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path: root/arch/s390/lib/delay.c
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2009-10-06[S390] Provide arch specific mdelay implementation.Heiko Carstens
Use an own implementation instead of the common code udelay loop. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06[S390] Fix enabled udelay for short delays.Christian Borntraeger
When udelay() gets called with a delay that would expire before the next clock event it reprograms the clock comparator. When the interrupt happens the clock comparator won't be resetted therefore the interrupt condition doesn't get cleared. The result is an endless timer interrupt loop until the next clock event would expire (stored in lowcore). So udelay() usually would wait much longer for small delays than it should. Fix this by disabling the local tick which makes sure that the clock comparator will be resetted when a timer interrupt happens. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-07-07[S390] udelay: disable lockdep to avoid false positivesHeiko Carstens
Our udelay implementation enables interrupts to receive a special timer interrupt regardless of the context it is called from. This might lead to false positive lockdep reports. Since lockdep isn't aware of the fact that only a single interrupt source is enabled it warns about possible deadlocks that in reality won't happen, like the one below. To fix this disable lockdep before enabling interrupts. [ 254.040888] ================================= [ 254.040904] [ INFO: inconsistent lock state ] [ 254.040910] 2.6.30 #9 [ 254.040914] --------------------------------- [ 254.040920] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. [ 254.040927] swapper/0 [HC0[0]:SC1[1]:HE1:SE0] takes: [ 254.040934] (sch->lock){?.-...}, at: [<00000000002e4778>] ccw_device_timeout+0x48/0x2f0 [ 254.040961] {IN-HARDIRQ-W} state was registered at: [ 254.040969] [<0000000000096f74>] __lock_acquire+0x9d4/0x188c [ 254.040985] [<0000000000097f68>] lock_acquire+0x13c/0x16c [ 254.040998] [<00000000004527e0>] _spin_lock+0x74/0xb8 [ 254.041016] [<0000000000457eb2>] do_IRQ+0xde/0x208 [ 254.041031] [<000000000002d190>] io_return+0x0/0x8 [ 254.041049] [<0000000000029faa>] vtime_stop_cpu+0xbe/0x114 [ 254.041066] irq event stamp: 259629 [ 254.041076] hardirqs last enabled at (259628): [<000000000045238e>] _spin_unlock_irq+0x5e/0x9c [ 254.041095] hardirqs last disabled at (259629): [<000000000045292e>] _spin_lock_irq+0x4a/0xc4 [ 254.041126] softirqs last enabled at (259614): [<000000000006500e>] __do_softirq+0x296/0x2b0 [ 254.041137] softirqs last disabled at (259619): [<0000000000024cf6>] do_softirq+0x102/0x108 [ 254.041147] [ 254.041148] other info that might help us debug this: [ 254.041153] 2 locks held by swapper/0: [ 254.041157] #0: (&priv->timer){+.-...}, at: [<000000000006bf9a>] run_timer_softirq+0x19a/0x340 [ 254.041170] #1: (sch->lock){?.-...}, at: [<00000000002e4778>] ccw_device_timeout+0x48/0x2f0 [ 254.041182] [ 254.041310] Call Trace: [ 254.041313] ([<00000000000174fc>] show_trace+0x16c/0x170) [ 254.041321] [<0000000000017578>] show_stack+0x78/0x104 [ 254.041327] [<000000000044d0ca>] dump_stack+0xc6/0xd4 [ 254.041342] [<00000000000949b4>] print_usage_bug+0x1c8/0x1fc [ 254.041353] [<0000000000094e8a>] mark_lock+0x4a2/0x670 [ 254.041364] [<00000000000950e2>] mark_held_locks+0x8a/0xb4 [ 254.041375] [<0000000000095398>] trace_hardirqs_on_caller+0x74/0x1ac [ 254.041388] [<00000000000954fa>] trace_hardirqs_on+0x2a/0x38 [ 254.041402] [<000000000025f1ec>] __udelay_disabled+0xac/0xfc [ 254.041419] [<000000000025f432>] __udelay+0x12a/0x148 [ 254.041433] [<00000000002d64d8>] cio_commit_config+0x170/0x290 [ 254.041451] [<00000000002d6978>] cio_disable_subchannel+0x120/0x1cc [ 254.041468] [<00000000002e32a4>] ccw_device_recog_done+0x54/0x2f4 [ 254.041485] [<00000000002e3638>] ccw_device_sense_id_done+0x50/0x90 [ 254.041508] [<00000000002e615a>] snsid_callback+0xfa/0x3a8 [ 254.041515] [<00000000002dd96c>] ccwreq_stop+0x80/0x90 [ 254.041523] [<00000000002dda8e>] ccw_request_timeout+0xc2/0xd0 [ 254.041530] [<00000000002e2f70>] ccw_device_request_event+0x58/0x90 [ 254.041537] [<00000000002e47ae>] ccw_device_timeout+0x7e/0x2f0 [ 254.041555] [<000000000006c02a>] run_timer_softirq+0x22a/0x340 [ 254.041566] [<0000000000064eb0>] __do_softirq+0x138/0x2b0 [ 254.041578] [<0000000000024cf6>] do_softirq+0x102/0x108 [ 254.041590] [<00000000000647ce>] irq_exit+0xee/0x114 [ 254.041603] [<0000000000457d88>] do_extint+0x130/0x17c [ 254.041617] [<000000000002d41e>] ext_no_vtime+0x1e/0x22 [ 254.041631] [<0000000000029faa>] vtime_stop_cpu+0xbe/0x114 [ 254.041646] ([<0000000000029f58>] vtime_stop_cpu+0x6c/0x114) [ 254.041662] [<000000000001d842>] cpu_idle+0x122/0x1c0 [ 254.041679] [<00000000004482c6>] start_secondary+0xce/0xe0 [ 254.041696] [<0000000000000000>] 0x0 [ 254.041715] [<0000000000000000>] 0x0 [ 254.041745] INFO: lockdep is turned off. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26[S390] move EXPORT_SYMBOLs to definitionsHeiko Carstens
