linux-stable.git/arch/s390/kernel/process.c, branch linux-4.2.y

s390/process: fix sfpc inline assembly

2015-07-13T09:02:18+00:00

The sfpc inline assembly within execve_tail() may incorrectly set bits
28-31 of the sfpc instruction to a value which is not zero.
These bits however are currently unused and therefore should be zero
so we won't get surprised if these bits will be used in the future.

Therefore remove the second operand from the inline assembly.

Cc: 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390: remove 31 bit support

2015-03-25T10:49:33+00:00

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/process: free vx save area when releasing tasks

2015-02-10T15:39:05+00:00

If a task uses vector registers, a save area is allocated to save/restore
register states.  Free the save area when releasing the task.

Found the Memory leak with kmemleak:

unreferenced object 0x72885e00 (size 512):
  comm "vx-test", pid 26123, jiffies 4294945635 (age 256.810s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 01 db 71 06 41  .............q.A
    00 00 00 00 00 00 00 00 24 f7 a9 a7 51 94 79 bb  ........$...Q.y.
  backtrace:
    [<00000000002d1c8a>] kmem_cache_alloc_trace+0x272/0x3d0
    [<00000000001014ac>] alloc_vector_registers+0x54/0x138
    [<00000000001017c8>] data_exception+0x158/0x1b0
    [<00000000008b551e>] pgm_check_handler+0x13e/0x180
    [<00000000800008b6>] 0x800008b6

Signed-off-by: Hendrik Brueckner 
Signed-off-by: Martin Schwidefsky

s390: avoid z13 cache aliasing

2015-01-22T11:15:59+00:00

Avoid cache aliasing on z13 by aligning shared objects to multiples
of 512K. The virtual addresses of a page from a shared file needs
to have identical bits in the range 2^12 to 2^18.

Signed-off-by: Martin Schwidefsky

s390/simd: clear vector register pointer on fork/clone

2014-12-08T08:42:35+00:00

The copy_thread function fails to reset the p->thread.vxrs pointer.
This causes the child to use the same vector register save area,
causing both data corruptions and multiple frees of the memory for
the save area after the tasks sharing the save area terminate.

Signed-off-by: Martin Schwidefsky

s390/kprobes: make use of NOKPROBE_SYMBOL()

2014-10-27T12:27:28+00:00

Use NOKPROBE_SYMBOL() instead of __kprobes annotation.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/idle: consolidate idle functions and definitions

2014-10-09T07:14:03+00:00

Move the C functions and definitions related to the idle state handling
to arch/s390/include/asm/idle.h and arch/s390/kernel/idle.c. The function
s390_get_idle_time is renamed to arch_cpu_idle_time and vtime_stop_cpu to
enabled_wait.

Signed-off-by: Martin Schwidefsky

s390: split TIF bits into CIF, PIF and TIF bits

2014-05-20T06:58:47+00:00

The oi and ni instructions used in entry[64].S to set and clear bits
in the thread-flags are not guaranteed to be atomic in regard to other
CPUs. Split the TIF bits into CPU, pt_regs and thread-info specific
bits. Updates on the TIF bits are done with atomic instructions,
updates on CPU and pt_regs bits are done with non-atomic instructions.

Signed-off-by: Martin Schwidefsky

s390/mm: optimize randomize_et_dyn for !PF_RANDOMIZE

2013-12-18T16:36:38+00:00

Skip the call to brk_rnd() if the PF_RANDOMIZE flag is not set for
the process. This avoids the costly get_random_int() call. Modify
arch_randomize_brk() as well to make it look like randomize_et_dyn().

Signed-off-by: Martin Schwidefsky

s390: fix save and restore of the floating-point-control register

2013-10-24T15:17:11+00:00

The FPC_VALID_MASK has been used to check the validity of the value
to be loaded into the floating-point-control register. With the
introduction of the floating-point extension facility and the
decimal-floating-point additional bits have been defined which need
to be checked in a non straight forward way. So far these bits have
been ignored which can cause an incorrect results for decimal-
floating-point operations, e.g. an incorrect rounding mode to be
set after signal return.

The static check with the FPC_VALID_MASK is replaced with a trial
load of the floating-point-control value, see test_fp_ctl.

In addition an information leak with the padding word between the
floating-point-control word and the floating-point registers in
the s390_fp_regs is fixed.

Reported-by: Heiko Carstens 
Reviewed-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky