Brian Foster [Wed, 20 Jul 2016 01:15:28 +0000 (11:15 +1000)]
xfs: track and serialize in-flight async buffers against unmount
Newly allocated XFS metadata buffers are added to the LRU once the hold
count is released, which typically occurs after I/O completion. There is
no other mechanism at current that tracks the existence or I/O state of
a new buffer. Further, readahead I/O tends to be submitted
asynchronously by nature, which means the I/O can remain in flight and
actually complete long after the calling context is gone. This means
that file descriptors or any other holds on the filesystem can be
released, allowing the filesystem to be unmounted while I/O is still in
flight. When I/O completion occurs, core data structures may have been
freed, causing completion to run into invalid memory accesses and likely
to panic.
This problem is reproduced on XFS via directory readahead. A filesystem
is mounted, a directory is opened/closed and the filesystem immediately
unmounted. The open/close cycle triggers a directory readahead that if
delayed long enough, runs buffer I/O completion after the unmount has
completed.
To address this problem, add a mechanism to track all in-flight,
asynchronous buffers using per-cpu counters in the buftarg. The buffer
is accounted on the first I/O submission after the current reference is
acquired and unaccounted once the buffer is returned to the LRU or
freed. Update xfs_wait_buftarg() to wait on all in-flight I/O before
walking the LRU list. Once in-flight I/O has completed and the workqueue
has drained, all new buffers should have been released onto the LRU.
Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Brian Foster [Wed, 20 Jul 2016 01:13:43 +0000 (11:13 +1000)]
xfs: exclude never-released buffers from buftarg I/O accounting
The upcoming buftarg I/O accounting mechanism maintains a count of
all buffers that have undergone I/O in the current hold-release
cycle. Certain buffers associated with core infrastructure (e.g.,
the xfs_mount superblock buffer, log buffers) are never released,
however. This means that accounting I/O submission on such buffers
elevates the buftarg count indefinitely and could lead to lockup on
unmount.
Define a new buffer flag to explicitly exclude buffers from buftarg
I/O accounting. Set the flag on the superblock and associated log
buffers.
Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Eric Sandeen [Wed, 20 Jul 2016 00:54:09 +0000 (10:54 +1000)]
xfs: don't reset b_retries to 0 on every failure
With the code as it stands today, b_retries never increments because
it gets reset to 0 in the error callback.
Remove that, and fix a similar problem where the first retry time
was constantly being overwritten, which defeated the timeout tunable
as well. We now only set first retry time if a non-zero timeout is
set, to match the behavior of only incrementing retries if a retry
value is set.
This way max retries & timeouts consistently take effect after a
tunable is set, rather than acting retroactively on a buffer which
has failed at some point in the past and has accumulated state from
those prior failures.
Thanks to dchinner for talking through this with me.
Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Eric Sandeen [Wed, 20 Jul 2016 00:48:51 +0000 (10:48 +1000)]
xfs: fix xfs_error_get_cfg for negative errnos
xfs_error_get_cfg() is called with bp->b_error as an arg, which is
negative, so the switch statement won't ever find any matches.
This results in only the default error handler having any effect, as
EIO/ENOSPC/ENODEV get ignored due to the wrong sign.
It seems simplest to always flip the error sign to positive, so that
we can handle either negative errors in bp->b_error, or possibly a
positive errno via something like xfs_error_get_cfg(EIO) - this
future-proofs the function.
Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Dan Carpenter [Wed, 20 Jul 2016 00:37:13 +0000 (10:37 +1000)]
xfs: don't allow negative error tags
Errors go from zero which means no error to XFS_ERRTAG_MAX (22). My
static checker complains that xfs_errortag_add() puts an upper bound on
this but not a lower bound. Let's fix it by making it unsigned.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
When calling fdget() in xfs_ioc_swapext(), we need to verify that
the file descriptors passed into the ioctl point to XFS inodes
before we start operations on them. If we don't do this, we could be
referencing arbitrary kernel memory as an XFS inode. THis could lead
to memory corruption and/or performing locking operations on
attacker-chosen structures in kernel memory.
Darrick J. Wong [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: refactor btree maxlevels computation
Create a common function to calculate the maximum height of a per-AG
btree. This will eventually be used by the rmapbt and refcountbt
code to calculate appropriate maxlevels values for each. This is
important because the verifiers and the transaction block
reservations depend on accurate estimates of how many blocks are
needed to satisfy a btree split.
We were mistakenly using the max bnobt height for all the btrees,
which creates a dangerous situation since the larger records and
keys in an rmapbt make it very possible that the rmapbt will be
taller than the bnobt and so we can run out of transaction block
reservation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Darrick J. Wong [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: convert list of extents to free into a regular list
In struct xfs_bmap_free, convert the open-coded free extent list to
a regular list, then use list_sort to sort it prior to processing.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Dave Chinner [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: separate freelist fixing into a separate helper
Break up xfs_free_extent() into a helper that fixes the freelist.
This helper will be used subsequently to ensure the freelist during
deferred rmap processing.
[darrick: refactor to put this at the head of the patchset]
Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Darrick J. Wong [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: rearrange xfs_bmap_add_free parameters
This is already in xfsprogs' libxfs, so port it to the kernel.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Darrick J. Wong [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: check for a valid error_tag in errortag_add
Currently we don't check the error_tag when someone's trying to set up
error injection testing. If userspace passes in a value we don't know
about, send back an error. This will help xfstests to _notrun a test
that uses error injection to test things like log replay.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Darrick J. Wong [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: enable buffer deadlock postmortem diagnosis via ftrace
Create a second buf_trylock tracepoint so that we can distinguish
between a successful and a failed trylock. With this piece, we can
use a script to look at the ftrace output to detect buffer deadlocks.
