210 строки
5.8 KiB
C
210 строки
5.8 KiB
C
/*
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* include/asm-x86_64/i387.h
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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_64_I387_H
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#define __ASM_X86_64_I387_H
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#include <linux/sched.h>
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#include <asm/processor.h>
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#include <asm/sigcontext.h>
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#include <asm/user.h>
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#include <asm/thread_info.h>
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#include <asm/uaccess.h>
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extern void fpu_init(void);
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extern unsigned int mxcsr_feature_mask;
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extern void mxcsr_feature_mask_init(void);
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extern void init_fpu(struct task_struct *child);
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extern int save_i387(struct _fpstate __user *buf);
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extern asmlinkage void math_state_restore(void);
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/*
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* FPU lazy state save handling...
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*/
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#define unlazy_fpu(tsk) do { \
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if (task_thread_info(tsk)->status & TS_USEDFPU) \
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save_init_fpu(tsk); \
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else \
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tsk->fpu_counter = 0; \
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} while (0)
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/* Ignore delayed exceptions from user space */
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static inline void tolerant_fwait(void)
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{
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asm volatile("1: fwait\n"
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"2:\n"
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" .section __ex_table,\"a\"\n"
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" .align 8\n"
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" .quad 1b,2b\n"
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" .previous\n");
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}
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#define clear_fpu(tsk) do { \
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if (task_thread_info(tsk)->status & TS_USEDFPU) { \
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tolerant_fwait(); \
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task_thread_info(tsk)->status &= ~TS_USEDFPU; \
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stts(); \
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} \
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} while (0)
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/*
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* ptrace request handers...
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*/
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extern int get_fpregs(struct user_i387_struct __user *buf,
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struct task_struct *tsk);
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extern int set_fpregs(struct task_struct *tsk,
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struct user_i387_struct __user *buf);
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/*
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* i387 state interaction
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*/
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#define get_fpu_mxcsr(t) ((t)->thread.i387.fxsave.mxcsr)
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#define get_fpu_cwd(t) ((t)->thread.i387.fxsave.cwd)
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#define get_fpu_fxsr_twd(t) ((t)->thread.i387.fxsave.twd)
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#define get_fpu_swd(t) ((t)->thread.i387.fxsave.swd)
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#define set_fpu_cwd(t,val) ((t)->thread.i387.fxsave.cwd = (val))
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#define set_fpu_swd(t,val) ((t)->thread.i387.fxsave.swd = (val))
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#define set_fpu_fxsr_twd(t,val) ((t)->thread.i387.fxsave.twd = (val))
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#define X87_FSW_ES (1 << 7) /* Exception Summary */
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/* AMD CPUs don't save/restore FDP/FIP/FOP unless an exception
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is pending. Clear the x87 state here by setting it to fixed
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values. The kernel data segment can be sometimes 0 and sometimes
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new user value. Both should be ok.
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Use the PDA as safe address because it should be already in L1. */
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static inline void clear_fpu_state(struct i387_fxsave_struct *fx)
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{
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if (unlikely(fx->swd & X87_FSW_ES))
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asm volatile("fnclex");
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alternative_input(ASM_NOP8 ASM_NOP2,
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" emms\n" /* clear stack tags */
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" fildl %%gs:0", /* load to clear state */
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X86_FEATURE_FXSAVE_LEAK);
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}
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static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
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{
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int err;
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asm volatile("1: rex64/fxrstor (%[fx])\n\t"
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"2:\n"
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".section .fixup,\"ax\"\n"
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"3: movl $-1,%[err]\n"
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" jmp 2b\n"
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".previous\n"
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".section __ex_table,\"a\"\n"
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" .align 8\n"
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" .quad 1b,3b\n"
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".previous"
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: [err] "=r" (err)
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#if 0 /* See comment in __fxsave_clear() below. */
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: [fx] "r" (fx), "m" (*fx), "0" (0));
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#else
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: [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));
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#endif
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if (unlikely(err))
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init_fpu(current);
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return err;
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}
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static inline int save_i387_checking(struct i387_fxsave_struct __user *fx)
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{
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int err;
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asm volatile("1: rex64/fxsave (%[fx])\n\t"
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"2:\n"
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".section .fixup,\"ax\"\n"
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"3: movl $-1,%[err]\n"
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" jmp 2b\n"
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".previous\n"
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".section __ex_table,\"a\"\n"
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" .align 8\n"
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" .quad 1b,3b\n"
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".previous"
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: [err] "=r" (err), "=m" (*fx)
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#if 0 /* See comment in __fxsave_clear() below. */
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: [fx] "r" (fx), "0" (0));
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#else
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: [fx] "cdaSDb" (fx), "0" (0));
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#endif
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if (unlikely(err) && __clear_user(fx, sizeof(struct i387_fxsave_struct)))
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err = -EFAULT;
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/* No need to clear here because the caller clears USED_MATH */
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return err;
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}
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static inline void __fxsave_clear(struct task_struct *tsk)
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{
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/* Using "rex64; fxsave %0" is broken because, if the memory operand
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uses any extended registers for addressing, a second REX prefix
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will be generated (to the assembler, rex64 followed by semicolon
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is a separate instruction), and hence the 64-bitness is lost. */
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#if 0
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/* Using "fxsaveq %0" would be the ideal choice, but is only supported
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starting with gas 2.16. */
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__asm__ __volatile__("fxsaveq %0"
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: "=m" (tsk->thread.i387.fxsave));
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#elif 0
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/* Using, as a workaround, the properly prefixed form below isn't
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accepted by any binutils version so far released, complaining that
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the same type of prefix is used twice if an extended register is
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needed for addressing (fix submitted to mainline 2005-11-21). */
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__asm__ __volatile__("rex64/fxsave %0"
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: "=m" (tsk->thread.i387.fxsave));
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#else
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/* This, however, we can work around by forcing the compiler to select
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an addressing mode that doesn't require extended registers. */
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__asm__ __volatile__("rex64/fxsave %P2(%1)"
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: "=m" (tsk->thread.i387.fxsave)
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: "cdaSDb" (tsk),
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"i" (offsetof(__typeof__(*tsk),
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thread.i387.fxsave)));
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#endif
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clear_fpu_state(&tsk->thread.i387.fxsave);
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}
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static inline void kernel_fpu_begin(void)
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{
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struct thread_info *me = current_thread_info();
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preempt_disable();
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if (me->status & TS_USEDFPU) {
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__fxsave_clear(me->task);
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me->status &= ~TS_USEDFPU;
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return;
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}
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clts();
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}
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static inline void kernel_fpu_end(void)
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{
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stts();
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preempt_enable();
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}
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static inline void save_init_fpu(struct task_struct *tsk)
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{
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__fxsave_clear(tsk);
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task_thread_info(tsk)->status &= ~TS_USEDFPU;
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stts();
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}
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/*
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* This restores directly out of user space. Exceptions are handled.
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*/
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static inline int restore_i387(struct _fpstate __user *buf)
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{
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return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
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}
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#endif /* __ASM_X86_64_I387_H */
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