linux-toradex.git/drivers/tty/hvc, branch v5.18

tty: hvc: fix return value of __setup handler

2022-03-18T12:09:57+00:00

__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

serial: make uart_console_write->putchar()'s character an unsigned char

2022-03-03T14:06:31+00:00

Currently, uart_console_write->putchar's second parameter (the
character) is of type int. It makes little sense, provided uart_console_write()
accepts the input string as "const char *s" and passes its content -- the
characters -- to putchar(). So switch the character's type to unsigned
char.

We don't use char as that is signed on some platforms. That would cause
troubles for drivers which (implicitly) cast the char to u16 when
writing to the device. Sign extension would happen in that case and the
value written would be completely different to the provided char. DZ is
an example of such a driver -- on MIPS, it uses u16 for dz_out in
dz_console_putchar().

Note we do the char -> uchar conversion implicitly in
uart_console_write(). Provided we do not change size of the data type,
sign extension does not happen there, so the problem is void.

This makes the types consistent and unified with the rest of the uart
layer, which uses unsigned char in most places already. One exception is
xmit_buf, but that is going to be converted later.

Cc: Paul Cercueil 
Cc: Tobias Klauser 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Nicolas Ferre 
Cc: Alexandre Belloni 
Cc: Ludovic Desroches 
Cc: Florian Fainelli 
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: "Maciej W. Rozycki" 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Pengutronix Kernel Team 
Cc: Fabio Estevam 
Cc: NXP Linux Team 
Cc: Karol Gugala 
Cc: Mateusz Holenko 
Cc: Vladimir Zapolskiy 
Cc: Neil Armstrong 
Cc: Kevin Hilman 
Cc: Jerome Brunet 
Cc: Martin Blumenstingl 
Cc: Taichi Sugaya 
Cc: Takao Orito 
Cc: Liviu Dudau 
Cc: Sudeep Holla 
Cc: Lorenzo Pieralisi 
Cc: "Andreas Färber" 
Cc: Manivannan Sadhasivam 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Andy Gross 
Cc: Bjorn Andersson 
Cc: Krzysztof Kozlowski 
Cc: Orson Zhai 
Cc: Baolin Wang 
Cc: Chunyan Zhang 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: "David S. Miller" 
Cc: Peter Korsgaard 
Cc: Michal Simek 
Acked-by: Richard Genoud  [atmel_serial]
Acked-by: Uwe Kleine-König 
Acked-by: Paul Cercueil 
Acked-by: Neil Armstrong  # meson_serial
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

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