Commit graph

58 commits

Author SHA1 Message Date
Martin Schwidefsky
b11b533427 [S390] Improve address space mode selection.
Introduce user_mode to replace the two variables switch_amode and
s390_noexec. There are three valid combinations of the old values:
  1) switch_amode == 0 && s390_noexec == 0
  2) switch_amode == 1 && s390_noexec == 0
  3) switch_amode == 1 && s390_noexec == 1
They get replaced by
  1) user_mode == HOME_SPACE_MODE
  2) user_mode == PRIMARY_SPACE_MODE
  3) user_mode == SECONDARY_SPACE_MODE
The new kernel parameter user_mode=[primary,secondary,home] lets
you choose the address space mode the user space processes should
use. In addition the CONFIG_S390_SWITCH_AMODE config option
is removed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:33 +01:00
Gerald Schaefer
af9d2ff9af [S390] Add EX_TABLE for addressing exception in usercopy functions.
This patch adds an EX_TABLE entry to mvc{p|s|os} usercopy functions that
may be called with KERNEL_DS. In combination with collaborative memory
management, kernel pages marked as unused may trigger an adressing exception
in the usercopy functions. This fixes an unhandled addressing exception bug
where strncpy_from_user() is used with len > strnlen and KERNEL_DS, crossing
a page boundary to an unused page.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06 10:35:10 +02:00
Heiko Carstens
0cd6a403e8 [S390] Provide arch specific mdelay implementation.
Use an own implementation instead of the common code udelay loop.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06 10:35:08 +02:00
Christian Borntraeger
78d81f2f84 [S390] Fix enabled udelay for short delays.
When udelay() gets called with a delay that would expire before the
next clock event it reprograms the clock comparator.
When the interrupt happens the clock comparator won't be resetted
therefore the interrupt condition doesn't get cleared.
The result is an endless timer interrupt loop until the next clock
event would expire (stored in lowcore).
So udelay() usually would wait much longer for small delays than it
should.

Fix this by disabling the local tick which makes sure that the clock
comparator will be resetted when a timer interrupt happens.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06 10:35:08 +02:00
Heiko Carstens
5075baca2e [S390] add __ucmpdi2() helper function
Provide __ucmpdi2() helper function on 31 bit so we don't run
again and again in compile errors like this one:

kernel/built-in.o: In function `T.689':
perf_counter.c:(.text+0x56c86): undefined reference to `__ucmpdi2'

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-07-07 16:37:53 +02:00
Heiko Carstens
bb8c29caff [S390] udelay: disable lockdep to avoid false positives
Our udelay implementation enables interrupts to receive a special timer
interrupt regardless of the context it is called from.
This might lead to false positive lockdep reports. Since lockdep isn't
aware of the fact that only a single interrupt source is enabled it
warns about possible deadlocks that in reality won't happen, like
the one below.
To fix this disable lockdep before enabling interrupts.

[ 254.040888] =================================
[ 254.040904] [ INFO: inconsistent lock state ]
[ 254.040910] 2.6.30 #9
[ 254.040914] ---------------------------------
[ 254.040920] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[ 254.040927] swapper/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[ 254.040934] (sch->lock){?.-...}, at: [<00000000002e4778>] ccw_device_timeout+0x48/0x2f0
[ 254.040961] {IN-HARDIRQ-W} state was registered at:
[ 254.040969] [<0000000000096f74>] __lock_acquire+0x9d4/0x188c
[ 254.040985] [<0000000000097f68>] lock_acquire+0x13c/0x16c
[ 254.040998] [<00000000004527e0>] _spin_lock+0x74/0xb8
[ 254.041016] [<0000000000457eb2>] do_IRQ+0xde/0x208
[ 254.041031] [<000000000002d190>] io_return+0x0/0x8
[ 254.041049] [<0000000000029faa>] vtime_stop_cpu+0xbe/0x114
[ 254.041066] irq event stamp: 259629
[ 254.041076] hardirqs last enabled at (259628): [<000000000045238e>] _spin_unlock_irq+0x5e/0x9c
[ 254.041095] hardirqs last disabled at (259629): [<000000000045292e>] _spin_lock_irq+0x4a/0xc4
[ 254.041126] softirqs last enabled at (259614): [<000000000006500e>] __do_softirq+0x296/0x2b0
[ 254.041137] softirqs last disabled at (259619): [<0000000000024cf6>] do_softirq+0x102/0x108
[ 254.041147]
[ 254.041148] other info that might help us debug this:
[ 254.041153] 2 locks held by swapper/0:
[ 254.041157] #0: (&priv->timer){+.-...}, at: [<000000000006bf9a>] run_timer_softirq+0x19a/0x340
[ 254.041170] #1: (sch->lock){?.-...}, at: [<00000000002e4778>] ccw_device_timeout+0x48/0x2f0
[ 254.041182]
[ 254.041310] Call Trace:
[ 254.041313] ([<00000000000174fc>] show_trace+0x16c/0x170)
[ 254.041321] [<0000000000017578>] show_stack+0x78/0x104
[ 254.041327] [<000000000044d0ca>] dump_stack+0xc6/0xd4
[ 254.041342] [<00000000000949b4>] print_usage_bug+0x1c8/0x1fc
[ 254.041353] [<0000000000094e8a>] mark_lock+0x4a2/0x670
[ 254.041364] [<00000000000950e2>] mark_held_locks+0x8a/0xb4
[ 254.041375] [<0000000000095398>] trace_hardirqs_on_caller+0x74/0x1ac
[ 254.041388] [<00000000000954fa>] trace_hardirqs_on+0x2a/0x38
[ 254.041402] [<000000000025f1ec>] __udelay_disabled+0xac/0xfc
[ 254.041419] [<000000000025f432>] __udelay+0x12a/0x148
[ 254.041433] [<00000000002d64d8>] cio_commit_config+0x170/0x290
[ 254.041451] [<00000000002d6978>] cio_disable_subchannel+0x120/0x1cc
[ 254.041468] [<00000000002e32a4>] ccw_device_recog_done+0x54/0x2f4
[ 254.041485] [<00000000002e3638>] ccw_device_sense_id_done+0x50/0x90
[ 254.041508] [<00000000002e615a>] snsid_callback+0xfa/0x3a8
[ 254.041515] [<00000000002dd96c>] ccwreq_stop+0x80/0x90
[ 254.041523] [<00000000002dda8e>] ccw_request_timeout+0xc2/0xd0
[ 254.041530] [<00000000002e2f70>] ccw_device_request_event+0x58/0x90
[ 254.041537] [<00000000002e47ae>] ccw_device_timeout+0x7e/0x2f0
[ 254.041555] [<000000000006c02a>] run_timer_softirq+0x22a/0x340
[ 254.041566] [<0000000000064eb0>] __do_softirq+0x138/0x2b0
[ 254.041578] [<0000000000024cf6>] do_softirq+0x102/0x108
[ 254.041590] [<00000000000647ce>] irq_exit+0xee/0x114
[ 254.041603] [<0000000000457d88>] do_extint+0x130/0x17c
[ 254.041617] [<000000000002d41e>] ext_no_vtime+0x1e/0x22
[ 254.041631] [<0000000000029faa>] vtime_stop_cpu+0xbe/0x114
[ 254.041646] ([<0000000000029f58>] vtime_stop_cpu+0x6c/0x114)
[ 254.041662] [<000000000001d842>] cpu_idle+0x122/0x1c0
[ 254.041679] [<00000000004482c6>] start_secondary+0xce/0xe0
[ 254.041696] [<0000000000000000>] 0x0
[ 254.041715] [<0000000000000000>] 0x0
[ 254.041745] INFO: lockdep is turned off.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-07-07 16:37:51 +02:00
Linus Torvalds
d06063cc22 Move FAULT_FLAG_xyz into handle_mm_fault() callers
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: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-21 13:08:22 -07:00
Heiko Carstens
ce58ae6f7f [S390] implement interrupt-enabling rwlocks
arch backend for f5f7eac41d
"Allow rwlocks to re-enable interrupts".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 10:27:29 +02:00
Heiko Carstens
1edad85b16 [S390] use compiler builtin versions of strlen/strcpy/strcat
Use builtin variants if gcc 4 or newer is used to compile the kernel.
Generates better code than the asm variants.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:24 +01:00
Heiko Carstens
1485c5c884 [S390] move EXPORT_SYMBOLs to definitions
Move all EXPORT_SYMBOLs to their corresponding definitions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:11 +01:00
Gerald Schaefer
2887fc5aa6 [S390] Dont check for pfn_valid() in uaccess_pt.c
pfn_valid() actually checks for a valid struct page and not for a
valid pfn. Using xip mappings w/o struct pages, this will result in
-EFAULT returned by the (page table walk) user copy functions,
even though there is valid memory. Those user copy functions don't
need a struct page, so this patch just removes the pfn_valid() check.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:13 +01:00
Martin Schwidefsky
4fa81ed277 [S390] __div64_31 broken for CONFIG_MARCH_G5
The implementation of __div64_31 for G5 machines is broken. The comments
in __div64_31 are correct, only the code does not do what the comments
say. The part "If the remainder has overflown subtract base and increase
the quotient" is only partially realized, the base is subtracted correctly
but the quotient is only increased if the dividend had the last bit set.
Using the correct instruction fixes the problem.

Cc: stable@kernel.org
Reported-by: Frans Pop <elendil@planet.nl>
Tested-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:12 +01:00
Heiko Carstens
5a0d0e6537 [S390] Move private simple udelay function to arch/s390/lib/delay.c.
Move cio's private simple udelay function to lib/delay.c and turn it
into something much more readable. So we have all implementations
at one place.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-10 21:33:58 +02:00
Heiko Carstens
d3d238c774 [S390] nohz: Fix __udelay.
This fixes a regression that came with 934b2857cc
("[S390] nohz/sclp: disable timer on synchronous waits.").
If udelay() gets called from a disabled context it sets the clock comparator
to a value where it expects the next interrupt. When the interrupt happens
the clock comparator gets not reset and therefore the interrupt condition
doesn't get cleared. The result is an endless timer interrupt loop.

In addition this patch fixes also the following:

rcutorture reveals that our __udelay implementation is still buggy,
since it might schedule tasklets, but prevents their execution:

NOHZ: local_softirq_pending 42
NOHZ: local_softirq_pending 02
NOHZ: local_softirq_pending 142
NOHZ: local_softirq_pending 02

To fix this we make sure that only the clock comparator interrupt
is enabled when the enabled wait psw is loaded.
Also no code gets called anymore which might schedule tasklets.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-03 21:55:54 +02:00
Heiko Carstens
934b2857cc [S390] nohz/sclp: disable timer on synchronous waits.
sclp_sync_wait wait synchronously for an sclp interrupt and disables
timer interrupts. However on the irq enter paths there is an extra
check if a timer interrupt would be due and calls the timer callback.
This would schedule softirqs in the wrong context.
So introduce local_tick_enable/disable which prevents this.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-08-01 16:39:30 +02:00
Heiko Carstens
ccf183e469 [S390] uaccess_mvcos: #ifdef config dependent code.
arch/s390/lib/uaccess_mvcos.c:166:
 warning: 'strnlen_user_mvcos' defined but not used
arch/s390/lib/uaccess_mvcos.c:186:
 warning: 'strncpy_from_user_mvcos' defined but not used

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-04-30 13:38:46 +02:00
Mathieu Desnoyers
47494f6a84 [S390] remove -traditional
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-04-30 13:38:44 +02:00
Heiko Carstens
3f12ebce6a [S390] uaccess: Always access the correct address space.
The current uaccess page table walk code assumes at a few places that
any access is a user space access. This is not correct if somebody
has issued a set_fs(KERNEL_DS) in advance.
Add code which checks which address space we are in and with this make
sure we access the correct address space. This way we get also rid of
the dirty
if (!currrent-mm)
	return -EFAULT;
hack in futex_atomic_cmpxchg_pt.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-17 07:47:06 +02:00
Heiko Carstens
5a62b19219 [S390] Convert s390 to GENERIC_CLOCKEVENTS.
This way we get rid of s390's NO_IDLE_HZ and use the generic dynticks
variant instead. In addition we get high resolution timers for free.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-17 07:47:05 +02:00
Heiko Carstens
504e75d0ed [S390] futex: let futex_atomic_cmpxchg_pt survive early functional tests.
a0c1e9073e "futex: runtime enable pi and
robust functionality" introduces a test wether futex in atomic stuff
works or not.
It does that by writing to address 0 of the kernel address space. This
will crash on older machines where addressing mode switching is enabled
but where the mvcos instruction is not available. Page table walking is
done by hand and therefore the code tries to access current->mm which
is NULL.
Therefore add an extra check, so we survive the early test.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-03-20 17:33:46 +01:00
Heiko Carstens
d5b02b3ff1 [S390] Fix futex_atomic_cmpxchg_std inline assembly.
Add missing exception table entry so that the kernel can handle
proctection exceptions as well on the cs instruction. Currently only
specification exceptions are handled correctly.
The missing entry allows user space to crash the kernel.

