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4ee91519e1
Add a helper function that ensures the floating point registers for the current task are active. Use with preemption disabled. While at it, add fpregs_lock/unlock() helpers too, to be used in later patches. [ bp: Add a comment about its intended usage. ] Signed-off-by: Rik van Riel <riel@surriel.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Dave Hansen <dave.hansen@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aubrey Li <aubrey.li@intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: kvm ML <kvm@vger.kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190403164156.19645-10-bigeasy@linutronix.de
45 lines
1.2 KiB
C
45 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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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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#include <linux/preempt.h>
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/*
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* Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It
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* disables preemption so be careful if you intend to use it for long periods
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* of time.
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* If you intend to use the FPU in softirq you need to check first with
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* irq_fpu_usable() if it is possible.
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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 bool irq_fpu_usable(void);
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static inline void fpregs_lock(void)
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{
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preempt_disable();
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}
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static inline void fpregs_unlock(void)
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{
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preempt_enable();
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}
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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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