linux-toradex.git/arch/avr32/kernel/process.c, branch v2.6.32.31

ptrace: remove PT_DTRACE from avr32, mn10300, parisc, s390, sh, xtensa

2009-06-18T20:03:48+00:00

avr32, mn10300, parisc, s390, sh, xtensa:

They never set PT_DTRACE, but clear it after do_execve().

Signed-off-by: Oleg Nesterov 
Cc: David Howells 
Acked-by: Kyle McMartin 
Cc: Grant Grundler 
Cc: Matthew Wilcox 
Acked-by: Martin Schwidefsky 
Cc: Heiko Carstens 
Acked-by: Paul Mundt 
Acked-by: Chris Zankel 
Acked-by: Roland McGrath 
Acked-by: Haavard Skinnemoen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Simplify copy_thread()

2009-04-03T02:04:51+00:00

First argument unused since 2.3.11.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

avr32: Introducing asm/syscalls.h

2008-12-17T12:32:38+00:00

Declaring arch-dependent syscalls for avr32 architecture

Signed-off-by: Jaswinder Singh 
Signed-off-by: Haavard Skinnemoen

avr32: Minor pm_power_off cleanup

2008-10-08T16:44:58+00:00

Include  to see the declaration of pm_power_off, and remove
unneeded NULL initializer.

Signed-off-by: Haavard Skinnemoen

avr32: Use instead of

2008-08-05T12:36:57+00:00

Update all avr32-specific files to use the new platform-specific header
locations. Drivers shared with ARM are left alone for now.

Signed-off-by: Haavard Skinnemoen

nohz: prevent tick stop outside of the idle loop

2008-07-18T16:10:28+00:00

Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:

	scheduler switch to idle task
	enable interrupts

Window starts here

	----> interrupt happens (does not set NEED_RESCHED)
	      	irq_exit() stops the tick

	----> interrupt happens (does set NEED_RESCHED)

	return from schedule()
	
	cpu_idle(): preempt_disable();

Window ends here

The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.

The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.

Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.

cpu_idle()
{
	preempt_disable();

	while(1) {
		 tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we
		 			          are in the idle loop

		 while (!need_resched())
		       halt();

		 tick_nohz_restart_sched_tick(); <- disables NOHZ mode
		 preempt_enable_no_resched();
		 schedule();
		 preempt_disable();
	}
}

In hindsight we should have done this forever, but ... 

/me grabs a large brown paperbag.

Debugged-by: Jack Ren , 
Debugged-by: eric miao 
Signed-off-by: Thomas Gleixner

avr32: Add hardware power-down function call

2008-04-20T00:40:11+00:00

This patch adds in the indirect call to pm_power_off(), as is done in
other architectures (e.g. ARM).

Tested on NGW100, with custom board with GPIO control over main DC
power.

Signed-off-by: Peter Ma 
Signed-off-by: Haavard Skinnemoen

avr32: Move sleep code into mach-at32ap

2008-04-20T00:40:07+00:00

Create a new file, pm-at32ap700x.S, in mach-at32ap and move the CPU
idle sleep code there. Make it possible to disable the sleep code.

Signed-off-by: Haavard Skinnemoen

avr32: Fix OCD refcounting bug

2008-02-27T13:23:53+00:00

Iff the parent has TIF_DEBUG set, _and_ clone_flags includes
CLONE_PTRACE we should set the TIF_DEBUG flag for the child and
increment the ocd refcount. Otherwise, the TIF_DEBUG flag must be
unset.

Currently, the child inherits TIF_DEBUG from the parent before
copy_thread is called, so TIF_DEBUG may be already be set before we
determine whether the child is supposed to inherit debugging
capabilities from the parent or not. This means that ocd_enable()
won't increment the refcount, because TIF_DEBUG is already set, and
that TIF_DEBUG will be set for processes that aren't being debugged.

This leads to a refcounting asymmetry, which may show up as

------------[ cut here ]------------
Badness at arch/avr32/kernel/ocd.c:73
PC is at ocd_disable+0x34/0x60
LR is at put_lock_stats+0xa/0x20

as reported by David Brownell. Happens when strace'ing a process that
forks a new child process, e.g. "strace mount -tjffs2 mtd1 /mnt", and
subsequently killing the child process (e.g. "umount /mnt".)

Signed-off-by: Haavard Skinnemoen

avr32: Call tick_nohz_{stop,restart}_sched_tick() in idle loop

2008-02-15T13:55:10+00:00

This fixes a hang on boot with nohz enabled. nohz is not actually
supported in mainline yet, but patches that add support for it are
currently under review.

When nohz is compiled out, the functions are no-ops, so this patch
results in no functional change, but it arguably makes the code more
correct.

Signed-off-by: Haavard Skinnemoen