s390/fpu: remove TIF_FPU

TIF_FPU is unused - remove it.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/fpu: convert FPU CIF flag to regular TIF flag

The FPU state, as represented by the CIF_FPU flag reflects the FPU state of
a task, not the CPU it is running on. Therefore convert the flag to a
regular TIF flag.

This removes the magic in switch_to() where a save_fpu_regs() call for the
currently (previous) running task sets the per-cpu CIF_FPU flag, which is
required to restore FPU register contents of the next task, when it returns
to user space.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

thread_info: move function declarations to linux/thread_info.h

There are a few __weak functions in kernel/fork.c, which architectures
can override. If there is no prototype, the compiler warns about them:

kernel/fork.c:164:13: error: no previous prototype for 'arch_release_task_struct' [-Werror=missing-prototypes]
kernel/fork.c:991:20: error: no previous prototype for 'arch_task_cache_init' [-Werror=missing-prototypes]
kernel/fork.c:1086:12: error: no previous prototype for 'arch_dup_task_struct' [-Werror=missing-prototypes]

There are already prototypes in a number of architecture specific headers
that have addressed those warnings before, but it's much better to have
these in a single place so the warning no longer shows up anywhere.

Link: https://lkml.kernel.org/r/20230517131102.934196-14-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

s390/stack: use STACK_INIT_OFFSET where possible

Make STACK_INIT_OFFSET also available for assembler code, and
use it everywhere instead of open-coding it at several places.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/bp: remove TIF_ISOLATE_BP

TIF_ISOLATE_BP is unused since it was introduced with commit 6b73044b2b00
("s390: run user space and KVM guests with modified branch prediction").
Given that there is no use case remove it again.

Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390: add CPU field to struct thread_info

The CPU field will be moved back into thread_info even when
THREAD_INFO_IN_TASK is enabled, so add it back to s390's definition of
struct thread_info.

Note that s390 always has CONFIG_SMP=y so there is no point in guarding
the CPU field with an #ifdef.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>

s390/thread_info.h: fix task_struct declaration warning

Add missing forward declaration for task_struct.
The warning appears when the -Werror C compiler flag is being used.

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390: convert to generic entry

This patch converts s390 to use the generic entry infrastructure from
kernel/entry/*.

There are a few special things on s390:

- PIF_PER_TRAP is moved to TIF_PER_TRAP as the generic code doesn't
know about our PIF flags in exit_to_user_mode_loop().

- The old code had several ways to restart syscalls:

a) PIF_SYSCALL_RESTART, which was only set during execve to force a
restart after upgrading a process (usually qemu-kvm) to pgste page
table extensions.

b) PIF_SYSCALL, which is set by do_signal() to indicate that the
current syscall should be restarted. This is changed so that
do_signal() now also uses PIF_SYSCALL_RESTART. Continuing to use
PIF_SYSCALL doesn't work with the generic code, and changing it
to PIF_SYSCALL_RESTART makes PIF_SYSCALL and PIF_SYSCALL_RESTART
more unique.

- On s390 calling sys_sigreturn or sys_rt_sigreturn is implemented by
executing a svc instruction on the process stack which causes a fault.
While handling that fault the fault code sets PIF_SYSCALL to hand over
processing to the syscall code on exit to usermode.

The patch introduces PIF_SYSCALL_RET_SET, which is set if ptrace sets
a return value for a syscall. The s390x ptrace ABI uses r2 both for the
syscall number and return value, so ptrace cannot set the syscall number +
return value at the same time. The flag makes handling that a bit easier.
do_syscall() will just skip executing the syscall if PIF_SYSCALL_RET_SET
is set.

CONFIG_DEBUG_ASCE was removd in favour of the generic CONFIG_DEBUG_ENTRY.
CR1/7/13 will be checked both on kernel entry and exit to contain the
correct asces.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/decompressor: add stacktrace support

Decompressor works on a single statically allocated stack. Stacktrace
implementation with -mbackchain just takes few lines of code.

Linux version 5.10.0-rc3-22793-g0f84a355b776-dirty (gor@tuxmaker) #27 SMP PREEMPT Mon Nov 9 17:30:18 CET 2020
Kernel fault: interruption code 0005 ilc:2
PSW : 0000000180000000 0000000000012f92 (parse_boot_command_line+0x27a/0x46c)
R:0 T:0 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 RI:0 EA:3
GPRS: 0000000000000000 00ffffffffffffff 0000000000000000 000000000001a62c
000000000000bf60 0000000000000000 00000000000003c0 0000000000000000
0000000000000080 000000000002322d 000000007f29ef20 0000000000efd018
000000000311c000 0000000000010070 0000000000012f82 000000000000bea8
Call Trace:
(sp:000000000000bea8 [<000000000002016e>] 000000000002016e)
sp:000000000000bf18 [<0000000000012408>] startup_kernel+0x88/0x2fc
sp:000000000000bf60 [<00000000000100c4>] startup_normal+0xb0/0xb0

Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390: add support for TIF_NOTIFY_SIGNAL

Wire up TIF_NOTIFY_SIGNAL handling for s390.

