linux-stable.git/arch/powerpc/kernel/rtas.c, branch v4.0

powerpc/pseries: Fix endian problems with LE migration

2015-01-27T03:03:53+00:00

RTAS events require arguments be passed in big endian while hypercalls
have their arguments passed in registers and the values should therefore
be in CPU endian.

The "ibm,suspend_me" 'RTAS' call makes a sequence of hypercalls to setup
one true RTAS call. This means that "ibm,suspend_me" is handled
specially in the ppc_rtas() syscall.

The ppc_rtas() syscall has its arguments in big endian and can therefore
pass these arguments directly to the RTAS call. "ibm,suspend_me" is
handled specially from within ppc_rtas() (by calling rtas_ibm_suspend_me())
which has left an endian bug on little endian systems due to the
requirement of hypercalls. The return value from rtas_ibm_suspend_me()
gets returned in cpu endian, and is left unconverted, also a bug on
little endian systems.

rtas_ibm_suspend_me() does not actually make use of the rtas_args that
it is passed. This patch removes the convoluted use of the rtas_args
struct to pass params to rtas_ibm_suspend_me() in favour of passing what
it needs as actual arguments. This patch also ensures the two callers of
rtas_ibm_suspend_me() pass function parameters in cpu endian and in the
case of ppc_rtas(), converts the return value.

migrate_store() (the other caller of rtas_ibm_suspend_me()) is from a
sysfs file which deals with everything in cpu endian so this function
only underwent cleanup.

This patch has been tested with KVM both LE and BE and on PowerVM both
LE and BE. Under QEMU/KVM the migration happens without touching these
code pathes.

For PowerVM there is no obvious regression on BE and the LE code path
now provides the correct parameters to the hypervisor.

Signed-off-by: Cyril Bur 
Signed-off-by: Michael Ellerman

powerpc: Remove some old bootmem related comments

2014-11-09T22:59:25+00:00

Now bootmem is gone from powerpc we can remove comments mentioning it.

Signed-off-by: Anton Blanchard 
Tested-by: Emil Medve 
Signed-off-by: Michael Ellerman

of/fdt: update of_get_flat_dt_prop in prep for libfdt

2014-04-30T05:59:15+00:00

Make of_get_flat_dt_prop arguments compatible with libfdt fdt_getprop
call in preparation to convert FDT code to use libfdt. Make the return
value const and the property length ptr type an int.

Signed-off-by: Rob Herring 
Tested-by: Michal Simek 
Tested-by: Grant Likely 
Tested-by: Stephen Chivers

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/le: Big endian arguments for ppc_rtas()

2014-03-23T22:48:36+00:00

The ppc_rtas() syscall allows userspace to interact directly with RTAS.
For the moment, it assumes every thing is big endian and returns either
EINVAL or EFAULT when called in a little endian environment.

As suggested by Benjamin, to avoid bugs when userspace wants to pass
a non 32 bit value to RTAS, it is far better to stick with a simple
rationale: ppc_rtas() should be called with a big endian rtas_args
structure.

With this patch, it is now up to userspace to forge big endian arguments,
as expected by RTAS.

Signed-off-by: Greg Kurz 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Make RTAS calls endian safe

2013-08-14T05:33:22+00:00

RTAS expects arguments in the call buffer to be big endian so we
need to byteswap on little endian builds

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Make RTAS device tree accesses endian safe

2013-08-14T05:33:20+00:00

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Delete __cpuinit usage from all users

2013-07-01T01:10:36+00:00

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

This removes all the powerpc uses of the __cpuinit macros.  There
are no __CPUINIT users in assembly files in powerpc.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Josh Boyer 
Cc: Matt Porter 
Cc: Kumar Gala 
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Paul Gortmaker 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Bring all threads online prior to migration/hibernation

2013-05-14T04:36:29+00:00

This patch brings online all threads which are present but not online
prior to migration/hibernation.  After migration/hibernation those
threads are taken back offline.

During migration/hibernation all online CPUs must call H_JOIN, this is
required by the hypervisor.  Without this patch, threads that are offline
(H_CEDE'd) will not be woken to make the H_JOIN call and the OS will be
deadlocked (all threads either JOIN'd or CEDE'd).

Cc: 
Signed-off-by: Robert Jennings 
Signed-off-by: Benjamin Herrenschmidt

powerpc+of: Remove the pSeries_reconfig.h file

2012-11-15T01:56:55+00:00

Remove the pSeries_reconfig.h header file. At this point there is only one
definition in the file, pSeries_coalesce_init(), which can be
moved to rtas.h.

Signed-off-by: Nathan Fontenot 
Acked-by: Rob Herring 
Acked-by: Grant Likely 
Signed-off-by: Benjamin Herrenschmidt