linux-toradex.git/arch/powerpc, branch v3.4.53

powerpc: Fix missing/delayed calls to irq_work

2013-06-20T18:58:47+00:00

commit 230b3034793247f61e6a0b08c44cf415f6d92981 upstream.

When replaying interrupts (as a result of the interrupt occurring
while soft-disabled), in the case of the decrementer, we are exclusively
testing for a pending timer target. However we also use decrementer
interrupts to trigger the new "irq_work", which in this case would
be missed.

This change the logic to force a replay in both cases of a timer
boundary reached and a decrementer interrupt having actually occurred
while disabled. The former test is still useful to catch cases where
a CPU having been hard-disabled for a long time completely misses the
interrupt due to a decrementer rollover.

Signed-off-by: Benjamin Herrenschmidt 
Tested-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Fix stack overflow crash in resume_kernel when ftracing

2013-06-20T18:58:47+00:00

commit 0e37739b1c96d65e6433998454985de994383019 upstream.

It's possible for us to crash when running with ftrace enabled, eg:

  Bad kernel stack pointer bffffd12 at c00000000000a454
  cpu 0x3: Vector: 300 (Data Access) at [c00000000ffe3d40]
      pc: c00000000000a454: resume_kernel+0x34/0x60
      lr: c00000000000335c: performance_monitor_common+0x15c/0x180
      sp: bffffd12
     msr: 8000000000001032
     dar: bffffd12
   dsisr: 42000000

If we look at current's stack (paca->__current->stack) we see it is
equal to c0000002ecab0000. Our stack is 16K, and comparing to
paca->kstack (c0000002ecab3e30) we can see that we have overflowed our
kernel stack. This leads to us writing over our struct thread_info, and
in this case we have corrupted thread_info->flags and set
_TIF_EMULATE_STACK_STORE.

Dumping the stack we see:

  3:mon> t c0000002ecab0000
  [c0000002ecab0000] c00000000002131c .performance_monitor_exception+0x5c/0x70
  [c0000002ecab0080] c00000000000335c performance_monitor_common+0x15c/0x180
  --- Exception: f01 (Performance Monitor) at c0000000000fb2ec .trace_hardirqs_off+0x1c/0x30
  [c0000002ecab0370] c00000000016fdb0 .trace_graph_entry+0xb0/0x280 (unreliable)
  [c0000002ecab0410] c00000000003d038 .prepare_ftrace_return+0x98/0x130
  [c0000002ecab04b0] c00000000000a920 .ftrace_graph_caller+0x14/0x28
  [c0000002ecab0520] c0000000000d6b58 .idle_cpu+0x18/0x90
  [c0000002ecab05a0] c00000000000a934 .return_to_handler+0x0/0x34
  [c0000002ecab0620] c00000000001e660 .timer_interrupt+0x160/0x300
  [c0000002ecab06d0] c0000000000025dc decrementer_common+0x15c/0x180
  --- Exception: 901 (Decrementer) at c0000000000104d4 .arch_local_irq_restore+0x74/0xa0
  [c0000002ecab09c0] c0000000000fe044 .trace_hardirqs_on+0x14/0x30 (unreliable)
  [c0000002ecab0fb0] c00000000016fe3c .trace_graph_entry+0x13c/0x280
  [c0000002ecab1050] c00000000003d038 .prepare_ftrace_return+0x98/0x130
  [c0000002ecab10f0] c00000000000a920 .ftrace_graph_caller+0x14/0x28
  [c0000002ecab1160] c0000000000161f0 .__ppc64_runlatch_on+0x10/0x40
  [c0000002ecab11d0] c00000000000a934 .return_to_handler+0x0/0x34
  --- Exception: 901 (Decrementer) at c0000000000104d4 .arch_local_irq_restore+0x74/0xa0

  ... and so on

__ppc64_runlatch_on() is called from RUNLATCH_ON in the exception entry
path. At that point the irq state is not consistent, ie. interrupts are
hard disabled (by the exception entry), but the paca soft-enabled flag
may be out of sync.

This leads to the local_irq_restore() in trace_graph_entry() actually
enabling interrupts, which we do not want. Because we have not yet
reprogrammed the decrementer we immediately take another decrementer
exception, and recurse.

The fix is twofold. Firstly make sure we call DISABLE_INTS before
calling RUNLATCH_ON. The badly named DISABLE_INTS actually reconciles
the irq state in the paca with the hardware, making it safe again to
call local_irq_save/restore().

Although that should be sufficient to fix the bug, we also mark the
runlatch routines as notrace. They are called very early in the
exception entry and we are asking for trouble tracing them. They are
also fairly uninteresting and tracing them just adds unnecessary
overhead.

[ This regression was introduced by fe1952fc0afb9a2e4c79f103c08aef5d13db1873
  "powerpc: Rework runlatch code" by myself --BenH
]

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/eeh: Don't check RTAS token to get PE addr

2013-06-13T16:45:00+00:00

commit b8b3de224f194005ad87ede6fd022fcc2bef3b1a upstream.

RTAS token "ibm,get-config-addr-info" or ibm,get-config-addr-info2"
are used to retrieve the PE address according to PCI address, which
made up of domain/bus/slot/function. If we don't have those 2 tokens,
the domain/bus/slot/function would be used as the address for EEH
RTAS operations. Some older f/w might not have those 2 tokens and
that blocks the EEH functionality to be initialized. It was introduced
by commit e2af155c ("powerpc/eeh: pseries platform EEH initialization").

The patch skips the check on those 2 tokens so we can bring up EEH
functionality successfully. And domain/bus/slot/function will be
used as address for EEH RTAS operations.

Reported-by: Robert Knight 
Signed-off-by: Gavin Shan 
Tested-by: Robert Knight 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Bring all threads online prior to migration/hibernation

2013-05-19T17:54:40+00:00

commit 120496ac2d2d60aee68d3123a68169502a85f4b5 upstream.

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).

Signed-off-by: Robert Jennings 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: fix numa distance for form0 device tree

2013-05-11T20:48:06+00:00

commit 7122beeee7bc1757682049780179d7c216dd1c83 upstream.

The following commit breaks numa distance setup for old powerpc
systems that use form0 encoding in device tree.

commit 41eab6f88f24124df89e38067b3766b7bef06ddb
powerpc/numa: Use form 1 affinity to setup node distance

Device tree node /rtas/ibm,associativity-reference-points would
index into /cpus/PowerPCxxxx/ibm,associativity based on form0 or
form1 encoding detected by ibm,architecture-vec-5 property.

All modern systems use form1 and current kernel code is correct.
However, on older systems with form0 encoding, the numa distance
will get hard coded as LOCAL_DISTANCE for all nodes.  This causes
task scheduling anomaly since scheduler will skip building numa
level domain (topmost domain with all cpus) if all numa distances
are same.  (value of 'level' in sched_init_numa() will remain 0)

Prior to the above commit:
((from) == (to) ? LOCAL_DISTANCE : REMOTE_DISTANCE)

Restoring compatible behavior with this patch for old powerpc systems
with device tree where numa distance are encoded as form0.

Signed-off-by: Vaidyanathan Srinivasan 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc: Emulate non privileged DSCR read and write

2013-05-11T20:48:05+00:00

commit 73d2fb758e678c93bc76d40876c2359f0729b0ef upstream.

POWER8 allows read and write of the DSCR in userspace. We added
kernel emulation so applications could always use the instructions
regardless of the CPU type.

Unfortunately there are two SPRs for the DSCR and we only added
emulation for the privileged one. Add code to match the non
privileged one.

A simple test was created to verify the fix:

http://ozlabs.org/~anton/junkcode/user_dscr_test.c

Without the patch we get a SIGILL and it passes with the patch.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/spufs: Initialise inode->i_ino in spufs_new_inode()

2013-05-08T02:51:52+00:00

commit 6747e83235caecd30b186d1282e4eba7679f81b7 upstream.

In commit 85fe402 (fs: do not assign default i_ino in new_inode), the
initialisation of i_ino was removed from new_inode() and pushed down
into the callers. However spufs_new_inode() was not updated.

This exhibits as no files appearing in /spu, because all our dirents
have a zero inode, which readdir() seems to dislike.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Add isync to copy_and_flush

2013-05-08T02:51:52+00:00

commit 29ce3c5073057991217916abc25628e906911757 upstream.

In __after_prom_start we copy the kernel down to zero in two calls to
copy_and_flush.  After the first call (copy from 0 to copy_to_here:)
we jump to the newly copied code soon after.

Unfortunately there's no isync between the copy of this code and the
jump to it.  Hence it's possible that stale instructions could still be
in the icache or pipeline before we branch to it.

We've seen this on real machines and it's results in no console output
after:
  calling quiesce...
  returning from prom_init

The below adds an isync to ensure that the copy and flushing has
completed before any branching to the new instructions occurs.

Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: pSeries_lpar_hpte_remove fails from Adjunct partition being performed before the ANDCOND test

2013-04-12T16:38:45+00:00

commit 9fb2640159f9d4f5a2a9d60e490482d4cbecafdb upstream.

Some versions of pHyp will perform the adjunct partition test before the
ANDCOND test.  The result of this is that H_RESOURCE can be returned and
cause the BUG_ON condition to occur. The HPTE is not removed.  So add a
check for H_RESOURCE, it is ok if this HPTE is not removed as
pSeries_lpar_hpte_remove is looking for an HPTE to remove and not a
specific HPTE to remove.  So it is ok to just move on to the next slot
and try again.

Signed-off-by: Michael Wolf 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Greg Kroah-Hartman

signal: Define __ARCH_HAS_SA_RESTORER so we know whether to clear sa_restorer

2013-04-05T17:04:14+00:00

Vaguely based on upstream commit 574c4866e33d 'consolidate kernel-side
struct sigaction declarations'.

flush_signal_handlers() needs to know whether sigaction::sa_restorer
is defined, not whether SA_RESTORER is defined.  Define the
__ARCH_HAS_SA_RESTORER macro to indicate this.

Signed-off-by: Ben Hutchings 
Cc: Al Viro 
Signed-off-by: Greg Kroah-Hartman