Pagefault handling has a BUG_ON path that panics the system. Convert it to
a warning instead. There is no need to bring down the system for this kind
of failure.

The following was hit while running:
    perf sched record -g -- make -j 16

[3609412.782801] kernel BUG at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:416!
[3609412.782833]               \|/ ____ \|/
[3609412.782833]               "@'/ .. \`@"
[3609412.782833]               /_| \__/ |_\
[3609412.782833]                  \__U_/
[3609412.782870] cat(4516): Kernel bad sw trap 5 [#1]
[3609412.782889] CPU: 0 PID: 4516 Comm: cat Tainted: G            E   4.1.0-rc8+ #6
[3609412.782909] task: fff8000126e31f80 ti: fff8000110d90000 task.ti: fff8000110d90000
[3609412.782931] TSTATE: 0000004411001603 TPC: 000000000096b164 TNPC: 000000000096b168 Y: 0000004e    Tainted: G            E
[3609412.782964] TPC: <do_sparc64_fault+0x5e4/0x6a0>
[3609412.782979] g0: 000000000096abe0 g1: 0000000000d314c4 g2: 0000000000000000 g3: 0000000000000001
[3609412.783009] g4: fff8000126e31f80 g5: fff80001302d2000 g6: fff8000110d90000 g7: 00000000000000ff
[3609412.783045] o0: 0000000000aff6a8 o1: 00000000000001a0 o2: 0000000000000001 o3: 0000000000000054
[3609412.783080] o4: fff8000100026820 o5: 0000000000000001 sp: fff8000110d935f1 ret_pc: 000000000096b15c
[3609412.783117] RPC: <do_sparc64_fault+0x5dc/0x6a0>
[3609412.783137] l0: 000007feff996000 l1: 0000000000030001 l2: 0000000000000004 l3: fff8000127bd0120
[3609412.783174] l4: 0000000000000054 l5: fff8000127bd0188 l6: 0000000000000000 l7: fff8000110d9dba8
[3609412.783210] i0: fff8000110d93f60 i1: fff8000110ca5530 i2: 000000000000003f i3: 0000000000000054
[3609412.783244] i4: fff800010000081a i5: fff8000100000398 i6: fff8000110d936a1 i7: 0000000000407c6c
[3609412.783286] I7: <sparc64_realfault_common+0x10/0x20>
[3609412.783308] Call Trace:
[3609412.783329]  [0000000000407c6c] sparc64_realfault_common+0x10/0x20
[3609412.783353] Disabling lock debugging due to kernel taint
[3609412.783379] Caller[0000000000407c6c]: sparc64_realfault_common+0x10/0x20
[3609412.783449] Caller[fff80001002283e4]: 0xfff80001002283e4
[3609412.783471] Instruction DUMP: 921021a0  7feaff91  901222a8 <91d02005> 82086100  02f87f7b  808a2873  81cfe008  01000000
[3609412.783542] Kernel panic - not syncing: Fatal exception
[3609412.784605] Press Stop-A (L1-A) to return to the boot prom
[3609412.784615] ---[ end Kernel panic - not syncing: Fatal exception

With this patch rather than a panic I occasionally get something like this:
    perf sched record -g -m 1024  -- make -j N

where N is based on number of cpus (128 to 1024 for a T7-4 and 8 for an 8 cpu
VM on a T5-2).

