linux.git/arch/s390/include/asm/setup.h, branch v3.15

s390/mm,tlb: optimize TLB flushing for zEC12

2014-04-03T12:31:00+00:00

The zEC12 machines introduced the local-clearing control for the IDTE
and IPTE instruction. If the control is set only the TLB of the local
CPU is cleared of entries, either all entries of a single address space
for IDTE, or the entry for a single page-table entry for IPTE.
Without the local-clearing control the TLB flush is broadcasted to all
CPUs in the configuration, which is expensive.

The reset of the bit mask of the CPUs that need flushing after a
non-local IDTE is tricky. As TLB entries for an address space remain
in the TLB even if the address space is detached a new bit field is
required to keep track of attached CPUs vs. CPUs in the need of a
flush. After a non-local flush with IDTE the bit-field of attached CPUs
is copied to the bit-field of CPUs in need of a flush. The ordering
of operations on cpu_attach_mask, attach_count and mm_cpumask(mm) is
such that an underindication in mm_cpumask(mm) is prevented but an
overindication in mm_cpumask(mm) is possible.

Signed-off-by: Martin Schwidefsky

s390/setup: get rid of MACHINE_HAS_MVCOS machine flag

2014-02-21T07:50:15+00:00

MACHINE_HAS_MVCOS is used exactly once when the machine is brought up.
There is no need to cache the flag in the machine_flags.

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

s390/sclp: Determine HSA size dynamically for zfcpdump

2013-11-15T13:08:40+00:00

Currently we have hardcoded the HSA size to 32 MiB. With this patch the
HSA size is determined dynamically via SCLP in early.c.

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

s390/uaccess: always run the kernel in home space

2013-10-24T15:16:57+00:00

Simplify the uaccess code by removing the user_mode=home option.
The kernel will now always run in the home space mode.

Signed-off-by: Martin Schwidefsky

s390/mem_detect: remove artificial kdump memory types

2013-05-03T12:21:15+00:00

Simplify the memory detection code a bit by removing the CHUNK_OLDMEM
and CHUNK_CRASHK memory types.
They are not needed. Everything that is needed is a mechanism to
insert holes into the detected memory.

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

s390/mem_detect: limit memory detection loop to "mem=" parameter

2013-05-02T13:50:26+00:00

The current memory detection loop will detect all present memory of
a machine. This is true even if the user specified the "mem=" parameter
on the kernel command line.
This can be a problem since the memory detection may cause a fully
populated host page table for the guest, even for those parts of the
memory that the guest will never use afterwards.

So fix this and only detect memory up to a user supplied "mem=" limit
if specified.

Reported-by: Michael Johanssen 
Reviewed-by: Michael Holzheu 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390: get rid of odd global real_memory_size

2013-05-02T13:50:25+00:00

The variable real_memory_size has odd semantics and has been used in
a broken way by e.g. the old kvm code.
Therefore get rid of it before anybody else makes use of it.

Reviewed-by: Michael Holzheu 
Signed-off-by: Heiko Carstens 
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

s390/mm: implement software dirty bits

2013-02-14T14:55:23+00:00

The s390 architecture is unique in respect to dirty page detection,
it uses the change bit in the per-page storage key to track page
modifications. All other architectures track dirty bits by means
of page table entries. This property of s390 has caused numerous
problems in the past, e.g. see git commit ef5d437f71afdf4a
"mm: fix XFS oops due to dirty pages without buffers on s390".

To avoid future issues in regard to per-page dirty bits convert
s390 to a fault based software dirty bit detection mechanism. All
user page table entries which are marked as clean will be hardware
read-only, even if the pte is supposed to be writable. A write by
the user process will trigger a protection fault which will cause
the user pte to be marked as dirty and the hardware read-only bit
is removed.

With this change the dirty bit in the storage key is irrelevant
for Linux as a host, but the storage key is still required for
KVM guests. The effect is that page_test_and_clear_dirty and the
related code can be removed. The referenced bit in the storage
key is still used by the page_test_and_clear_young primitive to
provide page age information.

For page cache pages of mappings with mapping_cap_account_dirty
there will not be any change in behavior as the dirty bit tracking
already uses read-only ptes to control the amount of dirty pages.
Only for swap cache pages and pages of mappings without
mapping_cap_account_dirty there can be additional protection faults.
To avoid an excessive number of additional faults the mk_pte
primitive checks for PageDirty if the pgprot value allows for writes
and pre-dirties the pte. That avoids all additional faults for
tmpfs and shmem pages until these pages are added to the swap cache.

Signed-off-by: Martin Schwidefsky

Merge tag 'disintegrate-s390-20121009' of

2012-10-09T12:18:10+00:00

git://git.infradead.org/users/dhowells/linux-headers

Pull UAPI patchset from David Howells:
 "Can you merge the following branch into the s390 tree please.
  This is to complete part of the UAPI disintegration for which the
  preparatory patches were pulled recently."

Conflicts:
	arch/s390/include/asm/chpid.h