linux-stable.git/arch/s390, branch linux-4.7.y

s390: get_user() should zero on failure

2016-09-24T08:09:39+00:00

commit fd2d2b191fe75825c4c7a6f12f3fef35aaed7dd7 upstream.

Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

KVM: s390: don't use current->thread.fpu.* when accessing registers

2016-09-24T08:09:29+00:00

commit a7d4b8f2565ad0dfdff9a222d1d87990c73b36e8 upstream.

As the meaning of these variables and pointers seems to change more
frequently, let's directly access our save area, instead of going via
current->thread.

Right now, this is broken for set/get_fpu. They simply overwrite the
host registers, as the pointers to the current save area were turned
into the static host save area.

Fixes: 3f6813b9a5e0 ("s390/fpu: allocate 'struct fpu' with the task_struct")
Reported-by: Hao QingFeng 
Signed-off-by: David Hildenbrand 
Signed-off-by: Christian Borntraeger 
Signed-off-by: Greg Kroah-Hartman

s390/mm: don't drop errors in get_guest_storage_key

2016-08-20T16:10:51+00:00

commit c427c42cd612719e8fb8b5891cc9761e7770024e upstream.

Commit 1e133ab296f3 ("s390/mm: split arch/s390/mm/pgtable.c") changed
the return value of get_guest_storage_key to an unsigned char, resulting
in -EFAULT getting interpreted as a valid storage key.

Reviewed-by: Christian Borntraeger 
Signed-off-by: David Hildenbrand 
Signed-off-by: Christian Borntraeger 
Signed-off-by: Greg Kroah-Hartman

s390/mm: fix gmap tlb flush issues

2016-08-20T16:10:51+00:00

commit f045402984404ddc11016358411e445192919047 upstream.

__tlb_flush_asce() should never be used if multiple asce belong to a mm.

As this function changes mm logic determining if local or global tlb
flushes will be neded, we might end up flushing only the gmap asce on all
CPUs and a follow up mm asce flushes will only flush on the local CPU,
although that asce ran on multiple CPUs.

The missing tlb flushes will provoke strange faults in user space and even
low address protections in user space, crashing the kernel.

Fixes: 1b948d6caec4 ("s390/mm,tlb: optimize TLB flushing for zEC12")
Reported-by: Sascha Silbe 
Acked-by: Martin Schwidefsky 
Signed-off-by: David Hildenbrand 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390: fix test_fp_ctl inline assembly contraints

2016-06-28T07:24:28+00:00

The test_fp_ctl function is used to test if a given value is a valid
floating-point control. The inline assembly in test_fp_ctl uses an
incorrect constraint for the 'orig_fpc' variable. If the compiler
chooses the same register for 'fpc' and 'orig_fpc' the test_fp_ctl()
function always returns true. This allows user space to trigger
kernel oopses with invalid floating-point control values on the
signal stack.

This problem has been introduced with git commit 4725c86055f5bbdcdf
"s390: fix save and restore of the floating-point-control register"

Cc: stable@vger.kernel.org # v3.13+
Reviewed-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

Revert "s390/kdump: Clear subchannel ID to signal non-CCW/SCSI IPL"

2016-06-28T07:24:27+00:00

This reverts commit 852ffd0f4e23248b47531058e531066a988434b5.

There are use cases where an intermediate boot kernel (1) uses kexec
to boot the final production kernel (2). For this scenario we should
provide the original boot information to the production kernel (2).
Therefore clearing the boot information during kexec() should not
be done.

Cc: stable@vger.kernel.org # v3.17+
Reported-by: Steffen Maier 
Signed-off-by: Michael Holzheu 
Reviewed-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390: get rid of superfluous __GFP_REPEAT

2016-06-25T00:23:52+00:00

__GFP_REPEAT has a rather weak semantic but since it has been introduced
around 2.6.12 it has been ignored for low order allocations.

page_table_alloc then uses the flag for a single page allocation.  This
means that this flag has never been actually useful here because it has
always been used only for PAGE_ALLOC_COSTLY requests.

Link: http://lkml.kernel.org/r/1464599699-30131-14-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko 
Acked-by: Heiko Carstens 
Cc: Martin Schwidefsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2016-06-20T17:18:58+00:00

Pull s390 fixes from Martin Schwidefsky:
 "Two more bugs fixes for 4.7:

   - a KVM regression introduced with the pgtable.c code split

   - a perf issue with two hardware PMUs using a shared event context"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/cpum_cf: use perf software context for hardware counters
  KVM: s390/mm: Fix CMMA reset during reboot

s390/cpum_cf: use perf software context for hardware counters

2016-06-16T10:08:49+00:00

On s390, there are two different hardware PMUs for counting and
sampling.  Previously, both PMUs have shared the perf_hw_context
which is not correct and, recently, results in this warning:

    ------------[ cut here ]------------
    WARNING: CPU: 5 PID: 1 at kernel/events/core.c:8485 perf_pmu_register+0x420/0x428
    Modules linked in:
    CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.7.0-rc1+ #2
    task: 00000009c5240000 ti: 00000009c5234000 task.ti: 00000009c5234000
    Krnl PSW : 0704c00180000000 0000000000220c50 (perf_pmu_register+0x420/0x428)
               R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
    Krnl GPRS: ffffffffffffffff 0000000000b15ac6 0000000000000000 00000009cb440000
               000000000022087a 0000000000000000 0000000000b78fa0 0000000000000000
               0000000000a9aa90 0000000000000084 0000000000000005 000000000088a97a
               0000000000000004 0000000000749dd0 000000000022087a 00000009c5237cc0
    Krnl Code: 0000000000220c44: a7f4ff54            brc     15,220aec
               0000000000220c48: 92011000           mvi     0(%r1),1
              #0000000000220c4c: a7f40001           brc     15,220c4e
              >0000000000220c50: a7f4ff12           brc     15,220a74
               0000000000220c54: 0707               bcr     0,%r7
               0000000000220c56: 0707               bcr     0,%r7
               0000000000220c58: ebdff0800024       stmg    %r13,%r15,128(%r15)
               0000000000220c5e: a7f13fe0           tmll    %r15,16352
    Call Trace:
    ([<000000000022087a>] perf_pmu_register+0x4a/0x428)
    ([<0000000000b2c25c>] init_cpum_sampling_pmu+0x14c/0x1f8)
    ([<0000000000100248>] do_one_initcall+0x48/0x140)
    ([<0000000000b25d26>] kernel_init_freeable+0x1e6/0x2a0)
    ([<000000000072bda4>] kernel_init+0x24/0x138)
    ([<000000000073495e>] kernel_thread_starter+0x6/0xc)
    ([<0000000000734958>] kernel_thread_starter+0x0/0xc)
    Last Breaking-Event-Address:
     [<0000000000220c4c>] perf_pmu_register+0x41c/0x428
    ---[ end trace 0c6ef9f5b771ad97 ]---

Using the perf_sw_context is an option because the cpum_cf PMU does
not use interrupts.  To make this more clear, initialize the
capabilities in the PMU structure.

Signed-off-by: Hendrik Brueckner 
Suggested-by: Peter Zijlstra 
Acked-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

KVM: s390/mm: Fix CMMA reset during reboot

2016-06-13T13:58:09+00:00

commit 1e133ab296f ("s390/mm: split arch/s390/mm/pgtable.c") factored
out the page table handling code from __gmap_zap and  __s390_reset_cmma
into ptep_zap_unused and added a simple flag that tells which one of the
function (reset or not) is to be made. This also changed the behaviour,
as it also zaps unused page table entries on reset.
Turns out that this is wrong as s390_reset_cmma uses the page walker,
which DOES NOT take the ptl lock.

The most simple fix is to not do the zapping part on reset (which uses
the walker)

Signed-off-by: Christian Borntraeger 
Fixes: 1e133ab296f ("s390/mm: split arch/s390/mm/pgtable.c")
Cc: stable@vger.kernel.org # 4.6+
Signed-off-by: Martin Schwidefsky