Cc: linux-s390@vger.kernel.org
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390: Break cyclic percpu include

In order to use <asm/percpu.h> in irqflags.h, we need to make sure
asm/percpu.h does not itself depend on irqflags.h

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200623083721.396143816@infradead.org

arch: replace _BITUL() in kernel-space headers with BIT()

Now that BIT() can be used from assembly code, we can safely replace
_BITUL() with equivalent BIT().

UAPI headers are still required to use _BITUL(), but there is no more
reason to use it in kernel headers. BIT() is shorter.

Link: http://lkml.kernel.org/r/20190609153941.17249-2-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

s390/kasan: increase instrumented stack size to 64k

Increase kasan instrumented kernel stack size from 32k to 64k. Other
architectures seems to get away with just doubling kernel stack size under
kasan, but on s390 this appears to be not enough due to bigger frame size.
The particular pain point is kasan inlined checks (CONFIG_KASAN_INLINE
vs CONFIG_KASAN_OUTLINE). With inlined checks one particular case hitting
stack overflow is fs sync on xfs filesystem:

#0 [9a0681e8] 704 bytes check_usage at 34b1fc
#1 [9a0684a8] 432 bytes check_usage at 34c710
#2 [9a068658] 1048 bytes validate_chain at 35044a
#3 [9a068a70] 312 bytes __lock_acquire at 3559fe
#4 [9a068ba8] 440 bytes lock_acquire at 3576ee
#5 [9a068d60] 104 bytes _raw_spin_lock at 21b44e0
#6 [9a068dc8] 1992 bytes enqueue_entity at 2dbf72
#7 [9a069590] 1496 bytes enqueue_task_fair at 2df5f0
#8 [9a069b68] 64 bytes ttwu_do_activate at 28f438
#9 [9a069ba8] 552 bytes try_to_wake_up at 298c4c
#10 [9a069dd0] 168 bytes wake_up_worker at 23f97c
#11 [9a069e78] 200 bytes insert_work at 23fc2e
#12 [9a069f40] 648 bytes __queue_work at 2487c0
#13 [9a06a1c8] 200 bytes __queue_delayed_work at 24db28
#14 [9a06a290] 248 bytes mod_delayed_work_on at 24de84
#15 [9a06a388] 24 bytes kblockd_mod_delayed_work_on at 153e2a0
#16 [9a06a3a0] 288 bytes __blk_mq_delay_run_hw_queue at 158168c
#17 [9a06a4c0] 192 bytes blk_mq_run_hw_queue at 1581a3c
#18 [9a06a580] 184 bytes blk_mq_sched_insert_requests at 15a2192
#19 [9a06a638] 1024 bytes blk_mq_flush_plug_list at 1590f3a
#20 [9a06aa38] 704 bytes blk_flush_plug_list at 1555028
#21 [9a06acf8] 320 bytes schedule at 219e476
#22 [9a06ae38] 760 bytes schedule_timeout at 21b0aac
#23 [9a06b130] 408 bytes wait_for_common at 21a1706
#24 [9a06b2c8] 360 bytes xfs_buf_iowait at fa1540
#25 [9a06b430] 256 bytes __xfs_buf_submit at fadae6
#26 [9a06b530] 264 bytes xfs_buf_read_map at fae3f6
#27 [9a06b638] 656 bytes xfs_trans_read_buf_map at 10ac9a8
#28 [9a06b8c8] 304 bytes xfs_btree_kill_root at e72426
#29 [9a06b9f8] 288 bytes xfs_btree_lookup_get_block at e7bc5e
#30 [9a06bb18] 624 bytes xfs_btree_lookup at e7e1a6
#31 [9a06bd88] 2664 bytes xfs_alloc_ag_vextent_near at dfa070
#32 [9a06c7f0] 144 bytes xfs_alloc_ag_vextent at dff3ca
#33 [9a06c880] 1128 bytes xfs_alloc_vextent at e05fce
#34 [9a06cce8] 584 bytes xfs_bmap_btalloc at e58342
#35 [9a06cf30] 1336 bytes xfs_bmapi_write at e618de
#36 [9a06d468] 776 bytes xfs_iomap_write_allocate at ff678e
#37 [9a06d770] 720 bytes xfs_map_blocks at f82af8
#38 [9a06da40] 928 bytes xfs_writepage_map at f83cd6
#39 [9a06dde0] 320 bytes xfs_do_writepage at f85872
#40 [9a06df20] 1320 bytes write_cache_pages at 73dfe8
#41 [9a06e448] 208 bytes xfs_vm_writepages at f7f892
#42 [9a06e518] 88 bytes do_writepages at 73fe6a
#43 [9a06e570] 872 bytes __writeback_single_inode at a20cb6
#44 [9a06e8d8] 664 bytes writeback_sb_inodes at a23be2
#45 [9a06eb70] 296 bytes __writeback_inodes_wb at a242e0
#46 [9a06ec98] 928 bytes wb_writeback at a2500e
#47 [9a06f038] 848 bytes wb_do_writeback at a260ae
#48 [9a06f388] 536 bytes wb_workfn at a28228
#49 [9a06f5a0] 1088 bytes process_one_work at 24a234
#50 [9a06f9e0] 1120 bytes worker_thread at 24ba26
#51 [9a06fe40] 104 bytes kthread at 26545a
#52 [9a06fea8] kernel_thread_starter at 21b6b62