Cc: stable <stable@kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-02-19 15:29:35 +01:00
Hisashi Hifumi
894cdde26b [S390] do local_irq_restore while spinning in spin_lock_irqsave.
In s390's spin_lock_irqsave, interrupts remain disabled while
spinning. In other architectures like x86 and powerpc, interrupts are
re-enabled while spinning if IRQ is not masked before spin_lock_irqsave
is called.

The following patch re-enables interrupts through local_irq_restore
while spinning for a lock acquisition.
This can improve system response.

[heiko.carstens@de.ibm.com: removed saving of pc]

Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-01-26 14:11:31 +01:00
Heiko Carstens
3b4beb3175 [S390] Remove owner_pc member from raw_spinlock_t.
Used to contain the address of the holder of the lock. But since the
spinlock code is not inlined anymore all locks contain the same address
anyway. And since in addtition nobody complained about that for ages
its obviously unused. So remove it.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-01-26 14:11:14 +01:00
Martin Schwidefsky
190a1d722a [S390] 4level-fixup cleanup
Get independent from asm-generic/4level-fixup.h

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-10-22 12:52:49 +02:00
Martin Schwidefsky
e4aa402e7a [S390] Introduce follow_table in uaccess_pt.c
Define and use follow_table inline in uaccess_pt.c to simplify
the code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-10-22 12:52:49 +02:00
Serge E. Hallyn
b460cbc581 pid namespaces: define is_global_init() and is_container_init()
is_init() is an ambiguous name for the pid==1 check.  Split it into
is_global_init() and is_container_init().

A cgroup init has it's tsk->pid == 1.

A global init also has it's tsk->pid == 1 and it's active pid namespace
is the init_pid_ns.  But rather than check the active pid namespace,
compare the task structure with 'init_pid_ns.child_reaper', which is
initialized during boot to the /sbin/init process and never changes.

Changelog:

	2.6.22-rc4-mm2-pidns1:
	- Use 'init_pid_ns.child_reaper' to determine if a given task is the
	  global init (/sbin/init) process. This would improve performance
	  and remove dependence on the task_pid().

	2.6.21-mm2-pidns2:

	- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
	  ppc,avr32}/traps.c for the _exception() call to is_global_init().
	  This way, we kill only the cgroup if the cgroup's init has a
	  bug rather than force a kernel panic.

[akpm@linux-foundation.org: fix comment]
[sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
[bunk@stusta.de: kernel/pid.c: remove unused exports]
[sukadev@us.ibm.com: Fix capability.c to work with threaded init]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:37 -07:00
Nick Piggin
83c54070ee mm: fault feedback #2
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: Nick 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: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Still apparently needs some ARM and PPC loving - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:41 -07:00
Martin Schwidefsky
8a88367088 [S390] Bogomips calculation for 64 bit.
The bogomips calculation triggered via reading from /proc/cpuinfo
can return incorrect values if the qrnnd assembly is called with a
pointer in %r2 with any of the upper 32 bits set.
Fix this by using 64 bit division / remainder operation provided by
gcc instead of calling the assembly.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-07-10 11:24:47 +02:00
David S. Miller
cb8c181f28 [S390]: Fix build on 31-bit.
Allow s390 to properly override the generic
__div64_32() implementation by:

1) Using obj-y for div64.o in s390's makefile instead
   of lib-y

2) Adding the weak attribute to the generic implementation.

Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:28:53 -07:00
Martin Schwidefsky
bf6f6aa46f [S390] prevent softirqs if delay is called disabled
The new delay implementation uses the clock comparator and an external
interrupt even if it is called disabled for interrupts. To do this
all external interrupt source except clock comparator are switched of
before enabling external interrupts. The external interrupt at the
end of the delay period may not execute softirqs or we can end up in a
dead-lock.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-21 10:55:00 +01:00
Heiko Carstens
4d284cac76 [S390] Avoid excessive inlining.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05 21:18:53 +01:00
Martin Schwidefsky
31ee4b2f40 [S390] Calibrate delay and bogomips.
Preset the bogomips number to the cpu capacity value reported by
store system information in SYSIB 1.2.2. This value is constant
for a particular machine model and can be used to determine
relative performance differences between machines.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05 21:18:31 +01:00
Martin Schwidefsky
d54853ef8c [S390] ETR support.
This patch adds support for clock synchronization to an external time
reference (ETR). The external time reference sends an oscillator
signal and a synchronization signal every 2^20 microseconds to keep
the TOD clocks of all connected servers in sync. For availability
two ETR units can be connected to a machine. If the clock deviates
for more than the sync-check tolerance all cpus get a machine check
that indicates that the clock is out of sync. For the lovely details
how to get the clock back in sync see the code below.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05 21:18:19 +01:00
Gerald Schaefer
c1821c2e97 [S390] noexec protection
This provides a noexec protection on s390 hardware. Our hardware does
not have any bits left in the pte for a hw noexec bit, so this is a
different approach using shadow page tables and a special addressing
mode that allows separate address spaces for code and data.

As a special feature of our "secondary-space" addressing mode, separate
page tables can be specified for the translation of data addresses
(storage operands) and instruction addresses. The shadow page table is
used for the instruction addresses and the standard page table for the
data addresses.
The shadow page table is linked to the standard page table by a pointer
in page->lru.next of the struct page corresponding to the page that
contains the standard page table (since page->private is not really
private with the pte_lock and the page table pages are not in the LRU
list).
Depending on the software bits of a pte, it is either inserted into
both page tables or just into the standard (data) page table. Pages of
a vma that does not have the VM_EXEC bit set get mapped only in the
data address space. Any try to execute code on such a page will cause a
page translation exception. The standard reaction to this is a SIGSEGV
with two exceptions: the two system call opcodes 0x0a77 (sys_sigreturn)
and 0x0aad (sys_rt_sigreturn) are allowed. They are stored by the
kernel to the signal stack frame. Unfortunately, the signal return
mechanism cannot be modified to use an SA_RESTORER because the
exception unwinding code depends on the system call opcode stored
behind the signal stack frame.

This feature requires that user space is executed in secondary-space
mode and the kernel in home-space mode, which means that the addressing
modes need to be switched and that the noexec protection only works
for user space.
After switching the addressing modes, we cannot use the mvcp/mvcs
instructions anymore to copy between kernel and user space. A new
mvcos instruction has been added to the z9 EC/BC hardware which allows
to copy between arbitrary address spaces, but on older hardware the
page tables need to be walked manually.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05 21:18:17 +01:00
Heiko Carstens
2b67fc4606 [S390] Get rid of a lot of sparse warnings.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05 21:16:47 +01:00
Heiko Carstens
d8ad075ef6 [S390] don't call handle_mm_fault() if in an atomic context.
There are several places in the futex code where a spin_lock is held
and still uaccesses happen. Deadlocks are avoided by increasing the
preempt count. The pagefault handler will then not take any locks
but will immediately search the fixup tables.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-01-09 10:18:50 +01:00
Heiko Carstens
22155914b6 [S390] uaccess_pt: add missing down_read() and convert to is_init().
Doesn't seem to be a good idea to duplicate code :)

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-12-08 15:53:49 +01:00
Peter Zijlstra
a866374aec [PATCH] mm: pagefault_{disable,enable}()
Introduce pagefault_{disable,enable}() and use these where previously we did
manual preempt increments/decrements to make the pagefault handler do the
atomic thing.

