There are two concepts that have some confusing naming:
 1. Extended State Component numbers (currently called
    XFEATURE_BIT_*)
 2. Extended State Component masks (currently called XSTATE_*)

The numbers are (currently) from 0-9.  State component 3 is the
bounds registers for MPX, for instance.

But when we want to enable "state component 3", we go set a bit
in XCR0.  The bit we set is 1<<3.  We can check to see if a
state component feature is enabled by looking at its bit.

The current 'xfeature_bit's are at best xfeature bit _numbers_.
Calling them bits is at best inconsistent with ending the enum
list with 'XFEATURES_NR_MAX'.

This patch renames the enum to be 'xfeature'.  These also
happen to be what the Intel documentation calls a "state
component".

We also want to differentiate these from the "XSTATE_*" macros.
The "XSTATE_*" macros are a mask, and we rename them to match.

These macros are reasonably widely used so this patch is a
wee bit big, but this really is just a rename.

The only non-mechanical part of this is the

	s/XSTATE_EXTEND_MASK/XFEATURE_MASK_EXTEND/

We need a better name for it, but that's another patch.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233126.38653250@viggo.jf.intel.com
[ Ported to v4.3-rc1. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

LightWeight Profiling was evidently an AMD profiling feature
that we never got around to implementing.  Remove the references
to it.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233125.7E602284@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The original purpose of XSTATE_RESERVE was to carve out space
to store all of the possible extended state components that
get saved with the XSAVE instruction(s).

However, we are now almost entirely dynamically allocating
the buffers we use for XSAVE by placing them at the end of
the task_struct and them sizing them at boot.  The one
exception for that is the init_task.

The maximum extended state component size that we have today
is on systems with space for AVX-512 and Memory Protection
Keys: 2696 bytes.  We have reserved a PAGE_SIZE buffer in
the init_task via fpregs_state->__padding.

This check ensures that even if the component sizes or
layout were changed (which we do not expect), that we will
still not overflow the init_task's buffer.

In the case that we detect we might overflow the buffer,
we completely disable XSAVE support in the kernel and try
to boot as if we had 'legacy x87 FPU' support in place.
This is a crippled state without any of the XSAVE-enabled
features (MPX, AVX, etc...).  But, it at least let us
boot safely.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233125.D948D475@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When we want to _completely_ disable XSAVE support as far as
the kernel is concerned, we have a big set of feature flags
to clear.  We currently only do this in cases where the user
asks for it to be disabled, but we are about to expand the
places where we do it to handle errors too.

Move the code in to xstate.c, and put it in the xstate.h
header.  We will use it in the next patch too.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233124.EA9A70E5@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This is utterly a personal taste thing, but I find it way easier
to read structure sizes in decimal than in hex.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233124.1A8B04A8@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Newer bitfiles needs the reduced clk even for SMP builds

Cc: <stable@vger.kernel.org>  #4.2
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Here is an implementation of a new system call, sys_membarrier(), which
executes a memory barrier on all threads running on the system.  It is
implemented by calling synchronize_sched().  It can be used to
distribute the cost of user-space memory barriers asymmetrically by
transforming pairs of memory barriers into pairs consisting of
sys_membarrier() and a compiler barrier.  For synchronization primitives
that distinguish between read-side and write-side (e.g.  userspace RCU
[1], rwlocks), the read-side can be accelerated significantly by moving
the bulk of the memory barrier overhead to the write-side.

The existing applications of which I am aware that would be improved by
this system call are as follows:

* Through Userspace RCU library (http://urcu.so)
  - DNS server (Knot DNS) https://www.knot-dns.cz/
  - Network sniffer (http://netsniff-ng.org/)
  - Distributed object storage (https://sheepdog.github.io/sheepdog/)
  - User-space tracing (http://lttng.org)
  - Network storage system (https://www.gluster.org/)
  - Virtual routers (https://events.linuxfoundation.org/sites/events/files/slides/DPDK_RCU_0MQ.pdf)
  - Financial software (https://lkml.org/lkml/2015/3/23/189)

Those projects use RCU in userspace to increase read-side speed and
scalability compared to locking.  Especially in the case of RCU used by
libraries, sys_membarrier can speed up the read-side by moving the bulk of
the memory barrier cost to synchronize_rcu().

* Direct users of sys_membarrier
  - core dotnet garbage collector (https://github.com/dotnet/coreclr/issues/198)

Microsoft core dotnet GC developers are planning to use the mprotect()
side-effect of issuing memory barriers through IPIs as a way to implement
Windows FlushProcessWriteBuffers() on Linux.  They are referring to
sys_membarrier in their github thread, specifically stating that
sys_membarrier() is what they are looking for.

To explain the benefit of this scheme, let's introduce two example threads:

Thread A (non-frequent, e.g. executing liburcu synchronize_rcu())
Thread B (frequent, e.g. executing liburcu
rcu_read_lock()/rcu_read_unlock())

In a scheme where all smp_mb() in thread A are ordering memory accesses
with respect to smp_mb() present in Thread B, we can change each
smp_mb() within Thread A into calls to sys_membarrier() and each
smp_mb() within Thread B into compiler barriers "barrier()".

Before the change, we had, for each smp_mb() pairs:

Thread A                    Thread B
previous mem accesses       previous mem accesses
smp_mb()                    smp_mb()
following mem accesses      following mem accesses

After the change, these pairs become:

Thread A                    Thread B
prev mem accesses           prev mem accesses
sys_membarrier()            barrier()
follow mem accesses         follow mem accesses

As we can see, there are two possible scenarios: either Thread B memory
accesses do not happen concurrently with Thread A accesses (1), or they
do (2).

1) Non-concurrent Thread A vs Thread B accesses:

Thread A                    Thread B
prev mem accesses
sys_membarrier()
follow mem accesses
                            prev mem accesses
                            barrier()
                            follow mem accesses

In this case, thread B accesses will be weakly ordered. This is OK,
because at that point, thread A is not particularly interested in
ordering them with respect to its own accesses.

2) Concurrent Thread A vs Thread B accesses

Thread A                    Thread B
prev mem accesses           prev mem accesses
sys_membarrier()            barrier()
follow mem accesses         follow mem accesses

In this case, thread B accesses, which are ensured to be in program
order thanks to the compiler barrier, will be "upgraded" to full
smp_mb() by synchronize_sched().

* Benchmarks

On Intel Xeon E5405 (8 cores)
(one thread is calling sys_membarrier, the other 7 threads are busy
looping)

1000 non-expedited sys_membarrier calls in 33s =3D 33 milliseconds/call.

* User-space user of this system call: Userspace RCU library

Both the signal-based and the sys_membarrier userspace RCU schemes
permit us to remove the memory barrier from the userspace RCU
rcu_read_lock() and rcu_read_unlock() primitives, thus significantly
accelerating them. These memory barriers are replaced by compiler
barriers on the read-side, and all matching memory barriers on the
write-side are turned into an invocation of a memory barrier on all
active threads in the process. By letting the kernel perform this
synchronization rather than dumbly sending a signal to every process
threads (as we currently do), we diminish the number of unnecessary wake
ups and only issue the memory barriers on active threads. Non-running
threads do not need to execute such barrier anyway, because these are
implied by the scheduler context switches.

Results in liburcu:

Operations in 10s, 6 readers, 2 writers:

memory barriers in reader:    1701557485 reads, 2202847 writes
signal-based scheme:          9830061167 reads,    6700 writes
sys_membarrier:               9952759104 reads,     425 writes
sys_membarrier (dyn. check):  7970328887 reads,     425 writes

The dynamic sys_membarrier availability check adds some overhead to
the read-side compared to the signal-based scheme, but besides that,
sys_membarrier slightly outperforms the signal-based scheme. However,
this non-expedited sys_membarrier implementation has a much slower grace
period than signal and memory barrier schemes.

Besides diminishing the number of wake-ups, one major advantage of the
membarrier system call over the signal-based scheme is that it does not
need to reserve a signal. This plays much more nicely with libraries,
and with processes injected into for tracing purposes, for which we
cannot expect that signals will be unused by the application.

An expedited version of this system call can be added later on to speed
up the grace period. Its implementation will likely depend on reading
the cpu_curr()->mm without holding each CPU's rq lock.

This patch adds the system call to x86 and to asm-generic.

[1] http://urcu.so

membarrier(2) man page:

MEMBARRIER(2)              Linux Programmer's Manual             MEMBARRIER(2)

NAME
       membarrier - issue memory barriers on a set of threads

SYNOPSIS
       #include <linux/membarrier.h>

       int membarrier(int cmd, int flags);

DESCRIPTION
       The cmd argument is one of the following:

       MEMBARRIER_CMD_QUERY
              Query  the  set  of  supported commands. It returns a bitmask of
              supported commands.

       MEMBARRIER_CMD_SHARED
              Execute a memory barrier on all threads running on  the  system.
              Upon  return from system call, the caller thread is ensured that
              all running threads have passed through a state where all memory
              accesses  to  user-space  addresses  match program order between
              entry to and return from the system  call  (non-running  threads
              are de facto in such a state). This covers threads from all pro=E2=80=90
              cesses running on the system.  This command returns 0.

       The flags argument needs to be 0. For future extensions.

       All memory accesses performed  in  program  order  from  each  targeted
       thread is guaranteed to be ordered with respect to sys_membarrier(). If
       we use the semantic "barrier()" to represent a compiler barrier forcing
       memory  accesses  to  be performed in program order across the barrier,
       and smp_mb() to represent explicit memory barriers forcing full  memory
       ordering  across  the barrier, we have the following ordering table for
       each pair of barrier(), sys_membarrier() and smp_mb():

       The pair ordering is detailed as (O: ordered, X: not ordered):

                              barrier()   smp_mb() sys_membarrier()
              barrier()          X           X            O
              smp_mb()           X           O            O
              sys_membarrier()   O           O            O

RETURN VALUE
       On success, these system calls return zero.  On error, -1 is  returned,
       and errno is set appropriately. For a given command, with flags
       argument set to 0, this system call is guaranteed to always return the
       same value until reboot.

ERRORS
       ENOSYS System call is not implemented.

       EINVAL Invalid arguments.

Linux                             2015-04-15                     MEMBARRIER(2)
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nicholas Miell <nmiell@comcast.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Pranith Kumar <bobby.prani@gmail.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Almost everyone implements dma_set_mask the same way, although some time
that's hidden in ->set_dma_mask methods.

This patch consolidates those into a common implementation that either
calls ->set_dma_mask if present or otherwise uses the default
implementation.  Some architectures used to only call ->set_dma_mask
after the initial checks, and those instance have been fixed to do the
full work.  h8300 implemented dma_set_mask bogusly as a no-ops and has
been fixed.

Unfortunately some architectures overload unrelated semantics like changing
the dma_ops into it so we still need to allow for an architecture override
for now.

[jcmvbkbc@gmail.com: fix xtensa]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Most architectures just call into ->dma_supported, but some also return 1
if the method is not present, or 0 if no dma ops are present (although
that should never happeb). Consolidate this more broad version into
common code.

Also fix h8300 which inorrectly always returned 0, which would have been
a problem if it's dma_set_mask implementation wasn't a similarly buggy
noop.

As a few architectures have much more elaborate implementations, we
still allow for arch overrides.

[jcmvbkbc@gmail.com: fix xtensa]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently there are three valid implementations of dma_mapping_error:

 (1) call ->mapping_error
 (2) check for a hardcoded error code
 (3) always return 0

This patch provides a common implementation that calls ->mapping_error
if present, then checks for DMA_ERROR_CODE if defined or otherwise
returns 0.

[jcmvbkbc@gmail.com: fix xtensa]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Most architectures do not support non-coherent allocations and either
define dma_{alloc,free}_noncoherent to their coherent versions or stub
them out.

Openrisc uses dma_{alloc,free}_attrs to implement them, and only Mips
implements them directly.

This patch moves the Openrisc version to common code, and handles the
DMA_ATTR_NON_CONSISTENT case in the mips dma_map_ops instance.

