- 30 Jun, 2014 15 commits
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Andy Lutomirski authored
commit 554086d8 upstream. The bad syscall nr paths are their own incomprehensible route through the entry control flow. Rearrange them to work just like syscalls that return -ENOSYS. This fixes an OOPS in the audit code when fast-path auditing is enabled and sysenter gets a bad syscall nr (CVE-2014-4508). This has probably been broken since Linux 2.6.27: af0575bb i386 syscall audit fast-path Cc: Roland McGrath <roland@redhat.com> Reported-by:
Toralf Förster <toralf.foerster@gmx.de> Signed-off-by:
Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/e09c499eade6fc321266dd6b54da7beb28d6991c.1403558229.git.luto@amacapital.netSigned-off-by:
H. Peter Anvin <hpa@linux.intel.com> Signed-off-by:
Luis Henriques <luis.henriques@canonical.com>
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Greg Kroah-Hartman authored
commit 206a81c1 upstream. The lzo decompressor can, if given some really crazy data, possibly overrun some variable types. Modify the checking logic to properly detect overruns before they happen. Reported-by:
"Don A. Bailey" <donb@securitymouse.com> Tested-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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Mathias Krause authored
commit 278f2b3e upstream. The ulog messages leak heap bytes by the means of padding bytes and incompletely filled string arrays. Fix those by memset(0)'ing the whole struct before filling it. Signed-off-by:
Mathias Krause <minipli@googlemail.com> Signed-off-by:
Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jan Tore Morken <jantore@morken.priv.no> Signed-off-by:
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Benjamin LaHaise authored
commit edfbbf38 upstream. A kernel memory disclosure was introduced in aio_read_events_ring() in v3.10 by commit a31ad380. The changes made to aio_read_events_ring() failed to correctly limit the index into ctx->ring_pages[], allowing an attacked to cause the subsequent kmap() of an arbitrary page with a copy_to_user() to copy the contents into userspace. This vulnerability has been assigned CVE-2014-0206. Thanks to Mateusz and Petr for disclosing this issue. This patch applies to v3.12+. A separate backport is needed for 3.10/3.11. [jmoyer@redhat.com: backported to 3.10] Signed-off-by:
Benjamin LaHaise <bcrl@kvack.org> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Petr Matousek <pmatouse@redhat.com> Cc: Kent Overstreet <kmo@daterainc.com> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by:
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Benjamin LaHaise authored
commit f8567a38 upstream. The aio cleanups and optimizations by kmo that were merged into the 3.10 tree added a regression for userspace event reaping. Specifically, the reference counts are not decremented if the event is reaped in userspace, leading to the application being unable to submit further aio requests. This patch applies to 3.12+. A separate backport is required for 3.10/3.11. This issue was uncovered as part of CVE-2014-0206. [jmoyer@redhat.com: backported to 3.10] Signed-off-by:
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Jianguo Wu authored
commit 86f40622 upstream. When enable LPAE and big-endian in a hisilicon board, while specify mem=384M mem=512M@7680M, will get bad page state: Freeing unused kernel memory: 180K (c0466000 - c0493000) BUG: Bad page state in process init pfn:fa442 page:c7749840 count:0 mapcount:-1 mapping: (null) index:0x0 page flags: 0x40000400(reserved) Modules linked in: CPU: 0 PID: 1 Comm: init Not tainted 3.10.27+ #66 [<c000f5f0>] (unwind_backtrace+0x0/0x11c) from [<c000cbc4>] (show_stack+0x1n0/0x14) [<c000cbc4>] (show_stack+0x10/0x14) from [<c009e448>] (bad_page+0xd4/0x104) [<c009e448>] (bad_page+0xd4/0x104) from [<c009e520>] (free_pages_prepare+0xa8/0x14c) [<c009e520>] (free_pages_prepare+0xa8/0x14c) from [<c009f8ec>] (free_hot_cold_page+0x18/0xf0) [<c009f8ec>] (free_hot_cold_page+0x18/0xf0) from [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) from [<c00b6458>] (handle_mm_fault+0xf4/0x120) [<c00b6458>] (handle_mm_fault+0xf4/0x120) from [<c0013754>] (do_page_fault+0xfc/0x354) [<c0013754>] (do_page_fault+0xfc/0x354) from [<c0008400>] (do_DataAbort+0x2c/0x90) [<c0008400>] (do_DataAbort+0x2c/0x90) from [<c0008fb4>] (__dabt_usr+0x34/0x40) The bad pfn:fa442 is not system memory(mem=384M mem=512M@7680M), after debugging, I find in page fault handler, will get wrong pfn from pte just after set pte, as follow: do_anonymous_page() { ... set_pte_at(mm, address, page_table, entry); //debug code pfn = pte_pfn(entry); pr_info("pfn:0x%lx, pte:0x%llxn", pfn, pte_val(entry)); //read out the pte just set new_pte = pte_offset_map(pmd, address); new_pfn = pte_pfn(*new_pte); pr_info("new pfn:0x%lx, new pte:0x%llxn", pfn, pte_val(entry)); ... } pfn: 0x1fa4f5, pte:0xc00001fa4f575f new_pfn:0xfa4f5, new_pte:0xc00000fa4f5f5f //new pfn/pte is wrong. The bug is happened in cpu_v7_set_pte_ext(ptep, pte): An LPAE PTE is a 64bit quantity, passed to cpu_v7_set_pte_ext in the r2 and r3 registers. On an LE kernel, r2 contains the LSB of the PTE, and r3 the MSB. On a BE kernel, the assignment is reversed. Unfortunately, the current code always assumes the LE case, leading to corruption of the PTE when clearing/setting bits. This patch fixes this issue much like it has been done already in the cpu_v7_switch_mm case. Signed-off-by:
Jianguo Wu <wujianguo@huawei.com> Acked-by:
Marc Zyngier <marc.zyngier@arm.com> Acked-by:
Will Deacon <will.deacon@arm.com> Signed-off-by:
Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by:
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Johan Hovold authored
commit c14829fa upstream. Only call usb_autopm_put_interface() if the corresponding usb_autopm_get_interface() was successful. This prevents a potential runtime PM counter imbalance should usb_autopm_get_interface() fail. Note that the USB PM usage counter is reset when the interface is unbound, but that the runtime PM counter may be left unbalanced. Also add comment on why we don't need to worry about racing resume/suspend on autopm_get failures. Fixes: d5fd650c ("usb: serial: prevent suspend/resume from racing against probe/remove") Signed-off-by:
Johan Hovold <jhovold@gmail.com> Signed-off-by:
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Aleksander Morgado authored
commit 0ce5fb58 upstream. A set of new VID/PIDs retrieved from the out-of-tree GobiNet/GobiSerial Sierra Wireless drivers. Signed-off-by:
Aleksander Morgado <aleksander@aleksander.es> Link: http://marc.info/?l=linux-usb&m=140136310027293&w=2Signed-off-by:
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Aleksander Morgado authored
commit ff1fcd50 upstream. Signed-off-by:
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Johan Hovold authored
commit 79eed03e upstream. The delayed-write queue was never emptied at shutdown (close), something which could lead to leaked urbs if the port is closed before being runtime resumed due to a write. When this happens the output buffer would not drain on close (closing_wait timeout), and after consecutive opens, writes could be corrupted with previously buffered data, transfered with reduced throughput or completely blocked. Note that unbusy_queued_urb() was simply moved out of CONFIG_PM. Fixes: 383cedc3 ("USB: serial: full autosuspend support for the option driver") Signed-off-by:
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Paul Bolle authored
commit 77c2f02e upstream. Commit 193ab2a6 ("usb: gadget: allow multiple gadgets to be built") apparently required that checks for CONFIG_USB_GADGET_OMAP would be replaced with checks for CONFIG_USB_OMAP. Do so now for the remaining checks for CONFIG_USB_GADGET_OMAP, even though these checks have basically been broken since v3.1. And, since we're touching this code, use the IS_ENABLED() macro, so things will now (hopefully) also work if USB_OMAP is modular. Fixes: 193ab2a6 ("usb: gadget: allow multiple gadgets to be built") Signed-off-by:
Paul Bolle <pebolle@tiscali.nl> Signed-off-by:
Tony Lindgren <tony@atomide.com> Signed-off-by:
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Paul Bolle authored
commit d30f2065 upstream. Commit 193ab2a6 ("usb: gadget: allow multiple gadgets to be built") basically renamed the Kconfig symbol USB_GADGET_PXA25X to USB_PXA25X. It did not rename the related macros in use at that time. Commit c0a39151 ("ARM: pxa: fix inconsistent CONFIG_USB_PXA27X") did so for all but one macro. Rename that last macro too now. Fixes: 193ab2a6 ("usb: gadget: allow multiple gadgets to be built") Signed-off-by:
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Dan Carpenter authored
commit 8bab797c upstream. This is a static checker fix. The "dev" variable is always NULL after the while statement so we would be dereferencing a NULL pointer here. Fixes: 819a3eba ('[PATCH] applicom: fix error handling') Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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Paul Bolle authored
