The Xtensa architecture allows to define custom instructions and
registers. Registers that are bound to a coprocessor are only
accessible if the corresponding enable bit is set, which allows
to implement a 'lazy' context switch mechanism. Other registers
needs to be saved and restore at the time of the context switch
or during interrupt handling.
This patch adds support for these additional states:
- save and restore registers that are used by the compiler upon
interrupt entry and exit.
- context switch additional registers unbound to any coprocessor
- 'lazy' context switch of registers bound to a coprocessor
- ptrace interface to provide access to additional registers
- update configuration files in include/asm-xtensa/variant-fsf
Signed-off-by: Chris Zankel <chris@zankel.net>
Use the architecture specific __cmpxchg_u32 for 32 bits cmpxchg)_local. Else,
use the new generic cmpxchg_local (disables interrupt).
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
tas() has no users, so get rid of it.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: <linux-arch@vger.kernel.org>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Xtensa port contained many header files that were never needed. This
rather lengthy patch removes all those files. Unfortunately, there were
many dependencies that needed to be updated, so this patch touches quite a
few source files.
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
set_wmb should not be used in the kernel because it just confuses the
code more and has no benefit. Since it is not currently used in the
kernel this patch removes it so that new code does not include it.
All archs define set_wmb(var, value) to do { var = value; wmb(); }
while(0) except ia64 and sparc which use a mb() instead. But this is
still moot since it is not used anyway.
Hasn't been tested on any archs but x86 and x86_64 (and only compiled
tested)
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove io_remap_page_range() from all of Linux 2.6.x (as requested and
suggested by Randy Dunlap) and minor clean-ups.
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The attached patches provides part 6 of an architecture implementation for the
Tensilica Xtensa CPU series.
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Chris Zankel