Gilles Chanteperdrix wrote: > On Fri, Apr 25, 2008 at 9:48 AM, Philippe Gerum <[EMAIL PROTECTED]> wrote: >> Gilles Chanteperdrix wrote: >> > This patch implements the _read, _set, and _cmpxchg operations on >> atomic_long_t >> > and atomic_ptr_t in user-space in include/asm-generic/atomic.h which >> should be >> > included at the end of include/asm-*/atomic.h after the definition of the >> same >> > operations for the atomic_t type and atomic64_t type on 64 bits platforms. >> > >> > These operations are the basic operations used by user-space mutexes. >> Maybe we >> > should add the xnarch_ prefix ? >> > >> >> Yes, but more generally, we should rework this to fit the existing atomic >> support in include/asm-*/atomic.h, so that we don't end up with sideways to >> what >> has been already designed to support set, get, xchg and the like, in both >> kernel >> and userland context. > > That is not exactly sideways... Linux include/asm-generic/atomic.h > defines operations for atomic_long_t. This file adds two things: > - support for atomic_long_t in user-space (where we can not include > linux include/asm-generic/atomic.h) > - support for a new type atomic_ptr_t both to kernel-space and > user-space, the aim is to avoid all the casts that would take place if > we wanted to use atomic_long_t to store pointers. > > However for this file to work, it has to be included by asm-*/atomic.h > after the definition of atomic_t (and atomic64_t on 64 bits > platforms). So linux includes asm-generic/atomic.h at the end of > asm/atomic.h, I simply reproduced this scheme with Xenomai > include/asm-*/atomic.h. >
Focusing on user-space: 1) xnarch_atomic_xchg is meant to work on long types; 2) set, get routines are not defined in that scope. If the purpose is to define integer-type ops to handle pointer-type data atomically (i.e. intptr_t), then I would rather check whether we actually need non-long support at all in user-space. In case we don't, I would simply reply on the existing implementation of asm-*/atomic.h + the set / get extensions you provide. -- Philippe. _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
