powerpc/iommu: Prevent false TCE leak message

When a device DMA window includes the address 0, it's reserved in the
TCE bitmap to avoid returning that address to drivers.

When the device is removed, the bitmap is checked for any mappings not
removed by the driver, indicating a possible DMA mapping leak. Since the
reserved address is not cleared, a message is printed, warning of such a
leak.

Check for the reservation, and clear it before checking for any other
standing mappings.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 7f966d394d6630313e02679de1875f67978f8bdd)
powerpc/eeh/of: Checking for CONFIG_EEH is not needed

The functions used are already defined as empty inline functions for the
case where EEH is disabled.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Acked-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit d35d1424045df0a8ce125c7de59b4e7ad3c873fb)
powerpc/eeh: Fix crash when adding a device in a slot with DDW

The DDW code uses a eeh_dev struct from the pci_dev. However, this is
not set until eeh_add_device_late is called.

Since pci_bus_add_devices is called before eeh_add_device_late, the PCI
devices are added to the bus, making drivers' probe hooks to be called.
These will call set_dma_mask, which will call the DDW code, which will
require the eeh_dev struct from pci_dev. This would result in a crash,
due to a NULL dereference.

Calling eeh_add_device_late after pci_bus_add_devices would make the
system BUG, because device files shouldn't be added to devices there
were not added to the system. So, a new function is needed to add such
files only after pci_bus_add_devices have been called.

Cc: stable@vger.kernel.org
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Acked-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 6a040ce72598159a74969a2d01ab0ba5ee6536b3)
powerpc: Make room in exception vector area

The FWNMI region is fixed at 0x7000 and the vector are now
overflowing that with some configurations. Fix that by moving
some hash management code out of that region as it doesn't need
to be that close to the call sites (isn't accessed using
conditional branches).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 61383407677aef05928541a00678591abea2d84c)
powerpc: Add DSCR support to ptrace

The DSCR (aka Data Stream Control Register) is supported on some
server PowerPC chips and allow some control over the prefetch
of data streams.

The kernel already supports DSCR value per thread but there is also
a need in a ability to change it from an external process for
the specific pid.

The patch adds new register index PT_DSCR (index=44) which can be
set/get by:
  ptrace(PTRACE_POKEUSER, traced_process, PT_DSCR << 3, dscr);
  dscr = ptrace(PTRACE_PEEKUSER, traced_process, PT_DSCR << 3, NULL);

The patch does not increase PT_REGS_COUNT as the pt_regs struct has not
been changed.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 1715a826a5b72d4fb882504d0babcea9aec8a0db)

Conflicts:
	arch/powerpc/include/uapi/asm/ptrace.h
powerpc: Fix typo in breakpoint kgdb code.

Currently we are getting:
 arch/powerpc/kernel/kgdb.c: In function 'kgdb_arch_exit':
 arch/powerpc/kernel/kgdb.c:492:2: error: '__debugger_breakx_match' undeclared (first use in this function)
 arch/powerpc/kernel/kgdb.c:492:2: note: each undeclared identifier is reported only once for each function it appears in

Fix the typo.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit fa5924640341f714af7757194d5da7ecd66abe2b)
powerpc: Rename set_break to avoid naming conflict

With allmodconfig we are getting:
  drivers/tty/synclink_gt.c:160:12: error: conflicting types for 'set_break'
  arch/powerpc/include/asm/debug.h:49:5: note: previous declaration of 'set_break' was here

  drivers/tty/synclinkmp.c:526:12: error: conflicting types for 'set_break'
  arch/powerpc/include/asm/debug.h:49:5: note: previous declaration of 'set_break' was here

This renames set_break to set_breakpoint to avoid this naming conflict

Signed-off-by: Michael Neuling <mikey@neuling.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit b9818c3312da66f4b83a4a2e8650628be1237cb5)

Conflicts:
	arch/powerpc/include/asm/debug.h
powerpc/ptrace: Make #defines for all request numbers hex

We have a mix of decimal and hex here, so lets make them consistently
hex.  Also, strace will print them in hex if it can't decode them, so
having them in hex here makes it easier to match up.

