linux.git/arch/s390/include, branch v4.17

s390: extend expoline to BC instructions

2018-05-07T19:12:42+00:00

The BPF JIT uses a 'b (%r)' instruction in the definition
of the sk_load_word and sk_load_half functions.

Add support for branch-on-condition instructions contained in the
thunk code of an expoline.

Signed-off-by: Martin Schwidefsky

s390/ftrace: use expoline for indirect branches

2018-05-07T19:12:38+00:00

The return from the ftrace_stub, _mcount, ftrace_caller and
return_to_handler functions is done with "br %r14" and "br %r1".
These are indirect branches as well and need to use execute
trampolines for CONFIG_EXPOLINE=y.

The ftrace_caller function is a special case as it returns to the
start of a function and may only use %r0 and %r1. For a pre z10
machine the standard execute trampoline uses a LARL + EX to do
this, but this requires *two* registers in the range %r1..%r15.
To get around this the 'br %r1' located in the lowcore is used,
then the EX instruction does not need an address register.
But the lowcore trick may only be used for pre z14 machines,
with noexec=on the mapping for the first page may not contain
instructions. The solution for that is an ALTERNATIVE in the
expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to
EXRL, this relies on the fact that a machine that supports
noexec=on has EXRL as well.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Martin Schwidefsky

s390: move expoline assembler macros to a header

2018-05-07T07:07:32+00:00

To be able to use the expoline branches in different assembler
files move the associated macros from entry.S to a new header
nospec-insn.h.

While we are at it make the macros a bit nicer to use.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Martin Schwidefsky

s390/kexec_file: add declaration of purgatory related globals

2018-04-27T04:51:31+00:00

Fix the following sparse complaints:

arch/s390/purgatory/purgatory.c:18:5: warning: symbol 'kernel_entry' was not declared. Should it be static?
arch/s390/purgatory/purgatory.c:19:5: warning: symbol 'kernel_type' was not declared. Should it be static?
arch/s390/purgatory/purgatory.c:21:5: warning: symbol 'crash_start' was not declared. Should it be static?
arch/s390/purgatory/purgatory.c:22:5: warning: symbol 'crash_size' was not declared. Should it be static?

Signed-off-by: Sebastian Ott 
Signed-off-by: Martin Schwidefsky

s390: update sampling tag after task pid change

2018-04-23T05:57:17+00:00

In a multi-threaded program any thread can call execve(). If this
is not done by the thread group leader, the de_thread() function
replaces the pid of the task that calls execve() with the pid of
thread group leader. If the task reaches user space again without
going over __switch_to() the sampling tag is still set to the old
pid.

Define the arch_setup_new_exec function to verify the task pid
and udpate the tag with LPP if it has changed.

Signed-off-by: Martin Schwidefsky

s390/signal: cleanup uapi struct sigaction

2018-04-17T08:36:12+00:00

The struct sigaction for user space in arch/s390/include/uapi/asm/signal.h
is ill defined. The kernel uses two structures 'struct sigaction' and
'struct old_sigaction', the correlation in the kernel for both 31 and
64 bit is as follows

    sys_sigaction -> struct old_sigaction
    sys_rt_sigaction -> struct sigaction

The correlation of the (single) uapi definition for 'struct sigaction'
under '#ifndef __KERNEL__':

    31-bit: sys_sigaction -> uapi struct sigaction
    31-bit: sys_rt_sigaction -> no structure available

    64-bit: sys_sigaction -> no structure available
    64-bit: sys_rt_sigaction -> uapi struct sigaction

This is quite confusing. To make it a bit less confusing make the
uapi definition of 'struct sigaction' usable for sys_rt_sigaction for
both 31-bit and 64-bit.

Signed-off-by: Martin Schwidefsky

s390/kexec_file: Add ELF loader

2018-04-16T07:10:23+00:00

Add an ELF loader for kexec_file. The main task here is to do proper sanity
checks on the ELF file. Basically all other functionality was already
implemented for the image loader.

Signed-off-by: Philipp Rudo 
Signed-off-by: Martin Schwidefsky

s390/kexec_file: Add image loader

2018-04-16T07:10:22+00:00

Add an image loader for kexec_file_load. For simplicity first skip crash
support. The functions defined in machine_kexec_file will later be shared
with the ELF loader.

Signed-off-by: Philipp Rudo 
Reviewed-by: Martin Schwidefsky 
Signed-off-by: Martin Schwidefsky

s390/kexec_file: Add purgatory

2018-04-16T07:10:22+00:00

The common code expects the architecture to have a purgatory that runs
between the two kernels. Add it now. For simplicity first skip crash
support.

Signed-off-by: Philipp Rudo 
Signed-off-by: Martin Schwidefsky

s390/kexec_file: Prepare setup.h for kexec_file_load

2018-04-16T07:10:21+00:00

kexec_file_load needs to prepare the new kernels before they are loaded.
For that it has to know the offsets in head.S, e.g. to register the new
command line. Unfortunately there are no macros right now defining those
offsets. Define them now.

Signed-off-by: Philipp Rudo 
Signed-off-by: Martin Schwidefsky