linux-stable.git/arch/s390/include/asm/processor.h, branch linux-4.7.y

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

2016-05-18T19:17:16+00:00

Pull s390 updates from Martin Schwidefsky:
 "The s390 patches for the 4.7 merge window have the usual bug fixes and
  cleanups, and the following new features:

   - An interface for dasd driver to query if a volume is online to
     another operating system

   - A new ioctl for the dasd driver to verify the format for a range of
     tracks

   - Following the example of x86 the struct fpu is now allocated with
     the task_struct

   - The 'report_error' interface for the PCI bus to send an
     adapter-error notification from user space to the service element
     of the machine"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (29 commits)
  s390/vmem: remove unused function parameter
  s390/vmem: fix identity mapping
  s390: add missing include statements
  s390: add missing declarations
  s390: make couple of variables and functions static
  s390/cache: remove superfluous locking
  s390/cpuinfo: simplify locking and skip offline cpus early
  s390/3270: hangup the 3270 tty after a disconnect
  s390/3270: handle reconnect of a tty with a different size
  s390/3270: avoid endless I/O loop with disconnected 3270 terminals
  s390/3270: fix garbled output on 3270 tty view
  s390/3270: fix view reference counting
  s390/3270: add missing tty_kref_put
  s390/dumpstack: implement and use return_address()
  s390/cpum_sf: Remove superfluous SMP function call
  s390/cpum_cf: Remove superfluous SMP function call
  s390/Kconfig: make z196 the default processor type
  s390/sclp: avoid compile warning in sclp_pci_report
  s390/fpu: allocate 'struct fpu' with the task_struct
  s390/crypto: cleanup and move the header with the cpacf definitions
  ...

s390/fpu: allocate 'struct fpu' with the task_struct

2016-04-21T07:51:15+00:00

Analog to git commit 0c8c0f03e3a292e031596484275c14cf39c0ab7a
"x86/fpu, sched: Dynamically allocate 'struct fpu'"
move the struct fpu to the end of the struct thread_struct,
set CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and add the
setup_task_size() function to calculate the correct size
fo the task struct.

For the performance_defconfig this increases the size of
struct task_struct from 7424 bytes to 7936 bytes (MACHINE_HAS_VX==1)
or 7552 bytes (MACHINE_HAS_VX==0). The dynamic allocation of the
struct fpu is removed. The slab cache uses an 8KB block for the
task struct in all cases, there is enough room for the struct fpu.
For MACHINE_HAS_VX==1 each task now needs 512 bytes less memory.

Signed-off-by: Martin Schwidefsky

s390/mm: fix asce_bits handling with dynamic pagetable levels

2016-04-21T07:50:09+00:00

There is a race with multi-threaded applications between context switch and
pagetable upgrade. In switch_mm() a new user_asce is built from mm->pgd and
mm->context.asce_bits, w/o holding any locks. A concurrent mmap with a
pagetable upgrade on another thread in crst_table_upgrade() could already
have set new asce_bits, but not yet the new mm->pgd. This would result in a
corrupt user_asce in switch_mm(), and eventually in a kernel panic from a
translation exception.

Fix this by storing the complete asce instead of just the asce_bits, which
can then be read atomically from switch_mm(), so that it either sees the
old value or the new value, but no mixture. Both cases are OK. Having the
old value would result in a page fault on access to the higher level memory,
but the fault handler would see the new mm->pgd, if it was a valid access
after the mmap on the other thread has completed. So as worst-case scenario
we would have a page fault loop for the racing thread until the next time
slice.

Also remove dead code and simplify the upgrade/downgrade path, there are no
upgrades from 2 levels, and only downgrades from 3 levels for compat tasks.
There are also no concurrent upgrades, because the mmap_sem is held with
down_write() in do_mmap, so the flush and table checks during upgrade can
be removed.

Reported-by: Michael Munday 
Reviewed-by: Martin Schwidefsky 
Signed-off-by: Gerald Schaefer 
Signed-off-by: Martin Schwidefsky

s390/dumpstack: merge all four stack tracers

2016-02-23T07:56:20+00:00

We have four different stack tracers of which three had bugs. So it's
time to merge them to a single stack tracer which allows to specify a
call back function which will be called for each step.

This patch changes behavior a bit:

- the "nosched" and "in_sched_functions" check within
  save_stack_trace_tsk did work only for the last stack frame within a
  context. Now it considers the check for each stack frame like it
  should.

- both the oprofile variant and the perf_events variant did save a
  return address twice if a zero back chain was detected, which
  indicates an interrupt frame. The new dump_trace function will call
  the oprofile and perf_events backends with the psw address that is
  contained within the corresponding pt_regs structure instead.

- the original show_trace and save_context_stack functions did already
  use the psw address of the pt_regs structure if a zero back chain
  was detected. However now we ignore the psw address if it is a user
  space address. After all we trace the kernel stack and not the user
  space stack. This way we also get rid of the garbage user space
  address in case of warnings and / or panic call traces.

So this should make life easier since now there is only one stack
tracer left which we can break.

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

s390: add current_stack_pointer() helper function

2016-02-23T07:56:18+00:00

Implement current_stack_pointer() helper function and use it
everywhere, instead of having several different inline assembly
variants.

Signed-off-by: Heiko Carstens 
Tested-by: Peter Oberparleiter 
Signed-off-by: Martin Schwidefsky

s390: remove all usages of PSW_ADDR_AMODE

2016-01-19T11:14:02+00:00

This is a leftover from the 31 bit area. For CONFIG_64BIT the usual
operation "y = x | PSW_ADDR_AMODE" is a nop. Therefore remove all
usages of PSW_ADDR_AMODE and make the code a bit less confusing.

Signed-off-by: Heiko Carstens 
Reviewed-by: David Hildenbrand

s390: rename struct _lowcore to struct lowcore

2016-01-11T11:27:15+00:00

Finally get rid of the leading underscore. I tried this already two or
three years ago, however Michael Holzheu objected since this would
break the crash utility (again).

However Michael integrated support for the new name into the crash
utility back then, so it doesn't break if the name will be changed
now.  So finally get rid of the ever confusing leading underscore.

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

s390/spinlock: do not yield to a CPU in udelay/mdelay

2015-11-27T08:24:18+00:00

It does not make sense to try to relinquish the time slice with diag 0x9c
to a CPU in a state that does not allow to schedule the CPU. The scenario
where this can happen is a CPU waiting in udelay/mdelay while holding a
spin-lock.

Add a CIF bit to tag a CPU in enabled wait and use it to detect that the
yield of a CPU will not be successful and skip the diagnose call.

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

s390: remove runtime instrumentation interrupts

2015-11-03T13:40:51+00:00

The external interrupts for runtime instrumentation buffer-full
and runtime instrumentation halted are unused and have no current
user. Remove the support and ignore the second parameter of the
s390_runtime_instr system call from now on.

Signed-off-by: Martin Schwidefsky

s390: don't store registers on disabled wait anymore

2015-10-27T08:33:48+00:00

The current disabled wait code stores register contents into their
save areas, however it is (at least) missing the new vector registers.

Given the fact that the whole exercise seems to be rather pointless
simply don't save any registers anymore.

In a "live" system it is always possible to inspect register contents,
and in case of a dump the register contents will be stored by the
dump mechanism.

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