This is my example conversion of a few existing mmap users.  The mtdchar
case is actually disabled right now (and stays disabled), but I did it
because it showed up on my "git grep", and I was familiar with the code
due to fixing an overflow problem in the code in commit 9c603e53
("mtdchar: fix offset overflow detection").
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is my example conversion of a few existing mmap users.  The HPET
case is simple, widely available, and easy to test (Clemens Ladisch sent
a trivial test-program for it).
Test-program-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull input fixes from Dmitry Torokhov:
 "Two more small fixups to the wacom driver"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: wacom - fix "can not retrieve extra class descriptor" for DTH2242
  Input: wacom - DTH2242 Grip Pen id was off by one bit

Pull fuse build fix from Miklos Szeredi:
 "This fixes android builds.  The patch appears large, but is just
  search & replace."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix type definitions in uapi header

Same as Cintiq 24HDT, DTH2242 has two interfaces sharing one configuration.
This patch ignores the second interface.
Signed-off-by: NPing Cheng <pingc@wacom.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

Signed-off-by: NPing Cheng <pingc@wacom.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

Pull user-namespace fixes from Andy Lutomirski.

* 'userns-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux:
  userns: Changing any namespace id mappings should require privileges
  userns: Check uid_map's opener's fsuid, not the current fsuid
  userns: Don't let unprivileged users trick privileged users into setting the id_map

Pull x86 platform driver revert from Matthew Garrett:
 "It turns out that one of the hp-wmi patches this cycle breaks some
  other HP laptops.  I think we have a good idea how to work on it for
  3.10, but it's safer to just revert it for now."

* 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86:
  Revert "hp-wmi: Add support for SMBus hotkeys"

This reverts commit fabf85e3 which breaks
hotkey support on some other HP laptops. We'll try doing this differently
in 3.10.
Signed-off-by: NMatthew Garrett <matthew.garrett@nebula.com>

This reverts commit 3a366e61.

Wanlong Gao reports that it causes a kernel panic on his machine several
minutes after boot. Reverting it removes the panic.

Jens says:
 "It's not quite clear why that is yet, so I think we should just revert
  the commit for 3.9 final (which I'm assuming is pretty close).

  The wifi is crap at the LSF hotel, so sending this email instead of
  queueing up a revert and pull request."
Reported-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Requested-by: NJens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix a double locking bug caused when debug.kprobe-optimization=0.
While the proc_kprobes_optimization_handler locks kprobe_mutex,
wait_for_kprobe_optimizer locks it again and that causes a double lock.
To fix the bug, this introduces different mutex for protecting
sysctl parameter and locks it in proc_kprobes_optimization_handler.
Of course, since we need to lock kprobe_mutex when touching kprobes
resources, that is done in *optimize_all_kprobes().

This bug was introduced by commit ad72b3be ("kprobes: fix
wait_for_kprobe_optimizer()")
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The BUG_ON() directive is triggered probably due to a latency
modification following inclusion of commit c10d7367 ("softirq:
reduce latencies").  This condition has not been met before 3.9-rc1 and
doesn't trigger without this patch.

We now make sure that DMA channel is idle before calling
atc_complete_all() which makes the BUG_ON() "protection" useless.
Signed-off-by: NLudovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull idle patches from Len Brown:
 "A pair of small patches for 3.9-rc7.

  This CPU-id should have been included in the ones that we updated
  earlier in 3.9.  This pair of patches will allow this flavor of
  Haswell to behave like the other flavors."

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
  tools/power turbostat: additional Haswell CPU-id
  intel_idle: additional Haswell CPU-id

Pull misc fixes from Andrew Morton:
 "Ten fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel/signal.c: stop info leak via the tkill and the tgkill syscalls
  mm/vmscan: fix error return in kswapd_run()
  hfsplus: fix potential overflow in hfsplus_file_truncate()
  avr32: fix build error in atstk1006_defconfig
  hugetlbfs: add swap entry check in follow_hugetlb_page()
  fs/binfmt_elf.c: fix hugetlb memory check in vma_dump_size()
  hugetlbfs: stop setting VM_DONTDUMP in initializing vma(VM_HUGETLB)
  checkpatch: fix stringification macro defect
  drivers/video/mmp/core.c: fix use-after-free bug
  thinkpad-acpi: kill hotkey_thread_mutex

This fixes a kernel memory contents leak via the tkill and tgkill syscalls
for compat processes.

This is visible in the siginfo_t->_sifields._rt.si_sigval.sival_ptr field
when handling signals delivered from tkill.

The place of the infoleak:

int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
{
        ...
        put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
        ...
}
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
Reviewed-by: NPaX Team <pageexec@freemail.hu>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the error return value in kswapd_run().  The bug was introduced by
commit d5dc0ad9 ("mm/vmscan: fix error number for failed kthread").
Signed-off-by: NXishi Qiu <qiuxishi@huawei.com>
Reviewed-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change a u32 to loff_t hfsplus_file_truncate().
Signed-off-by: NVyacheslav Dubeyko <slava@dubeyko.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fixed the following compile error when use avr32 atstk1006_defconfig:

  drivers/mtd/nand/atmel_nand.c: In function 'pmecc_err_location':
  drivers/mtd/nand/atmel_nand.c:639: error: implicit declaration of function 'writel_relaxed'

which was introduced by commit 1c7b874d ("mtd: at91: atmel_nand: add
Programmable Multibit ECC controller support").  The PMECC for nand
flash code uses writel_relaxed().  But in avr32, there is no macro
"writel_relaxed" defined.

This patch add writex_relaxed macro definitions.
Signed-off-by: NJosh Wu <josh.wu@atmel.com>
Acked-by: NHavard Skinnemoen <havard@skinnemoen.net>
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With applying the previous patch "hugetlbfs: stop setting VM_DONTDUMP in
initializing vma(VM_HUGETLB)" to reenable hugepage coredump, if a memory
error happens on a hugepage and the affected processes try to access the
error hugepage, we hit VM_BUG_ON(atomic_read(&page->_count) <= 0) in
get_page().

The reason for this bug is that coredump-related code doesn't recognise
"hugepage hwpoison entry" with which a pmd entry is replaced when a memory
error occurs on a hugepage.

In other words, physical address information is stored in different bit
layout between hugepage hwpoison entry and pmd entry, so
follow_hugetlb_page() which is called in get_dump_page() returns a wrong
page from a given address.

The expected behavior is like this:

  absent   is_swap_pte   FOLL_DUMP   Expected behavior
  -------------------------------------------------------------------
   true     false         false       hugetlb_fault
   false    true          false       hugetlb_fault
   false    false         false       return page
   true     false         true        skip page (to avoid allocation)
   false    true          true        hugetlb_fault
   false    false         true        return page

With this patch, we can call hugetlb_fault() and take proper actions (we
wait for migration entries, fail with VM_FAULT_HWPOISON_LARGE for
hwpoisoned entries,) and as the result we can dump all hugepages except
for hwpoisoned ones.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[2.6.34+?]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/proc.txt says about coredump_filter bitmask,

  Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only
  effected by bit 5-6.

However current code can go into the subsequent flag checks of bit 0-4
for vma(VM_HUGETLB). So this patch inserts 'return' and makes it work
as written in the document.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[3.7+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently we fail to include any data on hugepages into coredump,
because VM_DONTDUMP is set on hugetlbfs's vma.  This behavior was
recently introduced by commit 314e51b9 ("mm: kill vma flag
VM_RESERVED and mm->reserved_vm counter").

This looks to me a serious regression, so let's fix it.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NRik van Riel <riel@redhat.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[3.7+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix checkpatch misreporting defect with stringification macros

ERROR: Macros with complex values should be enclosed in parenthesis
  #27: FILE: arch/arm/include/asm/kgdb.h:41:
  +#define ___to_string(X) #X
Signed-off-by: NJoe Perches <joe@perches.com>
Reported-by: NVincent Stehlé <v-stehle@ti.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Found with coccinelle.
Signed-off-by: NAndrei Epure <epure.andrei@gmail.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex.

We can simply kill this mutex, hotkey_poll_stop_sync() does not need to
serialize with hotkey_kthread().  When kthread_stop() returns the thread
is already dead, it called do_exit()->complete_vfork_done().
Reported-by: NArtem Savkov <artem.savkov@gmail.com>
Reported-by: NMaciej Rutecki <maciej.rutecki@gmail.com>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Matthew Garrett <matthew.garrett@nebula.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Reviewed-by: NMandeep Singh Baines <msb@chromium.org>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull Ceph fix from Sage Weil:
 "It's a simple fix for a hard to hit race, but low-risk and clearly
  correct"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  rbd: do a safe list traversal in rbd_img_request_submit()

In the very unlikely event where a guest would be foolish enough to
*read* from a write-only cache maintainance register, we end up
with preemption disabled, due to a misplaced get_cpu().