[dchinner: update to if/else as per hch's suggestion]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Darrick J. Wong [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: check offsets of variable length structures
Some of the directory/attr structures contain variable-length objects,
so the enclosing structure doesn't have a meaningful fixed size at
compile time. We can check the offsets of the members before the
variable-length member, so do those.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Brian Foster [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: refactor xfs_reserve_blocks() to handle ENOSPC correctly
xfs_reserve_blocks() is responsible to update the XFS reserved block
pool count at mount time or based on user request. When the caller
requests to increase the reserve pool, blocks must be allocated from
the global counters such that they are no longer available for
general purpose use. If the requested reserve pool size is too
large, XFS reserves what blocks are available. The implementation
requires looking at the percpu counters and making an educated guess
as to how many blocks to try and allocate from xfs_mod_fdblocks(),
which can return -ENOSPC if the guess was not accurate due to
counters being modified in parallel.
xfs_reserve_blocks() retries the guess in this scenario until the
allocation succeeds or it is determined that there is no space
available in the fs. While not easily reproducible in the current
form, the retry code doesn't actually work correctly if
xfs_mod_fdblocks() actually fails. The problem is that the percpu
calculations use the m_resblks counter to determine how many blocks
to allocate, but unconditionally update m_resblks before the block
allocation has actually succeeded. Therefore, if xfs_mod_fdblocks()
fails, the code jumps to the retry label and uses the already
updated m_resblks value to determine how many blocks to try and
allocate. If the percpu counters previously suggested that the
entire request was available, fdblocks_delta could end up set to 0.
In that case, m_resblks is updated to the requested value, yet no
blocks have been reserved at all.
Refactor xfs_reserve_blocks() to use an explicit loop and make the
code easier to follow. Since we have to drop the spinlock across the
xfs_mod_fdblocks() call, use a delta value for m_resblks as well and
only apply the delta once allocation succeeds.
[dchinner: convert to do {} while() loop]
Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Brian Foster [Tue, 21 Jun 2016 01:53:28 +0000 (11:53 +1000)]
xfs: cancel eofblocks background trimming on remount read-only
The filesystem quiesce sequence performs the operations necessary to
drain all background work, push pending transactions through the log
infrastructure and wait on I/O resulting from the final AIL push. We
have had reports of remount,ro hangs in xfs_log_quiesce() ->
xfs_wait_buftarg(), however, and some instrumentation code to detect
transaction commits at this point in the quiesce sequence has inculpated
the eofblocks background scanner as a cause.
While higher level remount code generally prevents user modifications by
the time the filesystem has made it to xfs_log_quiesce(), the background
scanner may still be alive and can perform pending work at any time. If
this occurs between the xfs_log_force() and xfs_wait_buftarg() calls
within xfs_log_quiesce(), this can lead to an indefinite lockup in
xfs_wait_buftarg().
To prevent this problem, cancel the background eofblocks scan worker
during the remount read-only quiesce sequence. This suspends background
trimming when a filesystem is remounted read-only. This is only done in
the remount path because the freeze codepath has already locked out new
transactions by the time the filesystem attempts to quiesce (and thus
waiting on an active work item could deadlock). Kick the eofblocks
worker to pick up where it left off once an fs is remounted back to
read-write.
Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
We'll want to use this code for large offsets now that we're
skipping holes and unwritten extents efficiently. Also rename it to
xfs_zero_range to be a bit more descriptive, and tell the caller if
we actually did any zeroing.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Note that this removes support for the untested FIEMAP_FLAG_XATTR. It
could be added relatively easily with iomap ops for the attr fork, but
without test coverage I don't feel safe doing this.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Convert XFS to use the new iomap based multipage write path. This involves
implementing the ->iomap_begin and ->iomap_end methods, and switching the
buffered file write, page_mkwrite and xfs_iozero paths to the new iomap
helpers.
With this change __xfs_get_blocks will never be used for buffered writes,
and the code handling them can be removed.
Based on earlier code from Dave Chinner.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs: reorder zeroing and flushing sequence in truncate
Currently zeroing out blocks and waiting for writeout is a bit of a mess in
truncate. This patch gives it a clear order in preparation for the iomap
path:
(1) we first wait for any direct I/O to complete to prevent any races
for it
(2) we then perform the actual zeroing, and only use the truncate_page
helpers for truncating down. The truncate up case already is
handled by the separate call to xfs_zero_eof.
(3) only then we write back dirty data, as zeroing block may cause
dirty pages when using either xfs_zero_eof or the new iomap
infrastructure.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs: make xfs_bmbt_to_iomap available outside of xfs_pnfs.c
And ensure it works for RT subvolume files an set the block device,
both of which will be needed to be able to use the function in the
buffered write path.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Add infrastructure for multipage buffered writes. This is implemented
using an main iterator that applies an actor function to a range that
can be written.
This infrastucture is used to implement a buffered write helper, one
to zero file ranges and one to implement the ->page_mkwrite VM
operations. All of them borrow a fair amount of code from fs/buffers.
for now by using an internal version of __block_write_begin that
gets passed an iomap and builds the corresponding buffer head.
The file system is gets a set of paired ->iomap_begin and ->iomap_end
calls which allow it to map/reserve a range and get a notification
once the write code is finished with it.
Based on earlier code from Dave Chinner.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Dave Chinner [Wed, 1 Jun 2016 07:38:15 +0000 (17:38 +1000)]
xfs: reduce lock hold times in buffer writeback
When we have a lot of metadata to flush from the AIL, the buffer
list can get very long. The current submission code tries to batch
submission to optimise IO order of the metadata (i.e. ascending
block order) to maximise block layer merging or IO to adjacent
metadata blocks.
Unfortunately, the method used can result in long lock times
occurring as buffers locked early on in the buffer list might not be
dispatched until the end of the IO licst processing. This is because
sorting does not occur util after the buffer list has been processed
and the buffers that are going to be submitted are locked. Hence
when the buffer list is several thousand buffers long, the lock hold
times before IO dispatch can be significant.
To fix this, sort the buffer list before we start trying to lock and
submit buffers. This means we can now submit buffers immediately
after they are locked, allowing merging to occur immediately on the
plug and dispatch to occur as quickly as possible. This means there
is minimal delay between locking the buffer and IO submission
occuring, hence reducing the worst case lock hold times seen during
delayed write buffer IO submission signficantly.
Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs: define XFS_IOC_FREEZE even if FIFREEZE is defined
And the same for XFS_IOC_THAW. Just because we now have a common
version of the ioctl we still need to provide the old name for it
for anyone using those.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Brian Foster [Wed, 1 Jun 2016 07:38:15 +0000 (17:38 +1000)]
xfs: remove spurious shutdown type check from xfs_bmap_finish()
The static checker reports that after commit 8d99fe92fed0 ("xfs: fix
efi/efd error handling to avoid fs shutdown hangs"), the code has been
reworked such that error == -EFSCORRUPTED is not possible in this
codepath.
Remove the spurious error check and just use SHUTDOWN_META_IO_ERROR
unconditionally.
Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Brian Foster [Wed, 1 Jun 2016 07:38:12 +0000 (17:38 +1000)]
xfs: fix broken multi-fsb buffer logging
Multi-block buffers are logged based on buffer offset in
xfs_trans_log_buf(). xfs_buf_item_log() ultimately walks each mapping in
the buffer and marks the associated range to be logged in the
xfs_buf_log_format bitmap for that mapping. This code is broken,
however, in that it marks the actual buffer offsets of the associated
range in each bitmap rather than shifting to the byte range for that
particular mapping.
For example, on a 4k fsb fs, buffer offset 4096 refers to the first byte
of the second mapping in the buffer. This means byte 0 of the second log
format bitmap should be tagged as dirty. Instead, the current code marks
byte offset 4096 of the second log format bitmap, which is invalid and
potentially out of range of the mapping.
As a result of this, the log item format code invoked at transaction
commit time is not be able to correctly identify what parts of the
buffer to copy into log vectors. This can lead to NULL log vector
pointer dereferences in CIL push context if the item format code was not
able to locate any dirty ranges at all. This crash has been reproduced
on a 4k FSB filesystem using 16k directory blocks where an unlink
operation happened not to log anything in the first block of the
mapping. The logged offsets were all over 4k, marked as such in the
subsequent log format mappings, and thus left the transaction with an
xfs_log_item that is marked DIRTY but without any logged regions.
Further, even when the logged regions are marked correctly in the buffer
log format bitmaps, the format code doesn't copy the correct ranges of
the buffer into the log. This means that any logged region beyond the
first block of a multi-block buffer is subject to corruption after a
crash and log recovery sequence. This is due to a failure to convert the
mapping bm_len field from basic blocks to bytes in the buffer offset
tracking code in xfs_buf_item_format().
Update xfs_buf_item_log() to convert buffer offsets to segment relative
offsets when logging multi-block buffers. This ensures that the modified
regions of a buffer are logged correctly and avoids the aforementioned
crash. Also update xfs_buf_item_format() to correctly track the source
offset into the buffer for the log vector formatting code. This ensures
that the correct data is copied into the log.
Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
George Spelvin [Sun, 29 May 2016 05:26:41 +0000 (01:26 -0400)]
Rename other copy of hash_string to hashlen_string
The original name was simply hash_string(), but that conflicted with a
function with that name in drivers/base/power/trace.c, and I decided
that calling it "hashlen_" was better anyway.
But you have to do it in two places.
[ This caused build errors for architectures that don't define
CONFIG_DCACHE_WORD_ACCESS - Linus ]
Mikulas Patocka [Tue, 24 May 2016 20:49:18 +0000 (22:49 +0200)]
hpfs: implement the show_options method
The HPFS filesystem used generic_show_options to produce string that is
displayed in /proc/mounts. However, there is a problem that the options
may disappear after remount. If we mount the filesystem with option1
and then remount it with option2, /proc/mounts should show both option1
and option2, however it only shows option2 because the whole option
string is replaced with replace_mount_options in hpfs_remount_fs.
To fix this bug, implement the hpfs_show_options function that prints
options that are currently selected.
Mikulas Patocka [Tue, 24 May 2016 20:48:33 +0000 (22:48 +0200)]
affs: fix remount failure when there are no options changed
Commit c8f33d0bec99 ("affs: kstrdup() memory handling") checks if the
kstrdup function returns NULL due to out-of-memory condition.
However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL. In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists. The mount syscall then fails with
ENOMEM.
This patch fixes the bug. We fail with ENOMEM only if data is non-NULL.
The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).
Mikulas Patocka [Tue, 24 May 2016 20:47:00 +0000 (22:47 +0200)]
hpfs: fix remount failure when there are no options changed
Commit ce657611baf9 ("hpfs: kstrdup() out of memory handling") checks if
the kstrdup function returns NULL due to out-of-memory condition.
However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL. In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists. The mount syscall then fails with
ENOMEM.
This patch fixes the bug. We fail with ENOMEM only if data is non-NULL.
The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).
Fixes: ce657611baf9 ("hpfs: kstrdup() out of memory handling") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
VDSO:
- Build microMIPS VDSO for microMIPS kernels.
- Fix aliasing warning by building with `-fno-strict-aliasing' for
debugging but also tracing them might result in recursion.
Misc:
- Add missing FROZEN hotplug notifier transitions.
- Fix clk binding example for varioius PIC32 devices.
- Fix cpu interrupt controller node-names in the DT files.
- Fix XPA CPU feature separation.
- Fix write_gc0_* macros when writing zero.
- Add inline asm encoding helpers.
- Add missing VZ accessor microMIPS encodings.
- Fix little endian microMIPS MSA encodings.
- Add 64-bit HTW fields and fix its configuration.
- Fix sigreturn via VDSO on microMIPS kernel.
- Lots of typo fixes.
- Add definitions of SegCtl registers and use them"
Linus Torvalds [Sat, 28 May 2016 23:15:25 +0000 (16:15 -0700)]
Merge branch 'hash' of git://ftp.sciencehorizons.net/linux
Pull string hash improvements from George Spelvin:
"This series does several related things:
- Makes the dcache hash (fs/namei.c) useful for general kernel use.