Currently they still rely on the increased preempt count, but do not rely on
the disabled preemption, this might go away in the future.

(NOTE: the extra barrier() in pagefault_disable might fix some holes on
       machines which have too many registers for their own good)

[heiko.carstens@de.ibm.com: s390 fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:21 -08:00
Gerald Schaefer
59f35d53fd [S390] Add dynamic size check for usercopy functions.
Use a wrapper for copy_to/from_user to chose the best usercopy method.
The mvcos instruction is better for sizes greater than 256 bytes, if
mvcos is not available a page table walk is better for sizes greater
than 1024 bytes. Also removed the redundant copy_to/from_user_std_small
functions.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-12-04 15:40:45 +01:00
Martin Schwidefsky
3c1fcfe229 [PATCH] Directed yield: direct yield of spinlocks for s390.
Use the new diagnose 0x9c in the spinlock implementation for s390.  It
yields the remaining timeslice of the virtual cpu that tries to acquire a
lock to the virtual cpu that is the current holder of the lock.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:22 -07:00
Martin Schwidefsky
94c12cc7d1 [S390] Inline assembly cleanup.
Major cleanup of all s390 inline assemblies. They now have a common
coding style. Quite a few have been shortened, mainly by using register
asm variables. Use of the EX_TABLE macro helps  as well. The atomic ops,
bit ops and locking inlines new use the Q-constraint if a newer gcc
is used.  That results in slightly better code.

Thanks to Christian Borntraeger for proof reading the changes.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-28 16:56:43 +02:00
Martin Schwidefsky
52149ba6b0 [S390] user readable uninitialised kernel memory.
A user space program can read uninitialised kernel memory
by appending to a file from a bad address and then reading
the result back. The cause is the copy_from_user function
that does not clear the remaining bytes of the kernel
buffer after it got a fault on the user space address.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-28 16:56:03 +02:00
Martin Schwidefsky
d9f7a745d5 [S390] __div64_32 for 31 bit.
The clocksource infrastructure introduced with commit
ad596171ed broke 31 bit s390.
The reason is that the do_div() primitive for 31 bit always
had a restriction: it could only divide an unsigned 64 bit
integer by an unsigned 31 bit integer. The clocksource code
now uses do_div() with a base value that has the most
significant bit set. The result is that clock->cycle_interval
has a funny value which causes the linux time to jump around
like mad.
The solution is "obvious": implement a proper __div64_32
function for 31 bit s390.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-28 16:55:39 +02:00
Gerald Schaefer
6c2a9e6df6 [S390] Use alternative user-copy operations for new hardware.
This introduces new user-copy operations which are optimized for
copying more than 256 Bytes on new hardware.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-20 15:59:44 +02:00
Gerald Schaefer
d02765d1af [S390] Make user-copy operations run-time configurable.
Introduces a struct uaccess_ops which allows setting user-copy
operations at run-time.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-20 15:59:42 +02:00
Martin Schwidefsky
af313e5a4f [S390] broken copy_in_user function.
The copy_in_user primitive does not work as advertised. If the source
and target area are available copy_in_user copies one byte too much.
If one of the memory areas is not available it does not copy as much
data as it can, but up to 257 bytes less.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-08-30 14:33:30 +02:00
Heiko Carstens
d2c993d845 [S390] Fix sparse warnings.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-07-12 16:41:55 +02:00
Jörn Engel
6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Christian Ehrhardt
96567161de [PATCH] s390: Increase spinlock retry code performance
Currently the code tries up to spin_retry times to grab a lock using the cs
instruction.  The cs instruction has exclusive access to a memory region
and therefore invalidates the appropiate cache line of all other cpus.  If
there is contention on a lock this leads to cache line trashing.  This can
be avoided if we first check wether a cs instruction is likely to succeed
before the instruction gets actually executed.

Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-09 19:47:38 -08:00
Gerald Schaefer
331c465914 [PATCH] s390: fix strnlen_user return value
strnlen_user is supposed to return then length count + 1 if no terminating \0
is found, and it should return 0 on exception.  Found by David Howells
<dhowells@redhat.com>.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-08 14:14:01 -08:00