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path: root/drivers/tty/hvc/hvc_console.c
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2021-10-26Revert "tty: hvc: pass DMA capable memory to put_chars()"Greg Kroah-Hartman1-21/+15
This reverts commit 0986d7bc5598f5df30e3db777d00e73890c97627. It still has some issues and needs to be dropped at this point in time. Link: https://lore.kernel.org/r/208f7a41-a9fa-630c-cb44-c37c503f3a72@kernel.org Reported-by: Jiri Slaby <jirislaby@kernel.org> Cc: Xianting Tian <xianting.tian@linux.alibaba.com> Cc: Shile Zhang <shile.zhang@linux.alibaba.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21tty: hvc: pass DMA capable memory to put_chars()Xianting Tian1-15/+21
As well known, hvc backend can register its opertions to hvc backend. the operations contain put_chars(), get_chars() and so on. Some hvc backend may do dma in its operations. eg, put_chars() of virtio-console. But in the code of hvc framework, it may pass DMA incapable memory to put_chars() under a specific configuration, which is explained in commit c4baad5029(virtio-console: avoid DMA from stack): 1, c[] is on stack, hvc_console_print(): char c[N_OUTBUF] __ALIGNED__; cons_ops[index]->put_chars(vtermnos[index], c, i); 2, ch is on stack, static void hvc_poll_put_char(,,char ch) { struct tty_struct *tty = driver->ttys[0]; struct hvc_struct *hp = tty->driver_data; int n; do { n = hp->ops->put_chars(hp->vtermno, &ch, 1); } while (n <= 0); } Commit c4baad5029 is just the fix to avoid DMA from stack memory, which is passed to virtio-console by hvc framework in above code. But I think the fix is aggressive, it directly uses kmemdup() to alloc new buffer from kmalloc area and do memcpy no matter the memory is in kmalloc area or not. But most importantly, it should better be fixed in the hvc framework, by changing it to never pass stack memory to the put_chars() function in the first place. Otherwise, we still face the same issue if a new hvc backend using dma added in the furture. In this patch, add 'char cons_outbuf[]' as part of 'struct hvc_struct', so hp->cons_outbuf is no longer the stack memory, we can use it in above cases safely. We also add lock to protect cons_outbuf instead of using the global lock of hvc. Introduce another array(cons_hvcs[]) for hvc pointers next to the cons_ops[] and vtermnos[] arrays. With the array, we can easily find hvc's cons_outbuf and its lock. With the patch, we can revert the fix c4baad5029. Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com> Link: https://lore.kernel.org/r/20211015024658.1353987-3-xianting.tian@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21tty: hvc: use correct dma alignment sizeXianting Tian1-1/+1
Use L1_CACHE_BYTES as the dma alignment size, use 'sizeof(long)' as dma alignment is wrong. Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com> Link: https://lore.kernel.org/r/20211015024658.1353987-2-xianting.tian@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-27tty: drop put_tty_driverJiri Slaby1-1/+1
put_tty_driver() is an alias for tty_driver_kref_put(). There is no need for two exported identical functions, therefore switch all users of old put_tty_driver() to new tty_driver_kref_put() and remove the former for good. Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Cc: Jens Taprogge <jens.taprogge@taprogge.org> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Scott Branden <scott.branden@broadcom.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: David Lin <dtwlin@gmail.com> Cc: Johan Hovold <johan@kernel.org> Cc: Alex Elder <elder@kernel.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: NXP Linux Team <linux-imx@nxp.com> Cc: Oliver Neukum <oneukum@suse.com> Cc: Felipe Balbi <balbi@kernel.org> Cc: Mathias Nyman <mathias.nyman@intel.com> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Acked-by: Alex Elder <elder@linaro.org> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Acked-by: David Sterba <dsterba@suse.com> Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210723074317.32690-8-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-27tty: stop using alloc_tty_driverJiri Slaby1-4/+4
alloc_tty_driver was deprecated by tty_alloc_driver in commit 7f0bc6a68ed9 (TTY: pass flags to alloc_tty_driver) in 2012. I never got into eliminating alloc_tty_driver until now. So we still have two functions for allocating drivers which might be confusing. So get rid of alloc_tty_driver uses to eliminate it for good in the next patch. Note we need to switch return value checking as tty_alloc_driver uses ERR_PTR. And flags are now a parameter of tty_alloc_driver. Cc: Richard Henderson <rth@twiddle.net>(odd fixer:ALPHA PORT) Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Helge Deller <deller@gmx.de> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Cc: Jens Taprogge <jens.taprogge@taprogge.org> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Oliver Neukum <oneukum@suse.com> Cc: Felipe Balbi <balbi@kernel.org> Cc: Johan Hovold <johan@kernel.org> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Acked-by: David Sterba <dsterba@suse.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210723074317.32690-5-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-21tty: hvc_console: Remove the repeated words 'no' and 'from'Xiaofei Tan1-2/+2
