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910665882f
Especially the irq_ts_save() function is pretty bloaty, generating over a dozen instructions, so uninline them. Even though the API is used rarely, the space savings are measurable: text data bss dec hex filename 13331995 2572920 1634304 17539219 10ba093 vmlinux.before 13331739 2572920 1634304 17538963 10b9f93 vmlinux.after ( This also allows the removal of an include file inclusion from fpu/api.h, speeding up the kernel build slightly. ) Reviewed-by: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
40 lines
1.3 KiB
C
40 lines
1.3 KiB
C
/*
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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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#endif /* _ASM_X86_FPU_API_H */
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