Commit Graph

953 Commits

Author SHA1 Message Date
Johannes Weiner
3e75a90219 [S390] use kzfree()
Use kzfree() instead of memset() + kfree().

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:29 +01:00
Stoyan Gaydarov
6aa0d3a922 [S390] BUG to BUG_ON changes
Signed-off-by: Stoyan Gaydarov <stoyboyker@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:28 +01:00
Michael Holzheu
59f2e69d0f [S390] zfcpdump: Prevent zcore from beeing built as a kernel module.
The zcore code switches to real addressing mode when creating a kernel dump.
This is not possible, if it is built as a kernel module. With this patch
zcore (zfcpdump) can't be built as a kernel module any more.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:28 +01:00
Frank Munzert
159d1ff8f6 [S390] Use csum_partial in checksum.h
The cksm function in system.h is duplicate to csum_partial in checksum.h.
Remove cksm and use csum_partial instead.

Signed-off-by: Frank Munzert <munzert@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:27 +01:00
Martin Schwidefsky
866ba28418 [S390] cleanup lowcore.h
The lowcore.h header has quite a lot of whitespace damage and a rather
wild collection of entries. Remove all that whitespace and tidy up the
order of the lowcore fields.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:27 +01:00
Martin Schwidefsky
da292bbe1f [S390] eliminate ipl_device from lowcore
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:27 +01:00
Martin Schwidefsky
7b4684880d [S390] eliminate cpuinfo_S390 structure
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:26 +01:00
Christian Borntraeger
2938af534d [S390] Fix comments in lowcore structure
This patch fixes two addresses in the comments for the
lowcore structure. Looks like an copy-paste bug.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:26 +01:00
Dan Smith
eaf1b6fbca [S390] Expose a constant for the number of words representing the CRs
We need to use this value in the checkpoint/restart code and would like to
have a constant instead of a magic '3'.

Cc: linux-s390@vger.kernel.org
Signed-off-by: Dan Smith <danms@us.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:25 +01:00
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
Martin Schwidefsky
504665a914 [S390] module function call optimization
Avoid the detour over the PLT if the branch target of a function call
in a module is in the range of the bras (16-bit) or brasl (32-bit)
instruction. The PLT is still generated but it is unused.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:24 +01:00
Heiko Carstens
e13ed9b270 [S390] bitops: remove likely annotations
likely/unlikely profiling revealed that none of the branches in bitops
is taken likely or unlikely. So remove the annotations.
In addition the generated code is shorter.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:23 +01:00
Hendrik Brueckner
ced2c8bcbc [S390] remove duplicate nul-termination of string
strlcpy() does already NUL-terminate the destination string.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:23 +01:00
Rusty Russell
6faf250789 [S390] allow usage of string functions in linux/string.h
In introducing a trivial "strstarts()" function in linux/string.h, we
hit the following error on s390:

In file included from include/linux/bitmap.h:8,
                 from include/linux/cpumask.h:142,
                 from include/linux/smp.h:12,
                 from /home/rusty/devel/kernel/patches/linux-2.6/arch/s390/include/asm/spinlock.h:14,
                 from include/linux/spinlock.h:88,
                 from include/linux/seqlock.h:29,
                 from include/linux/time.h:8,
                 from include/linux/stat.h:60,
                 from include/linux/module.h:10,
                 from arch/s390/lib/string.c:13:
include/linux/string.h: In function 'strstarts':
include/linux/string.h:124: error: implicit declaration of function 'strlen'
include/linux/string.h:124: warning: incompatible implicit declaration of built-in function 'strlen'

Because when including asm/string.h from arch/s390/lib/string.c we
don't declare the string ops we are about to define, and
linux/string.h barfs.

The fix is to declare them in this IN_ARCH_STRING_C case, but in
general I wonder if there's a neater fix.

Reported-by: linux-next
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:23 +01:00
Jan Glauber
d303b6fd85 [S390] qdio: report SIGA errors directly
Errors from SIGA instructions are stored in the per queue qdio_error
and reported back when the queue handler is called. That opens a race
when multiple error conditions occur simultanously.

Report SIGA errors immediately in the return value of do_QDIO so the
upper layer can react and SIGA errors no longer interfere with other
errors.

Move the SIGA error handling in qeth from the outbound handler to
qeth_flush_buffers.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
2009-03-26 15:24:22 +01:00
Gerald Schaefer
4b2a8b6043 [S390] kernel: Disable switch_amode by default
Disable switch_amode by default because pagetable walk on pre z9
hardware has negative performance impact.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:18 +01:00
Martin Schwidefsky
8283cb43ab [S390] clock sync mode flags
The clock sync mode flag CLOCK_SYNC_STP is not cleared when stp
is set offline. In this case the get_sync_clock() function returns
-EACCESS and the dasd driver will block all i/o until stp is enabled
again. In addition get_sync_clock can return -EACCESS if the clock is
not in sync instead of -EAGAIN.

Rework the stp/etr online handling to fix these problems.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:18 +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
Heiko Carstens
e3dd9c2da6 [S390] convert bitmap definitions to C
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
Heiko Carstens
7b886416df [S390] Remove CONFIG_MACHCHK_WARNING.
Everybody enables it so there is no point for an extra config option.

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
Heiko Carstens
f5daba1d41 [S390] split/move machine check handler code
Split machine check handler code and move it to cio and kernel code
where it belongs to. No functional change.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:10 +01:00
Sachin Sant
70193af918 [S390] Fix appldata build break with !NET
With CONFIG_NET not set appldata build breaks on s390.

arch/s390/appldata/built-in.o: In function appldata_get_net_sum_data:
appldata_net_sum.c:(.text+0x2684): undefined reference to dev_get_stats
appldata_net_sum.c:(.text+0x2688): undefined reference to init_net
appldata_net_sum.c:(.text+0x268c): undefined reference to init_net
appldata_net_sum.c:(.text+0x2694): undefined reference to dev_base_lock

The following patch fixes the issue for me.

Signed-off-by: Sachin Sant <sachinp@in.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:10 +01:00
Christian Borntraeger
92e6ecf392 [S390] Fix hypervisor detection for KVM
Currently we use the cpuid (via STIDP instruction) to recognize LPAR,
z/VM and KVM.
The architecture states, that bit 0-7 of STIDP returns all zero, and
if STIDP is executed in a virtual machine, the VM operating system
will replace bits 0-7 with FF.

KVM should not use FE to distinguish z/VM from KVM for interested
guests. The proper way to detect the hypervisor is the STSI (Store
System Information) instruction, which return information about the
hypervisors via function code 3, selector1=2, selector2=2.

This patch changes the detection routine of Linux to use STSI instead
of STIDP. This detection is earlier than bootmem, we have to use a
static buffer. Since STSI expects a 4kb block (4kb aligned) this
patch also changes the init.data alignment for s390. As this section
will be freed during boot, this should be no problem.

Patch is tested with LPAR, z/VM, KVM on LPAR, and KVM under z/VM.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:09 +01:00
Carsten Otte
702d9e584f [S390] check addressing mode in s390_enable_sie
The sie instruction requires address spaces to be switched
to run proper. This patch verifies that this is the case
in s390_enable_sie, otherwise the kernel would crash badly
as soon as the process runs into sie.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:09 +01:00
Christian Borntraeger
3324e60aaf [S390] lockdep: trace hardirq off in smp_send_stop
With lockdep we got the following trace after a panic:

Badness at /home/autobuild/BUILD/linux-2.6.28-20090204/kernel/lockdep.c:2878
[...]
Call Trace:
 [<0000000000176334>] lock_acquire+0x54/0xbc
 [<000000000050b4fe>] __atomic_notifier_call_chain+0x6e/0xdc
 [<000000000050b59c>] atomic_notifier_call_chain+0x30/0x44
 [<0000000000504274>] panic+0xd0/0x1e8
[...]
INFO: lockdep is turned off.
Last Breaking-Event-Address:
 [<0000000000170e62>] check_flags+0xae/0x15c
possible reason: unannotated irqs-off.

lockdep is right. We missed a trace_hardirq_off in our smp_send_stop
function and smp_send_stop is called before the panic call chain.

Reported-by: Mijo <Safradin mijo@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:08 +01:00
Heiko Carstens
5168ce2c64 [S390] cputime: initialize per thread timer values on fork
Initialize per thread timer values instead of just copying them from
the parent. That way it is easily possible to tell how much time a
thread spent in user/system context.
Doesn't fix a bug, this is just for debugging purposes.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:07 +01:00
Heiko Carstens
cbdc229245 [S390] arch/s390/kernel/process.c: fix whitespace damage
Fix all the whitespace damage in process.c, especially copy_thread().
Next patch will add code to copy_thread() which needs to 'fixed' first.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:07 +01:00
Heiko Carstens
94f5b09d97 [S390] move sysinfo.c from drivers/s390 to arch/s390/kernel
All in sysinfo.c is core kernel code and not driver code. So move it
to arch/s390/kernel. Also includes some small cleanups.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:06 +01:00
Stefan Weinhuber
f3eb5384cf [S390] dasd: add High Performance FICON support
To support High Performance FICON, the DASD device driver has to
translate I/O requests into the new transport mode control words (TCW)
instead of the traditional (command mode) CCW requests.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:05 +01:00
Stefan Weinhuber
b44b0ab3ba [S390] dasd: add large volume support
The dasd device driver will now support ECKD devices with more then
65520 cylinders.
In the traditional ECKD adressing scheme each track is addressed
by a 16-bit cylinder and 16-bit head number. The new addressing
scheme makes use of the fact that the actual number of heads is
never larger then 15, so 12 bits of the head number can be redefined
to be part of the cylinder address.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:05 +01:00
Heiko Carstens
59fa4392dd [S390] page fault: invoke oom-killer
s390 arch backend for 1c0fe6e3bd
"mm: invoke oom-killer from page fault".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:03 +01:00
Frank Munzert
099b765139 [S390] Automatic IPL after dump
Provide new shutdown action "dump_reipl" for automatic ipl after dump.

