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* powerpc: Re-enable preemption before cpu_die()Signed-off-by: Darren Hart2010-08-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | start_secondary() is called shortly after _start and also via cpu_idle()->cpu_die()->pseries_mach_cpu_die() start_secondary() expects a preempt_count() of 0. pseries_mach_cpu_die() is called via the cpu_idle() routine with preemption disabled, resulting in the following repeating message during rapid cpu offline/online tests with CONFIG_PREEMPT=y: BUG: scheduling while atomic: swapper/0/0x00000002 Modules linked in: autofs4 binfmt_misc dm_mirror dm_region_hash dm_log [last unloaded: scsi_wait_scan] Call Trace: [c00000010e7079c0] [c0000000000133ec] .show_stack+0xd8/0x218 (unreliable) [c00000010e707aa0] [c0000000006a47f0] .dump_stack+0x28/0x3c [c00000010e707b20] [c00000000006e7a4] .__schedule_bug+0x7c/0x9c [c00000010e707bb0] [c000000000699d9c] .schedule+0x104/0x800 [c00000010e707cd0] [c000000000015b24] .cpu_idle+0x1c4/0x1d8 [c00000010e707d70] [c0000000006aa1b4] .start_secondary+0x398/0x3d4 [c00000010e707e30] [c000000000008278] .start_secondary_resume+0x10/0x14 Move the cpu_die() call inside the existing preemption enabled block of cpu_idle(). This is safe as the idle task is affined to a single CPU so the debug_smp_processor_id() tests (from cpu_should_die()) won't trigger as we are in a "migration disabled" region. Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Acked-by: Will Schmidt <will_schmidt@vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Nathan Fontenot <nfont@austin.ibm.com> Cc: Robert Jennings <rcj@linux.vnet.ibm.com> Cc: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* sysctl: Drop & in front of every proc_handler.Eric W. Biederman2009-11-181-1/+1
| | | | | | | | | | | For consistency drop & in front of every proc_handler. Explicity taking the address is unnecessary and it prevents optimizations like stubbing the proc_handlers to NULL. Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Joe Perches <joe@perches.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* sysctl powerpc: Remove dead binary sysctl supportEric W. Biederman2009-11-121-2/+0
| | | | | | | | | Now that sys_sysctl is a generic wrapper around /proc/sys .ctl_name and .strategy members of sysctl tables are dead code. Remove them. Cc: Paul Mackerras <paulus@samba.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* powerpc: ftrace, do not latency trace idleSteven Rostedt2008-11-201-0/+5
| | | | | | | | | | | | Impact: fix for irq off latency tracer When idle is called, interrupts are disabled, but the idle function will still wake up on an interrupt. The problem is that the interrupt disabled latency tracer will take this call to idle as a latency. This patch disables the latency tracing when going into idle. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* powerpc: Fix failure to shutdown with CPU hotplugJohannes Berg2008-09-301-5/+1
| | | | | | | | | | | | | | | | | | | I tracked down the shutdown regression to CPUs not dying when being shut down during power-off. This turns out to be due to the system_state being SYSTEM_POWER_OFF, which this code doesn't take as a valid state for shutting off CPUs in. This has never made sense to me, but when I added hotplug code to implement hibernate I only "made it work" and did not question the need to check the system_state. Thomas Gleixner helped me dig, but the only thing we found is that it was added with the original commit that added CPU hotplug support. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Joel Schopp <jschopp@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* nohz: prevent tick stop outside of the idle loopThomas Gleixner2008-07-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <jack.ren@marvell.com>, Debugged-by: eric miao <eric.y.miao@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* [POWERPC] Fix sysctl table check failure on PowerMacAlexey Dobriyan2007-11-081-1/+1
| | | | | | | kernel was marked with 0755. Everywhere else it's 0555. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [POWERPC] Enable tickless idle and high res timers for powerpcTony Breeds2007-10-031-0/+3
| | | | | Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [POWERPC] powermac: Suspend to disk on G5Johannes Berg2007-05-071-1/+4
| | | | | | | | | | | | | | Powermac G5 suspend to disk implementation. The code is platform agnostic but only tested on powermac, no other 64-bit powerpc machines. Because nvidiafb still breaks suspend I have marked it EXPERIMENTAL on powermac and because I can't test it and some lowlevel code will need changes it is BROKEN on all other 64-bit platforms. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] sysctl: remove insert_at_head from register_sysctlEric W. Biederman2007-02-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The semantic effect of insert_at_head is that it would allow new registered sysctl entries to override existing sysctl entries of the same name. Which is pain for caching and the proc interface never implemented. I have done an audit and discovered that none of the current users of register_sysctl care as (excpet for directories) they do not register duplicate sysctl entries. So this patch simply removes the support for overriding existing entries in the sys_sysctl interface since no one uses it or cares and it makes future enhancments harder. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andi Kleen <ak@muc.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Corey Minyard <minyard@acm.org> Cc: Neil Brown <neilb@suse.de> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Jan Kara <jack@ucw.cz> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: David Chinner <dgc@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] sysctl: C99 convert ctl_tables in arch/powerpc/kernel/idle.cEric W. Biederman2007-02-141-3/+8
| | | | | | | | | | This was partially done already and there was no ABI breakage what a relief. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [POWERPC] cell: use ppc_md->power_save instead of cbe_idle_looparnd@arndb.de2006-10-251-0/+7
| | | | | | | | | | | | This moves the cell idle function to use the default cpu_idle with a special power_save callback, like all other platforms except iSeries already do. It also makes it possible to disable this power_save function with a new powerpc-specific boot option "powersave=off". Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-301-1/+0
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] powerpc: Ensure runlatch is off in the idle loopAnton Blanchard2006-04-131-2/+2
| | | | | | | | | Since external and decrementer interrupts set the runlatch on, we need to ensure its set off again in the idle loop. At the moment we dont turn it off in the inner loop. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc: Unify the 32 and 64 bit idle loopsPaul Mackerras2006-03-271-0/+122
This unifies the 32-bit (ARCH=ppc and ARCH=powerpc) and 64-bit idle loops. It brings over the concept of having a ppc_md.power_save function from 32-bit to ARCH=powerpc, which lets us get rid of native_idle(). With this we will also be able to simplify the idle handling for pSeries and cell. Signed-off-by: Paul Mackerras <paulus@samba.org>
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