(Thanks to Bruce for noticing the zero-length corner case)
- Converts the string hashes in <linux/sunrpc/svcauth.h> to use the
above.
- Avoids 64-bit multiplies in hash_64() on 32-bit platforms. Two
32-bit multiplies will do well enough.
- Rids the world of the bad hash multipliers in hash_32.
This finishes the job started in commit 689de1d6ca95 ("Minimal
fix-up of bad hashing behavior of hash_64()")
The vast majority of Linux architectures have hardware support for
32x32-bit multiply and so derive no benefit from "simplified"
multipliers.
The few processors that do not (68000, h8/300 and some models of
Microblaze) have arch-specific implementations added. Those
patches are last in the series.
- Overhauls the dcache hash mixing.
The patch in commit 0fed3ac866ea ("namei: Improve hash mixing if
CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
Replaced with a much more careful design that's simultaneously
faster and better. (My own invention, as there was noting suitable
in the literature I could find. Comments welcome!)
- Modify the hash_name() loop to skip the initial HASH_MIX(). This
would let us salt the hash if we ever wanted to.
- Sort out partial_name_hash().
The hash function is declared as using a long state, even though
it's truncated to 32 bits at the end and the extra internal state
contributes nothing to the result. And some callers do odd things:
- fs/hfs/string.c only allocates 32 bits of state
- fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes
- Modify bytemask_from_count to handle inputs of 1..sizeof(long)
rather than 0..sizeof(long)-1. This would simplify users other
than full_name_hash"
Special thanks to Bruce Fields for testing and finding bugs in v1. (I
learned some humbling lessons about "obviously correct" code.)
On the arch-specific front, the m68k assembly has been tested in a
standalone test harness, I've been in contact with the Microblaze
maintainers who mostly don't care, as the hardware multiplier is never
omitted in real-world applications, and I haven't heard anything from
the H8/300 world"
* 'hash' of git://ftp.sciencehorizons.net/linux:
h8300: Add <asm/hash.h>
microblaze: Add <asm/hash.h>
m68k: Add <asm/hash.h>
<linux/hash.h>: Add support for architecture-specific functions
fs/namei.c: Improve dcache hash function
Eliminate bad hash multipliers from hash_32() and hash_64()
Change hash_64() return value to 32 bits
<linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string()
fs/namei.c: Add hashlen_string() function
Pull out string hash to <linux/stringhash.h>
George Spelvin [Wed, 25 May 2016 18:19:49 +0000 (14:19 -0400)]
h8300: Add <asm/hash.h>
This will improve the performance of hash_32() and hash_64(), but due
to complete lack of multi-bit shift instructions on H8, performance will
still be bad in surrounding code.
Designing H8-specific hash algorithms to work around that is a separate
project. (But if the maintainers would like to get in touch...)
Signed-off-by: George Spelvin <linux@sciencehorizons.net> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: uclinux-h8-devel@lists.sourceforge.jp
George Spelvin [Wed, 25 May 2016 15:06:09 +0000 (11:06 -0400)]
microblaze: Add <asm/hash.h>
Microblaze is an FPGA soft core that can be configured various ways.
If it is configured without a multiplier, the standard __hash_32()
will require a call to __mulsi3, which is a slow software loop.
Instead, use a shift-and-add sequence for the constant multiply.
GCC knows how to do this, but it's not as clever as some.
Signed-off-by: George Spelvin <linux@sciencehorizons.net> Cc: Alistair Francis <alistair.francis@xilinx.com> Cc: Michal Simek <michal.simek@xilinx.com>
George Spelvin [Fri, 27 May 2016 02:11:51 +0000 (22:11 -0400)]
<linux/hash.h>: Add support for architecture-specific functions
This is just the infrastructure; there are no users yet.
This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
the existence of <asm/hash.h>.
That file may define its own versions of various functions, and define
HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.
Included is a self-test (in lib/test_hash.c) that verifies the basics.
It is NOT in general required that the arch-specific functions compute
the same thing as the generic, but if a HAVE_* symbol is defined with
the value 1, then equality is tested.
Signed-off-by: George Spelvin <linux@sciencehorizons.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Cc: Philippe De Muyter <phdm@macq.eu> Cc: linux-m68k@lists.linux-m68k.org Cc: Alistair Francis <alistai@xilinx.com> Cc: Michal Simek <michal.simek@xilinx.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: uclinux-h8-devel@lists.sourceforge.jp
George Spelvin [Mon, 23 May 2016 11:43:58 +0000 (07:43 -0400)]
fs/namei.c: Improve dcache hash function
Patch 0fed3ac866 improved the hash mixing, but the function is slower
than necessary; there's a 7-instruction dependency chain (10 on x86)
each loop iteration.
Word-at-a-time access is a very tight loop (which is good, because
link_path_walk() is one of the hottest code paths in the entire kernel),
and the hash mixing function must not have a longer latency to avoid
slowing it down.
There do not appear to be any published fast hash functions that:
1) Operate on the input a word at a time, and
2) Don't need to know the length of the input beforehand, and
3) Have a single iterated mixing function, not needing conditional
branches or unrolling to distinguish different loop iterations.
One of the algorithms which comes closest is Yann Collet's xxHash, but
that's two dependent multiplies per word, which is too much.
The key insights in this design are:
1) Barring expensive ops like multiplies, to diffuse one input bit
across 64 bits of hash state takes at least log2(64) = 6 sequentially
dependent instructions. That is more cycles than we'd like.
2) An operation like "hash ^= hash << 13" requires a second temporary
register anyway, and on a 2-operand machine like x86, it's three
instructions.
3) A better use of a second register is to hold a two-word hash state.
With careful design, no temporaries are needed at all, so it doesn't
increase register pressure. And this gets rid of register copying
on 2-operand machines, so the code is smaller and faster.
4) Using two words of state weakens the requirement for one-round mixing;
we now have two rounds of mixing before cancellation is possible.
5) A two-word hash state also allows operations on both halves to be
done in parallel, so on a superscalar processor we get more mixing
in fewer cycles.
