linux-stable.git/drivers/tty/hvc, branch linux-5.17.y

tty: hvc: fix return value of __setup handler

2022-04-08T11:58:30+00:00

[ Upstream commit 53819a0d97aace1425bb042829e3446952a9e8a9 ]

__setup() handlers should return 1 to indicate that the boot option
has been handled or 0 to indicate that it was not handled.
Add a pr_warn() message if the option value is invalid and then
always return 1.

Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Fixes: 86b40567b917 ("tty: replace strict_strtoul() with kstrtoul()")
Cc: Jingoo Han 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Michael Ellerman 
Cc: Julian Wiedmann 
Cc: Vasily Gorbik 
Cc: linuxppc-dev@lists.ozlabs.org
Reported-by: Igor Zhbanov 
Signed-off-by: Randy Dunlap 
Link: https://lore.kernel.org/r/20220308024228.20477-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

xen/console: harden hvc_xen against event channel storms

2021-12-16T07:24:08+00:00

The Xen console driver is still vulnerable for an attack via excessive
number of events sent by the backend. Fix that by using a lateeoi event
channel.

For the normal domU initial console this requires the introduction of
bind_evtchn_to_irq_lateeoi() as there is no xenbus device available
at the time the event channel is bound to the irq.

As the decision whether an interrupt was spurious or not requires to
test for bytes having been read from the backend, move sending the
event into the if statement, as sending an event without having found
any bytes to be read is making no sense at all.

This is part of XSA-391

Signed-off-by: Juergen Gross 
Reviewed-by: Jan Beulich 
---
V2:
- slightly adapt spurious irq detection (Jan Beulich)
V3:
- fix spurious irq detection (Jan Beulich)

xen: flag hvc_xen to be not essential for system boot

2021-11-23T19:42:08+00:00

The Xen pv console driver is not essential for boot. Set the respective
flag.

Signed-off-by: Juergen Gross 
Reviewed-by: Boris Ostrovsky 
Link: https://lore.kernel.org/r/20211022064800.14978-4-jgross@suse.com
Signed-off-by: Boris Ostrovsky

Revert "tty: hvc: pass DMA capable memory to put_chars()"

2021-10-26T06:48:09+00:00

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 
Cc: Xianting Tian 
Cc: Shile Zhang 
Signed-off-by: Greg Kroah-Hartman

tty: hvc: pass DMA capable memory to put_chars()

2021-10-21T08:34:33+00:00

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 
Signed-off-by: Shile Zhang 
Link: https://lore.kernel.org/r/20211015024658.1353987-3-xianting.tian@linux.alibaba.com
Signed-off-by: Greg Kroah-Hartman

tty: hvc: use correct dma alignment size

2021-10-21T08:34:30+00:00

Use L1_CACHE_BYTES as the dma alignment size, use 'sizeof(long)' as
dma alignment is wrong.

Signed-off-by: Xianting Tian 
Signed-off-by: Shile Zhang 
Link: https://lore.kernel.org/r/20211015024658.1353987-2-xianting.tian@linux.alibaba.com
Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus-5.15b-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2021-10-08T19:55:23+00:00

Pull xen fixes from Juergen Gross:

 - fix two minor issues in the Xen privcmd driver plus a cleanup patch
   for that driver

 - fix multiple issues related to running as PVH guest and some related
   earlyprintk fixes for other Xen guest types

 - fix an issue introduced in 5.15 the Xen balloon driver

* tag 'for-linus-5.15b-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/balloon: fix cancelled balloon action
  xen/x86: adjust data placement
  x86/PVH: adjust function/data placement
  xen/x86: hook up xen_banner() also for PVH
  xen/x86: generalize preferred console model from PV to PVH Dom0
  xen/x86: make "earlyprintk=xen" work for HVM/PVH DomU
  xen/x86: allow "earlyprintk=xen" to work for PV Dom0
  xen/x86: make "earlyprintk=xen" work better for PVH Dom0
  xen/x86: allow PVH Dom0 without XEN_PV=y
  xen/x86: prevent PVH type from getting clobbered
  xen/privcmd: drop "pages" parameter from xen_remap_pfn()
  xen/privcmd: fix error handling in mmap-resource processing
  xen/privcmd: replace kcalloc() by kvcalloc() when allocating empty pages

xen/x86: make "earlyprintk=xen" work for HVM/PVH DomU

2021-10-05T06:36:05+00:00

xenboot_write_console() is dealing with these quite fine so I don't see
why xenboot_console_setup() would return -ENOENT in this case.

Adjust documentation accordingly.

Signed-off-by: Jan Beulich 
Reviewed-by: Juergen Gross 

Link: https://lore.kernel.org/r/3d212583-700e-8b2d-727a-845ef33ac265@suse.com
Signed-off-by: Juergen Gross

xen/x86: make "earlyprintk=xen" work better for PVH Dom0

2021-10-05T06:36:00+00:00

The xen_hvm_early_write() path better wouldn't be taken in this case;
while port 0xE9 can be used, the hypercall path is quite a bit more
efficient. Put that first, as it may also work for DomU-s (see also
xen_raw_console_write()).

While there also bail from the function when the first
domU_write_console() failed - later ones aren't going to succeed.

Signed-off-by: Jan Beulich 
Reviewed-by: Juergen Gross 

Link: https://lore.kernel.org/r/4fd89dcb-cfc5-c740-2e94-bb271e432d3e@suse.com
Signed-off-by: Juergen Gross

tty: drop put_tty_driver

2021-07-27T10:17:21+00:00

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 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Geert Uytterhoeven 
Cc: Jeff Dike 
Cc: Richard Weinberger 
Cc: Anton Ivanov 
Cc: Chris Zankel 
Cc: Max Filippov 
Cc: Arnd Bergmann 
Cc: Greg Kroah-Hartman 
Cc: Samuel Iglesias Gonsalvez 
Cc: Jens Taprogge 
Cc: Karsten Keil 
Cc: Scott Branden 
Cc: Ulf Hansson 
Cc: "David S. Miller" 
Cc: Jakub Kicinski 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Christian Borntraeger 
Cc: David Lin 
Cc: Johan Hovold 
Cc: Alex Elder 
Cc: Jiri Slaby 
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: Oliver Neukum 
Cc: Felipe Balbi 
Cc: Mathias Nyman 
Cc: Marcel Holtmann 
Cc: Johan Hedberg 
Cc: Luiz Augusto von Dentz 
Acked-by: Alex Elder 
Acked-by: Christian Borntraeger 
Acked-by: Max Filippov 
Acked-by: David Sterba 
Acked-by: Samuel Iglesias Gonsálvez 
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210723074317.32690-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman