linux-toradex.git/arch/powerpc/kernel/rtasd.c, branch v4.14

powerpc: Only obtain cpu_hotplug_lock if called by rtasd

2017-06-23T07:32:11+00:00

Calling arch_update_cpu_topology from a CPU hotplug state machine callback
hits a deadlock because the function tries to get a read lock on
cpu_hotplug_lock while the state machine still holds a write lock on it.

Since all callers of arch_update_cpu_topology except rtasd already hold
cpu_hotplug_lock, this patch changes the function to use
stop_machine_cpuslocked and creates a separate function for rtasd which
still tries to obtain the lock.

Michael Bringmann investigated the bug and provided a detailed analysis
of the deadlock on this previous RFC for an alternate solution:

Signed-off-by: Thiago Jung Bauermann 
Signed-off-by: Thomas Gleixner 
Acked-by: Michael Ellerman 
Cc: John Allen 
Cc: Michael Bringmann 
Cc: Nathan Fontenot 
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1497996510-4032-1-git-send-email-bauerman@linux.vnet.ibm.com
Link: https://patchwork.ozlabs.org/patch/771293/

powerpc/pseries: Update affinity for memory and cpus specified in a PRRN event

2017-02-02T09:36:38+00:00

Extend the existing PRRN infrastructure to perform the actual affinity
updating for cpus and memory in addition to the device tree updating.
For cpus, dynamic affinity updating already appears to exist in the
kernel in the form of arch_update_cpu_topology(). For memory, we must
place a READD operation on the hotplug queue for any phandle included in
the PRRN event that is determined to be an LMB.

Signed-off-by: John Allen 
Reviewed-by: Nathan Fontenot 
Signed-off-by: Michael Ellerman

Replace with globally

2016-12-24T19:46:01+00:00

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*'
  sed -i -e "s!$PATT!#include !" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro 
Signed-off-by: Linus Torvalds

powerpc/pseries: start rtasd before PCI probing

2016-07-08T09:22:15+00:00

A strange behaviour is observed when comparing PCI hotplug in QEMU, between
x86 and pseries. If you consider the following steps:
- start a VM
- add a PCI device via the QEMU monitor before the rtasd has started (for
  example starting the VM in paused state, or hotplug during FW or boot
  loader)
- resume the VM execution

The x86 kernel detects the PCI device, but the pseries one does not.

This happens because the rtasd kernel worker is currently started under
device_initcall, while PCI probing happens earlier under subsys_initcall.

As a consequence, if we have a pending RTAS event at boot time, a message
is printed and the event is dropped.

This patch moves all the initialization of rtasd to arch_initcall, which is
run before subsys_call: this way, logging_enabled is true when the RTAS
event pops up and it is not lost anymore.

The proc fs bits stay at device_initcall because they cannot be run before
fs_initcall.

Signed-off-by: Greg Kurz 
Signed-off-by: Michael Ellerman

powerpc/pseries: Fix trivial typo in function name

2016-06-14T06:05:35+00:00

Signed-off-by: Greg Kurz 
Signed-off-by: Michael Ellerman

powerpc: sparse: static-ify some things

2016-04-12T11:05:18+00:00

As sparse suggests, these should be made static.

Signed-off-by: Daniel Axtens 
Reviewed-by: Andrew Donnellan 
Reviewed-by: Stewart Smith 
Signed-off-by: Michael Ellerman

param: convert some "on"/"off" users to strtobool

2016-03-17T22:09:34+00:00

This changes several users of manual "on"/"off" parsing to use
strtobool.

Some side-effects:
- these uses will now parse y/n/1/0 meaningfully too
- the early_param uses will now bubble up parse errors

Signed-off-by: Kees Cook 
Acked-by: Heiko Carstens 
Acked-by: Michael Ellerman 
Cc: Amitkumar Karwar 
Cc: Andy Shevchenko 
Cc: Daniel Borkmann 
Cc: Joe Perches 
Cc: Kalle Valo 
Cc: Martin Schwidefsky 
Cc: Nishant Sarmukadam 
Cc: Rasmus Villemoes 
Cc: Steve French 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

powerpc: Make a bunch of things static

2014-09-25T13:14:41+00:00

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc/le: Enable RTAS events support

2014-04-07T00:33:12+00:00

The current kernel code assumes big endian and parses RTAS events all
wrong. The most visible effect is that we cannot honor EPOW events,
meaning, for example, we cannot shut down a guest properly from the
hypervisor.

This new patch is largely inspired by Nathan's work: we get rid of all
the bit fields in the RTAS event structures (even the unused ones, for
consistency). We also introduce endian safe accessors for the fields used
by the kernel (trivial rtas_error_type() accessor added for consistency).

Cc: Nathan Fontenot 
Signed-off-by: Greg Kurz 
Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Add /proc interface to control topology updates

2013-04-26T06:08:26+00:00

There are instances in which we do not want topology updates to occur.
In order to allow this a /proc interface (/proc/powerpc/topology_updates)
is introduced so that topology updates can be enabled and disabled.

This patch also adds a prrn_is_enabled() call so that PRRN events are
handled in the kernel only if topology updating is enabled.

Signed-off-by: Nathan Fontenot 
Signed-off-by: Benjamin Herrenschmidt