49 lines
1.7 KiB
C
49 lines
1.7 KiB
C
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/*
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* Copyright (C) 1994 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* General FPU state handling cleanups
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* Gareth Hughes <gareth@valinux.com>, May 2000
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* x86-64 work by Andi Kleen 2002
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*/
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#ifndef _ASM_X86_FPU_API_H
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#define _ASM_X86_FPU_API_H
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/*
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* Careful: __kernel_fpu_begin/end() must be called with preempt disabled
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* and they don't touch the preempt state on their own.
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* If you enable preemption after __kernel_fpu_begin(), preempt notifier
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* should call the __kernel_fpu_end() to prevent the kernel/user FPU
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* state from getting corrupted. KVM for example uses this model.
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*
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* All other cases use kernel_fpu_begin/end() which disable preemption
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* during kernel FPU usage.
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*/
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extern void __kernel_fpu_begin(void);
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extern void __kernel_fpu_end(void);
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extern void kernel_fpu_begin(void);
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extern void kernel_fpu_end(void);
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extern bool irq_fpu_usable(void);
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/*
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* Some instructions like VIA's padlock instructions generate a spurious
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* DNA fault but don't modify SSE registers. And these instructions
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* get used from interrupt context as well. To prevent these kernel instructions
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* in interrupt context interacting wrongly with other user/kernel fpu usage, we
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* should use them only in the context of irq_ts_save/restore()
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*/
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extern int irq_ts_save(void);
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extern void irq_ts_restore(int TS_state);
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/*
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* Query the presence of one or more xfeatures. Works on any legacy CPU as well.
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*
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* If 'feature_name' is set then put a human-readable description of
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* the feature there as well - this can be used to print error (or success)
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* messages.
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*/
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extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name);
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#endif /* _ASM_X86_FPU_API_H */
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