kernel.git/arch/avr32/kernel/process.c, branch linux-2.6.28.y

avr32: Minor pm_power_off cleanup

2008-10-08T16:44:58Z

Include to see the declaration of pm_power_off, and remove unneeded NULL initializer. Signed-off-by: Haavard Skinnemoen

avr32: Use instead of

2008-08-05T12:36:57Z

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

2008-07-18T16:10:28Z

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

2008-04-20T00:40:11Z

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

2008-04-20T00:40:07Z

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

2008-02-27T13:23:53Z

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

2008-02-15T13:55:10Z

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

[AVR32] Enable debugging only when needed

2008-01-25T07:31:39Z

Keep track of processes being debugged (including the kernel itself) and turn the OCD system on and off as appropriate. Since enabling debugging turns off some optimizations in the CPU core, this fixes the issue that enabling KProbes support or simply running a program under gdbserver will reduce system performance significantly until the next reboot. The CPU performance will still be reduced for all processes while a process is being debugged, but this is a lot better than reducing the performance forever. Signed-off-by: Haavard Skinnemoen

[AVR32] Clean up OCD register usage

2007-12-07T13:54:40Z

Generate a new set of OCD register definitions in asm/ocd.h and rename __mfdr() and __mtdr() to ocd_read() and ocd_write() respectively. The bitfield definitions are a lot more complete now, and they are entirely based on bit numbers, not masks. This is because OCD registers are frequently accessed from assembly code, where bit numbers are a lot more useful (can be fed directly to sbr, bfins, etc.) Bitfields that consist of more than one bit have two definitions: _START, which indicates the number of the first bit, and _SIZE, which indicates the number of bits. These directly correspond to the parameters taken by the bfextu, bfexts and bfins instructions. Signed-off-by: Haavard Skinnemoen

[AVR32] Fix invalid status register bit definitions in asm/ptrace.h

2007-12-07T13:52:33Z

The 'H' bit is bit 29, while the 'R' bit doesn't exist. Luckily, we don't actually use any of the bits in question. Also update show_regs() to show the Debug Mask and Debug state bits. Signed-off-by: Haavard Skinnemoen