Commit Graph

482213 Commits

Author SHA1 Message Date
Hans de Goede
1ad7ed5af3 uas: Cleanup uas_log_cmd_state usage
Instead of doing:

uas_log_cmd_state(cmnd, __func__)
scmd_printk(KERN_ERR, cmnd, "error doing foo %d\n", err)

On error, resulting in 2 log calls for a single error, make uas_log_cmd_state
take a status code, and change calls like the above to:

uas_log_cmd_state(cmnd, "error doing foo", err)

Also change various sanity checks (which should never trigger) from:
"scmd_printk(KERN_ERR, cmnd, "sanity foo failed\n")" to calling the new
uas_log_cmd_state(), so that when they do trigger we get more info.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:12 -07:00
Hans de Goede
102c00cb91 uas: Remove protype hardware usb interface info
We've removed all hack from the driver for pre-production hardware.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:12 -07:00
Hans de Goede
5ad22cfc13 uas: Remove support for old sense ui as used in pre-production hardware
I've access to a number of different uas devices now, and none of them use
old style sense urbs. The only case where these code-paths trigger is with
the asm1051 and there they do the wrong thing, as the asm1051 sends 8 bytes
status iu-s when it does not have any sense data, but uses new style
sense iu-s regardless, as can be seen for scsi cmnds where there is sense
data.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:12 -07:00
Hans de Goede
eb7d664ae4 uas: Drop COMMAND_COMPLETED flag
It was only used to sanity check against completing the same cmnd twice,
but that is the case we're likely operating on free-ed memory, and doing
sanity checks on free-ed memory is not really helpful.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:12 -07:00
Hans de Goede
6dcd8ec240 uas: Use scsi_print_command
Use scsi_print_command to print commands during errors, rather then printing
the rather meaningless pointer to the command.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
51b361737b uas: Do not log urb status error on cancellation
Check for both type of cancellation codes for sense and data urbs.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
e5e558192f uas: Use streams on upcoming 10Gbps / 3.1 USB
Limit the no-streams case to speeds less then USB_SPEED_SUPER.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
f9dc024a2d uas: pre_reset and suspend: Fix a few races
The purpose of uas_pre_reset is to:

1) Stop any new commands from being submitted while an externally triggered
   usb-device-reset is running
2) Wait for any pending commands to finish before allowing the usb-device-reset
   to continue

The purpose of uas_suspend is to:
2) Wait for any pending commands to finish before suspending

This commit fixes races in both paths:

1) For 1) we use scsi_block_requests, but the scsi midlayer calls queuecommand
   without holding any locks, so a queuecommand may already past the midlayer
   scsi_block_requests checks when we call it, add a check to uas_queuecommand
   to fix this

2) For 2) we were waiting for all sense-urbs to complete, there are 2 problems
   with this approach:
a) data-urbs may complete after the sense urb, so we need to check for those
   too
b) if a sense-urb completes with a iu id of READ/WRITE_READY a command is not
   yet done. We submit a new sense-urb immediately in this case, but that
   submit may fail (in which case it will get retried by uas_do_work), if this
   happens the sense_urbs anchor may become empty while the cmnd is not yet
   done

Also unblock requests on timeout, to avoid things getting stuck in that case.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
4c5481efb4 uas: Fix memleak of non-submitted urbs
Not all urbs we've allocated are necessarily also submitted, non-submitted
urbs will not be free-ed by their completion handler. So we need to free
them manually.

There are 2 scenarios where this can happen:

1) We have failed to submit some urbs at abort / disconnect
2) When running over usb-2 we may have never tried to submit the data urbs
   when completing the scsi cmnd, because we never got a READ/WRITE_READY iu

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
616f0e6cab uas: Drop all references to a scsi_cmnd once it has been aborted
Do not keep references around to a cmnd which is under error handling.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
b6823c51fc uas: Remove cmnd reference from the cmd urb
It is not strictly necessary for the cmd urb to have a reference to the
cmnd, and without this reference it becomes easier to drop all references to
a cmnd on an abort.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
43cd99cb17 uas: Drop inflight list
We've the same info doubled in both the inflight list and the cmnd array,
drop the list.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
9c15c5738b uas: zap_pending: data urbs should have completed at this time
The data urbs are all killed before calling zap_pending, and their completion
handler should have cleared their inflight flag.

