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linux-stable-rt/include/asm-sh/fpu.h

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sh: Bring the SH-5 FPU in line with the SH-4 FPU API. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-11-22 16:30:50 +08:00
#ifndef __ASM_SH_FPU_H
#define __ASM_SH_FPU_H
#ifndef __ASSEMBLY__
sh: Fix occasional FPU register corruption under preempt. 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>
2008-03-26 18:02:47 +08:00
#include <linux/preempt.h>
sh: Bring the SH-5 FPU in line with the SH-4 FPU API. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-11-22 16:30:50 +08:00
#include <asm/ptrace.h>
#ifdef CONFIG_SH_FPU
static inline void release_fpu(struct pt_regs *regs)
{
regs->sr |= SR_FD;
}
static inline void grab_fpu(struct pt_regs *regs)
{
regs->sr &= ~SR_FD;
}
struct task_struct;
extern void save_fpu(struct task_struct *__tsk, struct pt_regs *regs);
#else
sh: Fix TIF_USEDFPU clearing under FPU emulation. The unlazy_fpu() path calls in to save_fpu() if the task has TIF_USEDFPU set. save_fpu() being the crap API that it is has the side effect of clearing the flag itself, which presently doesn't happen if we're using FPU emulation. Fix this up for now, pending an overhaul in 2.6.26. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-03-26 18:09:21 +08:00
sh: Bring the SH-5 FPU in line with the SH-4 FPU API. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-11-22 16:30:50 +08:00
#define release_fpu(regs) do { } while (0)
#define grab_fpu(regs) do { } while (0)
sh: Fix TIF_USEDFPU clearing under FPU emulation. The unlazy_fpu() path calls in to save_fpu() if the task has TIF_USEDFPU set. save_fpu() being the crap API that it is has the side effect of clearing the flag itself, which presently doesn't happen if we're using FPU emulation. Fix this up for now, pending an overhaul in 2.6.26. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-03-26 18:09:21 +08:00
static inline void save_fpu(struct task_struct *tsk, struct pt_regs *regs)
{
clear_tsk_thread_flag(tsk, TIF_USEDFPU);
}
sh: Bring the SH-5 FPU in line with the SH-4 FPU API. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-11-22 16:30:50 +08:00
#endif
sh: SH-2A FPU support. Signed-off-by: Kieran Bingham <kbingham@mpc-data.co.uk> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-11-26 19:38:36 +08:00
extern int do_fpu_inst(unsigned short, struct pt_regs *);
sh: Fix occasional FPU register corruption under preempt. 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>
2008-03-26 18:02:47 +08:00
static inline void unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
{
preempt_disable();
if (test_tsk_thread_flag(tsk, TIF_USEDFPU))
save_fpu(tsk, regs);
preempt_enable();
}
static inline void clear_fpu(struct task_struct *tsk, struct pt_regs *regs)
{
preempt_disable();
if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {
clear_tsk_thread_flag(tsk, TIF_USEDFPU);
release_fpu(regs);
}
preempt_enable();
}
sh: Bring the SH-5 FPU in line with the SH-4 FPU API. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-11-22 16:30:50 +08:00
#endif /* __ASSEMBLY__ */
#endif /* __ASM_SH_FPU_H */