Just move the "is_write" test outside of the critical section.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NChristoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's possible that the reference to the object request dropped
inside the loop in rbd_img_request_submit() will be the last
one, in which case the content of the object pointer can't be
trusted.

Use a safe form of the object request list traversal to avoid
problems.

This resolves:
    http://tracker.ceph.com/issues/4705Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Pull networking fixes from David Miller:

 1) Fix erroneous netfilter drop of SIP packets generated by some Cisco
    phones, from Patrick McHardy.

 2) Fix netfilter IPSET refcounting in list_set_add(), from Jozsef
    Kadlecsik.

 3) Fix TCP syncookies route lookup key, we don't use the same values we
    would use for the usual SYN receive processing, from Dmitry Popov.

 4) Fix NULL deref in bond_slave_netdev_event(), from Nikolay
    Aleksandrov.

 5) When bonding enslave fails, we can forget to clear the IFF_BONDING
    bit, fix also from Nikolay Aleksandrov.

 6) skb->csum_start is 16-bits, which is almost always just fine.  But
    if we reallocate the headroom of an SKB this can push the
    skb->csum_start value outside of it's valid range.  This can easily
    happen when collapsing multiple SKBs from the retransmit queue
    together.

    Fix from Thomas Graf.

 7) Fix NULL deref in be2net driver due to missing check of
    __vlan_put_tag() return value, from Ivan Vecera.

 8) tun_set_iff() returns zero instead of error code on failure, fix
    from Wei Yongjun.

 9) Like GARP, 802 MRP needs to hold the app->lock when adding MAD
    events and queueing PDUs.  Fix from David Ward.

10) Build fix, MVMDIO needs PHYLIB, from Thomas Petazzoni..

11) Fix mac80211 static with ipv6 modular build, from Cong Wang.

12) If userland specifies a path cost explicitly, do not override it
    when the carrier state changes.  From Stephen Hemminger.

13) mvnets calculates the TX queue to use incorrectly resulting in
    garbage pointer derefs and crashes, fix from Willy Tarreau.

14) cdc_mbim does erroneous sizeof(ETH_HLEN).  Fix from Bjorn Mork.

15) IP fragmentation can leak a refcount-less route out from an RCU
    protected section.  This results in crashes and all sorts of hard to
    diagnose behavior.  Fix from Eric Dumazet.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (24 commits)
  qlcnic: fix beaconing test for 82xx adapter
  net: drop dst before queueing fragments
  net: fec: fix regression in link change accounting
  net: cdc_mbim: remove bogus sizeof()
  drivers: net: ethernet: cpsw: get slave VLAN id from slave node instead of cpsw node
  net: mvneta: fix improper tx queue usage in mvneta_tx()
  esp4: fix error return code in esp_output()
  bridge: make user modified path cost sticky
  ipv6: statically link register_inet6addr_notifier()
  net: mvmdio: add select PHYLIB
  net/802/mrp: fix possible race condition when calling mrp_pdu_queue()
  tuntap: fix error return code in tun_set_iff()
  be2net: take care of __vlan_put_tag return value
  can: sja1000: fix handling on dt properties on little endian systems
  can: mcp251x: add missing IRQF_ONESHOT to request_threaded_irq
  netfilter: nf_nat: fix race when unloading protocol modules
  tcp: Reallocate headroom if it would overflow csum_start
  stmmac: prevent interrupt loop with MMC RX IPC Counter
  bonding: IFF_BONDING is not stripped on enslave failure
  bonding: fix netdev event NULL pointer dereference
  ...

Commit b4cbb197 ("vm: add vm_iomap_memory() helper function") added
a helper function wrapper around io_remap_pfn_range(), and every other
architecture defined it in <asm/pgtable.h>.

The s390 choice of <asm/io.h> may make sense, but is not very convenient
for this case, and gratuitous differences like that cause unexpected errors like this:

   mm/memory.c: In function 'vm_iomap_memory':
   mm/memory.c:2439:2: error: implicit declaration of function 'io_remap_pfn_range' [-Werror=implicit-function-declaration]

Glory be the kbuild test robot who noticed this, bisected it, and
reported it to the guilty parties (ie me).

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 7e98d530 (Synchronize fuse header with
one used in library) added #ifdef __linux__ around defines if it is not set.
The kernel build is self-contained and can be built on non-Linux toolchains.
After the mentioned commit builds on non-Linux toolchains will try to include
stdint.h and fail due to -nostdinc, and then fail with a bunch of undefined type
errors.

