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>
When running a 31-bit ptrace, on either an s390 or s390x kernel,
reads and writes into a padding area in struct user_regs_struct32
will result in a kernel panic.
This is also known as CVE-2008-1514.
Test case available here:
http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/user-area-padding.c?cvsroot=systemtap
Steps to reproduce:
1) wget the above
2) gcc -o user-area-padding-31bit user-area-padding.c -Wall -ggdb2 -D_GNU_SOURCE -m31
3) ./user-area-padding-31bit
<panic>
Test status
-----------
Without patch, both s390 and s390x kernels panic. With patch, the test case,
as well as the gdb testsuite, pass without incident, padding area reads
returning zero, writes ignored.
Nb: original version returned -EINVAL on write attempts, which broke the
gdb test and made the test case slightly unhappy, Jan Kratochvil suggested
the change to return 0 on write attempts.
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Tested-by: Jan Kratochvil <jan.kratochvil@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
ext4 does not work on s390 because ext2_find_next_bit is broken. Fortunately
this function is only used by ext4. The function uses ffs which does not work
analog to ffz. The result of ffs has an offset of 1 which is not taken into
account. To fix this use the low level __ffs_word function directly instead
of the ill defined ffs.
In addition the patch improves find_next_zero_bit and ext2_find_next_zero_bit
by passing the bit offset into __ffz_word instead of adding it after the
function call returned.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove the now unneeded s390_idle.lock spinlock initialization after
Josef Sipek did it the right way in arch/s390/kernel/process.c.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZE, because control
page is used for not only code on some platform. For example in kexec
jump, it is used for data and stack too.
[akpm@linux-foundation.org: unbreak powerpc and arm, finish conversion]
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'kvm-updates-2.6.27' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
KVM: s390: Fix kvm on IBM System z10
KVM: Advertise synchronized mmu support to userspace
KVM: Synchronize guest physical memory map to host virtual memory map
KVM: Allow browsing memslots with mmu_lock
KVM: Allow reading aliases with mmu_lock
Fix these two (false positive) warnings by adding an __init annoation:
WARNING: vmlinux.o(.text+0x7e6a): Section mismatch in reference from the function stp_reset() to the function .init.text:__alloc_bootmem()
The function stp_reset() references
the function __init __alloc_bootmem().
This is often because stp_reset lacks a __init
annotation or the annotation of __alloc_bootmem is wrong.
WARNING: vmlinux.o(.text+0x7ece): Section mismatch in reference from the function stp_reset() to the function .init.text:free_bootmem()
The function stp_reset() references
the function __init free_bootmem().
This is often because stp_reset lacks a __init
annotation or the annotation of free_bootmem is wrong.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The result of the diag 0x260 call is not always what one would expect.
So just remove it.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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>
During startup we check if diag308 works using diag 308 subcode 6,
which stores the actual ipl information. This fails with rc = 0x102, if
the system has been ipled from the HMC using load from CD or load from file.
In the case of rc = 0x102 we have to assume that diag 308 is working,
since it still can be used to ipl from an alternative device.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The z10 system supports large pages, kvm-s390 doesnt.
Make sure that we dont advertise large pages to avoid the guest crashing as
soon as the guest kernel activates DAT.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
The lctl(g) instructions require a specific alignment for the parameters.
The architecture requires a specification program check if these alignments
are not used. Enforcing this alignment also removes a possible host BUG,
since the get_guest functions check for proper alignment and emits a BUG.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Lets fix the name for the lctlg instruction...
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
The current interrupt handling on s390 misbehaves on an error case. On s390
each cpu has the prefix area (lowcore) for interrupt delivery. This memory
must always be available. If we fail to access the prefix area for a guest
on interrupt delivery the configuration is completely unusable. There is no
point in sending another program interrupt to an inaccessible lowcore.
Furthermore, we should not bug the host kernel, because this can be triggered
by userspace. I think the guest kernel itself can not trigger the problem, as
SET PREFIX and SIGNAL PROCESSOR SET PREFIX both check that the memory is
available and sane. As this is a userspace bug (e.g. setting the wrong guest
offset, unmapping guest memory) we should kill the userspace process instead
of BUGing the host kernel.
In the long term we probably should notify the userspace process about this
problem.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
All registers are unsigned long types. This patch changes all occurences
of guestaddr in gaccess from u64 to unsigned long.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
KVM_CAP_USER_MEMORY is used by s390, therefore, we should advertise it.
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Remove arch-specific show_mem() in favor of the generic version.
This also removes the following redundant information display:
- pages in swapcache, printed by show_swap_cache_info()
where show_mem() calls show_free_areas(), which calls
show_swap_cache_info().
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Heiko Carstens
Jarod Wilson
Martin Schwidefsky
Eric Sandeen
Josef 'Jeff' Sipek
Huang Ying
Linus Torvalds
Gerald Schaefer
Michael Holzheu
Christian Borntraeger
Rusty Russell
Carsten Otte
Johannes Weiner