Commit Graph

6 Commits

Author SHA1 Message Date
Paul Mundt 0ea820cf9b sh: Move over to dynamically allocated FPU context.
This follows the x86 xstate changes and implements a task_xstate slab
cache that is dynamically sized to match one of hard FP/soft FP/FPU-less.

This also tidies up and consolidates some of the SH-2A/SH-4 FPU
fragmentation. Now fpu state restorers are commonly defined, with the
init_fpu()/fpu_init() mess reworked to follow the x86 convention.
The fpu_init() register initialization has been replaced by xstate setup
followed by writing out to hardware via the standard restore path.

As init_fpu() now performs a slab allocation a secondary lighterweight
restorer is also introduced for the context switch.

In the future the DSP state will be rolled in here, too.

More work remains for math emulation and the SH-5 FPU, which presently
uses its own special (UP-only) interfaces.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2010-01-13 12:51:40 +09:00
Stuart Menefy d3ea9fa0a5 sh: Minor optimisations to FPU handling
A number of small optimisations to FPU handling, in particular:

 - move the task USEDFPU flag from the thread_info flags field (which
   is accessed asynchronously to the thread) to a new status field,
   which is only accessed by the thread itself. This allows locking to
   be removed in most cases, or can be reduced to a preempt_lock().
   This mimics the i386 behaviour.

 - move the modification of regs->sr and thread_info->status flags out
   of save_fpu() to __unlazy_fpu(). This gives the compiler a better
   chance to optimise things, as well as making save_fpu() symmetrical
   with restore_fpu() and init_fpu().

 - implement prepare_to_copy(), so that when creating a thread, we can
   unlazy the FPU prior to copying the thread data structures.

Also make sure that the FPU is disabled while in the kernel, in
particular while booting, and for newly created kernel threads,

In a very artificial benchmark, the execution time for 2500000
context switches was reduced from 50 to 45 seconds.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-11-24 17:45:38 +09:00
Paul Mundt d3efbdd6c5 sh: Fix up the math-emu build.
math-emu wasn't converted for the trap_no/errno_code changes,
get it building again.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-06-11 15:57:42 +09:00
Simon Arlott e868d61272 spelling fixes: arch/sh/
Spelling fixes in arch/sh/.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-05-21 14:31:39 +09:00
Paul Mundt 2914d4da17 sh: Kill off remaining config.h references.
A few of these managed to sneak back in, get rid of them once
and for all.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-10-03 13:19:02 +09:00
Takashi YOSHII 4b565680d1 sh: math-emu support
This implements initial math-emu support, aimed primarily at SH-3.

Signed-off-by: Takashi YOSHII <takasi-y@ops.dti.ne.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-09-27 17:15:32 +09:00