linux-toradex.git/arch/sparc/kernel/process_64.c, branch v6.7

Merge tag 'tty-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2023-09-01T16:38:00+00:00

Pull tty/serial driver updates from Greg KH:
 "Here is the big set of tty and serial driver changes for 6.6-rc1.

  Lots of cleanups in here this cycle, and some driver updates. Short
  summary is:

   - Jiri's continued work to make the tty code and apis be a bit more
     sane with regards to modern kernel coding style and types

   - cpm_uart driver updates

   - n_gsm updates and fixes

   - meson driver updates

   - sc16is7xx driver updates

   - 8250 driver updates for different hardware types

   - qcom-geni driver fixes

   - tegra serial driver change

   - stm32 driver updates

   - synclink_gt driver cleanups

   - tty structure size reduction

  All of these have been in linux-next this week with no reported
  issues. The last bit of cleanups from Jiri and the tty structure size
  reduction came in last week, a bit late but as they were just style
  changes and size reductions, I figured they should get into this merge
  cycle so that others can work on top of them with no merge conflicts"

* tag 'tty-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (199 commits)
  tty: shrink the size of struct tty_struct by 40 bytes
  tty: n_tty: deduplicate copy code in n_tty_receive_buf_real_raw()
  tty: n_tty: extract ECHO_OP processing to a separate function
  tty: n_tty: unify counts to size_t
  tty: n_tty: use u8 for chars and flags
  tty: n_tty: simplify chars_in_buffer()
  tty: n_tty: remove unsigned char casts from character constants
  tty: n_tty: move newline handling to a separate function
  tty: n_tty: move canon handling to a separate function
  tty: n_tty: use MASK() for masking out size bits
  tty: n_tty: make n_tty_data::num_overrun unsigned
  tty: n_tty: use time_is_before_jiffies() in n_tty_receive_overrun()
  tty: n_tty: use 'num' for writes' counts
  tty: n_tty: use output character directly
  tty: n_tty: make flow of n_tty_receive_buf_common() a bool
  Revert "tty: serial: meson: Add a earlycon for the T7 SoC"
  Documentation: devices.txt: Fix minors for ttyCPM*
  Documentation: devices.txt: Remove ttySIOC*
  Documentation: devices.txt: Remove ttyIOC*
  serial: 8250_bcm7271: improve bcm7271 8250 port
  ...

nmi_backtrace: allow excluding an arbitrary CPU

2023-08-18T17:19:00+00:00

The APIs that allow backtracing across CPUs have always had a way to
exclude the current CPU.  This convenience means callers didn't need to
find a place to allocate a CPU mask just to handle the common case.

Let's extend the API to take a CPU ID to exclude instead of just a
boolean.  This isn't any more complex for the API to handle and allows the
hardlockup detector to exclude a different CPU (the one it already did a
trace for) without needing to find space for a CPU mask.

Arguably, this new API also encourages safer behavior.  Specifically if
the caller wants to avoid tracing the current CPU (maybe because they
already traced the current CPU) this makes it more obvious to the caller
that they need to make sure that the current CPU ID can't change.

[akpm@linux-foundation.org: fix trigger_allbutcpu_cpu_backtrace() stub]
Link: https://lkml.kernel.org/r/20230804065935.v4.1.Ia35521b91fc781368945161d7b28538f9996c182@changeid
Signed-off-by: Douglas Anderson 
Acked-by: Michal Hocko 
Cc: kernel test robot 
Cc: Lecopzer Chen 
Cc: Petr Mladek 
Cc: Pingfan Liu 
Signed-off-by: Andrew Morton

tty: sysrq: switch sysrq handlers from int to u8

2023-07-25T17:21:03+00:00

The passed parameter to sysrq handlers is a key (a character). So change
the type from 'int' to 'u8'. Let it specifically be 'u8' for two
reasons:
* unsigned: unsigned values come from the upper layers (devices) and the
  tty layer assumes unsigned on most places, and
* 8-bit: as that what's supposed to be one day in all the layers built
  on the top of tty. (Currently, we use mostly 'unsigned char' and
  somewhere still only 'char'. (But that also translates to the former
  thanks to -funsigned-char.))

Signed-off-by: Jiri Slaby (SUSE) 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Huacai Chen 
Cc: WANG Xuerui 
Cc: Thomas Bogendoerfer 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Christophe Leroy 
Cc: "David S. Miller" 
Cc: Maarten Lankhorst 
Cc: Maxime Ripard 
Cc: Thomas Zimmermann 
Cc: David Airlie 
Cc: Daniel Vetter 
Cc: Jason Wessel 
Cc: Daniel Thompson 
Cc: Douglas Anderson 
Cc: "Rafael J. Wysocki" 
Cc: Len Brown 
Cc: Pavel Machek 
Cc: "Paul E. McKenney" 
Cc: Frederic Weisbecker 
Cc: Neeraj Upadhyay 
Cc: Joel Fernandes 
Cc: Josh Triplett 
Cc: Boqun Feng 
Cc: Steven Rostedt 
Cc: Mathieu Desnoyers 
Cc: Lai Jiangshan 
Cc: Zqiang 
Acked-by: Thomas Zimmermann  # DRM
Acked-by: WANG Xuerui  # loongarch
Acked-by: Paul E. McKenney 
Acked-by: Daniel Thompson 
Link: https://lore.kernel.org/r/20230712081811.29004-3-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

sched/idle: Mark arch_cpu_idle_dead() __noreturn

2023-03-08T16:44:28+00:00

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 
Tested-by: Paul E. McKenney 
Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf

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

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"

sparc64: remove CONFIG_SET_FS support

2022-02-25T08:36:06+00:00

sparc64 uses address space identifiers to differentiate between kernel
and user space, using ASI_P for kernel threads but ASI_AIUS for normal
user space, with the option of changing between them.

As nothing really changes the ASI any more, just hardcode ASI_AIUS
everywhere. Kernel threads are not allowed to access __user pointers
anyway.

Signed-off-by: Arnd Bergmann

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

arch: remove compat_alloc_user_space

2021-09-08T22:32:35+00:00

All users of compat_alloc_user_space() and copy_in_user() have been
removed from the kernel, only a few functions in sparc remain that can be
changed to calling arch_copy_in_user() instead.

Link: https://lkml.kernel.org/r/20210727144859.4150043-7-arnd@kernel.org
Signed-off-by: Arnd Bergmann 
Reviewed-by: Christoph Hellwig 
Cc: Al Viro 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Christian Borntraeger 
Cc: Christoph Hellwig 
Cc: "David S. Miller" 
Cc: Eric Biederman 
Cc: Feng Tang 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: "James E.J. Bottomley" 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds