linux-stable.git/arch/s390/kernel/entry.h, branch linux-4.4.y

s390/udelay: make udelay have busy loop semantics

2015-10-14T12:32:13+00:00

When using systemtap it was observed that our udelay implementation is
rather suboptimal if being called from a kprobe handler installed by
systemtap.

The problem observed when a kprobe was installed on lock_acquired().
When the probe was hit the kprobe handler did call udelay, which set
up an (internal) timer and reenabled interrupts (only the clock comparator
interrupt) and waited for the interrupt.
This is an optimization to avoid that the cpu is busy looping while waiting
that enough time passes. The problem is that the interrupt handler still
does call irq_enter()/irq_exit() which then again can lead to a deadlock,
since some accounting functions may take locks as well.

If one of these locks is the same, which caused lock_acquired() to be
called, we have a nice deadlock.

This patch reworks the udelay code for the interrupts disabled case to
immediately leave the low level interrupt handler when the clock
comparator interrupt happens. That way no C code is being called and the
deadlock cannot happen anymore.

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

s390/fpu: always enable the vector facility if it is available

2015-10-14T12:32:08+00:00

If the kernel detects that the s390 hardware supports the vector
facility, it is enabled by default at an early stage.  To force
it off, use the novx kernel parameter.  Note that there is a small
time window, where the vector facility is enabled before it is
forced to be off.

With enabling the vector facility by default, the FPU save and
restore functions can be improved.  They do not longer require
to manage expensive control register updates to enable or disable
the vector enablement control for particular processes.

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

s390/signal: add sys_sigreturn and sys_rt_sigreturn declarations

2015-01-08T09:02:49+00:00

Get rid of sparse warnings like this one:
arch/s390/kernel/signal.c:244:1:
  warning: symbol 'sys_sigreturn' was not declared. Should it be static?

Signed-off-by: Heiko Carstens

s390/kernel: add system calls for PCI memory access

2014-11-19T08:46:43+00:00

Add the new __NR_s390_pci_mmio_write and __NR_s390_pci_mmio_read
system calls to allow user space applications to access device PCI I/O
memory pages on s390x platform.

[ Martin Schwidefsky: some code beautification ]

Signed-off-by: Alexey Ishchuk 
Signed-off-by: Martin Schwidefsky

s390: add support for vector extension

2014-10-09T07:14:13+00:00

The vector extension introduces 32 128-bit vector registers and a set of
instruction to operate on the vector registers.

The kernel can control the use of vector registers for the problem state
program with a bit in control register 0. Once enabled for a process the
kernel needs to retain the content of the vector registers on context
switch. The signal frame is extended to include the vector registers.
Two new register sets NT_S390_VXRS_LOW and NT_S390_VXRS_HIGH are added
to the regset interface for the debugger and core dumps.

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/uprobes: architecture backend for uprobes

2014-09-25T08:52:17+00:00

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

s390: Use get_signal() signal_setup_done()

2014-08-06T11:03:10+00:00

Use the more generic functions get_signal() signal_setup_done()
for signal delivery.

Signed-off-by: Richard Weinberger

s390/compat: get rid of compat wrapper assembly code

2014-03-06T15:30:48+00:00

Now that all compat syscalls have been converted to use the
COMPAT_SYSCALL_DEFINE macros, we don't need to compat syscall
wrapper assembly code anymore.
So remove it and fix up the system call table accordingly.

Signed-off-by: Heiko Carstens

s390/compat: convert system call wrappers to C part 15

2014-03-04T08:05:46+00:00

Signed-off-by: Heiko Carstens