Move all EXPORT_SYMBOLs to their corresponding definitions. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-10[S390] Move private simple udelay function to arch/s390/lib/delay.c.Heiko Carstens
Move cio's private simple udelay function to lib/delay.c and turn it into something much more readable. So we have all implementations at one place. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-03[S390] nohz: Fix __udelay.Heiko Carstens
This fixes a regression that came with 934b2857cc576ae53c92a66e63fce7ddcfa74691 ("[S390] nohz/sclp: disable timer on synchronous waits."). If udelay() gets called from a disabled context it sets the clock comparator to a value where it expects the next interrupt. When the interrupt happens the clock comparator gets not reset and therefore the interrupt condition doesn't get cleared. The result is an endless timer interrupt loop. In addition this patch fixes also the following: rcutorture reveals that our __udelay implementation is still buggy, since it might schedule tasklets, but prevents their execution: NOHZ: local_softirq_pending 42 NOHZ: local_softirq_pending 02 NOHZ: local_softirq_pending 142 NOHZ: local_softirq_pending 02 To fix this we make sure that only the clock comparator interrupt is enabled when the enabled wait psw is loaded. Also no code gets called anymore which might schedule tasklets. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-08-01[S390] nohz/sclp: disable timer on synchronous waits.Heiko Carstens
sclp_sync_wait wait synchronously for an sclp interrupt and disables timer interrupts. However on the irq enter paths there is an extra check if a timer interrupt would be due and calls the timer callback. This would schedule softirqs in the wrong context. So introduce local_tick_enable/disable which prevents this. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-04-17[S390] Convert s390 to GENERIC_CLOCKEVENTS.Heiko Carstens
This way we get rid of s390's NO_IDLE_HZ and use the generic dynticks variant instead. In addition we get high resolution timers for free. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-02-21[S390] prevent softirqs if delay is called disabledMartin Schwidefsky
The new delay implementation uses the clock comparator and an external interrupt even if it is called disabled for interrupts. To do this all external interrupt source except clock comparator are switched of before enabling external interrupts. The external interrupt at the end of the delay period may not execute softirqs or we can end up in a dead-lock. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05[S390] ETR support.Martin Schwidefsky
This patch adds support for clock synchronization to an external time reference (ETR). The external time reference sends an oscillator signal and a synchronization signal every 2^20 microseconds to keep the TOD clocks of all connected servers in sync. For availability two ETR units can be connected to a machine. If the clock deviates for more than the sync-check tolerance all cpus get a machine check that indicates that the clock is out of sync. For the lovely details how to get the clock back in sync see the code below. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-28[S390] Inline assembly cleanup.Martin Schwidefsky
Major cleanup of all s390 inline assemblies. They now have a common coding style. Quite a few have been shortened, mainly by using register asm variables. Use of the EX_TABLE macro helps as well. The atomic ops, bit ops and locking inlines new use the Q-constraint if a newer gcc is used. That results in slightly better code. Thanks to Christian Borntraeger for proof reading the changes. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-06-30Remove obsolete #include <linux/config.h>Jörn Engel
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-02-14[PATCH] s390: fix __delay implementationHeiko Carstens
Fix __delay implementation. Called with an argument "1" or "0" it would loop nearly forever (since (1/2)-1 = 0xffffffff). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!