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path: root/drivers/char/hvc_console.c
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* hvc_console: Provide (un)locked version for hvc_resize()Hendrik Brueckner2009-09-24
| | | | | | | | | | | | | | | | | | Rename the locking free hvc_resize() function to __hvc_resize() and provide an inline function that locks the hvc_struct and calls __hvc_resize(). The rationale for this patch is that virtio_console calls the hvc_resize() function without locking the hvc_struct. So it needs to call the lock itself. According to naming rules, the unlocked version is renamed and prefixed with "__". References to unlocked function calls in hvc back-ends has been updated. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Drop unnecessary NULL testJulia Lawall2009-08-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The result of container_of should not be NULL. In particular, in this case the argument to the enclosing function has passed though INIT_WORK, which dereferences it, implying that its container cannot be NULL. A simplified version of the semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ identifier fn,work,x,fld; type T; expression E1,E2; statement S; @@ static fn(struct work_struct *work) { ... when != work = E1 x = container_of(work,T,fld) ... when != x = E2 - if (x == NULL) S ... } // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* tty: fix chars_in_buffersAlan Cox2009-07-20
| | | | | | | | | | | This function does not have an error return and returning an error is instead interpreted as having a lot of pending bytes. Reported by Jeff Harris who provided a list of some of the remaining offenders. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hvc_console: Remove tty->low_latencyHendrik Brueckner2009-01-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes the tty->low_latency setting. For irq based hvc_console backends the tty->low_latency must be set to 0, because the tty_flip_buffer_push() function must not be called from IRQ context (see drivers/char/tty_buffer.c). For polled backends, the low_latency setting causes the bug trace below, because tty_flip_buffer_push() is called within an atomic context and subsequent calls might sleep due to mutex_lock. BUG: sleeping function called from invalid context at /root/cvs/linux-2.6.git/kernel/mutex.c:207 in_atomic(): 1, irqs_disabled(): 0, pid: 748, name: khvcd 1 lock held by khvcd/748: #0: (hvc_structs_lock){--..}, at: [<00000000002ceb50>] khvcd+0x58/0x12c CPU: 0 Not tainted 2.6.29-rc1git #29 Process khvcd (pid: 748, task: 000000002fb9a480, ksp: 000000002f66bd78) 070000000000000a 000000002f66ba00 0000000000000002 (null) 000000002f66baa0 000000002f66ba18 000000002f66ba18 0000000000104f08 ffffffffffffc000 000000002f66bd78 (null) (null) 000000002f66ba00 000000000000000c 000000002f66ba00 000000002f66ba70 0000000000466af8 0000000000104f08 000000002f66ba00 000000002f66ba50 Call Trace: ([<0000000000104e7c>] show_trace+0x138/0x158) [<0000000000104f62>] show_stack+0xc6/0xf8 [<0000000000105740>] dump_stack+0xb0/0xc0 [<000000000013144a>] __might_sleep+0x14e/0x17c [<000000000045e226>] mutex_lock_nested+0x42/0x3b4 [<00000000002c443e>] echo_char_raw+0x3a/0x9c [<00000000002c688c>] n_tty_receive_buf+0x1154/0x1208 [<00000000002ca0a2>] flush_to_ldisc+0x152/0x220 [<00000000002ca1da>] tty_flip_buffer_push+0x6a/0x90 [<00000000002cea74>] hvc_poll+0x244/0x2c8 [<00000000002ceb68>] khvcd+0x70/0x12c [<000000000015bbd0>] kthread+0x68/0xa0 [<0000000000109d5a>] kernel_thread_starter+0x6/0xc [<0000000000109d54>] kernel_thread_starter+0x0/0xc 1 lock held by khvcd/748: #0: (hvc_structs_lock){--..}, at: [<00000000002ceb50>] khvcd+0x58/0x12c Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Use kzalloc() instead of kmalloc() + memset()Milton Miller2009-01-12
| | | | | | | Replace kmalloc() + memset() with kzalloc(). Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Do not set low_latency when using interruptsMilton Miller2009-01-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | hvc_console is setting low_latency unconditionally, but some clients are interrupt driven and will call hvc_poll from irq context. This will cause tty_flip_buffer_push to be called from irq context, and it very clearly states it must not be called from IRQ when low_latency is specified. Looking back through history: v2.6.16-rc1 via 33f0f88f1c51ae5c2d593d26960c760ea154c2e2 [PATCH] TTY layer buffering revamp added this new api. v2.6.16-rc3 via 8977d929e49021d9a6e031310aab01fa72f849c2 [PATCH] tty buffering stall fix claims to fix a stall discovered with hvc_console v2.6.16-rc5 via fb5c594c2acc441f0d2d8f457484a0e0e9285db3 [PATCH] Fix race condition in hvc console. said set this flag to avoid a stall problem, and was merged through the powerpc arch tree. Without searching for email discussions, it would appear to be an overlapping "fix", but one that did not consider all users. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Change an mb() to smp_mb() and add some commentsMilton Miller2009-01-12
| | | | | | | | | | I remember some history on this barrier. There was a race between open via /dev/console and the tty being fully setup. Its also why there is a temporary variable and the global is assigned at the end of the function. Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* pty: simplify resizeAlan Cox2009-01-02
| | | | | | | | We have special case logic for resizing pty/tty pairs. We also have a per driver resize method so for the pty case we should use it. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio_console: support console resizingChristian Borntraeger2008-12-29
| | | | | | | | | | | | | | this patch uses the new hvc callback hvc_resize to set the window size which allows to change the tty size of hvc_console via a hvc_resize function. I have added a new feature bit VIRTIO_CONSOLE_F_SIZE. The driver will change the window size on tty open and via the config_changed callback of the transport. Currently lguest and kvm_s390 have not implemented this callback, but the callback can be implemented at a later point in time. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* hvc_console: Escape magic sysrq keyHendrik Brueckner2008-12-20
| | | | | | | | | | | | | | | | The ctrl-o (^O) is a common control key used by several applications, such as vim, but hvc_console uses ^O as the magic-sysrq key. This commit allows users to send ^O to applications by pressing ^O twice in succession. To implement this, this commit introduces a check if ^O is pressed again if the sysrq_pressed variable is already set. In this case, clear sysrq_pressed state and flip the ^O character to the tty. (The old behavior has always set "sysrq_pressed" if ^O has been entered, and it has not flipped the ^O character to the tty.) Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* hvc_console: Always schedule resize work on resizeHendrik Brueckner2008-12-03
| | | | | | | | | | | | The test to check for a new winsize runs out-of-sync with the underlying tty. After a tty has been released and initialized again, the winsize might differ between the tty and the hp struct. The solution is to simply remove the check and always schedule the resize work. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* hvc_console: Remove __devexit annotation of hvc_remove()Hendrik Brueckner2008-10-21
| | | | | | | | | | Removed __devexit annotation of hvc_remove() to avoid a section mismatch if the backend initialization fails and hvc_remove() must be used to clean up allocated hvc structs (called in section __init or __devinit). Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Add support for tty window resizingHendrik Brueckner2008-10-21
| | | | | | | | | | | | | | | | | The patch provides the hvc_resize() function to update the terminal window dimensions (struct winsize) for a specified hvc console. The function stores the new window size and schedules a function that finally updates the tty winsize and signals the change to user space (SIGWINCH). Because the winsize update must acquire a mutex and might sleep, the function is scheduled instead of being called from hvc_poll() or khvcd. This patch uses the tty_do_resize() routine from the tty layer. A pending resize work is canceled in hvc_close() and hvc_hangup(). Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Fix loop if put_char() returns 0Hendrik Brueckner2008-10-21
| | | | | | | | | | | | | | | | | | | | | | | | | If put_char() routine of a hvc console backend returns 0, then the hvc console starts looping in the following scenarios: 1. hvc_console_print() If put_char() returns 0 then the while loop may loop forever. I have added the missing check for 0 to throw away console messages. 2. khvcd may loop: The thread calls hvc_poll() --> hvc_push()... if there are still buffered data then the HVC_POLL_WRITE bit is set and causes the khvcd thread to loop (if yield() returns immediately). However, instead of looping, the khvcd thread could sleep for MIN_TIMEOUT (doing the same as for get_chars()). The MIN_TIMEOUT is set if hvc_push() was not able to write data to the backend. If data has been written, the timeout is set to 0 to immediately re-schedule hvc_poll(). Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> (virtio_console) Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Add tty driver flag TTY_DRIVER_RESET_TERMIOSHendrik Brueckner2008-10-21