To be able to increase the stack size to 64k reuse LLILL instruction
in __switch_to function to load 64k - STACK_FRAME_OVERHEAD - __PT_SIZE
(65192) value as unsigned.

Reported-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/head: avoid doubling early boot stack size under KASAN

Early boot stack uses predefined 4 pages of memory 0x8000-0xC000. This
stack is used to run not instumented decompressor/facilities
verification C code. It doesn't make sense to double its size when
the kernel is built with KASAN support. BOOT_STACK_ORDER is introduced
to avoid that.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/kasan: double the stack size

Kasan stack instrumentation pads stack variables with redzones, which
increases stack frames size significantly. Stack sizes are increased
from 16k to 32k in the code, as well as for the kernel stack overflow
detection option (CHECK_STACK).

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: unify stack size definitions

Remove STACK_ORDER and STACK_SIZE in favour of identical THREAD_SIZE_ORDER
and THREAD_SIZE definitions. THREAD_SIZE and THREAD_SIZE_ORDER naming is
misleading since it is used as general kernel stack size information. But
both those definitions are used in the common code and throughout
architectures specific code, so changing the naming is problematic.

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: add support for virtually mapped kernel stacks

With virtually mapped kernel stacks the kernel stack overflow detection
is now fault based, every stack has a guard page in the vmalloc space.
The panic_stack is renamed to nodat_stack and is used for all function
that need to run without DAT, e.g. memcpy_real or do_start_kdump.

The main effect is a reduction in the kernel image size as with vmap
stacks the old style overflow checking that adds two instructions per
function is not needed anymore. Result from bloat-o-meter:

add/remove: 20/1 grow/shrink: 13/26854 up/down: 2198/-216240 (-214042)

In regard to performance the micro-benchmark for fork has a hit of a
few microseconds, allocating 4 pages in vmalloc space is more expensive
compare to an order-2 page allocation. But with real workload I could
not find a noticeable difference.

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: update sampling tag after task pid change

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 <schwidefsky@de.ibm.com>

s390: run user space and KVM guests with modified branch prediction

Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary
plumbing in entry.S to be able to run user space and KVM guests with
limited branch prediction.

To switch a user space process to limited branch prediction the
s390_isolate_bp() function has to be call, and to run a vCPU of a KVM
guest associated with the current task with limited branch prediction
call s390_isolate_bp_guest().

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Construct init thread stack in the linker script rather than by union

Construct the init thread stack in the linker script rather than doing it
by means of a union so that ia64's init_task.c can be got rid of.

The following symbols are then made available from INIT_TASK_DATA() linker
script macro:

init_thread_union
init_stack

INIT_TASK_DATA() also expands the region to THREAD_SIZE to accommodate the
size of the init stack. init_thread_union is given its own section so that
it can be placed into the stack space in the right order. I'm assuming
that the ia64 ordering is correct and that the task_struct is first and the
thread_info second.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Will Deacon <will.deacon@arm.com> (arm64)
Tested-by: Palmer Dabbelt <palmer@sifive.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

s390/kvm: avoid global config of vm.alloc_pgste=1

The system control vm.alloc_pgste is used to control the size of the
page tables, either 2K or 4K. The idea is that a KVM host sets the
vm.alloc_pgste control to 1 which causes *all* new processes to run
with 4K page tables. For a non-kvm system the control should stay off
to save on memory used for page tables.

Trouble is that distributions choose to set the control globally to
be able to run KVM guests. This wastes memory on non-KVM systems.

Introduce the PT_S390_PGSTE ELF segment type to "mark" the qemu
executable with it. All executables with this (empty) segment in
its ELF phdr array will be started with 4K page tables. Any executable
without PT_S390_PGSTE will run with the default 2K page tables.

