s390/wti: Introduce infrastructure for warning track interrupt

The warning-track interrupt (wti) provides a notification that the
receiving CPU will be pre-empted from its physical CPU within a shor

s390/wti: Introduce infrastructure for warning track interrupt

The warning-track interrupt (wti) provides a notification that the
receiving CPU will be pre-empted from its physical CPU within a short
time frame. This time frame is called grace period and depends on the
machine type. Giving up the CPU on time may prevent a task to get stuck
while holding a resource.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

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s390: Replace S390_lowcore by get_lowcore()

Replace all S390_lowcore usages in arch/s390/ by get_lowcore().

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ib

s390: Replace S390_lowcore by get_lowcore()

Replace all S390_lowcore usages in arch/s390/ by get_lowcore().

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

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s390/irq: Set CIF_NOHZ_DELAY in do_io_irq()

Both do_airq_interrupt() and do_io_interrupt() set
CIF_NOHZ_DELAY. Move it to do_io_irq() to simplify
the code.

Reviewed-by: Heiko Carstens <hca@linux.ib

s390/irq: Set CIF_NOHZ_DELAY in do_io_irq()

Both do_airq_interrupt() and do_io_interrupt() set
CIF_NOHZ_DELAY. Move it to do_io_irq() to simplify
the code.

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>

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s390/irq,nmi: Include <asm/vtime.h> header directly

update_timer_sys() and update_timer_mcck() are inlines used for
CPU time accounting from the interrupt and machine-check handlers.
These routines

s390/irq,nmi: Include <asm/vtime.h> header directly

update_timer_sys() and update_timer_mcck() are inlines used for
CPU time accounting from the interrupt and machine-check handlers.
These routines are specific to s390 architecture, but included
via <linux/vtime.h> header implicitly. Avoid the extra loop and
include <asm/vtime.h> header directly.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/3fb696637c0eb7e9d6ffd6cbf9e647d7c5986b3d.1712760275.git.agordeev@linux.ibm.com

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s390/ctlreg: add local and system prefix to some functions

Add local and system prefix to some functions to clarify they change
control register contents on either the local CPU or the on all CPUs.

s390/ctlreg: add local and system prefix to some functions

Add local and system prefix to some functions to clarify they change
control register contents on either the local CPU or the on all CPUs.

This results in the following API:

Two defines which load and save multiple control registers.
The defines correlate with the following C prototypes:

void __local_ctl_load(unsigned long *, unsigned int cr_low, unsigned int cr_high);
void __local_ctl_store(unsigned long *, unsigned int cr_low, unsigned int cr_high);

Two functions which locally set or clear one bit for a specified
control register:

void local_ctl_set_bit(unsigned int cr, unsigned int bit);
void local_ctl_clear_bit(unsigned int cr, unsigned int bit);

Two functions which set or clear one bit for a specified control
register on all CPUs:

void system_ctl_set_bit(unsigned int cr, unsigned int bit);
void system_ctl_clear_bit(unsigend int cr, unsigned int bit);

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

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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 cl

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>

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s390/irq: utilize RCU instead of irq_lock_sparse() in show_msi_interrupt()

As demonstrated by commit 74bdf7815dfb ("genirq: Speedup
show_interrupts()"), irq_desc can be accessed safely in RCU read s

s390/irq: utilize RCU instead of irq_lock_sparse() in show_msi_interrupt()

As demonstrated by commit 74bdf7815dfb ("genirq: Speedup
show_interrupts()"), irq_desc can be accessed safely in RCU read section.

Hence here resorting to rcu read lock to get rid of irq_lock_sparse().

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Link: https://lore.kernel.org/r/20220422100212.22666-1-kernelfans@gmail.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/irq: use assignment instead of cast

Change struct ext_code to contain a union which allows to simply
assign the int_code instead of using a cast.

In order to keep the patch small the anonymous

s390/irq: use assignment instead of cast

Change struct ext_code to contain a union which allows to simply
assign the int_code instead of using a cast.

In order to keep the patch small the anonymous union is embedded
within the existing struct instead of changing the struct ext_code to
a union.