| | | | | | | | | | | | | | | After a tty hangup() or close() operation, processes might not reset the termio settings to a sane state. In order to reset the termios to its default settings the tty driver flag TTY_DRIVER_RESET_TERMIOS has been added. TTY driver flag description from include/linux/tty_driver.h: TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the termios setting when the last process has closed the device. Used for PTY's, in particular. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* hvc_console: Add a hangup notifier for backendsHendrik Brueckner2008-10-21
| | | | | | | | | | I have added a hangup notifier that can be used by hvc console backends to handle a tty hangup. The default irq hangup notifier calls the notifier_del_irq() for compatibility. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* Merge commit 'origin'Benjamin Herrenschmidt2008-10-14
|\ | | | | | | | | | | Manual fixup of conflicts on: arch/powerpc/include/asm/dcr-regs.h drivers/net/ibm_newemac/core.h
| * drivers/char/hvc_console.c: adjust call to put_tty_driverJulia Lawall2008-10-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The call to put_tty_driver is out of place and is applied to the wrong argument. The function enclosing the patched code calls alloc_tty_driver and stores the result in drv. Subsequently, there are two occurrences of error handling code, one making a goto to put_tty and one making a goto to stop_thread. At the point of the first one the assignment hvc_driver = drv has not yet been executed, and from inspecting the rest of the file it seems that hvc_driver would be NULL. Thus the current call to put_tty_driver is useless, and one applied to drv is needed. The goto stop_thread is in the error handling code for a call to tty_register_driver, but the error cases in tty_register_driver do not free its argument, so it should be done here. Thus, I have moved the put_tty label after the stop_thread label, so that put_tty_driver is called in both cases. The semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @r exists@ local idexpression x; expression E,f; position p1,p2,p3; identifier l; statement S; @@ x = alloc_tty_driver@p1(...) ... if (x == NULL) S ... when != E = x when != put_tty_driver(x) goto@p2 l; ... when != E = x when != f(...,x,...) when any ( return \(0\|x\); | return@p3 ...; ) @script:python@ p1 << r.p1; p2 << r.p2; p3 << r.p3; @@ print "%s: call on line %s not freed or saved before return on line %s via line %s" % (p1[0].file,p1[0].line,p3[0].line,p2[0].line) // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | hvc_console: Fix free_irq in spinlocked sectionChristian Borntraeger2008-10-14
|/ | | | | | | | | | | | | commit 611e097d7707741a336a0677d9d69bec40f29f3d Author: Christian Borntraeger <borntraeger@de.ibm.com> hvc_console: rework setup to replace irq functions with callbacks introduced a spinlock recursion problem. The notifier_del is called with a lock held, and in turns calls free_irq which then complains when manipulating procfs. This fixes it by moving the call to the notifier to outside of the locked section. Signed-off-by: Christian Borntraeger<borntraeger@de.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* fix spinlock recursion in hvc_consoleChristian Borntraeger2008-08-12
| | | | | | | | | | | | | | | | | | commit 611e097d7707741a336a0677d9d69bec40f29f3d Author: Christian Borntraeger <borntraeger@de.ibm.com> hvc_console: rework setup to replace irq functions with callbacks introduced a spinlock recursion problem. request_irq tries to call the handler if the IRQ is shared. The irq handler of hvc_console calls hvc_poll and hvc_kill which might take the hvc_struct spinlock. Therefore, we have to call request_irq outside the spinlock. We can move the notifier_add safely outside the spinlock as ->data must not be changed by the backend. Otherwise, tty_hangup would fail anyway. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: console as a config optionChristian Borntraeger2008-07-24
