linux-toradex.git/arch/s390, branch v3.0.95

s390: move dummy io_remap_pfn_range() to asm/pgtable.h

2013-05-08T02:57:28+00:00

commit 4f2e29031e6c67802e7370292dd050fd62f337ee upstream.

Commit b4cbb197c7e7 ("vm: add vm_iomap_memory() helper function") added
a helper function wrapper around io_remap_pfn_range(), and every other
architecture defined it in .

The s390 choice of  may make sense, but is not very convenient
for this case, and gratuitous differences like that cause unexpected errors like this:

   mm/memory.c: In function 'vm_iomap_memory':
   mm/memory.c:2439:2: error: implicit declaration of function 'io_remap_pfn_range' [-Werror=implicit-function-declaration]

Glory be the kbuild test robot who noticed this, bisected it, and
reported it to the guilty parties (ie me).

Signed-off-by: Linus Torvalds 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

signal: Define __ARCH_HAS_SA_RESTORER so we know whether to clear sa_restorer

2013-04-05T17:16:35+00:00

Vaguely based on upstream commit 574c4866e33d 'consolidate kernel-side
struct sigaction declarations'.

flush_signal_handlers() needs to know whether sigaction::sa_restorer
is defined, not whether SA_RESTORER is defined.  Define the
__ARCH_HAS_SA_RESTORER macro to indicate this.

Signed-off-by: Ben Hutchings 
Cc: Al Viro 
Signed-off-by: Greg Kroah-Hartman

s390/mm: fix flush_tlb_kernel_range()

2013-03-20T19:58:53+00:00

commit f6a70a07079518280022286a1dceb797d12e1edf upstream.

Our flush_tlb_kernel_range() implementation calls __tlb_flush_mm() with
&init_mm as argument. __tlb_flush_mm() however will only flush tlbs
for the passed in mm if its mm_cpumask is not empty.

For the init_mm however its mm_cpumask has never any bits set. Which in
turn means that our flush_tlb_kernel_range() implementation doesn't
work at all.

This can be easily verified with a vmalloc/vfree loop which allocates
a page, writes to it and then frees the page again. A crash will follow
almost instantly.

To fix this remove the cpumask_empty() check in __tlb_flush_mm() since
there shouldn't be too many mms with a zero mm_cpumask, besides the
init_mm of course.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390/kvm: Fix store status for ACRS/FPRS fix

2013-03-03T22:09:07+00:00

In 3.0.67, commit 58c9ce6fad8e00d9726447f939fe7e78e2aec891 (s390/kvm:
Fix store status for ACRS/FPRS), upstream commit
15bc8d8457875f495c59d933b05770ba88d1eacb, added a call to
save_access_regs to save ACRS. But we do not have ARCS in kvm_run in
3.0 yet, so this results in:
arch/s390/kvm/kvm-s390.c: In function 'kvm_s390_vcpu_store_status':
arch/s390/kvm/kvm-s390.c:593: error: 'struct kvm_run' has no member named 's'

Fix it by saving guest_acrs which is where ARCS are in 3.0.

Signed-off-by: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

s390/kvm: Fix store status for ACRS/FPRS

2013-02-28T14:32:24+00:00

commit 15bc8d8457875f495c59d933b05770ba88d1eacb upstream.

On store status we need to copy the current state of registers
into a save area. Currently we might save stale versions:
The sie state descriptor doesnt have fields for guest ACRS,FPRS,
those registers are simply stored in the host registers. The host
program must copy these away if needed. We do that in vcpu_put/load.

If we now do a store status in KVM code between vcpu_put/load, the
saved values are not up-to-date. Lets collect the ACRS/FPRS before
saving them.

This also fixes some strange problems with hotplug and virtio-ccw,
since the low level machine check handler (on hotplug a machine check
will happen) will revalidate all registers with the content of the
save area.

Signed-off-by: Christian Borntraeger 
Signed-off-by: Gleb Natapov 
Signed-off-by: Greg Kroah-Hartman

s390/time: fix sched_clock() overflow

2013-01-21T19:44:58+00:00

commit ed4f20943cd4c7b55105c04daedf8d63ab6d499c upstream.