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

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s390/entry: fix duplicate tracking of irq nesting level

In the current code, when exiting from idle, rcu_irq_enter() is
called twice during irq entry:

irq_entry_enter()-> rcu_irq_enter()
irq_enter(

s390/entry: fix duplicate tracking of irq nesting level

In the current code, when exiting from idle, rcu_irq_enter() is
called twice during irq entry:

irq_entry_enter()-> rcu_irq_enter()
irq_enter() -> rcu_irq_enter()

This may lead to wrong results from rcu_is_cpu_rrupt_from_idle()
because of a wrong dynticks nmi nesting count. Fix this by only
calling irq_enter_rcu().

Cc: <stable@vger.kernel.org> # 5.12+
Reported-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 56e62a737028 ("s390: convert to generic entry")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390: add support for BEAR enhancement facility

The Breaking-Event-Address-Register (BEAR) stores the address of the
last breaking event instruction. Breaking events are usually instructions
that ch

s390: add support for BEAR enhancement facility

The Breaking-Event-Address-Register (BEAR) stores the address of the
last breaking event instruction. Breaking events are usually instructions
that change the program flow - for example branches, and instructions
that modify the address in the PSW like lpswe. This is useful for debugging
wild branches, because one could easily figure out where the wild branch
was originating from.

What is problematic is that lpswe is considered a breaking event, and
therefore overwrites BEAR on kernel exit. The BEAR enhancement facility
adds new instructions that allow to save/restore BEAR and also an lpswey
instruction that doesn't cause a breaking event. So we can save BEAR on
kernel entry and restore it on exit to user space.

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

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s390: replace deprecated CPU-hotplug functions

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpu

s390: replace deprecated CPU-hotplug functions

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-5-bigeasy@linutronix.de
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/irq: use call_on_stack() macro

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/irq: simplify on_async_stack()

Make on_async_stack() a bit more readable, even though as usual it
depends if one considers "!!!" readable or not.
At least the new construct to check if the asyn

s390/irq: simplify on_async_stack()

Make on_async_stack() a bit more readable, even though as usual it
depends if one considers "!!!" readable or not.
At least the new construct to check if the async stack is in use or
not is a bit shorter and generates slightly better code.

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>

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s390/irq: inline do_softirq_own_stack()

Move do_softirq_own_stack() to proper header file so it can be
inlined; saving a few cycles.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by:

s390/irq: inline do_softirq_own_stack()

Move do_softirq_own_stack() to proper header file so it can be
inlined; saving a few cycles.

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>

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s390/irq: simplify do_softirq_own_stack()

do_softirq_own_stack() is always called from task context and
therefore it is not necessary to check if the async stack is
currently used.
Remove the check

s390/irq: simplify do_softirq_own_stack()

do_softirq_own_stack() is always called from task context and
therefore it is not necessary to check if the async stack is
currently used.
Remove the check and directly switch to async stack.

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>

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s390: use struct tpi_info in lowcore.h

Signed-off-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/irq: add union/struct to access external interrupt parameters

gcc-11 warns:

arch/s390/kernel/irq.c: In function do_ext_irq:
arch/s390/kernel/irq.c:175:9: warning: memcpy reading 4 bytes from a

s390/irq: add union/struct to access external interrupt parameters

gcc-11 warns:

arch/s390/kernel/irq.c: In function do_ext_irq:
arch/s390/kernel/irq.c:175:9: warning: memcpy reading 4 bytes from a region of size 0 [-Wstringop-overread]
175 | memcpy(&regs->int_code, &S390_lowcore.ext_cpu_addr, 4);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by adding a struct for int_code to struct lowcore.

Signed-off-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>

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s390/irq: fix reading of ext_params2 field from lowcore

The contents of the ext_params2 field of the lowcore should just be
copied to the pt_regs structure, not dereferenced.

Fixes crashes / progra

s390/irq: fix reading of ext_params2 field from lowcore

The contents of the ext_params2 field of the lowcore should just be
copied to the pt_regs structure, not dereferenced.

