UltraSPARC has special sets of global registers which are switched to
for certain trap types.  There is one set for MMU related traps, one
set of Interrupt Vector processing, and another set (called the
Alternate globals) for all other trap types.

For what seems like forever we've hard coded the values in some of
these trap registers.  Some examples include:

1) Interrupt Vector global %g6 holds current processors interrupt
   work struct where received interrupts are managed for IRQ handler
   dispatch.

2) MMU global %g7 holds the base of the page tables of the currently
   active address space.

3) Alternate global %g6 held the current_thread_info() value.

Such hardcoding has resulted in some serious issues in many areas.
There are some code sequences where having another register available
would help clean up the implementation.  Taking traps such as
cross-calls from the OBP firmware requires some trick code sequences
wherein we have to save away and restore all of the special sets of
global registers when we enter/exit OBP.

We were also using the IMMU TSB register on SMP to hold the per-cpu
area base address, which doesn't work any longer now that we actually
use the TSB facility of the cpu.

The implementation is pretty straight forward.  One tricky bit is
getting the current processor ID as that is different on different cpu
variants.  We use a stub with a fancy calling convention which we
patch at boot time.  The calling convention is that the stub is
branched to and the (PC - 4) to return to is in register %g1.  The cpu
number is left in %g6.  This stub can be invoked by using the
__GET_CPUID macro.

We use an array of per-cpu trap state to store the current thread and
physical address of the current address space's page tables.  The
TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this
table, it uses __GET_CPUID and also clobbers %g1.

TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load
the current processor's IRQ software state into %g6.  It also uses
__GET_CPUID and clobbers %g1.

Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the
current address space's page tables into %g7, it clobbers %g1 and uses
__GET_CPUID.

Many refinements are possible, as well as some tuning, with this stuff
in place.
Signed-off-by: David S. Miller <davem@davemloft.net>

Taking a nod from the powerpc port.

With the per-cpu caching of both the page allocator and SLAB, the
pgtable quicklist scheme becomes relatively silly and primitive.
Signed-off-by: David S. Miller <davem@davemloft.net>

Unlike the virtual page tables, the new TSB scheme does not
require this ugly hack.
Signed-off-by: David S. Miller <davem@davemloft.net>

We now use the TSB hardware assist features of the UltraSPARC
MMUs.

SMP is currently knowingly broken, we need to find another place
to store the per-cpu base pointers.  We hid them away in the TSB
base register, and that obviously will not work any more :-)

Another known broken case is non-8KB base page size.

Also noticed that flush_tlb_all() is not referenced anywhere, only
the internal __flush_tlb_all() (local cpu only) is used by the
sparc64 port, so we can get rid of flush_tlb_all().

The kernel gets it's own 8KB TSB (swapper_tsb) and each address space
gets it's own private 8K TSB.  Later we can add code to dynamically
increase the size of per-process TSB as the RSS grows.  An 8KB TSB is
good enough for up to about a 4MB RSS, after which the TSB starts to
incur many capacity and conflict misses.

We even accumulate OBP translations into the kernel TSB.

Another area for refinement is large page size support.  We could use
a secondary address space TSB to handle those.
Signed-off-by: David S. Miller <davem@davemloft.net>

this changes if() BUG(); constructs to BUG_ON() which is
cleaner and can better optimized away
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

The patch "[SPARC64]: Get rid of fast IRQ feature"
moved the the code from arch/sparc64/kernel/entry.S:
      lduba           [%g7] ASI_PHYS_BYPASS_EC_E, %g5
      or              %g5, AUXIO_AUX1_FTCNT, %g5
      stba            %g5, [%g7] ASI_PHYS_BYPASS_EC_E
      andn            %g5, AUXIO_AUX1_FTCNT, %g5
      stba            %g5, [%g7] ASI_PHYS_BYPASS_EC_E
to arch/sparc64/kernel/irq.c:
              val = readb(auxio_register);
              val |= AUXIO_AUX1_FTCNT;
              writeb(val, auxio_register);
              val &= AUXIO_AUX1_FTCNT;
              writeb(val, auxio_register);
This looks like it it missing a bitwise not, which is reintroduced
by this patch.

Due to lack of a floppy device, I could not test it, but it looks
evident.
Signed-off-by: Bernhard R Link <brlink@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

This address is going to be obsolete, so I should update it.

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  [MIPS] SB1: Check for -mno-sched-prolog if building corelis debug kernel.
  [MIPS] Sibyte: Fix race in sb1250_gettimeoffset().
  [MIPS] Sibyte: Fix interrupt timer off by one bug.
  [MIPS] Sibyte: Fix M_SCD_TIMER_INIT and M_SCD_TIMER_CNT wrong field width.
  [MIPS] Protect more of timer_interrupt() by xtime_lock.
  [MIPS] Work around bad code generation for <asm/io.h>.
  [MIPS] Simple patch to power off DBAU1200
  [MIPS] Fix DBAu1550 software power off.
  [MIPS] local_r4k_flush_cache_page fix
  [MIPS] SB1: Fix interrupt disable hazard.
  [MIPS] Get rid of the IP22-specific code in arclib.
  Update MAINTAINERS entry for MIPS.

The 40-bit DMA workaround recently implemented for 5714, 5715, and
5780 needs to be expanded because there may be other tg3 devices
behind the EPB Express to PCIX bridge in the 5780 class device.

For example, some 4-port card or mother board designs have 5704 behind
the 5714.

All devices behind the EPB require the 40-bit DMA workaround.

Thanks to Chris Elmquist again for reporting the problem and testing
the patch.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the AX.25 dialect chosen by the sysadmin is set to DAMA master / 3
(or DAMA slave / 2, if CONFIG_AX25_DAMA_SLAVE=n) ax25_kick() will fall
through the switch statement without calling ax25_send_iframe() or any
other function that would eventually free skbn thus leaking the packet.

Fix by restricting the sysctl inferface to allow only actually supported
AX.25 dialects.

The system administration mistake needed for this to happen is rather
unlikely, so this is an uncritical hole.

Coverity #651.
Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

VIDEO_CX88_ALSA should not be between VIDEO_CX88_DVB and
VIDEO_CX88_DVB_ALL_FRONTENDS

When cx88-alsa was added to cx88/Kconfig, it was added in between
VIDEO_CX88_DVB and VIDEO_CX88_DVB_ALL_FRONTENDS.  This caused
undesireable effects to the appearance of the menu options in
menuconfig.

This fix reorders cx88-alsa and cx88-dvb in Kconfig, to match saa7134,
and restore the correct menuconfig appearance.
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Fixed em28xx based system lockup, device needs to be initialized before
starting the isoc transfer otherwise the system will completly lock up.
Signed-off-by: Markus Rechberger <mrechberger@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

sys_unshare() does mmput(new_mm).  This is not enough if we have
mm->core_waiters.

This patch is a temporary fix for soon to be released 2.6.16.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
[ Checked with Uli: "I'm not planning to use unshare(CLONE_VM).  It's
  not needed for any functionality planned so far.  What we (as in Red
  Hat) need unshare() for now is the filesystem side." ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
From Dave Johnson <djohnson+linuxmips@sw.starentnetworks.com>:
    
sb1250_gettimeoffset() simply reads the current cpu 0 timer remaining
value, however once this counter reaches 0 and the interrupt is raised,
it immediately resets and begins to count down again.
    
If sb1250_gettimeoffset() is called on cpu 1 via do_gettimeofday() after
the timer has reset but prior to cpu 0 processing the interrupt and
taking write_seqlock() in timer_interrupt() it will return a full value
(or close to it) causing time to jump backwards 1ms. Once cpu 0 handles
the interrupt and timer_interrupt() gets far enough along it will jump
forward 1ms.
    
Fix this problem by implementing mips_hpt_*() on sb1250 using a spare
timer unrelated to the existing periodic interrupt timers. It runs at
1Mhz with a full 23bit counter.  This eliminated the custom
do_gettimeoffset() for sb1250 and allowed use of the generic
fixed_rate_gettimeoffset() using mips_hpt_*() and timerhi/timerlo.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
From Dave Johnson <djohnson+linuxmips@sw.starentnetworks.com>:
    
The timers need to be loaded with 1 less than the desired interval not
the interval itself.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
From Dave Johnson <djohnson+linuxmips@sw.starentnetworks.com>:
    
Field width should be 23 bits not 20 bits.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
From Dave Johnson <djohnson+linuxmips@sw.starentnetworks.com>:

* do_timer() expects the arch-specific handler to take the lock as it
  modifies jiffies[_64] and xtime.
* writing timerhi/lo in timer_interrupt() will mess up
  fixed_rate_gettimeoffset() which reads timerhi/lo.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
If a call to set_io_port_base() was being followed by usage of
mips_io_port_base in the same function gcc was possibly using the old
value due to some clever abuse of const.  Adding a barrier will keep
the optimization and result in correct code with latest gcc.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Signed-off-by: Matej Kupljen <matej.kupljen@ultra.si>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
If dcache_size != icache_size or dcache_size != scache_size, or
set-associative cache, icache/scache does not flushed properly.  Make
blast_?cache_page_indexed() masks its index value correctly.  Also,
use physical address for physically indexed pcache/scache.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
The SB1 core has a three cycle interrupt disable hazard but we were
wrongly treating it as fully interlocked.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

    
This breaks the kernel build if sgiwd93 was configured as a module.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

It is broken, the condition is checked out of socket lock. It is
wonderful the bug survived for so long time.

[ This fixes bugzilla #6233:
  race condition in tcp_sendmsg when connection became established ]
Signed-off-by: David S. Miller <davem@davemloft.net>

Lee Revell reported 28ms latency when process with lots of swapped memory
exits.

2.6.15 introduced a latency regression when unmapping: in accounting the
zap_work latency breaker, pte_none counted 1, pte_present PAGE_SIZE, but a
swap entry counted nothing at all.  We think of pages present as the slow
case, but Lee's trace shows that free_swap_and_cache's radix tree lookup
can make a lot of work - and we could have been doing it many thousands of
times without a latency break.

Move the zap_work update up to account swap entries like pages present.
This does account non-linear pte_file entries, and unmap_mapping_range
skipping over swap entries, by the same amount even though they're quick:
but neither of those cases deserves complicating the code (and they're
treated no worse than they were in 2.6.14).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Jiri Benc <jbenc@suse.cz> reported that modpost would stop with SIGABRT if
used with long filepaths.
The error looked like:
>   Building modules, stage 2.
>   MODPOST
> *** glibc detected *** scripts/mod/modpost: realloc(): invalid next size:
+0x0809f588 ***
> [...]

Fix this by allocating at least the required memory + SZ bytes each time.
Before we sometimes ended up allocating too little memory resuting in the
glibc detected bug above.  Based on patch originally submitted by: Jiri
Benc <jbenc@suse.cz>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

A user can use nfsservctl() to spam the logs.

This can happen because the arguments to the nfsservctl() system call are
versioned.  This is a good thing.  However, when a bad version is detected,
the kernel prints a message and then returns an error.
Signed-off-by: Peter Staubach <staubach@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

We can call try_to_release_page() with PagePrivate off and a valid
page->mapping This may cause all sorts of trouble for the filesystem
*_releasepage() handlers.  XFS bombs out in that case.

Lock the page before checking for page private.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

The dm-stripe target currently does not enforce that the size of a stripe
device be a multiple of the chunk-size.  Under certain conditions, this can
lead to I/O requests going off the end of an underlying device.  This
test-case shows one example.

echo "0 100 linear /dev/hdb1 0" | dmsetup create linear0
echo "0 100 linear /dev/hdb1 100" | dmsetup create linear1
echo "0 200 striped 2 32 /dev/mapper/linear0 0 /dev/mapper/linear1 0" | \
   dmsetup create stripe0
dd if=/dev/zero of=/dev/mapper/stripe0 bs=1k

This will produce the output:
dd: writing '/dev/mapper/stripe0': Input/output error
97+0 records in
96+0 records out

And in the kernel log will be:
attempt to access beyond end of device
dm-0: rw=0, want=104, limit=100

The patch will check that the table size is a multiple of the stripe
chunk-size when the table is created, which will prevent the above striped
device from being created.

This should not affect tools like LVM or EVMS, since in all the cases I can
think of, striped devices are always created with the sizes being a
multiple of the chunk-size.

The size of a stripe device must be a multiple of its chunk-size.

(akpm: that typecast is quite gratuitous)
Signed-off-by: Kevin Corry <kevcorry@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Bryce reported a bug wherein offlining CPU0 (on x86 box) and then
subsequently onlining it resulted in a lockup.

On x86, CPU0 is never offlined.  The subsequent attempt to online CPU0
doesn't take that into account.  It actually tries to bootup the already
booted CPU.  Following patch fixes the problem (as acknowledged by Bryce).
Please consider for inclusion in 2.6.16.

Check if cpu is already online.
Signed-off-by: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

There is a d_drop in dir_release which caused problems as it invalidates
dcache entries too soon.  This was likely a part of the wierd cwd behavior
folks were seeing.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

When the posix-timer signal is ignored then the timer is rearmed by the
callback function.  The requeue pending accounting has to be fixed up else
the state might be wrong.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

The pointer to the current time interpolator and the current list of time
interpolators are typically only changed during bootup.  Adding
__read_mostly takes them away from possibly hot cachelines.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Currently the migration of anonymous pages will silently fail if no swap is
setup.  This patch makes page migration functions check for available swap
and fail with -ENODEV if no swap space is available.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

The sighand pointer only needs the rcu_read_lock on the
read side.  So only depending on task_lock protection
when setting this pointer is not enough.  We also need
a memory barrier to ensure the initialization is seen first.

Use rcu_assign_pointer as it does this for us, and clearly
documents that we are setting an rcu readable pointer.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Adrian Bunk wrote:
> The Coverity checker spotted the following two array overflows in
> drivers/net/chelsio/sge.c (in both cases, the arrays contain 3
> elements):
[snip]

This is a bug. The array should contain 2 elements.  Here is the fix.
Signed-off-by: Scott Bardone <sbardone@chelsio.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

	return -E_NO_BIG_ENDIAN_TESTING;

[E1000]: Fix 4 missed endianness conversions on RX descriptor fields.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>