No functional change.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 145c52d5ce304f93e15f6a0b4471b2ffae37b3a8)

Conflicts:
	arch/powerpc/include/uapi/asm/ptrace.h
powerpc: Avoid debug_smp_processor_id() check in SHARED_PROCESSOR

Use local_paca directly in macro SHARED_PROCESSOR, as all processors
have the same value for the field shared_proc, so we don't need care
racy here.

Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 94c95cfbfe784eca5f4b96955e41bda1318605bc)
powerpc: Add length setting to set_dawr

Currently we set the length field in the DAWR to 0 which defaults it to one
double word (64bits) which is the same as the DABR.

Change this so that we can set it to longer values as supported by the DAWR.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 05d694ea0daa2e442191a2128aaec78635823f08)
powerpc: Change hardware breakpoint to allow longer ranges

Change the hardware breakpoint code so that we can support wider ranged
breakpoints.

This means both ptrace and perf hardware breakpoints can use upto 512 byte long
breakpoints when using the DAWR and only 8 byte when using the DABR.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 4ae7ebe9522a9e3626e28b4d268dae712738573d)
pseries/iommu: Fix iteration in DDW TCE clearrange

tce_clearrange_multi_pSeriesLP is attempting to iterate over all TCEs in
a given range. However, is it not advancing the dma_offset value passed
to plpar_tce_stuff via the next value. This prevents DLPAR from
completing, because TCEs are still present at slot isolation time.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 22b382985a2e213e4ea0b4e436df24ab7228961d)
pseries/iommu: Ensure TCEs are cleared with non-huge DDW

There are now two kinds of DMA windows that might be presented by
PowerVM DDW support -- huge windows (that can map all of system memory
regardless of the LPAR configuration) and non-huge windows (which
can't). They are implemented slightly differently in PowerVM, and thus
have different characteristics. The most obvious is that slot isolate
doesn't clear the TCEs/window for us with non-huge windows. Thus, when a
DLPAR operation occurs on a slot using a non-huge window, TCEs are still
present (the notifier chain doesn't currently remove them explicitly)
and the DLPAR fails. Fix this by calling remove_ddw() first, which will
unmap the DDW TCEs.

Note: a corresponding change to drmgr is needed to actually successfully
DLPAR, such that the device-tree update (which causes the notifier chain
to fire) occurs before slot isolate.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 71cf1def1ad8384d5fa008f96de94b36668e5460)

Conflicts:
	arch/powerpc/platforms/pseries/iommu.c
powerpc/pseries/iommu: remove default window before attempting DDW manipulation

An upcoming release of firmware will add DDW extensions, in particular
an API to "reset" the DMA window to the original configuration (32-bit,
2GB in size). With that API available, we can safely remove the default
window, increasing the resources available to firmware for creation of
larger windows for the slot in question -- if we encounter an error, we
can use the new API to reset the state of the slot.

Further, this same release of firmware will make it a hard requirement
for OSes to release the existing window before any other windows will be
shown as available, to avoid conflicts in addressing between the two
windows.

In anticipation of these changes, always remove the default window
before we do any DDW manipulations.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 25ebc45b93452d0bc60271f178237123c4b26808)
pseries/iommu: Restore_default_window does not use liobn parameter

The parameter is unused, and complicates a following fix. Just remove
it.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit a1dabadebb5731a6222bd6073e2770f0d0d13b73)
pseries/iommu: Remove DDW on kexec

pseries/iommu: remove DDW on kexec

We currently insert a property in the device-tree when we successfully
configure DDW for a given slot. This was meant to be an optimization to
speed up kexec/kdump, so that we don't need to make the RTAS calls again
to re-configured DDW in the new kernel.

However, we end up tripping a plpar_tce_stuff failure on kexec/kdump
because we unconditionally parse the ibm,dma-window property for the
node at bus/dev setup time. This property contains the 32-bit DMA window
LIOBN, which is distinct from the DDW window's. We pass that LIOBN (via
iommu_table_init -> iommu_table_clear -> tce_free ->
tce_freemulti_pSeriesLP) to plpar_tce_stuff, which fails because that
32-bit window is no longer present after
25ebc45b93452d0bc60271f178237123c4b26808 ("powerpc/pseries/iommu: remove
default window before attempting DDW manipulation").

I believe the simplest, easiest-to-maintain fix is to just change our
initcall to, rather than detecting and updating the new kernel's DDW
knowledge, just remove all DDW configurations. When the drivers
re-initialize, we will set everything back up as it was before.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 14b6f00f8a4fdec5ccd45a0710284de301a61628)
powerpc: Add support for context switching the TAR register

This patch adds support for enabling and context switching the Target
Address Register in Power8. The TAR is a new special purpose register
that can be used for computed branches with the bctar[l] (branch
conditional to TAR) instruction in the same manner as the count and link
registers.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 2468dcf641e4f3e1b0153e3e11ca20740b2f4ce8)
powerpc: Remove Cell-specific relocation-on interrupt vector code

The Cell processor doesn't support relocation-on interrupts, so we
don't need relocation-on versions of the interrupt vectors that are
purely Cell-specific.  This removes them.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 6100209bf6632d908ebcdab339a83f2e083b94e7)
powerpc: Save CFAR before branching in interrupt entry paths

Some of the interrupt vectors on 64-bit POWER server processors are
only 32 bytes long, which is not enough for the full first-level
interrupt handler.  For these we currently just have a branch to an
out-of-line handler.  However, this means that we corrupt the CFAR
(come-from address register) on POWER7 and later processors.

To fix this, we split the EXCEPTION_PROLOG_1 macro into two pieces:
EXCEPTION_PROLOG_0 contains the part up to the point where the CFAR
is saved in the PACA, and EXCEPTION_PROLOG_1 contains the rest.  We
then put EXCEPTION_PROLOG_0 in the short interrupt vectors before
we branch to the out-of-line handler, which contains the rest of the
first-level interrupt handler.  To facilitate this, we define new
_OOL (out of line) variants of STD_EXCEPTION_PSERIES, etc.

In order to get EXCEPTION_PROLOG_0 to be short enough, i.e., no more
than 6 instructions, it was necessary to move the stores that move
the PPR and CFAR values into the PACA into __EXCEPTION_PROLOG_1 and
to get rid of one of the two HMT_MEDIUM instructions.  Previously
there was a HMT_MEDIUM_PPR_DISCARD before the prolog, which was
nop'd out on processors with the PPR (POWER7 and later), and then
another HMT_MEDIUM inside the HMT_MEDIUM_PPR_SAVE macro call inside
__EXCEPTION_PROLOG_1, which was nop'd out on processors without PPR.
Now the HMT_MEDIUM inside EXCEPTION_PROLOG_0 is there unconditionally
and the HMT_MEDIUM_PPR_DISCARD is not strictly necessary, although
this leaves it in for the interrupt vectors where there is room for
it.

Previously we had a handler for hypervisor maintenance interrupts at
0xe50, which doesn't leave enough room for the vector for hypervisor
emulation assist interrupts at 0xe40, since we need 8 instructions.
The 0xe50 vector was only used on POWER6, as the HMI vector was moved
to 0xe60 on POWER7.  Since we don't support running in hypervisor mode
on POWER6, we just remove the handler at 0xe50.

This also changes denorm_exception_hv to use EXCEPTION_PROLOG_0
instead of open-coding it, and removes the HMT_MEDIUM_PPR_DISCARD
from the relocation-on vectors (since any CPU that supports
relocation-on interrupts also has the PPR).

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 1707dd161349e6c54170c88d94fed012e3d224e3)

Conflicts:
	arch/powerpc/kernel/exceptions-64s.S
powerpc: Move boot_paca into early_setup

The powerpc boot_paca symbol is now only used within the
early_setup() routine, so move it from its global definition
into early_setup().

Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 6a7e406419d8b176efbc5be41a82299025ad1b43)