Note that actual non-coherent allocations require a dma_cache_sync
implementation, so if non-coherent allocations didn't work on
an architecture before this patch they still won't work after it.

[jcmvbkbc@gmail.com: fix xtensa]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since 2009 we have a nice asm-generic header implementing lots of DMA API
functions for architectures using struct dma_map_ops, but unfortunately
it's still missing a lot of APIs that all architectures still have to
duplicate.

This series consolidates the remaining functions, although we still need
arch opt outs for two of them as a few architectures have very
non-standard implementations.

This patch (of 5):

The coherent DMA allocator works the same over all architectures supporting
dma_map operations.

This patch consolidates them and converges the minor differences:

 - the debug_dma helpers are now called from all architectures, including
   those that were previously missing them
 - dma_alloc_from_coherent and dma_release_from_coherent are now always
   called from the generic alloc/free routines instead of the ops
   dma-mapping-common.h always includes dma-coherent.h to get the defintions
   for them, or the stubs if the architecture doesn't support this feature
 - checks for ->alloc / ->free presence are removed.  There is only one
   magic instead of dma_map_ops without them (mic_dma_ops) and that one
   is x86 only anyway.

Besides that only x86 needs special treatment to replace a default devices
if none is passed and tweak the gfp_flags.  An optional arch hook is provided
for that.

[linux@roeck-us.net: fix build]
[jcmvbkbc@gmail.com: fix xtensa]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add the additional "vm_flags_t vm_flags" argument to do_mmap_pgoff(),
rename it to do_mmap(), and re-introduce do_mmap_pgoff() as a simple
wrapper on top of do_mmap().  Perhaps we should update the callers of
do_mmap_pgoff() and kill it later.

This way mpx_mmap() can simply call do_mmap(vm_flags => VM_MPX) and do not
play with vm internals.

After this change mmap_region() has a single user outside of mmap.c,
arch/tile/mm/elf.c:arch_setup_additional_pages().  It would be nice to
change arch/tile/ and unexport mmap_region().

[kirill@shutemov.name: fix build]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NDave Hansen <dave.hansen@linux.intel.com>
Tested-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With two exceptions (drm/qxl and drm/radeon) all vm_operations_struct
structs should be constant.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When loading x86 64bit kernel above 4GiB with patched grub2, got kernel
gunzip error.

| early console in decompress_kernel
| decompress_kernel:
|       input: [0x807f2143b4-0x807ff61aee]
|      output: [0x807cc00000-0x807f3ea29b] 0x027ea29c: output_len
| boot via startup_64
| KASLR using RDTSC...
|  new output: [0x46fe000000-0x470138cfff] 0x0338d000: output_run_size
|  decompress: [0x46fe000000-0x47007ea29b] <=== [0x807f2143b4-0x807ff61aee]
|
| Decompressing Linux... gz...
|
| uncompression error
|
| -- System halted

the new buffer is at 0x46fe000000ULL, decompressor_gzip is using
0xffffffb901ffffff as out_len.  gunzip in lib/zlib_inflate/inflate.c cap
that len to 0x01ffffff and decompress fails later.

We could hit this problem with crashkernel booting that uses kexec loading
kernel above 4GiB.

We have decompress_* support:
    1. inbuf[]/outbuf[] for kernel preboot.
    2. inbuf[]/flush() for initramfs
    3. fill()/flush() for initrd.
This bug only affect kernel preboot path that use outbuf[].

Add __decompress and take real out_buf_len for gunzip instead of guessing
wrong buf size.

Fixes: 1431574a (lib/decompressors: fix "no limit" output buffer length)
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Jon Medhurst <tixy@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are two kexec load syscalls, kexec_load another and kexec_file_load.
 kexec_file_load has been splited as kernel/kexec_file.c.  In this patch I
split kexec_load syscall code to kernel/kexec.c.

And add a new kconfig option KEXEC_CORE, so we can disable kexec_load and
use kexec_file_load only, or vice verse.

The original requirement is from Ted Ts'o, he want kexec kernel signature
being checked with CONFIG_KEXEC_VERIFY_SIG enabled.  But kexec-tools use
kexec_load syscall can bypass the checking.