| | | | | | | | | | | I also added a small Kconfig change that allows the user to specify the virtio console in menuconfig. (Fixes to export symbols from Stephen Rothwell <sfr@canb.auug.org.au>) (Fixes for CONFIG_VIRTIO_CONSOLE=y vs CONFIG_VIRTIO=m from Christian himself) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
* hvc_console: rework setup to replace irq functions with callbacksChristian Borntraeger2008-07-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch tries to change hvc_console to not use request_irq/free_irq if the backend does not use irqs. This allows virtio_console to use hvc_console without having a linker reference to request_irq/free_irq. In addition, together with patch 2/3 it improves the performance for virtio console input. (an earlier version of this patch was tested by Yajin on lguest) The irq specific code is moved to hvc_irq.c and selected by the drivers that use irqs (System p, System i, XEN). I replaced "int irq" with the opaque "int data". The request_irq and free_irq calls are replaced with notifier_add and notifier_del. I have also changed the code a bit to call the notifier_add and notifier_del inside the spinlock area as the callbacks are found via hp->ops. Changes since last version: o remove ifdef o reintroduce "irq_requested" as "notified" o cleanups, sparse.. I did not move the timer based polling into a separate polling scheme. I played with several variants, but it seems we need to sleep/schedule in a thread even for irq based consoles, as there are throttleing and buffer size constraints. I also kept hvc_struct defined in hvc_console.h so that hvc_irq.c can access the irq_requested element. Feedback is appreciated. virtio_console is currently the only available console for kvm on s390. I plan to push this change as soon as all affected parties agree on it. I would love to get test results from System p, Xen etc. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* [POWERPC] Make cpus_in_xmon static and remove extern mess from hvc_console.cMichael Ellerman2008-05-14
| | | | | | | | | This is a little messier than I'd like because xmon.h only exists on powerpc and we can't have a static inline and an extern declaration visible at the same time. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
* drivers/char: use LIST_HEAD instead of LIST_HEAD_INITDenis Cheng2008-02-06
| | | | | | | | | | | | | single list_head variable initialized with LIST_HEAD_INIT could almost always can be replaced with LIST_HEAD declaration, this shrinks the code and looks better. Signed-off-by: Denis Cheng <crquan@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Corey Minyard <minyard@acm.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kobject: convert hvc_console to use kref, not kobjectGreg Kroah-Hartman2008-01-24
| | | | | | | | | | | | | | hvc_console is using a kobject only for reference counting, nothing else. So switch it to use a kref instead, which is all that is needed, and is much smaller. Cc: Anton Blanchard <anton@au.ibm.com> Cc: Paul Mackerras <paulus@au.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ryan S. Arnold <rsa@us.ibm.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Delay creation of khcvd threadRusty Russell2007-10-17
| | | | | | | | | | | | | | | | This changes hvc_init() to be called only when someone actually uses the hvc_console driver. Dave Jones complained when profiling bootup. hvc_console used to only be for Power aka pSeries: now lguest and Xen both want it built-in in case the kernel is a guest under one of those, even though usually it will be a native boot. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Freezer: make kernel threads nonfreezable by defaultRafael J. Wysocki2007-07-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the freezer treats all tasks as freezable, except for the kernel threads that explicitly set the PF_NOFREEZE flag for themselves. This approach is problematic, since it requires every kernel thread to either set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't care for the freezing of tasks at all. It seems better to only require the kernel threads that want to or need to be frozen to use some freezer-related code and to remove any freezer-related code from the other (nonfreezable) kernel threads, which is done in this patch. The patch causes all kernel threads to be nonfreezable by default (ie. to have PF_NOFREEZE set by default) and introduces the set_freezable() function that should be called by the freezable kernel threads in order to unset PF_NOFREEZE. It also makes all of the currently freezable kernel threads call set_freezable(), so it shouldn't cause any (intentional) change of behaviour to appear. Additionally, it updates documentation to describe the freezing of tasks more accurately. [akpm@linux-foundation.org: build fixes] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [POWERPC] Make drivers/char/hvc_console.c:khvcd() staticAdrian Bunk2007-07-10
| | | | | | Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* drivers/char/hvc_console.c: cleanupsAdrian Bunk2007-05-08
| | | | | | | | | | - make needlessly global code static - remove the unused EXPORT_SYMBOL's Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [POWERPC] hvc_console: Typo fixeswill schmidt2007-04-24
| | | | | | | Fix a handful of comment typos for hvc_console. Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [POWERPC] hvc_console: Polling mode timer backoffWill Schmidt2007-04-24
| | | | | | | | | | | | | | | | | | Add a back-off mechanism to hvc_console's polling logic. This change drops the timers/second ratio from ~90 to ~1/2 while the console is idle. This change is most noticeable when watching /proc/timer_stats output. This only affects when the hvc_console is running in poll mode, i.e. power4 and cell systems. I've tested on Power4, Michael Ellerman has both contributed to the patch and tested on cell. Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] Make hvc_console.c compile on non-powerpc: Remove NO_IRQRusty Russell2007-02-26
| | | | | | | | | Paulus preferred this over #defining NO_IRQ in the file, since that's 0 for powerpc anyway. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Add include/linux/freezer.h and move definitions from sched.hNigel Cunningham2006-12-07
| | | | | | | | | | | | | Move process freezing functions from include/linux/sched.h to freezer.h, so that modifications to the freezer or the kernel configuration don't require recompiling just about everything. [akpm@osdl.org: fix ueagle driver] Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* IRQ: Maintain regs pointer globally rather than passing to IRQ handlersDavid Howells2006-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
* [PATCH] const struct tty_operationsJeff Dike2006-10-02
| | | | | | | | | | | | | | | | | | | | | | | As part of an SMP cleanliness pass over UML, I consted a bunch of structures in order to not have to document their locking. One of these structures was a struct tty_operations. In order to const it in UML without introducing compiler complaints, the declaration of tty_set_operations needs to be changed, and then all of its callers need to be fixed. This patch declares all struct tty_operations in the tree as const. In all cases, they are static and used only as input to tty_set_operations. As an extra check, I ran an i386 allyesconfig build which produced no extra warnings. 53 drivers are affected. I checked the history of a bunch of them, and in most cases, there have been only a handful of maintenance changes in the last six months. serial_core.c was the busiest one that I looked at. Signed-off-by: Jeff Dike <jdike@addtoit.com> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpcLinus Torvalds2006-09-22
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (114 commits) [POWERPC] Fix ohare IDE irq workaround on old powermacs [POWERPC] EEH: Power4 systems sometimes need multiple resets. [POWERPC] Include <asm/mmu.h> in arch/powerpc/sysdev/fsl_soc.h for phys_addr_t. [POWERPC] Demacrofy arch/powerpc/platforms/maple/pci.c [POWERPC] Maple U3 HT - reject inappropriate config space access [POWERPC] Fix IPIC pending register assignments [POWERPC] powerpc: fix building gdb against asm/ptrace.h [POWERPC] Remove DISCONTIGMEM cruft from page.h [POWERPC] Merge iSeries i/o operations with the rest [POWERPC] 40x: Fix debug status register defines [POWERPC] Fix compile error in sbc8560 [POWERPC] EEH: support MMIO enable recovery step [POWERPC] EEH: enable MMIO/DMA on frozen slot [POWERPC] EEH: code comment cleanup [POWERPC] EEH: balance pcidev_get/put calls [POWERPC] PPC: Fix xmon stack frame address in backtrace [POWERPC] Add AT_PLATFORM value for Xilinx Virtex-4 FX [POWERPC] Start arch/powerpc/boot code reorganization [POWERPC] Define of_read_ulong helper [POWERPC] iseries: eliminate a couple of warnings ...