This removes the need to set vm.alloc_pgste=1 for a KVM host and
minimizes the waste of memory for page tables.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: add a system call for guarded storage

This adds a new system call to enable the use of guarded storage for
user space processes. The system call takes two arguments, a command
and pointer to a guarded storage control block:

s390_guarded_storage(int command, struct gs_cb *gs_cb);

The second argument is relevant only for the GS_SET_BC_CB command.

The commands in detail:

0 - GS_ENABLE
Enable the guarded storage facility for the current task. The
initial content of the guarded storage control block will be
all zeros. After the enablement the user space code can use
load-guarded-storage-controls instruction (LGSC) to load an
arbitrary control block. While a task is enabled the kernel
will save and restore the current content of the guarded
storage registers on context switch.
1 - GS_DISABLE
Disables the use of the guarded storage facility for the current
task. The kernel will cease to save and restore the content of
the guarded storage registers, the task specific content of
these registers is lost.
2 - GS_SET_BC_CB
Set a broadcast guarded storage control block. This is called
per thread and stores a specific guarded storage control block
in the task struct of the current task. This control block will
be used for the broadcast event GS_BROADCAST.
3 - GS_CLEAR_BC_CB
Clears the broadcast guarded storage control block. The guarded-
storage control block is removed from the task struct that was
established by GS_SET_BC_CB.
4 - GS_BROADCAST
Sends a broadcast to all thread siblings of the current task.
Every sibling that has established a broadcast guarded storage
control block will load this control block and will be enabled
for guarded storage. The broadcast guarded storage control block
is used up, a second broadcast without a refresh of the stored
control block with GS_SET_BC_CB will not have any effect.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

livepatch/s390: add TIF_PATCH_PENDING thread flag

Update a task's patch state when returning from a system call or user
space interrupt, or after handling a signal.

This greatly increases the chances of a patch operation succeeding. If
a task is I/O bound, it can be patched when returning from a system
call. If a task is CPU bound, it can be patched when returning from an
interrupt. If a task is sleeping on a to-be-patched function, the user
can send SIGSTOP and SIGCONT to force it to switch.

Since there are two ways the syscall can be restarted on return from a
signal handling process, it is important to clear the flag before
do_signal() is called. Otherwise we could miss the migration if we used
SIGSTOP/SIGCONT procedure or fake signal to migrate patching blocking
tasks. If we place our hook to sysc_work label in entry before
TIF_SIGPENDING is evaluated we kill two birds with one stone. The task
is correctly migrated in all return paths from a syscall.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

livepatch/s390: reorganize TIF thread flag bits

Group the TIF thread flag bits by their inclusion in the _TIF_WORK and
_TIF_TRACE macros.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

s390/thread_info: get rid of THREAD_ORDER define

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 <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: move sys_call_table and last_break from thread_info to thread_struct

Move the last two architecture specific fields from the thread_info
structure to the thread_struct. All that is left in thread_info is
the flags field.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: move cputime accounting fields from thread_info to thread_struct

The user_timer and system_timer fields are used for the per-thread
cputime accounting code. The access to these values is simpler if
they are moved to the thread_struct as the task_thread_info(tsk)
indirection is not needed anymore.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: move system_call field from thread_info to thread_struct

The system_call field in thread_info structure is used by the signal
code to store the number of the current system call while the debugger
interacts with its inferior. A better location for the system_call
field is with the other debugger related information in the
thread_struct.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: move thread_info into task_struct

This is the s390 variant of commit 15f4eae70d36 ("x86: Move
thread_info into task_struct").

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/preempt: move preempt_count to the lowcore

Convert s390 to use a field in the struct lowcore for the CPU
preemption count. It is a bit cheaper to access a lowcore field
compared to a thread_info variable and it removes the depencency
on a task related structure.

bloat-o-meter on the vmlinux image for the default configuration
(CONFIG_PREEMPT_NONE=y) reports a small reduction in text size:

add/remove: 0/0 grow/shrink: 18/578 up/down: 228/-5448 (-5220)

A larger improvement is achieved with the default configuration
but with CONFIG_PREEMPT=y and CONFIG_DEBUG_PREEMPT=n:

add/remove: 2/6 grow/shrink: 59/4477 up/down: 1618/-228762 (-227144)

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: add missing declarations

arch_dup_task_struct and the per cpu variable mt_cycles are globally
visible, but do not have any header file with a declaration.
Therefore add it so we have proper type checking in place.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: remove is_32bit_task() helper

is_32bit_task() used to be helpful when we still had CONFIG_32BIT.
Since that is gone, it is nowadays identical to is_compat_task().
So remove it.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/flags: use _BITUL macro

The defines that are used in entry.S have been partially converted to
use the _BITUL macro (setup.h). This patch converts the rest.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: Remove signal translation and exec_domain

As execution domain support is gone we can remove
signal translation from the signal code and remove
exec_domain from thread_info.

Signed-off-by: Richard Weinberger <richard@nod.at>

s390: add missing arch_release_task_struct() declaration

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: remove 31 bit support

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

all arches, signal: move restart_block to struct task_struct

If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target. This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: Richard Weinberger <richard@nod.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

s390/uprobes: architecture backend for uprobes

Signed-off-by: Jan Willeke <willeke@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: split TIF bits into CIF, PIF and TIF bits

The oi and ni instructions used in entry[64].S to set and clear bits
in the thread-flags are not guaranteed to be atomic in regard to other
CPUs. Split the TIF bits into CPU, pt_regs and thread-info specific
bits. Updates on the TIF bits are done with atomic instructions,
updates on CPU and pt_regs bits are done with non-atomic instructions.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/uaccess: simplify control register updates

Always switch to the kernel ASCE in switch_mm. Load the secondary
space ASCE in finish_arch_post_lock_switch after checking that
any pending page table operations have completed. The primary
ASCE is loaded in entry[64].S. With this the update_primary_asce
call can be removed from the switch_to macro and from the start
of switch_mm function. Remove the load_primary argument from
update_user_asce/clear_user_asce, rename update_user_asce to
set_user_asce and rename update_primary_asce to load_kernel_asce.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/uaccess: rework uaccess code - fix locking issues

The current uaccess code uses a page table walk in some circumstances,
e.g. in case of the in atomic futex operations or if running on old
hardware which doesn't support the mvcos instruction.

However it turned out that the page table walk code does not correctly
lock page tables when accessing page table entries.
In other words: a different cpu may invalidate a page table entry while
the current cpu inspects the pte. This may lead to random data corruption.

Adding correct locking however isn't trivial for all uaccess operations.
Especially copy_in_user() is problematic since that requires to hold at
least two locks, but must be protected against ABBA deadlock when a
different cpu also performs a copy_in_user() operation.

So the solution is a different approach where we change address spaces:

User space runs in primary address mode, or access register mode within
vdso code, like it currently already does.

The kernel usually also runs in home space mode, however when accessing
user space the kernel switches to primary or secondary address mode if
the mvcos instruction is not available or if a compare-and-swap (futex)
instruction on a user space address is performed.
KVM however is special, since that requires the kernel to run in home
address space while implicitly accessing user space with the sie
instruction.

So we end up with:

User space:
- runs in primary or access register mode
- cr1 contains the user asce
- cr7 contains the user asce
- cr13 contains the kernel asce

Kernel space:
- runs in home space mode
- cr1 contains the user or kernel asce
-> the kernel asce is loaded when a uaccess requires primary or
secondary address mode
- cr7 contains the user or kernel asce, (changed with set_fs())
- cr13 contains the kernel asce

In case of uaccess the kernel changes to:
- primary space mode in case of a uaccess (copy_to_user) and uses
e.g. the mvcp instruction to access user space. However the kernel
will stay in home space mode if the mvcos instruction is available
- secondary space mode in case of futex atomic operations, so that the
instructions come from primary address space and data from secondary
space

In case of kvm the kernel runs in home space mode, but cr1 gets switched
to contain the gmap asce before the sie instruction gets executed. When
the sie instruction is finished cr1 will be switched back to contain the
user asce.

A context switch between two processes will always load the kernel asce
for the next process in cr1. So the first exit to user space is a bit
more expensive (one extra load control register instruction) than before,
however keeps the code rather simple.

In sum this means there is no need to perform any error prone page table
walks anymore when accessing user space.

The patch seems to be rather large, however it mainly removes the
the page table walk code and restores the previously deleted "standard"
uaccess code, with a couple of changes.

The uaccess without mvcos mode can be enforced with the "uaccess_primary"
kernel parameter.

Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/ptrace: add support for PTRACE_SINGLEBLOCK

The PTRACE_SINGLEBLOCK option is used to get control whenever
the inferior has executed a successful branch. The PER option to
implement block stepping is successful-branching event, bit 32
in the PER-event mask.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/mm,tlb: race of lazy TLB flush vs. recreation of TLB entries

Git commit 050eef364ad70059 "[S390] fix tlb flushing vs. concurrent
/proc accesses" introduced the attach counter to avoid using the
mm_users value to decide between IPTE for every PTE and lazy TLB
flushing with IDTE. That fixed the problem with mm_users but it
introduced another subtle race, fortunately one that is very hard
to hit.
The background is the requirement of the architecture that a valid
PTE may not be changed while it can be used concurrently by another
cpu. The decision between IPTE and lazy TLB flushing needs to be
done while the PTE is still valid. Now if the virtual cpu is
temporarily stopped after the decision to use lazy TLB flushing but
before the invalid bit of the PTE has been set, another cpu can attach
the mm, find that flush_mm is set, do the IDTE, return to userspace,
and recreate a TLB that uses the PTE in question. When the first,
stopped cpu continues it will change the PTE while it is attached on
another cpu. The first cpu will do another IDTE shortly after the
modification of the PTE which makes the race window quite short.