Converting a 64 Bit TOD format value to nanoseconds means that the value
must be divided by 4.096. In order to achieve that we multiply with 125
and divide by 512.
When used within sched_clock() this triggers an overflow after appr.
417 days. Resulting in a sched_clock() return value that is much smaller
than previously and therefore may cause all sort of weird things in
subsystems that rely on a monotonic sched_clock() behaviour.

To fix this implement a tod_to_ns() helper function which converts TOD
values without overflow and call this function from both places that
open coded the conversion: sched_clock() and kvm_s390_handle_wait().

Reviewed-by: Martin Schwidefsky 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390/gup: add missing TASK_SIZE check to get_user_pages_fast()

2012-11-26T19:34:34+00:00

commit d55c4c613fc4d4ad2ba0fc6fa2b57176d420f7e4 upstream.

When walking page tables we need to make sure that everything
is within bounds of the ASCE limit of the task's address space.
Otherwise we might calculate e.g. a pud pointer which is not
within a pud and dereference it.
So check against TASK_SIZE (which is the ASCE limit) before
walking page tables.

Reviewed-by: Gerald Schaefer 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390/compat: fix mmap compat system calls

2012-08-26T22:12:10+00:00

commit e85871218513c54f7dfdb6009043cb638f2fecbe upstream.

The native 31 bit and the compat behaviour for the mmap system calls differ:

In native 31 bit mode the passed in address for the mmap system call will be
unmodified passed to sys_mmap_pgoff().
In compat mode however the passed in address will be modified with
compat_ptr() which masks out the most significant bit.

The result is that in native 31 bit mode each mmap request (with MAP_FIXED)
will fail where the most significat bit is set, while in compat mode it
may succeed.

This odd behaviour was introduced with d3815898 "[S390] mmap: add missing
compat_ptr conversion to both mmap compat syscalls".

To restore a consistent behaviour accross native and compat mode this
patch functionally reverts the above mentioned commit.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390/pfault: fix task state race

2012-06-01T07:12:53+00:00

commit d5e50a51ccbda36b379aba9d1131a852eb908dda upstream.

When setting the current task state to TASK_UNINTERRUPTIBLE this can
race with a different cpu. The other cpu could set the task state after
it inspected it (while it was still TASK_RUNNING) to TASK_RUNNING which
would change the state from TASK_UNINTERRUPTIBLE to TASK_RUNNING again.

This race was always present in the pfault interrupt code but didn't
cause anything harmful before commit f2db2e6c "[S390] pfault: cpu hotplug
vs missing completion interrupts" which relied on the fact that after
setting the task state to TASK_UNINTERRUPTIBLE the task would really
sleep.
Since this is not necessarily the case the result may be a list corruption
of the pfault_list or, as observed, a use-after-free bug while trying to
access the task_struct of a task which terminated itself already.

To fix this, we need to get a reference of the affected task when receiving
the initial pfault interrupt and add special handling if we receive yet
another initial pfault interrupt when the task is already enqueued in the
pfault list.

Signed-off-by: Heiko Carstens 
Reviewed-by: Martin Schwidefsky 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

S390: fix tlb flushing for page table pages

2012-04-22T23:21:45+00:00

commit cd94154cc6a28dd9dc271042c1a59c08d26da886 upstream.

Git commit 36409f6353fc2d7b6516e631415f938eadd92ffa "use generic RCU
page-table freeing code" introduced a tlb flushing bug. Partially revert
the above git commit and go back to s390 specific page table flush code.

For s390 the TLB can contain three types of entries, "normal" TLB
page-table entries, TLB combined region-and-segment-table (CRST) entries
and real-space entries. Linux does not use real-space entries which
leaves normal TLB entries and CRST entries. The CRST entries are
intermediate steps in the page-table translation called translation paths.
For example a 4K page access in a three-level page table setup will
create two CRST TLB entries and one page-table TLB entry. The advantage
of that approach is that a page access next to the previous one can reuse
the CRST entries and needs just a single read from memory to create the
page-table TLB entry. The disadvantage is that the TLB flushing rules are
more complicated, before any page-table may be freed the TLB needs to be
flushed. 

In short: the generic RCU page-table freeing code is incorrect for the
CRST entries, in particular the check for mm_users < 2 is troublesome.

This is applicable to 3.0+ kernels.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman