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Author SHA1 Message Date
Sven Schnelle
fa2ae4a377 s390/idle: Rewrite psw_idle() in C
To ease maintenance and further enhancements, convert
the psw_idle() function to C.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-05-14 13:37:07 +02:00
Josh Poimboeuf
071c44e427 sched/idle: Mark arch_cpu_idle_dead() __noreturn
Before commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead()
return"), in Xen, when a previously offlined CPU was brought back
online, it unexpectedly resumed execution where it left off in the
middle of the idle loop.

There were some hacks to make that work, but the behavior was surprising
as do_idle() doesn't expect an offlined CPU to return from the dead (in
arch_cpu_idle_dead()).

Now that Xen has been fixed, and the arch-specific implementations of
arch_cpu_idle_dead() also don't return, give it a __noreturn attribute.

This will cause the compiler to complain if an arch-specific
implementation might return.  It also improves code generation for both
caller and callee.

Also fixes the following warning:

  vmlinux.o: warning: objtool: do_idle+0x25f: unreachable instruction

Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-03-08 08:44:28 -08:00
Linus Torvalds
bcf5470eb4 s390 updates for 6.3 merge window
- Large cleanup of the con3270/tty3270 driver. Among others this fixes:
   * Background Color Support
   * ASCII Line Character Support
   * VT100 Support
   * Geometries other than 80x24
 
 - Cleanup and improve cmpxchg() code. Also add cmpxchg_user_key() to
   uaccess functions, which will be used by KVM to access KVM guest memory
   with a specific storage key.
 
 - Add support for user space events counting to CPUMF.
 
 - Cleanup the vfio/ccw code, which also allows now to properly support 2K
   Format-2 IDALs.
 
 - Move kernel page table allocation and initialization to decompressor,
   which finally allows to enter the kernel with dynamic address translation
   enabled. This in turn allows to get rid of code with special handling in
   the kernel, which has to distinguish if DAT is on or off.
 
 - Replace kretprobe with rethook.
 
 - Various improvements to vfio/ap queue resets:
   * Use TAPQ to verify completion of a reset in progress rather than
     multiple invocations of ZAPQ.
   * Check TAPQ response codes when verifying successful completion of ZAPQ.
   * Fix erroneous handling of some error response codes.
   * Increase the maximum amount of time to wait for successful completion
     of ZAPQ.
 
 - Rework system call wrappers to get rid of alias functions, which were
   only left on s390.
 
 - Cleanup diag288_wdt watchdog driver. It has been agreed on with Guenter
   Roeck that this goes upstream via the s390 tree.
 
 - Add missing loadparm parameter handling for list-directed ECKD ipl/reipl.
 
 - Various improvements to memory detection code.
 
 - Remove arch_cpu_idle_time() since the current implementation is broken,
   and allows user space observable accounted idle times which can
   temporarily decrease.
 
 - Add Reset DAT-Protection support: (only) allow to change PTEs from RO to
   RW with a new RDP instruction. Unlike the currently used IPTE
   instruction, this does not necessarily guarantee that TLBs of all CPUs
   are synchronously flushed; and that remote CPUs can see spurious
   protection faults. The overall improvement for not requiring an all CPU
   synchronization, like it is required with IPTE, should be beneficial.
 
 - Fix KFENCE page fault reporting.
 
 - Smaller cleanups and improvement all over the place.
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Merge tag 's390-6.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

 - Large cleanup of the con3270/tty3270 driver. Among others this fixes:
     - Background Color Support
     - ASCII Line Character Support
     - VT100 Support
     - Geometries other than 80x24

 - Cleanup and improve cmpxchg() code. Also add cmpxchg_user_key() to
   uaccess functions, which will be used by KVM to access KVM guest
   memory with a specific storage key

 - Add support for user space events counting to CPUMF

 - Cleanup the vfio/ccw code, which also allows now to properly support
   2K Format-2 IDALs

 - Move kernel page table allocation and initialization to decompressor,
   which finally allows to enter the kernel with dynamic address
   translation enabled. This in turn allows to get rid of code with
   special handling in the kernel, which has to distinguish if DAT is on
   or off

 - Replace kretprobe with rethook

 - Various improvements to vfio/ap queue resets:
     - Use TAPQ to verify completion of a reset in progress rather than
       multiple invocations of ZAPQ.
     - Check TAPQ response codes when verifying successful completion of
       ZAPQ.
     - Fix erroneous handling of some error response codes.
     - Increase the maximum amount of time to wait for successful
       completion of ZAPQ

 - Rework system call wrappers to get rid of alias functions, which were
   only left on s390

 - Cleanup diag288_wdt watchdog driver. It has been agreed on with
   Guenter Roeck that this goes upstream via the s390 tree

 - Add missing loadparm parameter handling for list-directed ECKD
   ipl/reipl

 - Various improvements to memory detection code

 - Remove arch_cpu_idle_time() since the current implementation is
   broken, and allows user space observable accounted idle times which
   can temporarily decrease

 - Add Reset DAT-Protection support: (only) allow to change PTEs from RO
   to RW with a new RDP instruction. Unlike the currently used IPTE
   instruction, this does not necessarily guarantee that TLBs of all
   CPUs are synchronously flushed; and that remote CPUs can see spurious
   protection faults. The overall improvement for not requiring an all
   CPU synchronization, like it is required with IPTE, should be
   beneficial

 - Fix KFENCE page fault reporting

 - Smaller cleanups and improvement all over the place

* tag 's390-6.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (182 commits)
  s390/irq,idle: simplify idle check
  s390/processor: add test_and_set_cpu_flag() and test_and_clear_cpu_flag()
  s390/processor: let cpu helper functions return boolean values
  s390/kfence: fix page fault reporting
  s390/zcrypt: introduce ctfm field in struct CPRBX
  s390: remove confusing comment from uapi types header file
  vfio/ccw: remove WARN_ON during shutdown
  s390/entry: remove toolchain dependent micro-optimization
  s390/mem_detect: do not truncate online memory ranges info
  s390/vx: remove __uint128_t type from __vector128 struct again
  s390/mm: add support for RDP (Reset DAT-Protection)
  s390/mm: define private VM_FAULT_* reasons from top bits
  Documentation: s390: correct spelling
  s390/ap: fix status returned by ap_qact()
  s390/ap: fix status returned by ap_aqic()
  s390: vfio-ap: tighten the NIB validity check
  Revert "s390/mem_detect: do not update output parameters on failure"
  s390/idle: remove arch_cpu_idle_time() and corresponding code
  s390/vx: use simple assignments to access __vector128 members
  s390/vx: add 64 and 128 bit members to __vector128 struct
  ...
2023-02-21 15:09:17 -08:00
Heiko Carstens
6472a2dcc4 s390/irq,idle: simplify idle check
Use the per-cpu CIF_ENABLED_WAIT flag to decide if an interrupt
occurred while a cpu was idle, instead of checking two conditions
within the old psw.

Also move clearing of the CIF_ENABLED_WAIT bit to the early interrupt
handler, which in turn makes arch_vcpu_is_preempted() also a bit more
precise, since the flag is now cleared before interrupt handlers have
been called.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-02-15 11:07:01 +01:00
Heiko Carstens
be76ea6144 s390/idle: remove arch_cpu_idle_time() and corresponding code
arch_cpu_idle_time() returns the idle time of any given cpu if it is in
idle, or zero if not. All if this is racy and partially incorrect. Time
stamps taken with store clock extended and store clock fast from different
cpus are compared, while the architecture states that this is nothing which
can be relied on (see Principles of Operation; Chapter 4, "Setting and
Inspecting the Clock").

A more fundamental problem is that the timestamp when a cpu is leaving idle
is taken early in the assembler part of the interrupt handler, and this
value is only transferred many cycles later to the cpu's per-cpu idle data
structure.

This per cpu data structure is read by arch_cpu_idle() to tell for which
period of time a remote cpu is idle: if only an idle_enter value is
present, the assumed idle time of the cpu is calculated by taking a local
timestamp and returning the difference of the local timestamp and the
idle_enter value. This is potentially incorrect, since the remote cpu may
have already left idle, but the taken timestamp may not have been
transferred to the per-cpu data structure. This in turn means that too much
idle time may be reported for a cpu, and a subsequent calculation of system
idle time may result in a smaller value.

Instead of coming up with even more complex code trying to fix this, just
remove this code, and only account idle time of a cpu, after idle state is
left.

Another minor bug is that it is assumed that timestamps are non-zero, which
is not necessarily the case for timestamps taken with store clock
fast. This however is just a very minor problem, since this can only happen
when the epoch increases.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-02-09 20:11:23 +01:00
Heiko Carstens
a9cbc1b471 s390/idle: mark arch_cpu_idle() noinstr
linux-next commit ("cpuidle: tracing: Warn about !rcu_is_watching()")
adds a new warning which hits on s390's arch_cpu_idle() function:

RCU not on for: arch_cpu_idle+0x0/0x28
WARNING: CPU: 2 PID: 0 at include/linux/trace_recursion.h:162 arch_ftrace_ops_list_func+0x24c/0x258
Modules linked in:
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.2.0-rc6-next-20230202 #4
Hardware name: IBM 8561 T01 703 (z/VM 7.3.0)
Krnl PSW : 0404d00180000000 00000000002b55c0 (arch_ftrace_ops_list_func+0x250/0x258)
           R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3
Krnl GPRS: c0000000ffffbfff 0000000080000002 0000000000000026 0000000000000000
           0000037ffffe3a28 0000037ffffe3a20 0000000000000000 0000000000000000
           0000000000000000 0000000000f4acf6 00000000001044f0 0000037ffffe3cb0
           0000000000000000 0000000000000000 00000000002b55bc 0000037ffffe3bb8
Krnl Code: 00000000002b55b0: c02000840051        larl    %r2,0000000001335652
           00000000002b55b6: c0e5fff512d1        brasl   %r14,0000000000157b58
          #00000000002b55bc: af000000            mc      0,0
          >00000000002b55c0: a7f4ffe7            brc     15,00000000002b558e
           00000000002b55c4: 0707                bcr     0,%r7
           00000000002b55c6: 0707                bcr     0,%r7
           00000000002b55c8: eb6ff0480024        stmg    %r6,%r15,72(%r15)
           00000000002b55ce: b90400ef            lgr     %r14,%r15
Call Trace:
 [<00000000002b55c0>] arch_ftrace_ops_list_func+0x250/0x258
([<00000000002b55bc>] arch_ftrace_ops_list_func+0x24c/0x258)
 [<0000000000f5f0fc>] ftrace_common+0x1c/0x20
 [<00000000001044f6>] arch_cpu_idle+0x6/0x28
 [<0000000000f4acf6>] default_idle_call+0x76/0x128
 [<00000000001cc374>] do_idle+0xf4/0x1b0
 [<00000000001cc6ce>] cpu_startup_entry+0x36/0x40
 [<0000000000119d00>] smp_start_secondary+0x140/0x150
 [<0000000000f5d2ae>] restart_int_handler+0x6e/0x90

Mark arch_cpu_idle() noinstr like all other architectures with
CONFIG_ARCH_WANTS_NO_INSTR (should) have it to fix this.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-02-09 20:11:22 +01:00
Heiko Carstens
c01016299d s390/idle: move idle time accounting to account_idle_time_irq()
There is no reason to do idle time accounting in arch_cpu_idle().
Do idle time accounting in account_idle_time_irq(), where it belongs
to. The accounted values don't change between account_idle_time_irq() and
arch_cpu_idle(); so the result is the same.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-02-09 20:11:22 +01:00
Alexander Gordeev
bb1520d581 s390/mm: start kernel with DAT enabled
The setup of the kernel virtual address space is spread
throughout the sources, boot stages and config options
like this:

1. The available physical memory regions are queried
   and stored as mem_detect information for later use
   in the decompressor.

2. Based on the physical memory availability the virtual
   memory layout is established in the decompressor;

3. If CONFIG_KASAN is disabled the kernel paging setup
   code populates kernel pgtables and turns DAT mode on.
   It uses the information stored at step [1].

4. If CONFIG_KASAN is enabled the kernel early boot
   kasan setup populates kernel pgtables and turns DAT
   mode on. It uses the information stored at step [1].

   The kasan setup creates early_pg_dir directory and
   directly overwrites swapper_pg_dir entries to make
   shadow memory pages available.

Move the kernel virtual memory setup to the decompressor
and start the kernel with DAT turned on right from the
very first istruction. That completely eliminates the
boot phase when the kernel runs in DAT-off mode, simplies
the overall design and consolidates pgtables setup.

The identity mapping is created in the decompressor, while
kasan shadow mappings are still created by the early boot
kernel code.

Share with decompressor the existing kasan memory allocator.
It decreases the size of a newly requested memory block from
pgalloc_pos and ensures that kernel image is not overwritten.
pgalloc_low and pgalloc_pos pointers are made preserved boot
variables for that.

Use the bootdata infrastructure to setup swapper_pg_dir
and invalid_pg_dir directories used by the kernel later.
The interim early_pg_dir directory established by the
kasan initialization code gets eliminated as result.

As the kernel runs in DAT-on mode only the PSW_KERNEL_BITS
define gets PSW_MASK_DAT bit by default. Additionally, the
setup_lowcore_dat_off() and setup_lowcore_dat_on() routines
get merged, since there is no DAT-off mode stage anymore.

The memory mappings are created with RW+X protection that
allows the early boot code setting up all necessary data
and services for the kernel being booted. Just before the
paging is enabled the memory protection is changed to
RO+X for text, RO+NX for read-only data and RW+NX for
kernel data and the identity mapping.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-01-13 14:15:05 +01:00
Peter Zijlstra
89b3098703 arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled
Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.

However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.

Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org
2023-01-13 11:48:15 +01:00
Nicholas Piggin
c89970202a cputime: remove cputime_to_nsecs fallback
The archs that use cputime_to_nsecs() internally provide their own
definition and don't need the fallback. cputime_to_usecs() unused except
in this fallback, and is not defined anywhere.

This removes the final remnant of the cputime_t code from the kernel.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/r/20221220070705.2958959-1-npiggin@gmail.com
2022-12-27 12:52:17 +01:00
Heiko Carstens
eba8e1af5a s390/time,idle: get rid of unsigned long long
Get rid of unsigned long long, and use unsigned long instead
everywhere. The usage of unsigned long long is a leftover from
31 bit kernel support.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-08 10:46:27 +01:00
Sven Schnelle
56e62a7370 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>
2021-01-19 12:29:26 +01:00
Heiko Carstens
8d93b70118 s390/idle: allow arch_cpu_idle() to be kprobed
Remove NOKPROBE_SYMBOL() for arch_cpu_idle(). This might have made
sense when enabled_wait() (aka arch_cpu_idle()) was called from
udelay.
But now there shouldn't be a reason why s390 should be the only
architecture which doesn't allow arch_cpu_idle() to be probed.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-12-16 14:55:50 +01:00
Heiko Carstens
7494755a9a s390/idle: remove raw_local_irq_save()/restore() from arch_cpu_idle()
arch_cpu_idle() gets called with interrupts disabled,
and psw_idle() returns with interrupts disabled.
No reason to use raw_local_irq_save() / restore().

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-12-16 14:55:49 +01:00
Heiko Carstens
44292c8684 s390/idle: merge enabled_wait() and arch_cpu_idle()
The only caller of enabled_wait() besides arch_cpu_idle() was
udelay(). Since that call doesn't exist anymore, merge enabled_wait()
and arch_cpu_idle().

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-12-16 14:55:49 +01:00
Peter Zijlstra
58c644ba51 sched/idle: Fix arch_cpu_idle() vs tracing
We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.

Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.

(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)

Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
2020-11-24 16:47:35 +01:00
Peter Zijlstra
ca589ea8d1 s390/idle: fix suspicious RCU usage
After commit eb1f00237a ("lockdep,trace: Expose tracepoints") the
lock tracepoints are visible to lockdep and RCU-lockdep is finding a
bunch more RCU violations that were previously hidden.

Switch the idle->seqcount over to using raw_write_*() to avoid the
lockdep annotation and thus the lock tracepoints.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-09-14 10:08:07 +02:00
Peter Zijlstra
9864f5b594 cpuidle: Move trace_cpu_idle() into generic code
Remove trace_cpu_idle() from the arch_cpu_idle() implementations and
put it in the generic code, right before disabling RCU. Gets rid of
more trace_*_rcuidle() users.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.428433395@infradead.org
2020-08-26 12:41:54 +02:00
Sven Schnelle
6589c93f99 s390: add trace events for idle enter/exit
Helpful for debugging.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-07-10 15:08:27 +02:00
Sven Schnelle
0b0ed657fe s390: remove critical section cleanup from entry.S
The current code is rather complex and caused a lot of subtle
and hard to debug bugs in the past. Simplify the code by calling
the system_call handler with interrupts disabled, save
machine state, and re-enable them later.

This requires significant changes to the machine check handling code
as well. When the machine check interrupt arrived while being in kernel
mode the new code will signal pending machine checks with a SIGP external
call. When userspace was interrupted, the handler will switch to the
kernel stack and directly execute s390_handle_mcck().

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-05-28 12:21:54 +02:00
Heiko Carstens
3d7efa4edd s390/idle: fix cpu idle time calculation
The idle time reported in /proc/stat sometimes incorrectly contains
huge values on s390. This is caused by a bug in arch_cpu_idle_time().

The kernel tries to figure out when a different cpu entered idle by
accessing its per-cpu data structure. There is an ordering problem: if
the remote cpu has an idle_enter value which is not zero, and an
idle_exit value which is zero, it is assumed it is idle since
"now". The "now" timestamp however is taken before the idle_enter
value is read.

Which in turn means that "now" can be smaller than idle_enter of the
remote cpu. Unconditionally subtracting idle_enter from "now" can thus
lead to a negative value (aka large unsigned value).

Fix this by moving the get_tod_clock() invocation out of the
loop. While at it also make the code a bit more readable.

A similar bug also exists for show_idle_time(). Fix this is as well.

Cc: <stable@vger.kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-10-31 17:26:48 +01:00
Greg Kroah-Hartman
b24413180f 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>
2017-11-02 11:10:55 +01:00
Ingo Molnar
32ef5517c2 sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>
Introduce a trivial, mostly empty <linux/sched/cputime.h> header
to prepare for the moving of cputime functionality out of sched.h.

Update all code that relies on these facilities.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:39 +01:00
Linus Torvalds
ff47d8c050 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Martin Schwidefsky:

 - New entropy generation for the pseudo random number generator.

 - Early boot printk output via sclp to help debug crashes on boot. This
   needs to be enabled with a kernel parameter.

 - Add proper no-execute support with a bit in the page table entry.

 - Bug fixes and cleanups.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (65 commits)
  s390/syscall: fix single stepped system calls
  s390/zcrypt: make ap_bus explicitly non-modular
  s390/zcrypt: Removed unneeded debug feature directory creation.
  s390: add missing "do {} while (0)" loop constructs to multiline macros
  s390/mm: add cond_resched call to kernel page table dumper
  s390: get rid of MACHINE_HAS_PFMF and MACHINE_HAS_HPAGE
  s390/mm: make memory_block_size_bytes available for !MEMORY_HOTPLUG
  s390: replace ACCESS_ONCE with READ_ONCE
  s390: Audit and remove any remaining unnecessary uses of module.h
  s390: mm: Audit and remove any unnecessary uses of module.h
  s390: kernel: Audit and remove any unnecessary uses of module.h
  s390/kdump: Use "LINUX" ELF note name instead of "CORE"
  s390: add no-execute support
  s390: report new vector facilities
  s390: use correct input data address for setup_randomness
  s390/sclp: get rid of common response code handling
  s390/sclp: don't add new lines to each printed string
  s390/sclp: make early sclp code readable
  s390/sclp: disable early sclp code as soon as the base sclp driver is active
  s390/sclp: move early printk code to drivers
  ...
2017-02-22 10:20:04 -08:00
Christian Borntraeger
187b5f41b4 s390: replace ACCESS_ONCE with READ_ONCE
Remove the last places of ACCESS_ONCE in s390 code.