| * [POWERPC] Quiet hvc_console console output on failed opensOlof Johansson2006-09-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No other tty driver will print on the console when the open of it fails. On systems that happen to be configured for both ttyS0 and hvc0 console, this will keep flooding the console output. This is most likely to happen with systems booted between with and without hypervisor from the same filesystem. Let's just remove it. When it's really needed (i.e. when the open fails and someone is trying to debug it), noone will see the output anyway. And init will report the opens failing in due time through the syslog. Signed-off-by: Olof Johansson <olof@lixom.net> Acked-by: Ryan S. Arnold <rsa@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
| * [POWERPC] Make the hvc_console output buffer size settableStephen Rothwell2006-07-13
| | | | | | | | | | | | | | | | So the iSeries console will be faster since it can send up to 200 bytes at a time to the Hypervisor. This only affects the tty part of the console, the console writes are still in 16 byte lots. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
* | [PATCH] hvc_console suspend fixAndrew Morton2006-09-16
|/ | | | | | | | Fix http://bugzilla.kernel.org/show_bug.cgi?id=7152 Cc: Michael Tautschnig <tautschn@model.in.tum.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] irq-flags: drivers/char: Use the new IRQF_ constantsThomas Gleixner2006-07-02
| | | | | | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: "David S. Miller" <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-30
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] devfs: Remove the tty_driver devfs_name field as it's no longer neededGreg Kroah-Hartman2006-06-26
| | | | | | Also fixes all drivers that set this field. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [PATCH] powerpc: Make rtas console _much_ fasterMichael Ellerman2006-06-09
| | | | | | | | | | | | | | | | | | | | | | | | Currently the hvc_rtas driver is painfully slow to use. Our "benchmark" is ls -R /etc, which spits out about 27866 characters. The theoretical maximum speed would be about 2.2 seconds, the current code takes ~50 seconds. The core of the problem is that sometimes when the tty layer asks us to push characters the firmware isn't able to handle some or all of them, and so returns an error. The current code sees this and just returns to the tty code with the buffer half sent. The khvcd thread will eventually wake up and try to push more characters, which will usually work because by then the firmware's had time to make room. But the khvcd thread only wakes up every 10 milliseconds, which isn't fast enough. So change the khvcd thread logic so that if there's an incomplete write we yield() and then immediately try writing again. Doing so makes POLL_QUICK and POLL_WRITE synonymous, so remove POLL_QUICK. With this patch our "benchmark" takes ~2.8 seconds. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] powerpc: hvc_console updatesRyan S. Arnold2006-03-28
| | | | | | | | | | | | | | | | These are some updates from both Ryan and Arnd for the hvc_console driver: The main point is to enable the inclusion of a console driver for rtas, which is currrently needed for the cell platform. Also shuffle around some data-type declarations and moves some functions out of include/asm-ppc64/hvconsole.h and into a new drivers/char/hvc_console.h file. Signed-off-by: "Ryan S. Arnold" <rsa@us.ibm.com> Signed-off-by: Arnd Bergmann <abergman@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] powerpc: HVC init raceMichael Neuling2006-03-26
| | | | | | | | | | | I've been hitting a crash on boot where tty_open is being called before the hvc console driver setup is complete. This fixes the problem. Thanks to benh for his help on this. Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] Fix race condition in hvc console.Michal Ostrowski2006-02-23
| | | | | | | | | | | | | | | tty_schedule_flip() would schedule a thread that would call flush_to_ldisc(). If tty_buffer_request_room() gets called prior to that thread running -- which is likely in this loop in hvc_poll(), it would set the active flag in the tty buffer and consequently flush_to_ldisc() would ignore it. The result is that input on the hvc console is not processed. This fix calls tty_flip_buffer_push (and flags the tty as "low_latency"). The push to the ldisc thus happens synchronously. Signed-off-by: Michal Ostrowski <mostrows@watson.