To fix this race the CPU that wants to attach the address space of a
user space thread needs to wait for the end of the PTE modification.
The number of concurrent TLB flushers for an mm is tracked in the
upper 16 bits of the attach_count and finish_arch_post_lock_switch
is used to wait for the end of the flush operation if required.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

preempt: Make PREEMPT_ACTIVE generic

No point in having this bit defined by architecture.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130917183629.090698799@linutronix.de

s390: remove small stack config option

We've seen repeatedly that 8KB stack size on 64 bit kernels
is not sufficient.
So simply remove the config option.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: system call path micro optimization

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 <schwidefsky@de.ibm.com>

sanitize tsk_is_polling()

Make default just return 0. The current default (checking
TIF_POLLING_NRFLAG) is taken to architectures that need it;
ones that don't do polling in their idle threads don't need
to defined TIF_POLLING_NRFLAG at all.

ia64 defined both TS_POLLING (used by its tsk_is_polling())
and TIF_POLLING_NRFLAG (not used at all). Killed the latter...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

bury _TIF_RESTORE_SIGMASK

never used...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

s390/comments: unify copyright messages and remove file names

Remove the file name from the comment at top of many files. In most
cases the file name was wrong anyway, so it's rather pointless.

Also unify the IBM copyright statement. We did have a lot of sightly
different statements and wanted to change them one after another
whenever a file gets touched. However that never happened. Instead
people start to take the old/"wrong" statements to use as a template
for new files.
So unify all of them in one go.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

s390/headers: replace __s390x__ with CONFIG_64BIT where possible

Replace __s390x__ with CONFIG_64BIT in all places that are not exported
to userspace or guarded with #ifdef __KERNEL__.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/headers: remove #ifdef __KERNEL__ from not exported headers

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: replace TIF_SIE with PF_VCPU

Replace the check for TIF_SIE in the fault handler by a check for PF_VCPU.
With the last user of TIF_SIE gone we can now remove the bit.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

freezer: remove now unused TIF_FREEZE

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org

[S390] add TIF_SYSCALL thread flag

Add an explicit TIF_SYSCALL bit that indicates if a task is inside
a system call. The svc_code in the pt_regs structure is now only
valid if TIF_SYSCALL is set. With this definition TIF_RESTART_SVC
can be replaced with TIF_SYSCALL. Overall do_signal is a bit more
readable and it saves a few lines of code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] signal race with restarting system calls

For a ERESTARTNOHAND/ERESTARTSYS/ERESTARTNOINTR restarting system call
do_signal will prepare the restart of the system call with a rewind of
the PSW before calling get_signal_to_deliver (where the debugger might
take control). For A ERESTART_RESTARTBLOCK restarting system call
do_signal will set -EINTR as return code.
There are two issues with this approach:
1) strace never sees ERESTARTNOHAND, ERESTARTSYS, ERESTARTNOINTR or
ERESTART_RESTARTBLOCK as the rewinding already took place or the
return code has been changed to -EINTR
2) if get_signal_to_deliver does not return with a signal to deliver
the restart via the repeat of the svc instruction is left in place.
This opens a race if another signal is made pending before the
system call instruction can be reexecuted. The original system call
will be restarted even if the second signal would have ended the
system call with -EINTR.

These two issues can be solved by dropping the early rewind of the
system call before get_signal_to_deliver has been called and by using
the TIF_RESTART_SVC magic to do the restart if no signal has to be
delivered. The only situation where the system call restart via the
repeat of the svc instruction is appropriate is when a SA_RESTART
signal is delivered to user space.

Unfortunately this breaks inferior calls by the debugger again. The
system call number and the length of the system call instruction is
lost over the inferior call and user space will see ERESTARTNOHAND/
ERESTARTSYS/ERESTARTNOINTR/ERESTART_RESTARTBLOCK. To correct this a
new ptrace interface is added to save/restore the system call number
and system call instruction length.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] fix _TIF_SINGLE_STEP definition

_TIF_SINGLE_STEP is incorrectly defined as 1<<TIF_FREEZE. Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] move sie code to entry.S

The entry to / exit from sie has subtle dependencies to the first level
interrupt handler. Move the sie assembler code to entry64.S and replace
the SIE_HOOK callback with a test and the new _TIF_SIE bit.
In addition this patch fixes several problems in regard to the check for
the_TIF_EXIT_SIE bits. The old code checked the TIF bits before executing
the interrupt handler and it only modified the instruction address if it
pointed directly to the sie instruction. In both cases it could miss
a TIF bit that normally would cause an exit from the guest and would
reenter the guest context.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] Add is_32bit_task() helper function

Helper function which tells us if a task is running in ESA mode.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] ptrace cleanup

Overhaul program event recording and the code dealing with the ptrace
user space interface.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] current_thread_info optimization

Use thread_info lowcore field for current_thread_info(), saves
an unnecessary calculation.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] add breaking event address for user space

Copy the last breaking event address from the lowcore to a new
field in the thread_struct on each system entry. Add a new
ptrace request PTRACE_GET_LAST_BREAK and a new utrace regset
REGSET_LAST_BREAK to query the last breaking event.

This is useful for debugging wild branches in user space code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

add descriptive comment for TIF_MEMDIE task flag declaration.

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

[S390] Cleanup struct _lowcore usage and defines.

Use asm offsets to make sure the offset defines to struct _lowcore and
its layout don't get out of sync.
Also add a BUILD_BUG_ON() which checks that the size of the structure
is sane.
And while being at it change those sites which use odd casts to access
the current lowcore. These should use S390_lowcore instead.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] remove superfluous TIF_USEDFPU bit

The TIF_USEDFPU bit is always 0 for s390 and it is not tested anywhere.
Remove the bit. At the same time remove the calls to clear_used_math()
as well. The PF_USED_MATH bit is never set for s390 either.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

tracing: Rename FTRACE_SYSCALLS for tracepoints

s/HAVE_FTRACE_SYSCALLS/HAVE_SYSCALL_TRACEPOINTS/g
s/TIF_SYSCALL_FTRACE/TIF_SYSCALL_TRACEPOINT/g

The syscall enter/exit tracing is no longer specific to just ftrace, so
they now have names that reflect their tie to tracepoints instead.

Signed-off-by: Josh Stone <jistone@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <1251150194-1713-2-git-send-email-jistone@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

sched: INIT_PREEMPT_COUNT

Pull the initial preempt_count value into a single
definition site.

Maintainers for: alpha, ia64 and m68k, please have a look,
your arch code is funny.

The header magic is a bit odd, but similar to the KERNEL_DS
one, CPP waits with expanding these macros until the
INIT_THREAD_INFO macro itself is expanded, which is in
arch/*/kernel/init_task.c where we've already included
sched.h so we're good.

Cc: tony.luck@intel.com
Cc: rth@twiddle.net
Cc: geert@linux-m68k.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[S390] ftrace: add system call tracer support

System call tracer support for s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] secure computing arch backend

Enable secure computing on s390 as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] s390: move machine flags to lowcore

Currently the storage of the machine flags is a globally exported unsigned
long long variable. By moving the storage location into the lowcore struct we
allow assembler code to check machine_flags directly even without needing a
register. Addtionally the lowcore and therefore the machine flags too will be
in cache most of the time.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[PATCH] improve precision of process accounting.

The unit of the cputime accouting values that are stored per process is
currently a microsecond. The CPU timer has a maximum granularity of
2**-12 microseconds. There is no benefit in storing the per process values
in the lesser precision and there is the disadvantage that the backend
has to do the rounding to microseconds. The better solution is to use
the maximum granularity of the CPU timer as cputime unit.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] No more 4kb stacks.

We got a stack overflow with a small stack configuration on a 32 bit
system. It just looks like as 4kb isn't enough and too dangerous.
So lets get rid of 4kb stacks on 32 bit.

But one thing I completely dislike about the call trace below is that
just for debugging or tracing purposes sprintf gets called (cio_start_key):

/* process condition code */
sprintf(dbf_txt, "ccode:%d", ccode);
CIO_TRACE_EVENT(4, dbf_txt);

But maybe its just me who thinks that this could be done better.

<4>Kernel stack overflow.
<4>Modules linked in: dm_multipath sunrpc bonding qeth_l2 dm_mod qeth ccwgroup vmur
<4>CPU: 1 Not tainted 2.6.27-30.x.20081015-s390default #1
<4>Process httpd (pid: 3807, task: 20ae2df8, ksp: 1666fb78)
<4>Krnl PSW : 040c0000 8027098a (number+0xe/0x348)
<4> R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0
<4>Krnl GPRS: 00d43318 0027097c 1666f277 9666f270
<4> 00000000 00000000 0000000a ffffffff
<4> 9666f270 1666f228 1666f277 1666f098
<4> 00000002 80270982 80271016 1666f098
<4>Krnl Code: 8027097e: f0340dd0a7f1 srp 3536(4,%r0),2033(%r10),4
<4> 80270984: 0f00 clcl %r0,%r0
<4> 80270986: a7840001 brc 8,80270988
<4> >8027098a: 18ef lr %r14,%r15
<4> 8027098c: a7faff68 ahi %r15,-152
<4> 80270990: 18bf lr %r11,%r15
<4> 80270992: 18a2 lr %r10,%r2
<4> 80270994: 1893 lr %r9,%r3

