linux-toradex.git/include/linux/reboot.h, branch v4.14-rc5

kernel/reboot.c: add orderly_reboot for graceful reboot

2015-04-15T23:35:23+00:00

The kernel has orderly_poweroff which allows the kernel to initiate a
graceful shutdown of userspace, by running /sbin/poweroff.  This adds
orderly_reboot that will cause userspace to shut itself down by calling
/sbin/reboot.

This will be used for shutdown initiated by a system controller on
platforms that do not use ACPI.

orderly_reboot() should be used when the system wants to allow userspace
to gracefully shut itself down.  For cases where the system may imminently
catch on fire, the existing emergency_restart() provides an immediate
reboot without involving userspace.

Signed-off-by: Joel Stanley 
Cc: Fabian Frederick 
Cc: Benjamin Herrenschmidt 
Cc: Michael Ellerman 
Cc: Rusty Russell 
Cc: Jeremy Kerr 
Cc: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel: add support for kernel restart handler call chain

2014-09-26T07:00:06+00:00

Various drivers implement architecture and/or device specific means to
restart (reset) the system.  Various mechanisms have been implemented to
support those schemes.  The best known mechanism is arm_pm_restart, which
is a function pointer to be set either from platform specific code or from
drivers.  Another mechanism is to use hardware watchdogs to issue a reset;
this mechanism is used if there is no other method available to reset a
board or system.  Two examples are alim7101_wdt, which currently uses the
reboot notifier to trigger a reset, and moxart_wdt, which registers the
arm_pm_restart function.

The existing mechanisms have a number of drawbacks.  Typically only one
scheme to restart the system is supported (at least if arm_pm_restart is
used).  At least in theory there can be multiple means to restart the
system, some of which may be less desirable (for example one mechanism may
only reset the CPU, while another may reset the entire system).  Using
arm_pm_restart can also be racy if the function pointer is set from a
driver, as the driver may be in the process of being unloaded when
arm_pm_restart is called.  Using the reboot notifier is always racy, as it
is unknown if and when other functions using the reboot notifier have
completed execution by the time the watchdog fires.

Introduce a system restart handler call chain to solve the described
problems.  This call chain is expected to be executed from the
architecture specific machine_restart() function.  Drivers providing
system restart functionality (such as the watchdog drivers mentioned
above) are expected to register with this call chain.  By using the
priority field in the notifier block, callers can control restart handler
execution sequence and thus ensure that the restart handler with the
optimal restart capabilities for a given system is called first.

Signed-off-by: Guenter Roeck 
Acked-by: Catalin Marinas 
Acked-by: Heiko Stuebner 
Cc: Russell King 
Cc: Wim Van Sebroeck 
Cc: Maxime Ripard 
Cc: Will Deacon 
Cc: Arnd Bergmann 
Cc: Jonas Jensen 
Cc: Randy Dunlap 
Cc: Steven Rostedt 
Cc: Ingo Molnar 
Cc: Dmitry Eremin-Solenikov 
Cc: David Woodhouse 
Cc: Tomasz Figa 
Signed-off-by: Andrew Morton

x86: Remove the PCI reboot method from the default chain

2014-04-16T06:56:09+00:00

Steve reported a reboot hang and bisected it back to this commit:

  a4f1987e4c54 x86, reboot: Add EFI and CF9 reboot methods into the default list

He heroically tested all reboot methods and found the following:

  reboot=t       # triple fault                  ok
  reboot=k       # keyboard ctrl                 FAIL
  reboot=b       # BIOS                          ok
  reboot=a       # ACPI                          FAIL
  reboot=e       # EFI                           FAIL   [system has no EFI]
  reboot=p       # PCI 0xcf9                     FAIL

And I think it's pretty obvious that we should only try PCI 0xcf9 as a
last resort - if at all.

The other observation is that (on this box) we should never try
the PCI reboot method, but close with either the 'triple fault'
or the 'BIOS' (terminal!) reboot methods.

Thirdly, CF9_COND is a total misnomer - it should be something like
CF9_SAFE or CF9_CAREFUL, and 'CF9' should be 'CF9_FORCE' ...

So this patch fixes the worst problems:

 - it orders the actual reboot logic to follow the reboot ordering
   pattern - it was in a pretty random order before for no good
   reason.

 - it fixes the CF9 misnomers and uses BOOT_CF9_FORCE and
   BOOT_CF9_SAFE flags to make the code more obvious.

