linux-toradex.git/arch/s390/kernel/entry64.S, branch v3.10.61

s390: fix system call restart after inferior call

2013-10-13T23:08:34+00:00

commit dbbfe487e5f3fc00c9fe5207d63309859704d12f upstream.

Git commit 616498813b11ffef "s390: system call path micro optimization"
introduced a regression in regard to system call restarting and inferior
function calls via the ptrace interface. The pointer to the system call
table needs to be loaded in sysc_sigpending if do_signal returns with
TIF_SYSCALl set after it restored a system call context.

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

s390: system call path micro optimization

2013-04-26T07:07:05+00:00

Add a pointer to the system call table to the thread_info structure.
The TIF_31BIT bit is set or cleared by SET_PERSONALITY exactly once
for the lifetime of a process. With the pointer to the correct system
call table in thread_info the system call code in entry64.S path can
drop the check for TIF_31BIT which saves a couple of instructions.

Signed-off-by: Martin Schwidefsky

s390: lowcore stack pointer offsets

2013-04-26T07:07:01+00:00

Store the stack pointers in the lowcore for the kernel stack, the async
stack and the panic stack with the offset required for the first user.
This avoids an unnecessary add instruction on the system call path.

Signed-off-by: Martin Schwidefsky

s390: critical section cleanup vs. machine checks

2013-03-05T09:21:35+00:00

The current machine check code uses the registers stored by the machine
in the lowcore at __LC_GPREGS_SAVE_AREA as the registers of the interrupted
context. The registers 0-7 of a user process can get clobbered if a machine
checks interrupts the execution of a critical section in entry[64].S.

The reason is that the critical section cleanup code may need to modify
the PSW and the registers for the previous context to get to the end of a
critical section. If registers 0-7 have to be replaced the relevant copy
will be in the registers, which invalidates the copy in the lowcore. The
machine check handler needs to explicitly store registers 0-7 to the stack.

Cc: stable@vger.kernel.org
Signed-off-by: Martin Schwidefsky

s390/cleanup: rename SPP to LPP

2013-02-14T14:55:24+00:00

The set-program-parameter (SPP) instruction has been renamed to
load-program-parameter (LPP) (see SA23-2260).  Reflect this change
and rename all macro/instruction references.

Also remove the duplicate SPP/LPP entry in the kernel disassembler
instruction list.

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

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

2012-12-13T22:20:19+00:00

Pull s390 update from Martin Schwidefsky:
 "Add support to generate code for the latest machine zEC12, MOD and XOR
  instruction support for the BPF jit compiler, the dasd safe offline
  feature and the big one: the s390 architecture gets PCI support!!
  Right before the world ends on the 21st ;-)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits)
  s390/qdio: rename the misleading PCI flag of qdio devices
  s390/pci: remove obsolete email addresses
  s390/pci: speed up __iowrite64_copy by using pci store block insn
  s390/pci: enable NEED_DMA_MAP_STATE
  s390/pci: no msleep in potential IRQ context
  s390/pci: fix potential NULL pointer dereference in dma_free_seg_table()
  s390/pci: use kmem_cache_zalloc instead of kmem_cache_alloc/memset
  s390/bpf,jit: add support for XOR instruction
  s390/bpf,jit: add support MOD instruction
  s390/cio: fix pgid reserved check
  vga: compile fix, disable vga for s390
  s390/pci: add PCI Kconfig options
  s390/pci: s390 specific PCI sysfs attributes
  s390/pci: PCI hotplug support via SCLP
  s390/pci: CHSC PCI support for error and availability events
  s390/pci: DMA support
  s390/pci: PCI adapter interrupts for MSI/MSI-X
  s390/bitops: find leftmost bit instruction support
  s390/pci: CLP interface
  s390/pci: base support
  ...

s390/kvm: Fix address space mixup

2012-11-23T10:14:34+00:00

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: stable@vger.kernel.org
CC: Heiko Carstens

s390/ptrace: race of single stepping vs signal delivery

2012-11-23T10:14:33+00:00

The current single step code is racy in regard to concurrent delivery
of signals. If a signal is delivered after a PER program check occurred
but before the TIF_PER_TRAP bit has been checked in entry[64].S the code
clears TIF_PER_TRAP and then calls do_signal. This is wrong, if the
instruction completed (or has been suppressed) a SIGTRAP should be
delivered to the debugger in any case. Only if the instruction has been
nullified the SIGTRAP may not be send.

The new logic always sets TIF_PER_TRAP if the program check indicates PER
tracing but removes it again for all program checks that are nullifying.
The effect is that for each change in the PSW address we now get a
single SIGTRAP.

Reported-by: Andreas Arnez 
Signed-off-by: Martin Schwidefsky

s390/traps: preinitialize program check table

2012-11-23T10:14:25+00:00

Preinitialize the program check table, so we can put it into the
read-only data section.
Also use only four byte entries for the table, since each program
check handler resides within the first 2GB. Therefore this reduces
the size of the table by 50% on 64 bit builds.

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

s390: switch to saner kernel_execve() semantics

2012-10-29T14:54:37+00:00

Acked-by: Martin Schwidefsky 
Signed-off-by: Al Viro