156 lines
3.7 KiB
C
156 lines
3.7 KiB
C
/*
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* linux/arch/x86_64/kernel/i387.c
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*
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* Copyright (C) 1994 Linus Torvalds
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* Copyright (C) 2002 Andi Kleen, SuSE Labs
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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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*
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* x86-64 rework 2002 Andi Kleen.
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* Does direct fxsave in and out of user space now for signal handlers.
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* All the FSAVE<->FXSAVE conversion code has been moved to the 32bit emulation,
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* the 64bit user space sees a FXSAVE frame directly.
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*/
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#include <linux/config.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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#include <asm/sigcontext.h>
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#include <asm/user.h>
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#include <asm/ptrace.h>
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#include <asm/uaccess.h>
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unsigned int mxcsr_feature_mask = 0xffffffff;
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void mxcsr_feature_mask_init(void)
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{
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unsigned int mask;
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clts();
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memset(¤t->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
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asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave));
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mask = current->thread.i387.fxsave.mxcsr_mask;
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if (mask == 0) mask = 0x0000ffbf;
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mxcsr_feature_mask &= mask;
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stts();
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}
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/*
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* Called at bootup to set up the initial FPU state that is later cloned
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* into all processes.
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*/
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void __cpuinit fpu_init(void)
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{
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unsigned long oldcr0 = read_cr0();
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extern void __bad_fxsave_alignment(void);
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if (offsetof(struct task_struct, thread.i387.fxsave) & 15)
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__bad_fxsave_alignment();
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set_in_cr4(X86_CR4_OSFXSR);
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set_in_cr4(X86_CR4_OSXMMEXCPT);
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write_cr0(oldcr0 & ~((1UL<<3)|(1UL<<2))); /* clear TS and EM */
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mxcsr_feature_mask_init();
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/* clean state in init */
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current_thread_info()->status = 0;
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clear_used_math();
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}
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void init_fpu(struct task_struct *child)
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{
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if (tsk_used_math(child)) {
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if (child == current)
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unlazy_fpu(child);
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return;
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}
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memset(&child->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
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child->thread.i387.fxsave.cwd = 0x37f;
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child->thread.i387.fxsave.mxcsr = 0x1f80;
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/* only the device not available exception or ptrace can call init_fpu */
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set_stopped_child_used_math(child);
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}
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/*
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* Signal frame handlers.
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*/
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int save_i387(struct _fpstate __user *buf)
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{
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struct task_struct *tsk = current;
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int err = 0;
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{
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extern void bad_user_i387_struct(void);
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if (sizeof(struct user_i387_struct) != sizeof(tsk->thread.i387.fxsave))
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bad_user_i387_struct();
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}
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if ((unsigned long)buf % 16)
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printk("save_i387: bad fpstate %p\n",buf);
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if (!used_math())
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return 0;
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clear_used_math(); /* trigger finit */
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if (tsk->thread_info->status & TS_USEDFPU) {
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err = save_i387_checking((struct i387_fxsave_struct __user *)buf);
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if (err) return err;
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stts();
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} else {
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if (__copy_to_user(buf, &tsk->thread.i387.fxsave,
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sizeof(struct i387_fxsave_struct)))
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return -1;
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}
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return 1;
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}
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/*
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* ptrace request handlers.
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*/
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int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *tsk)
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{
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init_fpu(tsk);
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return __copy_to_user(buf, &tsk->thread.i387.fxsave,
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sizeof(struct user_i387_struct)) ? -EFAULT : 0;
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}
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int set_fpregs(struct task_struct *tsk, struct user_i387_struct __user *buf)
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{
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if (__copy_from_user(&tsk->thread.i387.fxsave, buf,
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sizeof(struct user_i387_struct)))
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return -EFAULT;
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return 0;
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}
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/*
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* FPU state for core dumps.
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*/
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int dump_fpu( struct pt_regs *regs, struct user_i387_struct *fpu )
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{
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struct task_struct *tsk = current;
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if (!used_math())
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return 0;
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unlazy_fpu(tsk);
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memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct));
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return 1;
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}
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int dump_task_fpu(struct task_struct *tsk, struct user_i387_struct *fpu)
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{
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int fpvalid = !!tsk_used_math(tsk);
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if (fpvalid) {
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if (tsk == current)
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unlazy_fpu(tsk);
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memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct));
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}
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return fpvalid;
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}
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