Remove the repeated words 'no' and 'from', reported by checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1621565558-26118-1-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: make tty_operations::chars_in_buffer return uintJiri Slaby1-1/+1
tty_operations::chars_in_buffer is another hook which is expected to return values >= 0. So make it explicit by the return type too -- use unsigned int. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> Acked-by: David Sterba <dsterba@suse.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Cc: Jens Taprogge <jens.taprogge@taprogge.org> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: David Lin <dtwlin@gmail.com> Cc: Johan Hovold <johan@kernel.org> Cc: Alex Elder <elder@kernel.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Oliver Neukum <oneukum@suse.com> Cc: Felipe Balbi <balbi@kernel.org> Cc: Mathias Nyman <mathias.nyman@intel.com> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Link: https://lore.kernel.org/r/20210505091928.22010-27-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: make tty_operations::write_room return uintJiri Slaby1-1/+1
Line disciplines expect a positive value or zero returned from tty->ops->write_room (invoked by tty_write_room). So make this assumption explicit by using unsigned int as a return value. Both of tty->ops->write_room and tty_write_room. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> Acked-by: Alex Elder <elder@linaro.org> Acked-by: Max Filippov <jcmvbkbc@gmail.com> # xtensa Acked-by: David Sterba <dsterba@suse.com> Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Helge Deller <deller@gmx.de> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Chris Zankel <chris@zankel.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Cc: Jens Taprogge <jens.taprogge@taprogge.org> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Scott Branden <scott.branden@broadcom.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: David Lin <dtwlin@gmail.com> Cc: Johan Hovold <johan@kernel.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Oliver Neukum <oneukum@suse.com> Cc: Felipe Balbi <balbi@kernel.org> Cc: Mathias Nyman <mathias.nyman@intel.com> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Link: https://lore.kernel.org/r/20210505091928.22010-23-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-27tty: hvc_console, fix crashes on parallel open/closeJiri Slaby1-15/+8
hvc_open sets tty->driver_data to NULL when open fails at some point. Typically, the failure happens in hp->ops->notifier_add(). If there is a racing process which tries to open such mangled tty, which was not closed yet, the process will crash in hvc_open as tty->driver_data is NULL. All this happens because close wants to know whether open failed or not. But ->open should not NULL this and other tty fields for ->close to be happy. ->open should call tty_port_set_initialized(true) and close should check by tty_port_initialized() instead. So do this properly in this driver. So this patch removes these from ->open: * tty_port_tty_set(&hp->port, NULL). This happens on last close. * tty->driver_data = NULL. Dtto. * tty_port_put(&hp->port). This happens in shutdown and until now, this must have been causing a reference underflow, if I am not missing something. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: stable <stable@vger.kernel.org> Reported-and-tested-by: Raghavendra <rananta@codeaurora.org> Link: https://lore.kernel.org/r/20200526145632.13879-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-12Revert "tty: hvc: Fix data abort due to race in hvc_open"Greg Kroah-Hartman1-14/+2
This reverts commit e2bd1dcbe1aa34ff5570b3427c530e4332ecf0fe. In discussion on the mailing list, it has been determined that this is not the correct type of fix for this issue. Revert it so that we can do this correctly. Reported-by: Jiri Slaby <jslaby@suse.cz> Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20200428032601.22127-1-rananta@codeaurora.org Cc: Raghavendra Rao Ananta <rananta@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-28tty: hvc: Fix data abort due to race in hvc_openRaghavendra Rao Ananta1-2/+14
Potentially, hvc_open() can be called in parallel when two tasks calls open() on /dev/hvcX. In such a scenario, if the hp->ops->notifier_add() callback in the function fails, where it sets the tty->driver_data to NULL, the parallel hvc_open() can see this NULL and cause a memory abort. Hence, serialize hvc_open and check if tty->private_data is NULL before proceeding ahead. The issue can be easily reproduced by launching two tasks simultaneously that does nothing but open() and close() on /dev/hvcX. For example: $ ./simple_open_close /dev/hvc0 & ./simple_open_close /dev/hvc0 & Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org> Link: https://lore.kernel.org/r/20200428032601.22127-1-rananta@codeaurora.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-23tty: hvc: fix buffer overflow during hvc_alloc().Andrew Melnychenko1-9/+14