Signed-off-by: Frank Munzert <munzert@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-03-26 15:24:03 +01:00
Christian Borntraeger
d7fd5f1e3b [S390] fix dump_stack vs. %p and (null)
The s390 implemenation of dump_stack uses %p to display stack content.
Since d97106ab53 (Make %p print '(null)'
for NULL pointers) this causes a strange output for dump_stack:

[...]
Process basename (pid: 8822, task: 00000000b2ece038, ksp: 00000000b24d7b38)
04000000b5685c00 00000000b24d7760 0000000000000002 (null)
00000000b24d7800 00000000b24d7778 00000000b24d7778 00000000001052fe
(null) 00000000b24d7b38 (null) 000000000000000a
000000000000000d (null) 00000000b24d7760 00000000b24d77d8
000000000051a7e8 00000000001052fe 00000000b24d7760 00000000b24d77b0
Call Trace:
[...]

This patch changes our dump_stack to use the appropriate %x format.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:02 +01:00
Martin Schwidefsky
0fb1d9bcbc [S390] make page table upgrade work again
After TASK_SIZE now gives the current size of the address space the
upgrade of a 64 bit process from 3 to 4 levels of page table  needs
to use the arch_mmap_check hook to catch large mmap lengths. The
get_unmapped_area* functions need to check for -ENOMEM from the
arch_get_unmapped_area*, upgrade the page table and retry.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:13 +01:00
Martin Schwidefsky
f481bfafd3 [S390] make page table walking more robust
Make page table walking on s390 more robust. The current code requires
that the pgd/pud/pmd/pte loop is only done for address ranges that are
below the end address of the last vma of the address space. But this
is not always true, e.g. the generic page table walker does not guarantee
this. Change TASK_SIZE/TASK_SIZE_OF to reflect the current size of the
address space. This makes the generic page table walker happy but it
breaks the upgrade of a 3 level page table to a 4 level page table.
To make the upgrade work again another fix is required.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:13 +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
Heiko Carstens
cf08734380 [S390] ftrace/mcount: fix kernel stack backchain
With packed stack the backchain is at a different location.
Just use __SF_BACKCHAIN as an offset to store the backchain.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:12 +01:00
Heiko Carstens
f55d63854e [S390] topology: define SD_MC_INIT to fix performance regression
The default values for SD_MC_INIT cause an additional cpu usage of up
to 40% on some network benchmarks compared to the plain SD_CPU_INIT
values. So just define SD_MC_INIT to SD_CPU_INIT.
More tuning needs to be done.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:12 +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
Linus Torvalds
9c1a774705 Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: ixp4xx - Fix qmgr_request_queue build failure
  crypto: api - Fix module load deadlock with fallback algorithms
2009-03-03 17:05:08 -08:00
Herbert Xu
a760a6656e crypto: api - Fix module load deadlock with fallback algorithms
With the mandatory algorithm testing at registration, we have
now created a deadlock with algorithms requiring fallbacks.
This can happen if the module containing the algorithm requiring
fallback is loaded first, without the fallback module being loaded
first.  The system will then try to test the new algorithm, find
that it needs to load a fallback, and then try to load that.

As both algorithms share the same module alias, it can attempt
to load the original algorithm again and block indefinitely.

As algorithms requiring fallbacks are a special case, we can fix
this by giving them a different module alias than the rest.  Then
it's just a matter of using the right aliases according to what
algorithms we're trying to find.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-02-26 14:06:31 +08:00
Heiko Carstens
23d75d9cad [S390] fix "mem=" handling in case of standby memory
Standby memory detected with the sclp interface gets always registered
with add_memory calls without considering the limitationt that the
"mem=" kernel paramater implies.
So fix this and only register standby memory that is below the specified
limit.
This fixes zfcpdump since it uses "mem=32M". In case there is appr.
2GB standby memory present all of usable memory would be used for the
struct pages needed for standby memory.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-02-19 15:19:19 +01:00
Christian Borntraeger
d5cd0343d2 [S390] Fix timeval regression on s390
commit aa5e97ce4b
[PATCH] improve precision of process accounting.