Modified calltrace with annotated stackframe size of each function:

stackframe size
|
0 304 vsnprintf+850 [0x271016]
1 72 sprintf+74 [0x271522]
2 56 cio_start_key+262 [0x2d4c16]
3 56 ccw_device_start_key+222 [0x2dfe92]
4 56 ccw_device_start+40 [0x2dff28]
5 48 raw3215_start_io+104 [0x30b0f8]
6 56 raw3215_write+494 [0x30ba0a]
7 40 con3215_write+68 [0x30bafc]
8 40 __call_console_drivers+146 [0x12b0fa]
9 32 _call_console_drivers+102 [0x12b192]
10 64 release_console_sem+268 [0x12b614]
11 168 vprintk+462 [0x12bca6]
12 72 printk+68 [0x12bfd0]
13 256 __print_symbol+50 [0x15a882]
14 56 __show_trace+162 [0x103d06]
15 32 show_trace+224 [0x103e70]
16 48 show_stack+152 [0x103f20]
17 56 dump_stack+126 [0x104612]
18 96 __alloc_pages_internal+592 [0x175004]
19 80 cache_alloc_refill+776 [0x196f3c]
20 40 __kmalloc+258 [0x1972ae]
21 40 __alloc_skb+94 [0x328086]
22 32 pskb_copy+50 [0x328252]
23 32 skb_realloc_headroom+110 [0x328a72]
24 104 qeth_l2_hard_start_xmit+378 [0x7803bfde]
25 56 dev_hard_start_xmit+450 [0x32ef6e]
26 56 __qdisc_run+390 [0x3425d6]
27 48 dev_queue_xmit+410 [0x331e06]
28 40 ip_finish_output+308 [0x354ac8]
29 56 ip_output+218 [0x355b6e]
30 24 ip_local_out+56 [0x354584]
31 120 ip_queue_xmit+300 [0x355cec]
32 96 tcp_transmit_skb+812 [0x367da8]
33 40 tcp_push_one+158 [0x369fda]
34 112 tcp_sendmsg+852 [0x35d5a0]
35 240 sock_sendmsg+164 [0x32035c]
36 56 kernel_sendmsg+86 [0x32064a]
37 88 sock_no_sendpage+98 [0x322b22]
38 104 tcp_sendpage+70 [0x35cc1e]
39 48 sock_sendpage+74 [0x31eb66]
40 64 pipe_to_sendpage+102 [0x1c4b2e]
41 64 __splice_from_pipe+120 [0x1c5340]
42 72 splice_from_pipe+90 [0x1c57e6]
43 56 generic_splice_sendpage+38 [0x1c5832]
44 48 do_splice_from+104 [0x1c4c38]
45 48 direct_splice_actor+52 [0x1c4c88]
46 80 splice_direct_to_actor+180 [0x1c4f80]
47 72 do_splice_direct+70 [0x1c5112]
48 64 do_sendfile+360 [0x19de18]
49 72 sys_sendfile64+126 [0x19df32]
50 336 sysc_do_restart+18 [0x111a1a]

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

container freezer: add TIF_FREEZE flag to all architectures

This patch series introduces a cgroup subsystem that utilizes the swsusp
freezer to freeze a group of tasks. It's immediately useful for batch job
management scripts. It should also be useful in the future for
implementing container checkpoint/restart.

The freezer subsystem in the container filesystem defines a cgroup file
named freezer.state. Reading freezer.state will return the current state
of the cgroup. Writing "FROZEN" to the state file will freeze all tasks
in the cgroup. Subsequently writing "RUNNING" will unfreeze the tasks in
the cgroup.

* Examples of usage :

# mkdir /containers/freezer
# mount -t cgroup -ofreezer freezer /containers
# mkdir /containers/0
# echo $some_pid > /containers/0/tasks

to get status of the freezer subsystem :

# cat /containers/0/freezer.state
RUNNING

to freeze all tasks in the container :

# echo FROZEN > /containers/0/freezer.state
# cat /containers/0/freezer.state
FREEZING
# cat /containers/0/freezer.state
FROZEN

to unfreeze all tasks in the container :

# echo RUNNING > /containers/0/freezer.state
# cat /containers/0/freezer.state
RUNNING

This patch:

The first step in making the refrigerator() available to all
architectures, even for those without power management.

The purpose of such a change is to be able to use the refrigerator() in a
new control group subsystem which will implement a control group freezer.

[akpm@linux-foundation.org: fix sparc]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Pavel Machek <pavel@suse.cz>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@tuxonice.net>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[S390] ptrace changes

* System call parameter and result access functions
* Add tracehook calls
* Split syscall_trace into two functions do_syscall_trace_enter and
do_syscall_trace_exit

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] move include/asm-s390 to arch/s390/include/asm

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>