:06 UTC, committed by Michael Ellerman on 01 May 2015, 03:47:24 UTC
The incorrect ordering of operations during cpu dlpar add results in invalid affinity for the cpu being added. The ibm,associativity property in the device tree is populated with all zeroes for the added cpu which results in invalid affinity mappings and all cpus appear to belong to node 0. This occurs because rtas configure-connector is called prior to making the rtas set-indicator calls. Phyp does not assign affinity information for a cpu until the rtas set-indicator calls are made to set the isolation and allocation state. Correct the order of operations to make the rtas set-indicator calls (done in dlpar_acquire_drc) before calling rtas configure-connector. Fixes: 1a8061c46c46 ("powerpc/pseries: Add kernel based CPU DLPAR handling") Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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irqflags-tracing.txt
IRQ-flags state tracing
started by Ingo Molnar <mingo@redhat.com>
the "irq-flags tracing" feature "traces" hardirq and softirq state, in
that it gives interested subsystems an opportunity to be notified of
every hardirqs-off/hardirqs-on, softirqs-off/softirqs-on event that
happens in the kernel.
CONFIG_TRACE_IRQFLAGS_SUPPORT is needed for CONFIG_PROVE_SPIN_LOCKING
and CONFIG_PROVE_RW_LOCKING to be offered by the generic lock debugging
code. Otherwise only CONFIG_PROVE_MUTEX_LOCKING and
CONFIG_PROVE_RWSEM_LOCKING will be offered on an architecture - these
are locking APIs that are not used in IRQ context. (the one exception
for rwsems is worked around)
architecture support for this is certainly not in the "trivial"
category, because lots of lowlevel assembly code deal with irq-flags
state changes. But an architecture can be irq-flags-tracing enabled in a
rather straightforward and risk-free manner.
Architectures that want to support this need to do a couple of
code-organizational changes first:
- add and enable TRACE_IRQFLAGS_SUPPORT in their arch level Kconfig file
and then a couple of functional changes are needed as well to implement
irq-flags-tracing support:
- in lowlevel entry code add (build-conditional) calls to the
trace_hardirqs_off()/trace_hardirqs_on() functions. The lock validator
closely guards whether the 'real' irq-flags matches the 'virtual'
irq-flags state, and complains loudly (and turns itself off) if the
two do not match. Usually most of the time for arch support for
irq-flags-tracing is spent in this state: look at the lockdep
complaint, try to figure out the assembly code we did not cover yet,
fix and repeat. Once the system has booted up and works without a
lockdep complaint in the irq-flags-tracing functions arch support is
complete.
- if the architecture has non-maskable interrupts then those need to be
excluded from the irq-tracing [and lock validation] mechanism via
lockdep_off()/lockdep_on().
in general there is no risk from having an incomplete irq-flags-tracing
implementation in an architecture: lockdep will detect that and will
turn itself off. I.e. the lock validator will still be reliable. There
should be no crashes due to irq-tracing bugs. (except if the assembly
changes break other code by modifying conditions or registers that
shouldn't be)
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