linux-sg2042/arch/tile/lib
Chris Metcalf 6dc9658fa1 tile: rework <asm/cmpxchg.h>
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 <asm/atomic.h>.
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 <cmetcalf@tilera.com>
2013-09-06 13:06:25 -04:00
..
Makefile tile: remove support for TILE64 2013-09-03 14:53:29 -04:00
atomic_32.c tile: rework <asm/cmpxchg.h> 2013-09-06 13:06:25 -04:00
atomic_asm_32.S tile: use proper .align directives on __ex_table sections 2013-08-30 11:56:11 -04:00
cacheflush.c tile: support FRAME_POINTER 2013-09-03 14:52:09 -04:00
checksum.c arch/tile: break out the "csum a long" function to <asm/checksum.h> 2012-07-11 16:04:57 -04:00
cpumask.c tile: export a handful of symbols appropriately 2013-02-08 13:20:36 -05:00
delay.c arch/tile: fix __ndelay etc to work better 2011-03-01 16:20:04 -05:00
exports.c tile: support ftrace on tilegx 2013-08-30 10:20:13 -04:00
memchr_32.c arch/tile: fix memchr() not to dereference memory for zero length 2010-11-24 13:57:42 -05:00
memchr_64.c tile: optimize and clean up string functions 2013-08-01 16:23:12 -04:00
memcpy_32.S tile: remove support for TILE64 2013-09-03 14:53:29 -04:00
memcpy_64.c tile: support FRAME_POINTER 2013-09-03 14:52:09 -04:00
memcpy_user_64.c tile: use proper .align directives on __ex_table sections 2013-08-30 11:56:11 -04:00
memmove.c arch/tile: minor whitespace/naming changes for string support files 2010-10-15 15:38:54 -04:00
memset_32.c tile: remove support for TILE64 2013-09-03 14:53:29 -04:00
memset_64.c tile: optimize and clean up string functions 2013-08-01 16:23:12 -04:00
spinlock_32.c arch/tile: remove inline marking of EXPORT_SYMBOL functions 2013-05-09 13:53:45 -04:00
spinlock_64.c arch/tile: finish enabling support for TILE-Gx 64-bit chip 2011-05-12 15:52:12 -04:00
spinlock_common.h arch/tile: fix bug in delay_backoff() 2012-04-02 12:13:15 -04:00
strchr_32.c tile: optimize and clean up string functions 2013-08-01 16:23:12 -04:00
strchr_64.c tile: optimize and clean up string functions 2013-08-01 16:23:12 -04:00
string-endian.h tile: optimize and clean up string functions 2013-08-01 16:23:12 -04:00
strlen_32.c tile: optimize and clean up string functions 2013-08-01 16:23:12 -04:00
strlen_64.c arch/tile: support building big-endian kernel 2012-05-25 12:48:22 -04:00
strnlen_32.c tile: optimize strnlen using SIMD instructions 2013-08-01 20:08:51 -04:00
strnlen_64.c tile: optimize strnlen using SIMD instructions 2013-08-01 20:08:51 -04:00
uaccess.c Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS 2013-04-30 17:04:09 -07:00
usercopy_32.S tile: fix strncpy_from_user bug 2013-08-30 11:56:42 -04:00
usercopy_64.S tile: fix strncpy_from_user bug 2013-08-30 11:56:42 -04:00