Fix by checking for __KERNEL__ instead of __linux__ and using the standard int
types instead of the linux specific ones.
Reported-by: NArve Hjønnevåg <arve@android.com>
Reported-by: NColin Cross <ccross@android.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

o Commit 319ecf12
  ("qlcnic: 83xx sysfs routines") introduced regression
  for beaconing test while refactoring 82xx code. This patch is to
  revert code to fix beaconing test for 82xx adapter.
Signed-off-by: NHimanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: NShahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 4a94445c (net: Use ip_route_input_noref() in input path)
added a bug in IP defragmentation handling, as non refcounted
dst could escape an RCU protected section.

Commit 64f3b9e2 (net: ip_expire() must revalidate route) fixed
the case of timeouts, but not the general problem.

Tom Parkin noticed crashes in UDP stack and provided a patch,
but further analysis permitted us to pinpoint the root cause.

Before queueing a packet into a frag list, we must drop its dst,
as this dst has limited lifetime (RCU protected)

When/if a packet is finally reassembled, we use the dst of the very
last skb, still protected by RCU and valid, as the dst of the
reassembled packet.

Use same logic in IPv6, as there is no need to hold dst references.
Reported-by: NTom Parkin <tparkin@katalix.com>
Tested-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull ARM fix from Russell King:
 "A build fix for an incomplete change to the ARM cpu suspend code"

* branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: Do 15e0d9e3 (ARM: pm: let platforms select cpu_suspend support) properly

Pull kvm fixes from Marcelo Tosatti:
 "PPC and ARM KVM fixes"

* git://git.kernel.org/pub/scm/virt/kvm/kvm:
  ARM: KVM: fix L_PTE_S2_RDWR to actually be Read/Write
  ARM: KVM: fix KVM_CAP_ARM_SET_DEVICE_ADDR reporting
  kvm/ppc/e500: eliminate tlb_refs
  kvm/ppc/e500: g2h_tlb1_map: clear old bit before setting new bit
  kvm/ppc/e500: h2g_tlb1_rmap: esel 0 is valid
  kvm/powerpc/e500mc: fix tlb invalidation on cpu migration

Pull powerpc fixes from Stephen Rothwell:
 "Three regresions in the PowerPC code.  One from v3.7 the others from
  this merge window."

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sfr/next-fixes:
  powerpc: add a missing label in resume_kernel
  powerpc: Fix audit crash due to save/restore PPR changes
  powerpc: fix compiling CONFIG_PPC_TRANSACTIONAL_MEM when CONFIG_ALTIVEC=n

Pull kbuild fix from Michal Marek:
 "Fix for a missing dependency when generating scripts/mod/devicetable-offsets.h.
  This dependency got introduced in v3.9-rc1."

* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  kbuild: generate generic headers before recursing into scripts

Pull input fixes from Dmitry Torokhov:
 "Two small fixups to the Wacom driver"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: wacom - correct reported resolution for Intuos4 Wireless
  Input: wacom - fix "can not retrieve extra class descriptor" for 24HDT

* 'kvm-arm-fixes-3.9' of git://github.com/columbia/linux-kvm-arm:
  ARM: KVM: fix L_PTE_S2_RDWR to actually be Read/Write
  ARM: KVM: fix KVM_CAP_ARM_SET_DEVICE_ADDR reporting
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Various drivers end up replicating the code to mmap() their memory
buffers into user space, and our core memory remapping function may be
very flexible but it is unnecessarily complicated for the common cases
to use.

Our internal VM uses pfn's ("page frame numbers") which simplifies
things for the VM, and allows us to pass physical addresses around in a
denser and more efficient format than passing a "phys_addr_t" around,
and having to shift it up and down by the page size.  But it just means
that drivers end up doing that shifting instead at the interface level.

It also means that drivers end up mucking around with internal VM things
like the vma details (vm_pgoff, vm_start/end) way more than they really
need to.

So this just exports a function to map a certain physical memory range
into user space (using a phys_addr_t based interface that is much more
natural for a driver) and hides all the complexity from the driver.
Some drivers will still end up tweaking the vm_page_prot details for
things like prefetching or cacheability etc, but that's actually
relevant to the driver, rather than caring about what the page offset of
the mapping is into the particular IO memory region.
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Looks like our L_PTE_S2_RDWR definition is slightly wrong,
and is actually write only (see ARM ARM Table B3-9, Stage 2 control
of access permissions). Didn't make a difference for normal pages,
as we OR the flags together, but I'm still wondering how it worked
for Stage-2 mapped devices, such as the GIC.

Brown paper bag time, again.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NChristoffer Dall <cdall@cs.columbia.edu>