mirror of
https://github.com/torvalds/linux.git
synced 2024-12-26 21:02:19 +00:00
f05e798ad4
Disintegrate asm/system.h for X86. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: H. Peter Anvin <hpa@zytor.com> cc: x86@kernel.org
80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
/*
|
|
* Copyright (C) 1994 Linus Torvalds
|
|
*
|
|
* Pentium III FXSR, SSE support
|
|
* General FPU state handling cleanups
|
|
* Gareth Hughes <gareth@valinux.com>, May 2000
|
|
* x86-64 work by Andi Kleen 2002
|
|
*/
|
|
|
|
#ifndef _ASM_X86_I387_H
|
|
#define _ASM_X86_I387_H
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/hardirq.h>
|
|
|
|
struct pt_regs;
|
|
struct user_i387_struct;
|
|
|
|
extern int init_fpu(struct task_struct *child);
|
|
extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
|
|
extern void math_state_restore(void);
|
|
|
|
extern bool irq_fpu_usable(void);
|
|
extern void kernel_fpu_begin(void);
|
|
extern void kernel_fpu_end(void);
|
|
|
|
/*
|
|
* Some instructions like VIA's padlock instructions generate a spurious
|
|
* DNA fault but don't modify SSE registers. And these instructions
|
|
* get used from interrupt context as well. To prevent these kernel instructions
|
|
* in interrupt context interacting wrongly with other user/kernel fpu usage, we
|
|
* should use them only in the context of irq_ts_save/restore()
|
|
*/
|
|
static inline int irq_ts_save(void)
|
|
{
|
|
/*
|
|
* If in process context and not atomic, we can take a spurious DNA fault.
|
|
* Otherwise, doing clts() in process context requires disabling preemption
|
|
* or some heavy lifting like kernel_fpu_begin()
|
|
*/
|
|
if (!in_atomic())
|
|
return 0;
|
|
|
|
if (read_cr0() & X86_CR0_TS) {
|
|
clts();
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline void irq_ts_restore(int TS_state)
|
|
{
|
|
if (TS_state)
|
|
stts();
|
|
}
|
|
|
|
/*
|
|
* The question "does this thread have fpu access?"
|
|
* is slightly racy, since preemption could come in
|
|
* and revoke it immediately after the test.
|
|
*
|
|
* However, even in that very unlikely scenario,
|
|
* we can just assume we have FPU access - typically
|
|
* to save the FP state - we'll just take a #NM
|
|
* fault and get the FPU access back.
|
|
*/
|
|
static inline int user_has_fpu(void)
|
|
{
|
|
return current->thread.fpu.has_fpu;
|
|
}
|
|
|
|
extern void unlazy_fpu(struct task_struct *tsk);
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
#endif /* _ASM_X86_I387_H */
|