WARNING: CPU: 211 PID: 52565 at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:417 do_sparc64_fault+0x340/0x70c()
address (7feffcd6000) != regs->tpc (fff80001004873c0)
Modules linked in: ipt_REJECT nf_reject_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_reject_ipv6 xt_tcpudp nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables x_tables ipv6 cdc_ether usbnet mii ixgbe mdio igb i2c_algo_bit i2c_core ptp crc32c_sparc64 camellia_sparc64 des_sparc64 des_generic md5_sparc64 sha512_sparc64 sha1_sparc64 uio_pdrv_genirq uio usb_storage mpt3sas scsi_transport_sas raid_class aes_sparc64 sunvnet sunvdc sha256_sparc64(E) sha256_generic(E)
CPU: 211 PID: 52565 Comm: ld Tainted: G        W   E   4.1.0-rc8+ #19
Call Trace:
 [000000000045ce30] warn_slowpath_common+0x7c/0xa0
 [000000000045ceec] warn_slowpath_fmt+0x30/0x40
 [000000000098ad64] do_sparc64_fault+0x340/0x70c
 [0000000000407c2c] sparc64_realfault_common+0x10/0x20
---[ end trace 62ee02065a01a049 ]---
ld[52565]: segfault at fff80001004873c0 ip fff80001004873c0 (rpc fff8000100158868) sp 000007feffcd70e1 error 30002 in libc-2.12.so[fff8000100410000+184000]

The segfault is horrible, but better than a system panic.

An 8-cpu VM on a T5-2 also showed the above traces from time to time,
so it is a general problem and not specific to the T7 or baremetal.
Signed-off-by: NDavid Ahern <david.ahern@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce faulthandler_disabled() and use it to check for irq context and
disabled pagefaults (via pagefault_disable()) in the pagefault handlers.

Please note that we keep the in_atomic() checks in place - to detect
whether in irq context (in which case preemption is always properly
disabled).

In contrast, preempt_disable() should never be used to disable pagefaults.
With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt
counter, and therefore the result of in_atomic() differs.
We validate that condition by using might_fault() checks when calling
might_sleep().

Therefore, add a comment to faulthandler_disabled(), describing why this
is needed.

faulthandler_disabled() and pagefault_disable() are defined in
linux/uaccess.h, so let's properly add that include to all relevant files.

This patch is based on a patch from Thomas Gleixner.
Reviewed-and-tested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.
Reported-and-tested-by: NTakashi Iwai <tiwai@suse.de>
Tested-by: NJan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We've witnessed a few TLB events causing the machine to power off because
of prom_halt. In one case it was some nfs related area during rmmod. Another
was an mmapper of /dev/mem. A more recent one is an ITLB issue with
a bad pagesize which could be a hardware bug. Bugs happen but we should
attempt to not power off the machine and/or hang it when possible.

This is a DTLB error from an mmapper of /dev/mem:
[root@sparcie ~]# SUN4V-DTLB: Error at TPC[fffff80100903e6c], tl 1
SUN4V-DTLB: TPC<0xfffff80100903e6c>
SUN4V-DTLB: O7[fffff801081979d0]
SUN4V-DTLB: O7<0xfffff801081979d0>
SUN4V-DTLB: vaddr[fffff80100000000] ctx[1250] pte[98000000000f0610] error[2]
.

This is recent mainline for ITLB:
[ 3708.179864] SUN4V-ITLB: TPC<0xfffffc010071cefc>
[ 3708.188866] SUN4V-ITLB: O7[fffffc010071cee8]
[ 3708.197377] SUN4V-ITLB: O7<0xfffffc010071cee8>
[ 3708.206539] SUN4V-ITLB: vaddr[e0003] ctx[1a3c] pte[2900000dcc800eeb] error[4]
.

Normally sun4v_itlb_error_report() and sun4v_dtlb_error_report() would call
prom_halt() and drop us to OF command prompt "ok". This isn't the case for
LDOMs and the machine powers off.

For the HV reported error of HV_ENORADDR for HV HV_MMU_MAP_ADDR_TRAP we cause
a SIGBUS error by qualifying it within do_sparc64_fault() for fault code mask
of FAULT_CODE_BAD_RA. This is done when trap level (%tl) is less or equal
one("1"). Otherwise, for %tl > 1,  we proceed eventually to die_if_kernel().

The logic of this patch was partially inspired by David Miller's feedback.

Power off of large sparc64 machines is painful. Plus die_if_kernel provides
more context. A reset sequence isn't a brief period on large sparc64 but
better than power-off/power-on sequence.

