linux-toradex.git/arch/tile/lib/atomic_32.c, branch v4.5

tile: Provide atomic_{or,xor,and}

2015-07-27T12:06:24+00:00

Implement atomic logic ops -- atomic_{or,xor,and}.

For tilegx, these are relatively straightforward; the architecture
provides atomic "or" and "and", both 32-bit and 64-bit.  To support
xor we provide a loop using "cmpexch".

For the older 32-bit tilepro architecture, we have to extend
the set of low-level assembly routines to include 32-bit "and",
as well as all three 64-bit routines.  Somewhat confusingly,
some 32-bit versions are already used by the bitops inlines, with
parameter types appropriate for bitops, so we have to do a bit of
casting to match "int" to "unsigned long".

Signed-off-by: Chris Metcalf 
Signed-off-by: Peter Zijlstra (Intel) 
Link: http://lkml.kernel.org/r/1436474297-32187-1-git-send-email-cmetcalf@ezchip.com
Signed-off-by: Thomas Gleixner

tile: include: asm: use 'long long' instead of 'u64' for atomic64_t and its related functions

2013-09-27T20:08:56+00:00

atomic* value is signed value, and atomic* functions need also process
signed value (parameter value, and return value), so use 'long long'
instead of 'u64'.

After replacement, it will also fix a bug for atomic64_add_negative():
"u64 is never less than 0".

The modifications are:

  in vim, use "1,% s/\/long long/g" command.
  remove redundant '__aligned(8)'.
  be sure of 80 (and macro '\') columns limitation after replacement.

Signed-off-by: Chen Gang 
Signed-off-by: Chris Metcalf  [re-instated const cast]

tile: rework

2013-09-06T17:06:25+00:00

The macrology in cmpxchg.h was designed to allow arbitrary pointer
and integer values to be passed through the routines.  To support
cmpxchg() on 64-bit values on the 32-bit tilepro architecture, we
used the idiom "(typeof(val))(typeof(val-val))".  This way, in the
"size 8" branch of the switch, when the underlying cmpxchg routine
returns a 64-bit quantity, we cast it first to a typeof(val-val)
quantity (i.e. size_t if "val" is a pointer) with no warnings about
casting between pointers and integers of different sizes, then cast
onwards to typeof(val), again with no warnings.  If val is not a
pointer type, the additional cast is a no-op.  We can't replace the
typeof(val-val) cast with (for example) unsigned long, since then if
"val" is really a 64-bit type, we cast away the high bits.

HOWEVER, this fails with current gcc (through 4.7 at least) if "val"
is a pointer to an incomplete type.  Unfortunately gcc isn't smart
enough to realize that "val - val" will always be a size_t type
even if it's an incomplete type pointer.

Accordingly, I've reworked the way we handle the casting.  We have
given up the ability to use cmpxchg() on 64-bit values on tilepro,
which is OK in the kernel since we should use cmpxchg64() explicitly
on such values anyway.  As a result, I can just use simple "unsigned
long" casts internally.

As I reworked it, I realized it would be cleaner to move the
architecture-specific conditionals for cmpxchg and xchg out of the
atomic.h headers and into cmpxchg, and then use the cmpxchg() and
xchg() primitives directly in atomic.h and elsewhere.  This allowed
the cmpxchg.h header to stand on its own without relying on the
implicit include of it that is performed by .
It also allowed collapsing the atomic_xchg/atomic_cmpxchg routines
from atomic_{32,64}.h into atomic.h.

I improved the tests that guard the allowed size of the arguments
to the routines to use a __compiletime_error() test.  (By avoiding
the use of BUILD_BUG, I could include cmpxchg.h into bitops.h as
well and use the macros there, which is otherwise impossible due
to include order dependency issues.)

The tilepro _atomic_xxx internal methods were previously set up to
take atomic_t and atomic64_t arguments, which isn't as convenient
with the new model, so I modified them to take int or u64 arguments,
which is consistent with how they used the arguments internally
anyway, so provided some nice simplification there too.

Signed-off-by: Chris Metcalf

tile: remove support for TILE64

2013-09-03T18:53:29+00:00

This chip is no longer being actively developed for (it was superceded
by the TILEPro64 in 2008), and in any case the existing compiler and
toolchain in the community do not support it.  It's unlikely that the
kernel works with TILE64 at this point as the configuration has not been
tested in years.  The support is also awkward as it requires maintaining
a significant number of ifdefs.  So, just remove it altogether.

Signed-off-by: Chris Metcalf

tile: eliminate no-op "noatomichash" boot argument

2013-09-03T18:53:24+00:00

Signed-off-by: Chris Metcalf

arch/tile: optimize get_user/put_user and friends

2012-05-25T16:48:23+00:00

Use direct load/store for the get_user/put_user.

Previously, we would call out to a helper routine that would do the
appropriate thing and then return, handling the possible exception
internally.  Now we inline the load or store, along with a "we succeeded"
indication in a register; if the load or store faults, we write a
"we failed" indication into the same register and then return to the
following instruction.  This is more efficient and gives us more compact
code, as well as being more in line with what other architectures do.

The special futex assembly source file for TILE-Gx also disappears in
this change; we just use the same inlining idiom there as well, putting
the appropriate atomic operations directly into futex_atomic_op_inuser()
(and thus into the FUTEX_WAIT function).

The underlying atomic copy_from_user, copy_to_user functions were
renamed using the (cryptic) x86 convention as copy_from_user_ll and
copy_to_user_ll.

Signed-off-by: Chris Metcalf

atomic: use

2011-07-26T23:49:47+00:00

This allows us to move duplicated code in 
(atomic_inc_not_zero() for now) to 

Signed-off-by: Arun Sharma 
Reviewed-by: Eric Dumazet 
Cc: Ingo Molnar 
Cc: David Miller 
Cc: Eric Dumazet 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arch/tile: fix futex sanitization definition/prototype mismatch

2011-03-20T04:08:21+00:00

Commit 8d7718aa082aaf30a0b4989e1f04858952f941bc changed "int"
to "u32" in the prototypes but not the definition.
I missed this when I saw the patch go by on LKML.

We cast "u32 *" to "int *" since we are tying into the underlying
atomics framework, and atomic_t uses int as its value type.

Signed-off-by: Chris Metcalf 
Reviewed-by: Michel Lespinasse

arch/tile: fix some comments and whitespace

2011-03-10T18:14:03+00:00

This is a grab bag of changes with no actual change to generated code.
This includes whitespace and comment typos, plus a couple of stale
comments being removed.

Signed-off-by: Chris Metcalf

arch/tile: catch up with section naming convention in 2.6.35

2011-03-01T21:18:52+00:00

The convention changed to, e.g., ".data..page_aligned".  This commit
fixes the places in the tile architecture that were still using the
old convention.  One tile-specific section (.init.page) was dropped
in favor of just using an "aligned" attribute.

Sam Ravnborg  pointed out __PAGE_ALIGNED_BSS, etc.

Signed-off-by: Chris Metcalf