Vivek Goyal proposed to create a common kconfig option so user can compile
in only one syscall for loading kexec kernel.  KEXEC/KEXEC_FILE selects
KEXEC_CORE so that old config files still work.

Because there's general code need CONFIG_KEXEC_CORE, so I updated all the
architecture Kconfig with a new option KEXEC_CORE, and let KEXEC selects
KEXEC_CORE in arch Kconfig.  Also updated general kernel code with to
kexec_load syscall.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NDave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Petr Tesarik <ptesarik@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The linux/audit.h header uses EM_MICROBLAZE in order to define
AUDIT_ARCH_MICROBLAZE, but it's only available in the microblaze
asm headers.  Move it to the common elf-em.h header so that the
define can be used on non-microblaze systems.  Otherwise we get
build errors that EM_MICROBLAZE isn't defined when we try to use
the AUDIT_ARCH_MICROBLAZE symbol.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

PBIAS regulator is required for MMC module in OMAP2, OMAP3, OMAP4,
OMAP5 and DRA7 SoCs. Enable it here.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NKevin Hilman <khilman@linaro.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.

Cc: Tim Bird <tim.bird@sonymobile.com>
Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.

Cc: Mathieu Olivari <mathieu@codeaurora.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Use stdout-path so that we don't have to put the console on the
kernel command line.

Cc: Mike Rapoport <mike.rapoport@gmail.com>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Add a label to the serial nodes that are being used for the
console.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

This reverts commit f3f601c1.

UAPI headers cannot use "uapi/" in their paths by design -- when they're
installed, they do not have the uapi/ prefix.  Otherwise doing so breaks
userland badly.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NRichard Kuo <rkuo@codeaurora.org>

Migrate hexagon driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

We weren't doing anything in the ->set_mode() callback. So, this patch
doesn't provide any set-state callbacks.

Cc: linux-hexagon@vger.kernel.org
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRichard Kuo <rkuo@codeaurora.org>

alloc_pages_exact_node() was introduced in commit 6484eb3e ("page
allocator: do not check NUMA node ID when the caller knows the node is
valid") as an optimized variant of alloc_pages_node(), that doesn't
fallback to current node for nid == NUMA_NO_NODE.  Unfortunately the
name of the function can easily suggest that the allocation is
restricted to the given node and fails otherwise.  In truth, the node is
only preferred, unless __GFP_THISNODE is passed among the gfp flags.

The misleading name has lead to mistakes in the past, see for example
commits 5265047a ("mm, thp: really limit transparent hugepage
allocation to local node") and b360edb4 ("mm, mempolicy:
migrate_to_node should only migrate to node").

Another issue with the name is that there's a family of
alloc_pages_exact*() functions where 'exact' means exact size (instead
of page order), which leads to more confusion.

To prevent further mistakes, this patch effectively renames
alloc_pages_exact_node() to __alloc_pages_node() to better convey that
it's an optimized variant of alloc_pages_node() not intended for general
usage.  Both functions get described in comments.

It has been also considered to really provide a convenience function for
allocations restricted to a node, but the major opinion seems to be that
__GFP_THISNODE already provides that functionality and we shouldn't
duplicate the API needlessly.  The number of users would be small
anyway.

Existing callers of alloc_pages_exact_node() are simply converted to
call __alloc_pages_node(), with the exception of sba_alloc_coherent()
which open-codes the check for NUMA_NO_NODE, so it is converted to use
alloc_pages_node() instead.  This means it no longer performs some
VM_BUG_ON checks, and since the current check for nid in
alloc_pages_node() uses a 'nid < 0' comparison (which includes
NUMA_NO_NODE), it may hide wrong values which would be previously
exposed.

Both differences will be rectified by the next patch.

To sum up, this patch makes no functional changes, except temporarily
hiding potentially buggy callers.  Restricting the checks in
alloc_pages_node() is left for the next patch which can in turn expose
more existing buggy callers.
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NRobin Holt <robinmholt@gmail.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Cliff Whickman <cpw@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The early_ioremap library now has a generic copy_from_early_mem()
function.  Use the generic copy function for x86 relocate_initrd().

