Drivers/subsystems creating scatterlists for DMA should be taking care
to respect the scatter-gather limitations of the appropriate device, as
described by dma_parms. A DMA API implementation cannot feasibly split
a scatterlist into *more* entries than originally passed, so it is not
well defined what they should do when given a segment larger than the
limit they are also required to respect.
Conversely, devices which are less limited than the rather conservative
defaults, or indeed have no limitations at all (e.g. GPUs with their own
internal MMU), should be encouraged to set appropriate dma_parms, as
they may get more efficient DMA mapping performance out of it.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Only used by the AMD GART and Intel VT-D drivers, which must be built in.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Just keep a single variable with a descriptive name instead of two
with confusing names.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Most mainstream architectures are using 65536 entries, so lets stick to
that. If someone is really desperate to override it that can still be
done through <asm/dma-mapping.h>, but I'd rather see a really good
rationale for that.
dma_debug_init is now called as a core_initcall, which for many
architectures means much earlier, and provides dma-debug functionality
earlier in the boot process. This should be safe as it only relies
on the memory allocator already being available.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Marty reported a memory leakage introduced by commit 3aaabbf1c3
("lib/dma-debug.c: fix incorrect pfn calculation"). Fix it
by checking the virtual address before allocating the entry.
This patch also use virt_addr_valid() instead of virt_to_page()
to check if a virtual address is linear.
Fixes: 3aaabbf1 ("lib/dma-debug.c: fix incorrect pfn calculation")
Reported-by: Marty Faltesek <mfaltesek@google.com>
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
dma-debug reports the following warning:
WARNING: CPU: 3 PID: 298 at kernel-4.4/lib/dma-debug.c:604
debug _dma_assert_idle+0x1a8/0x230()
DMA-API: cpu touching an active dma mapped cacheline [cln=0x00000882300]
CPU: 3 PID: 298 Comm: vold Tainted: G W O 4.4.22+ #1
Hardware name: MT6739 (DT)
Call trace:
debug_dma_assert_idle+0x1a8/0x230
wp_page_copy.isra.96+0x118/0x520
do_wp_page+0x4fc/0x534
handle_mm_fault+0xd4c/0x1310
do_page_fault+0x1c8/0x394
do_mem_abort+0x50/0xec
I found that debug_dma_alloc_coherent() and debug_dma_free_coherent()
assume that dma_alloc_coherent() always returns a linear address.
However it's possible that dma_alloc_coherent() returns a non-linear
address. In this case, page_to_pfn(virt_to_page(virt)) will return an
incorrect pfn. If the pfn is valid and mapped as a COW page, we will
hit the warning when doing wp_page_copy().
Fix this by calculating pfn for linear and non-linear addresses.
[miles.chen@mediatek.com: v4]
Link: http://lkml.kernel.org/r/1510872972-23919-1-git-send-email-miles.chen@mediatek.com
Link: http://lkml.kernel.org/r/1506484087-1177-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This time again a smaller update consisting of:
- support for TI DA8xx dma controller and updates to the cppi driver
- updates on bunch of drivers like xilinx, pl08x, stm32-dma, mv_xor, ioat,
dmatest
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=Ygkn
-----END PGP SIGNATURE-----
Merge tag 'dmaengine-4.12-rc1' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine updates from Vinod Koul:
"This time again a smaller update consisting of:
- support for TI DA8xx dma controller and updates to the cppi driver
- updates on bunch of drivers like xilinx, pl08x, stm32-dma, mv_xor,
ioat, dmatest"
* tag 'dmaengine-4.12-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (35 commits)
dmaengine: pl08x: remove lock documentation
dmaengine: pl08x: fix pl08x_dma_chan_state documentation
dmaengine: pl08x: Use the BIT() macro consistently
dmaengine: pl080: Fix some missing kerneldoc
dmaengine: pl080: Cut some unused defines
dmaengine: dmatest: Add check for supported buffer count (sg_buffers)
dmaengine: dmatest: Select DMA_ENGINE_RAID as its needed for the slave_sg test
dmaengine: virt-dma: Convert to use list_for_each_entry_safe()
dma-debug: use offset_in_page() macro
dmaengine: mv_xor: use offset_in_page() macro
dmaengine: dmatest: use offset_in_page() macro
dmaengine: sun4i: fix invalid argument
dmaengine: ioat: use setup_timer
dmaengine: cppi41: Fix an Oops happening in cppi41_dma_probe()
dmaengine: pl330: remove pdata based initialization
dmaengine: cppi: fix build error due to bad variable
dmaengine: imx-sdma: add 1ms delay to ensure SDMA channel is stopped
dmaengine: cppi41: use managed functions devm_*()
dmaengine: cppi41: fix cppi41_dma_tx_status() logic
dmaengine: qcom_hidma: pause the channel on shutdown
...
