linux.git/arch/s390/kernel/entry.S, branch v3.11

s390/irq: store interrupt information in pt_regs

2013-06-26T19:10:23+00:00

Copy the interrupt parameters from the lowcore to the pt_regs structure
in entry[64].S and reduce the arguments of the low level interrupt handler
to the pt_regs pointer only. In addition move the test-pending-interrupt
loop from do_IRQ to entry[64].S to make sure that interrupt information
is always delivered via pt_regs.

Signed-off-by: Martin Schwidefsky

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

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/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: switch to saner kernel_execve() semantics

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

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

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