Introduced a timing regression:
-bash-3.2# time ls
real    0m0.006s
user    0m1.754s
sys     0m1.094s

The problem was introduced by an error in cputime_to_timeval.
Cputime is now 1/4096 microsecond, therefore, we have to divide
the remainder with 4096 to get the microseconds.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-02-19 15:19:19 +01:00
Sheng Yang
ad8ba2cd44 KVM: Add kvm_arch_sync_events to sync with asynchronize events
kvm_arch_sync_events is introduced to quiet down all other events may happen
contemporary with VM destroy process, like IRQ handler and work struct for
assigned device.

For kvm_arch_sync_events is called at the very beginning of kvm_destroy_vm(), so
the state of KVM here is legal and can provide a environment to quiet down other
events.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-02-15 02:47:36 +02:00
Martin Schwidefsky
95ec807e0a [S390] Update default configuration.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-02-11 10:37:40 +01:00
Sachin Sant
0addff8151 [S390] Fix init irq proc build break.
Embed init_irq_proc(s390) within CONFIG_PROC_FS to fix a build break.

Signed-off-by : Sachin Sant <sachinp@in.ibm.com>
2009-02-11 10:37:39 +01:00
Martin Schwidefsky
d5e842c4b7 [S390] vdso: fix per cpu vdso pointer in lowcore
The vdso_per_cpu_data entry in the lowcore structure uses __u32
instead of __u64. If the data page is above 4GB the pointer is
truncated and the kernel crashes.

Reported-by: Mijo Safradin <mijo@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-02-11 10:37:39 +01:00
Michael Holzheu
e34a628041 [S390] Add missing compat system call wrappers.
Add wrapper functions for the following compat system calls:
* readahead
* sendfile64
* tkill
* tgkill
* keyctl
This ensures that the high order bits of the parameter registers are correctly
sign extended.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-23 16:40:29 +01:00
Heiko Carstens
179cb81aa1 [S390] etr/stp: fix possible deadlock
Precreate stop_machine threads in case the machine supports ETR/STP.
Otherwise we might deadlock if a time sync operation gets scheduled
and the creation of stop_machine threads would cause disk I/O.
This is just the minimal fix.
The real fix would be to only precreate stop_machine threads if
ETR/STP is actually used. But that would be a rather large and
complicated patch.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-23 16:40:29 +01:00
Heiko Carstens
f9a2f797fc [S390] cputime: fix lowcore initialization on cpu hotplug
On (initial) cpu hotplug the lowcore values for user_timer and
system_timer don't get initialized like they would get on each
process schedule.
On initial start of secondary cpus this leads to the situation
where per thread user/system_timer values are larger than the
corresponding contents of the lowcore. When later calculating
time spent in user/system context the result can be negative.

So for cpu hotplug we should manually initialize lowcore values.

Fixes this bug:

Kernel BUG at 000ec080 [verbose debug info unavailable]
fixpoint divide exception: 0009 [#1] PREEMPT SMP
Modules linked in:
CPU: 10 Not tainted 2.6.28 #4
Process sysctl (pid: 975, task: 3fa752e0, ksp: 3fbebca0)
Krnl PSW : 070c1000 800ec080 (show_stat+0x390/0x5fc)
           R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0
Krnl GPRS: 7fffffff fefc7ce5 3faec080 003879ae
           00000001 01388000 7fffffff 01388000
           00000000 00000000 0049ad50 3fbebcf8
           01388000 002f51a8 800ec1fe 3fbebcf8
Krnl Code: 800ec076: 9001b188           stm     %r0,%r1,392(%r11)
           800ec07a: 9801b0c0           lm      %r0,%r1,192(%r11)
           800ec07e: 1d05               dr      %r0,%r5
          >800ec080: 9001b0c0           stm     %r0,%r1,192(%r11)
           800ec084: 5860b0c4           l       %r6,196(%r11)
           800ec088: 1806               lr      %r0,%r6
           800ec08a: 8c800001           srdl    %r8,1
           800ec08e: 1d87               dr      %r8,%r7
Call Trace:
([<00000000000ec1ee>] show_stat+0x4fe/0x5fc)
 [<00000000000c13e8>] seq_read+0xc4/0x3ac
 [<00000000000e4796>] proc_reg_read+0x6e/0x9c
 [<00000000000a6a44>] vfs_read+0x78/0x100
 [<00000000000a6ba8>] sys_read+0x40/0x80
 [<00000000000234a8>] sysc_do_restart+0x1a/0x1e

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-23 16:40:28 +01:00