Interrupt enable/disabled with spinlock is not a valid operation for RT
as it can make executing tasks sleep from a non-sleepable context. So
convert it to spin_lock_irq[save, restore].
Link: http://lkml.kernel.org/r/1492065666-3816-1-git-send-email-pagupta@redhat.com
Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ville Syrjl <ville.syrjala@linux.intel.com>
Cc: Miles Chen <miles.chen@mediatek.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add comment for failure to check a map error to help driver developers.
Link: http://lkml.kernel.org/r/1484622289-22085-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is bit large pile of code which bring in some nice additions:
- Error reporting: we have added a new mechanism for users of dmaenegine to
register a callback_result which tells them the result of the dma
transaction. Right now only one user ntb is using it.
- As we discussed on KS mailing list and pointed out NO_IRQ has no place in
kernel, this also remove NO_IRQ from dmaengine subsystem (both arm and
ppc users)
- Support for IOMMU slave transfers and it implementation for arm.
- To get better build coverage, enable COMPILE_TEST for bunch of driver,
and fix the warning and sparse complaints on these.
- Apart from above, usual updates spread across drivers.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=9iA3
-----END PGP SIGNATURE-----
Merge tag 'dmaengine-4.9-rc1' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine updates from Vinod Koul:
"This is bit large pile of code which bring in some nice additions:
- Error reporting: we have added a new mechanism for users of
dmaenegine to register a callback_result which tells them the
result of the dma transaction. Right now only one user (ntb) is
using it.
- As we discussed on KS mailing list and pointed out NO_IRQ has no
place in kernel, this also remove NO_IRQ from dmaengine subsystem
(both arm and ppc users)
- Support for IOMMU slave transfers and its implementation for arm.
- To get better build coverage, enable COMPILE_TEST for bunch of
driver, and fix the warning and sparse complaints on these.
- Apart from above, usual updates spread across drivers"
* tag 'dmaengine-4.9-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (169 commits)
async_pq_val: fix DMA memory leak
dmaengine: virt-dma: move function declarations
dmaengine: omap-dma: Enable burst and data pack for SG
DT: dmaengine: rcar-dmac: document R8A7743/5 support
dmaengine: fsldma: Unmap region obtained by of_iomap
dmaengine: jz4780: fix resource leaks on error exit return
dma-debug: fix ia64 build, use PHYS_PFN
dmaengine: coh901318: fix integer overflow when shifting more than 32 places
dmaengine: edma: avoid uninitialized variable use
dma-mapping: fix m32r build warning
dma-mapping: fix ia64 build, use PHYS_PFN
dmaengine: ti-dma-crossbar: enable COMPILE_TEST
dmaengine: omap-dma: enable COMPILE_TEST
dmaengine: edma: enable COMPILE_TEST
dmaengine: ti-dma-crossbar: Fix of_device_id data parameter usage
dmaengine: ti-dma-crossbar: Correct type for of_find_property() third parameter
dmaengine/ARM: omap-dma: Fix the DMAengine compile test on non OMAP configs
dmaengine: edma: Rename set_bits and remove unused clear_bits helper
dmaengine: edma: Use correct type for of_find_property() third parameter
dmaengine: edma: Fix of_device_id data parameter usage (legacy vs TPCC)
...
kbuild test robot reports:
lib/dma-debug.c: In function 'debug_dma_map_resource':
>> lib/dma-debug.c:1541:16: error: implicit declaration of function '__phys_to_pfn' [-Werror=implicit-function-declaration]
entry->pfn = __phys_to_pfn(addr);
^~~~~~~~~~~~~
ia64 does not provide __phys_to_pfn(), use the PHYS_PFN() alias.
Fixes: 0e74b34dfc ("dma-debug: add support for resource mappings")
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
A MMIO mapped resource can not be represented by a struct page so a new
debug type is needed to handle this. This patch add such type and
functionality to add/remove entries and how to translate them to a
physical address.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
If we're using CONFIG_VMAP_STACK=y and we manage to point an sg entry
at the stack, then either the sg page will be in highmem or sg_virt()
will return the direct-map alias. In neither case will the existing
check_for_stack() implementation realize that it's a stack page.
Fix it by explicitly checking for stack pages.
This has no effect by itself. It's broken out for ease of review.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/448460622731312298bf19dcbacb1606e75de7a9.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
get_hash_bucket() and put_hash_bucket() acquire and release the same
spinlock, but this confuses static checkers such as sparse
lib/dma-debug.c:254:27: warning: context imbalance in 'get_hash_bucket' - wrong count at exit
lib/dma-debug.c:268:13: warning: context imbalance in 'put_hash_bucket' - unexpected unlock
Add the appropriate acquire and release statements so that checkers can
properly track the lock state.
Link: http://lkml.kernel.org/r/20160701191552.24295-1-sboyd@codeaurora.org
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With netconsole (at least) the pr_err("... disablingn") call can
recurse back into the dma-debug code, where it'll try to grab
free_entries_lock again. Avoid the problem by doing the printk after
dropping the lock.
Link: http://lkml.kernel.org/r/1463678421-18683-1-git-send-email-ville.syrjala@linux.intel.com
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In include/asm-generic/sections.h:
/*
* Usage guidelines:
* _text, _data: architecture specific, don't use them in
* arch-independent code
* [_stext, _etext]: contains .text.* sections, may also contain
* .rodata.*
* and/or .init.* sections
_text is not guaranteed across architectures. Architectures such as ARM
may reuse parts which are not actually text and erroneously trigger a bug.
Switch to using _stext which is guaranteed to contain text sections.
Came out of https://lkml.kernel.org/g/<567B1176.4000106@redhat.com>
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma-debug uses struct dma_debug_entry to keep track of dma coherent
memory allocation requests. The virtual address is converted into a pfn
and an offset. Previously, the offset was calculated using an incorrect
bit mask. As a result, we saw incorrect error messages from dma-debug
like the following:
"DMA-API: exceeded 7 overlapping mappings of cacheline 0x03e00000"
Cacheline 0x03e00000 does not exist on our platform.
Cc: <stable@vger.kernel.org>
Fixes: 0abdd7a81b ("dma-debug: introduce debug_dma_assert_idle()")
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Like dma_unmap_sg, dma_sync_sg* should be called with the original number
of entries passed to dma_map_sg, so do the same check in the sync path as
we do in the unmap path.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sakari Ailus <sakari.ailus@iki.fi>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Its a bit odd that debugfs_create_bool() takes 'u32 *' as an argument,
when all it needs is a boolean pointer.
It would be better to update this API to make it accept 'bool *'
instead, as that will make it more consistent and often more convenient.
Over that bool takes just a byte.
That required updates to all user sites as well, in the same commit
updating the API. regmap core was also using
debugfs_{read|write}_file_bool(), directly and variable types were
updated for that to be bool as well.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If dma-debug is disabled due to a memory error, DMA unmaps do not affect
the dma_active_cacheline radix tree anymore, and debug_dma_assert_idle()
can print false warnings.
Disable debug_dma_assert_idle() when dma_debug_disabled() is true.
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Fixes: 0abdd7a81b ("dma-debug: introduce debug_dma_assert_idle()")
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Horia Geanta <horia.geanta@freescale.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
bucket_find_contain() will search the bucket list for a dma_debug_entry.
When the entry isn't found it needs to search other buckets too, since
only the start address of a dma range is hashed (which might be in a
different bucket).
A copy of the dma_debug_entry is used to get the previous hash bucket
but when its list is searched the original dma_debug_entry is to be used
not its modified copy.
This fixes false "device driver tries to sync DMA memory it has not allocated"
warnings.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Horia Geanta <horia.geanta@freescale.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma_debug_init() is called by architecture specific code at different
levels, but typically as a fs_initcall due to the debugfs initialization.
Some platforms may have early callers of the DMA-API, running prior to the
fs_initcall() level, which is not much of an issue unless
CONFIG_DMA_API_DEBUG is set. When the DMA-API debugging facilities are
turned on a caller will go through:
debug_dma_map_{single,page}
-> dma_mapping_error (inline function usually)
-> debug_dma_mapping_error
-> get_hash_bucket
Calling get_hash_bucket() returns a valid hash value since we hash on high
bits of the dma_addr cookie, but we will grab an unitialized spinlock,
which typically won't crash but produce a warning, the real crash will
however happen during the bucket list traversal because the list has not
been initialized yet.
An obvious solution is of course to move some of the offenders to run
after the fs_initcall level, but since this might not always be an option,
we add a flag "dma_debug_initialized" which is set to false by default,
and set to true once dma_debug_init() has had a chance to run.
The dma_debug_disabled() helper function previously introduced just needs
to check for dma_debug_initialized to allow the caller to proceed or not.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Horia Geanta <horia.geanta@freescale.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a helper function which returns whether the DMA debugging API is
disabled, right now we only check for global_disable, but in order to
accommodate early callers of the DMA-API, we will check for more
initialization flags in the next patch.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Horia Geanta <horia.geanta@freescale.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While debug_dma_assert_idle() checks if a given *page* is actively
undergoing dma the valid granularity of a dma mapping is a *cacheline*.
Sander's testing shows that the warning message "DMA-API: exceeded 7
overlapping mappings of pfn..." is falsely triggering. The test is
simply mapping multiple cachelines in a given page.
Ultimately we want overlap tracking to be valid as it is a real api
violation, so we need to track active mappings by cachelines. Update
the active dma tracking to use the page-frame-relative cacheline of the
mapping as the key, and update debug_dma_assert_idle() to check for all
possible mapped cachelines for a given page.
However, the need to track active mappings is only relevant when the
dma-mapping is writable by the device. In fact it is fairly standard
for read-only mappings to have hundreds or thousands of overlapping
mappings at once. Limiting the overlap tracking to writable
(!DMA_TO_DEVICE) eliminates this class of false-positive overlap
reports.
Note, the radix gang lookup is sub-optimal. It would be best if it
stopped fetching entries once the search passed a page boundary.
Nevertheless, this implementation does not perturb the original net_dma
failing case. That is to say the extra overhead does not show up in
terms of making the failing case pass due to a timing change.
References:
http://marc.info/?l=linux-netdev&m=139232263419315&w=2http://marc.info/?l=linux-netdev&m=139217088107122&w=2
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Dave Jones <davej@redhat.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 0abdd7a81b ("dma-debug: introduce debug_dma_assert_idle()") was
reworked to expand the overlap counter to the full range expressable by
3 tag bits, but it has a thinko in treating the overlap counter as a
pure reference count for the entry.
Instead of deleting when the reference-count drops to zero, we need to
delete when the overlap-count drops below zero. Also, when detecting
overflow we can just test the overlap-count > MAX rather than applying
special meaning to 0.
Regression report available here:
http://marc.info/?l=linux-netdev&m=139073373932386&w=2
This patch, now tested on the original net_dma case, sees the expected
handful of reports before the eventual data corruption occurs.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Record actively mapped pages and provide an api for asserting a given
page is dma inactive before execution proceeds. Placing
debug_dma_assert_idle() in cow_user_page() flagged the violation of the
dma-api in the NET_DMA implementation (see commit 7787380336 "net_dma:
mark broken").
The implementation includes the capability to count, in a limited way,
repeat mappings of the same page that occur without an intervening
unmap. This 'overlap' counter is limited to the few bits of tag space
in a radix tree. This mechanism is added to mitigate false negative
cases where, for example, a page is dma mapped twice and
debug_dma_assert_idle() is called after the page is un-mapped once.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There were reports of the igb driver unmapping buffers without calling
dma_mapping_error. On closer inspection issues were found in the DMA
debug API and how it handled multiple mappings of the same buffer.
The issue I found is the fact that the debug_dma_mapping_error would
only set the map_err_type to MAP_ERR_CHECKED in the case that the was
only one match for device and device address. However in the case of
non-IOMMU, multiple addresses existed and as a result it was not setting
this field once a second mapping was instantiated. I have resolved this
by changing the search so that it instead will now set MAP_ERR_CHECKED
on the first buffer that matches the device and DMA address that is
currently in the state MAP_ERR_NOT_CHECKED.
A secondary side effect of this patch is that in the case of multiple
buffers using the same address only the last mapping will have a valid
map_err_type. The previous mappings will all end up with map_err_type
set to MAP_ERR_CHECKED because of the dma_mapping_error call in
debug_dma_map_page. However this behavior may be preferable as it means
you will likely only see one real error per multi-mapped buffer, versus
the current behavior of multiple false errors mer multi-mapped buffer.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Shuah Khan <shuah.khan@hp.com>
Tested-by: Shuah Khan <shuah.khan@hp.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In check_unmap() it is possible to get into a dead-locked state if
dma_mapping_error is called. The problem is that the bucket is locked in
check_unmap, and locked again by debug_dma_mapping_error which is called
by dma_mapping_error. To resolve that we must release the lock on the
bucket before making the call to dma_mapping_error.