Cc: sparclinux@vger.kernel.org
Signed-off-by: NBob Picco <bob.picco@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix following warnings:
kernel/sys_sparc_64.c:643:17: warning: symbol 'sys_kern_features' was not declared. Should it be static?
kernel/unaligned_64.c:297:17: warning: symbol 'kernel_unaligned_trap' was not declared. Should it be static?
kernel/unaligned_64.c:387:5: warning: symbol 'handle_popc' was not declared. Should it be static?
kernel/unaligned_64.c:428:5: warning: symbol 'handle_ldf_stq' was not declared. Should it be static?
kernel/unaligned_64.c:553:6: warning: symbol 'handle_ld_nf' was not declared. Should it be static?
kernel/unaligned_64.c:579:6: warning: symbol 'handle_lddfmna' was not declared. Should it be static?
kernel/unaligned_64.c:643:6: warning: symbol 'handle_stdfmna' was not declared. Should it be static?

Functions that are only used in kernel/ - add prototypes in kernel.h
Functions used outside kernel/ - add prototype in asm/setup.h
Removed local prototypes

One of the local prototypes had wrong signature (return void - not int).
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This was found using Dave Jone's trinity tool.

When a user process which is 32-bit performs a load or a store, the
cpu chops off the top 32-bits of the effective address before
translating it.

This is because we run 32-bit tasks with the PSTATE_AM (address
masking) bit set.

We can't run the kernel with that bit set, so when the kernel accesses
userspace no address masking occurs.

Since a 32-bit process will have no mappings in that region we will
properly fault, so we don't try to handle this using access_ok(),
which can safely just be a NOP on sparc64.

Real faults from 32-bit processes should never generate such addresses
so a bug check was added long ago, and it barks in the logs if this
happens.

But it also barks when a kernel user access causes this condition, and
that _can_ happen.  For example, if a pointer passed into a system call
is "0xfffffffc" and the kernel access 4 bytes offset from that pointer.

Just handle such faults normally via the exception entries.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make get_user_insn() able to cope with huge PMDs.

Next, make do_fault_siginfo() more robust when get_user_insn() can't
actually fetch the instruction.  In particular, use the MMU announced
fault address when that happens, instead of calling
compute_effective_address() and computing garbage.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Mark the places when the system are in user or are in kernel.
This is used to make full dynticks system (tickless) --
CONFIG_NO_HZ_FULL dependence.
Signed-off-by: NKirill Tkhai <tkhai@yandex.ru>
CC: David Miller <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.

Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NMichal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: azurIt <azurit@pobox.sk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If our first THP installation for an MM is via the set_pmd_at() done
during khugepaged's collapsing we'll end up in tsb_grow() trying to do
a GFP_KERNEL allocation with several locks held.

Simply using GFP_ATOMIC in this situation is not the best option
because we really can't have this fail, so we'd really like to keep
this an order 0 GFP_KERNEL allocation if possible.

Also, doing the TSB allocation from khugepaged is a really bad idea
because we'll allocate it potentially from the wrong NUMA node in that
context.

So what we do is defer the hugepage TSB allocation until the first TLB
miss we take on a hugepage.  This is slightly tricky because we have
to handle two unusual cases:

1) Taking the first hugepage TLB miss in the window trap handler.
   We'll call the winfix_trampoline when that is detected.

2) An initial TSB allocation via TLB miss races with a hugetlb
   fault on another cpu running the same MM.  We handle this by
   unconditionally loading the TSB we see into the current cpu
   even if it's non-NULL at hugetlb_setup time.
Reported-by: NMeelis Roos <mroos@ut.ee>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Missing error types, attributes, and report fields.  Pad out
to 64-bytes.

Make string reporting cleaner and easier to extend in the future using
"const char *" arrays that index by either bit position, or absolute
field value.

Report the raw 64-byte error report as a sequence of u64s before the
annotated version.

Only report fields which are valid, given the context and the
attribute bits which are set.

For shutdown requests, use the local copy of the error report not the
one we just freed up back to the queue.  Also, use orderly_poweroff()
just like the Domain Services shutdown request code does.

If the real-address reported is "-1" (unknown) try to disassemble the
instruction to report the effective address of the access.  Only do
this in privileged mode.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is relatively easy since PMD's now cover exactly 4MB of memory.

Our PMD entries are 32-bits each, so we use a special encoding.  The
lowest bit, PMD_ISHUGE, determines the interpretation.  This is possible
because sparc64's page tables are purely software entities so we can use
whatever encoding scheme we want.  We just have to make the TLB miss
assembler page table walkers aware of the layout.

set_pmd_at() works much like set_pte_at() but it has to operate in two
page from a table of non-huge PTEs, so we have to queue up TLB flushes
based upon what mappings are valid in the PTE table.  In the second regime
we are going from huge-page to non-huge-page, and in that case we need
only queue up a single TLB flush to push out the huge page mapping.

We still have 5 bits remaining in the huge PMD encoding so we can very
likely support any new pieces of THP state tracking that might get added
in the future.

With lots of help from Johannes Weiner.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

.fault now can retry.  The retry can break state machine of .fault.  In
filemap_fault, if page is miss, ra->mmap_miss is increased.  In the second
try, since the page is in page cache now, ra->mmap_miss is decreased.  And
these are done in one fault, so we can't detect random mmap file access.

Add a new flag to indicate .fault is tried once.  In the second try, skip
ra->mmap_miss decreasing.  The filemap_fault state machine is ok with it.

I only tested x86, didn't test other archs, but looks the change for other
archs is obvious, but who knows :)
Signed-off-by: NShaohua Li <shaohua.li@fusionio.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit d065bd81
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e05
(x86,mm: make pagefault killable)

The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.

These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.

Port these changes to 64-bit sparc.
Signed-off-by: NKautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The nmi parameter indicated if we could do wakeups from the current
context, if not, we would set some state and self-IPI and let the
resulting interrupt do the wakeup.

For the various event classes:

  - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
    the PMI-tail (ARM etc.)
  - tracepoint: nmi=0; since tracepoint could be from NMI context.
  - software: nmi=[0,1]; some, like the schedule thing cannot
    perform wakeups, and hence need 0.

As one can see, there is very little nmi=1 usage, and the down-side of
not using it is that on some platforms some software events can have a
jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).

The up-side however is that we can remove the nmi parameter and save a
bunch of conditionals in fast paths.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Cree <mcree@orcon.net.nz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@elte.hu>

Just faults right now, will add other traps later.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As noted by Nick Piggin.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This allows the callers to now pass down the full set of FAULT_FLAG_xyz
flags to handle_mm_fault().  All callers have been (mechanically)
converted to the new calling convention, there's almost certainly room
for architectures to clean up their code and then add FAULT_FLAG_RETRY
when that support is added.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This builds upon eeabac73
("sparc64: Validate kernel generated fault addresses on sparc64.")

Upon further consideration, we actually should never see any
fault addresses for 32-bit tasks with the upper 32-bits set.

If it does every happen, by definition it's a bug.  Whatever
context created that fault would only have that fault satisfied
if we used the full 64-bit address.  If we truncate it, we'll
always fault the wrong address and we'll always loop faulting
forever.

So catch such conditions and mark them as errors always.  Log
the error and fail the fault.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to handle all of the cases of address calculation overflow
properly, we run sparc 32-bit processes in "address masking" mode
when running on a 64-bit kernel.

Address masking mode zeros out the top 32-bits of the address
calculated for every load and store instruction.

However, when we're in privileged mode we have to run with that
address masking mode disabled even when accessing userspace from
the kernel.

To "simulate" the address masking mode we clear the top-bits by
hand for 32-bit processes in the fault handler.

It is the responsibility of code in the compat layer to properly
zero extend addresses used to access userspace.  If this isn't
followed properly we can get into a fault loop.

Say that the user address is 0xf0000000 but for whatever reason
the kernel code sign extends this to 64-bit, and then the kernel
tries to access the result.

In such a case we'll fault on address 0xfffffffff0000000 but the fault
handler will process that fault as if it were to address 0xf0000000.
We'll loop faulting forever because the fault never gets satisfied.

So add a check specifically for this case, when the kernel is faulting
on a user address access and the addresses don't match up.

This code path is sufficiently slow path, and this bug is sufficiently
painful to diagnose, that this kind of bug check is warranted.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- move all sparc64/mm/ files to arch/sparc/mm/
- commonly named files are named _64.c
- add files to sparc/mm/Makefile preserving link order
- delete now unused sparc64/mm/Makefile
- sparc64 now finds mm/ in sparc
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

1) set_brkpt() is referenced by nothing and hasn't been used by anyone
   to my knowledge for many many years.  So just delete it.

2) add extern decl for do_sparc64_fault() in asm/pgtable_64.h
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch removes the CVS keywords that weren't updated for a long time
from comments.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Because of the new futex validation init handler, we have
to accept faults in init section text as well as the normal
kernel text.

Thanks to Tom Callaway for the bug report.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some parts of the kernel now do things like do *_user() accesses while
set_fs(KERNEL_DS) that fault on purpose.

See, for example, the code added by changeset
a0c1e907 ("futex: runtime enable pi
and robust functionality").

That trips up the ASI sanity checking we make in do_kernel_fault().

Just remove it for now.  Maybe we can add it back later with an added
conditional which looks at the current get_fs() value.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We have had complaints where a threaded application is left in a bad state
after one of it's threads is killed when we hit a VM: out_of_memory
condition.

Killing just one of the process threads can leave the application in a bad
state, whereas killing the entire process group would allow for the
application to restart, or be otherwise handled, and makes it very obvious
that something has gone wrong.

This change allows the entire process group to be taken down, rather
than just the one thread.
Signed-off-by: NWill Schmidt <will_schmidt@vnet.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It didn't handle that case at all, and now dump_stack()
can be implemented directly as show_stack(current, NULL)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch completes Linus's wish that the fault return codes be made into
bit flags, which I agree makes everything nicer.  This requires requires
all handle_mm_fault callers to be modified (possibly the modifications
should go further and do things like fault accounting in handle_mm_fault --
however that would be for another patch).

[akpm@linux-foundation.org: fix alpha build]
[akpm@linux-foundation.org: fix s390 build]
[akpm@linux-foundation.org: fix sparc build]
[akpm@linux-foundation.org: fix sparc64 build]
[akpm@linux-foundation.org: fix ia64 build]
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: NKyle McMartin <kyle@mcmartin.ca>
Acked-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Acked-by: NAndi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
[ Still apparently needs some ARM and PPC loving - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

And eliminate DIE_GPF while we're at it.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch moves the die notifier handling to common code.  Previous
various architectures had exactly the same code for it.  Note that the new
code is compiled unconditionally, this should be understood as an appel to
the other architecture maintainer to implement support for it aswell (aka
sprinkling a notify_die or two in the proper place)

arm had a notifiy_die that did something totally different, I renamed it to
arm_notify_die as part of the patch and made it static to the file it's
declared and used at.  avr32 used to pass slightly less information through
this interface and I brought it into line with the other architectures.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
[bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NBryan Wu <bryan.wu@analog.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

That way we'll have at least some debugging info even if
the stack dump explodes.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Overloading of page fault notification with the notify_die() has performance
issues(since the only interested components for page fault is kprobes and/or
kdb) and hence this patch introduces the new notifier call chain exclusively
for page fault notifications their by avoiding notifying unnecessary
components in the do_page_fault() code path.
Signed-off-by: NAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The worst part about this bug is what it would cause
a hugepage TSB to be allocated for every address space
since "0 >= 0".
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>