linux-toradex.git/arch/sh/kernel/cpu/sh2a/fpu.c, branch v3.4.1 Linux kernel for Apalis and Colibri modules sh: fix up fallout from system.h disintegration. 2012-03-30T10:29:57+00:00 Paul Mundt lethal@linux-sh.org 2012-03-30T10:29:57+00:00 f03c4866d31e913a8dbc84f7d1459abdaf0bd326 Quite a bit of fallout all over the place, nothing terribly exciting. Signed-off-by: Paul Mundt <lethal@linux-sh.org> 
Quite a bit of fallout all over the place, nothing terribly exciting.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
sh: Move over to dynamically allocated FPU context. 2010-01-13T03:51:40+00:00 Paul Mundt lethal@linux-sh.org 2010-01-13T03:51:40+00:00 0ea820cf9bf58f735ed40ec67947159c4f170012 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 The fpu_init() register initialization has been replaced by xstate setup followed by writing out to hardware via the standard restore path.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> 
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The fpu_init() register initialization has been replaced by xstate setup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>
sh: Apply the sleazy FPU changes for SH-2A FPU as well. 2009-11-24T08:56:17+00:00 Paul Mundt lethal@linux-sh.org 2009-11-24T08:56:17+00:00 0f09e197a39c081fa8c2752ee65919cb6cba963a This plugs in the fpu_counter manipulation for the SH-2A side also. Signed-off-by: Paul Mundt <lethal@linux-sh.org> 
This plugs in the fpu_counter manipulation for the SH-2A side also.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
sh: Minor optimisations to FPU handling 2009-11-24T08:45:38+00:00 Stuart Menefy stuart.menefy@st.com 2009-09-25T17:25:10+00:00 d3ea9fa0a563620fe9f416f94bb8927c64390917 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> 
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>
SH: catch negative denormal_subf1() retval in denormal_add() 2008-05-09T11:05:10+00:00 Roel Kluin 12o3l@tiscali.nl 2008-05-09T11:05:10+00:00 9731e287e08b804592191d8bffaad023154af2aa 'ix' is unsigned but denormal_subf1() may return a negative int. Signed-off-by: Roel Kluin <12o3l@tiscali.nl> Signed-off-by: Paul Mundt <lethal@linux-sh.org> 
'ix' is unsigned but denormal_subf1() may return a negative int.

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
sh: Fix occasional FPU register corruption under preempt. 2008-03-26T10:02:47+00:00 Paul Mundt lethal@linux-sh.org 2008-03-26T10:02:47+00:00 9bbafce2eec190ef7e44b0eb1095ba17ce6ad3af Presently with preempt enabled there's the possibility to be preempted after the TIF_USEDFPU test and the register save, leading to bogus state post-__switch_to(). Use an explicit preempt_disable()/enable() pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86 change. Reported-by: Takuo Koguchi <takuo.koguchi.sw@hitachi.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org> 
Presently with preempt enabled there's the possibility to be preempted
after the TIF_USEDFPU test and the register save, leading to bogus
state post-__switch_to(). Use an explicit preempt_disable()/enable()
pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86
change.

Reported-by: Takuo Koguchi <takuo.koguchi.sw@hitachi.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
sh: SH-2A FPU support. 2008-01-28T04:18:57+00:00 Paul Mundt lethal@linux-sh.org 2007-11-26T11:38:36+00:00 74d99a5e262229ee865f6f68528d10b82471ead6 Signed-off-by: Kieran Bingham <kbingham@mpc-data.co.uk> Signed-off-by: Paul Mundt <lethal@linux-sh.org> 
Signed-off-by: Kieran Bingham <kbingham@mpc-data.co.uk>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>