If there is a lot(more then 16) of virtio-console devices or virtio_console module is reloaded - buffers 'vtermnos' and 'cons_ops' are overflowed. In older kernels it overruns spinlock which leads to kernel freezing: https://bugzilla.redhat.com/show_bug.cgi?id=1786239 To reproduce the issue, you can try simple script that loads/unloads module. Something like this: while [ 1 ] do modprobe virtio_console sleep 2 modprobe -r virtio_console sleep 2 done Description of problem: Guest get 'Call Trace' when loading module "virtio_console" and unloading it frequently - clearly reproduced on kernel-4.18.0: [ 81.498208] ------------[ cut here ]------------ [ 81.499263] pvqspinlock: lock 0xffffffff92080020 has corrupted value 0xc0774ca0! [ 81.501000] WARNING: CPU: 0 PID: 785 at kernel/locking/qspinlock_paravirt.h:500 __pv_queued_spin_unlock_slowpath+0xc0/0xd0 [ 81.503173] Modules linked in: virtio_console fuse xt_CHECKSUM ipt_MASQUERADE xt_conntrack ipt_REJECT nft_counter nf_nat_tftp nft_objref nf_conntrack_tftp tun bridge stp llc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_tables_set nft_chain_nat_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 nft_chain_route_ipv6 nft_chain_nat_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack nft_chain_route_ipv4 ip6_tables nft_compat ip_set nf_tables nfnetlink sunrpc bochs_drm drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm i2c_piix4 pcspkr crct10dif_pclmul crc32_pclmul joydev ghash_clmulni_intel ip_tables xfs libcrc32c sd_mod sg ata_generic ata_piix virtio_net libata crc32c_intel net_failover failover serio_raw virtio_scsi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: virtio_console] [ 81.517019] CPU: 0 PID: 785 Comm: kworker/0:2 Kdump: loaded Not tainted 4.18.0-167.el8.x86_64 #1 [ 81.518639] Hardware name: Red Hat KVM, BIOS 1.12.0-5.scrmod+el8.2.0+5159+d8aa4d83 04/01/2014 [ 81.520205] Workqueue: events control_work_handler [virtio_console] [ 81.521354] RIP: 0010:__pv_queued_spin_unlock_slowpath+0xc0/0xd0 [ 81.522450] Code: 07 00 48 63 7a 10 e8 bf 64 f5 ff 66 90 c3 8b 05 e6 cf d6 01 85 c0 74 01 c3 8b 17 48 89 fe 48 c7 c7 38 4b 29 91 e8 3a 6c fa ff <0f> 0b c3 0f 0b 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 [ 81.525830] RSP: 0018:ffffb51a01ffbd70 EFLAGS: 00010282 [ 81.526798] RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000000 [ 81.528110] RDX: ffff9e66f1826480 RSI: ffff9e66f1816a08 RDI: ffff9e66f1816a08 [ 81.529437] RBP: ffffffff9153ff10 R08: 000000000000026c R09: 0000000000000053 [ 81.530732] R10: 0000000000000000 R11: ffffb51a01ffbc18 R12: ffff9e66cd682200 [ 81.532133] R13: ffffffff9153ff10 R14: ffff9e6685569500 R15: ffff9e66cd682000 [ 81.533442] FS: 0000000000000000(0000) GS:ffff9e66f1800000(0000) knlGS:0000000000000000 [ 81.534914] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 81.535971] CR2: 00005624c55b14d0 CR3: 00000003a023c000 CR4: 00000000003406f0 [ 81.537283] Call Trace: [ 81.537763] __raw_callee_save___pv_queued_spin_unlock_slowpath+0x11/0x20 [ 81.539011] .slowpath+0x9/0xe [ 81.539585] hvc_alloc+0x25e/0x300 [ 81.540237] init_port_console+0x28/0x100 [virtio_console] [ 81.541251] handle_control_message.constprop.27+0x1c4/0x310 [virtio_console] [ 81.542546] control_work_handler+0x70/0x10c [virtio_console] [ 81.543601] process_one_work+0x1a7/0x3b0 [ 81.544356] worker_thread+0x30/0x390 [ 81.545025] ? create_worker+0x1a0/0x1a0 [ 81.545749] kthread+0x112/0x130 [ 81.546358] ? kthread_flush_work_fn+0x10/0x10 [ 81.547183] ret_from_fork+0x22/0x40 [ 81.547842] ---[ end trace aa97649bd16c8655 ]--- [ 83.546539] general protection fault: 0000 [#1] SMP NOPTI [ 83.547422] CPU: 5 PID: 3225 Comm: modprobe Kdump: loaded Tainted: G W --------- - - 4.18.0-167.el8.x86_64 #1 [ 83.549191] Hardware name: Red Hat KVM, BIOS 1.12.0-5.scrmod+el8.2.0+5159+d8aa4d83 04/01/2014 [ 83.550544] RIP: 0010:__pv_queued_spin_lock_slowpath+0x19a/0x2a0 [ 83.551504] Code: c4 c1 ea 12 41 be 01 00 00 00 4c 8d 6d 14 41 83 e4 03 8d 42 ff 49 c1 e4 05 48 98 49 81 c4 40 a5 02 00 4c 03 24 c5 60 48 34 91 <49> 89 2c 24 b8 00 80 00 00 eb 15 84 c0 75 0a 41 0f b6 54 24 14 84 [ 83.554449] RSP: 0018:ffffb51a0323fdb0 EFLAGS: 00010202 [ 83.555290] RAX: 000000000000301c RBX: ffffffff92080020 RCX: 0000000000000001 [ 83.556426] RDX: 000000000000301d RSI: 0000000000000000 RDI: 0000000000000000 [ 83.557556] RBP: ffff9e66f196a540 R08: 000000000000028a R09: ffff9e66d2757788 [ 83.558688] R10: 0000000000000000 R11: 0000000000000000 R12: 646e61725f770b07 [ 83.559821] R13: ffff9e66f196a554 R14: 0000000000000001 R15: 0000000000180000 [ 83.560958] FS: 00007fd5032e8740(0000) GS:ffff9e66f1940000(0000) knlGS:0000000000000000 [ 83.562233] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 83.563149] CR2: 00007fd5022b0da0 CR3: 000000038c334000 CR4: 00000000003406e0 Signed-off-by: Andrew Melnychenko <andrew@daynix.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200414191503.3471783-1-andrew@daynix.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-10tty: hvc: hvc_write() fix break conditionNicholas Piggin1-1/+6
Commit 550ddadcc758 ("tty: hvc: hvc_write() may sleep") broke the termination condition in case the driver stops accepting characters. This can result in unnecessary polling of the busy driver. Restore it by testing the hvc_push return code. Tested-by: Matteo Croce <mcroce@redhat.com> Tested-by: Jason Gunthorpe <jgg@mellanox.com> Tested-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-10tty: hvc: hvc_poll() fix read loop batchingNicholas Piggin1-2/+22
