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(&current->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;
+}