linux-stable.git/arch/s390/kernel/entry64.S, branch linux-3.7.y

s390/kvm: Fix address space mixup

2013-01-17T16:45:44+00:00

commit ce6a04ac1b759beafc88dbc443ae5da867579eeb upstream.

I was chasing down a bug of random validity intercepts on s390.
(guest prefix page not mapped in the host virtual aspace). Turns out
that the problem was a wrong address space control element. The
cause was quite complex:

During paging activity a DAT protection during SIE caused a program
interrupt. Normally, the sie retry loop tries to catch all
interrupts during and shortly before sie to rerun the setup. The
problem is now that protection causes a suppressing program interrupt,
causing the PSW to point to the instruction AFTER SIE in case of DAT
protection. This confused the logic of the retry loop to not trigger,
instead we jumped directly back to SIE after return from
the program  interrupt. (the protection fault handler itself did
a rewind of the psw). This usually works quite well, but:

If now the protection fault handler has to wait, another program
might be scheduled in. Later on the sie process will be schedules
in again. In that case the content of CR1 (primary address space)
will be wrong because switch_to will put the user space ASCE into CR1
and not the guest ASCE.

In addition the program parameter is also wrong for every protection
fault of a guest, since we dont issue the SPP instruction.

So lets also check for PSW == instruction after SIE in the program
check handler. Instead of expensively checking all program
interruption codes that might be suppressing we assume that a program
interrupt pointing after SIE was always a program interrupt in SIE.
(Otherwise we have a kernel bug anyway).

We also have to compensate the rewinding, since the C-level handlers
will do that. Therefore we need to add a nop with the same length
as SIE before the sie_loop.

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

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

2012-10-10T10:48:33+00:00

Pull second s390 update from Martin Schwidefsky:
 "The big thing in this pull request is the UAPI patch from David, and
  worth mentioning is the page table dumper.  The rest are small
  improvements and bug fixes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/entry: fix svc number for TIF_SYSCALL system call restart
  s390/mm,vmem: fix vmem_add_mem()/vmem_remove_range()
  s390/vmalloc: have separate modules area
  s390/zcrypt: remove duplicated include from zcrypt_pcixcc.c
  s390/css_chars: remove superfluous ifdef
  s390/chsc: make headers usable
  s390/mm: let kernel text section always begin at 1MB
  s390/mm: fix mapping of read-only kernel text section
  s390/mm: add page table dumper
  s390: add support to start the kernel in 64 bit mode.
  s390/mm,pageattr: remove superfluous EXPORT_SYMBOLs
  s390/mm,pageattr: add more page table walk sanity checks
  s390/mm: fix pmd_huge() usage for kernel mapping
  s390/dcssblk: cleanup device attribute usage
  s390/mm: use pfmf instruction to initialize storage keys
  s390/facilities: cleanup PFMF and HPAGE machine facility detection
  UAPI: (Scripted) Disintegrate arch/s390/include/asm

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

2012-10-10T03:02:25+00:00

Pull generic execve() changes from Al Viro:
 "This introduces the generic kernel_thread() and kernel_execve()
  functions, and switches x86, arm, alpha, um and s390 over to them."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
  s390: convert to generic kernel_execve()
  s390: switch to generic kernel_thread()
  s390: fold kernel_thread_helper() into ret_from_fork()
  s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
  um: switch to generic kernel_thread()
  x86, um/x86: switch to generic sys_execve and kernel_execve
  x86: split ret_from_fork
  alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  alpha: switch to generic kernel_thread()
  alpha: switch to generic sys_execve()
  arm: get rid of execve wrapper, switch to generic execve() implementation
  arm: optimized current_pt_regs()
  arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
  generic sys_execve()
  generic kernel_execve()
  new helper: current_pt_regs()
  preparation for generic kernel_thread()
  um: kill thread->forking
  um: let signal_delivered() do SIGTRAP on singlestepping into handler
  ...

s390/entry: fix svc number for TIF_SYSCALL system call restart

2012-10-09T12:17:02+00:00

The load of the svc number in the TIF_SYSCALL restart path needs to be
done with an instruction that loads all 64 bits of %r1, 'lh' only loads
32 bits. If the upper half of %r1 is not zero and has the msb set,
entry64.S will try to execute an svc with a really large number.
What will be in the upper half of %r1 depends on the code generated by
gcc for the functions on the do_signal() callchain.

Signed-off-by: Martin Schwidefsky

s390: convert to generic kernel_execve()

2012-10-01T03:03:04+00:00

same situation as with alpha and arm - only massage needed

Signed-off-by: Al Viro

s390: fold kernel_thread_helper() into ret_from_fork()

2012-10-01T03:03:03+00:00

... and don't bother with syscall return path in case of kernel
threads.

Signed-off-by: Al Viro

s390: fold execve_tail() into start_thread(), convert to generic sys_execve()

2012-10-01T03:03:02+00:00

Signed-off-by: Al Viro

s390/exceptions: switch to relative exception table entries

2012-09-26T13:45:10+00:00

This is the s390 port of 70627654 "x86, extable: Switch to relative
exception table entries".
Reduces the size of our exception tables by 50% on 64 bit builds.

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

s390: add support for transactional memory

2012-09-26T13:45:02+00:00

Allow user-space processes to use transactional execution (TX).
If the TX facility is available user space programs can use
transactions for fine-grained serialization based on the data
objects that are referenced during a transaction. This is
useful for lockless data structures and speculative compiler
optimizations.

Signed-off-by: Martin Schwidefsky

s390/vtimer: rework virtual timer interface

2012-07-20T09:15:08+00:00

The current virtual timer interface is inherently per-cpu and hard to
use. The sole user of the interface is appldata which uses it to execute
a function after a specific amount of cputime has been used over all cpus.

Rework the virtual timer interface to hook into the cputime accounting.
This makes the interface independent from the CPU timer interrupts, and
makes the virtual timers global as opposed to per-cpu.
Overall the code is greatly simplified. The downside is that the accuracy
is not as good as the original implementation, but it is still good enough
for appldata.

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