[akpm@linux-foundation.org: restore 80-col trickery to be consistent with the rest of the file]
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Shuah Khan <shuah.khan@hp.com>
Tested-by: Shuah Khan <shuah.khan@hp.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma-debug depends on get_dma_ops() interface. Several architectures
do not define dma_ops and get_dma_ops(). When dma debug interfaces are
used on an architecture (e.g: c6x) that doesn't define get_dmap_ops(),
compilation fails. Changing dma-debug to call dma_mapping_error() instead
of defining its own that calls get_dma_ops(), such that the internal use of
dma_mapping_error() doesn't interfere with the debug_dma_mapping_error()
interface's mapping error checks. Moving dma_mapping_error() checks in
check_unmap() under the dma debug entry not found is sufficient to fix the
problem.
Reference: https://lkml.org/lkml/2012/10/26/367
Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Reported-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
Add dma-debug interface debug_dma_mapping_error() to debug
drivers that fail to check dma mapping errors on addresses
returned by dma_map_single() and dma_map_page() interfaces.
This interface clears a flag set by debug_dma_map_page() to
indicate that dma_mapping_error() has been called by the
driver. When driver does unmap, debug_dma_unmap() checks the
flag and if this flag is still set, prints warning message
that includes call trace that leads up to the unmap. This
interface can be called from dma_mapping_error() routines to
enable dma mapping error check debugging.
Tested: Intel iommu and swiotlb (iommu=soft) on x86-64 with
CONFIG_DMA_API_DEBUG enabled and disabled.
Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
If there is only one match, the unique matched entry should be returned.
Without the fix, the upcoming dma debug interfaces ("dma-debug: new
interfaces to debug dma mapping errors") can't work reliably because
only device and dma_addr are passed to dma_mapping_error().
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Tested-by: Shuah Khan <shuah.khan@hp.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove local BUS_NOTIFY_UNBOUND_DRIVER define. This is not used since
BUS_NOTIFY_UNBOUND_DRIVER is defined in include/linux/device.h
Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Even though it has "bool" in the name, you have pass a u32 pointer to
debugfs_create_bool(). Otherwise you get memory corruption in
write_file_bool(). Fortunately in this case the corruption happens in
an alignment hole between variables so it doesn't cause any problems.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Saving stack trace can take a while and once the entry
is allocated free_entries_lock is no longer needed.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
As part of the removal of get_driver()/put_driver(), this patch
(as1512) gets rid of various useless and unnecessary calls in several
drivers. In some cases it may be desirable to pin the driver by
calling try_module_get(), but that can be done later.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: "David S. Miller" <davem@davemloft.net>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Michael Buesch <m@bues.ch>
CC: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
cppcheck reported:
[lib/dma-debug.c:248] -> [lib/dma-debug.c:248]: (style) Same expression on both sides of '=='.
Signed-off-by: Thomas Jarosch <thomas.jarosch@intra2net.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
There are no modular calls here, so just the minimal header for
the EXPORT_SYMBOL macro will suffice.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Summary:
Users of the pci_dma_sync_single_* api allow users to sync address ranges within
the range of a mapped entry (i.e. you can dma map address X to dma_addr_t A and
then pci_dma_sync_single on dma_addr_t A+1. The dma-debug library however
assume dma syncs will always occur using the base address of a mapped region,
and uses that assumption to find entries in its hash table. Since thats often
(but not always the case), the dma debug library can give us false errors about
missing entries, which are reported as syncing of memory not allocated by the
driver. This was noted in the cxgb3 driver as this error:
WARNING: at lib/dma-debug.c:902 check_sync+0xdd/0x48c()
Hardware name: To be filled by O.E.M.