I ended up using a mixing function inspired by the ChaCha and Speck
round functions. It is 6 simple instructions and 3 cycles per iteration
(assuming multiply by 9 can be done by an "lea" instruction):
x ^= *input++;
y ^= x; x = ROL(x, K1);
x += y; y = ROL(y, K2);
y *= 9;
Not only is this reversible, two consecutive rounds are reversible:
if you are given the initial and final states, but not the intermediate
state, it is possible to compute both input words. This means that at
least 3 words of input are required to create a collision.
(It also has the property, used by hash_name() to avoid a branch, that
it hashes all-zero to all-zero.)
The rotate constants K1 and K2 were found by experiment. The search took
a sample of random initial states (I used 1023) and considered the effect
of flipping each of the 64 input bits on each of the 128 output bits two
rounds later. Each of the 8192 pairs can be considered a biased coin, and
adding up the Shannon entropy of all of them produces a score.
The best-scoring shifts also did well in other tests (flipping bits in y,
trying 3 or 4 rounds of mixing, flipping all 64*63/2 pairs of input bits),
so the choice was made with the additional constraint that the sum of the
shifts is odd and not too close to the word size.
The final state is then folded into a 32-bit hash value by a less carefully
optimized multiply-based scheme. This also has to be fast, as pathname
components tend to be short (the most common case is one iteration!), but
there's some room for latency, as there is a fair bit of intervening logic
before the hash value is used for anything.
(Performance verified with "bonnie++ -s 0 -n 1536:-2" on tmpfs. I need
a better benchmark; the numbers seem to show a slight dip in performance
between 4.6.0 and this patch, but they're too noisy to quote.)
Special thanks to Bruce fields for diligent testing which uncovered a
nasty fencepost error in an earlier version of this patch.
[checkpatch.pl formatting complaints noted and respectfully disagreed with.]
Signed-off-by: George Spelvin <linux@sciencehorizons.net> Tested-by: J. Bruce Fields <bfields@redhat.com>
George Spelvin [Fri, 27 May 2016 03:00:23 +0000 (23:00 -0400)]
Eliminate bad hash multipliers from hash_32() and hash_64()
The "simplified" prime multipliers made very bad hash functions, so get rid
of them. This completes the work of 689de1d6ca.
To avoid the inefficiency which was the motivation for the "simplified"
multipliers, hash_64() on 32-bit systems is changed to use a different
algorithm. It makes two calls to hash_32() instead.
drivers/media/usb/dvb-usb-v2/af9015.c uses the old GOLDEN_RATIO_PRIME_32
for some horrible reason, so it inherits a copy of the old definition.
Signed-off-by: George Spelvin <linux@sciencehorizons.net> Cc: Antti Palosaari <crope@iki.fi> Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
George Spelvin [Fri, 27 May 2016 02:22:01 +0000 (22:22 -0400)]
Change hash_64() return value to 32 bits
That's all that's ever asked for, and it makes the return
type of hash_long() consistent.
It also allows (upcoming patch) an optimized implementation
of hash_64 on 32-bit machines.
I tried adding a BUILD_BUG_ON to ensure the number of bits requested
was never more than 32 (most callers use a compile-time constant), but
adding <linux/bug.h> to <linux/hash.h> breaks the tools/perf compiler
unless tools/perf/MANIFEST is updated, and understanding that code base
well enough to update it is too much trouble. I did the rest of an
allyesconfig build with such a check, and nothing tripped.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
George Spelvin [Fri, 20 May 2016 17:31:33 +0000 (13:31 -0400)]
<linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string()
Finally, the first use of previous two patches: eliminate the
separate ad-hoc string hash functions in the sunrpc code.
Now hash_str() is a wrapper around hash_string(), and hash_mem() is
likewise a wrapper around full_name_hash().
Note that sunrpc code *does* call hash_mem() with a zero length, which
is why the previous patch needed to handle that in full_name_hash().
(Thanks, Bruce, for finding that!)
This also eliminates the only caller of hash_long which asks for
more than 32 bits of output.
The comment about the quality of hashlen_string() and full_name_hash()
is jumping the gun by a few patches; they aren't very impressive now,
but will be improved greatly later in the series.
Signed-off-by: George Spelvin <linux@sciencehorizons.net> Tested-by: J. Bruce Fields <bfields@redhat.com> Acked-by: J. Bruce Fields <bfields@redhat.com> Cc: Jeff Layton <jlayton@poochiereds.net> Cc: linux-nfs@vger.kernel.org
George Spelvin [Fri, 20 May 2016 12:41:37 +0000 (08:41 -0400)]
fs/namei.c: Add hashlen_string() function
We'd like to make more use of the highly-optimized dcache hash functions
throughout the kernel, rather than have every subsystem create its own,
and a function that hashes basic null-terminated strings is required
for that.
(The name is to emphasize that it returns both hash and length.)
It's actually useful in the dcache itself, specifically d_alloc_name().
Other uses in the next patch.
full_name_hash() is also tweaked to make it more generally useful:
1) Take a "char *" rather than "unsigned char *" argument, to
be consistent with hash_name().
2) Handle zero-length inputs. If we want more callers, we don't want
to make them worry about corner cases.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Linus Torvalds [Sat, 28 May 2016 19:38:50 +0000 (12:38 -0700)]
Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fix from Wolfram Sang:
"A fix for a regression introduced yesterday.
The regression didn't show up here locally because I did not have
PAGE_POISONING enabled. And buildbots discovered this only after it
hit your tree. Thanks to Dan for the quick response"
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: dev: use after free in detach
Linus Torvalds [Sat, 28 May 2016 19:32:01 +0000 (12:32 -0700)]
Merge tag 'chrome-platform' of git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform
Pull chrome platform updates from Olof Johansson
"A handful of Chrome driver and binding changes this merge window:
- a few patches to fix probing and configuration of pstore
- a few patches adding Elan touchpad registration on a few devices
- EC changes: a security fix dealing with max message sizes and
addition of compat_ioctl support.
- keyboard backlight control support
There was also an accidential duplicate registration of trackpads on
'Leon', which was reverted just recently"
* tag 'chrome-platform' of git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform:
Revert "platform/chrome: chromeos_laptop: Add Leon Touch"
platform/chrome: chromeos_laptop - Add Elan touchpad for Wolf
platform/chrome: chromeos_laptop - Add elan trackpad option for C720
platform/chrome: cros_ec_dev - Populate compat_ioctl
platform/chrome: cros_ec_lightbar - use name instead of ID to hide lightbar attributes
platform/chrome: cros_ec_dev - Fix security issue
platform/chrome: Add Chrome OS keyboard backlight LEDs support
platform/chrome: use to_platform_device()
platform/chrome: pstore: Move to larger record size.
platform/chrome: pstore: probe for ramoops buffer using acpi
platform/chrome: chromeos_laptop: Add Leon Touch
Linus Torvalds [Sat, 28 May 2016 19:23:12 +0000 (12:23 -0700)]
Merge tag 'sound-4.7-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull more sound updates from Takashi Iwai:
"This is the second update round for 4.7-rc1. Most of changes are
about the pending ASoC updates and fixes, including a few new drivers.
Below are some highlights:
ASoC:
- New drivers for MAX98371 and TAS5720
- SPI support for TLV320AIC32x4, along with the module split
- TDM support for STI Uniperf IPs
- Remaining topology API fixes / updates
HDA:
- A couple of Dell quirks and new Realtek codec support"
* tag 'sound-4.7-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (63 commits)
ALSA: hda - Fix headset mic detection problem for one Dell machine
spi: spi-ep93xx: Fix the PTR_ERR() argument
ALSA: hda/realtek - Add support for ALC295/ALC3254
ASoC: kirkwood: fix build failure
ALSA: hda - Fix headphone noise on Dell XPS 13 9360
ASoC: ak4642: Enable cache usage to fix crashes on resume
ASoC: twl6040: Disconnect AUX output pads on digital mute
ASoC: tlv320aic32x4: Properly implement the positive and negative pins into the mixers
rcar: src: skip disabled-SRC nodes
ASoC: max98371 Remove duplicate entry in max98371_reg
ASoC: twl6040: Select LPPLL during standby
ASoC: rsnd: don't use prohibited number to PDMACHCRn.SRS
ASoC: simple-card: Add pm callbacks to platform driver
ASoC: pxa: Fix module autoload for platform drivers
ASoC: topology: Fix memory leak in widget creation
ASoC: Add max98371 codec driver
ASoC: rsnd: count .probe/.remove for rsnd_mod_call()
ASoC: topology: Check size mismatch of ABI objects before parsing
ASoC: topology: Check failure to create a widget
ASoC: add support for TAS5720 digital amplifier
...
Linus Torvalds [Sat, 28 May 2016 19:04:17 +0000 (12:04 -0700)]
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending
Pull SCSI target updates from Nicholas Bellinger:
"Here are the outstanding target pending updates for v4.7-rc1.
The highlights this round include:
- Allow external PR/ALUA metadata path be defined at runtime via top
level configfs attribute (Lee)
- Fix target session shutdown bug for ib_srpt multi-channel (hch)
- Make TFO close_session() and shutdown_session() optional (hch)
- Drop se_sess->sess_kref + convert tcm_qla2xxx to internal kref
(hch)
- Add tcm_qla2xxx endpoint attribute for basic FC jammer (Laurence)
- Refactor iscsi-target RX/TX PDU encode/decode into common code
(Varun)
- Extend iscsit_transport with xmit_pdu, release_cmd, get_rx_pdu,
validate_parameters, and get_r2t_ttt for generic ISO offload
(Varun)
- Initial merge of cxgb iscsi-segment offload target driver (Varun)
The bulk of the changes are Chelsio's new driver, along with a number
of iscsi-target common code improvements made by Varun + Co along the
way"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (29 commits)
iscsi-target: Fix early sk_data_ready LOGIN_FLAGS_READY race
cxgbit: Use type ISCSI_CXGBIT + cxgbit tpg_np attribute
iscsi-target: Convert transport drivers to signal rdma_shutdown
iscsi-target: Make iscsi_tpg_np driver show/store use generic code
tcm_qla2xxx Add SCSI command jammer/discard capability
iscsi-target: graceful disconnect on invalid mapping to iovec
target: need_to_release is always false, remove redundant check and kfree
target: remove sess_kref and ->shutdown_session
iscsi-target: remove usage of ->shutdown_session
tcm_qla2xxx: introduce a private sess_kref
target: make close_session optional
target: make ->shutdown_session optional
target: remove acl_stop
target: consolidate and fix session shutdown
cxgbit: add files for cxgbit.ko
iscsi-target: export symbols
iscsi-target: call complete on conn_logout_comp
iscsi-target: clear tx_thread_active
iscsi-target: add new offload transport type
iscsi-target: use conn_transport->transport_type in text rsp
...
Linus Torvalds [Sat, 28 May 2016 18:04:16 +0000 (11:04 -0700)]
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma
Pull more rdma updates from Doug Ledford:
"This is the second group of code for the 4.7 merge window. It looks
large, but only in one sense. I'll get to that in a minute. The list
of changes here breaks down as follows:
- Dynamic counter infrastructure in the IB drivers
This is a sysfs based code to allow free form access to the
hardware counters RDMA devices might support so drivers don't need
to code this up repeatedly themselves
- SendOnlyFullMember multicast support
- IB router support
- A couple misc fixes
- The big item on the list: hfi1 driver updates, plus moving the hfi1
driver out of staging
There was a group of 15 patches in the hfi1 list that I thought I had
in the first pull request but they weren't. So that added to the
length of the hfi1 section here.
As far as these go, everything but the hfi1 is pretty straight
forward.
