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x86: Move kernel_fpu_using to irq_fpu_usable in asm/i387.h

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This function measures whether the FPU/SSE state can be touched in
interrupt context. If the interrupted code is in user space or has no
valid FPU/SSE context (CR0.TS == 1), FPU/SSE state can be used in IRQ
or soft_irq context too.

This is used by AES-NI accelerated AES implementation and PCLMULQDQ
accelerated GHASH implementation.

v3:
 - Renamed to irq_fpu_usable to reflect the purpose of the function.

v2:
 - Renamed to irq_is_fpu_using to reflect the real situation.

Signed-off-by: Huang Ying <ying.huang@intel.com>
CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Huang Ying
2009-08-31 13:11:54 +08:00
committed by H. Peter Anvin
parent f6909f394c
commit ae4b688db2
2 changed files with 13 additions and 12 deletions
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8
arch/x86/include/asm/i387.h
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@@ -301,6 +301,14 @@ static inline void kernel_fpu_end(void)
preempt_enable();
}
static inline bool irq_fpu_usable(void)
{
struct pt_regs *regs;
return !in_interrupt() || !(regs = get_irq_regs()) || \
user_mode(regs) || (read_cr0() & X86_CR0_TS);
}
/*
* Some instructions like VIA's padlock instructions generate a spurious
* DNA fault but don't modify SSE registers. And these instructions