linux.git/arch/openrisc/kernel/process.c, branch v6.8

openrisc: Include cpu.h and switch_to.h for prototypes

2023-08-21T07:15:25+00:00

When compiling with W=1 enabling -Wmissing-prototypes the compiler
warns:

  arch/openrisc/kernel/process.c:100:6: error: no previous prototype for 'arch_cpu_idle' [-Werror=missing-prototypes]
  arch/openrisc/kernel/process.c:240:21: error: no previous prototype for '__switch_to' [-Werror=missing-prototypes]

Fix these by adding the approrpiate header files to process.c which
brings in the prototype definitions.

Reported-by: Arnd Bergmann 
Closes: https://lore.kernel.org/linux-kernel/20230810141947.1236730-17-arnd@kernel.org/
Signed-off-by: Stafford Horne

openrisc: Add prototype for show_registers to processor.h

2023-08-21T07:15:18+00:00

When compiling with W=1 enabling -Wmissing-prototypes the compiler
warns:

  arch/openrisc/kernel/traps.c:67:6: error: no previous prototype for 'show_registers' [-Werror=missing-prototypes]

Fix by adding the prototype to the appropriate header file and including
the header file in the appropriate C files.

Reported-by: Arnd Bergmann 
Closes: https://lore.kernel.org/linux-kernel/20230810141947.1236730-17-arnd@kernel.org/
Signed-off-by: Stafford Horne

arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled

2023-01-13T10:48:15+00:00

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) 
Signed-off-by: Ingo Molnar 
Tested-by: Tony Lindgren 
Tested-by: Ulf Hansson 
Reviewed-by: Gautham R. Shenoy 
Acked-by: Mark Rutland  [arm64]
Acked-by: Rafael J. Wysocki 
Acked-by: Guo Ren 
Acked-by: Frederic Weisbecker 
Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org

kernel: exit: cleanup release_thread()

2022-09-12T04:55:07+00:00

Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.

Link: https://lkml.kernel.org/r/20220819014406.32266-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Acked-by: Guo Ren 				[csky]
Acked-by: Russell King (Oracle) 
Acked-by: Geert Uytterhoeven 
Acked-by: Brian Cain 
Acked-by: Michael Ellerman 			[powerpc]
Acked-by: Stafford Horne 			[openrisc]
Acked-by: Catalin Marinas 		[arm64]
Acked-by: Huacai Chen 			[LoongArch]
Cc: Alexander Gordeev 
Cc: Anton Ivanov 
Cc: Borislav Petkov 
Cc: Christian Borntraeger 
Cc: Christophe Leroy 
Cc: Chris Zankel 
Cc: Dave Hansen 
Cc: "David S. Miller" 
Cc: Dinh Nguyen 
Cc: Guo Ren  [csky]
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: Ingo Molnar 
Cc: Ivan Kokshaysky 
Cc: James Bottomley 
Cc: Johannes Berg 
Cc: Jonas Bonn 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michal Simek 
Cc: Nicholas Piggin 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Richard Henderson 
Cc: Richard Weinberger 
Cc: Rich Felker 
Cc: Stefan Kristiansson 
Cc: Sven Schnelle 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Vineet Gupta 
Cc: Will Deacon 
Cc: Xuerui Wang 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton

Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-06-03T23:03:05+00:00

Pull kthread updates from Eric Biederman:
 "This updates init and user mode helper tasks to be ordinary user mode
  tasks.

  Commit 40966e316f86 ("kthread: Ensure struct kthread is present for
  all kthreads") caused init and the user mode helper threads that call
  kernel_execve to have struct kthread allocated for them. This struct
  kthread going away during execve in turned made a use after free of
  struct kthread possible.

  Here, commit 343f4c49f243 ("kthread: Don't allocate kthread_struct for
  init and umh") is enough to fix the use after free and is simple
  enough to be backportable.

  The rest of the changes pass struct kernel_clone_args to clean things
  up and cause the code to make sense.

  In making init and the user mode helpers tasks purely user mode tasks
  I ran into two complications. The function task_tick_numa was
  detecting tasks without an mm by testing for the presence of
  PF_KTHREAD. The initramfs code in populate_initrd_image was using
  flush_delayed_fput to ensuere the closing of all it's file descriptors
  was complete, and flush_delayed_fput does not work in a userspace
  thread.

  I have looked and looked and more complications and in my code review
  I have not found any, and neither has anyone else with the code
  sitting in linux-next"

* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  sched: Update task_tick_numa to ignore tasks without an mm
  fork: Stop allowing kthreads to call execve
  fork: Explicitly set PF_KTHREAD
  init: Deal with the init process being a user mode process
  fork: Generalize PF_IO_WORKER handling
  fork: Explicity test for idle tasks in copy_thread
  fork: Pass struct kernel_clone_args into copy_thread
  kthread: Don't allocate kthread_struct for init and umh

openrisc: Allow power off handler overriding

2022-05-23T08:15:50+00:00

The OpenRISC platform always defines a default pm_power_off hanlder
which is only useful for simulators.  Having this set also means power
management drivers like syscon-power are not able to wire in their own
pm_power_off handlers.

Fix this by not setting the pm_power_off handler by default and fallback
to the simulator power off handler if no handler is set.

This has been tested with a new OpenRISC virt platform I am working on
for QEMU.

  https://github.com/stffrdhrn/qemu/commits/or1k-virt

Cc: Jason A. Donenfeld 
Signed-off-by: Stafford Horne

openrisc: define nop command for simulator reboot

2022-05-23T08:15:49+00:00

The simulator defines `l.nop 1` for shutdown, but doesn't have anything
for reboot. Use 13 for this, which is currently unused, dubbed
`NOP_REBOOT`.

Cc: Stafford Horne 
Cc: Peter Maydell 
Link: https://lore.kernel.org/all/YmnaDUpVI5ihgvg6@zx2c4.com/
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Stafford Horne

fork: Generalize PF_IO_WORKER handling

2022-05-07T14:01:59+00:00

Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.

The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.

The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size".  These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().

Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman"

fork: Pass struct kernel_clone_args into copy_thread

2022-05-07T14:01:48+00:00

With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.

The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.

Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.

v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman"

sched: Add wrapper for get_wchan() to keep task blocked

2021-10-15T09:25:14+00:00

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zijlstra 
Signed-off-by: Kees Cook 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Geert Uytterhoeven 
Acked-by: Russell King (Oracle)  [arm]
Tested-by: Mark Rutland  [arm64]
Link: https://lkml.kernel.org/r/20211008111626.332092234@infradead.org