The hfi1 is, if you recall, the driver that Al had complaints about
how it used the write/writev interfaces in an overloaded fashion. The
write portion of their interface behaved like the write handler in the
IB stack proper and did bi-directional communications. The writev
interface, on the other hand, only accepts SDMA request structures.
The completions for those structures are sent back via an entirely
different event mechanism.
With the security patch, we put security checks on the write
interface, however, we also knew they would be going away soon. Now,
we've converted the write handler in the hfi1 driver to use ioctls
from the IB reserved magic area for its bidirectional communications.
With that change, Intel has addressed all of the items originally on
their TODO when they went into staging (as well as many items added to
the list later).
As such, I moved them out, and since they were the last item in the
staging/rdma directory, and I don't have immediate plans to use the
staging area again, I removed the staging/rdma area.
Because of the move out of staging, as well as a series of 5 patches
in the hfi1 driver that removed code people thought should be done in
a different way and was optional to begin with (a snoop debug
interface, an eeprom driver for an eeprom connected directory to their
hfi1 chip and not via an i2c bus, and a few other things like that),
the line count, especially the removal count, is high"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (56 commits)
staging/rdma: Remove the entire rdma subdirectory of staging
IB/core: Make device counter infrastructure dynamic
IB/hfi1: Fix pio map initialization
IB/hfi1: Correct 8051 link parameter settings
IB/hfi1: Update pkey table properly after link down or FM start
IB/rdamvt: Fix rdmavt s_ack_queue sizing
IB/rdmavt: Max atomic value should be a u8
IB/hfi1: Fix hard lockup due to not using save/restore spin lock
IB/hfi1: Add tracing support for send with invalidate opcode
IB/hfi1, qib: Add ieth to the packet header definitions
IB/hfi1: Move driver out of staging
IB/hfi1: Do not free hfi1 cdev parent structure early
IB/hfi1: Add trace message in user IOCTL handling
IB/hfi1: Remove write(), use ioctl() for user cmds
IB/hfi1: Add ioctl() interface for user commands
IB/hfi1: Remove unused user command
IB/hfi1: Remove snoop/diag interface
IB/hfi1: Remove EPROM functionality from data device
IB/hfi1: Remove UI char device
IB/hfi1: Remove multiple device cdev
...
Board "Leon" is otherwise known as "Toshiba CB35" and we already have
the entry that supports that board as of this commit : 963cb6f platform/chrome: chromeos_laptop - Add Toshiba CB35 Touch
Remove this duplicate.
Signed-off-by: Benson Leung <bleung@chromium.org> Signed-off-by: Olof Johansson <olof@lixom.net>
Dan Carpenter [Sat, 28 May 2016 05:01:46 +0000 (08:01 +0300)]
i2c: dev: use after free in detach
The call to put_i2c_dev() frees "i2c_dev" so there is a use after
free when we call cdev_del(&i2c_dev->cdev).
Fixes: d6760b14d4a1 ('i2c: dev: switch from register_chrdev to cdev API') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The corresponding FROZEN hotplug notifier transitions used on
suspend/resume are ignored. Therefore the switch case action argument
is masked with the frozen hotplug notifier transition mask.
James Hogan [Tue, 24 May 2016 08:35:11 +0000 (09:35 +0100)]
MIPS: Build microMIPS VDSO for microMIPS kernels
MicroMIPS kernels may be expected to run on microMIPS only cores which
don't support the normal MIPS instruction set, so be sure to pass the
-mmicromips flag through to the VDSO cflags.
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: <stable@vger.kernel.org> # 4.4.x-
Patchwork: https://patchwork.linux-mips.org/patch/13349/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
James Hogan [Tue, 24 May 2016 08:35:10 +0000 (09:35 +0100)]
MIPS: Fix sigreturn via VDSO on microMIPS kernel
In microMIPS kernels, handle_signal() sets the isa16 mode bit in the
vdso address so that the sigreturn trampolines (which are offset from
the VDSO) get executed as microMIPS.
However commit ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
changed the offsets to come from the VDSO image, which already have the
isa16 mode bit set correctly since they're extracted from the VDSO
shared library symbol table.
Drop the isa16 mode bit handling from handle_signal() to fix sigreturn
for cores which support both microMIPS and normal MIPS. This doesn't fix
microMIPS only cores, since the VDSO is still built for normal MIPS, but
thats a separate problem.
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: <stable@vger.kernel.org> # 4.4.x-
Patchwork: https://patchwork.linux-mips.org/patch/13348/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Antony Pavlov [Mon, 23 May 2016 11:39:00 +0000 (14:39 +0300)]
MIPS: devicetree: fix cpu interrupt controller node-names
Here is the quote from [1]:
The unit-address must match the first address specified
in the reg property of the node. If the node has no reg property,
the @ and unit-address must be omitted and the node-name alone
differentiates the node from other nodes at the same level
This patch adjusts MIPS dts-files and devicetree binding
documentation in accordance with [1].
[1] Power.org(tm) Standard for Embedded Power Architecture(tm)
Platform Requirements (ePAPR). Version 1.1 – 08 April 2011.
Chapter 2.2.1.1 Node Name Requirements
Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk> Cc: Kumar Gala <galak@codeaurora.org> Cc: linux-mips@linux-mips.org Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13345/ Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Avoid an aliasing issue causing a build error in VDSO:
In file included from include/linux/srcu.h:34:0,
from include/linux/notifier.h:15,
from ./arch/mips/include/asm/uprobes.h:9,
from include/linux/uprobes.h:61,
from include/linux/mm_types.h:13,
from ./arch/mips/include/asm/vdso.h:14,
from arch/mips/vdso/vdso.h:27,
from arch/mips/vdso/gettimeofday.c:11:
include/linux/workqueue.h: In function 'work_static':
include/linux/workqueue.h:186:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
return *work_data_bits(work) & WORK_STRUCT_STATIC;
^
cc1: all warnings being treated as errors
make[2]: *** [arch/mips/vdso/gettimeofday.o] Error 1
with a CONFIG_DEBUG_OBJECTS_WORK configuration and GCC 5.2.0. Include
`-fno-strict-aliasing' along with compiler options used, as required for
kernel code, fixing a problem present since the introduction of VDSO
with commit ebb5e78cc634 ("MIPS: Initial implementation of a VDSO").
Thanks to Tejun for diagnosing this properly!
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Cc: Tejun Heo <tj@kernel.org> Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # v4.3+
Patchwork: https://patchwork.linux-mips.org/patch/13357/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Harvey Hunt [Wed, 25 May 2016 10:06:35 +0000 (11:06 +0100)]
MIPS: lib: Mark intrinsics notrace
On certain MIPS32 devices, the ftrace tracer "function_graph" uses
__lshrdi3() during the capturing of trace data. ftrace then attempts to
trace __lshrdi3() which leads to infinite recursion and a stack overflow.
Fix this by marking __lshrdi3() as notrace. Mark the other compiler
intrinsics as notrace in case the compiler decides to use them in the
ftrace path.
James Hogan [Fri, 27 May 2016 21:25:23 +0000 (22:25 +0100)]
MIPS: Fix 64-bit HTW configuration
The Hardware page Table Walker (HTW) is being misconfigured on 64-bit
kernels. The PWSize.PS (pointer size) bit determines whether pointers
within directories are loaded as 32-bit or 64-bit addresses, but was
never being set to 1 for 64-bit kernels where the unsigned long in pgd_t
is 64-bits wide.
This actually reduces rather than improves performance when the HTW is
enabled on P6600 since the HTW is initiated lots, but walks are all
aborted due I think to bad intermediate pointers.
Since we were already taking the width of the PTEs into account by
setting PWSize.PTEW, which is the left shift applied to the page table
index *in addition to* the native pointer size, we also need to reduce
PTEW by 1 when PS=1. This is done by calculating PTEW based on the
relative size of pte_t compared to pgd_t.
Finally in order for the HTW to be used when PS=1, the appropriate
XK/XS/XU bits corresponding to the different 64-bit segments need to be
set in PWCtl. We enable only XU for now to enable walking for XUSeg.
Supporting walking for XKSeg would be a bit more involved so is left for
a future patch. It would either require the use of a per-CPU top level
base directory if supported by the HTW (a bit like pgd_current but with
a second entry pointing at swapper_pg_dir), or the HTW would prepend bit
63 of the address to the global directory index which doesn't really
match how we split user and kernel page directories.
Fixes: cab25bc7537b ("MIPS: Extend hardware table walking support to MIPS64") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13364/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
James Hogan [Fri, 27 May 2016 21:25:22 +0000 (22:25 +0100)]
MIPS: Add 64-bit HTW fields
Add field definitions for some of the 64-bit specific Hardware page
Table Walker (HTW) register fields in PWSize and PWCtl, in preparation
for fixing the 64-bit HTW configuration.
Also print these fields out along with the others in print_htw_config().
Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13363/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
James Hogan [Fri, 20 May 2016 22:28:41 +0000 (23:28 +0100)]
MIPS: Simplify DSP instruction encoding macros
Simplify the DSP instruction wrapper macros which use explicit encodings
for microMIPS and normal MIPS by using the new encoding macros and
removing duplication.
To me this makes it easier to read since it is much shorter, but it also
ensures .insn is used, preventing objdump disassembling the microMIPS
code as normal MIPS.
James Hogan [Fri, 20 May 2016 22:28:40 +0000 (23:28 +0100)]
MIPS: Add missing tlbinvf/XPA microMIPS encodings
Hardcoded MIPS instruction encodings are provided for tlbinvf, mfhc0 &
mthc0 instructions, but microMIPS encodings are missing. I doubt any
microMIPS cores exist at present which support these instructions, but
the microMIPS encodings exist, and microMIPS cores may support them in
the future. Add the missing microMIPS encodings using the new macros.
James Hogan [Fri, 20 May 2016 22:28:39 +0000 (23:28 +0100)]
MIPS: Fix little endian microMIPS MSA encodings
When the toolchain doesn't support MSA we encode MSA instructions
explicitly in assembly. Unfortunately we use .word for both MIPS and
microMIPS encodings which is wrong, since 32-bit microMIPS instructions
are made up from a pair of halfwords.
- The most significant halfword always comes first, so for little endian
builds the halves will be emitted in the wrong order.
- 32-bit alignment isn't guaranteed, so the assembler may insert a
16-bit nop instruction to pad the instruction stream to a 32-bit
boundary.
Use the new instruction encoding macros to encode microMIPS MSA
instructions correctly.
James Hogan [Fri, 20 May 2016 22:28:38 +0000 (23:28 +0100)]
MIPS: Add missing VZ accessor microMIPS encodings
Toolchains may be used which support microMIPS but not VZ instructions
(i.e. binutis 2.22 & 2.23), so extend the explicitly encoded versions of
the guest COP0 register & guest TLB access macros to support microMIPS
encodings too, using the new macros.
This prevents non-microMIPS instructions being executed in microMIPS
mode during CPU probe on cores supporting VZ (e.g. M5150), which cause
reserved instruction exceptions early during boot.
Fixes: bad50d79255a ("MIPS: Fix VZ probe gas errors with binutils <2.24") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13311/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
James Hogan [Fri, 20 May 2016 22:28:37 +0000 (23:28 +0100)]
MIPS: Add inline asm encoding helpers
To allow simplification of macros which use inline assembly to
explicitly encode instructions, add a few simple abstractions to
mipsregs.h which expand to specific microMIPS or normal MIPS encodings
depending on what type of kernel is being built:
_ASM_INSN_IF_MIPS(_enc) : Emit a 32bit MIPS instruction if microMIPS is
not enabled.
_ASM_INSN32_IF_MM(_enc) : Emit a 32bit microMIPS instruction if enabled.
_ASM_INSN16_IF_MM(_enc) : Emit a 16bit microMIPS instruction if enabled.
The macros can be used one after another since the MIPS / microMIPS
macros are mutually exclusive, for example:
projects / mirror_ubuntu-bionic-kernel.git / log