diff options
Diffstat (limited to 'arch/x86_64/kernel/i387.c')
| -rw-r--r-- | arch/x86_64/kernel/i387.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/i387.c b/arch/x86_64/kernel/i387.c new file mode 100644 index 000000000000..ba139cac57ce --- /dev/null +++ b/arch/x86_64/kernel/i387.c @@ -0,0 +1,155 @@ +/* + * linux/arch/x86_64/kernel/i387.c + * + * Copyright (C) 1994 Linus Torvalds + * Copyright (C) 2002 Andi Kleen, SuSE Labs + * + * Pentium III FXSR, SSE support + * General FPU state handling cleanups + * Gareth Hughes <gareth@valinux.com>, May 2000 + * + * x86-64 rework 2002 Andi Kleen. + * Does direct fxsave in and out of user space now for signal handlers. + * All the FSAVE<->FXSAVE conversion code has been moved to the 32bit emulation, + * the 64bit user space sees a FXSAVE frame directly. + */ + +#include <linux/config.h> +#include <linux/sched.h> +#include <linux/init.h> +#include <asm/processor.h> +#include <asm/i387.h> +#include <asm/sigcontext.h> +#include <asm/user.h> +#include <asm/ptrace.h> +#include <asm/uaccess.h> + +unsigned int mxcsr_feature_mask = 0xffffffff; + +void mxcsr_feature_mask_init(void) +{ + unsigned int mask; + clts(); + memset(¤t->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct)); + asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave)); + mask = current->thread.i387.fxsave.mxcsr_mask; + if (mask == 0) mask = 0x0000ffbf; + mxcsr_feature_mask &= mask; + stts(); +} + +/* + * Called at bootup to set up the initial FPU state that is later cloned + * into all processes. + */ +void __init fpu_init(void) +{ + unsigned long oldcr0 = read_cr0(); + extern void __bad_fxsave_alignment(void); + + if (offsetof(struct task_struct, thread.i387.fxsave) & 15) + __bad_fxsave_alignment(); + set_in_cr4(X86_CR4_OSFXSR); + set_in_cr4(X86_CR4_OSXMMEXCPT); + + write_cr0(oldcr0 & ~((1UL<<3)|(1UL<<2))); /* clear TS and EM */ + + mxcsr_feature_mask_init(); + /* clean state in init */ + current_thread_info()->status = 0; + clear_used_math(); +} + +void init_fpu(struct task_struct *child) +{ + if (tsk_used_math(child)) { + if (child == current) + unlazy_fpu(child); + return; + } + memset(&child->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct)); + child->thread.i387.fxsave.cwd = 0x37f; + child->thread.i387.fxsave.mxcsr = 0x1f80; + /* only the device not available exception or ptrace can call init_fpu */ + set_stopped_child_used_math(child); +} + +/* + * Signal frame handlers. + */ + +int save_i387(struct _fpstate __user *buf) +{ + struct task_struct *tsk = current; + int err = 0; + + { + extern void bad_user_i387_struct(void); + if (sizeof(struct user_i387_struct) != sizeof(tsk->thread.i387.fxsave)) + bad_user_i387_struct(); + } + + if ((unsigned long)buf % 16) + printk("save_i387: bad fpstate %p\n",buf); + + if (!used_math()) + return 0; + clear_used_math(); /* trigger finit */ + if (tsk->thread_info->status & TS_USEDFPU) { + err = save_i387_checking((struct i387_fxsave_struct __user *)buf); + if (err) return err; + stts(); + } else { + if (__copy_to_user(buf, &tsk->thread.i387.fxsave, + sizeof(struct i387_fxsave_struct))) + return -1; + } + return 1; +} + +/* + * ptrace request handlers. + */ + +int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *tsk) +{ + init_fpu(tsk); + return __copy_to_user(buf, &tsk->thread.i387.fxsave, + sizeof(struct user_i387_struct)) ? -EFAULT : 0; +} + +int set_fpregs(struct task_struct *tsk, struct user_i387_struct __user *buf) +{ + if (__copy_from_user(&tsk->thread.i387.fxsave, buf, + sizeof(struct user_i387_struct))) + return -EFAULT; + return 0; +} + +/* + * FPU state for core dumps. + */ + +int dump_fpu( struct pt_regs *regs, struct user_i387_struct *fpu ) +{ + struct task_struct *tsk = current; + + if (!used_math()) + return 0; + + unlazy_fpu(tsk); + memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct)); + return 1; +} + +int dump_task_fpu(struct task_struct *tsk, struct user_i387_struct *fpu) +{ + int fpvalid = !!tsk_used_math(tsk); + + if (fpvalid) { + if (tsk == current) + unlazy_fpu(tsk); + memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct)); +} + return fpvalid; +} |