linux.git/arch/s390/kernel/head.S, branch v4.13

s390/facilities: get rid of ASSEMBLY in facility header file

2017-03-22T07:29:18+00:00

There is no need for the __ASSEMBLY__ ifdefery anymore since the
architecture level set code that deals with facility bits was
converted to C in the meantime.

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

s390/thread_info: get rid of THREAD_ORDER define

2016-11-23T15:02:21+00:00

We have the s390 specific THREAD_ORDER define and the THREAD_SIZE_ORDER
define which is also used in common code. Both have exactly the same
semantics. Therefore get rid of THREAD_ORDER and always use
THREAD_SIZE_ORDER instead.

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

s390: clarify compressed image code path

2016-08-08T13:41:31+00:00

The way the decompressor is hooked into the start-up code is rather
subtle, with a mix of multiply-defined symbols and hardcoded address
literals. Add some comments at the junction points to clarify how it
works.

Signed-off-by: Sascha Silbe 
Signed-off-by: Martin Schwidefsky

s390/als: convert architecture level set code to C

2016-07-31T09:27:58+00:00

There is no reason to have this code in assembly language. Therefore
convert it to C.

Note that this code needs special treatment: it is called very early
and one of the side effects is that e.g. the bss section is not
cleared. Therefore the preferred way for static variables is to put
them on the stack which has a size of 16KB.

There is no functional change with this patch.

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

s390/facilities: make use of generated facility list

2015-12-18T13:59:21+00:00

Change head.S to make use of the generated facility list.

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

s390/facilities: always use lowcore's stfle field for storing facility bits

2015-12-18T13:59:19+00:00

head.s contains an stfle instruction which stores it result at the
storage location that is assigned to the stfl instruction.

This is currently no problem, since we only care about one double
word. However if the number of double words in the ALS bitfield grows
the current code is not very stable.

E.g. before issuing the stfle command the memory to which it stores
must be cleared, since the instruction may or may not clear memory
contents where no bits are set.

In order to simplify the code a bit always use the storage location
that we reserved for the stfle result.

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

s390/facilities: use stfl mnemonic instead of insn magic

2015-12-18T13:59:18+00:00

Now that 31 bit support is gone, the assembler always knows about the
stfl instruction. Therefore lets use a readable mnemonic.  Also remove
the not needed extable entry for the inline assembly and fix the
output constraint.

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

s390: remove SALIPL loader

2015-11-16T11:51:11+00:00

There is no known user, therefore remove the code.

Acked-by: Rob Van Der Heij 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/head: fix error message on unsupported hardware

2015-11-09T08:10:47+00:00

startup calls the C function _sclp_print_early() if the machine we're
running on is not supported by the kernel. sclp.c is getting built
with -m64, so _sclp_print_early() expects the zSeries ELF ABI to be
used.

We previously called _sclp_print_early() using the S/390 ELF ABI, with
a stack frame size of 96 bytes and while being in 31-bit address
mode. This caused _sclp_wait_int() (called indirectly from
_sclp_print_early()) to jump to an undefined address. While
_sclp_wait_int() contained some code to deal with being called in
31-bit addressing mode, it didn't quite work. While fixing this is
possible, the code would still only work by chance and could break any
time.

Ensure compliance with the zSeries ELF ABI by switching to 64-bit
addressing mode early and using a minimum stack frame size of 160
bytes.

Signed-off-by: Sascha Silbe 
Acked-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/facilities: remove transactional-execution bits

2015-08-19T08:03:34+00:00

Remove the two facility bits

50 - constrained transactional-execution facility
74 - transactional-execution facility

from the required facilities if the kernel is built with -march=zEC12.

E.g. z/VM 6.3 doesn't virtualize the TX facility yet. Therefore a kernel
built with -march=zEC12 and ipl'ed on a zEC12 machine as a z/VM 6.3 guest
will emit a message about the missing facilities and stop working.

The kernel however doesn't make use of the TX facility, therefore remove
the two TX related facility bits and fix this unpleasant behavior.

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