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>
The non-rt signal handling was never really used, so we don't break
anything. This patch also cleans up the signal stack-frame to make
it independent from the processor configuration. It also improves
the method used for controlling single-stepping. We now save and
restore the 'icountlevel' register that controls single stepping
and set or clear the saved state to enable or disable it.
Signed-off-by: Chris Zankel <chris@zankel.net>
The header files in the asm-xtensa directory are not clean and
'make headers_check' fails. This is a first patch to fix most of
the header files. It removes unnecessary include statements and
adds some that are required for building the kernel. The linker
script required some updates or the linking stage would fail.
Signed-off-by: Chris Zankel <chris@zankel.net>
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>
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>
