patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/i387.c

• Lines: 114
• Date: Thu Nov 28 15:53:12 2002
• Orig file: linux-2.4.19/arch/x86_64/kernel/i387.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/x86_64/kernel/i387.c linux-2.4.20/arch/x86_64/kernel/i387.c
@@ -0,0 +1,113 @@
+/*
+ *  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 <asm/processor.h>
+#include <asm/i387.h>
+#include <asm/sigcontext.h>
+#include <asm/user.h>
+#include <asm/ptrace.h>
+#include <asm/uaccess.h>
+
+extern int exception_trace;
+
+/*
+ * The _current_ task is using the FPU for the first time
+ * so initialize it and set the mxcsr to its default
+ * value at reset if we support XMM instructions and then
+ * remeber the current task has used the FPU.
+ */
+void init_fpu(void)
+{
+	struct task_struct *me = current;
+	memset(&me->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
+	me->thread.i387.fxsave.cwd = 0x37f;
+	me->thread.i387.fxsave.mxcsr = 0x1f80;
+	me->used_math = 1;
+}
+
+/*
+ * Signal frame handlers.
+ */
+
+int save_i387(struct _fpstate *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 (!tsk->used_math) 
+		return 0; 
+	tsk->used_math = 0; /* trigger finit */ 
+	if (tsk->flags & PF_USEDFPU) { 
+		err = save_i387_checking((struct i387_fxsave_struct *)buf);
+		if (err) { 
+			if (exception_trace) 
+				printk("%s[%d] unaligned signal floating point context %p\n", 
+					tsk->comm, tsk->pid, buf); 
+			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 *buf, struct task_struct *tsk)
+{
+	empty_fpu(tsk);
+	return __copy_to_user((void *)buf, &tsk->thread.i387.fxsave,
+			       sizeof(struct user_i387_struct)) ? -EFAULT : 0;
+}
+
+int set_fpregs(struct task_struct *tsk, struct user_i387_struct *buf)
+{	
+	if (__copy_from_user(&tsk->thread.i387.fxsave, buf, 
+			     sizeof(struct user_i387_struct)))
+		return -EFAULT;
+	/* mxcsr bit 6 and 31-16 must be zero for security reasons. */
+	tsk->thread.i387.fxsave.mxcsr &= 0xffbf;
+	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 (!tsk->used_math) 
+		return 0;
+	unlazy_fpu(tsk);
+
+	memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct)); 
+	return 1; 
+}