9bbafce2ee
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>
51 lines
1.0 KiB
C
51 lines
1.0 KiB
C
#ifndef __ASM_SH_FPU_H
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#define __ASM_SH_FPU_H
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#ifndef __ASSEMBLY__
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#include <linux/preempt.h>
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#include <asm/ptrace.h>
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#ifdef CONFIG_SH_FPU
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static inline void release_fpu(struct pt_regs *regs)
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{
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regs->sr |= SR_FD;
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}
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static inline void grab_fpu(struct pt_regs *regs)
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{
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regs->sr &= ~SR_FD;
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}
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struct task_struct;
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extern void save_fpu(struct task_struct *__tsk, struct pt_regs *regs);
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#else
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#define release_fpu(regs) do { } while (0)
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#define grab_fpu(regs) do { } while (0)
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#define save_fpu(tsk, regs) do { } while (0)
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#endif
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extern int do_fpu_inst(unsigned short, struct pt_regs *);
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static inline void unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
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{
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preempt_disable();
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if (test_tsk_thread_flag(tsk, TIF_USEDFPU))
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save_fpu(tsk, regs);
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preempt_enable();
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}
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static inline void clear_fpu(struct task_struct *tsk, struct pt_regs *regs)
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{
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preempt_disable();
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if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {
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clear_tsk_thread_flag(tsk, TIF_USEDFPU);
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release_fpu(regs);
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}
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preempt_enable();
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}
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_SH_FPU_H */
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