Do not 0 the data inflight flags, and add a check for try_complete succeeding,
as it should always succeed when called from zap_pending.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
1589349f74 uas: Simplify reset / disconnect handling
Drop the whole dance with first moving cmnds to a dead-list. The resetting
flag ensures that no new cmds / urbs will be submitted, and that any urb
completions are short-circuited without trying to complete the scsi cmnd.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:11 -07:00
Hans de Goede
85fea82554 uas: Free data urbs on completion
Now that we no longer drop our lock to unlink the data urbs, we can simply
free them on completion, making their handling consistent with the other urbs.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:10 -07:00
Hans de Goede
60d9f67d47 uas: Simplify unlink of data urbs on error
There is no need for all the trickery with dropping the lock, we can
simply reference the urbs while we hold the lock to ensure the urbs don't
disappear beneath us, and do the actual unlink (+ unreference) after we've
dropped the lock.

This also fixes a race where we may loose of cmnd ownership to the scsi
midlayer without holding the lock due to the midlayer re-claiming ownership
through an abort (which will be handled by a future patch in this series).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:10 -07:00
Hans de Goede
d89da03ace uas: Check against unexpected completions
The status urb should not complete before the command has been submitted, nor
should we get a second status urb for the same tag after a IU_ID_STATUS.

Data urbs should not complete before the command has been submitted, but may
complete after the IU_ID_STATUS.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:10 -07:00
Hans de Goede
5e61aede47 uas: Do not use scsi_host_find_tag
Using scsi_host_find_tag with tags returned by the device is unsafe for
multiple reasons:

1) It returns tags->rqs[tag], which may be non NULL even when the cmnd is
   not owned by us
2) It returns tags->rqs[tag], without holding any locks protecting it
3) It returns tags->rqs[tag], without doing any boundary checking

Instead keep our own list which maps tags -> inflight cmnds.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:10 -07:00
Hans de Goede
e0620001e4 uas: Add uas_get_tag() helper function
Factor out the mapping of scsi-tags -> uas-tags/stream-ids to a helper function
so that there is a single place where this "magic" happens.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:10 -07:00
Hans de Goede
b7b5d11fae uas: Fix resetting flag handling
- Make sure we always hold the lock when setting / checking resetting
- Check resetting before checking urb->status
- Add missing check for resetting to uas_data_cmplt
- Add missing check for resetting to uas_do_work

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:10 -07:00
Hans de Goede
5df2be6333 uas: Remove task-management / abort error handling code
There are various bug reports about oopses / hangs with the uas driver,
which all point to the abort-command and logical-unit-reset (task-management)
error handling paths.

Getting these right is very hard, there are quite a few corner cases, and
testing is almost impossible since under normal operation these code paths
are not used at all.

Another problem is that there are also some cases where it simply is not clear
what to do at all. E.g. over usb-2 multiple outstanding commands share the same
endpoint. What if a command gets aborted while its sense urb is half way
through completing (so some data has been transfered but not all). Since the
urb is not yet complete we don't know if the sense urb is actually for this
command, or for one of the other oustanding commands. If it is for one of the
other commands and we cancel it, then we end up in an undefined state. But if
it is actually for the command we're aborting, and the abort succeeds, then it
may never complete...

This exact same problem applies to logical unit resets too, if there are
multiple luns, then commands outstanding on both luns share the sense
endpoint. If there is only a single lun, then doing a logical unit reset is
little better then doing a full usb device reset.

So summarizing because:
1) abort / lun-reset is very tricky to get right
2) Not being able to test the tricky code, which means it will have bugs
3) This being a code path which under normal operation will never happen,
   so being slow / sub-optimal here is not really an issue
4) Under error conditions we will still be able to recover through usb
   device resets.
5) This may be a bit slower in some cases, but this is actually faster in
   cases where the bridge ship has locked up, which seems to be the most
   common error case sofar.

This commit removes the abort / lun-reset error handling paths, and also the
taks-mgmt code since those are the only 2 task-mgmt users. Leaving only the
(tested and testable) usb-device-reset error handling path in place.

Note I realize that this is somewhat of a big hammer, but currently people
are seeing very hard to debug oopses with uas. First let focus on making uas
work reliable, then we can later look into adding more fine grained error
handling.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:42:10 -07:00
Hans de Goede
710f1bf16a uas: Add another ASM1051 usb-id to the uas blacklist
As most ASM1051 based devices, this one has unfixable issues with uas too.

Cc: stable@vger.kernel.org # 3.16
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:40:48 -07:00
Hans de Goede
f9554a6b19 uas: Add US_FL_NO_ATA_1X quirk for Seagate (0bc2:ab20) drives
https://bbs.archlinux.org/viewtopic.php?pid=1457492

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:40:48 -07:00
Hans de Goede
734016b00b uas: Add no-report-opcodes quirk
Besides the ASM1051 (*) needing sdev->no_report_opcodes = 1, it turns out that
the JMicron JMS567 also needs it to work properly with uas (usb-storage always
sets it). Since some of the scsi devs were not to keen on the idea to
outrightly set sdev->no_report_opcodes = 1 for all uas devices, so add a quirk
for this, and set it for the JMS567.

*) Which has become a non-issue since we've completely blacklisted uas on
the ASM1051 for other reasons

Cc: stable@vger.kernel.org
Reported-and-tested-by: Claudio Bizzarri <claudio.bizzarri@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:40:48 -07:00
Hans de Goede
593078525c uas: Add a quirk for rejecting ATA_12 and ATA_16 commands
And set this quirk for the Seagate Expansion Desk (0bc2:2312), as that one
seems to hang upon receiving an ATA_12 or ATA_16 command.

https://bugzilla.kernel.org/show_bug.cgi?id=79511
https://bbs.archlinux.org/viewtopic.php?id=183190

While at it also add missing documentation for the u value for usb-storage
quirks.

Cc: stable@vger.kernel.org # 3.16, 3.17
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

--
Changes in v2: Add documentation for new t and u usb-storage.quirks flags
Changes in v3: Fix typo in documentation
Changes in v4: Also apply the quirk to (0bc2:3312)
Changes in v5: Rebased on 3.17-rc5, drop u documentation, already upstream
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:40:48 -07:00
Srinivas Kandagatla
fa9eb32418 drivers/soc: qcom: do not disable the iface clock in probe
since commit 31964ffebb ("tty: serial: msm: Remove direct access to GSBI")'
serial hangs if earlyprintk are enabled.

This hang is noticed only when the GSBI driver is probed and all the
earlyprintks before gsbi probe are seen on the console.
The reason why it hangs is because GSBI driver disables hclk in its
probe function without realizing that the serial IP might be in use by
a bootconsole. As gsbi driver disables the clock in probe the
bootconsole locks up.

Turning off hclk's could be dangerous if there are system components
like earlyprintk using the hclk.

This patch fixes the issue by delegating the clock management to
probe and remove functions in gsbi rather than disabling the clock in probe.

More detailed problem description can be found here:
http://www.spinics.net/lists/linux-arm-msm/msg10589.html

Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
2014-09-23 21:38:32 -07:00
Sanjeev Sharma
ab945eff83 uas: replace WARN_ON_ONCE() with lockdep_assert_held()
on some architecture spin_is_locked() always return false in
uniprocessor configuration and therefore it would be advise
to replace with lockdep_assert_held().

Signed-off-by: Sanjeev Sharma <Sanjeev_Sharma@mentor.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:38:08 -07:00
Peter Griffin
62f6f0863e MAINTAINERS: Add ehci-st.c and ohci-st.c to ARCH/STI architecture
This patch adds the ehci-st.c and ohci-st.c files for the usb 2.0
& usb1.1 host controller drivers found on stih41x and stih4xx STMicroelectronics
SoC's into the STI arch section of the maintainers file.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:36:20 -07:00
Peter Griffin
554405d459 usb: host: ohci-st: Add ohci-st devicetree bindings documentation
This patch documents the device tree bindings required for
the ohci on-chip controller found in ST consumer electronics SoC's.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:35:50 -07:00
Peter Griffin
fee1dc0282 usb: host: ehci-st: Add ehci-st devicetree bindings documentation
This patch documents the device tree bindings required for the
ehci on-chip controller found in ST consumer electronics SoC's.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:35:50 -07:00
Peter Griffin
d115837259 usb: host: ohci-st: Add OHCI driver support for ST STB devices
This patch adds the glue code required to ensure the on-chip OHCI
controller works on STi consumer electronics SoC's from STMicroelectronics.

It mainly manages the setting and enabling of the relevant clocks and manages
the reset / power signals to the IP block.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:35:50 -07:00
Peter Griffin
e47c5a0906 usb: host: ehci-st: Add EHCI support for ST STB devices
This patch adds the glue code required to ensure the on-chip EHCI
controller works on STi consumer electronics SoC's from STMicroelectronics.

It mainly manages the setting and enabling of the relevant clocks and manages
the reset / power signals to the IP block.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:35:50 -07:00
Tobias Klauser
ae7c798d6b USB: isp1362: Use devm_ioremap_resource
Use devm_ioremap_resource to simplify error handling in the probe
function and to get rid of some boilerplate in the remove function.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:33:10 -07:00
Peter Chen
b760017076 of: add vendor prefix for Chipidea
Adds chipidea to the list of DT vendor prefixes.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:32:31 -07:00
Peter Chen
19353881b4 usb: chipidea: enhance kernel-doc format
Some kernel-doc style comment are not satisfied for format, fix them.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:32:31 -07:00
Peter Chen
27c62c2da1 usb: chipidea: otg initialization is only needed when the gadget is supported
We have only needed to enable otg initialization when both of
below conditions are satisfied:

- The controller is otg capable
- The gadget function is enabled

If the controller is otg capable, but is host-only configuration, we do
not need to access register otgsc and do any otg operations (eg, create
otg workqueue).

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:32:31 -07:00
Stefan Agner
f40017e0f3 chipidea: usbmisc_imx: Add USB support for VF610 SoCs
This adds Vybrid VF610 SoC support. The IP is very similar to i.MX6,
however, the non-core registers are spread in two different register
areas. Hence we support multiple instances of the USB misc driver
and add the driver instance to the imx_usbmisc_data structure.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:32:30 -07:00
Peter Chen
c0e602dbf3 doc: dt-binding: ci-hdrc-imx: add TPL support
TPL (Targeted Peripheral List) is needed for targets host
(OTG and Embedded Hosts) for usb certification and other
vendor specific requirements.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:28:41 -07:00
Peter Chen
f6a9ff0783 usb: chipidea: add TPL support for targeted hosts
For OTG and Embedded hosts, they may need TPL (Targeted Peripheral List)
for usb certification and other vender specific requirements, the
platform can tell chipidea core driver if it supports tpl through DT
or platform data.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:28:41 -07:00
Peter Chen
05f8b35a62 usb: common: add API to get if the platform supports TPL
The TPL (Targeted Peripheral List) is used for targeted hosts
(non-PC hosts), and it can be used at USB OTG & EH certification
and some specific products which need white list.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:28:41 -07:00
Peter Chen
9bd0181c74 usb: core: Kconfig: TPL should apply for both OTG and EH
Update configuration for USB_OTG_WHITELIST, any targeted hosts
(non PC-hosts) can have TPL (Targered Peripheral List).

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:28:41 -07:00
Peter Chen
026f3fcbb0 usb: core: TPL should apply for both OTG and EH
According to On-The-Go and Embedded Host Supplement to the USB Revision
2.0 Specification, the targeted hosts (non-PC hosts) include both
embedded hosts and otg, and each targeted host product defines the
set of supported peripherals on a TPL (Targeted Peripheral List). So,
TPL should apply for both OTG and embedded host, and the otg support is
not a must for embedded host.

The TPL support feature will only be effect when CONFIG_USB_OTG_WHITELIST
has been chosen and hcd->tpl_support flag is set, it can avoid the enumeration
fails problem for the user who chooses CONFIG_USB_OTG_WHITELIST wrongly.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:28:41 -07:00
Peter Chen
f2693b430b usb: hcd: add TPL support flag
The targeted hosts (non-PC hosts) need to have TPL (Targeted Peripheral List)
for USB OTG & EH certification and other vendor specific requirements.

The platform who needs TPL feature should set this flag at usb host
controller driver.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:28:41 -07:00
Peter Hurley
99416322dd tty: Workaround Alpha non-atomic byte storage in tty_struct
The Alpha EV4/EV5 cpus can corrupt adjacent byte and short data because
those cpus use RMW to store byte and short data. Thus, concurrent adjacent
byte stores could become corrupted, if serialized by a different lock.
tty_struct uses different locks to protect certain fields within the
structure, and thus is vulnerable to byte stores which are not atomic.

Merge the ->ctrl_status byte and packet mode bit, both protected by the
->ctrl_lock, into an unsigned long.

The padding bits are necessary to force the compiler to allocate the
type specified; otherwise, gcc will ignore the type specifier and
allocate the minimum number of bytes required to store the bitfield.
In turn, this would allow Alpha EV4/EV5 cpus to corrupt adjacent byte
or short storage (because those cpus use RMW to store byte and short data).

gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields
smaller than unsigned long on ia64, ppc64, hppa64, and sparc64, thus
requiring more than unsigned int storage (which would otherwise be
sufficient to fix the Alpha non-atomic storage problem).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:36 -07:00
Peter Hurley
c274f6ef1c tty: Hold termios_rwsem for tcflow(TCIxxx)
While transmitting a START/STOP char for tcflow(TCION/TCIOFF), prevent
a termios change. Otherwise, a garbage in-band flow control char
may be sent, if the termios change overlaps the transmission setup.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:36 -07:00
Peter Hurley
136d5258b2 tty: Move and rename send_prio_char() as tty_send_xchar()
Relocate the file-scope function, send_prio_char(), as a global
helper tty_send_xchar(). Remove the global declarations for
tty_write_lock()/tty_write_unlock(), as these are file-scope only now.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00
Peter Hurley
c545b66c69 tty: Serialize tcflow() with other tty flow control changes
Use newly-introduced tty->flow_lock to serialize updates to
tty->flow_stopped (via tcflow()) and with concurrent tty flow
control changes from other sources.

Merge the storage for ->stopped and ->flow_stopped, now that both
flags are serialized by ->flow_lock.

The padding bits are necessary to force the compiler to allocate the
type specified; otherwise, gcc will ignore the type specifier and
allocate the minimum number of bytes necessary to store the bitfield.
In turn, this would allow Alpha EV4 and EV5 cpus to corrupt adjacent
byte storage because those cpus use RMW to store byte and short data.

gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields
smaller than unsigned long on ia64, ppc64, hppa64 and sparc64, thus
requiring more than unsigned int storage (which would otherwise be
sufficient to workaround the Alpha non-atomic byte/short storage problem).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00
Peter Hurley
01adc80706 tty: Move packet mode flow control notifications to pty driver
When a master pty is set to packet mode, flow control changes to
the slave pty cause notifications to the master pty via reads and
polls. However, these tests are occurring for all ttys, not
just ptys.

Implement flow control packet mode notifications in the pty driver.
Only the slave side implements the flow control handlers since
packet mode is asymmetric; the master pty receives notifications
for slave-side changes, but not vice versa.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00
Peter Hurley
f9e053dcfc tty: Serialize tty flow control changes with flow_lock
Without serialization, the flow control state can become inverted
wrt. the actual hardware state. For example,

CPU 0                          | CPU 1
stop_tty()                     |
  lock ctrl_lock               |
  tty->stopped = 1             |
  unlock ctrl_lock             |
                               | start_tty()
                               |   lock ctrl_lock
                               |   tty->stopped = 0
                               |   unlock ctrl_lock
                               |   driver->start()
  driver->stop()               |

In this case, the flow control state now indicates the tty has
been started, but the actual hardware state has actually been stopped.

Introduce tty->flow_lock spinlock to serialize tty flow control changes.
Split out unlocked __start_tty()/__stop_tty() flavors for use by
ioctl(TCXONC) in follow-on patch.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00
Peter Hurley
d7a855bd6a tty: Convert tty_struct bitfield to ints
The stopped, hw_stopped, flow_stopped and packet bits are smp-unsafe
and interrupt-unsafe. For example,

CPU 0                         | CPU 1
                              |
tty->flow_stopped = 1         | tty->hw_stopped = 0

One of these updates will be corrupted, as the bitwise operation
on the bitfield is non-atomic.

Ensure each flag has a separate memory location, so concurrent
updates do not corrupt orthogonal states. Because DEC Alpha EV4 and EV5
cpus (from 1995) perform RMW on smaller-than-machine-word storage,
"separate memory location" must be int instead of byte.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00