Fixes crashes / program check loops like this:

Krnl PSW : 0404c00180000000 00000000d6d02b3c (do_ext_irq+0x74/0x170)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
Krnl GPRS: 0000000000000000 80000000000b974e 00000000d71abee0 00000000d71abee0
0000000080030000 000000000000000f 0000000000000000 0000000000000000
0000000000000001 00000380000bf918 00000000d73ef780 00000380000bf518
0000000080348000 00000000d6d13350 00000000d6d02b1e 00000380000bf428
Krnl Code: 00000000d6d02b2e: 58100080 l %r1,128
00000000d6d02b32: 5010b0a4 st %r1,164(%r11)
#00000000d6d02b36: e31001b80104 lg %r1,4536
>00000000d6d02b3c: e31010000004 lg %r1,0(%r1)
00000000d6d02b42: e310b0a80024 stg %r1,168(%r11)
00000000d6d02b48: c01000242270 larl %r1,00000000d7187028
00000000d6d02b4e: d5071000b010 clc 0(8,%r1),16(%r11)
00000000d6d02b54: a784001b brc 8,00000000d6d02b8a
Call Trace:
[<00000000d6d02b3c>] do_ext_irq+0x74/0x170
[<00000000d6d0ea5c>] ext_int_handler+0xc4/0xf4
[<00000000d621d266>] die+0x106/0x188
[<00000000d62305b8>] do_no_context+0xc8/0x100
[<00000000d6d02790>] __do_pgm_check+0xe0/0x1f0
[<00000000d6d0e950>] pgm_check_handler+0x118/0x160
[<00000000d6d02b3c>] do_ext_irq+0x74/0x170
[<00000000d6d0ea5c>] ext_int_handler+0xc4/0xf4
[<00000000d621d266>] die+0x106/0x188
[<00000000d62305b8>] do_no_context+0xc8/0x100
[<00000000d6d02790>] __do_pgm_check+0xe0/0x1f0
[<00000000d6d0e950>] pgm_check_handler+0x118/0x160
[<00000000d6d02b3c>] do_ext_irq+0x74/0x170
[<00000000d6d0ea5c>] ext_int_handler+0xc4/0xf4
[<0000000000000000>] 0x0
[<00000000d6d0e57a>] default_idle_call+0x42/0x110
[<00000000d629856e>] do_idle+0xce/0x160
[<00000000d62987be>] cpu_startup_entry+0x36/0x40
[<00000000d621f2f2>] smp_start_secondary+0x82/0x88

Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Fixes: 56e62a737028 ("s390: convert to generic entry")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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softirq: Move do_softirq_own_stack() to generic asm header

To avoid include recursion hell move the do_softirq_own_stack() related
content into a generic asm header and include it from all places in

softirq: Move do_softirq_own_stack() to generic asm header

To avoid include recursion hell move the do_softirq_own_stack() related
content into a generic asm header and include it from all places in arch/
which need the prototype.

This allows architectures to provide an inline implementation of
do_softirq_own_stack() without introducing a lot of #ifdeffery all over the
place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210210002513.289960691@linutronix.de

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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

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>

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s390/irq: Use irq_desc_kstat_cpu() in show_msi_interrupt()

The irq descriptor is already there, no need to look it up again.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Heiko Cars

s390/irq: Use irq_desc_kstat_cpu() in show_msi_interrupt()

The irq descriptor is already there, no need to look it up again.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20201210194043.769108348@linutronix.de

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s390/irq: make init_ext_interrupts static

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

s390/irq: replace setup_irq() by request_irq()

request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.

Per tglx[1], setup_irq() existed in o

s390/irq: replace setup_irq() by request_irq()

request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Message-Id: <20200304005049.5291-1-afzal.mohd.ma@gmail.com>
[heiko.carstens@de.ibm.com: replace pr_err with panic]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

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s390/unwind: introduce stack unwind API

Rework the dump_trace() stack unwinder interface to support different
unwinding algorithms. The new interface looks like this:

struct unwind_state state;
u

s390/unwind: introduce stack unwind API

Rework the dump_trace() stack unwinder interface to support different
unwinding algorithms. The new interface looks like this:

struct unwind_state state;
unwind_for_each_frame(&state, task, regs, start_stack)
do_something(state.sp, state.ip, state.reliable);

The unwind_bc.c file contains the implementation for the classic
back-chain unwinder.

One positive side effect of the new code is it now handles ftraced
functions gracefully. It prints the real name of the return function
instead of 'return_to_handler'.

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

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s390/pci: gather statistics for floating vs directed irqs

Gather statistics to distinguish floating and directed interrupts.

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Marti

s390/pci: gather statistics for floating vs directed irqs

Gather statistics to distinguish floating and directed interrupts.

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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