[akpm@linux-foundation.org: remove MAX_MAP_CHUNK define, per Yinghai Lu]
Signed-off-by: NMark Salter <msalter@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The use of mem= could leave part or all of the initrd outside of the
kernel linear map.  This will lead to an error when unpacking the initrd
and a probable failure to boot.  This patch catches that situation and
relocates the initrd to be fully within the linear map.
Signed-off-by: NMark Salter <msalter@redhat.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When parsing SRAT, all memory ranges are added into numa_meminfo.  In
numa_init(), before entering numa_cleanup_meminfo(), all possible memory
ranges are in numa_meminfo.  And numa_cleanup_meminfo() removes all
ranges over max_pfn or empty.

But, this only works if the nodes are continuous.  Let's have a look at
the following example:

We have an SRAT like this:
SRAT: Node 0 PXM 0 [mem 0x00000000-0x5fffffff]
SRAT: Node 0 PXM 0 [mem 0x100000000-0x1ffffffffff]
SRAT: Node 1 PXM 1 [mem 0x20000000000-0x3ffffffffff]
SRAT: Node 4 PXM 2 [mem 0x40000000000-0x5ffffffffff] hotplug
SRAT: Node 5 PXM 3 [mem 0x60000000000-0x7ffffffffff] hotplug
SRAT: Node 2 PXM 4 [mem 0x80000000000-0x9ffffffffff] hotplug
SRAT: Node 3 PXM 5 [mem 0xa0000000000-0xbffffffffff] hotplug
SRAT: Node 6 PXM 6 [mem 0xc0000000000-0xdffffffffff] hotplug
SRAT: Node 7 PXM 7 [mem 0xe0000000000-0xfffffffffff] hotplug

On boot, only node 0,1,2,3 exist.

And the numa_meminfo will look like this:
numa_meminfo.nr_blks = 9
1. on node 0: [0, 60000000]
2. on node 0: [100000000, 20000000000]
3. on node 1: [20000000000, 40000000000]
4. on node 4: [40000000000, 60000000000]
5. on node 5: [60000000000, 80000000000]
6. on node 2: [80000000000, a0000000000]
7. on node 3: [a0000000000, a0800000000]
8. on node 6: [c0000000000, a0800000000]
9. on node 7: [e0000000000, a0800000000]

And numa_cleanup_meminfo() will merge 1 and 2, and remove 8,9 because the
end address is over max_pfn, which is a0800000000.  But 4 and 5 are not
removed because their end addresses are less then max_pfn.  But in fact,
node 4 and 5 don't exist.

In a word, numa_cleanup_meminfo() is not able to handle holes between nodes.

Since memory ranges in node 4 and 5 are in numa_meminfo, in
numa_register_memblks(), node 4 and 5 will be mistakenly set to online.

If you run lscpu, it will show:
NUMA node0 CPU(s):     0-14,128-142
NUMA node1 CPU(s):     15-29,143-157
NUMA node2 CPU(s):
NUMA node3 CPU(s):
NUMA node4 CPU(s):     62-76,190-204
NUMA node5 CPU(s):     78-92,206-220

In this patch, we use memblock_overlaps_region() to check if ranges in
numa_meminfo overlap with ranges in memory_block.  Since memory_block
contains all available memory at boot time, if they overlap, it means the
ranges exist.  If not, then remove them from numa_meminfo.

After this patch, lscpu will show:
NUMA node0 CPU(s):     0-14,128-142
NUMA node1 CPU(s):     15-29,143-157
NUMA node4 CPU(s):     62-76,190-204
NUMA node5 CPU(s):     78-92,206-220
Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

"memcg: export struct mem_cgroup" will add includes into
linux/memcontrol.h which lead to further header dependency issues as
reported by Guenter Roeck:

  In file included from include/linux/highmem.h:7:0,
                   from include/linux/bio.h:23,
                   from include/linux/writeback.h:192,
                   from include/linux/memcontrol.h:30,
                   from include/linux/swap.h:8,
                   from ./arch/sparc/include/asm/pgtable_32.h:17,
                   from ./arch/sparc/include/asm/pgtable.h:6,
                   from arch/sparc/kernel/traps_32.c:23:
  include/linux/mm.h: In function 'is_vmalloc_addr':
  include/linux/mm.h:371:17: error: 'VMALLOC_START' undeclared (first use in this function)
  include/linux/mm.h:371:17: note: each undeclared identifier is reported only once for each function it appears in
  include/linux/mm.h:371:41: error: 'VMALLOC_END' undeclared (first use in this function)
  include/linux/mm.h: In function 'maybe_mkwrite':
  include/linux/mm.h:556:3: error: implicit declaration of function 'pte_mkwrite'

The issue is that pgtable_32.h depends on swap.h to get swap_entry_t but
that goes all the way down to linux/mm.h which wants to have VMALLOC_*
which is defined later in pgtable_32.h, though.

swap_entry_t is defined in include/mm_types.h so it should be sufficient
to include this header without more dependencies.
Signed-off-by: NMichal Hocko <mhocko@suse.com>
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The privcmd code is mixing the usage of GFN and MFN within the same
functions which make the code difficult to understand when you only work
with auto-translated guests.

The privcmd driver is only dealing with GFN so replace all the mention
of MFN into GFN.

The ioctl structure used to map foreign change has been left unchanged
given that the userspace is using it. Nonetheless, add a comment to
explain the expected value within the "mfn" field.
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
is meant, I suspect this is because the first support for Xen was for
PV. This resulted in some misimplementation of helpers on ARM and
confused developers about the expected behavior.

For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.

For clarity and avoid new confusion, replace any reference to mfn with
gfn in any helpers used by PV drivers. The x86 code will still keep some
reference of pfn_to_mfn which may be used by all kind of guests
No changes as been made in the hypercall field, even
though they may be invalid, in order to keep the same as the defintion
in xen repo.

Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a
name to close to the KVM function gfn_to_page.

Take also the opportunity to simplify simple construction such
as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up
will come in follow-up patches.

[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cbSigned-off-by: NJulien Grall <julien.grall@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

After the commit introducing convertion between DMA and guest addresses,
all the callers of pfn_to_mfn are expecting to get a GFN (Guest Frame
Number). On ARM, all the guests are auto-translated so the GFN is equal
to the Linux PFN (Pseudo-physical Frame Number).

The current implementation may return an MFN if the caller is passing a
PFN associated to a mapped foreign grant. In pratice, I haven't seen
the problem on running guest but we should fix it for the sake of
correctness.

Correct the implementation by always returning the pfn passed in parameter.

A follow-up patch will take care to rename pfn_to_mfn to a suitable
name.
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

The swiotlb is required when programming a DMA address on ARM when a
device is not protected by an IOMMU.

In this case, the DMA address should always be equal to the machine address.
For DOM0 memory, Xen ensure it by have an identity mapping between the
guest address and host address. However, when mapping a foreign grant
reference, the 1:1 model doesn't work.

For ARM guest, most of the callers of pfn_to_mfn expects to get a GFN
(Guest Frame Number), i.e a PFN (Page Frame Number) from the Linux point
of view given that all ARM guest are auto-translated.

Even though the name pfn_to_mfn is misleading, we need to ensure that
those caller get a GFN and not by mistake a MFN. In pratical, I haven't
seen error related to this but we should fix it for the sake of
correctness.

In order to fix the implementation of pfn_to_mfn on ARM in a follow-up
patch, we have to introduce new helpers to return the DMA from a PFN and
the invert.

On x86, the new helpers will be an alias of pfn_to_mfn and mfn_to_pfn.

The helpers will be used in swiotlb and xen_biovec_phys_mergeable.

This is necessary in the latter because we have to ensure that the
biovec code will not try to merge a biovec using foreign page and
another using Linux memory.

Lastly, the helper mfn_to_local_pfn has been renamed to bfn_to_local_pfn
given that the only usage was in swiotlb.
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Signed-off-by: NHelge Deller <deller@gmx.de>