linux.git/arch/powerpc/kernel/rtas.c, branch v3.18.64

powerpc/rtas: Validate rtas.entry before calling enter_rtas()

2015-11-15T17:51:47+00:00

[ Upstream commit 8832317f662c06f5c06e638f57bfe89a71c9b266 ]

Currently we do not validate rtas.entry before calling enter_rtas(). This
leads to a kernel oops when user space calls rtas system call on a powernv
platform (see below). This patch adds code to validate rtas.entry before
making enter_rtas() call.

  Oops: Exception in kernel mode, sig: 4 [#1]
  SMP NR_CPUS=1024 NUMA PowerNV
  task: c000000004294b80 ti: c0000007e1a78000 task.ti: c0000007e1a78000
  NIP: 0000000000000000 LR: 0000000000009c14 CTR: c000000000423140
  REGS: c0000007e1a7b920 TRAP: 0e40   Not tainted  (3.18.17-340.el7_1.pkvm3_1_0.2400.1.ppc64le)
  MSR: 1000000000081000   CR: 00000000  XER: 00000000
  CFAR: c000000000009c0c SOFTE: 0
  NIP [0000000000000000]           (null)
  LR [0000000000009c14] 0x9c14
  Call Trace:
  [c0000007e1a7bba0] [c00000000041a7f4] avc_has_perm_noaudit+0x54/0x110 (unreliable)
  [c0000007e1a7bd80] [c00000000002ddc0] ppc_rtas+0x150/0x2d0
  [c0000007e1a7be30] [c000000000009358] syscall_exit+0x0/0x98

Cc: stable@vger.kernel.org # v3.2+
Fixes: 55190f88789a ("powerpc: Add skeleton PowerNV platform")
Reported-by: NAGESWARA R. SASTRY 
Signed-off-by: Vasant Hegde 
[mpe: Reword change log, trim oops, and add stable + fixes]
Signed-off-by: Michael Ellerman 

Signed-off-by: Sasha Levin

powerpc/rtas: Introduce rtas_get_sensor_fast() for IRQ handlers

2015-10-07T14:14:09+00:00

[ Upstream commit 1c2cb594441d02815d304cccec9742ff5c707495 ]

The EPOW interrupt handler uses rtas_get_sensor(), which in turn
uses rtas_busy_delay() to wait for RTAS becoming ready in case it
is necessary. But rtas_busy_delay() is annotated with might_sleep()
and thus may not be used by interrupts handlers like the EPOW handler!
This leads to the following BUG when CONFIG_DEBUG_ATOMIC_SLEEP is
enabled:

 BUG: sleeping function called from invalid context at arch/powerpc/kernel/rtas.c:496
 in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/1
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.2.0-rc2-thuth #6
 Call Trace:
 [c00000007ffe7b90] [c000000000807670] dump_stack+0xa0/0xdc (unreliable)
 [c00000007ffe7bc0] [c0000000000e1f14] ___might_sleep+0x134/0x180
 [c00000007ffe7c20] [c00000000002aec0] rtas_busy_delay+0x30/0xd0
 [c00000007ffe7c50] [c00000000002bde4] rtas_get_sensor+0x74/0xe0
 [c00000007ffe7ce0] [c000000000083264] ras_epow_interrupt+0x44/0x450
 [c00000007ffe7d90] [c000000000120260] handle_irq_event_percpu+0xa0/0x300
 [c00000007ffe7e70] [c000000000120524] handle_irq_event+0x64/0xc0
 [c00000007ffe7eb0] [c000000000124dbc] handle_fasteoi_irq+0xec/0x260
 [c00000007ffe7ef0] [c00000000011f4f0] generic_handle_irq+0x50/0x80
 [c00000007ffe7f20] [c000000000010f3c] __do_irq+0x8c/0x200
 [c00000007ffe7f90] [c0000000000236cc] call_do_irq+0x14/0x24
 [c00000007e6f39e0] [c000000000011144] do_IRQ+0x94/0x110
 [c00000007e6f3a30] [c000000000002594] hardware_interrupt_common+0x114/0x180

Fix this issue by introducing a new rtas_get_sensor_fast() function
that does not use rtas_busy_delay() - and thus can only be used for
sensors that do not cause a BUSY condition - known as "fast" sensors.

The EPOW sensor is defined to be "fast" in sPAPR - mpe.

Fixes: 587f83e8dd50 ("powerpc/pseries: Use rtas_get_sensor in RAS code")
Signed-off-by: Thomas Huth 
Reviewed-by: Nathan Fontenot 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin

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