Signed-off-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>
2017-02-17 07:40:46 +01:00
Frederic Weisbecker
42b425b336 s390, sched/cputime: Make arch_cpu_idle_time() to return nsecs
This way we don't need to deal with cputime_t details from the core code.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-32-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01 09:14:03 +01:00
Frederic Weisbecker
fb8b049c98 sched/cputime: Push time to account_system_time() in nsecs
This is one more step toward converting cputime accounting to pure nsecs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-25-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01 09:13:58 +01:00
Frederic Weisbecker
18b43a9bd7 sched/cputime: Push time to account_idle_time() in nsecs
This is one more step toward converting cputime accounting to pure nsecs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-24-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01 09:13:57 +01:00
Frederic Weisbecker
1ce2180498 s390/idle: convert open coded idle time seqcount
s390 uses open coded seqcount to synchronize idle time accounting.
Lets consolidate it with the standard API.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-12-08 09:42:32 +01:00
Heiko Carstens
200e7c0ffb s390/idle: add missing irq off lockdep annotation
psw_idle() returns with interrupts disabled, so we should add the
missing annotation.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-12-08 09:42:31 +01:00
Heiko Carstens
7a5388de5c s390/kprobes: make use of NOKPROBE_SYMBOL()
Use NOKPROBE_SYMBOL() instead of __kprobes annotation.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-27 13:27:28 +01:00
Linus Torvalds
0429fbc0bd Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu consistent-ops changes from Tejun Heo:
 "Way back, before the current percpu allocator was implemented, static
  and dynamic percpu memory areas were allocated and handled separately
  and had their own accessors.  The distinction has been gone for many
  years now; however, the now duplicate two sets of accessors remained
  with the pointer based ones - this_cpu_*() - evolving various other
  operations over time.  During the process, we also accumulated other
  inconsistent operations.

  This pull request contains Christoph's patches to clean up the
  duplicate accessor situation.  __get_cpu_var() uses are replaced with
  with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

  Unfortunately, the former sometimes is tricky thanks to C being a bit
  messy with the distinction between lvalues and pointers, which led to
  a rather ugly solution for cpumask_var_t involving the introduction of
  this_cpu_cpumask_var_ptr().

  This converts most of the uses but not all.  Christoph will follow up
  with the remaining conversions in this merge window and hopefully
  remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
  irqchip: Properly fetch the per cpu offset
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
  ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
  Revert "powerpc: Replace __get_cpu_var uses"
  percpu: Remove __this_cpu_ptr
  clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
  sparc: Replace __get_cpu_var uses
  avr32: Replace __get_cpu_var with __this_cpu_write
  blackfin: Replace __get_cpu_var uses
  tile: Use this_cpu_ptr() for hardware counters
  tile: Replace __get_cpu_var uses
  powerpc: Replace __get_cpu_var uses
  alpha: Replace __get_cpu_var
  ia64: Replace __get_cpu_var uses
  s390: cio driver &__get_cpu_var replacements
  s390: Replace __get_cpu_var uses
  mips: Replace __get_cpu_var uses
  MIPS: Replace __get_cpu_var uses in FPU emulator.
  arm: Replace __this_cpu_ptr with raw_cpu_ptr
  ...
2014-10-15 07:48:18 +02:00
Martin Schwidefsky
b5f87f15e2 s390/idle: consolidate idle functions and definitions
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 <schwidefsky@de.ibm.com>
2014-10-09 09:14:03 +02:00