cxgb3 0000:01:00.0: DMA-API: device driver tries to sync DMA memory it has not
allocated [device address=0x00000000fff97800] [size=1984 bytes]
Modules linked in: autofs4 sunrpc cpufreq_ondemand acpi_cpufreq freq_table
mperf ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 uinput
snd_hda_codec_intelhdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec
snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer e1000e snd soundcore r8169
cxgb3 iTCO_wdt snd_page_alloc mii shpchp i2c_i801 iTCO_vendor_support mdio
microcode firewire_ohci firewire_core crc_itu_t ata_generic pata_acpi i915
drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded:
scsi_wait_scan]
Pid: 1818, comm: ifconfig Not tainted 2.6.35-0.23.rc3.git6.fc14.x86_64 #1
Call Trace:
[<ffffffff81050f71>] warn_slowpath_common+0x85/0x9d
[<ffffffff8105102c>] warn_slowpath_fmt+0x46/0x48
[<ffffffff8124658e>] ? check_sync+0x39/0x48c
[<ffffffff8107c470>] ? trace_hardirqs_on+0xd/0xf
[<ffffffff81246632>] check_sync+0xdd/0x48c
[<ffffffff81246ca6>] debug_dma_sync_single_for_device+0x3f/0x41
[<ffffffffa011615c>] ? pci_map_page+0x84/0x97 [cxgb3]
[<ffffffffa0117bc3>] pci_dma_sync_single_for_device.clone.0+0x65/0x6e [cxgb3]
[<ffffffffa0117ed1>] refill_fl+0x305/0x30a [cxgb3]
[<ffffffffa011857d>] t3_sge_alloc_qset+0x6a7/0x821 [cxgb3]
[<ffffffffa010a07b>] cxgb_up+0x4d0/0xe62 [cxgb3]
[<ffffffff81086037>] ? __module_text_address+0x12/0x58
[<ffffffffa010aa4c>] cxgb_open+0x3f/0x309 [cxgb3]
[<ffffffff813e9f6c>] __dev_open+0x8e/0xbc
[<ffffffff813e7ca5>] __dev_change_flags+0xbe/0x142
[<ffffffff813e9ea8>] dev_change_flags+0x21/0x57
[<ffffffff81445937>] devinet_ioctl+0x29a/0x54b
[<ffffffff811f9a87>] ? inode_has_perm+0xaa/0xce
[<ffffffff81446ed2>] inet_ioctl+0x8f/0xa7
[<ffffffff813d683a>] sock_do_ioctl+0x29/0x48
[<ffffffff813d6c83>] sock_ioctl+0x213/0x222
[<ffffffff81137f78>] vfs_ioctl+0x32/0xa6
[<ffffffff811384e2>] do_vfs_ioctl+0x47a/0x4b3
[<ffffffff81138571>] sys_ioctl+0x56/0x79
[<ffffffff81009c32>] system_call_fastpath+0x16/0x1b
---[ end trace 69a4d4cc77b58004 ]---
(some edits by Joerg Roedel)
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Jay Fenalson <fenlason@redhat.com>
CC: Divy LeRay <divy@chelsio.com>
CC: Stanislaw Gruszka <sgruszka@redhat.com>
CC: Joerg Roedel <joerg.roedel@amd.com>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
When driver leak dma mapping, print additional information about one of
leaked entries, to to help investigate problem. Patch should be useful
for debugging drivers, which maps many different class of buffers.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Earlier in this function we set the last byte of "buf" to NULL so we
always hit the break statement and "i" is never equal to NAME_MAX_LEN.
This patch doesn't change how the driver works but it silences a Smatch
warning and it makes it clearer that we don't write past the end of the
array.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
warning: symbol 'filter_fops' was not declared. Should it be static?
Signed-off-by: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
There is no need to perform full BIDIR sync (copying the buffers in case
of swiotlb and similar schemes) if we know that the owner (CPU or device)
hasn't altered the data.
Addresses the false-positive reported at
http://bugzilla.kernel.org/show_bug.cgi?id=14169
Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>
Cc: David Miller <davem@davemloft.net>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stephen Rothwell reported the following build warning:
lib/dma-debug.c: In function 'dma_debug_device_change':
lib/dma-debug.c:680: warning: 'return' with no value, in function returning non-void
Introduced by commit f797d9881b
("dma-debug: Do not add notifier when dma debugging is disabled").
Return 0 [notify-done] when disabled. (this is standard bus notifier behavior.)
Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
LKML-Reference: <20091231125624.GA14666@liondog.tnic>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If CONFIG_HAVE_DMA_API_DEBUG is defined and "dma_debug=off" is
specified on the kernel command line, when you detach a driver from a
device you can cause the following NULL pointer dereference:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c0580d35>] dma_debug_device_change+0x5d/0x117
The problem is that the dma_debug_device_change notifier function is
added to the bus notifier chain even though the dma_entry_hash array
was never initialized. If dma debugging is disabled, this patch both
prevents dma_debug_device_change notifiers from being added to the
chain, and additionally ensures that the dma_debug_device_change
notifier function is a no-op.
Cc: stable@kernel.org
Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