commit d3921a03 upstream. Commit d0f47ff1 ("ASoC: OMAP: Build config cleanup for McBSP") removed the Kconfig symbol OMAP_MCBSP. It left two checks for CONFIG_OMAP_MCBSP untouched. Convert these to checks for CONFIG_SND_OMAP_SOC_MCBSP. That must be correct, since that re-enables calls to functions that are all found in sound/soc/omap/mcbsp.c. And that file is built only if CONFIG_SND_OMAP_SOC_MCBSP is defined. Fixes: d0f47ff1 ("ASoC: OMAP: Build config cleanup for McBSP") Signed-off-by:
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Nicholas Bellinger authored
This patch changes rd_allocate_sgl_table() to explicitly clear ramdisk_mcp backend memory pages by passing __GFP_ZERO into alloc_pages(). This addresses a potential security issue where reading from a ramdisk_mcp could return sensitive information, and follows what >= v3.15 does to explicitly clear ramdisk_mcp memory at backend device initialization time. [ Note that a different patch to address the same issue went in during v3.15-rc1 (commit 4442dc8a), but includes a bunch of other changes that don't strictly apply to fixing the bug. This is a one-liner that addresses the bug for all <= v3.14 versions. ] Reported-by:
Jorge Daniel Sequeira Matias <jdsm@tecnico.ulisboa.pt> Cc: Jorge Daniel Sequeira Matias <jdsm@tecnico.ulisboa.pt> Signed-off-by:
Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by:
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- 27 Jun, 2014 25 commits
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Lars-Peter Clausen authored
commit 883a1d49 upstream. The ALSA control code expects that the range of assigned indices to a control is continuous and does not overflow. Currently there are no checks to enforce this. If a control with a overflowing index range is created that control becomes effectively inaccessible and unremovable since snd_ctl_find_id() will not be able to find it. This patch adds a check that makes sure that controls with a overflowing index range can not be created. Signed-off-by:
Lars-Peter Clausen <lars@metafoo.de> Acked-by:
Jaroslav Kysela <perex@perex.cz> Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
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Lars-Peter Clausen authored
commit ac902c11 upstream. Each control gets automatically assigned its numids when the control is created. The allocation is done by incrementing the numid by the amount of allocated numids per allocation. This means that excessive creation and destruction of controls (e.g. via SNDRV_CTL_IOCTL_ELEM_ADD/REMOVE) can cause the id to eventually overflow. Currently when this happens for the control that caused the overflow kctl->id.numid + kctl->count will also over flow causing it to be smaller than kctl->id.numid. Most of the code assumes that this is something that can not happen, so we need to make sure that it won't happen Signed-off-by:
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Lars-Peter Clausen authored
commit fd9f26e4 upstream. A control that is visible on the card->controls list can be freed at any time. This means we must not access any of its memory while not holding the controls_rw_lock. Otherwise we risk a use after free access. Signed-off-by:
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Lars-Peter Clausen authored
commit 82262a46 upstream. There are two issues with the current implementation for replacing user controls. The first is that the code does not check if the control is actually a user control and neither does it check if the control is owned by the process that tries to remove it. That allows userspace applications to remove arbitrary controls, which can cause a user after free if a for example a driver does not expect a control to be removed from under its feed. The second issue is that on one hand when a control is replaced the user_ctl_count limit is not checked and on the other hand the user_ctl_count is increased (even though the number of user controls does not change). This allows userspace, once the user_ctl_count limit as been reached, to repeatedly replace a control until user_ctl_count overflows. Once that happens new controls can be added effectively bypassing the user_ctl_count limit. Both issues can be fixed by instead of open-coding the removal of the control that is to be replaced to use snd_ctl_remove_user_ctl(). This function does proper permission checks as well as decrements user_ctl_count after the control has been removed. Note that by using snd_ctl_remove_user_ctl() the check which returns -EBUSY at beginning of the function if the control already exists is removed. This is not a problem though since the check is quite useless, because the lock that is protecting the control list is released between the check and before adding the new control to the list, which means that it is possible that a different control with the same settings is added to the list after the check. Luckily there is another check that is done while holding the lock in snd_ctl_add(), so we'll rely on that to make sure that the same control is not added twice. Signed-off-by:
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Lars-Peter Clausen authored
commit 07f4d9d7 upstream. The user-control put and get handlers as well as the tlv do not protect against concurrent access from multiple threads. Since the state of the control is not updated atomically it is possible that either two write operations or a write and a read operation race against each other. Both can lead to arbitrary memory disclosure. This patch introduces a new lock that protects user-controls from concurrent access. Since applications typically access controls sequentially than in parallel a single lock per card should be fine. Signed-off-by:
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Suravee Suthikulpanit authored
commit f3a183cb upstream. Arm64 does not define dma_get_required_mask() function. Therefore, it should not define the ARCH_HAS_DMA_GET_REQUIRED_MASK. This causes build errors in some device drivers (e.g. mpt2sas) Signed-off-by:
Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com> [ luis: backported to 3.11: adjusted context ] Signed-off-by:
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Will Deacon authored
commit c1688707 upstream. Our compat PTRACE_POKEUSR implementation simply passes the user data to regset_copy_from_user after some simple range checking. Unfortunately, the data in question has already been copied to the kernel stack by this point, so the subsequent access_ok check fails and the ptrace request returns -EFAULT. This causes problems tracing fork() with older versions of strace. This patch briefly changes the fs to KERNEL_DS, so that the access_ok check passes even with a kernel address. Signed-off-by:
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Alan Stern authored
commit 32b36eea upstream. In usbtest, tests 5 - 8 use the scatter-gather library in usbcore without any sort of timeout. If there's a problem in the gadget or host controller being tested, the test can hang. This patch adds a 10-second timeout to the tests, so that they will fail gracefully with an ETIMEDOUT error instead of hanging. Signed-off-by:
Alan Stern <stern@rowland.harvard.edu> Reported-by:
Huang Rui <ray.huang@amd.com> Tested-by:
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Roger Quadros authored
commit e5e47465 upstream. Without a timetout some tests e.g. test_halt() can remain stuck forever. Signed-off-by:
Roger Quadros <rogerq@ti.com> Reviewed-by:
Felipe Balbi <balbi@ti.com> Signed-off-by:
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Alan Stern authored
commit b0a50e92 upstream. Leandro Liptak reports that his HASEE E200 computer hangs when we ask the BIOS to hand over control of the EHCI host controller. This definitely sounds like a bug in the BIOS, but at the moment there is no way to fix it. This patch works around the problem by avoiding the handoff whenever the motherboard and BIOS version match those of Leandro's computer. Signed-off-by:
Leandro Liptak <leandroliptak@gmail.com> Tested-by:
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Rafael J. Wysocki authored
commit 12e27b11 upstream. Commit 66345d5f (ACPI / ia64 / sba_iommu: Use ACPI scan handler for device discovery) changed the ordering of SBA (System Bus Adapter) IOMMU initialization with respect to the PCI host bridge initialization which broke things inadvertently, because the SBA IOMMU initialization code has to run after the PCI host bridge has been initialized. Fix that by reworking the SBA IOMMU ACPI scan handler so that it claims the discovered matching ACPI device objects without attempting to initialize anything and move the entire SBA IOMMU initialization to sba_init() that runs after the PCI bus has been enumerated. Link: https://bugzilla.kernel.org/show_bug.cgi?id=76691 Fixes: 66345d5f (ACPI / ia64 / sba_iommu: Use ACPI scan handler for device discovery) Reported-and-tested-by:
Émeric Maschino <emeric.maschino@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by:
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Jiang Liu authored
commit f3ffaaa8 upstream. To: linux-kernel@vger.kernel.org Fix the section mismatch warning by remove __init annotate for functions ioc_iova_init(), ioc_init() and acpi_sba_ioc_add() because they may be called at runtime. WARNING: vmlinux.o(.data+0x66ee0): Section mismatch in reference from the variable acpi_sba_ioc_handler to the function .init.text:acpi_sba_ioc_add() The variable acpi_sba_ioc_handler references the function __init acpi_sba_ioc_add() Signed-off-by:
Jiang Liu <jiang.liu@linux.intel.com> Signed-off-by:
Tony Luck <tony.luck@intel.com> Signed-off-by:
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Dan Carpenter authored
commit 4f3bcd87 upstream. at91_adc_get_trigger_value_by_name() was returning -ENOMEM truncated to a positive u8 and that doesn't work. I've changed it to int and refactored it to preserve the error code. Signed-off-by:
Alexandre Belloni <alexandre.belloni@free-electrons.com> Tested-by:
Jonathan Cameron <jic23@kernel.org> Signed-off-by:
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Thomas Gleixner authored
commit 3d5c9340 upstream. Even in the case when deadlock detection is not requested by the caller, we can detect deadlocks. Right now the code stops the lock chain walk and keeps the waiter enqueued, even on itself. Silly not to yell when such a scenario is detected and to keep the waiter enqueued. Return -EDEADLK unconditionally and handle it at the call sites. The futex calls return -EDEADLK. The non futex ones dequeue the waiter, throw a warning and put the task into a schedule loop. Tagged for stable as it makes the code more robust. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Brad Mouring <bmouring@ni.com> Link: http://lkml.kernel.org/r/20140605152801.836501969@linutronix.deSigned-off-by:
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Peter Meerwald authored
commit 8ba42fb7 upstream. i2c_smbus_read_word_data() does host endian conversion already, no need for le16_to_cpu() Signed-off-by:
Peter Meerwald <pmeerw@pmeerw.net> Signed-off-by:
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Paul Kocialkowski authored
commit e0326be0 upstream. Not setting the raw parameter in the request causes it to be randomly initialized to a value that might be different from zero or zero. This leads to values that are randomly either raw or processed, making it very difficult to make reliable use of the values. Signed-off-by:
Paul Kocialkowski <contact@paulk.fr> Acked-by:
Sebastian Reichel <sre@kernel.org> Signed-off-by:
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Mario Schuknecht authored
commit c404618c upstream. Consider high byte of proximity min and max treshold in function 'tsl2x7x_chip_on'. So far, the high byte was not set. Signed-off-by:
Mario Schuknecht <mario.schuknecht@dresearch-fe.de> Signed-off-by:
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Johan Hovold authored
commit 5292afa6 upstream. Make sure only to decrement the PM counters if they were actually incremented. Note that the USB PM counter, but not necessarily the driver core PM counter, is reset when the interface is unbound. Fixes: 11ea859d ("USB: additional power savings for cdc-acm devices that support remote wakeup") Signed-off-by:
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Johan Hovold authored
commit e4c36076 upstream. Make sure to kill any already submitted read urbs on read-urb submission failures in open in order to prevent doing I/O for a closed port. Fixes: 088c64f8 ("USB: cdc-acm: re-write read processing") Signed-off-by:
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Till Dörges authored
commit a24bc323 upstream. I've got the following DAB USB stick that also works fine with the DVB_USB_RTL28XXU driver after I added its USB ID: Bus 001 Device 009: ID 0ccd:00b4 TerraTec Electronic GmbH [crope@iki.fi: apply patch partly manually] Signed-off-by:
Till Dörges <till@doerges.net> Signed-off-by:
Antti Palosaari <crope@iki.fi> Signed-off-by:
Mauro Carvalho Chehab <m.chehab@samsung.com> Signed-off-by:
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Robert Backhaus authored
commit d22d32e1 upstream. GIT_AUTHOR_DATE=1386943312 Add USB IDs for the WinFast DTV Dongle Mini. Device is tested and works fine under MythTV Signed-off-by:
Robert Backhaus <robbak@robbak.com> Acked-by:
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Scott Wood authored
commit 6663a4fa upstream. Commit 59a53afe "powerpc: Don't setup CPUs with bad status" broke ePAPR SMP booting. ePAPR says that CPUs that aren't presently running shall have status of disabled, with enable-method being used to determine whether the CPU can be enabled. Fix by checking for spin-table, which is currently the only supported enable-method. Signed-off-by:
Scott Wood <scottwood@freescale.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Emil Medve <Emilian.Medve@Freescale.com> Signed-off-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
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James Hogan authored
commit 6979f8d2 upstream. Commit c49436b6 (serial: 8250_dw: Improve unwritable LCR workaround) caused a regression. It added a check that the LCR was written properly to detect and workaround the busy quirk, but the behaviour of bit 5 (UART_LCR_SPAR) differs between IP versions 3.00a and 3.14c per the docs. On older versions this caused the check to fail and it would repeatedly force idle and rewrite the LCR register, causing delays and preventing any input from serial being received. This is fixed by masking out UART_LCR_SPAR before making the comparison. Signed-off-by:
James Hogan <james.hogan@imgtec.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Tim Kryger <tim.kryger@linaro.org> Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com> Cc: Matt Porter <matt.porter@linaro.org> Cc: Markus Mayer <markus.mayer@linaro.org> Tested-by:
Tim Kryger <tim.kryger@linaro.org> Tested-by:
Ezequiel Garcia <ezequiel.garcia@free-electrons.com> Tested-by:
Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by:
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Tim Kryger authored
commit c49436b6 upstream. When configured with UART_16550_COMPATIBLE=NO or in versions prior to the introduction of this option, the Designware UART will ignore writes to the LCR if the UART is busy. The current workaround saves a copy of the last written LCR and re-writes it in the ISR for a special interrupt that is raised when a write was ignored. Unfortunately, interrupts are typically disabled prior to performing a sequence of register writes that include the LCR so the point at which the retry occurs is too late. An example is serial8250_do_set_termios() where an ignored LCR write results in the baud divisor not being set and instead a garbage character is sent out the transmitter. Furthermore, since serial_port_out() offers no way to indicate failure, a serious effort must be made to ensure that the LCR is actually updated before returning back to the caller. This is difficult, however, as a UART that was busy during the first attempt is likely to still be busy when a subsequent attempt is made unless some extra action is taken. This updated workaround reads back the LCR after each write to confirm that the new value was accepted by the hardware. Should the hardware ignore a write, the TX/RX FIFOs are cleared and the receive buffer read before attempting to rewrite the LCR out of the hope that doing so will force the UART into an idle state. While this may seem unnecessarily aggressive, writes to the LCR are used to change the baud rate, parity, stop bit, or data length so the data that may be lost is likely not important. Admittedly, this is far from ideal but it seems to be the best that can be done given the hardware limitations. Lastly, the revised workaround doesn't touch the LCR in the ISR, so it avoids the possibility of a "serial8250: too much work for irq" lock up. This problem is rare in real situations but can be reproduced easily by wiring up two UARTs and running the following commands. # stty -F /dev/ttyS1 echo # stty -F /dev/ttyS2 echo # cat /dev/ttyS1 & [1] 375 # echo asdf > /dev/ttyS1 asdf [ 27.700000] serial8250: too much work for irq96 [ 27.700000] serial8250: too much work for irq96 [ 27.710000] serial8250: too much work for irq96 [ 27.710000] serial8250: too much work for irq96 [ 27.720000] serial8250: too much work for irq96 [ 27.720000] serial8250: too much work for irq96 [ 27.730000] serial8250: too much work for irq96 [ 27.730000] serial8250: too much work for irq96 [ 27.740000] serial8250: too much work for irq96 Signed-off-by:
Matt Porter <matt.porter@linaro.org> Reviewed-by:
Markus Mayer <markus.mayer@linaro.org> Reviewed-by:
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Tim Kryger authored
commit 33acbb82 upstream. When a serial port is configured for RTS/CTS flow control, serial core will disable the transmitter if it observes CTS is de-asserted. This is perfectly reasonable and appropriate when the UART lacks the ability to automatically perform CTS flow control. However, if the UART hardware can manage flow control automatically, it is important that software not get involved. When the DesignWare UART enables 16C750 style auto-RTS/CTS it stops generating interrupts for changes in CTS state so software mostly stays out of the way. However, it does report the true state of CTS in the MSR so software may notice it is de-asserted and respond by improperly disabling the transmitter. Once this happens the transmitter will be blocked forever. To avoid this situation, we simply lie to the 8250 and serial core by reporting that CTS is asserted whenever auto-RTS/CTS mode is enabled. Signed-off-by:
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