kernel/linux.git/drivers/tty/hvc, branch v6.6.132

tty: hvc_console: Call hvc_kick in hvc_write unconditionally

2025-09-19T14:32:05+00:00

commit cfd956dcb101aa3d25bac321fae923323a47c607 upstream. After hvc_write completes, call hvc_kick also in the case the output buffer has been drained, to ensure tty_wakeup gets called. This fixes that functions which wait for a drained buffer got stuck occasionally. Cc: stable Closes: https://bugzilla.opensuse.org/show_bug.cgi?id=1230062 Signed-off-by: Fabian Vogt Link: https://lore.kernel.org/r/2011735.PYKUYFuaPT@fvogt-thinkpad Signed-off-by: Greg Kroah-Hartman

hvc/xen: fix event channel handling for secondary consoles

2023-11-28T17:19:57+00:00

commit ef5dd8ec88ac11e8e353164407d55b73c988b369 upstream. The xencons_connect_backend() function allocates a local interdomain event channel with xenbus_alloc_evtchn(), then calls bind_interdomain_evtchn_to_irq_lateeoi() to bind to that port# on the *remote* domain. That doesn't work very well: (qemu) device_add xen-console,id=con1,chardev=pty0 [ 44.323872] xenconsole console-1: 2 xenbus_dev_probe on device/console/1 [ 44.323995] xenconsole: probe of console-1 failed with error -2 Fix it to use bind_evtchn_to_irq_lateeoi(), which does the right thing by just binding that *local* event channel to an irq. The backend will do the interdomain binding. This didn't affect the primary console because the setup for that is special — the toolstack allocates the guest event channel and the guest discovers it with HVMOP_get_param. Fixes: fe415186b43d ("xen/console: harden hvc_xen against event channel storms") Signed-off-by: David Woodhouse Reviewed-by: Juergen Gross Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231020161529.355083-2-dwmw2@infradead.org Signed-off-by: Greg Kroah-Hartman

hvc/xen: fix error path in xen_hvc_init() to always register frontend driver

2023-11-28T17:19:57+00:00

commit 2704c9a5593f4a47620c12dad78838ca62b52f48 upstream. The xen_hvc_init() function should always register the frontend driver, even when there's no primary console — as there may be secondary consoles. (Qemu can always add secondary consoles, but only the toolstack can add the primary because it's special.) Signed-off-by: David Woodhouse Reviewed-by: Juergen Gross Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231020161529.355083-3-dwmw2@infradead.org Signed-off-by: Greg Kroah-Hartman

hvc/xen: fix console unplug

2023-11-28T17:19:57+00:00

commit a30badfd7c13fc8763a9e10c5a12ba7f81515a55 upstream. On unplug of a Xen console, xencons_disconnect_backend() unconditionally calls free_irq() via unbind_from_irqhandler(), causing a warning of freeing an already-free IRQ: (qemu) device_del con1 [ 32.050919] ------------[ cut here ]------------ [ 32.050942] Trying to free already-free IRQ 33 [ 32.050990] WARNING: CPU: 0 PID: 51 at kernel/irq/manage.c:1895 __free_irq+0x1d4/0x330 It should be using evtchn_put() to tear down the event channel binding, and let the Linux IRQ side of it be handled by notifier_del_irq() through the HVC code. On which topic... xencons_disconnect_backend() should call hvc_remove() *first*, rather than tearing down the event channel and grant mapping while they are in use. And then the IRQ is guaranteed to be freed by the time it's torn down by evtchn_put(). Since evtchn_put() also closes the actual event channel, avoid calling xenbus_free_evtchn() except in the failure path where the IRQ was not successfully set up. However, calling hvc_remove() at the start of xencons_disconnect_backend() still isn't early enough. An unplug request is indicated by the backend setting its state to XenbusStateClosing, which triggers a notification to xencons_backend_changed(), which... does nothing except set its own frontend state directly to XenbusStateClosed without *actually* tearing down the HVC device or, you know, making sure it isn't actively in use. So the backend sees the guest frontend set its state to XenbusStateClosed and stops servicing the interrupt... and the guest spins for ever in the domU_write_console() function waiting for the ring to drain. Fix that one by calling hvc_remove() from xencons_backend_changed() before signalling to the backend that it's OK to proceed with the removal. Tested with 'dd if=/dev/zero of=/dev/hvc1' while telling Qemu to remove the console device. Signed-off-by: David Woodhouse Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231020161529.355083-4-dwmw2@infradead.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

tty: hvc: convert counts to size_t

2023-08-11T19:12:47+00:00

Unify the type of tty_operations::write() counters with the 'count' parameter. I.e. use size_t for them. Signed-off-by: "Jiri Slaby (SUSE)" Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20230810091510.13006-33-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: make tty_operations::write()'s count size_t

2023-08-11T19:12:46+00:00

Unify with the rest of the code. Use size_t for counts and ssize_t for retval. Signed-off-by: "Jiri Slaby (SUSE)" Link: https://lore.kernel.org/r/20230810091510.13006-30-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: propagate u8 data to tty_operations::write()

2023-08-11T19:12:46+00:00

Data are now typed as u8. Propagate this change to tty_operations::write(). Signed-off-by: "Jiri Slaby (SUSE)" Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Geert Uytterhoeven Cc: Richard Weinberger Cc: Anton Ivanov Cc: Johannes Berg Cc: Chris Zankel Cc: Max Filippov Cc: Arnd Bergmann Cc: Vaibhav Gupta Cc: Jens Taprogge Cc: Karsten Keil Cc: Scott Branden Cc: Ulf Hansson Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Sven Schnelle Cc: David Lin Cc: Johan Hovold Cc: Alex Elder Cc: Laurentiu Tudor Cc: Jiri Kosina Cc: David Sterba Cc: Shawn Guo Cc: Sascha Hauer Cc: Pengutronix Kernel Team Cc: Fabio Estevam Cc: NXP Linux Team Cc: Arnaud Pouliquen Cc: Oliver Neukum Cc: Mathias Nyman Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Link: https://lore.kernel.org/r/20230810091510.13006-28-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: hvsi: remove an extra variable from hvsi_write()

2023-07-31T15:16:05+00:00

'source' is the same as 'buf'. Rename the parameter ('buf') to 'source' and drop the local variable. Likely, the two were introduced to have a different type. But 'char' and 'unsigned char' are the same in the kernel for a long time. Signed-off-by: Jiri Slaby (SUSE) Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20230731080244.2698-4-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: Explicitly include correct DT includes

2023-07-25T18:19:05+00:00

The DT of_device.h and of_platform.h date back to the separate of_platform_bus_type before it as merged into the regular platform bus. As part of that merge prepping Arm DT support 13 years ago, they "temporarily" include each other. They also include platform_device.h and of.h. As a result, there's a pretty much random mix of those include files used throughout the tree. In order to detangle these headers and replace the implicit includes with struct declarations, users need to explicitly include the correct includes. Signed-off-by: Rob Herring Acked-by: Uwe Kleine-König # for imx Link: https://lore.kernel.org/r/20230724205440.767071-1-robh@kernel.org Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus-6.3-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2023-03-24T16:44:43+00:00

Pull xen fixes from Juergen Gross: - fix build warning - avoid concurrent accesses to the Xen PV console ring page * tag 'for-linus-6.3-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: x86/PVH: avoid 32-bit build warning when obtaining VGA console info hvc/xen: prevent concurrent accesses to the shared ring