Commit ec97eaad1383 ("tty: hvc: hvc_poll() break hv read loop") removes get_chars batching entirely, which slows down large console operations like paste -- virtio console "feels worse than a 9600 baud serial line," reports Matteo. This adds back batching in a more latency friendly way. If the caller can sleep then we try to fill the entire flip buffer, releasing the lock and scheduling between each iteration. If it can not sleep, then batches are limited to 128 bytes. Matteo confirms this fixes the performance problem. Latency testing the powerpc OPAL console with OpenBMC UART with a large paste shows about 0.25ms latency, which seems reasonable. 10ms latencies were typical for this case before the latency breaking work, so we still see most of the benefit. kopald-1204 0d.h. 5us : hvc_poll <-hvc_handle_interrupt kopald-1204 0d.h. 5us : __hvc_poll <-hvc_handle_interrupt kopald-1204 0d.h. 5us : _raw_spin_lock_irqsave <-__hvc_poll kopald-1204 0d.h. 5us : tty_port_tty_get <-__hvc_poll kopald-1204 0d.h. 6us : _raw_spin_lock_irqsave <-tty_port_tty_get kopald-1204 0d.h. 6us : _raw_spin_unlock_irqrestore <-tty_port_tty_get kopald-1204 0d.h. 6us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 7us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 7us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 36us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 36us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 36us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 65us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 65us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 66us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 94us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 95us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 95us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 124us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 124us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 125us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 154us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 154us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 154us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 183us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 184us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 184us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 213us : tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 213us : __tty_buffer_request_room <-__hvc_poll kopald-1204 0d.h. 213us+: opal_get_chars <-__hvc_poll kopald-1204 0d.h. 242us : _raw_spin_unlock_irqrestore <-__hvc_poll kopald-1204 0d.h. 242us : tty_flip_buffer_push <-__hvc_poll kopald-1204 0d.h. 243us : queue_work_on <-tty_flip_buffer_push kopald-1204 0d.h. 243us : tty_kref_put <-__hvc_poll kopald-1204 0d.h. 243us : hvc_kick <-hvc_handle_interrupt kopald-1204 0d.h. 243us : wake_up_process <-hvc_kick kopald-1204 0d.h. 244us : try_to_wake_up <-hvc_kick kopald-1204 0d.h. 244us : _raw_spin_lock_irqsave <-try_to_wake_up kopald-1204 0d.h. 244us : _raw_spin_unlock_irqrestore <-try_to_wake_up Reported-by: Matteo Croce <mcroce@redhat.com> Tested-by: Matteo Croce <mcroce@redhat.com> Tested-by: Jason Gunthorpe <jgg@mellanox.com> Tested-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-10tty: hvc: hvc_poll() fix read loop hangNicholas Piggin1-2/+5
Commit ec97eaad1383 ("tty: hvc: hvc_poll() break hv read loop") causes the virtio console to hang at times (e.g., if you paste a bunch of characters to it. The reason is that get_chars must return 0 before we can be sure the driver will kick or poll input again, but this change only scheduled a poll if get_chars had returned a full count. Change this to poll on any > 0 count. Reported-by: Matteo Croce <mcroce@redhat.com> Reported-by: Jason Gunthorpe <jgg@mellanox.com> Tested-by: Matteo Croce <mcroce@redhat.com> Tested-by: Jason Gunthorpe <jgg@mellanox.com> Tested-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-23tty: hvc: introduce the hv_ops.flush operation for hvc driversNicholas Piggin1-2/+33
Use .flush to wait for drivers to flush their console outside of the spinlock, to reduce lock/irq latencies. Flush the hvc console driver after each write, which can help messages make it out to the console after a crash. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-23tty: hvc: hvc_write() may sleepNicholas Piggin1-15/+21
Rework the hvc_write loop to drop and re-take the spinlock on each iteration, add a cond_resched. Don't bother with an initial hvc_push initially, which makes the logic simpler -- just do a hvc_push on each time around the loop. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-23tty: hvc: hvc_poll() may sleepNicholas Piggin1-2/+14
Introduce points where hvc_poll drops the lock, enables interrupts, and reschedules. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-23tty: hvc: hvc_poll() break hv read loopNicholas Piggin1-43/+45
Avoid looping with the spinlock held while there is read data being returned from the hv driver. Instead note if the entire size returned by tty_buffer_request_room was read, and request another read poll. This limits the critical section lengths, and provides more even service to other consoles in case there is a pathological condition. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-23tty: hvc: use mutex instead of spinlock for hvc_structs lockNicholas Piggin1-12/+11
This allows hvc operations to sleep under the lock. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-08tty: hvc: Remove redundant license textGreg Kroah-Hartman1-14/+0
Now that the SPDX tag is in all tty files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Jiri Slaby <jslaby@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Metcalf <cmetcalf@mellanox.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-08tty: add SPDX identifiers to all remaining files in drivers/tty/Greg Kroah-Hartman1-0/+1
It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/tty files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Jiri Slaby <jslaby@suse.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: James Hogan <jhogan@kernel.org> Cc: Rob Herring <robh@kernel.org> Cc: Eric Anholt <eric@anholt.net> Cc: Stefan Wahren <stefan.wahren@i2se.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ray Jui <rjui@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Joachim Eastwood <manabian@gmail.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Richard Genoud <richard.genoud@gmail.com> Cc: Alexander Shiyan <shc_work@mail.ru> Cc: Baruch Siach <baruch@tkos.co.il> Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: "Uwe Kleine-König" <kernel@pengutronix.de> Cc: Pat Gefre <pfg@sgi.com> Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Vladimir Zapolskiy <vz@mleia.com> Cc: Sylvain Lemieux <slemieux.tyco@gmail.com> Cc: Carlo Caione <carlo@caione.org> Cc: Kevin Hilman <khilman@baylibre.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Andy Gross <andy.gross@linaro.org> Cc: David Brown <david.brown@linaro.org> Cc: "Andreas Färber" <afaerber@suse.de> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Laxman Dewangan <ldewangan@nvidia.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Barry Song <baohua@kernel.org> Cc: Patrice Chotard <patrice.chotard@st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Korsgaard <jacmet@sunsite.dk> Cc: Timur Tabi <timur@tabi.org> Cc: Tony Prisk <linux@prisktech.co.nz> Cc: Michal Simek <michal.simek@xilinx.com> Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Jiri Slaby <jslaby@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-31tty/hvc_console: fix console lock ordering with spinlockDenis Kirjanov1-2/+2
hvc_remove() takes a spin lock first then acquires the console semaphore. This situation can easily lead to a deadlock scenario where we call scheduler with spin lock held. Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-10tty: Remove extra include in HVC console tty frameworkSergio Valverde1-1/+0
An extra "init.h" include is found in the HVC console code. As such, the extra line is deleted. Signed-off-by: Sergio Valverde <vlvrdv@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds1-1/+1
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-30tty: hvc_console: silence unintialized variable warningDan Carpenter1-1/+1
If ->get_char() returns a negative error code and that can mean that "ch" is uninitialized. The callers of this function expect NO_POLL_CHAR on error so let's return that. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-04-30tty: Replace TTY_THROTTLED bit tests with tty_throttled()Peter Hurley1-1/+1
Abstract TTY_THROTTLED bit tests with tty_throttled(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-18tty: Remove tty_wait_until_sent_from_close()Peter Hurley1-1/+1
tty_wait_until_sent_from_close() drops the tty lock while waiting for the tty driver to finish sending previously accepted data (ie., data remaining in its write buffer and transmit fifo). tty_wait_until_sent_from_close() was added by commit a57a7bf3fc7e ("TTY: define tty_wait_until_sent_from_close") to prevent the entire tty subsystem from being unable to open new ttys while waiting for one tty to close while output drained. However, since commit 0911261d4cb6 ("tty: Don't take tty_mutex for tty count changes"), holding a tty lock while closing does not prevent other ttys from being opened/closed/hung up, but only prevents lifetime event changes for the tty under lock. Holding the tty lock while waiting for output to drain does prevent parallel non-blocking opens (O_NONBLOCK) from advancing or returning while the tty lock is held. However, all parallel opens _already_ block even if the tty lock is dropped while closing and the parallel open advances. Blocking in open has been in mainline since at least 2.6.29 (see tty_port_block_til_ready(); note the test for O_NONBLOCK is _after_ the wait while ASYNC_CLOSING). IOW, before this patch a non-blocking open will sleep anyway for the _entire_ duration of a parallel hardware shutdown, and when it wakes, the error return will cause a release of its tty, and it will restart with a fresh attempt to open. Similarly with a blocking open that is already waiting; when it's woken, the hardware shutdown has already completed to ASYNC_INITIALIZED is not set, which forces a release and restart as well. So, holding the tty lock across the _entire_ close (which is what this patch does), even while waiting for output to drain, is equivalent to the current outcome wrt parallel opens. Cc: Alan Cox <alan@linux.intel.com> Cc: David Laight <David.Laight@aculab.com> CC: Arnd Bergmann <arnd@arndb.de> CC: Karsten Keil <isdn@linux-pingi.de> CC: linuxppc-dev@lists.ozlabs.org Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04drivers/tty: make hvc_console.c explicitly non-modularPaul Gortmaker1-17/+1
The Kconfig currently controlling compilation of this code is: drivers/tty/hvc/Kconfig:config HVC_DRIVER drivers/tty/hvc/Kconfig: bool ...meaning that it currently is not being built as a module by anyone. Lets remove the modular code that is essentially orphaned, so that when reading the driver there is no doubt it is builtin-only, even though someone bothered to comment that the code was not used. Unlike other changes, this driver binds in w/o using module_init, so we dont have init ordering concerns with this commit. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-10tty: hvc_console.c: move assignment out of if () blockGreg Kroah-Hartman1-1/+2
We should not be doing assignments within an if () block so fix up the code to not do this. change was created using Coccinelle. CC: Jiri Slaby <jslaby@suse.cz> CC: Tomoki Sekiyama <tomoki.sekiyama@hds.com> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-03Merge tag 'tty-3.16-rc1' of ↵Linus Torvalds1-1/+8
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty into next Pull tty/serial driver updates from Greg KH: "Here is the big tty / serial driver pull request for 3.16-rc1. A variety of different serial driver fixes and updates and additions, nothing huge, and no real major core tty changes at all. All have been in linux-next for a while" * tag 'tty-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (84 commits) Revert "serial: imx: remove the DMA wait queue" serial: kgdb_nmi: Improve console integration with KDB I/O serial: kgdb_nmi: Switch from tasklets to real timers serial: kgdb_nmi: Use container_of() to locate private data serial: cpm_uart: No LF conversion in put_poll_char() serial: sirf: Fix compilation failure console: Remove superfluous readonly check console: Use explicit pointer type for vc_uni_pagedir* fields vgacon: Fix & cleanup refcounting ARM: tty: Move HVC DCC assembly to arch/arm tty/hvc/hvc_console: Fix wakeup of HVC thread on hvc_kick() drivers/tty/n_hdlc.c: replace kmalloc/memset by kzalloc vt: emulate 8- and 24-bit colour codes. printk/of_serial: fix serial console cessation part way through boot. serial: 8250_dma: check the result of TX buffer mapping serial: uart: add hw flow control support configuration tty/serial: at91: add interrupts for modem control lines tty/serial: at91: use mctrl_gpio helpers tty/serial: Add GPIOLIB helpers for controlling modem lines ARM: at91: gpio: implement get_direction ...
2014-05-29tty/hvc/hvc_console: Fix wakeup of HVC thread on hvc_kick()Benjamin Herrenschmidt1-1/+8
Some backends call hvc_kick() to wakeup the HVC thread from its slumber upon incoming characters. This however doesn't work properly because it uses msleep_interruptible() which is mostly immune to wake_up_process(). It will basically go back to sleep until the timeout is expired (only signals can really wake it). Replace it with a simple shedule_timeout_interruptible() instead, which may wakeup earlier every now and then but we really don't care in this case. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-04drivers/tty/hvc: don't free hvc_console_setup after initTomoki Sekiyama1-1/+1
When 'console=hvc0' is specified to the kernel parameter in x86 KVM guest, hvc console is setup within a kthread. However, that will cause SEGV and the boot will fail when the driver is builtin to the kernel, because currently hvc_console_setup() is annotated with '__init'. This patch removes '__init' to boot the guest successfully with 'console=hvc0'. Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-13hvc: ensure hvc_init is only ever called once in hvc_console.cPaul Gortmaker1-1/+5
Commit 3e6c6f630a5282df8f3393a59f10eb9c56536d23 ("Delay creation of khcvd thread") moved the call of hvc_init from being a device_initcall into hvc_alloc, and used a non-null hvc_driver as indication of whether hvc_init had already been called. The problem with this is that hvc_driver is only assigned a value at the bottom of hvc_init, and so there is a window where multiple hvc_alloc calls can be in progress at the same time and hence try and call hvc_init multiple times. Previously the use of device_init guaranteed that hvc_init was only called once. This manifests itself as sporadic instances of two hvc_init calls racing each other, and with the loser of the race getting -EBUSY from tty_register_driver() and hence that virtual console fails: Couldn't register hvc console driver virtio-ports vport0p1: error -16 allocating hvc for port Here we add an atomic_t to guarantee we'll never run hvc_init twice. Cc: stable@vger.kernel.org # v2.6.24+ Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixes: 3e6c6f630a52 ("Delay creation of khcvd thread") Reported-by: Jim Somerville <Jim.Somerville@windriver.com> Tested-by: Jim Somerville <Jim.Somerville@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-17drivers: tty: Mark the function hvc_poll_init() as static in hvc_console.cRashika Kheria1-1/+1