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] TTY layer buffering revampAlan Cox2006-01-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The API and code have been through various bits of initial review by serial driver people but they definitely need to live somewhere for a while so the unconverted drivers can get knocked into shape, existing drivers that have been updated can be better tuned and bugs whacked out. This replaces the tty flip buffers with kmalloc objects in rings. In the normal situation for an IRQ driven serial port at typical speeds the behaviour is pretty much the same, two buffers end up allocated and the kernel cycles between them as before. When there are delays or at high speed we now behave far better as the buffer pool can grow a bit rather than lose characters. This also means that we can operate at higher speeds reliably. For drivers that receive characters in blocks (DMA based, USB and especially virtualisation) the layer allows a lot of driver specific code that works around the tty layer with private secondary queues to be removed. The IBM folks need this sort of layer, the smart serial port people do, the virtualisers do (because a virtualised tty typically operates at infinite speed rather than emulating 9600 baud). Finally many drivers had invalid and unsafe attempts to avoid buffer overflows by directly invoking tty methods extracted out of the innards of work queue structs. These are no longer needed and all go away. That fixes various random hangs with serial ports on overflow. The other change in here is to optimise the receive_room path that is used by some callers. It turns out that only one ldisc uses receive room except asa constant and it updates it far far less than the value is read. We thus make it a variable not a function call. I expect the code to contain bugs due to the size alone but I'll be watching and squashing them and feeding out new patches as it goes. Because the buffers now dynamically expand you should only run out of buffering when the kernel runs out of memory for real. That means a lot of the horrible hacks high performance drivers used to do just aren't needed any more. Description: tty_insert_flip_char is an old API and continues to work as before, as does tty_flip_buffer_push() [this is why many drivers dont need modification]. It does now also return the number of chars inserted There are also tty_buffer_request_room(tty, len) which asks for a buffer block of the length requested and returns the space found. This improves efficiency with hardware that knows how much to transfer. and tty_insert_flip_string_flags(tty, str, flags, len) to insert a string of characters and flags For a smart interface the usual code is len = tty_request_buffer_room(tty, amount_hardware_says); tty_insert_flip_string(tty, buffer_from_card, len); More description! At the moment tty buffers are attached directly to the tty. This is causing a lot of the problems related to tty layer locking, also problems at high speed and also with bursty data (such as occurs in virtualised environments) I'm working on ripping out the flip buffers and replacing them with a pool of dynamically allocated buffers. This allows both for old style "byte I/O" devices and also helps virtualisation and smart devices where large blocks of data suddenely materialise and need storing. So far so good. Lots of drivers reference tty->flip.*. Several of them also call directly and unsafely into function pointers it provides. This will all break. Most drivers can use tty_insert_flip_char which can be kept as an API but others need more. At the moment I've added the following interfaces, if people think more will be needed now is a good time to say int tty_buffer_request_room(tty, size) Try and ensure at least size bytes are available, returns actual room (may be zero). At the moment it just uses the flipbuf space but that will change. Repeated calls without characters being added are not cumulative. (ie if you call it with 1, 1, 1, and then 4 you'll have four characters of space. The other functions will also try and grow buffers in future but this will be a more efficient way when you know block sizes. int tty_insert_flip_char(tty, ch, flag) As before insert a character if there is room. Now returns 1 for success, 0 for failure. int tty_insert_flip_string(tty, str, len) Insert a block of non error characters. Returns the number inserted. int tty_prepare_flip_string(tty, strptr, len) Adjust the buffer to allow len characters to be added. Returns a buffer pointer in strptr and the length available. This allows for hardware that needs to use functions like insl or mencpy_fromio. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hvc_console: start kernel thread before registering ttyAnton Blanchard2005-09-14
| | | | | | | | | | | | | | | Its possible that we can write to the hvc_console tty as soon it is registered. Recently this started happening due to (what looks like) a change to the hotplug code. Unfortunately at this stage we have not started the khvcd kernel thread and oops. The solution is to start the kernel thread before registering the tty. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hvc_console: Register ops when setting up hvc_consoleMilton Miller2005-07-07
| | | | | | | | | | | | When registering the hvc console port, register a list of ops (read and write) to go with it, instead of calling fixed function names. This allows different ports to encode the data differently. Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hvc_console: Separate hvc_console and vio code 2Milton Miller2005-07-07
| | | | | | | | | | | | Remove all the vio device driver code from hvc_console.c This will allow us to separate hvsi, hvc, and allow hvc_console to be used without the ppc64 vio layer. Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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