 - it tries the BIOS reboot method before the PCI reboot method.
   (Since 'BIOS' is a terminal reboot method resulting in a hang
    if it does not work, this is essentially equivalent to removing
    the PCI reboot method from the default reboot chain.)

 - just for the miraculous possibility of terminal (resulting
   in hang) reboot methods of triple fault or BIOS returning
   without having done their job, there's an ordering between
   them as well.

Reported-and-bisected-and-tested-by: Steven Rostedt 
Cc: Li Aubrey 
Cc: Linus Torvalds 
Cc: Matthew Garrett 
Link: http://lkml.kernel.org/r/20140404064120.GB11877@gmail.com
Signed-off-by: Ingo Molnar

kexec: migrate to reboot cpu

2013-12-19T03:04:50+00:00

Commit 1b3a5d02ee07 ("reboot: move arch/x86 reboot= handling to generic
kernel") moved reboot= handling to generic code.  In the process it also
removed the code in native_machine_shutdown() which are moving reboot
process to reboot_cpu/cpu0.

I guess that thought must have been that all reboot paths are calling
migrate_to_reboot_cpu(), so we don't need this special handling.  But
kexec reboot path (kernel_kexec()) is not calling
migrate_to_reboot_cpu() so above change broke kexec.  Now reboot can
happen on non-boot cpu and when INIT is sent in second kerneo to bring
up BP, it brings down the machine.

So start calling migrate_to_reboot_cpu() in kexec reboot path to avoid
this problem.

Bisected by WANG Chao.

Reported-by: Matthew Whitehead 
Reported-by: Dave Young 
Signed-off-by: Vivek Goyal 
Tested-by: Baoquan He 
Tested-by: WANG Chao 
Acked-by: H. Peter Anvin 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

reboot: move arch/x86 reboot= handling to generic kernel

2013-07-09T17:33:29+00:00

Merge together the unicore32, arm, and x86 reboot= command line
parameter handling.

Signed-off-by: Robin Holt 
Cc: H. Peter Anvin 
Cc: Russell King 
Cc: Guan Xuetao 
Cc: Russ Anderson 
Cc: Robin Holt 
Acked-by: Ingo Molnar 
Acked-by: Guan Xuetao 
Acked-by: Russell King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

reboot: arm: change reboot_mode to use enum reboot_mode

2013-07-09T17:33:29+00:00

Preparing to move the parsing of reboot= to generic kernel code forces
the change in reboot_mode handling to use the enum.

[akpm@linux-foundation.org: fix arch/arm/mach-socfpga/socfpga.c]
Signed-off-by: Robin Holt 
Cc: Russell King 
Cc: Russ Anderson 
Cc: Robin Holt 
Cc: H. Peter Anvin 
Cc: Guan Xuetao 
Acked-by: Russell King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

reboot: unicore32: prepare reboot_mode for moving to generic kernel code

2013-07-09T17:33:29+00:00

Prepare for the moving the parsing of reboot= to the generic kernel code
by making reboot_mode into a more generic form.

Signed-off-by: Robin Holt 
Cc: Guan Xuetao 
Cc: Russ Anderson 
Cc: Robin Holt 
Cc: Russell King 
Cc: H. Peter Anvin 
Acked-by: Guan Xuetao 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

reboot: x86: prepare reboot_mode for moving to generic kernel code

2013-07-09T17:33:29+00:00

Prepare for the moving the parsing of reboot= to the generic kernel code
by making reboot_mode into a more generic form.

Signed-off-by: Robin Holt 
Cc: H. Peter Anvin 
Cc: Miguel Boton 
Cc: Russ Anderson 
Cc: Robin Holt 
Cc: Russell King 
Cc: Guan Xuetao 
Acked-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

reboot: checkpatch.pl the new kernel/reboot.c file

2013-07-09T17:33:29+00:00

Get the new file to pass scripts/checkpatch.pl

Signed-off-by: Robin Holt 
Cc: H. Peter Anvin 
Cc: Russ Anderson 
Cc: Robin Holt 
Cc: Russell King 
Cc: Guan Xuetao 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

UAPI: (Scripted) Disintegrate include/linux

2012-10-13T09:46:48+00:00

Signed-off-by: David Howells 
Acked-by: Arnd Bergmann 
Acked-by: Thomas Gleixner 
Acked-by: Michael Kerrisk 
Acked-by: Paul E. McKenney 
Acked-by: Dave Jones