Mark the function hvc_poll_init() as static in hvc/hvc_console.c because it is not used outside this file. This eliminates the following warning in hvc/hvc_console.c: drivers/tty/hvc/hvc_console.c:791:5: warning: no previous prototype for ‘hvc_poll_init’ [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-25tty/hvc_console: Add DTR/RTS callback to handle HUPCL controlHendrik Brueckner1-1/+10
Introduce a new callback to explicitly handle the HUPCL termios control flag. This prepares for a follow-up commit for the hvc_iucv device driver to improve handling when to drop an established network connection. The callback naming is based on the recently added tty_port interface to facilitate a potential refactoring of the hvc_console to use tty_port functions. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-16TTY: switch tty_flip_buffer_pushJiri Slaby1-1/+1
Now, we start converting tty buffer functions to actually use tty_port. This will allow us to get rid of the need of tty in many call sites. Only tty_port will needed and hence no more tty_port_tty_get in those paths. Now, the one where most of tty_port_tty_get gets removed: tty_flip_buffer_push. IOW we also closed all the races in drivers not using tty_port_tty_get at all yet. Also we move tty_flip_buffer_push declaration from include/linux/tty.h to include/linux/tty_flip.h to all others while we are changing it anyway. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-16TTY: switch tty_insert_flip_charJiri Slaby1-1/+1
Now, we start converting tty buffer functions to actually use tty_port. This will allow us to get rid of the need of tty in many call sites. Only tty_port will needed and hence no more tty_port_tty_get in those paths. tty_insert_flip_char is the next one to proceed. This one is used all over the code, so the patch is huge. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-16TTY: switch tty_buffer_request_room to tty_portJiri Slaby1-1/+1
Now, we start converting tty buffer functions to actually use tty_port. This will allow us to get rid of the need of tty pointer in many call sites. Only tty_port will be needed and hence no more tty_port_tty_get calls in those paths. Here we start with tty_buffer_request_room. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-15TTY: hvc_console, fix port reference count going to zero prematurelyPaul Mackerras1-7/+0
Commit bdb498c20040 "TTY: hvc_console, add tty install" took the port refcounting out of hvc_open()/hvc_close(), but failed to remove the kref_put() and tty_kref_put() calls in hvc_hangup() that were there to remove the extra references that hvc_open() had taken. The result was that doing a vhangup() when the current terminal was a hvc_console, then closing the current terminal, would end up calling destroy_hvc_struct() and making the port disappear entirely. This meant that Fedora 17 systems would boot up but then not display the login prompt on the console, and attempts to open /dev/hvc0 would give a "No such device" error. This fixes it by removing the extra kref_put() and tty_kref_put() calls. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-05Merge branch 'next' of ↵Linus Torvalds1-7/+26
git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc Pull powerpc updates from Benjamin Herrenschmidt: "Some highlights in addition to the usual batch of fixes: - 64TB address space support for 64-bit processes by Aneesh Kumar - Gavin Shan did a major cleanup & re-organization of our EEH support code (IBM fancy PCI error handling & recovery infrastructure) which paves the way for supporting different platform backends, along with some rework of the PCIe code for the PowerNV platform in order to remove home made resource allocations and instead use the generic code (which is possible after some small improvements to it done by Gavin). - Uprobes support by Ananth N Mavinakayanahalli - A pile of embedded updates from Freescale folks, including new SoC and board supports, more KVM stuff including preparing for 64-bit BookE KVM support, ePAPR 1.1 updates, etc..." Fixup trivial conflicts in drivers/scsi/ipr.c * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (146 commits) powerpc/iommu: Fix multiple issues with IOMMU pools code powerpc: Fix VMX fix for memcpy case driver/mtd:IFC NAND:Initialise internal SRAM before any write powerpc/fsl-pci: use 'Header Type' to identify PCIE mode powerpc/eeh: Don't release eeh_mutex in eeh_phb_pe_get powerpc: Remove tlb batching hack for nighthawk powerpc: Set paca->data_offset = 0 for boot cpu powerpc/perf: Sample only if SIAR-Valid bit is set in P7+ powerpc/fsl-pci: fix warning when CONFIG_SWIOTLB is disabled powerpc/mpc85xx: Update interrupt handling for IFC controller powerpc/85xx: Enable USB support in p1023rds_defconfig powerpc/smp: Do not disable IPI interrupts during suspend powerpc/eeh: Fix crash on converting OF node to edev powerpc/eeh: Lock module while handling EEH event powerpc/kprobe: Don't emulate store when kprobe stwu r1 powerpc/kprobe: Complete kprobe and migrate exception frame powerpc/kprobe: Introduce a new thread flag powerpc: Remove unused __get_user64() and __put_user64() powerpc/eeh: Global mutex to protect PE tree powerpc/eeh: Remove EEH PE for normal PCI hotplug ...
2012-09-17tty: Fix hvc returnAlan Cox1-1/+1
HVC returns a size of -1 bytes for the write room in some cases. This is bogus and not handled by the tty layer at all. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-05hvc_console: Better kernel console supportBenjamin Herrenschmidt1-7/+26
hvc_console has two methods to instanciate the consoles. hvc_instanciate is meant to be called at early boot, while hvc_alloc is called for more dynamically probed objects. Currently, it only deals with adding kernel consoles in the former case, which means for example that if a console only uses dynamic probing, it will never be usable as a kernel console even when specifying console=hvc0 explicitly, which could be considered annoying... More specifically, on pseries, we only do the early instanciate for the console currently used by the firmware, so if you have your firmware configured to go to a video card, for example, you cannot get your kernel console, oops messages, etc... on your serial port or hypervisor console, which would be handy to deal with oopses. This fixes it by checking if hvc_console.flags & CON_ENABLED is set when registering a new dynamic console, and if not, redo the index check and re-register the console if the index matches, allowing console=hvcN to work. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-08-14TTY: hvc_console, add tty installJiri Slaby1-6/+25
This has two outcomes: * we give the TTY layer a tty_port * we do not find the info structure every time open is called on that tty Since we take a reference to a port in ->install, we need also ->cleanup to drop that reference. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: linuxppc-dev@lists.ozlabs.org Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-13TTY: hvc, fix TTY refcountingJiri Slaby1-5/+0
A -next commit "TTY: HVC, use tty from tty_port" switched the driver to use tty_port helper for tty refcounting. But it omitted to remove manual tty refcounting from open, close and hangup. So now we are getting random crashes caused by use-after-free: Unable to handle kernel paging request for data at address 0xc0000003f9d550 Faulting instruction address: 0xc0000000001b7f40 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP: c0000000001b7f40 LR: c0000000001b7f14 CTR: c0000000000e04f0 ... NIP [c0000000001b7f40] .__kmalloc+0x70/0x230 LR [c0000000001b7f14] .__kmalloc+0x44/0x230 Call Trace: [c0000003f68bf930] [c0000003f68bf9b0] 0xc0000003f68bf9b0 (unreliable) [c0000003f68bf9e0] [c0000000001e5424] .alloc_fdmem+0x24/0x70 [c0000003f68bfa60] [c0000000001e54f8] .alloc_fdtable+0x88/0x130 [c0000003f68bfaf0] [c0000000001e5924] .dup_fd+0x384/0x450 [c0000003f68bfbd0] [c00000000009a310] .copy_process+0x880/0x11d0 [c0000003f68bfcd0] [c00000000009aee0] .do_fork+0x70/0x400 [c0000003f68bfdc0] [c0000000000141c4] .sys_clone+0x54/0x70 [c0000003f68bfe30] [c000000000009aa0] .ppc_clone+0x8/0xc Fix that by complete removal of tty_kref_get/put in open/close/hangup paths. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-and-tested-by: Michael Neuling <mikey@neuling.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: ppc-dev <linuxppc-dev@lists.ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09TTY: HVC, use count from tty_portJiri Slaby1-19/+21
Now, count is used from tty_port and protected by tty_port->lock. n_outbuf is left unprotected in hvc_hangup now, because there is no point to hold any lock, since other uses are unprotected too. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09TTY: HVC, use tty from tty_portJiri Slaby1-21/+15
The driver already used refcounting. So we just switch it to tty_port helpers. And switch to tty_port->lock for tty. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09TTY: HVC, add tty_portJiri Slaby1-9/+14
And use kref from that. This means we need tty_port->ops->destruct to properly free the structure. This is what destroy_hvc_struct used to do so we leverage that. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-08TTY: remove re-assignments to tty_driver membersJiri Slaby1-1/+0
All num, magic and owner are set by alloc_tty_driver. No need to re-set them on each allocation site. pti driver sets something different to what it passes to alloc_tty_driver. It is not a bug, since we don't use the lines parameter in any way. Anyway this is fixed, and now we do the right thing. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Tilman Schmidt <tilman@imap.cc> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2011-11-07Revert "hvc_console: display printk messages on console."Linus Torvalds1-6/+1
This reverts commit 361162459f62dc0826b82c9690a741a940f457f0. It causes an infinite loop when booting Linux under Xen, as so: [ 2.382984] console [hvc0] enabled [ 2.382984] console [hvc0] enabled [ 2.382984] console [hvc0] enabled ... as reported by Konrad Rzeszutek Wilk. And Rusty reports the same for lguest. He goes on to say: "This is not a concurrency problem: the issue seems to be that calling register_console() twice on the same struct console is a bad idea." and Greg says he'll fix it up properly at some point later. Revert for now. Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reported-by: Rusty Russell <rusty@ozlabs.org> Requested-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Miche Baker-Harvey <miche@google.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>